Local Action Toolkit - Urban Practitioner's 'Toolbox'

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LOCAL ACTION TOOLKIT Ecosystem services in urban water environments Working with local communities to enhance the value of natural capital in our towns, cities and other urban spaces to improve people’s lives, the environment and economic prosperity.

Urban Practitioner’s ‘Toolbox’ of Interventions

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CONTENTS: How to use this toolbox: .............................................................................. 3 Elements of the toolbox: ............................................................................... 3 Elements of the interventions: ..................................................................... 4 The Benefits Indicators: ................................................................................. 5 Interventions Toolbox – Methods: ............................................................. 6 URBAN INTERVENTIONS .......................................................................... 8 Swales ............................................................................................................. 9 Amenity Lawns ............................................................................................ 12 Wetlands ...................................................................................................... 15 Trees ............................................................................................................. 19 Retention Ponds/Basins ............................................................................... 25 Detention Ponds/Basins .............................................................................. 28 Intensive Green Roofs ................................................................................. 31 Extensive Green Roofs ................................................................................ 34 Permeable Pavements ................................................................................ 37 Rainwater Harvesting/Water Butts ........................................................... 40

EXISTING GREEN & BLUE INFRASTRUCTURE ................................. 43 Public Parks and Gardens ........................................................................... 44 Community Gardens & Allotments ........................................................... 48 Urban Rivers................................................................................................. 53 Private Gardens ........................................................................................... 57 Access ........................................................................................................... 62

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HOW TO USE THIS TOOLBOX: The toolbox can give you an overview of the benefits of different interventions, guide you towards further literature and give you examples of where an intervention has been used.

It can also help you make decisions about the right way to intervene in your local environment. The benefits wheel shows you the relative contribution a certain type of intervention can make to a specific characteristic of an area. It identifies 12 different benefits, grouped into four categories – social, environmental, economic and cultural – that influence the quality of life.

Using the toolbox to deliver targeted interventions

ELEMENTS OF THE TOOLBOX: The toolbox is made up of a number of tools or “interventions”, each with different characteristics.

Most of them work as actual “interventions” (for example, swales) – i.e., they are meant to be designed and developed specifically for an area to address certain issues, be it as new build or retrofit – but there are a few that are usually “existing assets” (for example, public parks) – i.e., they already exist in the urban landscape and are likely under pressure, for example from development.

These two categories are of course not completely exclusive – there may be existing “interventions” in the landscape that need protection or improvement, or there may be opportunities to develop new “assets”.

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The Benefits Wheel

ELEMENTS OF THE INTERVENTIONS: The Benefits Wheel constitutes 12 different benefit indicators that can be influenced by the intervention, grouped into four categories: social, environmental, economic and cultural. Each of the different benefit indicators is ranked on a scale from 1 to 5, indicating the impact that the intervention can have on it, compared to other interventions.

For example, detention basins score a “2” on the benefit “Habitat Network”, while trees score a “4”. This means that placing trees in the urban landscape can have a greater positive impact on the development/protection of habitats and biodiversity than building a detention basin.

This is a semi-quantitative ranking that does not indicate a percentage, but an indication of the relative contribution the intervention can make on the provision of a certain benefit. The ranking has been assigned on the assumption that the intervention is well planned, designed and maintained. Further information on each of the benefit indicators is given in the detailed “Benefits” section of the tool factsheet.

Add. Ben .& Costs

Costs, Maintenance and Feasibility

Landscape Context

On the next page, each of the benefits is explained in detail.

To address not only surface water flooding but most of the benefits represented in the wheel adequately, you should look at the bigger picture of what you are trying to do in your area. Look at interventions as part of the landscape and think about how you can combine them to achieve optimal outcomes.

This is especially important as interventions come in different shapes and sizes and their respective relative contribution can therefore vary. This section presents examples and ideas on positioning interventions and indicates their function in dealing with surface water.

This section gives you more detail on planning aspects of the intervention. If you know the details of where you would like to install an intervention, you can use this section to select suitable options and find further guidance. Or, if you would like to identify suitable options for installing interventions, you can find initial information on what each intervention needs to work here. More detailed guidance can be found in various guidance documents, for example the Suds Manual published by CIRIA or you can check the references of this section. 

Costs: indicative capital cost. This can vary due to local factors and should only be seen as an indication. Some factors influencing capital cost or in some cases lifetime costs may be given.

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Maintenance: Average maintenance costs per unit are given where available or an indication of magnitude of costs is given. Typical maintenance activities are indicated. Correct maintenance is crucial to guarantee that the intervention can deliver, and detailed information should be sought before it is planned and installed.

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Feasibility: Options of fitting intervention (retrofit or new development) are indicated along with other factors that can influence whether or not an intervention can be delivered successfully.

This section gives information on further important benefits that can be gained from an intervention that are not included in the benefits wheel. It also lays out potential negative effects it can have.

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THE BENEFITS INDICATORS: Each of the twelve wedges of the benefits wheel represents one indicator for the provision of benefits through delivering an intervention or protecting/restoring an existing asset. In the factsheets, details on how the intervention can do this are given along with their references so you can understand what it is that the intervention influences. To get a basic understanding of what the indicators mean, read the table below.

Health: Access

Health: Air

Flood (Surface)

Flood (Rivers & Sea)

Indicates potential to provide accessible, attractive green space (either intervention itself or designated area) and the health benefits arising thereof, or to improve accessibility of existing area

Indicates potential for air quality improvement if used optimally, i.e. wind direction, pollution sources etc. are taken into account

Indicates contribution to reducing surface water flooding through either infiltration, conveyance or storage of runoff. Higher numbers have been assigned to interventions infiltrating runoff, since this reduces the volume of runoff from the start. *

Indicates potential to influence flooding from rivers through providing storage or reducing volume of water the river receives. Important: only takes effect downstream of intervention! Benefits are not likely to be felt locally.

Habitat

Low Flow

Water Quality

Climate Regulation

Indicates the ability to provide habitat for a variety of species (plants & animals) and form part of an urban ecological network

Indicates potential contribution to groundwater recharge or to reduction of pressure on mains water

Indicates the ability to prevent pollution either through breaking down pollutants or reducing polluted runoff

Indicates potential to regulate local air temperatures and store/sequester carbon.

Cultural Activities

Aesthetics

Property Value

Flood Damage

Indicates likelihood to provide opportunity for engagement in cultural activities and/or experience cultural values

Indicates aesthetic value of intervention itself and contribution to appearance of local area

Indicates potential impact on increasing value of property

Indicates contribution intervention can make to reducing severity of flooding (both from rivers and surface water) and therefore damage done

*Surface water flooding is a complex problem, that is not easily represented in one number. It can be mitigated by reducing the volume of water, i.e. infiltrating it or storing it immediately at the source, by leading the water away from vulnerable areas or by collecting it from a bigger area and storing it. For the purposes of this toolbox, the three options are presented on the same scale. It is therefore important to understand what the main issues you are facing are, i.e. where does the water that is causing a problem come from. If you want to control water locally, interventions providing infiltration may be best suited, but if you are looking to a larger scale, these interventions may not be able to fulfil your requirements and you may prefer options storing water. A good way to understand this is by using the SuDs approach regarding site, local and regional control. An indication of where a certain intervention fits in is given in the “Landscape context� section.

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INTERVENTIONS TOOLBOX – METHODS: General Approach The list of interventions was compiled by reviewing existing typologies of green infrastructure components and sustainable drainage systems. They were categorised into “existing assets” and “interventions” based on the likelihood of being implemented as a new feature. Parks, allotments, urban rivers/watercourses and private gardens were classed as “existing assets” as they are usually under pressure from various factors, for example new development. While their size or number may be increased in some cases, it is more often the case that existing ones have to be protected (see for example Smith, 2010; Heritage Lottery Fund, 2014). Throughout the process of collating information, the list of interventions was modified in order to allow for interventions with similar features to be treated together, making the toolbox more manageable and easier to use.

Information was collated from a variety of sources in the grey as well as academic literature. Grey literature was mostly used to provide initial information and signposting to academic publications, but also as a source in its own right, especially where it was published by accredited organisations such as Forest Research or the Environment Agency. A semi-structured literature review using the snowball method was carried out to gain a broad range of information on each intervention respectively. Especially information on costs and maintenance was taken mainly from grey literature, as this is not a topic academic publications are usually concerned with.

Additionally, the Natural England Ecosystem Services Transfer Toolkit and the SuDS Manual (Kellagher et al., 2015) was used to provide an overview as well as limited validation of findings where it was suitable.

Benefits Wheel Indicators To allow comparability and consistency throughout the use of the output from the Local Action Project, and to make the use of the toolbox as simple as possible, the same twelve indicators for benefits were used to describe interventions as for the GIS based needs assessment.

The indicators are given a ranking from 1 to 5 based on the ability of an intervention to increase the provision of certain ecosystem services/benefits from ecosystem services in the urban landscape. This describes its ability to increase a benefit compared to other interventions, with 1 signifying “low/unlikely” and 5 signifying “high/very likely”. Benefit indicators are semi-quantitative measures that allow comparison between different interventions, but not the quantification of the increase of a benefit or the ability to add benefits together. It does also not allow comparison of benefit indicators within a wheel. For example: this means that an intervention ranked 1 on the benefit indicator “Cultural Activities” and 5 on “Aesthetics” is unlikely to contribute to the provision of opportunities for cultural activities, compared to an intervention that is ranked 5. It does not mean that the intervention contributes 5 times as much to an aesthetically pleasing environment than to providing opportunity for cultural activities.

The rankings are based on the collated literature. The value given to each indicator was based on set of characteristics and their comparison within the different interventions. Literature was identified specific to each intervention, however where it was likely that findings could be transferrable (e.g. due to similar characteristics in one aspect), and information on a specific intervention was not easily available, evidence that was not specific to the intervention was accepted. For each indicator, a number of sources were used where possible to provide an overall estimate of the performance of the intervention. More weight was given to academic literature reviews and grey literature from accredited sources presenting evidence, but case study evidence and academic papers were used to complement these.

As a measure of confidence, a “traffic light” system was used to indicate the evidence base the ranking was based on. Each of the indicators on each intervention was given an asterisk in red, amber or green, designating a level of certainty: red meaning little availability of and/or high uncertainty within the literature; amber meaning mainly positive evidence in the literature but little literature available or sometimes uncertainty in literature; green meaning that a strong evidence base confirms the positive influence of the intervention.

Table 1 gives an overview of each indicator and its characteristics.

Limitations While the approach taken was similar to a structured literature review, it did not use the same methods of classifying and weighing different sources in a structured way. Due to time constraints, the literature used was

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limited although a high number of sources was identified and through the use of established sources of grey literature and existing reviews, the overall coverage of evidence should be sufficiently high. This does mean however that opportunities to showcase the multiple and varied benefits that different features of green infrastructure can provide may have been missed. This is even more likely as green infrastructure is a very broad and fluid concept that is dealt with by the academic community using a number of different disciplines, terminologies and approaches. This makes it difficult to gather all relevant data within a limited amount of time.

Additionally, while efforts were made to include broader literature and evidence on urban ecosystem services in general and green infrastructure more specifically, the literature search was focussed on identifying benefits that could be linked to specific interventions, potentially missing evidence that was not clearly related to them.

While the semi-quantitative ranking is based on a comparison of evidence, it is still biased as evidence is weighed by the researcher, influencing the ranking. To make this evident to the user and to enable further referencing, the confidence measurements were used.

Indicator

Description

Evidence used

Health: Access

potential to provide accessible, attractive green space (either intervention itself or designated area) and the health benefits arising thereof, or to improve accessibility of existing area

Evidence on positive health impacts linked to specific intervention, evidence on use of intervention for physical activity, evidence on potential to provide accessible green spaces, evidence to increased use of greenspaces due to intervention

Health: Air

potential for air quality improvement if used optimally, i.e. wind direction, pollution sources etc. are taken into account

Evidence on pollutant removal of specific or similar intervention, evidence on air quality, evidence on air quality related health benefits

Flood (Surface)

contribution to reducing surface water flooding through either infiltration, conveyance or storage of runoff. Higher numbers have been assigned to interventions infiltrating runoff, since this reduces the volume of runoff from the start

Evidence on infiltration rates and volume reduction, evidence on peak flow attenuation, evidence on storage. This is a very difficult indicator as surface water flooding can be mitigated in various ways and on various scales. Using a single number to represent this is difficult. Awareness of the detailed description given is therefore important as well as of the causes and symptoms of the surface water flooding situation one is trying to tackle using these interventions.

Flood (Rivers & Sea)

Indicates potential to influence flooding from rivers through providing storage or reducing volume of water the river receives

Evidence on ability to influence flood management and reduction of runoff of intervention itself or similar interventions

Habitat

Indicates the ability to provide habitat for a variety of species (plants & animals) and form part of an urban ecological network

Evidence for species numbers and species rareness found linked to intervention, evidence for habitat value, evidence for use as stepping stones

Low Flow

Indicates potential contribution to groundwater recharge or to reduction of pressure on mains water

Evidence for infiltration and groundwater recharge, evidence for flow regulation, evidence for decreased use of mains water (ultimately reducing abstraction) of intervention itself or similar interventions

Water Quality

Indicates the ability to prevent pollution either through breaking down pollutants or reducing polluted runoff

Evidence for infiltration of polluted runoff (reducing amount of pollutants reaching surface water), evidence on breakdown of pollutants in intervention, evidence of reduced pollutants in runoff

Climate Regulation

Indicates potential to regulate local air temperatures and store/sequester carbon.

Evidence on reducing temperatures, evidence of positive impact on UHI, evidence on carbon sequestration/storage in intervention or similar interventions

Cultural Activities

Indicates likelihood to provide opportunity for engagement in cultural activities and/or experience cultural values

Evidence on cultural values connected to intervention, evidence on activities relating to cultural benefits, evidence on use of intervention as meeting points

Aesthetics

Indicates aesthetic value of intervention itself and contribution to appearance of local area

Evidence on aesthetic value of intervention, evidence on opportunity for design and creation

Property Value

Indicates potential impact on increasing value of property

Evidence on increased property values linked to intervention or similar interventions

Flood Damage

Indicates contribution intervention can make to reducing severity of flooding (both from rivers and surface water) and therefore damage done

Combination of evidence on surface water flooding and fluvial flooding, taking into account the scale on which the intervention works

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URBAN INTERVENTIONS

Image: John Lord (CC BY 2.0)

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SWALES Swales are linear, shallow channels designed to collect and convey rainwater. They also provide pollutant removal and infiltration to some extent. Vegetation and sedimentations removes suspended solids, dissolved pollutants infiltrate with the water into the soil and can so be removed. Three types of swale can be distinguished: Attenuation/conveyance swales, dry swales and wet swales. They each are designed to optimise different aspects of water management. Attenuation/conveyance swales usually do not provide treatment or amenity/ecological benefits, they resemble conventional drainage ditches. Dry swales can be grassed and then are more resembling conventional drainage ditches as well, providing less treatment and flow reduction, or vegetated. Vegetated swales usually feature high grasses and shrubby vegetation, slowing water flow and enabling sedimentation as well as providing more visual and ecological benefits.

Benefits Wheel

Landscape context In the landscape, swales act as connecting elements between other elements of rainwater treatment. While they do provide some storage and treatment, they are best suited to accept runoff from an area – for example, a car park – and lead it into further structures like detention basins or ponds. They can replace conventional pipework in this function.

Whether swales can only work as conveyance or also to reduce/treat runoff is determined by the infiltration capacity of the soil. They are ideal for industrial sites as pollution incidents are easily visible. Downstream treatment components should be incorporated.

Shows the contribution of swales to the provision of ecosystem services.

More detail on the next page.

Costs

Featured Case Study

£10-20/m2. Medium land take, linear structures allow high adaptability. (7)

Maintenance £0.1/acre for regular maintenance, marginally higher for remedial or intermittent maintenance. Mowing, litter and debris removal. Clearing of inlets and outlets. May need removal of sediment. Can be included in landscaping costs. (7)

Hollington Primary School, Hastings This school on a sloping site had suffered considerable flood damage due to overland flows entering the site from residential areas above. Additionally, residential parts of the catchment below the school are also prone to flooding and run off from and passing through the school site is a contributory factor. The SuDS intercept these flows and divert them, over land, to a system of storage, conveyance and flow control comprising an innovative playground storage area, storage swales and rain garden basins that create a dynamic school environment with enhanced learning potential and increased biodiversity.

More: http://www.susdrain.org/casestudies/case_studies/hollington_primary_school_hastings.html

Feasibility Retrofit & high density development possible. Land take limits suitability.

Performance depends on the length of the swale in flow direction and vegetation. Hydraulic connectivity must be ensured, not suitable for steep areas or large amounts of storm water and high pollution. (1,9)

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Social Benefits

Environmental Benefits

Health: Access. * Depends on the design of the swale and its surroundings, but swales can provide accessible small greenspaces. This is often in the context of a larger green area and the impact of the swale itself can therefore not be seen separately. (1)

Water Quality. * Swales perform well removing TSS (usually above 65%) and metals but less for nutrients (30-40% or less, with P showing better removal than N). Fine particles are often not captured. Accumulation of pollutants can be a problem. Vegetated swales are sometimes said to perform better.(2,4,5,9,10,13)

Air Quality. * Vegetation of any kind takes up pollutants from the air. Closely mown grass is unlikely to contribute significantly. (14)

Surface Water. * Swales can infiltrate 40% of all rainfall events and reduce runoff for an additional 40%, with an overall volume reduction of 50-60% - often low peak discharge or volume control provided by swales. This depends on their design. (1,2,6,9,11,12,13)

Fluvial Flood. * Swales have no impact on fluvial flooding.

Habitat Provision. * Can function as green corridors and provide habitat to different species. Especially use of native plants and varied vegetation is valuable. (1,8)

Climate Regulation. * Evaporation can have positive effects on UHI effect. Little carbon storage possible.(15)

Low Flows. * Groundwater recharge is usually provided, but care has to be taken to prevent pollution. Water from swale can be discharged into streams and so directly improve low flows – depends on water quality. (1,13)

Cultural Benefits

Economic Benefits

Aesthetics. * Depends on design. Higher growing native vegetation can provide interesting meadow-like appearances.

Meandering swales have a more natural look. The design can easily be adapted to suit surroundings. (1, 9)

Property Value. * Swales are unlikely to contribute much to property value.

Cultural Activities. * Can be used as an educational resource, design of the swale should take this into account.

Case studies have demonstrated the use of swales as “outdoor classrooms” etc. (1, 9)

Flood Damage. * Through their impact on reducing and removing surface water runoff, swales can reduce severity of surface water floods.

Additional Benefits and Potential Costs No additional benefits

Water quality. In peak events, nutrients and metals can be released from the swale and reach watercourses. Correct design and maintenance should work to prevent this.

Aesthetics. If maintenance and plant selection is not careful, the swale’s appearance could deteriorate. For swales near roadsides, salt resistant plants should be chosen to be able to survive de-icing in winter.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

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References: (1)

http://www.susdrain.org/delivering-suds/usingsuds/suds-components/swales-and-conveyancechannels/swales.html

(2)

Ahiablame, L. M., Engel, B. A. and Chaubey, I. (no date) Effectiveness of Low Impact Development Practices: Literature Review and Suggestions for Future Research.

(3)

Ashley, R. M., Nowell, R., Gersonius, B. and Walker, L. (2011) ‘Surface Water Management and Urban Green Infrastructure’, 44(0), pp. 1–76.

(4)

Berwick, N. and Wade, D. R. (2013) A Critical Review of Urban Diffuse Pollution Control : Methodologies to Identify Sources , Pathways and Mitigation Measures with Multiple Benefits.

(5)

(6)

Deletic, A. (2005) ‘Sediment transport in urban runoff over grassed areas’, Journal of Hydrology, 301(1-4), pp. 108–122.

Ellis, J. B., Shutes, R. B. E. and Revitt, M. D. (2003) Constructed Wetlands and Links with Sustainable Drainage Systems.

(7)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(8)

Kazemi, F., Beecham, S. and Gibbs, J. (2011) ‘Streetscape biodiversity and the role of bioretention swales in an Australian urban environment’, Landscape and Urban Planning, 101(2), pp. 139–148.

(9)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B., Woods Ballard, B., Construction Industry Research and Information Association, Great Britain, Department of Trade and Industry and Environment Agency (2015) The SUDS manual, CIRIA. London.

(10) Lucke, T., Mohamed, M. and Tindale, N. (2014) ‘Pollutant Removal and Hydraulic Reduction Performance of Field Grassed Swales during Runoff Simulation Experiments’, Water. Multidisciplinary Digital Publishing Institute, 6(7), pp. 1887–1904.

(11) Pratt, C. J. (2004) Sustainable Drainage. A Review of Published Material on the Performance of Various SUDS Components. Bristol.

(12) Qin, H., Li, Z. and Fu, G. (2013) ‘The effects of low impact development on urban flooding under different rainfall characteristics.’, Journal of environmental management, 129, pp. 577–85.

(13) Stagge, J. H., Davis, A. P., Jamil, E. and Kim, H. (2012) ‘Performance of grass swales for improving water quality from highway runoff.’, Water research, 46(20), pp. 6731–42.

(14) Forest Research (no date) Improving Air Quality.

(15) Lehmann, S. (2014) ‘Low carbon districts: Mitigating the urban heat island with green roof infrastructure’, City, Culture and Society, 5(1), pp. 1– 8.

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AMENITY LAWNS Amenity grassland is usually intensively managed, closely mown grassland found in parks, sports grounds, village greens or around buildings. It provides a permeable surface and so enables source control and infiltration.

Vegetation can filter and trap sediments.

Benefits Wheel

Landscape context Grassed areas intercept runoff and allow infiltration while also slowing flows down. Impermeability of urban areas is one of the main factors in exacerbating surface water flooding. The cumulative effect of vegetated areas in infiltrating runoff can mitigate this, although it has to be taken into account that waterlogged soils will effectively be impermeable. Amenity areas are present along roadsides, under trees, in public open spaces and as recreation grounds.

Designing amenity areas with surface water in mind can help maximise the benefits. Slightly depressed areas can provide attenuation and collect runoff from additional areas (in effect working similar to detention basins or swales) and keeping open, vegetated areas alongside rivers provides a space to safely attenuate floods.

Shows the contribution of amenity lawns to the provision of ecosystem services. More detail on the next page.

Costs £0.07/m2 – £0.6/m2.

