Rainwater harvesting in Bangladesh

Rainwater harvesting in Bangladesh Potentials, challenges and stakeholders’ responses

Edited by

Dr Md Ashiq Ur Rahman ASM Shafiqur Rahman

Rainwater harvesting in Bangladesh

Rainwater harvesting in Bangladesh Potentials, challenges and stakeholders’ responses

Edited by Dr Md Ashiq Ur Rahman ASM Shafiqur Rahman

ISBN: 978-984-90017-6-8 Published in: June 2013 Published by WaterAid Bangladesh House 97/B, Road 25, Block A Banani, Dhaka 1213, Bangladesh

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Potentials, challenges and stakeholders’ responses

Foreword This book is an outcome of WaterAid Bangladesh’s (WAB) last couple of years endeavour to promote rainwater harvesting. Let me take this opportunity to give a brief background of our journey to promote rainwater harvesting in urban Bangladesh.

The concern of water crisis in urban areas has made WAB interested to understand the situation and solutions through a study which found rainwater harvesting as a probable solution. Realising the potential of rainwater harvesting WAB has consciously taken on a journey to promote it throughout its programmes, with sector actors and at policy level.

Continuing on the path to promote urban rainwater harvesting, we faced multiple challenges of lack of awareness and technical knowhow in terms of practical applications among mass population, academicians, researchers, practitioners and policy makers. We observed that very little knowledge and experience exists for establishing rainwater harvesting in an urban setting. Professionals were unaware of technical and financial modalities of rainwater harvesting including groundwater recharge. We also found that policy support for incorporating rainwater harvesting in structures were inadequate or nonexistent.

With support from Centre for Science and Environment (CSE), India we started rolling-out training programme for practitioners, academicians, researchers, implementers, and policy makers. We were very happy to see that the trainees coming together to form a voluntary platform ‘RAiN Forum’ to promote rainwater harvesting. We constructed a number of demonstration plants for rainwater harvesting at strategic locations and people are now using those as practical examples for learning and research. We also realised that we need to make the engineers, architects and planners aware of the potentials of rainwater harvesting thus organised interactive sessions with their professional bodies. As the sphere of awareness grew, interest among the general public also

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Rainwater harvesting in Bangladesh grew. We started to observe ‘Rain Day’ on the first day of monsoon; First Ashar of Bangla calendar. This event remains open to all offering an opportunity to know about rainwater harvesting. Subsequently we are organising bi-annual national convention on rainwater harvesting.

We are pursuing the educational institutions to incorporate rainwater harvesting in the curricula with modest success.

We are also establishing rain centres in various universities. RAiN Forum’s website (www.rainforum.org) is also a resource that people can access to learn of rainwater harvesting. We are endeavouring to influence policies related to housing construction for incorporating rainwater harvesting as an essential part. We believe rainwater harvesting can be made popular through a concentrated effort of all stakeholders.

This book is a compilation of experiences of people who were introduced to rainwater harvesting through the WAB/CSE trainings for the first time. Some of these articles are academic and some are written as cases giving you an insight into the thinking process of academia and grassroots practitioners. Hope you would enjoy reading.

Md Khairul Islam Country Representative

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Potentials, challenges and stakeholders’ responses

Preface Understanding and acknowledging the water crisis in Bangladesh is now the major challenge for policy makers. This has set a challenge for practitioners and researchers of how to identify alternative water supply sources in a form relevant to decision-making. One of the available sources for addressing the challenge is rainwater harvesting. Rainwater harvesting (RWH) is the accumulation and deposition of rainwater for reuse before it reaches the aquifer. There are numerous positive benefits for harvesting rainwater. The technology is low cost; decentralised system may empower individuals and communities to manage their water. Globally it has been used to improve access to water and sanitation at the local level. In agriculture rainwater harvesting has demonstrated the potential of doubling food production.

Wetland ecosystem along with subsistence function also depends on it.

