River Rea Regeneration Project

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Manor (moat) House

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DIGBETH/ HIGHGATE AND DERITEND The site is relatively flat with high areas to the east and west, defined by a fault line that runs northeast - southwest. Sandstone is located on the higher town centre, with mudstone and superficial deposits in the flat valley of the River Rea sloping towards the north to meet the River Tame.

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plants and phytoplankton

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The site’s earliest use was a medieval deer park Holme Park, with the industry centred along Digbeth Road which ran between the crossing of the Rea to Birmingham town centre. A small band of enclosed fields surrounded the deer park, and beyond was open common land. Fast forward two centuries, all the land was enclosed Wide-set streets used extensiveHigh density, low rise industry Historical pubs with fields. At the start of the industrial revolution, a large residential area ly as commuter parking and commercial holdings character was developing along the road of Digbeth and Deritend and allotments The city fabric is consistent in its density with fluctutions in low rise and high rise buildwere a common feature to the peripheral edges. By 1800, the river was ings towards the city centre and to the east. The site area is typically high density, low diverted for industrial and irrigation purposes, however cross-referencing historical rise buildings of brick and steel warehouses with an absence of green space and an maps, these appear to not have stood the test of time for long. Residential housabundance of naturalised planting in forgotten areas such as the river corridor that risk ing mixed with commerical and industrial holdings in the site area until the 1970s, damaging flood defences. Large area of derelict brownfield sites are also a common when the area was repurposed for industry by the city. feature.

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Recognising fish as an indicator species of biodiversity in the River Rea by strategic design intervention to the river channel.

URBAN PALETTE

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Species: brown trout and their associated food chain.

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• The primary aim is to improve the river’s physical and hydrological structure to sustain a fish population.

• The secondary aim is to support this with the design of a high quality spatial landscape that increases biodiversity, while increasing the city’s capacity for rainfall and flood events for the future.

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In order to create an ecosystem for these fish, an understanding of what their needs are at the outset to be established.

• Trout need a gravel river bottom to lay their eggs

o Heavy sediment loads in spawning gravels will kill deposited trout eggs • Trout enjoy a varied diet of land and water insects, smaller trout and other small fish

o A robust green network to encourage land and water wildlife • A variety in depth and variety of structure of edges and base

o change the speed and character of the water.

o ‘Wiggle’ room is important in river biology.

o This creates refuge areas where fish can survive during flood/ drought events

o Trout are dependent on an abundance of clear, cold water.

• Barriers such as weirs, culverts and hatches can prevent resident brown trout from accessing spawning areas and habitat vital to all stages of their life cycle (Wild life trust, n.d.)

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terrestrial insects

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small nymphs

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Hippodrome The Parsonage Theatre (Rectory)

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THEORETICAL POSITION

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Education

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Worcester & Paradise (Old) Wharves

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brown trout

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Bingley Hall

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“It’s great news that brown trout have returned – it’s a clear indicator of the brook’s renewed health as high quality water and a good habitat are vital requirements for them to spawn.

Where they thrive, other wildlife will too.” (Councillor Ann Beech, 2017 on subject of return of brown trout to Lyme Brook)

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fingerling trout

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FISH NEEDS

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The brief aims to accomplish nothing less than a complete transformation in the way the River Rea interacts with its surrounding setting in Digbeth, Deritend and Highgate, the south-west industrial urban area of Birmingham.

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HEALTHY FISH HEALTHY RIVER

River’s background The River Rea’s source is located in Wasely Hills Country Park, a local nature reserve, in Rubery, Birmingham. It winds through residential estates in culverts and channels eastwards to Longbridge (an ongoing development where the river is in the process of being daylighted, see CASE STUDY ONE for more information on one area already complete).

The river then turns north-east along the railtrack and improves in quality at Northfield and Cotteridge where it is allowed to naturally meander in the local nature reserve Kings Norton Park. It is then dammed at Lifford Reservoir built

by Worcester and Birmingham Canal Company in 1815 to compensate Lifford Mill for water lost to the canal. Fishing can be done at Lifford Reservoir, and in flood events fish are sometimes forced into the river (Birmingham City Council, n.d). A local was reflecting on the one time he found a fish at Longbridge it was shortly after a flood, there is the reservoir located upstream. It continues north through built-up suburban towns in a narrow green spine constrained by small channels where there are instances of robust flood defences to protect housing. When it reaches Calthorpe Park, the river is channelled in an open culvert for the remainder of its course through Highgate, Digbeth, Saltley to Graveley Hill interchange where it flows into the River Tame.

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Daylighting: the act of uncovering buried rivers, has the benefit of being top down or bottom up in terms of implementation with success cases for each type.

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Creating a resilient future-proof green and blue infrastructure framework that manages flooding problems and reintroduces pre-existing wildlife corridors

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Hippodrome Theatre

Birmingham Wholesale Markets

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Custard Factory

Digbeth Coach Station

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St Albans Academy

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Vacant Carpark

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Landscape design measures to sustain fish populations in an urban context.