Factors: Instalment of a new lawn may include stripping down old one. Options for establishing new grass area are natural colonisation (minimal cost), grass seed mixtures and turf. (16)

Maintenance

Feasibility

1,600-2,200£/ha/a (0.02-0.22£/m2/a).

Depends on how it is maintained (hand/gang mown, frequency). Mowing, intensity depends on aesthetic requirements. However, maintenance costs likely to increase proportionally with smaller size. (17)

Suitable in all areas, any size, as long as soil infiltration rates are sufficiently high.

If high footfall is expected or vehicular access necessary, soil can be structurally strengthened (increasing cost). Infiltration rates depend on soil type and intensity of use. High groundwater levels can slow infiltration down.

Featured Case Study

More Meadows, Birmingham & Black Country This report investigates the opportunities for amenity grassland in parks and open spaces to be managed for biodiversity and wildlife. Social benefits arise from the use of local volunteers and engaging park staff, enhancing social cohesion and sense of place.

The project showcases the importance of engagement of the local community and staff and generating understanding of the project objectives prior to implementation.

More: www.bbcwildlife.org.uk/sites/default/files/grasslands.pdf Image: BBC

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Social Benefits

Environmental Benefits

Health: Access. * Potential for dual use as sports ground or similar. Amenity lawns should be highly accessible, but design and maintenance are important factors. (1,10)

Water Quality. * Sediment and pollutants can be trapped and to an extent degraded in the soil. However, fertilisation and pesticide application can impact water quality negatively.

(2,4,7,12,14)

Air Quality. * Vegetation and soil can trap air pollutants and dust. (5)

Surface Water. * Can be very high when runoff is eliminated, a reduction of up to 99% of runoff compared to asphalt is possible, reducing peak flows and flow volume. This may be compromised by high footfall on the area and subsequent compaction as well as soil type. Once soil becomes waterlogged, area acts as impermeable surface.

(1,2,3,4,5,9,12,14)

Habitat Provision. * Invertebrates can find habitat in highly managed grassed areas, for other animals (e.g. birds) it is likely the area would have to be less managed (e.g. transformed into rough grassland). Adding structural diversity can provide significant benefits. (4,6, 13, 15)

Climate Regulation. * Surface temperatures of grassed areas are much lower (up to 25dC) than asphalt. Additionally, carbon can be sequestered (in plants and soil), but management activities are likely to offset the net carbon benefits. (4,5,8,19)

Fluvial Flood. * Strategically placed open green spaces can act as storage for fluvial flooding. (2) Low Flows. * Potential for groundwater recharge. (4,5)

Cultural Benefits

Economic Benefits

Aesthetics. * Greenspace can improve the visual quality of urban areas. It is very versatile, but a less interesting feature than other interventions. (1,2,4)

Property Value. * Lawn areas on properties have been shown to add value to properties, but only when well maintained. Lawn in public spaces can also increase rental prices in a neighbourhood. (11)

Cultural Activities. * Potentially important part of cultural spaces, e.g. village greens. Allows cultural activities like picnicking, playing golf, etc. Depends on size and accessibility, although even the view of lawns plays a part in cultural identity and place making. (4,5,10)

Flood Damage. * Taking up water from their own area and surrounding areas can help reduce the risk of flooding and the extent of flooding on a larger scale.

Additional Benefits and Potential Costs Noise reduction. soft lawns can decrease noise by 3db, providing mental and physical health benefits and so improved wellbeing.

Multifunctional. highly multifunctional area that can easily be enhanced by other SuDS/GI and does not have any safety concerns that may come with water bodies.

Health. closely mown grasses have the benefit of less risk of triggering allergies. The proximity of greenspace is beneficial on mental and physical health, improving social wellbeing and saving health related costs. Grass areas are main predictors for the potential of a greenspace to have restorative effects (with size of a greenspace being the most important factor), providing stress relief and an “escape�.

Water quality. Poor maintenance may lead to erosion, litter. This can lead to a decrease in the visual quality and also impact the watercourses the area might drain to, by clogging the soil and increasing pollutant load.

Climate regulation. Dry vegetation can be perceived as ugly or dangerous. Irrigation to counteract this can decrease the ability to infiltrate water, but increases the cooling potential of the area. However, it means a greater demand on water use and energy. This could to an extent be mitigated by rainwater harvesting on site.

Social disbenefits. poor maintenance and design can encourage anti-social behaviour and so have a negative impact on the surrounding areas.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

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References: (1)

CIRIA. (2014). Demonstrating the multiple benefits of SuDS - a business case.

(2)

Woods Ballard, B., Wilson, S., Udale-Clarke, H., Illman, S., Ahsley, R., Kellagher, R. (2015): The Suds Manual. London: CIRIA.

(3)

(4)

(5)

(6)

(7)

(8)

(9)

Armson, D., Stringer, P. and Ennos, A. R. (2013) ‘The effect of street trees and amenity grass on urban surface water runoff in Manchester, UK’, Urban Forestry & Urban Greening, 12(3), pp. 282– 286.

Beard, James B, and Robert L. Green. (1994) “The Role of Turfgrasses in Environmental Protection and Their Benefits to Humans.” Journal of Environment Quality 23 (3). American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America: 452.

Bolund, Per, and Sven Hunhammar. (1999) “Ecosystem Services in Urban Areas.” Ecological Economics 29 (2): 293–301.

Chamberlain, D.E., S. Gough, H. Vaughan, J.A. Vickery, and G.F. Appleton. (2007) “Determinants of Bird Species Richness in Public Green Spaces: Capsule Bird Species Richness Showed Consistent Positive Correlations with Site Area and Rough Grass.” Bird Study 54 (1). Taylor & Francis Group: 87–97.

Davis, A. P., Shokouhian, M., Sharma, H. and Minami, C. (2001) ‘Laboratory study of biological retention for urban stormwater management.’, Water environment research : a research publication of the Water Environment Federation, 73(1), pp. 5–14.

Gill, S.E., M.A. Rahman, J.F. Handley, and A.R. Ennos. (2013) “Modelling Water Stress to Urban Amenity Grass in Manchester UK under Climate Change and Its Potential Impacts in Reducing Urban Cooling.” Urban Forestry & Urban Greening 12 (3): 350–58.

Lamond, Jessica E., Carly B. Rose, and Colin A. Booth. (2015) “Evidence for Improved Urban

Flood Resilience by Sustainable Drainage Retrofit.”

Proceedings of the Institution of Civil Engineers Urban Design and Planning, September. Thomas Telford Ltd.

(10) Nordh, H., Hartig, T., Hagerhall, C. M. and Fry, G. (2009) ‘Components of small urban parks that predict the possibility for restoration’, Urban Forestry & Urban Greening, 8(4), pp. 225–235.

(11) Saphores, Jean-Daniel, and Wei Li. (2012) “Estimating the Value of Urban Green Areas: A Hedonic Pricing Analysis of the Single Family Housing Market in Los Angeles, CA.” Landscape and Urban Planning 104 (3-4): 373–87.

(12) Yang, Jin-Ling, and Gan-Lin Zhang. (2011) “Water Infiltration in Urban Soils and Its Effects on the Quantity and Quality of Runoff.” Journal of Soils and Sediments 11 (5): 751–61.

(13) http://www.newport.gov.uk/en/LeisureTourism/Countryside--Parks/Wildlifewalks/Amenity-grassland.aspx

(14) Susdrain (2016): http://www.susdrain.org/delivering-suds/usingsuds/suds-components/source-control/otherpermeable-surfaces/index.html

(15) Forestry Commission (2016): http://www.forestry.gov.uk/fr/urgc-7edjsm

(16) Costs: http://www.thegrassseedstore.co.uk/environmental /grass-only-meadow/native-meadowgrass.html, http://www.rolawn.co.uk/turf/rolawn-medallionturf?gclid=CNvH5f7OrssCFQcUGwod3v4LA#tabDescription, http://www.turfonline.co.uk/

(17) The Woodland Trust (2011) Trees or Turf ?

(18) Armson, D., Stringer, P. and Ennos, A. R. (2012) ‘The effect of tree shade and grass on surface and globe temperatures in an urban area’, Urban Forestry & Urban Greening, 11(3), pp. 245–255.

15

WETLANDS An urban constructed wetland is a type of blue infrastructure (i.e. consisting of a permanent body of water) that can provide a range of ecosystem services. They are different from ponds in that they have more shallow zones in which bottom-rooted vegetation can grow. Wetlands consist of different zones that are either permanently wet, permanently dry or periodically wet. The periodically wet zone provides room for storing surplus water in high rainfall events. Release of water can be controlled through structures at the outlet of the wetland. In permanently wet zones, vegetation acts as a filter slowing and stabilising suspended solids and adsorbing pollutants. Pollutants are also destroyed by microbial processes or UV radiation.

Benefits Wheel

Landscape context Wetlands are best suitable as the last stage of the treatment process (secondary and tertiary treatment).

They provide infiltration (but only above non-vulnerable groundwater) to an extent and storage.

To function, a wetland needs a continuous water flow.

Artificial as well as natural wetlands store water and provide habitat for different species. Wetlands can be designed to suit various sites and functions, however they generally need a comparatively big area of land to function and keep costs low.

They should always be preceded by other treatment interventions or sediment forebays to ensure aesthetic and hydrologic benefits, and also to keep costs low.

Shows the contribution of wetlands to the provision of ecosystem services.

More detail on the next page.

Costs

Featured Case Study

20-35£/m3 or £15,000-160,000 per wetland. The exact costs depend on design, with high land take and planning costs. (4, 11)

Maintenance 0.1£/m2/a. Removal of litter and potentually silt/sediment, vegetation (pruning etc.). Fences, landscape maintenance. Costs are likely to decline after the first few years. (4)

The Surgery, Kington, Herefordshire In this new development, a Health Centre was build using SuDS treatment to manage surface water. The landscape design involved the creation of areas of new, chiefly native, planting and grassland as well as a series of wetlands acting as part of the storm-water management system on the site.

Employees and patients of the Health Centre are able to enjoy the landscape, including the swales that are located in the staff gardens; however, the wetland is located below the car park and has a post and rail fence restricting access.

More: http://www.susdrain.org/casestudies/case_studies/surgery_kington_herefordshire.html

Feasibility Residential, Industrial (Retrofit – if site conditions make it possible or pocket wetland) Sufficient base flow needs to be provided, low infiltration rates of soil.

They are best used to take runoff from multiple areas after it has undergone primary/secondary treatment. (5,14, 27)

16

Social Benefits

Environmental Benefits

Health: Access. * Can provide highly valuable recreational areas (has been shown to be up to ~63,400£/ha/a) that encourage physical activity and have positive health impacts.

(17,22, 31)

Water Quality. * Effective pollutant reduction: sediment ~90%, nutrients avg. 60% depending on retention time and season. Reduction of hyrdocarbons 50-80%, heavy metals varying but up to 99%. During dry seasons, storm events can wash out pollution w sediment. High water temperature may be an issue. (2,5,6,9,11,13,14,18, 26, 32)

Air Quality. * Potential to reduce air pollution significantly, but few studies on constructed wetlands. (8) Habitat Provision. * Potentially very high but depends on design. Can provide important stepping stones for migratory birds, but depends on size. However, high pollutant loads can compromise this. (18, 19, 22, 24) Surface Water. * Reduction of volume and peak flow potential >80%. Storage area needs to be provided (high land take). Helps to reduce flood impact by delaying high flows but not necessarily reduction in volume. Varying success. Can increase peak flow due to saturation if capacity full.

(5,6,7,9,11,14,22, 23, 28)

Climate Regulation. * High carbon storage potential (up to 2.4kg/m2/yr net), can regulate air temperature and have significant positive effect on UHI. Dense vegetation increases carbon sequestration potential. However, GHG release can potentially occur. (12,16,21,22)

Fluvial Flood. * Can provide flood prevention if positioned upstream/in floodplain areas. Few studies on constructed wetlands. (23, 25)

Low Flows. * Wetlands can increase water flow during dry seasons but may also decrease it. (25)

Cultural Benefits

Economic Benefits

Aesthetics. * Potentially very high if open water is visible.

Water bodies have been shown to provide sense of place, restorative environments and so many cultural benefits.

(17,22, 30, 31)

Property Value. * Can increase property value by up to 28%. Some studies even show up to 300% increase. Increased spending in commercial areas. (11,20)

Cultural Activities. * Potential very high, can be used for angling, birdwatching etc, but depends on design. (17,22, 29)

Flood Damage. * Taking up water from their own area and surrounding areas can help reduce the risk of flooding and the extent of flooding on a larger scale.

Additional Benefits and Potential Costs Mental health – Blue spaces have high impacts on stress levels, and emotional connection to blue spaces is higher than to green spaces. This can strengthen the sense of place and identity and so improve wellbeing.

Educational value – wetlands can provide highly biodiverse, unique habitats and if designed and maintained correctly can be used to educate children and adults about various nature-related topics. The spaces can also be used as outdoor classrooms.

Water re-use – Water stored in wetlands can potentially be re-used for other purposes, e.g. irrigation. This may save energy and water costs.

Pollution - Danger of pollutants being washed out of wetland, higher water temperatures in water body can have impact on aquatic species downstream Safety – if not designed correctly, it can be perceived as a hazard mainly for children.

Aesthetic/Amenity – maintenance needs to be carried out to prevent the wetland from developing odours and accumulating litter and so becoming an eyesore and unwelcoming place.

Habitat – if not enough pre-treatment is provided, pollution of sediments might occur and wildlife might be negatively impacted by the heavy metals etc in the water.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

17

References: (1)

(2)

Ashley, R. M., Nowell, R., Gersonius, B. and Walker, L. (2011) ‘Surface Water Management and Urban Green Infrastructure’, 44(0), pp. 1–76.

Brown, R. G. (1984) “Effects of an Urban Wetland on Sediment and Nutrient Loads in Runoff.”

Wetlands 4 (1): 147–58.

(3)

de Klein, Jeroen J.M., and Adrie K. van der Werf.

(2014) “Balancing Carbon Sequestration and GHG Emissions in a Constructed Wetland.” Ecological Engineering 66 (May): 36–42.

(4)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(5)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B., Woods Ballard, B. (2015) The SUDS manual, CIRIA. London.

(6)

Pratt, C. J. (2004) Sustainable Drainage. A Review of Published Material on the Performance of Various SUDS Components. Bristol.

(7)

Lawrence, A. I., Marsalek, J., Ellis, J. B. and Urbonas, B. (1996) ‘Stormwater detention & BMPs’, Journal of Hydraulic Research. Taylor & Francis Group, 34(6), pp. 799–813

(8)

Forest Research (no date) Improving Air Quality.

(9)

J B Ellis, R B E Shutes and M D Revitt (2003) Constructed Wetlands and Links with Sustainable Drainage Systems.

(10) Malaviya, Piyush, and Asha Singh. (2016) “Constructed Wetlands for Management of Urban Stormwater Runoff Constructed Wetlands for Management of Urban Stormwater Runoff”

(11) CIRIA (2014) ‘Demonstrating the multiple benefits of SuDS - a business case’

(12) Charlesworth, S. M. (2010) ‘A review of the adaptation and mitigation of global climate change using sustainable drainage in cities’, Journal of Water and Climate Change. IWA Publishing, 1(3), p. 165.

(13) Charlesworth, S. M., Harker, E. and Rickard, S. (2003) ‘A Review of Sustainable Drainage Systems (SuDS): A Soft Option for Hard Drainage Questions?’, Geography, 88(2), pp. 99–107.

(14) Ellis, J. B., R. B. E. Shutes, and D. M. Revitt. (2003) “Guidance Manual for Constructed Wetlands.”

(15) Fleming-Singer, Maia S., and Alexander J. Horne.

(2006) “Balancing Wildlife Needs and Nitrate Removal in Constructed Wetlands: The Case of the Irvine Ranch Water District’s San Joaquin Wildlife Sanctuary.” Ecological Engineering 26 (2): 147–66.

(16) Forestry Commission (2013) Air temperature regulation by urban trees and green infrastructure.

Farnham.

(17) Ghermandi, Andrea, and Edna Fichtman. (2015) “Cultural Ecosystem Services of Multifunctional Constructed Treatment Wetlands and Waste Stabilization Ponds: Time to Enter the Mainstream?” Ecological Engineering 84 (November): 615–23.

(18) Helfield, James Mark, and Miriam L. Diamond.

(1997) “Use of Constructed Wetlands for Urban Stream Restoration: A Critical Analysis.”

Environmental Management 21 (3): 329–41.

(19) Hsu, Chorng-Bin, Hwey-Lian Hsieh, Lei Yang, Sheng-Hai Wu, Jui-Sheng Chang, Shu-Chuan Hsiao, Hui-Chen Su, Chao-Hsien Yeh, Yi-Shen Ho, and Hsing-Juh Lin. (2011) “Biodiversity of Constructed Wetlands for Wastewater Treatment.” Ecological Engineering 37 (10): 1533–45.

(20) International Association of Certified Home Inspectors, Inc. (InterNACHI) (2016): Constructed Wetlands: The Economic Benefits of Runoff Controls.

(21) Kayranli, Birol, Miklas Scholz, Atif Mustafa, and Åsa Hedmark. (2009) “Carbon Storage and Fluxes within Freshwater Wetlands: A Critical Review.”

Wetlands 30 (1): 111–24.

(22) Moore, T. L. C. and Hunt, W. F. (2012) ‘Ecosystem service provision by stormwater wetlands and ponds - a means for evaluation?’, Water research, 46(20), pp. 6811–23.

(23) Persson, J., Somes, N. L. G. and Wong, T. H. F. (1999) ‘Hydraulics Efficiency of Constructed Wetlands and Ponds’, Water Science and Technology. IWA Publishing, 40(3), pp. 291–300.

(24) Semeraro, Teodoro, Cosimo Giannuzzi, Leonardo Beccarisi, Roberta Aretano, Antonella De Marco, M. Rita Pasimeni, Giovanni Zurlini, and Irene Petrosillo. (2015) “A Constructed Treatment Wetland as an Opportunity to Enhance Biodiversity and Ecosystem Services.” Ecological Engineering 82 (September): 517–26.

(25) Shutes, B, M Revitt, and L Scholes. (2009) “Constructed Wetlands for Flood Prevention and Water Reuse.”

(26) Shutes, R.B.E. (2001) “Artificial Wetlands and Water Quality Improvement.” Environment International 26 (5-6): 441–47.

(27) U.S. Environmental Protection Agency (2009) Stormwater Wet Pond and Wetland Management Guidebook.

(28) Villarreal,

E. L., Semadeni-Davies, A. and Bengtsson, L. (2004) ‘Inner city stormwater

18 control using a combination of best management practices’, Ecological Engineering, 22(4-5), pp. 279– 298.

(29) Völker, S. and Kistemann, T. (2013) ‘“I’m always entirely happy when I'm here!” Urban blue enhancing human health and well-being in Cologne and Düsseldorf, Germany.’, Social science & medicine (1982), 78, pp. 113–24.

(30) Völker, S. and Kistemann, T. (2015) ‘Developing the urban blue: Comparative health responses to blue and green urban open spaces in Germany’, Health & Place, 35, pp. 196–205.

(31) White, M., Smith, A., Humphryes, K., Pahl, S., Snelling, D. and Depledge, M. (2010) ‘Blue space: The importance of water for preference, affect, and restorativeness ratings of natural and built scenes’, Journal of Environmental Psychology, 30(4), pp. 482–493.

(32) Wong, T., Breen, P. and Somes, N. (1999) ‘Ponds vs Wetlands - Performance Considerations in Stormwater Quality Management’, in Comprehensive Stormwater and Aquatic Ecosystems Management. Auckland, pp. 223–231.

19

TREES Trees can provide a number of different services that depend on their size, species, and location. Their leaves can trap air pollutants either through taking them up or through deposition, thus removing them from the surrounding air. They also intercept rainfall and so slow the rate with which water reaches the ground, increasing infiltration where permeable surfaces are available and additionally reducing runoff through evaporation and root uptake. Through their wide variation in shape, size and demands they are very versatile and can be used in multiple settings. Trees are generally perceived as aesthetically pleasing additions to the landscape and thus provide many less tangible benefits that increase quality of life considerably.

Benefits Wheel

Landscape context Studies have shown that trees can reduce runoff by 62% compared to the same area of naked asphalt, and a 5% increase in tree cover in an area can reduce total runoff by 2%.

Trees act as interception and source control, reducing the runoff generated on a local scale. Water that is not intercepted can infiltrate into the tree pit and be led into storage structures or further treatment. To provide a comprehensive treatment and management of surface water, trees should be seen within the wider landscape.

While they are able to intercept rainfall before it becomes runoff, it is important to understand that their ability to take up existing runoff and infiltrate it is limited and they should be complemented with additional interventions.

Shows the contribution of trees to the provision of ecosystem services.

More detail on the next page.

Costs £15-400 per singular tree (including planting costs). Relative costs decrease with increasing number of trees (potent. below this).

Featured Case Study

Dependent on: Species and age of the tree, location of planting.

Maintenance 0.1£/m2 for managed woodland in managed greenspace. Higher for singular trees. (31,32) Main costs: Pruning Maintenance will be lower the better the tree is suited to the conditions – e.g. soil type, water supply, size of tree pit

Benefits of Trees in the Victoria BID, London Existing trees, green spaces and other green infrastructure assets in Victoria divert up to 112,400 cubic metres of storm water runoffs away from the local sewer systems every year. This is worth between an estimated £20,638 and £29,006 in reduced CO2 emissions and energy savings every year.

The total structural value of all trees in Victoria, (which does not constitute a benefit provided by the trees, but rather a replacement cost) currently stands at £2,103,276. The trees in Victoria remove a total of 1.2 tonnes of pollutants each year and store 847.08 tonnes of carbon.

More: https://www.itreetools.org/resources/reports/VictoriaUK_BID_iTree.pdf

Feasibility Interception and infiltration components for small area, can be combined with similar types of SuDS or stand alone. An open tree pit helps water and oxygen supply. Soil compaction should be avoided. (33,34)

20

Social Benefits

Environmental Benefits

Health: Access. * While trees are not themselves ‘accessible’, they make areas more attractive. Streets with trees have 20% higher bicycle traffic than those without (26).

Parks with a number of trees are used more than those without, however dense tree stands can increase fear of crime.(1,2,3,4,5,6,8,9,7)

Water Quality. * By allowing increased infiltration, trees improve water quality. Leaf litter on the ground reduces soil erosion, trees intercept pollutants and infiltrate them.