The biggest challenge with using rainwater harvesting is that it is not included in water policies in many countries. In many cases water management is based on renewable water or reuse, which is surface and groundwater with little consideration of rainwater. Rainwater is taken as a ‘free for all’ resource and the last few years have seen an increase in its use. However, lack of technical knowledge and lack of policy support hinders the potential of rainwater harvesting in Bangladesh. Within this broad challenge of institutional contexts and technical understanding, this book demonstrates innovative ways in which rainwater harvesting system (RWHS) is being perceived by practitioners and academics. The scope of such demonstration is being extended through the initiatives of WaterAid Bangladesh who consider promotion of rainwater harvesting as one of their priority advocacy agenda.

The potential of rainwater harvesting is being demonstrated through the design of RWHS and new substantive tools that provide evidence of how rainwater harvesting system works in different contexts to inform decisions on what policy actions to take. The book, therefore, builds on the stakeholders’ responses, which explored the successful

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Rainwater harvesting in Bangladesh demonstration of RWHS in their premises, showing the potentials of rainwater for involving stakeholder groups. The contributions in this book address some of the gaps in our theoretical and methodological perspectives, as well as issues related to linking practice to policy. The methodological and empirical examples are drawn from case studies of different stakeholders who demonstrated RWHS in collaboration with WaterAid Bangladesh. The book is divided into two parts, which have a logical progression from techniques to practices. Part one is entitled Rainwater harvesting in Bangladesh: Potentials and challenges. The papers in this section reflect on the theoretical and methodological assumptions of RWHS and its potential to address water crisis. The authors, however, in this section attempt to elaborate how the rainwater harvesting system can address water crisis in micro and macro (policy) level. The authors also acknowledge the potential of RWHS in knowledge production. The focuses on potential of RWHS, technical aspects of RWHS and policy measures of RWHS have been highlighted.

This book is, therefore, situated in the new practice context of attempting to integrate rainwater harvesting in academia and public sector actions with greater environmental sustainability and economic efficiency.

Part two focuses on Rainwater harvesting in Bangladesh: Stakeholders' responses. All of the papers in this section provide the brief description of different stakeholders’ responses who collaboratively worked with WaterAid Bangladesh to demonstrate potentials of RWHS. The authors acknowledge that the context can be different but the potential of rainwater harvesting is always a positive phenomenon. These papers portray the responses of different type of stakeholders which include academic institutions and NGOs. The potentials have been identified in the broader themes including knowledge production, academic enhancement, research collaboration, and addressing water crisis. These papers provide a clear understanding on some technical aspects of RWHS to be demonstrated in large scale infrastructures. In this section particular issues that are addressed include components of RWHS, costing of RWHS, and role of collaborative actions to promote RWHS. The papers suggest how these issues can be addressed to provide usable tools, such as criteria and indicators, for practice. Moreover, this book is the initiative to create room for manoeuvre to develop the future course of actions to promote rainwater harvesting system in Bangladesh to combat water crisis.

Dr Md Ashiq Ur Rahman ASM Shafiqur Rahman

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Potentials, challenges and stakeholders’ responses

Contents Foreword

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Preface

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Contents

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PART ONE: Potentials and challenges Rainwater harvesting potentials in educational institution Md Tarikul ISLAM, Md Yasir ARIF & Sheikh Md NOMAAN

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Promoting water conservation and recycling techniques through architectural education: students’ acceptance and perception Md Nawrose FATEMI

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Rainwater harvesting as an alternative source of water supply for Dhaka city: myth or reality?