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For references see workbook

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Principle 2 “Healthy places optimise opportunities for working, learning and development.”

It’s an industrial area with a number of educational facilities that lack a relationship with nearby healthy green open space and water environment.

“Contact with nature can enhance personal development in both children and adults.”

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“Healthy places improve air, water and soil quality”

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Highgate Park

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Principle 1 “Aiming to protect the valuable natural resources that are the foundation of our health and wellbeing: air, water and soil.”

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SUSTAINABLE URBAN DRAINAGE SYSTEMS AND WATER COURSES

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PUBLIC HEALTH AND LANDSCAPE

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Geology

20 Bedrock m Mudstone

Superficial deposits Sand and gravel

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Buried channel or valley margin

Excessive carriageway widths SURFACE FLOODING

FLOW AND FORM

STREETSCAPE

Slow down water movement to the river and increase capacity.

High traffic speeds haven’t been an issue in the industrial area of Digbeth, Deritend and Highgate considering the excessive road widths, due to the amount of parking that is present on both sides of the road.

Extensive impermeable surfaces in the Digbeth and Deritend area has consequently meant that surface water rushes towards the typical urban drainage infrastructure after any given precipitation, creating high peaks of water velocity within the river which puts strain on the drainage infrastructure. This renders living conditions within the river almost inhospitable and increasing the likelihood of flash floods.

Flooding in Birmingham has generally been a combination of river flooding, sewer flooding, reservoir flooding and surface water flooding (Atkins, 2014, The Environment Agency, 2017b)

Altering the structure of these hard surfaces to incorporate swales, planting and other green infrastructure will create a hydrological network that increases the capacity of water storage and slow rainfall’s path back to the River Rea.

Over the past century an increase in rainfall has been observed (Climate Research Unit, 2008). Victorian flood defences had been the city’s answer to the management of alluvial water flows to the detriment of river ecology due to the disconnection of green and blue infrastructure. These systems rarely have the capacity to support these changes in rainfall.

In order to accommodate these fluctuations in rainfall, a more resilient hydrology needs to be implemented in the urban environment to support the wildlife that depends on it. Measures have to be taken to slow down water flows by the implementation of SUDS.

WATERSCAPE RESERVOIR FLOODING

PORTER BROOK POCKET PARK A small-scale intervention to the river and an adjacent carpark as part of wider works to the Porter Brook in Sheffield.

Wetlands have been described as ‘the kidneys of the landscape’ because of their valuable role in the regulation of water quality and flow.

Wetlands can break down or lock up contaminants, both in surface water and discharging groundwater, thus improving water quality. (Huber, 2014) RIVER FLOODING

PUBLIC OPEN SPACE In addition to the benefits of deconstructing the river corridor, the visual disconnection from the street and places of employment will cease to exist.

In the smaller deconstructed areas, these will form small green courtyards that strengthen the wildlife corridor and establish blue links from the streetscape to the River Rea. Small public spaces nested within the existing fabric will enhance the working environment which follows along the aims of the Landscape Institute’s Principle 1 and 4.

Case study – Longbridge Town Centre A large scale commercial development with ecology and sustainability as one of their primary drivers, chosen for its’ daylighting the stretch of river present on the site.

Upstream towards the south-east of the Proposed Scheme, is the Longbridge Shopping Centre Development which includes a short section of river that has been rehabilitated. Lowering the levels of topography below street level, an undulating river bank has created a sweeping river course through the development, which acts as an inviting entrance from a busy highway, defined as Austin Park.

The scheme uncovers a section of the River Rea that had been culverted since 1916 (St Modwen, 2009). Diverse riparian vegetation and birch trees line the banks, with narrow winding paths which bring people to the heart of the park from the carpark and shopping centre.

The car park was flagged by the council as an important element in the regeneration of the wider area (SCC, 2014).

The degrading flood defences were an increasingly alarming problem so the idea to create a pocket park was put forward.

The area was a slipway for surface water, consequently a sloping topography towards the river was desirable.

The design opened up the river to the public and created a visual connection with the street, inviting interaction. The stepped terraces are specially designed, so the lower areas accommodate 1 in 100+ flooding events and are constructed from robust gabion walls and concrete.

Planting to improve the appearance of the street was introduced with increased habitat potential. New riparian vegetation and in-channel deflectors caused the flow of the river to wiggle, thus creating a differing range of habitats for fish and other aquatic species.

Trout are now present in the river.

These inspired details are drawn into the River Rea design, and this is a leading example of river rehabilitation for the support of fish ecosystems in urban rivers.

As with all roads within the Digbeth, Highgate and Deritend area, all roads and pavements are a total of 16m wide from wall to wall.

A network crossreferenced with the flood maps has resulted in the creation of a heirarchy of streets with increasing priority of green space that balances the less trafficked routes without compromising the navigation of large vehicles that need to access the industries in the area.