(27,28,37)

Air Quality. * A single tree can reduce PM concentration by 15-20%. Street trees reduce prevalence of asthma in children and death rates from respiratory diseases. (9,16,30)

Surface Water. * 10-15% of rainfall are intercepted by canopies (2,000-3,000 litres per year, according to US studies (15)). Open tree pits increase infiltration, with leaf litter acting like a sponge, and so reduces runoff even further (up to 62% reduction of total rainfall volume on area, compared to 10-20% for asphalt). In severely compacted soils, tree roots can improve infiltration by 153%. (13,14,28, 29,33,37)

Habitat Provision. * Depends on location, size and species of tree, but can provide important corridors. Especially large trees are of high importance for biodiversity. Preservation of trees in developments and preservation of especially larger areas of existing woodland can have a high impact on urban biodiversity.) (22,23,24)

Climate Regulation. * Reduce air temperature/UHI (increasing green cover by 10% reduces temperatures by 3 degrees, areas under canopies can be 1-10 degrees cooler than open areas). iTree studies in the UK have estimated annual C sequestration to be 3.65 – 7.4kg/tree. (19,20,21)

Fluvial Flood. * Trees along river banks (i.e. in the riparian zone) can act to slow water flow and reduce fluvial flooding.

Low Flows. * Infiltration allows groundwater recharge or releases water slowly into the water bodies. This can mean a positive impact on low flows.

Cultural Benefits

Economic Benefits

Aesthetics. * Aesthetic benefits have been proven multiple times, impact on mental health (people feel more relaxed in areas with trees), place shaping. (7,12,37)

Property Value. * Trees in the surrounding environment can lead to a 5-10% increase in property value, and increase spending in business areas making areas more attractive to businesses. (10,11,37)

Cultural Activities. * Trees can be important cultural assets and facilitate some cultural activities. This is dependent on their context – for example, old trees that are part of village greens may have different cultural meanings than newly planted street trees. (12)

Flood Damage.* Due to their impact on surface water flooding, trees can influence the extent of a flood – however, singular trees are unable to make a big impact and can only contribute little to fluvial flooding.

Additional Benefits and Potential Costs (Mental) Health. Urban parks with trees reduce stress levels more than those without. Trees have positive impacts on exercise regularity. They have also been connected to positive impacts on health of new-borns/maternal health.

Property Value. Potential negative impact on properties (shading, roots, litter), unhealthy trees can pose safety risk.

Trees can also obscure views, leading to less aesthetic value and in some cases even higher perceptions of unsafety.

Energy Savings. Strategically placed trees can reduce cooling/heating costs in buildings and save energy (10% savings on energy costs due to cooling). Shelterbelts can reduce heating costs by up to 18%

Climate Regulation. Release of VOC can have negative impacts on GHG emissions, as can fuel-intense maintenance.

It is therefore important to select the right species and keep maintenance as low carbon as possible.

Noise Reduction. Trees can act as buffers against noise and placed strategically minimise the impact of highly used roads.

Health. Allergy attacks due to pollen are possible and some trees can produce VOCs and increase ozone generation.

Selection of species is important as well as their placing in the urban landscape to avoid trapping of pollutants.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

21

References: Access (1)

Nordh, H., Hartig, T., Hagerhall, C. M. and Fry, G. (2009) ‘Components of small urban parks that predict the possibility for restoration’, Urban Forestry & Urban Greening, 8(4), pp. 225–235.

In densifying cities, small green spaces such as pocket parks are likely to become more important as settings for restoration. The variables most predictive of the likelihood of restoration were the percentage of ground surface covered by grass, the amount of trees and bushes visible from the given viewing point, and apparent park size.

(2)

This paper investigated whether greater tree-canopy cover is associated with reduced risk of poor birth outcomes in Portland, Oregon. We found that a 10% increase in tree-canopy cover within 50. m of a house reduced the number of small for gestational age births by 1.42 per 1000 births (95% CI-0.11-2.72). Results suggest that the natural environment may affect pregnancy outcomes and should be evaluated in future research.

(6)

Commission for Architecture and the Built Environment (2005) ‘Decent parks? Decent behaviour?: The link between the quality of parks and user behaviour Contents Foreword’, pp. 1– 17.

This publication provides practical suggestions for improving public spaces in ways that can help reduce vandalism and other anti-social behaviour. It is informed by research commissioned by CABE Space in 2004. The research, carried out by GreenSpace, involved over twenty local authorities and seventy-five community representatives concerned with green spaces.

Street trees were associated with a lower prevalence of early childhood asthma. This study does not permit inference that trees are causally related to asthma at the individual level.

(7)

Alcock, I., White, M. P., Wheeler, B. W., Fleming, L. E. and Depledge, M. H. (2014) ‘Longitudinal effects on mental health of moving to greener and less green urban areas.’, Environmental science & technology. American Chemical Society, 48(2), pp.

1247–55.

This study used panel data to explore three different hypotheses about how moving to greener or less green areas may affect mental health over time. Moving to greener urban areas was associated with sustained mental health improvements, suggesting that environmental policies to increase urban green space may have sustainable public health benefits.

(4)

Donovan, G. H., Butry, D. T., Michael, Y. L., Prestemon, J. P., Liebhold, A. M., Gatziolis, D. and Mao, M. Y. (2013) ‘The relationship between trees and human health: evidence from the spread of the emerald ash borer.’, American journal of preventive medicine, 44(2), pp. 139–45 Results suggest that loss of trees to the emerald ash borer increased mortality related to cardiovascular and lower-respiratory-tract illness. This finding adds to the growing evidence that the natural environment provides major public health benefits.

(5)

Donovan, G. H., Michael, Y. L., Butry, D. T., Sullivan, A. D. and Chase, J. M. (2011) ‘Urban trees and the risk of poor birth outcomes’, Health and Place, 17(1), pp. 390–393.

Milligan, C. and Bingley, A. (2007) ‘Restorative places or scary spaces? The impact of woodland on the mental well-being of young adults.’, Health & place, 13(4), pp. 799–811.

Engaging with notions of restoration and therapeutic landscapes literatures, the paper maintains that we cannot accept uncritically the notion that the natural environment is therapeutic. Indeed, from this paper it is clear that a range of influences acts to shape young people's relationship with woodland environments, but not all of these influences do so in positive ways.

Health, Wellbeing and Cultural Benefits (3)

Lovasi, G. S., Quinn, J. W., Neckerman, K. M., Perzanowski, M. S. and Rundle, A. (2008) ‘Children living in areas with more street trees have lower prevalence of asthma.’, Journal of epidemiology and community health, 62(7), pp.

647–9.

(8)

University of Washington (2012) ‘Crime and Public Safety. How Trees and Vegetation Relate to Aggression and Violence.’ 1 of 13.

(9)

Faculty of Public Health (2010) ‘Great Outdoors : How Our Natural Health Service Uses Green Space To Improve Wellbeing’, pp. 1–8.

(10) Luttik, J. (2000) ‘The value of trees, water and open space as reflected by house prices in the Netherlands’, Landscape and Urban Planning, 48(34), pp. 161–167.

This study found the largest increases in house prices due to environmental factors (up to 28%) for houses with a garden facing water, which is connected to a sizeable lake. We were also able to demonstrate that a pleasant view can lead to a considerable increase in house price, particularly if the house overlooks water (8–10%) or open space (6–12%). In addition, the analysis revealed that house price varies by landscape type. Attractive landscape types were shown to attract a premium of 5–12% over less attractive environmental settings.

(11) Saphores, J.-D. and Li, W. (2012) ‘Estimating the value of urban green areas: A hedonic pricing analysis of the single family housing market in Los

22 Angeles, CA’, Landscape and Urban Planning, 104(34), pp. 373–387.

This study analyses 20,660 transactions of single family detached houses sold in 2003 and 2004 in the city of Los Angeles, CA, to estimate the value of urban trees, irrigated grass, and non-irrigated grass areas.

(12) Tabbush, P (2010) ‘Cultural Values of Trees, Woods and Forests’ Forest Research.

This report presents the results of a literature review and primary research into the importance of the cultural values of trees, woods and forests for sustainable forest management (SFM). The concept of ‘cultural capital’ emerged as helpful in distinguishing between the values and norms that stakeholders (including visitors and local communities) bring to woodlands (‘embodied cultural capital’), and physical attributes of the woodlands that are of cultural value (‘objectified cultural capital’, or ‘assets’).

Surface Water Management (13) Armson, D., Stringer, P. and Ennos, A. R. (2013) ‘The effect of street trees and amenity grass on urban surface water runoff in Manchester, UK’, Urban Forestry & Urban Greening, 12(3), pp. 282– 286.

This study assessed the impact of trees upon urban surface water runoff by measuring the runoff from 9 m2 plots covered by grass, asphalt, and asphalt with a tree planted in the centre. It was found that, while grass almost totally eliminated surface runoff, trees and their associated tree pits, reduced runoff from asphalt by as much as 62%. The reduction was more than interception alone could have produced, and relative to the canopy area was much more than estimated by many previous studies.

The results from this study show that both grass and trees can effectively cool surfaces and so can provide regional cooling, helping reduce the urban heat island in hot weather. In contrast grass has little effect upon local air or globe temperatures, so should have little effect on human comfort, whereas tree shade can provide effective local cooling.

(18) Davies, H. and Doick, K. (2015) ‘Valuing the carbon sequestration and rainwater interception ecosystem services provided by Britain’s urban trees.’ Bonn.

(19) Forestry Commission (2013) Air temperature regulation by urban trees and green infrastructure.

Farnham.

Vegetation has a key role to play in contributing to the overall temperature regulation of cities. Informed selection and strategic placement of trees and green infrastructure can reduce the UHI and cool the air by between 2ºC and 8ºC, reducing heat-related stress and premature human deaths during high-temperature events.

(20) Nowak, D. J., Greenfield, E. J., Hoehn, R. E. and Lapoint, E. (2013) ‘Carbon storage and sequestration by trees in urban and community areas of the United States’, Environmental Pollution, (178), pp. 229–236.

Urban whole tree carbon storage densities average 7.69 kg C m2 of tree cover and sequestration densities average 0.28 kg C m2 of tree cover per year. Total tree carbon storage in U.S. urban areas (c. 2005) is estimated at 643 million tonnes ($50.5 billion value; 95% CI ¼ 597 million and 690 million tonnes) and annual sequestration is estimated at 25.6 million tonnes ($2.0 billion value; 95% CI ¼ 23.7 million to 27.4 million tonnes).

(14) Davies, H. and Doick, K. (2015) ‘Valuing the carbon sequestration and rainwater interception ecosystem services provided by Britain’s urban trees.’ Bonn.

(21) Lehmann, S. (2014) ‘Low carbon districts: Mitigating the urban heat island with green roof infrastructure’, City, Culture and Society, 5(1), pp. 1– 8. doi: 10.1016/j.ccs.2014.02.002.

(15) Seitz, J. and Escobedo, F. (2014) ‘Urban Forests in Florida : Trees Control Stormwater Runoff and Improve Water Quality’. University of Florida.

The integration of trees, shrubs and flora into green spaces and gardens in the city is particularly important in helping to keep the urban built environment cool, because buildings and pavements increase heat absorption and reflection (what is called the urban heat island effect). Integrated urban development with a focus on energy, water, greenery and the urban microclimate will have to assume a lead role and urban designers will engage with policy makers in order to drastically reduce our cities’ consumption of energy and resources. This paper introduces the holistic concept of green urbanism as a framework for environmentally conscious urban development.

Neighbourhoods with fewer trees have the potential for increased stormwater, pollutants, and chemicals flowing into their water supply and systems, resulting in health risks, flood damage, and increased taxpayers’ dollars to treat the water. In Santa Monica, CA, rainfall interception was measured for 29,229 street and park trees. Researchers found that the trees intercepted 1.6% of total precipitation over a year, providing an estimated value of $110,890 ($3.80 per tree) saved on avoided stormwater costs.

Air quality (16) Forest Research (no date) Improving Air Quality.

Climate Regulation (17) Armson, D., Stringer, P. and Ennos, A. R. (2012) ‘The effect of tree shade and grass on surface and globe temperatures in an urban area’, Urban Forestry & Urban Greening, 11(3), pp. 245–255.

Habitat Provision (22) Alvey, A. A. (2006) ‘Promoting and preserving biodiversity in the urban forest’, Urban Forestry & Urban Greening, 5(4), pp. 195–201.

The potential for urban areas to harbor considerable amounts of biodiversity needs to be recognized by city planners and urban foresters so that management practices that preserve and promote that diversity can be pursued. Management options should focus on

23 increasing biodiversity in all aspects of the urban forest, from street trees to urban parks and woodlots.

(23) Mörtberg, U. and Wallentinus, H.-G. (2000) ‘Redlisted forest bird species in an urban environment — assessment of green space corridors’, Landscape and Urban Planning, 50(4), pp. 215– 226.

The logistic regression models showed that important properties of remnants of natural vegetation were large areas of forest on rich soils, together with connectivity in the form of amounts of this habitat in the landscape. These properties were associated with the green space corridors. Implications for the design of urban green space corridors would be to treat mature and decaying trees and patches of moist deciduous forest as a resource for vulnerable species, and to conserve large areas of natural vegetation together with a network of important habitats in the whole landscape, in this case forest on rich soils, also in built-up areas.

(24) Stagoll, K., Lindenmayer, D. B., Knight, E., Fischer, J. and Manning, A. D. (2012) ‘Large trees are keystone structures in urban parks’, Conservation Letters, 5(2), pp. 115–122.

This study found that (1) large trees had a consistent, strong, and positive relationship with five measures of bird diversity, and (2) as trees became larger in size, their positive effect on bird diversity increased. Large urban trees are therefore keystone structures that provide crucial habitat resources for wildlife. Hence, it is vital that they are managed appropriately. With evidence-based tree preservation policies that recognize biodiversity values, and proactive planning for future large trees, the protection and perpetuation of these important keystone structures can be achieved.

General/broader References (for multiple benefits) (25) Bird, W. (2007) ‘Natural Thinking’, Royal Society for the Protection of Birds, pp. 1–116.

(26) McPherson, E. G., Simpson, J. R., Peper, P. J., Gardner, S. L., Vargas, K. E. and Xiao, Q. (2007) Northeast Community Tree Guide.

Presents benefits and costs for representative small, medium, and large deciduous trees and coniferous trees in the Northeast region derived from models based on indepth research carried out in the borough of Queens, New York City. Average annual net benefits (benefits minus costs) increase with mature tree size and differ based on location: $5 (yard) to $9 (public) for a small tree, $36 (yard) to $52 (public) for a medium tree, $85 (yard) to $113 (public) for a large tree, $21 (yard) to $33 (public) for a conifer.

(27) Roy, S., Byrne, J. and Pickering, C. (2012) ‘A systematic quantitative review of urban tree benefits, costs, and assessment methods across cities in different climatic zones’, Urban Forestry & Urban Greening, 11(4), pp. 351–363.

Urban trees can potentially mitigate environmental degradation accompanying rapid urbanisation via a range of tree benefits and services. But uncertainty

exists about the extent of tree benefits and services because urban trees also impose costs (e.g. asthma) and may create hazards (e.g. windthrow). Few researchers have systematically assessed how urban tree benefits and costs vary across different cities, geographic scales and climates. This paper provides a quantitative review of 115 original urban tree studies, examining: (i) research locations, (ii) research methods, and (iii) assessment techniques for tree services and disservices.

(28) The Mersey Forest (2014) Urban Catchment Forestry: The strategic use of urban trees and woodlands to reduce flooding, improve water quality, and bring wider benefits.

(29) U.S.

Environmental Protection Agency (2013) Stormwater to Street Trees. Washington, DC.

(30) Wang, Y., Bakker, F., de Groot, R. and Wörtche, H. (2014) ‘Effect of ecosystem services provided by urban green infrastructure on indoor environment: A literature review’, Building and Environment, 77, pp. 88–100.

The economic effects of adjoining vegetation and green roofs on climate regulation provided energy savings of up to almost $250/tree/year, while the air quality regulation was valued between $0.12 and $0.6/m2 tree cover/year. Maximum monetary values attributed to noise regulation and aesthetic appreciation of urban green were $20 – $25/person/year, respectively. Of course these values are extremely time- and contextdependent but do give an indication of the potential economic effects of investing in urban green infrastructure.

Guidance (31) The Woodland Trust (2002) ‘Urban woodland management guide 4: Tree planting and woodland creation.’

(32) The Woodland Trust (2011) Trees or Turf ?

The costs of woodland in managed green space are £1,500/ha/a for the first 4 years after establishment, after which they become a cheaper alternative to amenity grassland, reducing annual maintenance costs per hectare to £630.

(33) The Woodland Trust (2015) ‘Practical Guidance: Residential Developments and Trees’.

Planting trees can slow the flow of water and reduce surface water runoff by up to 62 per cent compared to asphalt. A single young tree planted in a small pit over an impermeable asphalt surface can reduce runoff by around 60 per cent, even during the winter when it is not in leaf. Tree roots can increase infiltration rates in compacted soils by 63 per cent, and in severely compacted soils by 153 per cent. A single tree has been estimated to reduce PM concentration by 15-20 per cent. Natural England has estimated that access to quality green space could save around £2.1 billion in health care costs. The presence of trees is perceived as indicating a more cared for neighbourhood and the

24 presence of street trees was associated with a decreased incidence of crime.

(34) Sustrans (no date): Introducing plants and trees into your street.

(35) Forestry Commission (2009) ‘The London Trees and Woodlands Standard Costs .’

(36) Trees for Cities: http://www.treesforcities.org/aboutus/information-resources/benefits-of-urban-trees/

(37) Warwick District Council (2003) ‘The Benefits of Urban Trees. A summary of the benefits of urban trees accompanied by a selection of research papers and pamphlets.’

This briefing note is an attempt to summarise some of the benefits of urban trees. A number of papers relevant to the subject of the benefits of urban trees have, with the kind permission of their authors, been included in the appendices.

25

RETENTION PONDS/BASINS Retention ponds are a type of green/blue infrastructure that feature a permanently wet area of water (i.e. ponds), designed to store water and provide attenuation and treatment, supporting aquatic and emergent vegetation. They empty into a receiving water body. Retention ponds work similar to wetlands but can store more water. Phytoplankton in the water body absorbs soluble pollutants, and sedimentation removes solids from the water column.

Benefits Wheel

Landscape context Ponds provide infiltration and storage, and are most effectively used lower in the ‘catchment’, after water reaching the pond has already gone through pretreatment. They can, however, provide primary, secondary and tertiary treatment. The retention time of permanent water is linked to the effectiveness of pollutant treatment, and the volume of the storage area to its capacity for holding floods.

The intended catchment area should therefore be taken into account when calculating the storage volume of a pond. Their appearance is very variable and should be adapted to the context.

Shows the contribution of retention ponds to the provision of ecosystem services. More detail on the next page.

Maintenance

Feasibility

£15-25/m3 treated water (lowmedium). Depends on site context – sometimes existing natural depressions can be used. Typically high land take (>5ha), but can be designed to be smaller. Long design life (20-50 yrs).

0.5-1£/m2 surface area. Litter and debris removal, sediment removal may be required. Vegetation management.

Outlets and inlets need to be kept free.

If sediment is not removed sufficiently before entering the pond, dredging may be necessary, reducing design life and increasing costs.

Commercial and Residential, Retrofit/high density area unlikely due to high land take. Liner enables installation above vulnerable groundwater. If groundwater table is high, a liner could also improve sedimentation by preventing constant inflow into the pond. Continuous water supply must be given to ensure permanent pool does not dry out.

Featured Case Study

Costs

Ardler Village, Dundee Ardler was originally a Local Authority housing estate built in the late 1960s with over 3200 flats in six multi-storey buildings housing nearly 8000 people. The area suffered economic decline during the 1980s and studies in the 1990s showed high numbers of single parent families and long term unemployment. Dundee City Council bid for funding to prevent irreversible decline and were awarded £85 million to regenerate the area in 1999.

SuDS were used in the regeneration, including two retention ponds and swales, alongside copses of mature trees, sports facilities and “pocket parks” within each neighbourhood.

More: http://greenspacescotland.org.uk/SharedFiles/Download.aspx?pageid=133&m id=129&fileid=74

26

Social Benefits

Environmental Benefits

Health: Access. * Water bodies encourage low intensity activities and the areas around ponds can be designed to offer space for recreational activities. (4, 11, 12, 18, 26, 27)

Water Quality. * Avg sediment removal efficiency of 90%, N 30%, P 50%, metals 50-80%. Depends on the retention time provided by the pond. (2, 4, 5, 8, 9, 11, 16, 17, 21,27)

Air Quality. *Plants in the area surrounding the pond as well as the soil are likely to take up a certain amount of pollutants. (7)

Habitat Provision. * Ponds can harbour wildlife and aquatic vegetation and also function as habitat corridors and stepping stones for wildlife. They perform an ecologically highly important function, especially in the urban environment. (4, 12, 18)

Surface Water. * Provide peak discharge control for small and medium storms (10 yr return period) or even large storms if carefully designed. Performance depends on storage volume permitted. Volume reduction depends on infiltration and storage time. (1, 4, 5, 6, 9, 11, 12, 19, 20, 22, 23)

Fluvial Flood. * By storing water and attenuating peak flow, retention ponds can positively influence the risk of flooding downstream. (4, 11,22,23)

Cultural Benefits

Aesthetics. * Ponds are an aesthetically pleasing landscape feature, providing a sense of beauty and so promoting wellbeing. (4, 11, 12, 13, 18)

Cultural Activities. * Water bodies have been shown to provide opportunity for reflection and social interaction and so are important cultural points if maintained and designed adequately. Can be used as educational facilities. (4, 11, 13, 24, 25, 26)

Climate Regulation. * Water bodies can balance temperatures and mitigate the UHI effect. Vegetation can take up CO2 that can consequently be buried, but Methane and other GHG can also be released. (10, 14, 18)

Low Flows. * Ponds can potentially release water during dry periods, and the possibility to re-use water can reduce pressure on mains water. (4)

Economic Benefits

Property Value. * Can add significant property value to development and increase business and tourism. 150% increase in property value in residential area where view of the water is available. (4, 11, 13, 18)

Flood Damage. * Through their impact on reducing and removing surface water runoff, retention basins can reduce severity of surface water floods.

Additional Benefits and Potential Costs Water re-use. Depending on the water quality, water from ponds can be reused for watering greenspaces or other nonpotable uses.