Anika TABASSUM

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Artificial groundwater recharge through rainwater harvesting in urban residential areas: a study on Niketan area of Dhaka city SA NAHIAN, Kazi Rashed HYDER & Shahnoor HASAN

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Promoting urban rainwater harvesting: policy support, gap and initiatives Syed Azizul HAQ

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Promoting urban rainwater harvesting through educational institutes: a case study of Independent University, Bangladesh Shahnoor HASAN, Kazi Rashed HYDER & Hasin JAHAN

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Rainwater harvesting in Bangladesh

PART TWO: Stakeholders’ responses

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Role of WaterAid for promoting rainwater harvesting in Bangladesh Hasin JAHAN

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Engagement of ITN-BUET to promote rainwater harvesting Maharam DAKUA

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Rainwater harvesting system and aquifer recharge project at MIST Abdullah FARUK & Mohammad ARIFUZZAMAN

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Promoting rainwater in coastal areas of Bangladesh: a case study of sustainable environmental health initiatives project of Nabolok Md Maynuddin SAKE

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Rainwater harvesting demonstration plants in Dhaka Hasin JAHAN & Kazi Rashed HYDER

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BRAC university initiatives on RWH AKM SIRAJUDDIN

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Promoting rainwater harvesting in industry and urban area: initiatives of RAiN forum Md Ashraful ALUM

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Potentials, challenges and stakeholders’ responses

Part ONE Potentials and challenges

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Rainwater harvesting in Bangladesh

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Potentials, challenges and stakeholders’ responses

Rainwater harvesting potentials in educational institution Md Tarikul ISLAM, Md Yasir ARIF & Sheikh Md NOMAAN

Introduction Due to the increasing scarcity of good quality water of sufficient quantity and water related problems like water logging during rainy season, arsenic contamination & ground water deplet io n, water issue remains a major policy concern in urban areas of Bangladesh. It is therefore necessary to make decisions about conservation and allocation of water that are compatible with socio-economic objectives such as economic efficiency, sustainability and equity.

Rainwater Harvesting potential in urban Bangladesh fulfils all the criteria to be economically efficient, sustainable and equitable source of safe water. But due to lack of knowledge and proper design guidelines and awareness the RWH system has not been popularised as it should have been.

Rainwater harvesting is not a new concept in Bangladesh. Limited technical knowledge and lack of demonstration activities limits the potential of RWH in Bangladesh. In this context limited institutional responses have been observed in Bangladesh. Some government agencies like Public Works Department, Department of Architecture,

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Rainwater harvesting in Bangladesh Dhaka Water and Sewerage Authority, Public Health Engineering Department and Local Government Engineering Department has started implementing programmes of rainwater harvesting in a very limited way. Private sectors are also implementing programmes throughout the country to promote urban rainwater harvesting system as the mitigation of water crisis to some extent. In this context, this paper is written with the intention of promoting RWHS by narrating its potentials in an academic institution and developing a completed design for RWHS.

Water scenarios in Bangladesh: present condition in urban areas of Bangladesh Dhaka Water supply and Sewerage Authority (WASA) provides only 75 percent of its city population water demand from extraction of underground water by about 350 deep tube wells. Rests depend upon shallow tube wells or surface water. The total water demand for the population of Dhaka city is about 1500 million litres per day. But the available water supply is 1336 million litres per day. In Chittagong 50 percent of the urban area has been covered by piped water supply system. About 69 percent of urban slums and fringe areas use water from private tube wells and over 29 percent use water from public tube wells. In Khulna only 20 percent of urban area has been covered by public water supply system and in Rajshahi only 19 percent of city dwellers collect water from hand tube wells. In rest 60 districts of Bangladesh, piped water supply system covers only 19 percent of the population in the core areas of those districts, another 27 percent depend upon public hand tube wells. The remaining population depends on private wells, ponds and rivers as their sources of water.

Contour of average annual rainfall over Bangladesh has been developed using GIS for recent 12 years (1996 to 2007) which show relatively higher rainfall in the Eastern part of the country than the Western part.

The spatial distribution of this analysis has also shown in the above figure for 34 BMD stations over Bangladesh. The lowest average annual rainfall is observed in Rajshahi (1532 mm) and highest average annual rainfall is observed in Teknaf (4345 mm) for 12 year average. The figure indicates increase of rainfall in NW region (up to 13%), in NC region (up to 7%), in NE region (up to 9%), in SW region (up to 14%), in SC region (up to 10%), in SE region (up to 4%), in EH region (up to 11%) and in the RE regions (up to 21%). It was observed that average annual rainfall is 2505 mm (5.7% increase considering with last 30 years rainfall).