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This area is industrial with wide streets that currently accommodate an extremely large amount of commuter traffic.

The design solutions focus on maintaining usability without removing all the parking capacity while maximising green and blue links.

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MAIN SPINE -2 vehicular lanes -2 cycle lanes -Permeable surfaces -Standard 2m footpaths -Single swale -Single row of trees

MASTERPLAN STRATEGY ROAD main spine

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As the primary spine and main thoroughfare to of the area, the street type is kept free of obstructions and parking. With no current existing green space to these streets, a single central tree line and water filtration swale is introduced to the centre of the street.

Cycle lanes are permeable with blue links to the bioswale that will in turn have blue links to the water filtration ponds in the deconstructed area of the River Rea corridor.

ROAD secondary road ROAD HEIRARCHY OF USE AND GREEN SPACE

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SECONDARY ROUTES: -2 vehicular/cyclist lanes -Permeable surfaces -Standard 2m footpaths -Double swale -Alternating double row of trees -Grate pedestrian crossings -Permeable parking areas

ROAD one way road RIVER existing RIVER in-channel intervention RIVER partial channel break-out RIVER complete channel break-out

The current water corridor has no relationship to the street, with high retaining walls and opaque crossing points so its presence is generally unknown to passers-by.

The development of the heirarchy of interventions have been based on maximising the capacity for green and blue links from the surrounding streetscape back to the River Rea. As seen opposite. Large brownfield sites and poor quality building infrastructure provides the opportunity to extent the footprint of the river channel to improve the in-channel conditions and connection to green infrastructure.

TYPE 1: -Fluctuating water depth -High water velocity -No refuge areas -No vegetation -No ecosystem

RIVER HEIRARCHY OF INTERVENTION

The current status of the river is that there is little life-sustaining features or functions within the 10.2m wide river corridor besides a drainage ditch and a transporter of water from the River Rea to the River Tame. A straight constant channel with a gentle U-shaped profile constructed from brick and concrete. No life is spotted within the river other than rats and ducks. The channel walls are a common canvas for local graffitti artists.

TYPE 1: +Increased water depth +Reduced water velocity +Increased roughness +Gentle meandering introduced - For migration only, not refuge

The in-channel intervention is for areas where the river corridor footprint cannot be increased and there is little scope for green/ blue links to the river, such as the purple areas highlighted on page 20. Working within the constraints, the design allows for a greater, more stable water depth and flow, supported by the SUDS interventions of the site area. An increased roughness and areas of planting provide a small amount of terrestrial and aquatic habitat for insects and other small invertebrates to support fish.

TYPE 2: +Increased water depth +Reduced water velocity +Increased roughness +Gentle meandering introduced +1-sided channel break-down +Green/blue links introduced +Refuge areas introduced +Visual connection introduced

In addition to the benefits of Type 1, Type 2 also includes limited refuge areas, and green/blue links and a visual connection to the streetscape and green spaces set out in the Masterplan Diagram on Page 26. An increased overall area of green space within the channel is balanced by the increased width from the breaking down of one side of the river channel. The increased footprint allows the river to meander more, with deeper side pools for refuge and spawning habitat. The coils to the water are planted with emergent plants such as Common Club-Rush, Flag Iris, Water Mint and Marsh Marigold for faster flowing watercourses

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the secondary routes of the area, the street type is a ance of parking, pedestrians and traffic. With no current sting green space to these streets, an alternating tree enue and water filtration swale is introduced to both sides the street. Cyclists use vehicular routes as these are less fficked areas. e parking spaces are reinforced planted areas that are rmeable with blue links to the adjoining bioswale that will turn have blue links to the water filtration ponds in the constructed area of the River Rea corridor.

TYPE 3: +Increased water depth +Reduced water velocity +Increased roughness +Natural meandering encouraged +Complete removal of channel +Deep pools and water filtration wetland +Increased visual and green/blue connection

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ONE-WAY STREETS: -Single vehicular/ cyclist lane -Permeable surfaces -Wider 2.5m footpaths -Double swale -Double row of trees -Increased permeable parking areas

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As the least trafficked routes, these corridors are centred on green space and pedestrian links. The single vehicular lane maintains usability for articulated lorries.

The green space has alternating functions of bioswales and parking. The wide-set pavements balance these simplified dimensions and increase intervisibility down the street corridor.

In addition to the benefits of Type 1 and 2, the most extensive intervention involves complete removal of the impermeable river corridor and a wider footprint to both sides of the water front. Robust green/ blue links will connect the wider green infrastructure of the streetscape and network of proposed and existing green spaces. SUDS drainage pipes all lead to this area for further water filtration through reed beds back to the River Rea, further stabilising the water cycle and improving the quality of the drainage output. Larger refuge areas and deep pool will house spawning grounds for trout and other wildlife. A wildlife haven that also acts as a public space for local employment that will enrich their working environment.