Mental Health. Bodies of standing and running water (excluding marshes/swamps) have been shown to provide more mental health and aesthetic benefits than built urban environment without water and even in greenspaces, those featuring water are ranked as being more interesting and restorative.

Water quality. Eutrophication in summer. Avoid by providing constant baseflow, prevent runoff of water directly from fertilised areas around pond (e.g. lawns). It is important to provide an initial stage of water treatment (e.g. traps, filter strips, sediment forebays) before runoff is discharged into ponds.

Cultural Activities. If all surrounding area managed intensively, the ecological potential of the intervention sinks.

But, if vegetation is not managed at all, the area may have low potential for recreational activities.

Habitat. Invasive species can be problematic.

Climate. Waterbodies may emit GHG.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

27

References: (1)

Ashley, R. M., Nowell, R., Gersonius, B. and Walker, L. (2011) ‘Surface Water Management and Urban Green Infrastructure’, 44(0), pp. 1–76.

(SuDS): A Soft Option for Hard Drainage Questions?’, Geography, 88(2), pp. 99–107.

(16) Comings, K. J., Booth, D. B. and Horner, R. R. (2000) ‘Storm Water Pollutant Removal by Two Wet Ponds in Bellevue, Washington’, Journal of Environmental Engineering. American Society of Civil Engineers, 126(4), pp. 321–330.

(2)

Berwick, N. and Wade, D. R. (2013) A Critical Review of Urban Diffuse Pollution Control : Methodologies to Identify Sources , Pathways and Mitigation Measures with Multiple Benefits.

(3)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(17) Heal, K. (2000) SUDS Ponds in Scotland -

(4)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B., Woods Ballard, B. (2015) The SUDS manual, CIRIA. London.

(18) Moore, T. L. C. and Hunt, W. F. (2012)

(5)

Pratt, C. J. (2004) Sustainable Drainage. A Review of Published Material on the Performance of Various SUDS Components. Bristol.

(19) Persson, J., Somes, N. L. G. and Wong, T. H. F.

(6)

Lawrence, A. I., Marsalek, J., Ellis, J. B. and Urbonas, B. (1996) ‘Stormwater detention & BMPs’, Journal of Hydraulic Research. Taylor & Francis Group, 34(6), pp. 799–813

(7)

Forest Research (no date) Improving Air Quality.

(8)

Birch, G. F. and Fazelli, M. S. (2006): Efficiency of a Retention/detention Basin to Remove contaminants from Urban Stormwater’, Urban Water Journal, 3.2, 69–77

(9)

J B Ellis, R B E Shutes and M D Revitt (2003) Constructed Wetlands and Links with Sustainable Drainage Systems.

(10) McPhillips, L. and Walter, T.(2015): Hydrologic Conditions Drive Denitrification and Greenhouse Gas Emissions in Stormwater Detention Basins’, Ecological Engineering, 85 (2015), 67–75

(11) Susdrain (2016): http://www.susdrain.org/delivering-suds/usingsuds/sudscomponents/retention_and_detention/retention_p onds.html

(12) CIRIA (2014) ‘Demonstrating the multiple benefits of SuDS - a business case’

(13) Bastien, N. R. P., Arthur, S. and McLoughlin, M. J. (2012) ‘Valuing amenity: public perceptions of sustainable drainage systems ponds’, Water and Environment Journal, 26(1), pp. 19–29.

(14) Charlesworth, S. M. (2010) ‘A review of the adaptation and mitigation of global climate change using sustainable drainage in cities’, Journal of Water and Climate Change. IWA Publishing, 1(3), p. 165.

(15) Charlesworth, S. M., Harker, E. and Rickard, S. (2003) ‘A Review of Sustainable Drainage Systems

Performance Outcomes to Date.

‘Ecosystem service provision by stormwater wetlands and ponds - a means for evaluation?’, Water research, 46(20), pp. 6811–23.

(1999) ‘Hydraulics Efficiency of Constructed Wetlands and Ponds’, Water Science and Technology. IWA Publishing, 40(3), pp. 291–300.

(20) Persson, J. and Wittgren, H. B. (2003) ‘How hydrological and hydraulic conditions affect performance of ponds’, Ecological Engineering, 21(4-5), pp. 259–269.

(21) Sniffer (2004) SUDS in Scotland - The Monitoring Programme.

(22) U.S. Environmental Protection Agency (2009) Stormwater Wet Pond and Wetland Management Guidebook.

(23) Villarreal, E. L., Semadeni-Davies, A. and Bengtsson, L. (2004) ‘Inner city stormwater control using a combination of best management practices’, Ecological Engineering, 22(4-5), pp. 279– 298.

(24) Völker, S. and Kistemann, T. (2013) ‘“I’m always entirely happy when I'm here!” Urban blue enhancing human health and well-being in Cologne and Düsseldorf, Germany.’, Social science & medicine (1982), 78, pp. 113–24.

(25) Völker, S. and Kistemann, T. (2015) ‘Developing the urban blue: Comparative health responses to blue and green urban open spaces in Germany’, Health & Place, 35, pp. 196–205.

(26) White, M., Smith, A., Humphryes, K., Pahl, S., Snelling, D. and Depledge, M. (2010) ‘Blue space: The importance of water for preference, affect, and restorativeness ratings of natural and built scenes’, Journal of Environmental Psychology, 30(4), pp. 482–493.

(27) Wong, T., Breen, P. and Somes, N. (1999) ‘Ponds vs Wetlands - Performance Considerations in Stormwater Quality Management’, in Comprehensive Stormwater and Aquatic Ecosystems Management. Auckland, pp. 223–231.

28

DETENTION PONDS/BASINS Detention ponds or basins are usually dry depressions in the ground that can be vegetated or grey. While usually designed to provide only short term storage of water, their pollutant removal efficiency is higher when they are designed to hold water for longer (they are then called extended detention basins). They do so by allowing sediment to settle and biological processes to take place that destroy nutrients and other pollutants.

Benefits Wheel

Landscape context Detention basins act mainly as storage areas and can provide treatment of water from a larger catchment area.

Surface water can be stored as part of a routine runoff path (‘on-line component’) or they can act to capture overflow when the usual train of treatment is insufficient (‘off-line’), before it is discharged into the sewer system or further treatment.

The intended function influences the design, with on-line components usually being vegetated to provide infiltration and pollutant treatment capacities. To maintain their function, pre-treatment – for example sediment forebays – is necessary.

They can be combined with swales, and including small ponds or wetlands can increase treatment performance.

In addition, they can provide valuable recreational areas.

Shows the contribution of detention ponds to the provision of ecosystem services. More detail on the next page.

Costs

Featured Case Study

15-55£/m3 volume, with a lifetime of up to 50 years. Costs depend on the site and context, as well as the scale of the development. (5)

Maintenance 0.3£/m2/a. Can be part of landscaping.

Inlet and outlet need to be cleaned regularly and sediment monitored and removed if necessary. Regular maintenance is necessary. (5)

Lamb Drove, Cambridgeshire Lamb Drove is a residential development of 35 homes on a one-hectare site. SuDS was incorporated from the start of development (2004) to prove that it can be practical in new residential developments, particularly in Cambridgeshire which is low-lying and has plans for up to 50,000 new homes by 2016.

A range of SuDS components have been used, including permeable pavements, green roofs, swales and detention basins. The Management Train concept was used across the site, this mimics natural drainage as much as possible and aims to control runoff as close as possible to its source.

More: Report: http://robertbrayassociates.co.uk/projects/lamb-drove/

Feasibility Residential, Commercial, Retrofit.

Multiple uses possible and can therefore be incorporated in existing amenity space and used for recreation. (6,14,15)

29

Social Benefits

Environmental Benefits

Health: Access. * Detention basins can be used as multifunctional areas and so provide opportunities for recreation and sport. (2,6,14)

Water Quality. * Especially high sediment removal (40-70%) but also for metals and insoluble pollutants, but lower for soluble pollutants. Higher for extended detention basins. (3, 4, 7, 10, 11)

Air Quality. * Potentially, pollutants can be adsorbed by vegetation and soil. (9)

Surface Water. * Detention basins have a high impact on peak flows and can reduce volume of runoff (20-90%), but are most effective for small storms. Extended detention basins can achieve better outcomes. (7, 8, 10, 11)

Fluvial Flood. * Detention basins may influence fluvial floods downstream by reducing the amount of water discharged into rivers. (2)

Cultural Benefits

Aesthetics. * Depending on design the aesthetic value can be significant. In highly urbanised areas where grey design is required, this can be enhanced to look appealing and provide multifunctional space. (6,13,15)

Cultural Activities. * Depending on design, detention basins can provide space for cultural activities. (6, 14, 15)

Habitat Provision. * Low potential but planting of native vegetation and shrubs can improve habitat conditions for wildlife. Invasive species can be a problem. (6, 13, 15)

Climate Regulation. * DB can reduce the UHI effect and store carbon if vegetated. Long storage times, while improving nutrient removal, can increase GHG emissions. (2, 13,16)

Low Flows. * Groundwater recharge is possible. (6,13)

Economic Benefits

Property Value. * Good design increases property value in close vicinity to detention basins. (11)

Flood Damage. * Through their impact on reducing and removing surface water runoff, detention basins can reduce severity of surface water floods.

Additional Benefits and Potential Costs No additional benefits

Climate Regulation. Depending on the design, NH4 and CH4 can be emitted, more so when storage times are longer.

This should be considered when designing the basin and outlet.

Aesthetics. Lack of maintenance can lead to swampy areas at the outlet of the basin which can be perceived as dangerous or simply ugly, and can also have an impact on the multi-functionality of the space.

Water quality. Sediment removal needs to be taken care of if accumulation of metals happens at the bottom of the basin.

Otherwise, the soil can become contaminated and high pollution can occur in the outflow of the basin.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

30

References: (1)

(2)

(3)

Ahiablame, L. M., Engel, B. A. and Chaubey, I. (2012) Effectiveness of Low Impact Development Practices: Literature Review and Suggestions for Future Research.

Ashley, R. M., Nowell, R., Gersonius, B. and Walker, L. (2011) ‘Surface Water Management and Urban Green Infrastructure’, 44(0), pp. 1–76.

Berwick, N. and Wade, D. R. (2013) A Critical Review of Urban Diffuse Pollution Control : Methodologies to Identify Sources , Pathways and Mitigation Measures with Multiple Benefits.

(4)

Deletic, A. (2005) ‘Sediment transport in urban runoff over grassed areas’, Journal of Hydrology, 301(1-4), pp. 108–122.

(5)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(6)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B., Woods Ballard, B. (2015) The SUDS manual, CIRIA. London.

(7)

(8)

(9)

Pratt, C. J. (2004) Sustainable Drainage. A Review of Published Material on the Performance of Various SUDS Components. Bristol.

Lawrence, A. I., Marsalek, J., Ellis, J. B. and Urbonas, B. (1996) ‘Stormwater detention & BMPs’, Journal of Hydraulic Research. Taylor & Francis Group, 34(6), pp. 799–813 Forest Research (no date) Improving Air Quality.

(10) Birch, G. F. and Fazelli, M. S. (2006): Efficiency of a Retention/detention Basin to Remove contaminants from Urban Stormwater’, Urban Water Journal, 3.2, 69–77

(11) J B Ellis, R B E Shutes and M D Revitt (2003) Constructed Wetlands and Links with Sustainable Drainage Systems.

(12) Lee, J. S. and Li, M. (2009): The Impact of Detention Basin Design on Residential Property Value: Case Studies Using GIS in the Hedonic Price Modeling’, Landscape and Urban Planning, 89.1-2, 7–16

(13) McPhillips, L. and Walter, T.(2015): Hydrologic Conditions Drive Denitrification and Greenhouse Gas Emissions in Stormwater Detention Basins’, Ecological Engineering, 85 (2015), 67–75

(14) Susdrain (2016): http://www.susdrain.org/delivering-suds/usingsuds/sudscomponents/retention_and_detention/Detention_ basins.html

(15) CIRIA (2014) ‘Demonstrating the multiple benefits of SuDS - a business case’, (October), p. 45.

(16) Armson, D., Stringer, P. and Ennos, A. R. (2012) ‘The effect of tree shade and grass on surface and globe temperatures in an urban area’, Urban Forestry & Urban Greening, 11(3), pp. 245–255.

31

INTENSIVE GREEN ROOFS Intensive green roofs are a type of green roof with deeper substrate and shrubby vegetation or even trees.

They are usually accessible and can often take the shape of a garden, which also means they require more maintenance than extensive roofs. They can also include blue roof elements (e.g. rainwater irrigation or water storage features). Due to their deeper substrate, they put higher loads onto roof structures than extensive green roofs, however this also means that they have higher capacities to store water.

Benefits Wheel

Landscape context Intensive green roofs have the same function as any open, permeable surface: they provide interception and source control, and are therefore part of the first stages of treatment. They effectively reduce the impermeable surface of an urban area and act to reduce runoff.

They are able to provide storage to an extent, but need further connection to drainage systems.

Green roofs can be combined with rainwater harvest systems or feature blue spaces – like ponds – that can use the collected runoff. As they cannot receive runoff from adjoining areas, their effect is on a limited scale, but cumulative effects on a wider area should not be underestimated.

Additionally, green roofs can improve wellbeing by reducing air temperature and improving air quality in urban areas.

Shows the contribution of intensive green roofs to the provision of ecosystem services. More detail on the next page.

Costs

Maintenance

Feasibility

£100-140/m2 (high). But can increase the lifetime of roofing compared to conventional roofs by up to three times.

May be higher for retrofit. However, no additional land take is required.

Low to High. Regular inspection needed. May need irrigation and drainage systems. Due to the importance of their appearance, maintenance similar to that of parks or gardens can be required.

Domestic, Industrial, Retrofit possible.

Only on flat roofs. Plants should be carefully selected to minimise irrigation and fertilisation needs. Intensive green roofs need strong roof structures due to their higher weight.

Featured Case Study

Bridgewater Green Roofs, Somerset This report investigates the whole life costs of a living roof (extensive green roof) in Somerset. It compares costs of an exposed roof, a sedum roof and a biodiverse roof and finds that the biodiverse roof achieves the best financial and non-financial results, due to a longer life time and insulation benefits.

It also attracts the widest range of animals and so has the greatest benefits for ecology. It also states that added insulation effects of bio diverse and sedum living roofs will save approximately 4.9t of CO2 per annum or a total of 245t over the life of the living roof.

More: The Solution Organisation (2005): Whole Life Costs & Living Roofs – The Springboard Centre, Bridgewater. http://www.thesolutionorganisation.com/Living%20roof%20Bridgewater%20 003.pdf Image: greenroofs.com

32

Social Benefits

Environmental Benefits

Health: Access. * Accessible intensive green roofs can provide stress relief, space for exercise, and improve mental health. However, access may be restricted. (4,17)

Water Quality. * Overall, they have a positive impact on water quality. Pollution reduction can exceed 90% for various metals and phosphorus up to 64%. First flush effects may occur. (2,4, 5, 13, 16)

Air Quality. * IGR provide high potential for removing pollutants from the air. Studies in Chicago have estimated removal of 50% O3, 27% NO2 and 7% SO2.Through their mix of different vegetation types, IGR have the potential to remove 3x as many pollutants in total compared to those with only grass. Removal depends on season, species, and local factors. (13, 15, 16, 19)

Habitat Provision. * Green roofs can provide important ecological stepping stones and habitats for invertebrates.

Intensive green roofs face more disturbance through maintenance and use. Ecological potential can be maximised through the selection of suitable vegetation. (4,6,11)

Surface Water. * Intensive green roofs are considered to have an attenuation capacity of 90-100%, capturing 70+% of rainfall volume and delaying peak flows. (2,4,5,6,7,10,16,24)

Climate Regulation. * The carbon sequestration/storage potential depends on the vegetation used. Additionally, IGR regulate air temperature – green surface areas can reduce temperatures by up to 3 degrees. (1,4,8,9,13)

Fluvial Flood. * Green roofs are unlikely to contribute to reducing fluvial flooding.

Low Flows. * IGR could even need irrigation and so increase demand on water resources.

Cultural Benefits

Economic Benefits

Aesthetics. * Green roofs can provide the same high aesthetic benefits as public parks or gardens, however there is little literature analysing this benefit. (6,23)

Property Value. * Studies have mentioned increases in property value through installation of green roofs but have not quantified them.

Cultural Activities. * Where access is given, these places can provide settings for social bonding, strengthen communities and potentially allow cultural activities like gardening and farming. (6,17)

Flood Damage. * By reducing the impermeability of an urban area, green roofs can help to reduce severity of floods.

Additional Benefits and Potential Costs Energy saving. Green roofs can reduce temperatures in buildings (up to 75% reduction in cooling demand shown in extensive roofs, and higher for intensive). A case study in Bridgewater, Somerset (see below) estimated a fuel saving of GBP 5.20/m² per year.

Mental health. Green spaces have positive effects on physical and mental health that are related to exercise and the ability to view green/natural areas. Green roofs, can therefore be a contribution to raising quality of life especially in highly urbanised areas.

Noise reduction. Green roofs have been shown to reduce noise. One study has shown a reduction of 8dB. Education. In highly dense urban environments, accessible green roofs can provide a safe and convenient outdoor learning environment that not only gives access to natural habitats but can also increase focus and wellbeing of pupils/students.

Aesthetics vs Runoff control – The wish and need to maintain lush and aesthetically pleasing vegetation can mean that irrigation and/or fertilisation is necessary during dry spells. This may decrease the ability to store/absorb precipitation; increases water consumption and, in the case of fertilisation, decrease the water quality of the runoff. To an extent, this can be avoided by coupling water harvesting systems with green roofs, so that dry periods can be overcome with water from previous storm events. This also increases storage capacity of the roof. If designed adequately, the stored water can even be used to enhance the landscape by providing aesthetically pleasing water features (blue roof).

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

33

References: (1)

(2)

Coutts, A.M. et al., 2013. Assessing practical measures to reduce urban heat: Green and cool roofs. Building and Environment, 70, pp.266–276.

Czemiel Berndtsson, J., 2010. Green roof performance towards management of runoff water quantity and quality: A review. Ecological Engineering, 36(4), pp.351–360.

A runoff reduction of 27-81% for extensive roofs.

Exact amount depends on rainfall intensity, substrate and drainage. Runoff water quality varies greatly but they can contribute significantly to pollutant reduction.

Green roofs can be an effective tool to manage small storms in urbanised areas, but additional measures need to be taken for larger storms.

(3)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(4)

Forest Research, 2010. Benefits of Green Infrastructure, Farnham: Forest Research.

Extensive green roofs can reduce pollution compared to convetional roofs. They can reduce runoff by 45%, and also provide ecological services, being used by birds and invertebrates.

(5)

Glass, C.C., 2007. Green Roof Water Quality and Quantity Monitoring,

(6)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B., Woods Ballard, B. (2015) The SUDS manual, CIRIA. London.

Intensive green roofs require maintenance and are usually accessible. They provide good contribution to thermal performance of buildings, as well as good water retention capacity. Pollution removal is variable.

Can provide great amenity benefits.

(7)

Lamera, C. et al., 2013. Green roof impact on the hydrological cycle components. In EGU 10th General Assembly. p. 8038.

(8)

Lehmann, S., 2014. Low carbon districts: Mitigating the urban heat island with green roof infrastructure. City, Culture and Society, 5(1), pp.1–8

(9)

Liu, K.K.Y. & Baskaran, B., 2003. Thermal performance of green roofs through field evaluation, Ottawa.

(10) Mentens, J., Raes, D. & Hermy, M., 2006. Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century? Landscape and Urban Planning, 77(3), pp.217–226.

(11) Oberndorfer, E., Lundholm, J., Bass, B., Coffmann, R. R., Doshi, H., Dunnett, N., Gaffin, S., Koehler, M., Liu, K. K. Y. and Rowe, B. (2007) ‘Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services’, BioScience. Oxford University Press, 57(10), p. 823.

(12) Red Rose Forest, 2014. University of Manchester Green Roof - Green Wall Policy and Guidance, Manchester.

(13) Rowe, D.B., 2011. Green roofs as a means of pollution abatement. Environmental pollution, 159(8-9), pp.2100–10.

Comprehensive literature review of peer reviewed English language literature. Up to 0.5kg of PM/m2 are removed by grassed green roofs. Intensive roofs reduce even more – vegetation plays a key role. They can also sequester carbon, however their construction is often more carbon intensive than those of conventional roofs.

Green roofs can effectively retain pollutants like heavy metals by up to 99%, however this depends on their age, time of year and magnitude of rainfall.

(14) Royal Haskoning DHV, 2012. Costs and Benefits of Sustainable Drainage Systems,

(15) Speak, A.F. et al., 2012. Urban particulate pollution reduction by four species of green roof vegetation in a UK city. Atmospheric Environment, 61, pp.283–293.

Green roofs can remove 0.425 (sedum roof) to 3.21g (grass) PM10/m2/a. Intensive roofs have higher impacts than extensive roofs.

(16) U.S. Environmental Protection Agency, 2008.

Green Roofs. In Reducing Urban Heat Islands: Compendium of Strategies. Wasington D.C.: U.S. Environmental Protection Agency.

Studies have shown up to 75% reduction in demand for cooling, and 10% for heating (both studies carried out in Canada). They improve air quality by removing pollutants, studies having shown a removal of 0.2kg of PM/m2/a. They can also reduce heavy metals in runoff by up to 95% and reduce peak runoff as well as total runoff by 50-100%.

(17) Wolch, J.R., Byrne, J. & Newell, J.P., 2014. Urban green space, public health, and environmental justice: The challenge of making cities “just green enough.” Landscape and Urban Planning, 125, pp.234–244.

(18) Wong, N. H., Tay, S. F., Wong, R., Ong, C. L. and Sia, A. (2003) ‘Life cycle cost analysis of rooftop gardens in Singapore’, Building and Environment, 38(3), pp. 499–509.

(19) Yang, J., Yu, Q. & Gong, P., 2008. Quantifying air pollution removal by green roofs in Chicago.

Atmospheric Environment, 42(31), pp.7266–7273.

(20) www.thegreenroofcentre.co.uk/green_roofs/faq (21) http://livingroofs.org/ (22) http://www.greenroofguide.co.uk/ (23) Lee, K. E., Williams, K. J. H., Sargent, L. D., Williams, N. S. G. and Johnson, K. A. (2015) ‘40second green roof views sustain attention: The role of micro-breaks in attention restoration’, Journal of Environmental Psychology, 42, 182–189.