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Potentials, challenges and stakeholders’ responses

Figure 1: Average annual rainfall (mm) over Bangladesh form 1996-2007

Alternative sources of water It has become clear that most of the rural people can neither be depending upon shallow ground water nor they have access to deep tube well. Most of the urban people are in shortage of water.

Furthermore heavy extraction of ground water causing the water level down by about one meter every year .From the above facts it is understood that from now on we should not be fully dependent upon ground water as the only source of water. We must look for its alternative sources. Among the alternatives, there are only three other options. These are: i) treated wastewater / recycled wastewater ii) treated surface water iii) rainwater.

Cost of water from various sources Cost of water supply includes cost for collection, treatment if needed and its distribution. Among the alternative sources of water, the cost for treatment is be the highest for wastewater and cheapest for rainwater because it is proportionate to the pollution potential present in water.

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Rainwater harvesting in Bangladesh The other factor is the location of sources of water, which incurs cost for collection from the sources and distribution to the consumers. In this regard rainwater is at the doorsteps. So it needs less cost for collection and treatment also. The price of water charged by Dhaka Water Supply and Sewerage Authority (DWASA) for its supplied water is U.S. $ 0.09 per thousand litres. The low income households, who cannot afford a house connection, depends on substandard quality of water from private vendors at a high price, sometimes hundred times higher than that could be provided by public authority. In a study it is revealed that where cost for Dhaka WASA supplied water stands for about BDT 0.2 to 0.25 per litre, the cost for rainwater required only BDT 0.07 per litre.

Methods for calculating the potentials of RWHS For the calculation of rainwater harvesting potential rainfall intensity and run-off coefficient of roof material has been used in this paper. For the calculation of rainfall intensity for Dhaka city data for past 30 years from 16 station points have been collected and the average rainfall intensity has been used for calculation of rainwater harvesting potential.

The measurements for the catchment area have been taken directly from the catchment. The designs for sedimentation and filtration chambers have been done according to the requirement as well as space available for their instalment.

Potential of RWHS in UITS Considering 22 working days and demand varies with using purpose, demand is calculated as following: Table 1: Total demand for the selected purposes Purpose Toilet Flushing Ablution for Prayer Mopping Gardening Total demand

demand ( litres per month) 6,600 8,800 2,200 1,000 18,600

From the calculation total demand for the mentioned purpose is 18,600 litres/month but for the simplicity of the further calculation the demand is assumed 2000 litres/month. For the calculation of RWH potential, average rainfall intensity is taken from the following figure. It is found that the average rainfall intensity over the years is 2150 mm.

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Potentials, challenges and stakeholders’ responses Figure 2: Decadal average rainfall considering 55 year duration (19532007) for Dhaka city 2500 2000 Precipitation ( )

1500 1000 500

0 50s

60s

70s

80s

Recurrence interval (in decades)

90s

2000 to 07

Using the decadal average rainfall intensity 2150 mm and run-off coefficient 0.8 for corrugated tin, the rainfall harvesting potential in UITS is summarised in table 2.

Table 2: Rainwater harvesting potential Catchment Area(m2) Annual average rainfall (m) Machine 136.2 Class Room 263 2.15 Total

RWH potential(L) 2,34,200 4,52,500 686700

Figure 3: Design of RWHS

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Rainwater harvesting in Bangladesh

Results and discussion The system is designed with two first flush devices having the length of 19 m and 36 m for the catchment of machine shop and classroom accordingly. To design the storage tank over the year water deficiency is calculated and shown in figure 4.

Figure 4: RWH potential and demand

Deficiency during the month of November-December-January-February is 56679.712 L. Rest of Eight months can easily be served by the rainwater. Cost-effective size of the storage tank is 9.5 ft*6.5ft*6ft. (considering during the month from March to October heavy shower will fulfil the Tank Twice). A siltation chamber of size 6ft*3ft*5ft with capacity 2500L will accommodate 25 percent of potential volume of rainfall during high intensity before passing the sedimentation chamber.

The sedimentation chamber will consist of 3 or 4 layers of material varying from coarse chips to fine sand.

As the infiltration rate of fine particles is quite low (0.15 to 0.25 L/sec for 1m2 filter chamber), a sedimentation unit of size 6ft*3ft*5ft will yield 1505 litre filtrated water per hour. As first 42 m soil is clay and silt, recharge should be performed at a depth from 42 m to 109.73 because this soil strata contains fine sand (FM=1.6). To recharge rainwater in the first aquifer, 60 ft strainer with slot number 30 will be adequate.

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Potentials, challenges and stakeholders’ responses A recharge unit of size 6ft x 4ft x 6ft with recharge capacity 4200l/hr will take about 2.25 hr to empty the recharge tank. From the pay back analysis it is found that about 30,000 BDT will be saved every year and the payback period for this project is about 10 years.

Concluding remarks Rainwater harvesting is a part of integrated water management to mitigate the water crisis not only for the Bangladesh but also for the whole world. Water in the world is treated as an economic product and rainwater harvesting system is an efficient way to achieve a sustainable source of this most necessary product. But for the sustainability of the system some research regarding the quality of water, contribution to the water footprint from the consumers and detailed economic and environmental evaluation should have to be done. Also as the system installed in the UITS campus includes recharging the aquifer for which sufficient testing of the chemical property of the water should have to be conducted.

References Ahmed M F (1999) Rainwater harvesting potential in Bangladesh, Proceedings of the 25t h WEDC Conference: Integrated Development for Water Supply and Sanitation, Addis Ababa, pp 363 –365 Asati S R and Deshpande A (2006) Importance of Rainwater Harvesting in Current Scenario, National Seminar on Rainwater Harvesting and Water Management, Nagpur

BBS (2001) Population Census: National Report, Bangladesh Bureau of Statistics BMD (2010) Climate of Bangladesh, Bangladesh Meteorological Department Coombes P J, Spinks A, Evans C and Dunstan H (2004) Performance of rainwater tanks in Carrington: NSW during a drought, WSUD, Australia

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Rainwater harvesting in Bangladesh Dhaka Water Supply and Sewerage Authority (2008) Annual Report 2007-08, Dhaka Islam M M (2001) Study on Rainwater Harvesting Techniques, M.Sc. Water Resource thesis, Bangladesh University of Engineering and Technology Huq K A (2001) Water Supply and Sanitation for Dhaka Metropolitan City: Present Status and Future Plan, The Guardian TWDB (2005) Texas Manual on Rainwater Harvesting, Texas

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Potentials, challenges and stakeholders’ responses

Promoting water conservation and recycling techniques through architectural education: students’ acceptance and perception Md Nawrose FATEMI

Introduction In Dhaka, the demand of water is increasing rapidly keeping pace with growth of population, and rise of urbanisation and industrialisation. The recent water supply requirement for the city is about 2250 million litre per day (MLD) against a capacity of supplying 2088 MLD and estimated water demand of 4990 MLD by 2030 (Paul, 2009). So, it is evident that in coming decades, megacity like Dhaka will have to face acute water crisis. To overcome the consequences of water crisis, a few water conservation and recycling techniques such as Rainwater Harvesting (RWH), Decentralised Waste Water Treatment System (DEWATS), installation of water efficient fixtures and appliances, and other similar methods are currently on hand to promote conservation of water. In this case, architects can play a vital role to promote these techniques through their planning and designing techniques for new and existing building projects. So it is very crucial for the architects of Bangladesh to be made aware of their responsibilities by incorporating the concepts of water conservation and recycling from a very elementary level of architectural pedagogy. This paper aims to understand the attitudes of the students towards water conservation and recycling techniques by including this knowledge in the architecture curriculum.