(24) Mentens, J., Raes, D. & Hermy, M., 2006. Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century? Landscape and Urban Planning, 77(3), pp.217–226.

34

EXTENSIVE GREEN ROOFS Green roofs are distinguished into two main categories: intensive and extensive. Extensive green roofs usually feature a thin layer of soil medium and plants like succulents, grasses or other low maintenance, low growing vegetation. They require little to no maintenance and are usually not accessible. By intercepting precipitation and allowing infiltration in the soil media as well as evaporation and transpiration from plants, extensive green roofs reduce the impermeable surface of an area. They are most effective in small to medium rainfall events with low intensities and longer durations.

Benefits Wheel

Landscape context Green roofs have the same function as any open, permeable surface: they provide interception and source control, and are therefore part of the first stages of treatment. They may be able to provide storage to an extent, but will need further connection to drainage systems.

They can be combined with rainwater harvest systems.

They only receive water from the area of the roof.

Shows the contribution of extensive green roofs to the provision of ecosystem services. More detail on the next page.

Costs

Maintenance

ÂŁ55-130/m2 (medium to high). Depends on type - may be higher for retrofit.

Longer life expectancy than conventional roofs (up to 3 times).

Relative costs depend on area, location (and with it the accessibility of the site).

Benefit of not using any additional land.

(3, 6, 14, 18)

Maintenance requirements are minimal if at all. Usually no requirement of artificial irrigation or fertilization.

Invasive species removal may be required, as well as clearing of drains.

(6)

Featured Case Study

Bridgewater Green Roofs, Somerset This report investigates the whole life costs of a living roof (extensive green roof) in Somerset. It compares costs of an exposed roof, a sedum roof and a biodiverse roof and finds that the biodiverse roof achieves the best financial and non-financial results, due to a longer life time and insulation benefits. It also attracts the widest range of animals and so has the greatest benefits for ecology. It also states that added insulation effects of bio diverse and sedum living roofs will save approximately 4.9t of CO2 per annum or a total of 245t over the life of the living roof.

More: The Solution Organisation (2005): Whole Life Costs & Living Roofs – The Springboard Centre, Bridgewater. http://www.thesolutionorganisation.com/Living%20roof%20Bridgewater%20 003.pdf Image: greenroofs.com

Feasibility Residential and Industrial, Retrofit possible. Flat and sloping roofs are possible. Slopes however influence drainage and will lead to less water holding capacity. (6, 12)

35

Social Benefits

Environmental Benefits

Health: Access. * Extensive green roofs are usually not accessible but can provide mental health benefits if they are visible from other places. (4,17)

Water Quality. * The capacity of green roofs to reduce pollutants is linked to their age (more mature roofs capture more pollutants), design, season (removal rates are higher in summer) and species. Overall, they have a positive impact on water quality. Studies have shown retention of PO4 of up to 80%, and retention of heavy metals of 80-99%. Sedum roofs are less effective at reducing pollution than herbaceous perennials. (2,4, 5, 13, 16)

Air Quality. * Sedum covered green roofs can remove up to 200g PM/a/m2 from the atmosphere and provide benefits through the improvement of air quality. Different types of vegetation can account for even higher reductions. Studies have shown that 19m2 of extensive green roof can reduce pollution by the same amount as a medium sized tree. (13, 15, 16, 19)

Surface Water. * About 50% (27-81%) of runoff can be retained in small to medium rainfall events by extensive green roofs, depending on soil thickness and vegetation characteristics. A study in Brussels has shown that greening only 10% of possible roofs would lead to overall runoff reduction of 2.7%. (2, 4, 5, 6, 7, 10, 16)

Habitat Provision. * Green roofs can provide important ecological stepping stones for wildlife and habitats to a number of even endangered invertebrates. This depends on their design and species selection as well as maintenance. (4, 6, 11)

Climate Regulation. * Green roofs can reduce temperatures (up to 75% reduction in cooling demand shown).

They impact positively on the UHI effect by lowering the air temperature (vegetated areas can decrease air temperatures by up to 3 degrees). Depending on their vegetation, they can store and sequester carbon. (1, 4, 8, 9, 13)

Fluvial Flood. * Not given.

Low Flows. * Not given.

Cultural Benefits

Economic Benefits

Aesthetics. * Ext. green roofs can be designed to be aesthetically pleasing.

Property Value. * Studies have mentioned increases in property value through installation of green roofs but have not quantified them.

Cultural Activities. * As they are usually not accessible, ext. green roofs have little potential to provide cultural benefits.

Flood Damage. * By reducing the impermeability of an urban area, green roofs can help to reduce severity of floods.

Additional Benefits and Potential Costs Energy savings. Depending on temperature, green roofs can provide substantial energy savings by cooling a building in summer (up to 75%0 and providing isolation in winter (up to 10%). Electricity savings could amount to £5.20/m2/yr. They could play an important role in adapting cities to climate change.

Water quality. Runoff can include high pollution loads from green roofs than can either be a symptom of the “first flush” effect after longer dry periods, due to the vegetation or – in some cases – fertilization. Care needs to be taken to avoid this through informed design.

Mental health. The view of green roofs can provide relaxation and restoration and so have beneficial effects on the mental health of those in vicinity.

Noise reduction. Green roofs can impact on acoustic transfer into and out of a building. *** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

36

References: (1)

(2)

Coutts, A.M. et al., 2013. Assessing practical measures to reduce urban heat: Green and cool roofs. Building and Environment, 70, pp.266–276.

Czemiel Berndtsson, J., 2010. Green roof performance towards management of runoff water quantity and quality: A review. Ecological Engineering, 36(4), pp.351–360.

Numerous studies show a runoff reduction of 27-81% for extensive roofs. Exact amount depends on rainfall intensity, substrate and drainage. Runoff water quality varies greatly but they can contribute significantly to pollutant reduction. Green roofs can be an effective tool to manage small storms in urban areas, but additional measures required for larger storms.

(3)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(4)

Forest Research, 2010. Benefits of Green Infrastructure, Farnham: Forest Research.

Extensive green roofs can reduce pollution compared to convetional roofs. They can reduce runoff by 45%, and also provide ecological services, being used by birds and invertebrates.

(5)

Glass, C.C., 2007. Green Roof Water Quality and Quantity Monitoring,

(6)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B., Woods Ballard, B. (2015) The SUDS manual, CIRIA. London.

Intensive green roofs require maintenance and are usually accessible. They provide good contribution to thermal performance of buildings, as well as good water retention capacity. Pollution removal is variable.

Can provide great amenity benefits.

(7)

Lamera, C. et al., 2013. Green roof impact on the hydrological cycle components. In EGU 10th General Assembly. p. 8038.

(8)

Lehmann, S., 2014. Low carbon districts: Mitigating the urban heat island with green roof infrastructure. City, Culture and Society, 5(1), pp.1–8

(9)

Liu, K.K.Y. & Baskaran, B., 2003. Thermal performance of green roofs through field evaluation, Ottawa.

(10) Mentens, J., Raes, D. & Hermy, M., 2006. Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century? Landscape and Urban Planning, 77(3), pp.217–226.

(11) Oberndorfer, E., Lundholm, J., Bass, B., Coffmann, R. R., Doshi, H., Dunnett, N., Gaffin, S., Koehler, M., Liu, K. K. Y. and Rowe, B. (2007) ‘Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services’, BioScience. Oxford University Press, 57(10), p. 823.

(12) Red Rose Forest, 2014. University of Manchester Green Roof - Green Wall Policy and Guidance, Manchester.

(13) Rowe, D.B., 2011. Green roofs as a means of pollution abatement. Environmental pollution, 159(8-9), pp.2100–10.

Comprehensive literature review of peer reviewed English language literature. Up to 0.5kg of PM/m2 are removed by grassed green roofs. Intensive roofs reduce even more – vegetation plays a key role. They can also sequester carbon, however their construction is often more carbon intensive than those of conventional roofs.

Green roofs can effectively retain pollutants like heavy metals by up to 99%, however this depends on their age, time of year and magnitude of rainfall.

(14) Royal Haskoning DHV, 2012. Costs and Benefits of Sustainable Drainage Systems,

(15) Speak, A.F. et al., 2012. Urban particulate pollution reduction by four species of green roof vegetation in a UK city. Atmospheric Environment, 61, pp.283–293.

Green roofs can remove 0.425 (sedum roof) to 3.21g (grass) PM10/m2/a. Intensive roofs have higher impacts than extensive roofs.

(16) U.S. Environmental Protection Agency, 2008.

Green Roofs. In Reducing Urban Heat Islands: Compendium of Strategies. Wasington D.C.: U.S. Environmental Protection Agency.

Extensive green roofs reduce runoff by 50-75%.

Studies have shown up to 75% reduction in demand for cooling, and 10% for heating (both studies carried out in Canada). They improve air quality by removing pollutants, studies having shown a removal of 0.2kg of PM/m2/a. They can also reduce heavy metals in runoff by up to 95% and reduce peak runoff as well as total runoff by 50-100%.

(17) Wolch, J.R., Byrne, J. & Newell, J.P., 2014. Urban green space, public health, and environmental justice: The challenge of making cities “just green enough.” Landscape and Urban Planning, 125, pp.234–244.

(18) Wong, N. H., Tay, S. F., Wong, R., Ong, C. L. and Sia, A. (2003) ‘Life cycle cost analysis of rooftop gardens in Singapore’, Building and Environment, 38(3), pp. 499–509.

(19) Yang, J., Yu, Q. & Gong, P., 2008. Quantifying air pollution removal by green roofs in Chicago.

Atmospheric Environment, 42(31), pp.7266–7273.

(20) http://www.thegreenroofcentre.co.uk/green_roofs/ faq

(21) http://livingroofs.org/ (22) http://www.greenroofguide.co.uk/

37

PERMEABLE PAVEMENTS Permeable pavements are made of material that is itself impermeable to water but the material is laid so that space is provided where water can infiltrate into the underlying structure. They reduce peak flows and effects of pollution. They require no additional land take and are therefore highly valuable interventions in dense areas, especially because they are easily accepted by the community around. An aggregate subbase allows water quality improvements and attenuation of flows, while a geotextile layer improves pollutant removal and performance.

Benefits Wheel

Landscape context Permeable Paving provides source control and infiltration and can be combined with storage systems. They are the first stage the water passes through. Where runoff cannot be completely eliminated, conveyance to a storage area should be designed.

Shows the contribution of permeable pavements to the provision of ecosystem services. More detail on the next page.

Costs

Featured Case Study

27-40ÂŁ/m2 (high). Depends on whether replacement or new development and type of paving. No need for connection to sewer system (saves additional costs). If all costs are taken into account, they are lower than for traditional surfacing and drainage. (4, 7)

Maintenance 0.5-1ÂŁ/m3 of water stored/treated.

Brushing/vacuuming every 6 months to prevent the clogging and accumulation of metals in the top layers is likely necessary to maintain good water quality performance.

Clogging however is more an issue with porous than permeable pavements. Unlimited design life. (4,5, 7, 8, 14)

Permeable paving in parking area. Oregon, USA In 2004, Environmental Services paved three blocks of streets in the Westmoreland neighbourhood with permeable pavement that allows water to go through the street surface and into the ground.

It is the first use of this type of permeable paving material on a public street in Portland, although similar materials are used locally in parking lots and private driveways.

Different types of permeable paving were tested in Portland to compare their performance in reducing runoff. Permeable paving absorbed runoff 27% quicker than concrete and porous asphalt (60 inches per hour). It also provides aesthetic benefits More: https://www.portlandoregon.gov/bes/article/77074

Feasibility Industrial and Domestic. Retrofit possible. The type of pavement used depends on expected traffic load and aesthetic requirements. Only gentle slopes. Adjacent areas need to be stabilised to prevent sediment flow into the paved area. Sand or sediment input can happen especially during construction; contractors have to be made aware of this. (5, 7, 8, 14)

38

Social Benefits

Environmental Benefits

Health: Access. * Can be used in multifunctional areas but does not provide same benefits as greenspace. Can provide area for recreational use. (8,15, 14)

Water Quality. * Pollutant reductions are very high but can depend on maintenance. TSS reductions of >60% (58-94), motor oil, diesel and metals (20-99) can be (nearly) completely removed. N and P have varying degrees of removal, dependent on the design of the structure (below ground infiltration). (1, 2, 6, 10, 12)

Air Quality. Not given.

Habitat Provision. Not given.

Surface Water. * 40% more effective peak flow reduction than conventional pavements, other studies have found runoff reductions of up to 100%, treating the paved area and to an extent even runoff from adjacent areas. Runoff generation can be eliminated. (1, 2, 3, 6, 9, 10, 13, 14)

Climate Regulation. * Potential to mitigate UHI through evaporation and storage of water but this depends on various factors. If combined with other technologies (see below) may help to reduce emissions. (11, 12, 14)

Fluvial Flood. * Can provide flood prevention downstream by reducing runoff into rivers.

Low Flows. * Permeable pavements can potentially allow groundwater recharge and combined with rainwater harvesting reduce pressure on mains water. (8)

Cultural Benefits

Economic Benefits

Aesthetics. * May allow grass to grow, creating attractive green area where otherwise only paving would be present.

Depends on type of pavement used. (7,15)

Property Value. * Depending on type and quality may add value. (14)

Cultural Activities. Not given.

Flood Damage. * Taking up water from their own area and surrounding areas can help reduce the risk of flooding and the extent of flooding on a larger scale.

Additional Benefits and Potential Costs Water re-use potential –There is high potential of combination with RWH systems that allow using the water for non-potable uses. The combination with geothermal heat pumps (GHPs) enables re-use of water (e.g. for gardening) along with energy efficient heating/cooling of buildings. This of course depends on the site context but can provide sustainable heating without need for fossil fuels (therefore reducing emissions).

Multi-functionality – Paved surface enables safe and comfortable use for vehicles and pedestrians while allowing infiltration and benefitting vegetation, providing treatment and flow management. While it is not a greenspace itself, it can improve the accessibility of greenspaces by providing convenient, safe paths through existing green infrastructure that integrate well with the landscape.

No additional impacts

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

39

References: (1)

Ahiablame, L. M., Engel, B. A. and Chaubey, I. (2012) ‘Effectiveness of Low Impact Development Practices: Literature Review and Suggestions for Future Research’, Water, Air, & Soil Pollution, 223(7), pp. 4253–4273.

Studies show runoff reductions by 50-93%, with pollutant removal for various substances ranging from 20-99%(metals), 58-94%(TSS), 75-85%(N) and 10-78%(P). Runoff generation can be eliminated, PPS are therefore a valuable source control system.

(2)

Ashley, R. M., Nowell, R., Gersonius, B. and Walker, L. (2011) ‘Surface Water Management and Urban Green Infrastructure’, 44(0), pp. 1–76.

Woods Ballard, B. (2015) The SUDS manual, CIRIA. London.

(9)

Qin, H., Li, Z. & Fu, G., (2013). The effects of low impact development on urban flooding under different rainfall characteristics. Journal of environmental management, 129, pp.577–85.

Runoff reduction of 75% on average through permeable pavement. Best for smaller storms with short durations, with peaks in the middle of the event.

(10) Scholz, M. & Grabowiecki, P., (2007). Review of permeable pavement systems. Building Environment, 42(11), pp.3830–3836.

and

Permeable and porous pavements provide 10-42% more effective peak flow reduction compared to conventional asphalts. They provide good water quality treatment with TSS reductions of about 60% and nearly complete removal of motor oil, diesel and metals.

(3)

Booth, D.B. & Leavitt, J., (1999) Field Evaluation of Permeable Pavement Systems for Improved Stormwater Management. Journal of the American Planning Association, 65(3), pp.314–325.

(4)

Environment Agency (2015) Cost estimation for SUDS - summary of evidence. Bristol.

(11) Starke, P., Goebel, P. & Coldewey, W., (2010).

(5)

Harley, M. & Jenkins, C., (2014). Research to ascertain the proportion of block paving sales in England that are permeable, Report for the SubCommittee of the Committee on Climate Change.

(12) Tota‐Maharaj, K. et al., (2010). The synergy of

Imran, H.M., Akib, S. & Karim, M.R., (2013).

Permeable pavement and stormwater management systems: a review. Environmental technology, 34(1720), pp.2649–56.

(13) U.S. Environmental Protection Agency (2013).

(6)

(7)

Interpave, (2008). Understanding Permeable Paving, Leicester.

Design guidance and description of various available systems and performances.

(8)

Kellagher, R., Martin, P., Jefferies, C., Bray, R., Shaffer, P., Wallingford, H. R., Woods-Ballard, B.,

Urban evaporation rates for water-permeable pavements. Water Sci Technol, 62(5), pp.1161–9. permeable pavements and geothermal heat pumps for stormwater treatment and reuse. Environmental Technology, 31 (14), pp. 1517-31.

Stormwater to Street Trees. Washington: USEPA.

(14) Royal Horticultural Society (2016): Front gardens: permeable paving.

(15) http://www.susdrain.org/delivering-suds/using-

suds/suds-components/source-control/pervioussurfaces/pervious-surfaces-overview.html

40

RAINWATER HARVESTING/WATER BUTTS By collecting water from impermeable surfaces, rainwater harvesting can reduce the volume of runoff and peak flows and so have a positive impact on surface water flooding. It can vary in scale from single water butts installed on private properties to underground storage tanks on commercial areas. Costs and effectiveness of the intervention depend on its scale and design, but benefits from reduced runoff are only significant for larger systems.

Benefits Wheel

Landscape context Rainwater Harvesting acts as source control and storage.

It prevents runoff by taking it up at its source. In one year, it is estimated that 24,000l can on average be saved from a roof in the UK, preventing this additional runoff.

Once RWH systems have reached their capacity, they cannot contribute any more to reducing runoff. Ways of dealing with overflows have to be incorporated – this could be infiltration systems like Rain Gardens, for example, taking up water spilling out of water butt outlets.

The impact of RWH is mostly realised on a local scale, but cumulative effects where RWH is implemented on as many properties as possible are to be expected.

Shows the contribution of rainwater harvesting to the provision of ecosystem services. More detail on the next page.

Costs

Featured Case Study

£10+ for water butts, £2000-4000 for a complete domestic system. Retrofit is possible but likely more expensive for entire systems. Depends on scale and type of the system (e.g. gravity fed or pump system) and existing connections.

Maintenance Costs: £0.1-0.4 per m2 (4,7) Typical maintenance activities: cleaning and inspection. Depends on context and type of system.

Rainwater Harvesting at Calke Abbey, National Trust With total costs of £11,181.86, the National Trust installed a Rainwater Harvesting System on its property in Calke Abbey to reduce pressures on mains water and make use of the relatively high volumes of rainfall. Estimated savings from mains water use are £625 per year at the moment, and the harvested rainwater is now the main supply for garden irrigation where previously mains water was used.

More: https://www.nationaltrust.org.uk/calkeabbey/documents/calke-abbey---building-design-guide.pdf

Feasibility Context: Residential, Industrial. Retrofit and use in high density urban areas possible.

Connection to rainwater pipes is necessary. More water is collected from sloping roofs. (7)

41

Social Benefits

Environmental Benefits

Health: Access. * Rainwater Harvesting Systems provide no access to or to the benefits of accessing green space.

Water Quality. * Rainwater Harvesting provides no opportunity for reducing pollution and may even deteriorate the quality of water. However, it does intercept water initially and can so reduce the first flush effect.(2,5)

Air Quality. * Rainwater Harvesting Systems have no impact on air quality.

Habitat Provision. * Rainwater Harvesting Systems have no capacity to provide habitats for wildlife.

Surface Water. * High peak flow and volume reductions can be achieved depending on the size and design of the system/butt and the saturation of the system. An estimated 24,000l/a can be saved from the average roof (11). However, there is little evidence on the scale of this impact on flooding.

(1,3,8)

Climate Regulation. * Rainwater harvesting can have positive impacts by saving water and thus energy, but if pumps are used the emissions might outweigh the benefits. (3,6)

Fluvial Flood. * Rainwater Harvesting systems are unlikely to contribute to reducing fluvial flooding apart from reducing runoff into water courses.

Low Flows. * RWH can indirectly reduce abstraction rates by reducing demands on mains water (up to 80% of mains water use in industrial/commercial buildings, 30-50 in domestic) (12).

However, there are few studies on the scale of this impact.

Cultural Benefits

Economic Benefits

Aesthetics. * Water butts can be used as planters and so provide aesthetic benefits. Tanks can be stored underground so as to not impact on the landscape or be designed to provide amenity value. (8, 10)

Property Value. * Rainwater Harvesting Systems may be able to add value to a property, especially if they are extensive.

Cultural Activities. * Rainwater Harvesting Systems provide no opportunity for cultural activities or further cultural benefits.

Flood Damage. * Due to their impact on surface water flooding, Rainwater Harvesting Systems may influence the extent of flooding downstream.

Additional Benefits and Potential Costs Economic. Even if there is no increase in property value, rainwater harvesting systems and water butts can save significant amounts on water bills (depending on type of water use and intensity of use).

Water re-use. During periods of hosepipe bans, as they can happen more frequently, harvested rainwater can be used to water vegetation and keep it beautiful. For bigger systems, the ability to meet water demand independent of mains water can provide sustainability and resilience benefits.

Energy use. Where complete RWH systems are installed with pumps, the intensity of energy use can be increased compared to mains water. This can have net negative impacts on emissions from the system. This is not the case for water butts and other storage systems without pumps.

Water quality. While it is generally not an issue, water harvested from roofs can hold high concentrations of pollutants, especially after long dry periods. However, there is little evidence of this occurring in significant frequency. It is important to connect drain pipes correctly, so only rainwater is discharged into the water storage

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

42

References: (1)

Ashley, R. M., Nowell, R., Gersonius, B., & Walker, L. (2011). Surface Water Management and Urban Green Infrastructure, 44(0), 1–76.

(2)

Berwick, N., & Wade, D. R. (2013). A Critical Review of Urban Diffuse Pollution Control : Methodologies to Identify Sources , Pathways and Mitigation Measures with Multiple Benefits.

(3)

CIRIA. (2014). Demonstrating the multiple benefits of SuDS - a business case.

(4)

Environment Agency. (2015). Cost estimation for SUDS - summary of evidence. Bristol.

(5)

Helmreich, B., & Horn, H. (2009). Opportunities in rainwater harvesting. Desalination, 248(1-3), 118– 124.

(6)

Parkes, C., Kershaw, H,, Hart, J. Sibille, R., Grant, Z (2010):Energy and carbon implications of rainwater harvesting and greywater recycling.

Bristol: Environment Agency.

(7)

Woods Ballard, B., Wilson, S., Udale-Clarke, H., Illman, S., Ahsley, R., Kellagher, R. (2015): The Suds Manual. London: CIRIA.

(8)

Susdrain (2016): http://www.susdrain.org/delivering-suds/usingsuds/suds-components/source-control/rainwaterharvesting.html

(9)

Savetherain.info http://www.savetherain.info/mediacentre/rainwater-harvesting-faa qs.aspx

(2016):

(10) Rainwaterharvesting

Ltd (2016): http://www.rainwaterharvesting.co.uk/rainwaterhar vesting-simple-guide.php

(11) BBC

(2016) http://www.bbc.co.uk/gardening/basics/techniques/ watering_savingwater1.shtml

(12) YouGen.co.uk (2016), Rain harvesting http://www.yougen.co.uk/energysaving/Rain+Harvesting/.

43

EXISTING GREEN & BLUE INFRASTRUCTURE Image: Craig Boney (CC BY-NC-ND 2.0)

44

PUBLIC PARKS AND GARDENS Public Parks and Gardens are important existing assets of an urban environment, with 91% of people in the UK believing that public parks and open spaces improve their quality of life (4). While high land prices and pressure from different competing objectives often makes the development of a new park in an area unlikely (although not impossible – see for example the Thames Barrier Park Case study) it is all the more important to protect existing parks and manage them in a way that maximises the multiple benefits laid out below. Benefits from parks, as far as they have been monetised, are significant: Edinburgh, for example, has shown that its public parks show a SROI of on average £12 for every £1 invested, and Camley Street Park (London) alone has calculated a total of £2.8 million in ecosystem service benefits per year.

Benefits Wheel

Landscape context Parks have recorded increasing visitor numbers, showing that there is a demand for their use. Over 10% of people visit or pass through their local parks daily, and over 50% at least once per month. Especially for parents and households with children, parks are a significant resource, socially as well as culturally, with over 80% of people with children under 10 in the household using their local park at least monthly. Parks and open space have been suggested to be the third most frequently used public service after GP surgeries and hospitals. However, budgets are being cut and staff numbers reduced, leading to increased user charges and potential deterioration of their condition.

Shows the contribution of parks to the provision of ecosystem services.

More detail on the next page.

Parks – depending on their size and design – often constitute a combination of different types of green infrastructure type ‘interventions’ and their value to society and the environment depends on their different parts. To understand what different singular ‘modules’ in a park do (e.g. trees, ponds), or how these could be incorporated, please refer to additional factsheets. Parks have the additional benefit of bringing all these single modules together and potentially achieving an effect that is larger than the sum of its parts. (4, 8).

Maintenance Costs Average management costs of parks in 2013/14: £6,410/ha. (8) Often maintenance activities are already carried out by volunteer groups and this can provide a valuable opportunity to protect existing parks with the additional social benefits that volunteer groups provide.

Featured Case Study

Camley Street Natural Park Camley Street Natural Park now provides access to nature in a densely populated area. It contains a pond, a meadow, a marsh and woodland providing a habitat for a variety of wildlife.

The natural park has been managed by London Wildlife Trust since its opening, on behalf of London Borough of Camden. Some of the benefits are: Habitat provision (70 species of trees, 32 species of bees, 20 species of amphibians and reptiles, 75 species of birds, 8 species of fish), regulating noise, providing educational space, enabling access to nature (with 15,000-20,000 visitors each year).

Total ecosystem service value: £2.8 million per year. http://www.atkinsglobal.co.uk/~/media/Files/A/AtkinsCorporate/group/cs/Camley-st-natural-park.pdf Image: www.wildlondon.org.uk

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Social Benefits

Environmental Benefits

Health: Access. * A greater quantity of urban green space is generally associated with better health. The “healthiest” areas in England (i.e. with the higher levels of activity and lowest levels of obesity) have 20% higher green spaces than the least healthy areas. Being exposed to park settings has also been linked to better attention performance, reduced cardiovascular morbidity in males and better recovery rates.

However, even though a lot of evidence points to this positive link, there are diverse results in the literature – which possibly points to the importance of park design in enabling the provision of benefits. (2,4,5,6,9,10,12,13,14,20)

Water Quality. * Through water infiltration, parks can prevent pollutants from reaching waterbodies and streams.

Fertilization and pesticide use however can have a negative impact. (2, 16, 18)

Air Quality. * While research focusing on parks specifically is limited, it is clear that trees have a big impact on air quality.

Air quality within parks is often better than outside, as are air temperatures. This is true for PM10 but also other pollutants like NOx and SOx. (2, 6, 10, 18, 20)

Surface Water. * Due to high infiltration rates, grassed areas are able to nearly completely eliminate runoff, therefore having a positive impact on surface water flooding. In Manchester areas with less green space are more susceptible to surface water flooding. The effect however depends on type of vegetation and intensity/duration or rainfall as well as factors like soil type and compaction. (2, 9, 15, 16, 18)

Fluvial Flood. * To an extent, parks can provide flood storage if they are designed to do so, and this should be taken into account when designing new parks as well as when existing ones are restored or redeveloped. (18)

Cultural Benefits

Habitat Provision. * Often, parks have been found to be the most biodiverse type of urban of green space. However, this can be due to exotic species. Larger, more diverse and less isolated parks harbour more native species. (2,3, 16, 17, 20, 22)

Climate Regulation. * Parks, especially those with high tree cover, can act as carbon sinks. A study in Leicester has shown that 97.3% of the carbon pool stored in urban vegetation is stored in trees. Parks provide resilience against increasing temperatures and the UHI effect. Air temperatures in London have been shown to be 2-8 degrees lower in greenspaces. This could mean that the current provision on green space in London saves 16-22 lives per day during heatwaves. Parks can influence the air quality in surrounding areas as the temperature difference can lead to “park breeze” into surrounding built up areas. (1,2, 6, 7, 9, 18, 20)

Low Flows. * Parks have been shown to contribute significantly to groundwater recharge due to their high infiltration rates (over 30%). Grassed areas are able to nearly completely eliminate runoff. (9,16)

Economic Benefits

Aesthetics. * The aesthetic value of parks can be very high and is for example shown through their impact on property values as well as stress and mental fatigue. A study in Zurich found parks and urban forests to be associated with an 87% recovery ration for stress and 40% enhancement of positive feelings. Some studies show these benefits even from just viewing green space (2, 19)

Property Value. * There are wide ranges between different cities and countries but parks almost always have a positive impact on property values. While park size is a factor, even small parks can have an impact. (e.g. a study in the Netherlands has shown an increase in 5-12% for houses overlooking attractive areas, and 6-12% for houses overlooking open spaces) (2, 11, 18, 20)

Cultural Activities. * Many parks provide venues for annual festivals, meeting spaces for community groups and therefore add to the cultural service provision in an area.

Parks, as accessible local green spaces, can give rise to cultural activities like bird watching, painting or photography. (2,4, 6, 20)

Flood Damage. * Due to their impact on surface water and their potential contribution to mitigating fluvial flooding, parks can reduce severity of flooding and the damage caused by it.

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Additional Benefits and Potential Costs Crime: Higher levels of high quality green space provision are correlated with lower crimes. Apart from the economic benefits, this means a positive impact on the community and the mental wellbeing of residents. Studies in the US have shown more than 25% reduced crime rates and aggressive behaviour in areas with green space provision than in those with less. This seems to be due to the environment deterring criminal activity by increasing use of the space and natural surveillance, but also to green space preventing mental fatigue. (4,9, 21)

Crime: Poor quality green space can actually enforce antisocial behaviour. Parks that are not maintained well can become hotspots for crime and vandalism, and lead to perceptions of unsafety.

Property value: As with crime, poor quality green space can actually have the reverse effect of what it is meant to achieve and reduce values of properties where it is perceived to be an unsafe area.

Local Economy: Small businesses are more likely to settle in areas with good parks, open spaces and recreational areas.

Visitor spending has been shown to be higher in attractive areas, and while this is not specific to parks, they are often connected to shopping trips in one way or another. (9, 18) Mental health Parks provide important mental health benefits by offering somewhere to escape from daily life, exercise and build a connection with nature. 30% lower depression rates in areas with higher greenspace have been shown. Biodiversity has also been shown to impact on the psychological benefit of visiting parks, with the species richness being more important than the area of the green space. A study in Bristol has shown that children are more likely to engage in active play in areas with green spaces. A study in Greenwich showed that dissatisfaction with urban green space is related to poor mental health. (4, 8, 9) Social Cohesion: A study in Vienna has shown an increased “attachment” to an area in places with a perceived higher supply and quality of greenspace. There is evidence showing that particularly if teenagers are catered for with specific facilities and equipment, parks have the potential to cater for multiple ethnic groups, potentially improving social cohesion in the neighbourhood. (4,9,20) *** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

References: (1)

Armson, D., P. Stringer, and A.R. Ennos. 2012.

“The Effect of Tree Shade and Grass on Surface and Globe Temperatures in an Urban Area.”

Urban Forestry & Urban Greening 11 (3): 245–55.

(2)

BOP Consulting. 2013. “Green Spaces: The Benefits for London.”

(3)

Chamberlain, D.E., S. Gough, H. Vaughan, J.A. Vickery, and G.F. Appleton. 2007. “Determinants of Bird Species Richness in Public Green Spaces: Capsule Bird Species Richness Showed Consistent Positive Correlations with Site Area and Rough Grass.” Bird Study 54 (1). Taylor & Francis Group: 87–97.

(4)

(5)

Commission for Architecture and the Built Environment. 2005. “Decent Parks? Decent Behaviour? The Link between the Quality of Parks and User Behaviour” 1–17.

Coombes, Emma, Andrew P Jones, and Melvyn Hillsdon. 2010. “The Relationship of Physical Activity and Overweight to Objectively Measured Green Space Accessibility and Use.” Social Science & Medicine (1982) 70 (6): 816–22.

(6)

Faculty of Public Health. 2010. “Great Outdoors: How Our Natural Health Service Uses Green Space To Improve Wellbeing”.

(7)

Forestry Commission. 2013. “Air Temperature Regulation by Urban Trees and Green Infrastructure.” Farnham.

(8)

Heritage Lottery Fund. 2014. “State of UK Public Parks.” London.

(9)

Konijnendijk, Cecil C, Matilda Annerstedt, Anders Busse Nielsen, and Sreetheran Maruthaveeran.

2013. “Benefits of Urban Parks. A Systematic Review.” Copenhagen&Alnarp.

(10) Lovasi, G S, J W Quinn, K M Neckerman, M S Perzanowski, and A Rundle. 2008. “Children Living in Areas with More Street Trees Have Lower Prevalence of Asthma.” Journal of Epidemiology and Community Health 62 (7): 647–49.

(11) Luttik, Joke. 2000. “The Value of Trees, Water and Open Space as Reflected by House Prices in the Netherlands.” Landscape and Urban Planning 48 (3-4): 161–67.

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(12) McCormack, Gavin R, Melanie Rock, Ann M Toohey, and Danica Hignell. 2010. “Characteristics of Urban Parks Associated with Park Use and Physical Activity: A Review of Qualitative Research.” Health & Place 16 (4): 712–26.

(13) Mitchell, Richard, and Frank Popham. 2007.

“Greenspace, Urbanity and Health: Relationships in England.” Journal of Epidemiology and Community Health 61 (8): 681–83.

(14) Richardson, Elizabeth A, and Richard Mitchell.

2010. “Gender Differences in Relationships between Urban Green Space and Health in the United Kingdom.” Social Science & Medicine (1982) 71 (3): 568–75.

(15) Rogers, K., Jaluzot, A. and Neilan, C. (2011) Green

2014. “The Influence of Urban Green Environments on Stress Relief Measures: A Field Experiment.” Journal of Environmental Psychology 38 (June): 1–9.

(20) Woolley, Helen, Sian Rose, Matthew Carmona, and Jonathan Freedman. 2004. “The Value of Public Space.” Exchange Organizational Behavior Teaching Journal. London.

(21) Kuo, F. E. and Sullivan, W. C. (2001) ‘Environment and Crime in the Inner City: Does Vegetation Reduce Crime?’, Environment and Behavior, 33(3), pp. 343–367.

(22) Forestry Commission. Benefits of Greenspace: Park and Garden Habitats. http://www.forestry.gov.uk/fr/urgc-7edjrw

Benefits in Victoria Business Improvement District.

(16) Speak, A. F., Mizgajski, A. and Borysiak, J. (2015)

Web references and useful weblinks:

‘Allotment gardens and parks: Provision of ecosystem services with an emphasis on biodiversity’, Urban Forestry & Urban Greening, 14(4), pp. 772–781.

American Planning Association: How Cities Use Parks for Green Infrastructure, Briefing Paper. https://www.planning.org/cityparks/briefingpapers/greeni nfrastructure.htm

(17) Stagoll, Karen, David B. Lindenmayer, Emma

National Recreation and Park Association: Pocket Parks https://www.nrpa.org/uploadedFiles/nrpaorg/Grants_and _Partners/Recreation_and_Health/Resources/Issue_Brie fs/Pocket-Parks.pdf

Knight, Joern Fischer, and Adrian D. Manning.

2012. “Large Trees Are Keystone Structures in Urban Parks.” Conservation Letters 5 (2): 115–22.

(18) Sunderland, T. 2012. “Microeconomic Evidence for the Benefits of Investment in the Environment Review.” Natural England Research Reports, Number 033. Vol. 2.

(19) Tyrväinen, Liisa, Ann Ojala, Kalevi Korpela, Timo Lanki, Yuko Tsunetsugu, and Takahide Kagawa.

Forest Research: Greenspace initiatives. Urban Parks and Gardens: http://www.forestry.gov.uk/fr/urgc-7ekebr Greenspace Scotland.: http://greenspacescotland.org.uk/ Big Lottery Fund. Parks for People Funding: https://www.biglotteryfund.org.uk/prog_parks_people.

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COMMUNITY GARDENS & ALLOTMENTS Orchards and allotments show similar benefits to parks and other open areas regarding their environmental and partly social benefit, as they are comprised of similar structural elements (trees, shrubs, meadow like areas) and therefore exhibit similar properties in terms of infiltration and water quality. However, what makes these types of urban green spaces unique is the social and cultural aspect of food production and land ownership in an otherwise urban environment. The ecosystem services provided depend on how the allotments/orchards are used and guidance for allotment owners and users should be considered within the management of surface water and multiple ecosystem services.

Benefits Wheel

Landscape context The high land take of allotments makes them unlikely to be used on a large scale. As they cover a significant amount of land, they have the potential to contribute locally not only by infiltrating runoff and providing amenity benefits but also provide the opportunity to incorporate other interventions – e.g ponds, swales – within them, maximising multiple benefits.

As they are not accessible to the public, certain benefits – access, social cohesion, education, … - can only be provided on a fairly limited scale. However, this is likely to benefit particularly older demographics, which can be an important aspect.

Shows the contribution of allotments to the provision of ecosystem services. More detail on the next page.

Costs

Featured Case Study

The cost of allotments or orchards are hard to estimate and are more dependent on the opportunity costs from lost opportunities for housing/ commercial develop-ment. Users of allotments pay for accessing the space, with fees varying in different areas but on average between £30-£40 for a 250m2 plot (2).

Maintenance As allotments are managed privately, maintenance costs depend on the individual owner. Avoiding soil compaction, planting and maintaining buffer strips and allowing wild habitat can maximise provision of ecosystem services

‘The social, health and wellbeing benefits of allotments: five societies in Newcastle’ (Ferres, M. and Townshend, T. G., 2012) Three main reasons for having an allotment were identified: (1) Being able to grow one’s food, (2) the enjoyment and pleasure obtained by the activity itself, (3) dedicating time to relaxation and exercise.

This demonstrates psychological, physical and social benefits, with allotment holders saying that contact with nature at the allotments is an important factor in their lives. 79% of participants state they obtain psychological or spiritual benefits from having an allotment and 72% state they gain physical benefits.

More: http://www.ncl.ac.uk/guru/documents/EWP47.pdf

Feasibility The main factor determining the feasibility of allotments is the availability of suitable land. Demand is usually given, with many allotments having waiting lists for plots. Opportunities for new creation are undeveloped land or reclaiming of previous allotment sites, as well as protection of existing sites

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Social Benefits

Environmental Benefits

Health: Access. * While allotments are not freely accessible, they provide significant health benefits to a wide number of people, especially in an older age group. They provide an important space to form community ties and social cohesion.

(3,5,6,7)

Water Quality. * Bioretention can improve water quality in many aspects, and it is likely that similar processes occur in allotment soils. Water and with it pollutants are captured by existing vegetation this can be increased by installing filter and buffer strips in runoff pathways. (3,4,16)

Air Quality. * Air quality is not a significant benefit provided by allotments, hover they can have an impact on a regional scale, with trees being able to filter pollutants. Orchards are likely to have a more significant impact. (3,13)

Habitat Provision. * Allotments and orchards can provide great habitats for pollinators and other insects as well as mammals, birds and amphibians etc. More plant species have been found in allotments than in parks in a study in Manchester, although no rare species were found.(2,3)

Surface Water. * Open surfaces allow infiltration and can increase groundwater recharge, therefore improving low flow conditions. Infiltration on vegetated areas is 20%+ higher than on impermeable ground, and grassed areas have been shown to have the potential to nearly completely eliminate runoff.

(3,4,15,16,17,18)

Climate Regulation. * Allotments and orchards provide mitigation of the UHI effect by lowering air temperatures and allowing influx of fresh air, and store carbon in vegetation and soils. This benefit is likely to be greater from orchards.

(3,14)

Fluvial Flood. * Allotments can only contribute to reducing fluvial flood risk by infiltrating water before it reaches streams.

(17)

Low Flows. * Infiltration can enable groundwater recharge and so have a positive impact on low flows.

Cultural Benefits

Economic Benefits

Aesthetics. * The aesthetic quality of a site is the second most important aspect in choosing an allotment site, it can therefore be inferred that they generate significant aesthetic benefits.(6,7)

Property Value. * Attractive views of green spaces have been shown to increase property values by 10+%, however there is no specific literature on the effect of allotments. (19)

Cultural Activities. * Growing food is an – in urban environments rare - cultural and educational activity and allotments are often used to experiment with exotic as well as native species. (5,6,7,8,9,10)

Flood Damage. * By reducing the impermeability of an urban area, allotments can help to reduce severity of floods.(17)

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Additional Benefits and Potential Costs Mental Health. Allotments have been shown to generate a sense of pride, engagement with nature and an increased well-being is reported by 80% of allotment gardeners. They are especially important as community resources and generate multi-cultural meeting spaces.

Water Quality. The use of pesticides and fertilizer can have a negative impact on the water quality of receiving systems.

Organic fertilizer and pest control through natural mechanisms (e.g. providing habitat for natural predators) should be encouraged.

Food Production. People who own an allotment eat more fresh fruit and vegetables than those who 0don’t. A study in Manchester has quantified the economic benefit of food production on allotments to be on average 698£ per plot and year (3). Another report has found the total food production in London in urban gardens to be £1.4 million per year.

Flooding. Allowing runoff to collect in allotments is only viable as long as the area does not suffer from permanent waterlogging. Hydraulic connectivity should be as high as possible, and structures increasing infiltration – e.g. trees or infiltration trenches – as well as storage structures like ponds should be incorporated.

*** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

References: General/Guidance: (1)

Environment Strategy Unit Chichester District Council (no date) A Guide to Setting up and Managing a Community Orchard.

(2)

Natural England (2007). Wildlife on Allotments.

This document gives guidance on obtaining an allotment and making it a valuable resource for wildlife, advising that prizes for a plot of 250m2 are on average between £30 and 40, but can be much higher in dense areas. The habitat can be enhanced by installing nesting boxes, hedgerows, ponds or similar, and the report gives further guidance on what plants to use and how to manage a plot in order to encourage biodiversity.

(3)

Social Benefits: (5)

Ashley, R. M., Nowell, R., Gersonius, B. and Walker, L. (2011) ‘Surface Water Management and Urban Green Infrastructure’, 44(0), pp. 1–76.

van den Berg, A. E., van Winsum-Westra, M., de Vries, S. and van Dillen, S. M. E. (2010) ‘Allotment gardening and health: a comparative survey among allotment gardeners and their neighbors without an allotment.’, Environmental health : a global access science source, 9, p. 74.

After adjusting for income, education level, gender, stressful life events, physical activity in winter, and access to a garden at home as covariates, both younger and older allotment gardeners reported higher levels of physical activity during the summer than neighbors in corresponding age categories. The impacts of allotment gardening on health and well-being were moderated by age. Allotment gardeners of 62 years and older scored significantly or marginally better on all measures of health and well-being than neighbors in the same age category. Health and well-being of younger allotment gardeners did not differ from younger neighbors. The greater health and well-being benefits of allotment gardening for older gardeners may be related to the finding that older allotment gardeners were more oriented towards gardening and being active, and less towards passive relaxation.

Speak, A. F., Mizgajski, A. and Borysiak, J. (2015) ‘Allotment gardens and parks: Provision of ecosystem services with an emphasis on biodiversity’, Urban Forestry & Urban Greening, 14(4), pp. 772–781.

This study is an attempt to assess and compare the ecosystem services provided by AGs in Manchester, UK, and Poznań, Poland as well as a comparison to city parks. The results of this study show that AGs can be highly species-rich environments and may offer a method of food production that does not incur as many trade-offs with biodiversity as other land uses.

The study also shows that the highest potential for benefits arises from provisioning and cultural services, e.g. generating knowledge, recreation, food production and genetic resources. It is worth noting that many of the additional ecosystem services beyond food production, provided by AGs, have spatial impacts beyond the confines of the gardens. Local climate regulation, flood protection and air quality regulation will especially benefit a large number of local residents in cities at the neighbourhood scale.

(4)

This report investigates the benefits of urban green infrastructure, specifically with regards to the management of surface water quantity and quality.

(6)

Ferres, M. and Townshend, T. G. (2012) ‘The social, health and wellbeing benefits of allotments: five societies in Newcastle’, School of Architecture, Planning and Landscape, 47, pp. 1– 47.