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Rainwater harvesting in Bangladesh

Inclusion of water conservation and recycling techniques in present curricula In Bangladesh, the five years degree programme of Architecture is divided into ten to fifteen semesters or terms with two or three in each year. Architectural curriculum is organised around studio based teaching methods and theories as a supporting aid of design studios. The main intention of the theoretical courses is to form a knowledge base in understanding and solving architectural design problems. As architectural education is multi-disciplinary and multi-dimensional, the theoretical courses involve a wide range of disciplines in the fields of arts, science and engineering (Fatemi et al, 2012).

However, mainly two divisions, theory and sessional courses can categorise the curriculum. Among the sessional courses there are design studios (1 to 10/14), supporting sessionals (e.g. Architectural Graphics, Working Drawings, Computer Aided Design, Field surveys and so on) that act as fundamental tools to support studio courses and additional skills like Photography, Art, Sculpture and Graphic Arts where aesthetic and artistic qualities are nurtured among the students. To give emphasis on design, the ratio of credits between sessional and theory Courses is progressively increased in higher levels. On an average the sessional courses takes up 55 percent and theory courses 45 percent of total credit hours, shown in table 1.

Table 1: Different courses offered from the 9 institutes of Bangladesh with credit points (Begum et al, 2011; modified by author) BUET KU AUST UAP BRAC SUB NSU Sessional courses Design 81 76.5 76.5 81 93 79.5 64.5 studio Graphics 6 6 6 6 4.5 6 6 Working drawing 3 3 4.5 3 3 6 3 Computer 3 3 4.5 6.5 4.5 6 3 Field study & Others 10.5 36 10.5 13 7 11.5 2

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STU

AIUB

79.5

65.5

6

6

9 4.5

3 1.5

13.5

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Potentials, challenges and stakeholders’ responses BUET KU AUST UAP BRAC SUB NSU STU AIUB Theory courses Design 4 9 6 4 3 4.5 6 4+2 theory Language 2 2 6 3.5 6 6 6+1.5 6 History 10+2 17 8 14 12 15 11 18 12 Climate & design 4+2 4 8+2 4+8 6 3 9 3 4+2 Building material 10+2 4 10 4 6 3 6 6 4 Planning 2+4 4 8 2+4 4 3 3 2+2 Humanities 8+10 12 14 4+4 10 9 6 12 13+2 Science 7 8 6 3 6 6 6 6 Mathematics 14 12 13 14 12 9 9 9 10+2 Special 6+20 12+2 10 16+12 12 6 3.5 8+6 courses Prof.

2 2 2 1 3 1.5 2 Practice In the curriculum, water conservation and recycling related topics are included as theoretical knowledge in the section ‘climate and design’ and types of these subjects are mostly like Bio-Climatic Design and Environment Responsive Design, shown in table 2.

Table 2: Courses offered in Dept. of Architecture, UAP and inclusion of water conservation and recycling techniques in present curricula (Prospectus UAP 2011, modified by author) Course Arch 503: Bio-Climatic Design, Offered in 5th year

Arch 533: ED-IV: Environment Responsive

Course Outline Introduction to principles of the philosophies of climatically conscious design. Use of plantations and shading.

Orientation and sun-path analysis.

Using natural resources for ventilation and lighting in an energy conscious way. Designing for environment.

Introduction to the environmental issues. Architecture and Environment. Historical references.

Biosphere and Ecosystem.

Included topic Urban Rainwater Harvesting General information about RWH Principles of RWH Elements of RWH Data collection for RWH Methods of RWH Planning and design Water Efficiency Water Crisis Water Crisis in Dhaka Water Consumption

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Rainwater harvesting in Bangladesh Design, Offered in 5th year

Environmental Impact Assessment (EIA). Comprehending the relationship of building with immediate and distant surroundings.

Pattern Water Conservation Techniques Water Recycling Techniques

These subjects normally involved the teaching of building physics or building sciences, but if they were taught along with the design studio process, then these techniques will be more effectively practiced in future. For this, the projects of the design studio have to be connected with these issues. It is also very important to practice these issues in design studio, because recently it is heard that in the proposed ‘Bangladesh Building Construction Rules’, the issue of rainwater harvesting and ground water recharge is included, which is shown in table 3.

Table 3: Rainwater harvesting and ground water recharge in the proposed Bangladesh Building Construction Rules Rainwater harvesting and groundwater recharge

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1.

Rainwater collection from rooftop and the facilities to use it must be connected as inseparable part of the building. Recharge pit must be constructed to underground recharge the collected rainwater, if the ground coverage by the building is over the 500 square meter limit.

2.

The authority will give preference for issuing the occupancy certificate or renewal application or approval of corrected plan (if necessary), if they incorporated rainwater harvesting system and underground recharge pit before this building construction rule is put into practice.

3.

Necessary numbers of recharge pit will be constructed based on the area of the building or complex.

4.

Rainwater collection, use and underground recharge facilities will have to be approved according to the building code or the specification of the proper authority.

5.

A monitoring cell will be formed jointly by RAJUK and Dhaka WASA. This committee will scrutinise the implementation of the above rules (on rainwater harvesting and ground water recharge from 1-4) and the maintenance, conservation and use of the constructed recharge pit.

Potentials, challenges and stakeholders’ responses

Students’ perception on theoretical knowledge To understand the perception and attitudes of the students towards water conservation and recycling techniques by including this knowledge in the architecture curriculum, data were collected by means of questionnaires. One hundred students (60 students of final year and 40 students of second year) participated in the study.

Result showed that the term ‘Urban Rainwater Harvesting (URWH)’ is a known term to 63 percent of the students (in which 52 students are of final year and 11 students are of second year). This is because that the Institute of Architects Bangladesh (IAB) conducted a CPD course on this issue of rainwater harvesting and ground water recharge recently. And also in the proposed ‘Bangladesh Building Construction Rules’, this issue is addressed, shown in table 3. But it was disappointing that none of them had a clear understanding on this technique. Another important factor was that none of them were aware about ‘Decentralised Waste Water Treatment System’ (DEWATS).

The students (specially the final year students as both the courses are offered in final year) were satisfied to know and appreciated that the topic, ‘Urban Rainwater Harvesting’, is included in the course titled by ‘Bio-Climatic Design’ and the topic, ‘Water Conservation and Recycling Techniques’, is included in the course titled by ‘ED-IV: Environment Responsive Design’. Second year students indicated that they will try to incorporate these techniques in their studio projects, if they have the scope (which is a very good indication to promote water conservation and recycling techniques).

Concluding remarks In conclusion, it is believed that water conservation and recycling techniques has the potential to become a standard practice if the education industry continues to find ways to incorporate this concept both in theory and sessional courses. It has been found by the survey, that students of different years are showing their interest to learn the methods and principles of rainwater harvesting and decentralised waste water treatment. They also indicate to incorporate these techniques in their studio projects. So it can be concluded that the perception and attitudes of the students towards water conservation and recycling techniques is very positive. Therefore, these issues must be included in the architectural curriculum of all institutes in Bangladesh.

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Rainwater harvesting in Bangladesh References Begum J A, Rashid R and Ali M M (2011) Managing Architectural Education in Bangladesh – A Need for a Change, World Review of Business Research, vol. 1, no. 2, pp. 20 - 34 Department of Architecture (2011) Prospectus 2011-2012, University of Asia Pacific, pp. 46 Fatemi M N and Islam N (2012) Implication of Architectural Education for

Promoting Sustainable Built Environment in Bangladesh: Present Trends and Future Potentials, The Proceedings of International Seminar on Architecture: Education, Practice & Research, Dhaka, pp. 259-270 Paul R (2009) Water Security in Dhaka City-An Initiative of Government of Bangladesh, 6th Governing Council Meeting of Asia Pacific Water Forum (APWF), Singapore

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Potentials, challenges and stakeholders’ responses

Rainwater harvesting as an alternative source of water supply for Dhaka city: myth or reality?