This report investigates the benefits of having an allotment for residents of Newcastle. It seeks to fill a gap in the knowledge around why people choose to maintain an allotment. Three main reasons were identified: growing one’s own food, enjoyment of the activity itself, and dedicating time to relaxation and exercise. In the study, 79% of participants state they obtain psychological or spiritual benefits from having an allotment and 72% state they gain physical

51 benefits. However, allotment holders also have concerns regarding the future of the allotments in Newcastle, with many people saying that the biggest threat comes from development pressure by local councils.

(7)

Ferris, J., Norman, C. and Sempik, J. (2001) ‘People, Land and Sustainability: Community Gardens and the Social Dimension of Sustainable Development’, Social Policy & Administration, 35(5), pp. 559–568.

Community gardens vary enormously in what they offer, according to local needs and circumstance. This article reports on research and experience from the USA. The context in which these findings are discussed is the implementation of Local Agenda 21 and sustainable development policies. In particular, emphasis is given to exploring the social dimension of sustainable development policies by linking issues of health, education, community development and food security with the use of green space in towns and cities. The article concludes that the use of urban open spaces for parks and gardens is closely associated with environmental justice and equity.

(8)

Glover, T. D., Parry, D. C., & Shinew, K. J. (2005).

Building relationships, accessing resources: Mobilizing social capital in community garden contexts. Journal of Leisure Research, 37(4), 450474.

This paper explores the role of social capital and formation of relationships in the context of community gardening. CG are presented as settings for building social networks and a knowledge base and can therefore provide important social and cultural benefits.

(9)

Flachs, A. (2010) ‘Food For Thought: The Social Impact of Community Gardens in the Greater Cleveland Area’, Electronic Green Journal, 1(30).

This paper explores the social and cultural effects of urban gardening in the greater Cleveland area.

Gardening is shown to have a multitude of motivating factors, including economic, environmental, political, social, and nutritional.

(10) Joe Howe (2002) Planning for Urban Food: The Experience of Two UK Cities, Planning Practice & Research, 17:2, 125-144 This article puts urban food growing in the context of the Agenda21 and discusses the role of allotments in urban policy and sustainability. It finds multiple important drivers in using an allotment, and pressures on their development and use.

(11) Woolley, H., Rose, S., Carmona, M. and Freedman, J. (2004) The Value of Public Space, Exchange Organizational Behavior Teaching Journal. London.

This report mentions especially the social benefits of allotment and community gardens as benefits gained from this type of public space. Allotments have for example been shown to encourage cross-cultural community ties.

(12) Sustain

(2014).

Reaping Rewards.

Can Communities Grow a Million Meals for London?

Based on this analysis, and knowledge of the types and sizes of food growing spaces throughout the 2,200+ membership of the Capital Growth network, this report estimates that London's community food growers could be growing as much as £1.4 million worth of food over the course of a year.

(13) Forest Research (no date) Improving Air Quality.

(14) Forestry Commission (20130. Air Temperature Regulation by Urban Trees and Green Infrastructure. Farnham.

Surface Water Management (15) Armson, D., Stringer, P. and Ennos, A. R. (2013) ‘The effect of street trees and amenity grass on urban surface water runoff in Manchester, UK’, Urban Forestry & Urban Greening, 12(3), pp. 282– 286. doi: 10.1016/j.ufug.2013.04.001.

This study assessed the impact of trees upon urban surface water runoff by measuring the runoff from 9m2 plots covered by grass, asphalt, and asphalt with a tree planted in the centre. It was found that, while grass almost totally eliminated surface runoff, trees and their associated tree pits, reduced runoff from asphalt by as much as 62%.

(16) Davis, A. P., Shokouhian, M., Sharma, H. and Minami, C. (2001) ‘Laboratory study of biological retention for urban stormwater management.’, Water environment research : a research publication of the Water Environment Federation, 73(1), pp. 5–14.

Urban stormwater runoff contains a broad range of pollutants that are transported to natural water systems. A practice known as biological retention (bioretention) has been suggested to manage stormwater runoff from small, developed areas.

Bioretention facilities consist of porous soil, a topping layer of hardwood mulch, and a variety of different plant species. Reductions in concentrations of all metals were excellent (> 90%) with specific metal removals of 15 to 145 mg/m2 per event. Moderate reductions of TKN, ammonium, and phosphorus levels were found (60 to 80%).

(17) Perry, T. and Nawaz, R. (2008) ‘An investigation into the extent and impacts of hard surfacing of domestic gardens in an area of Leeds, United Kingdom’, Landscape and Urban Planning, 86(1), pp.

1–13. doi: 10.1016/j.landurbplan.2007.12.004.

A study in Leeds has linked the increase in paved front gardens (and therefore increase in impermeable area) to an increased severity in surface water flooding in that area. A 13% increase in paved area was observed over 33 years, of which 75% is due to paving of front gardens, that lead to a predicted 12% increase of average surface water runoff. This prediction was reflected by actual events in Leeds, where heavy rainfall led to more frequent and severe flooding.

(18) Yao, L., Chen, L., Wei, W. and Sun, R. (2015) ‘Potential reduction in urban runoff by green spaces in Beijing: A scenario analysis’, Urban Forestry & Urban Greening, 14(2), pp. 300–308.

52 The results show that urban green space offers significant potential for runoff mitigation. In 2012, a total of 97.9 million m3 of excess surface runoff was retained by urban green space; adding nearly 11% more tree canopy was projected to increase runoff retention by >30%, contributing to considerable benefits of urban rainwater regulation. At a more detailed scale, there were apparent internal variations.

Urban function zones with >70% developed land showed less mitigation of runoff, while green zones (vegetation >60%), which occupied only 15.54% of the total area, contributed 31.07% of runoff reduction.

(19) Luttik, Joke. 2000. “The Value of Trees, Water and Open Space as Reflected by House Prices in the Netherlands.” Landscape and Urban Planning 48 (3-4): 161–67. http://www.nsalg.org.uk/ https://www.cambridge.gov.uk/content/benefitsallotment http://greenspacescotland.org.uk/our-growingcommunity.aspx http://www.allotment-garden.org/

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URBAN RIVERS Rivers have in many cases provided the resources and benefits necessary for the development of cities. Yet, in urban areas, rivers have often been seen as a threat to infrastructure and human health rather than as a resource, leading to their increasing degradation. Many benefits that arise from protecting rivers and restoration projects can be similar to those from public parks where access is given and the restoration is designed to provide a similar environment, it can therefore be useful to refer to this factsheet to understand further benefits. Opportunities for river restoration in parks and other open spaces may also be more easily found than in higher density urban environments.

Benefits Wheel

Landscape context Rivers receive water as runoff from their surroundings, even more so due to the increasing impermeability of the urban environment. Sewers – meant to carry surface water flow, but often also carrying pollutants from misconnections – also discharge into watercourses. In addition, other pressures are present in the urban environment: air pollution from traffic can cause acidification. Pesticides from roadsides or amenity areas can reach the water, as well as fertilisers. Construction sites can cause high sediment inflow. (Environment Agency 2009). Past culverting and straightening streams and disconnecting them from floodplains has also had a degrading impact.

These pressures threaten the quality of rivers and their value as habitats, but also the benefits they can bring to people, some of which are represented in the benefits wheel on the left, and explained in more detail on the next page..

Shows the contribution of rivers to the provision of ecosystem services.

More detail on the next page.

Maintenance Costs To improve the state of urban rivers and restore the benefits they provide, there are many interventions that can be taken. Habitat can be restored, for example by removing hard riverbanks and re-meandering.

Reducing runoff and pollution from hard surface by installing SuDS can improve water quality and work on a wider scale (7, 8, 19). The costs for river restoration are very variable. A study on restoration projects carried out in the EU has shown that costs can range between 100 to 3000€ (equivalent to about 70-2300£) per metre of river restored (9). The cost of SuDS depends on their type – see other factsheets..

Featured Case Study

Mayesbrook Park The Mayesbrook Park project demonstrates how a green infrastructure approach to urban river restoration is a strong alternative to traditional hard engineering.

By using green infrastructure to address flood-water management, the project has created an attractive public amenity, while the communities that surround the park and the wildlife within it are now able to cope better with the effects of climate change. The overall benefits are substantial relative to the planned investment. The lifetime value of restoring the site across the four ecosystem service categories (provisioning, regulatory, cultural and supporting) yields a grand total of calculated benefits of around £27 million, even if ‘likely significant positive benefits’ for the regulation of air quality and microclimate are excluded. This is compared to the estimated costs of the whole Mayesbrook Park restoration scheme at £3.8 million including the river restoration works. This produces an excellent lifetime benefit-to-cost ratio of £7 of benefits for every £1 invested. http://publications.naturalengland.org.uk/publication/11909565?category=49002

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Social Benefits

Environmental Benefits

Health: Access. * Improved open spaces – in parks and other public open spaces, river restoration can improve their quality, as has been shown for example by the restoration project of the River Quaggy, running through Sutcliffe Park, where about 30% of the visitors only started visiting after the restoration project had improved the area, and 82% reported feeling differently in the park due to better recreational opportunities and higher biodiversity and the surrounding natural environment. Recreational opportunities are improved through increased opportunities for angling, water sports and low intensity activities. Improving pathways to enable active transport can have impacts on physical health.

(1,2,3,4, 5,6,8,11)

Water Quality. * Freshwater systems can dilute and store pollution – however, only to a certain level. River restoration and protection through GI can impact positively on a river’s health: Filter strips and permeable surfaces are specifically important close to rivers to intercept polluted runoff from discharging directly into the river. Preventing polluted runoff from entering the stream by pre-treating it in ponds or wetlands is an important step to reducing this pressure further. (1, 8, 9)

Air Quality. * Air quality is likely to be improved due to denser vegetation and the transport of fresh air along the river corridors – however this could also mean the distribution of pollutants from busy roads. (1,16, 17)

Surface Water. * Draining landscapes into rivers rather than sewers could mean less risk of surface water flooding, however, it might increase flood risk from rivers. River restoration projects have to be carefully planned to accommodate for this function. Creation of floodplain and forest habitats increases runoff infiltration and so reduces the amount of water that needs to be drained away, with suitable natural habitat like medium dense woodlands and meadows likely reducing runoff by appr. 20%. (1, 4, 8, 13,19)

Fluvial Flood. * Restoring rivers, i.e. re-meandering them and establishing vegetation, creating wetlands, slows the flow and increases water storage capacity. It has to be understood where the issue is created (i.e., where does the water come from – upstream or surface water draining into the river?) and the correct measures have to be taken according to this.

Erosion regulation can decrease the need for dredging downstream, reducing flood risk and also labour intensity. (1, 4, 8, 19)

Habitat Provision. * Rivers are amongst the UK’s most diverse and rich ecosystem, and provide ecological connectivity through a landscape. Almost all rivers have been degraded. River restoration has been shown to improve the quality of water and habitat – an improvement of 1-3 classes in the WFD status compared to previous conditions has been found. Morphological status had also improved to moderate in almost half of the case studies, with a third even reaching “good” status (1,8, 9, 18)

Climate Regulation. * Water bodies can have a cooling effect on their local area and so mitigate UHI effect. Wetlands and ponds that might be created through river restoration along with soils and vegetation can store carbon. The effect is size dependent (1, 15). In Seoul, daylighting of a a culverted river and vegetating the surrounding area has led to an average temperature of 14 degrees C lower than surrounding urban area (1, 4, 16)

Low Flows. * Depending on their characteristics, groundwater recharge can occur from rivers. Flow regimes are usually improved after restoration, although this depends on the type of restoration and the drivers of the flow regime.

(1, 4)

55

Cultural Benefits

Aesthetics. * river landscapes are one of the most attractive landscapes, and this aesthetic quality provides many benefits by drawing people to the area. The effect on mental health has been described above and is also reflected in property values. About 60% of the case studies evaluated in the 2004 URBEM report showed improvement of aesthetics after the river restoration project. (1, 2, 3, 4, 5, 6)

Cultural Activities. * Reconnecting people to the natural environment (which in turn increases happiness) can be achieved by restoring natural landscapes in urban settings and making them accessible. This also increases the possibility to use them as educational resources, especially in urban settings where similar rural environments may not be as easily accessible. Water is connected to many activities that are not only recreational and benefit human health but also have cultural traditions connected to them, like angling or bird watching. At Mayesbrook Park (see case studies), the benefits from cultural service provision through restoration of an urban stream can be valued at £820,000 per year (1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13)

Economic Benefits

Property Value. * View of water or a garden adjacent to water can have a significant positive impact on property values, with studies showing increases in value from 10% even more than 30%. (1, 8, 18)

Flood Damage. * Through their contribution to surface water drainage and regulating flows, healthy river ecosystems can help reduce severity of flooding. The Mayes Brook Restoration, for example, shows an annual benefit in improved flood management of £10,000. (4).

Additional Benefits and Potential Costs Improved sales – high quality environments lead to an increase in money spent in local businesses and also encourage businesses to settle in an area.

No additional impacts.

Employment – settlement of businesses in an attractive area can increase the local employment rate. Additionally, through the creation of parks new opportunities for businesses (cafes, outdoor recreation facilities) can improve the employment situation.

Mental health: water bodies have been found to be particularly significant in shaping people’s sense of place and improving their mental wellbeing. They provide attractive, stimulating features that have the ability to restore attentiveness and inspire creativity, and landscapes with water are perceived as more restorative than those without – even to the extent that urban landscapes featuring water are seen to be as restorative as green landscapes.

Additionally, the improved recreational opportunities can give rise to increased social activities. Views of water and the sound of water have been shown to alleviate stress more effectively than other types of natural setting.

Crime and social cohesion– as restoration provides an opportunity for partnership working, the improved community ownership of places where restoration has been undertaken by an engaged community is likely to reduce crime and vandalism in the area (see “Access” and “Public Parks” factsheet) and increase the social connections between people living in the area. *** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

56

References: (1)

(2)

(3)

(4)

Maltby, E., Ormerod, S., Acreman, M., Blackwell, M., Durance, I., Everard, M., Morris, J., Spray, C. (2011) Freshwaters – Open Waters, Wetlands and Floodplains. In: The UK National Ecosystem Assessment Technical Report. UK National Ecosystem Assessment, UNEP-WCMC, Cambridge. van den Berg, M., Wendel-Vos, W., van Poppel, M., Kemper, H., van Mechelen, W. and Maas, J. (2015) ‘Health benefits of green spaces in the living environment: A systematic review of epidemiological studies’, Urban Forestry & Urban Greening, 14(4), pp. 806–816.

Commission for Architecture and the Built Environment (2005) Decent parks? Decent behaviour?: The link between the quality of parks and user behaviour, pp.1–17.

Everard, M. and Moggridge, H. L. (2012) ‘Rediscovering the value of urban rivers’, (April 2011), pp. 293–314.

(5)

Jackson, R. J., Watson, T. D., Tsiu, A., Shulaker, B., Hopp, S. and Popovic, M. (2014) Urban River Parkways. Los Angeles.

(6)

Nordh, H., Hartig, T., Hagerhall, C. M. and Fry, G. (2009) ‘Components of small urban parks that predict the possibility for restoration’, Urban Forestry & Urban Greening, 8(4), pp. 225–235.

(7)

Palmer, M. A., Bernhardt, E. S., Allan, J. D., Lake, P. S., Alexander, G., Brooks, S (2005) ‘Standards for ecologically successful river restoration’, Journal of Applied Ecology, 42(2), pp. 208–217.

(8)

RESTORE (2013) Rivers by Design. Bristol.

(9)

Schanze, J., Olfert, A., Tourbier, J. T., Gersdorf, I. and Schwager, T. (2004) Existing Urban River Rehabilitation Schemes. Wallingford.

(10) Völker, S. & Kistemann, T., (2013) “I’m always entirely happy when I'm here!” Urban blue enhancing human health and well-being in Cologne and Düsseldorf, Germany. Social science & medicine (1982), 78, pp.113–24.

(11) White, M., Smith, A., Humphryes, K., Pahl, S., Snelling, D. and Depledge, M. (2010) ‘Blue space: The importance of water for preference, affect,

and restorativeness ratings of natural and built scenes’, Journal of Environmental Psychology, 30(4), pp. 482–493.

(12) Zelenski, J.M. & Nisbet, E.K. (2012). Happiness and Feeling Connected: The Distinct Role of Nature Relatedness. Environment and Behavior, 46(1), pp.3–23.

(13) Sunderland, T. (2012) Microeconomic Evidence for the Benefits of Investment in the Environment Review, Natural England Research Reports, Number 033.

(14) Environment Agency (2009) Water for life and livelihoods. River Basin and Management Plan Thames River Basin District. Annex G: Pressures and risks.

(15) Kayranli, B., Scholz, M., Mustafa, A. and Hedmark, Å. (2009) ‘Carbon Storage and Fluxes within Freshwater Wetlands: a Critical Review’, Wetlands, 30(1), pp. 111–124.

(16) Hathway, E. A. and Sharples, S. (2012) ‘The interaction of rivers and urban form in mitigating the Urban Heat Island effect: A UK case study’, Building and Environment, 58, pp. 14–22.

(17) Wood, C. R., Pauscher, L., Ward, H. C., Kotthaus, S., Barlow, J., Gouvea, M., Lane, S. E. and Grimmond, C. S. B. (2013) ‘Wind observations above an urban river using a new lidar technique, scintillometry and anemometry’, Science of the Total Environment. Elsevier.

(18) International Association of Certified Home Inspectors, Inc. (InterNACHI) (2016): Constructed Wetlands: The Economic Benefits of Runoff Controls.

(19) http://www.ecrr.org/RiverRestoration/Urban RiverRestoration/tabid/3177/Default.aspx

More links: (20) http://www.urbem.net/index.html (21) https://www.restorerivers.eu/.

57

PRIVATE GARDENS In 2002, an estimated 27 million people in the UK owned gardens. Domestic gardens contribute about a quarter of the total urban area in typical cities in the UK and contribute up to 86% of the total number of trees in a city. Especially small gardens are important, as they contribute the greatest proportion to the total area of gardens and the accumulated number of structures such as ponds, nesting sites or compost heaps is significant at the city scale. This indicates the importance of gardens on a wider scale, not only for humans but also nature. Private gardens are mainly used for relaxation and recreation, with over a third of garden owners surveyed (2011) naming these as main activities; with gardening, eating, drying laundry and socialising being other common activities. Over 80% of gardens are used for more than one of these activities. (4, 14)

Benefits Wheel

Shows the contribution of parks to the provision of ecosystem services.

More detail on the next page.

Landscape context The vegetated, permeable area provided by gardens is reduced each year due to development pressures, individual choices regarding the design of the garden and its maintenance and to provide space for private vehicles.

In London, for example, an area of 2.5 Hyde Parks (2.5x142 ha) of vegetated garden land is lost each year (14), and in a case study area in Leeds, paved area in gardens increased by 13% over the course of 10 years (12). While domestic gardens have significant positive benefits for their owners, they are not accessible to the wider public and do therefore not contribute to increasing public access to green space. Especially domestic back gardens may not even provide aesthetic benefits as they may be hidden behind house fronts or fences/walls. This has implications on the ability of gardens to provide benefits – on a local as well as a citywide scale. Fragmented habitats can also be unable to support wildlife even though the conditions would be given, connecting these habitats (e.g. through tree lined streets for birds) and managing them on a larger scale, e.g. as a group of gardens in an area, could be an interesting opportunity to maximise their habitat potential. Benefits from individual gardens to the wider public could also be maximised by strategically managing gardens on a larger scale than the individual plot.

Maximising benefits: how could we make the most of gardens?

Featured Case Study

Manage gardens on a larger scale: this could allow habitat connectivity and optimise benefit provision for all.

Improve soil structure and include ponds to maximise infiltration and allow storage of water in designated areas. Reduce use of pesticides and fertilizer to prevent polluted runoff and use of mains water for irrigation.

Open up walls to make gardens visible and increase the attractiveness of the area. Inform on the ways gardens can be used for exercise, education and play in different demographics..

Perry, T. and Nawaz, R. (2008) ‘An investigation into the extent and impacts of hard surfacing of domestic gardens in an area of Leeds, United Kingdom’, Landscape and Urban Planning, 86(1), pp. 1–13.

A study in Leeds has linked the increase in paved front gardens (and therefore increase in impermeable area) to an increased severity in surface water flooding in that area. A 13% increase in paved area was observed over 33 years, of which 75% is due to paving of front gardens, that lead to a predicted 12% increase of average surface water runoff.

This prediction was reflected by actual events in Leeds, where heavy rainfall led to more frequent and severe flooding (Perry and Nawaz, 2008). While this study was focussed on front gardens being paved, there is no reason to assume that the loss of back gardens would have a different effect.

58

Social Benefits

Environmental Benefits

Health: Access. * For those able to use them, they can provide increased physical fitness, connection to nature, improved relaxation and recovery from trauma, and similar benefits related to stress avoidance and cognitive function.

Gardening in one’s own garden has been shown to provide greater satisfaction than gardening in community/shared gardens. Where visible, the increased green space may help reduce mental fatigue and so have a positive impact on crime rates in an area. Private Gardens may have an especially important effect on young children due to being more readily accessible for children and providing a safe area for play and exercise. Private Gardens can also be hugely important resources for the elderly, however there can be barriers from decreased physical ability and lack of support. (1, 2, 4, 6, 8, 13)

Water Quality. * Reducing runoff improves water quality as less pollutants are carried into surface water bodies, but also because biological processes in the soil break down pollutants.

Bioretention (the breakdown of pollutants in structures consisting of porous soil, mulch and various plants) has been shown to have significant potential to reduce pollution in runoff. Especially metals can be nearly completely (>90%) removed, ammonium and phosphorous have been found to be reduced by 60-80%. Nitrate, however, can be increased through bioretention treatment. Private gardens, especially if they are managed traditionally, are likely to contribute to nitrogen and pesticide pollution and could so even have a negative impact. (2,3)

Air Quality. * Especially in gardens with trees (at least certain types) air quality can be significantly improved. This is dependent on the type of vegetation used and where it is planted. Trees are especially positive if they are on the leeward side of a high pollution area (e.g. a busy road). They can not only benefit those owning the domestic garden but the area surrounding them – depending on their size and location. However, there is little direct evidence available and effects are certainly only on a small scale. (2)

Surface Water. * Plants and trees intercept rain and slow runoff, contributing to an attenuation of the peak flow and volume reduction of runoff through increased infiltration.

However, heavy and prolonged rainfall, with potential additional runoff from adjacent areas, can lead to waterlogging of the soil. This depends on local characteristics such as soil type and can be exacerbated by compacting the soil, e.g. through heavy footfall or parking of vehicles. (2, 12, 13, 17)

Fluvial Flood. * Urbanisation and decreased permeability of surfaces has been shown to impact the magnitude of flooding by increasing the amount of runoff a river receives. Increasing permeability of an area by 30% could lead to as much as a doubling in the magnitude of 100 year return period floods.

Protecting permeable areas is therefore a significant contribution to keeping flood risk as low as possible. (9)

Habitat Provision. * Especially for invertebrates and birds, even small domestic gardens can provide an important habitat, but also for some animals that used to be common in lowintensity farmland (e.g. hedgehogs, frogs, bumblebees). They are likely to support a fairly generalist array of species, though the importance of this should not be underestimated. Gardens have been shown to harbour more plant species (a study found the entire garden flora across the UK to consist of 1056 species) than any other form of urban green space. Plant composition can be homogenous though and include many non-natives. Another important factor can be the size of gardens: the ability to provide biodiversity is often related to the area and connectivity. While gardens have the potential to provide very valuable habitats, the way they are managed influences the realisation thereof greatly. (2, 5, 7, 10, 11, 13, 15)

Climate Regulation. * A 10% increase in veg surfaces would help control summer temperature increase (predicted 4 degrees) due to climate change (modelling study in Manchester). Additionally, the soil can store carbon, especially if disturbance is minimised. An average of 2.5 kg m-2 of carbon is stored in domestic gardens with 83% in soil (to 600mm depth), 16% in trees and shrubs and only 0.6% on average in grass and herbaceous plants. (2, 13)

Low Flows. * Infiltration allows groundwater recharge.

Grassed areas are able to nearly completely eliminate runoff.

However, increased water use in summer may occur and increase pressure on mains water. (2)

59

Cultural Benefits

Aesthetics. * Gardens, where they are visible, provide high aesthetic benefits for the neighbourhood. In a study in Sheffield published in 2000, more than 50% surveyed stated the fact that gardening created “a more beautiful environment” as a contribution gardens make to the urban environment. (4)

Cultural Activities. * Gardening has been linked to increased sense of self-esteem, identity and ownership. They can lead to strong place attachment and provide a forum for interaction between family members. Gardens allow playful activities as well as growing food, gardening to shape a place after one’s own imagination or creative activities like painting or photography. Private gardens may, however, completely discourage wider social interaction by providing a clear barrier to the outside through hedges and walls – this is dependent on their layout and the way they are used.

Contrarily, it has also been found that private gardens encourage social interaction between neighbours as contacts are made across the garden fence – a study published in 2000 found that 23% of garden users value the opportunity to meet neighbours when in the garden. (1, 6, 8, 16)

Economic Benefits

Property Value. * It is widely accepted that gardens add value to a property. A survey by HomeSearch found that a garden added 20% in value compared to a house without a garden. (19)

Flood Damage. * While a single garden will have no significant impact, case studies like the previously mentioned one in Leeds show that the loss of a proportion of gardens in an area can contribute significantly to increased damage from surface water flooding).

Additional Benefits and Potential Costs Energy savings. Sheltering vegetation could reduce energy costs for heating and cooling – on average 30% cooling energy savings have been found. These can be maximised by choosing vegetation with a high albedo to increase the reflection of light and with it heat. At the same time, this relates to soil water availability, as evaporation and transpiration are the main reasons for the cooling effect.

Winter heating savings can also be gained if gardens are used to plant hedges to insulate from wind (while avoiding shading the house too much or directing wind tunnels towards the house), 17% have been suggested for houses in Scotland, although there is less literature. (2,17)

Carbon Emissions. Management of gardens can lead to an increase in emissions. This can be due either to the products and services used (greenhouses, peat, plastics etc) or the activities carried out (lawn mowing…). This means it is important to be conscious of how to manage a garden for it to be environmentally sustainable. (2)

(Mental) Health. Gardens and gardening provide benefits through the physical exercise that they can facilitate as well as through providing a ‘retreat’ from everyday life and enabling interaction with nature. Reduced mortality, lowered blood pressure and cholesterol levels, increased bone density have been linked to gardening, as well as a later onset of dementia. Regular physical exercise reduces risk of coronary heart disease. The low intensity, regular exercise that gardening provides can be very beneficial. Gardening helps reduce depression and anxiety, and encourages creativity and self-expression. Views of nature encourage faster recovery from illnesses and increase attention, alertness and improved moods. Especially landscapes with high natural resemblance provide restorative benefits. (1,2,4)

Water Quality. Using fertilizers and pesticides can have negative impacts on the water quality of receiving waters. If possible, these should not be used or substituted by organic products to minimise impacts. Keeping a compost heap can provide fertilizer and reduce waste production. (3, 11)

Water Use. The need for irrigation can increase water use in a garden and so demand on mains water and energy. This can have negative impacts on low flows and carbon emissions, or if not done decrease the cooling potential and aesthetic value. Choosing the right plants is important. (2)

Habitat Provision. Introduction of invasive species can be a problem. Also, using pesticides can diminish the value of gardens as a habitat. Native plants should be preferred and management intensities should be kept at a reasonable level – introducing areas for wildlife, like wildflower strips or leaving piles of leaf litter and dead wood can increase the value as a habitat. Domestic cats can also present a threat to wildlife.

(7, 11)

Food. Food production is another potential activity carried out in private gardens. It has been shown that people owning an allotment are more likely to consume fresh fruit and vegetables, and this is likely transferable to private gardens.

However, there is little literature on the extent of food production in private gardens or the implications it has. (16) *** Indication of confidence. * Literature confirms positive influence. * Mostly positive results in literature and/or little literature available. * Varying results in literature, little literature available

60

References: (1)

(2)

Bhatti, M. (2006) ‘“When I”m in the garden I can create my own paradise’: Homes and gardens in later life’, The Sociological Review, 54(2), pp. 318– 341.

(3)

Davis, A. P., Shokouhian, M., Sharma, H. and Minami, C. (2001) ‘Laboratory study of biological retention for urban stormwater management.’, Water environment research: a research publication of the Water Environment Federation, 73(1), pp. 5–14.

(4)

Dunnett, N. and Qasim, M. (2000) ‘Perceived Benefits to Human Well-being of Urban Gardens’, HortTechnology, 10(1), pp.

40–45.

Private gardens occupy a significant proportion of the total surface area of a British city. For many people, the garden represents their only contact with nature and their chance to express themselves creatively. Yet relatively little research has been carried out on the role and value of such gardens to human well-being.

We report in this paper on a major survey on the role of private, urban gardens in human well-being, conducted with a wide cross-section of randomly selected garden owners from the city of Sheffield, England, over the summer of 1995.

(6)

(7)

Cameron, R., Blanusa, T., Taylor, J., Salisbury, A., Halstead, A., Henricot, B. and Thompson, K. (2012) The domestic garden: its contribution to urban green infrastructure. Urban Forestry and Urban Greening, 11 (2). pp. 129-137.

The review suggests that there are significant differences in both form and management of domestic gardens which radically influence the benefits.

Nevertheless, gardens can play a strong role in improving the environmental impact of the domestic curtilage, e.g. by insulating houses against temperature extremes they can reduce domestic energy use.

Gardens also improve localized air cooling, help mitigate flooding and provide a haven for wildlife. Less favourable aspects include contributions of gardens and gardening to greenhouse gas emissions, misuse of fertilizers and pesticides, and introduction of alien plant species. Due to the close proximity to the home and hence accessibility for many, possibly the greatest benefit of the domestic garden is on human health and well-being, but further work is required to define this clearly within the wider context of green infrastructure.

(5)

du vieillissement. Cambridge University Press, 24(04), p. 367.

Gaston, K. J., Warren, P. H., Thompson, K. and Smith, R. M. (2005) ‘Urban Domestic Gardens (IV): The Extent of the Resource and its Associated Features’, Biodiversity and Conservation, 14(14), pp. 3327–3349.

Gigliotti, C. M. and Jarrott, S. E. (2010) ‘Effects of Horticulture Therapy on Engagement and Affect’, Canadian Journal on Aging / La Revue canadienne

Goddard, M. A., Dougill, A. J. and Benton, T. G. (2010) ‘Scaling up from gardens: biodiversity conservation in urban environments.’, Trends in ecology & evolution, 25(2), pp. 90–8.

A scale-dependent tension is apparent in garden management, whereby the individual garden is much smaller than the unit of management needed to retain viable populations. To overcome this, here we suggest mechanisms for encouraging 'wildlife-friendly' management of collections of gardens across scales from the neighbourhood to the city.

(8)

Gross, H. and Lane, N. (2007) ‘Landscapes of the lifespan: Exploring accounts of own gardens and gardening’, Journal of Environmental Psychology, 27(3), pp. 225–241.

(9)

Hollis, G. E. (1975) ‘The effect of urbanization on floods of different recurrence interval’, Water Resources Research, 11(3), pp. 431–435.

Studies have shown that the urbanization of a catchment can drastically change the flood characteristics of a river. Published results are synthesized to show the general relationship between the increase in flood flows following urbanization and both the percentage of the basin paved and the flood recurrence interval. In general, (1) floods with a return period of a year or longer are not affected by a 5% paving of their catchment, (2) small floods may be increased by 10 times by urbanization, (3) floods with a return period of 100 yr may be doubled in size by a 30% paving of the basin, and (4) the effect of urbanization declines, in relative terms, as flood recurrence intervals increase.

(10) Loram, A., Thompson, K., Warren, P. H. and Gaston, K. J. (2008) ‘Urban domestic gardens (XII): The richness and composition of the flora in five UK cities’, Journal of Vegetation Science, 19(3), pp.

321–330.

(11) Loram, A., Warren, P., Thompson, K. and Gaston, K. (2011) ‘Urban domestic gardens: the effects of human interventions on garden composition.’, Environmental management, 48(4), pp. 808–24.

(12) Perry, T. and Nawaz, R. (2008) ‘An investigation into the extent and impacts of hard surfacing of domestic gardens in an area of Leeds, United Kingdom’, Landscape and Urban Planning, 86(1), pp. 1–13.

(13) Royal Horticultural Society (2011) Gardening matters: Urban gardens. London.

(14) Smith,

C. (2010) London: Garden City?

Investigating the changing anatomy of London’s private gardens, and the scale of their loss.,

61 Greenspace Information for Greater London.

London.

(18) Royal Horticultural Society (2016) Waterlogging

(15) Smith, R. M., Warren, P. H., Thompson, K. and

www.rhs.org.uk/Advice/Profile?PID=235 (accessed on 04/05/16)

Gaston, K. J. (2005) ‘Urban domestic gardens (VI): environmental correlates of invertebrate species richness’, Biodiversity and Conservation, 15(8), pp.

2415–2438.

(16) Taylor, J. R. and Lovell, S. T. (2013) ‘Urban home food gardens in the Global North: research traditions and future directions’, Agriculture and Human Values, 31(2), pp. 285–305.

(17) Tompkins, E. L. and Eakin, H. (2012) ‘Managing private and public adaptation to climate change’, Global Environmental Change, 22(1), pp. 3–11.

and Flooding.

Advice on preventing and dealing with water logging

(19) This Is Money (2015): So the 'Waitrose effect' adds 12% to your home's value - but what else will? Ten top factors that boost a property's price... http://www.thisismoney.co.uk/money/mortgagesho me/article-3033530/Ten-factors-boost-property-sprice.html (Accessed on 04/05/2016

62

ACCESS While green spaces have numerous benefits that arise from passive use, like viewing it, from the effect is has on air quality or infiltration or through improving aesthetics – in short, benefits that arise without a human actually having to step into the space – there are a number of benefits that can only be gained by using green space actively. Even for some those benefits that can be gained through passive use – like mental health wellbeing from viewing green space – the space has to be visually accessible. Many of the services green infrastructure provides only turn into benefits when access to the space itself is granted. This is not only a question of putting in doors or pathways, but of making accessing a greenspace safe, attractive and easy and providing the right environment for people to enjoy benefits. This means, access is in a way also a question of design – especially as poor quality green space is often not used and can mean negative impacts rather than positive ones. This does not only apply to parks or general amenity spaces but also green roofs, pocket parks and similar, and these opportunities should not be underestimated in providing access to green spaces in a dense urban environment.

Benefits of accessible green space Mental wellbeing. One in four people in England experience poor mental health at any given time. Green spaces can contribute to improved mental wellbeing either by encouraging physical exercise and play, providing space for “escape” and have been shown to make significant contributions to an individual’s wellbeing in many different ways: Some of the mental health benefits do not necessarily need physical access to a green space but can already be increased by providing a view of them as it is the aesthetic experience that gives rise to the positive effects (1). There is evidence on the impact of quality of the green space at hand (2). Having access to green space has been shown to improve mental health considerably and sustainably (3), and natural views can promote drops in blood pressure, increase focus and reduce feelings of stress, even if only short exposure (40 seconds) happens (4). Children with ADD have been found to benefit from activity in public, especially green spaces (5). Play in vegetated areas has been shown to inspire more imaginative activities and breaks during schooldays improve learning for children. Social development through play with others is also an important benefit of these areas (1).  Connection with nature and sense of place are important factors in an individual’s wellbeing and have been shown to be connected to greenspaces6.  Parks and other green areas provide meeting spaces and venues for social events. This can increase social interaction over a neighbourhood and increase residents’ overall satisfaction with their area (17).

Physical Wellbeing. The ability to exercise and travel actively has impacts on physical wellbeing. Green spaces have been shown to facilitate physical exercise for those living near them, and streets with trees show higher cycle traffic than those without. Examples of benefits are:  Increased likelihood of physical activity and therefore lower obesity rates and lower rates of cardiovascular diseases. People who live furthest away from public green space are 27% more likely to suffer from obesity (1, 8, 9, 10).  Lower overall mortality rates – although differences have been found between different demographic groups, overall a positive relationship between green space provision and health has been found (11).  Lower air temperatures during heatwaves – green spaces (where they are big enough) can provide shelter from hot temperatures during prolonged periods outside in the urban environment (17).

Economic Benefits. Attractive areas lead to higher business investment and more visitor-spending. Additionally, jobs can be created in the maintenance and creation of green spaces (5, 7). While some of the benefits laid out below arise from improved mental and physical wellbeing, it is worth showing the contribution they can make to the economy:  Obesity is an ever increasing strain on the NHS and is linked to physical inactivity (1).  Millions of working days are lost due to stress related employee absence (1, 2).

Featured Case Study

 NHS Scotland has been estimated to save £85 million per year if only 1 in 100 inactive people took adequate exercise (5).

Finlathen Park, Dundee.

This research is part of the Scottish Government’s GreenHealth project. Participatory techniques have been used in a case study to identify community opinions on current uses of urban green and open spaces, and options for the future.

Findings show the importance of the multiple services provided by green spaces, such as places for relaxation and escape, and desires to improve the quality and range of benefits.

More: http://www.hutton.ac.uk/sites/default/files/files/no5%20greenspace %20services.pdf

63

Enabling Access Physical Accessibility

Maintenance

Information

For many people, but especially for groups like elderly or disabled, physical access and the state of the environment can inhibit use of a greenspace. Improve access with:

Visible lack of maintenance can have a negative impact on the use of green space. Be aware of:

Lack of information about existence or facilities available in a greenspace can be a barrier to its use.

 Signs and maps close throughout the park

to

and

 Maintenance of footpaths  Public transport connections

 Litter removal and damage/vandalism

repair

of

 Overgrown vegetation and dog mess (Potential trade-off: overgrown, wild areas may be perceived as untidy but be important factors for wildlife.

Make sure to designate specific wildlife areas and provide explanatory signs.)

 Make information about facilities and services and how they can be used easily accessible (e.g. online)  Within the area, maps and signs help find important services and areas  introduce staff (e.g. rangers, gardeners, volunteers) into the area to provide a first point of contact and community interaction

 Information on how and where damage should be reported and rapid response

Safety

Comfort

Community Ownership

Perceived safety risks are a key barrier to the use of green spaces. Improve access with:

While a greenspace consisting of only vegetation and pathways may provide a nice corridor to walk through, ensuring certain needs can be met locally can increase time spent in a space and its attractiveness to new groups.

Local communities often want to be involved of the management of ‘their’ space. This can work in multiple ways and be coordinated via existing groups (e.g. schools) or ones that are specifically set up for a particular space:

 Especially in bigger areas, having well maintained facilities addressing different target groups like cafes and public toilets can increase use by existing user groups and attract new groups.

 Involving ‘problem groups’ can avoid single group dominance in public spaces and help increase use and make the space safer.

 Sufficient lighting. Street lighting has been shown to reduce levels of crime, and increase levels of perceived safeness.  Avoid dense wooded13 or shrubby areas, and maintain lines of sight and visibility of exits throughout the area, and take advantage of existing infrastructure and buildings for natural surveillance (e.g. visibility form cafes, offices…).  Wide main paths to give pedestrians enough space to pass by.

 Providing specific areas for dogs (increase use by dog owners and make other user groups feel more comfortable)

 Community lead green space management can address local needs differently and possibly allow better maintenance without increased budget  Working with other communities or groups with similar remits and aims opens opportunities for collaboration and knowledge transfer

Maximising benefits: how could we make the most of gardens?

Some benefits can be maximised by taking some things into consideration when restoring/designing green space: Educational Value  Signs explaining natural features and informing target groups (e.g. schools) about accessibility of the area Mental Restorative Value  Natural Components have been found to increase the restorative potential of greenspaces. Provision of certain elements is therefore important (e.g. large, sparsely distributed trees, meadow-like areas with flowers, water features) (14, 15, 16, 17)  Provide sheltered places (but keep visibility/safety aspects in mind)  Play areas for children of different ages. To maximise benefits especially for younger children, a challenging, varied environment is likely to increase development of balance, co-ordination and creativity.  Access to natural ‘wild’ areas provide different social and cultural benefits – e.g. inspiring children to more imaginative play and so increasing their cognitive abilities, Physical Health  Facilities supporting recreational activities – this can also mean use of land like detention basins where they are not vegetated – e.g. as skate boarding areas, basketball courts, etc (depending on size and suitability).  High and low intensity activities should be encouraged – walking paths as well as exercise areas are therefore useful

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References: (1)

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Bhatti, M1. BOP Consulting. Green Spaces : The Benefits for London Green Spaces : The Benefits for London. Topical Interest Paper (2013).

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3. Alcock, I., White, M. P., Wheeler, B. W., Fleming, L. E. & Depledge, M. H. Longitudinal effects on mental health of moving to greener and less green urban areas. Environ. Sci. Technol. 48, 1247–55 (2014).

4. Lee, K. E., Williams, K. J. H., Sargent, L. D., Williams, N. S. G. & Johnson, K. A. 40-second green roof views sustain attention: The role of micro-breaks in attention restoration. J. Environ.

Psychol. 42, 182–189 (2015).

5. Woolley, H., Rose, S., Carmona, M. & Freedman, J. The Value of Public Space. Exchange Organizational Behavior Teaching Journal (2004).

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6. Zelenski, J. M. & Nisbet, E. K. Happiness and Feeling Connected: The Distinct Role of Nature Relatedness. Environ. Behav. 46, 3–23 (2012).

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7. Forest Research. Benefits of Green Infrastructure. (2010).

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8. Coombes, E., Jones, A. P. & Hillsdon, M. The relationship of physical activity and overweight to objectively measured green space accessibility and use. Soc. Sci. Med. 70, 816–22 (2010).

9. Faculty of Public Health. Great Outdoors : How Our Natural Health Service Uses Green Space To Improve Wellbeing. 1–8 (2010).

(10) 10. Mitchell, R. & Popham, F. Greenspace, urbanity and health: relationships in England. J. Epidemiol.

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(11) 11. van den Berg, M. et al. Health benefits of green spaces in the living environment: A systematic review of epidemiological studies. Urban For. Urban Green. 14, 806–816 (2015).

(12) 12. Sunderland, T. Microeconomic Evidence for the Benefits of Investment in the Environment - Review.

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(13) 13. Milligan, C. & Bingley, A. Restorative places or scary spaces? The impact of woodland on the mental well-being of young adults. Health Place 13, 799–811 (2007).

(14) 14. Nordh, H., Hartig, T., Hagerhall, C. M. & Fry, G. Components of small urban parks that predict the possibility for restoration. Urban For. Urban Green. 8, 225–235 (2009).

(15) 15. White, M. et al. Blue space: The importance of water for preference, affect, and restorativeness ratings of natural and built scenes. J. Environ.

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(16) 16. Völker, S. & Kistemann, T. ‘I’m always entirely happy when I'm here!’ Urban blue enhancing human health and well-being in Cologne and Düsseldorf, Germany. Soc. Sci. Med. 78, 113–24 (2013).

(17) 17. Foley, R. & Kistemann, T. Blue space geographies: Enabling health in place. Health Place 35, 157–65 (2015).

References and Guidance on Giving Access (18) Commission for Architecture and the Built Environment. Decent parks? Decent behaviour?: The link between the quality of parks and user behaviour Contents Foreword. 1–17 (2005).

(19) Crime and Public Safety. How Trees and Vegetation Relate to Aggression and Violence (no date). Available at: https://depts.washington.edu/hhwb/datasheets/GC GH_datasheet.Crime.pdf

(20) Kuo, F. E. and Sullivan, W. C. (2001) ‘Environment and Crime in the Inner City: Does Vegetation Reduce Crime?’, Environment and Behavior, 33(3), pp. 343–367.

(21) McCormack, G. R., Rock, M., Toohey, A. M. and Hignell, D. (2010) ‘Characteristics of urban parks associated with park use and physical activity: a review of qualitative research.’, Health & place, 16(4), pp. 712–26.

(22) National Audit Office (2006) ‘Enhancing Urban Green Space.’, Report by the Comptroller and Auditor General (London).

Weblinks:

(23) Forestry Commission – Accessibility of Green Space http://www.forestry.gov.uk/fr/urgc-7eeggr

(24) Enhancing Urban Greenspace: https://www.nao.org.uk/wpcontent/uploads/2006/03/0506935.pdf

(25) National Recreation and Parks Association, US. Pocket Parks: https://www.nrpa.org/uploadedFiles/nrpaorg/Grant s_and_Partners/Recreation_and_Health/Resource s/Issue_Briefs/Pocket-Parks.pdf

(26) PlacemakingResource – Maximising the use and benefits of public parks and spaces: http://www.placemakingresource.com/article/1364 326/advice-maximising-use-benefits-public-parksspaces/