Anika TABASSUM

Introduction Water is the most essential element of life which is must for keeping body alive. While the demand for fresh water is increasing day by day everywhere in the world, its supply is decreasing. So, the gap between demand for fresh water and its supply has been ever increasing globally. Dhaka, the capital of Bangladesh is the 19th mega city in the world with a population of over 14 million (World City Information, 2011). Water crisis has become an acute problem faced by the inhabitants of Dhaka city. About 87 percent of this supply comes from groundwater resources and rest 13 percent from surface water. For the huge extraction from the underground water source ground water table is declining day by day. It has been found that the current groundwater depletion rate is 3.52 meter per year (Dhaka Water Supply and Sewerage Authority). Such a fast depletion of the water table will result in intrusion of southern saline water into the groundwater reservoir, depriving this mega city of pure drinking water. Not only water scarcity but also water logging is an acute problem for the inhabitants of Dhaka city that disrupts the traffic movement and create health, hygiene and environmental problem in the life of city dwellers.

In recent years Dhaka city is facing extensive water logging problem during the monsoon (May to October) season. Rainwater harvesting has been emerged as an alternative source of water supply for Dhaka city.

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Rainwater harvesting in Bangladesh In this study potential of rainwater harvesting has been calculated for Kazipara area which is part of Mirpur area of Dhaka City. Kazipara area of Mirpur is one of the areas of Dhaka city facing severe water supply problem. As it is densely populated area, it is difficult for Dhaka Water Supply and Sewerage Authority (DWASA) to provide sufficient amount of water supply and people are suffering from severe water crisis.

Rainwater harvesting system can reduce the dependency on DWASA and partially meet the demand of water in dry season.

Description of the study area Mirpur is one of the renowned areas of Dhaka city situated at north-east part of the city, with an area of 58.66 km2 (22.65 sq miles). It is located at 23.8042째N 90.3667째E. It is bounded by Pallabi Thana to the north, Mohammadpur Thana to the south, Kafrul to the east and Savar Upazila to the west. Kazipara is a part of Mirpur with an area of 5,66,016.8 sq. m. Total population of Kazipara is 41,395 and number of household is 9,787 (BBS, 2011).

Figure 1: Location of the study area

Senpara

Ibrahimpur

Middle Monipur

Shewrapara

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Potentials, challenges and stakeholders’ responses

Research methods In this study secondary data has been collected from various organisations. Rainfall is the most crucial and unpredictable variable to calculate the potential of rainwater harvesting of an area. Rainfall data from 1950 – 2005 have been analysed in this study. From the analysis it was found that average annual rainfall for Dhaka division is about 2,100 mm (Rahman and Akter, 2011). Then to calculate the roof top area GIS database has been used. Total number of structures in Kazipara area has been counted which is about 2,207. From this population, sample size has been determined which is 327 structures at 95% confidence level and 5% confidence interval (Creative Research System, 2010).

Stratified sampling is used to categorise the size of the rooftop area.

The categories are: less than 720 sq. feet, between 720-1440 sq. feet, between 1440 – 2160 sq. feet and more than 2160 sq. feet. Total numbers of buildings among these categories are respectively 868, 862, 335 and 172.

After stratified sampling sample size for each category is 124, 128, 49 and 26 respectively. Total catchment area of 327 structures is 37,353.4 sq. meter. For the roof top of Kazipara area runoff co-efficient is considered as 0.8. All these data have been used in an equation to calculate the potential of rainwater harvesting in Kazipara area.

Results and discussion Calculation of potential of rainwater harvesting Each building roof top area has been calculated from secondary source and surface runoff has been calculated using the equation (i). Then catchment areas are multiplied by the average annual rainfall and runoff co-efficient. Potential of Rainwater Harvesting would be, Potential of rainwater harvesting in each building = A* R* C ………….. (i) A= Catchment area of each building (Area of roof top) R= Average Annual Rainfall of Dhaka city (2,100 mm) C= Coefficient (0.8)

Source: Center for Science and Environment, 2010

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Rainwater harvesting in Bangladesh Table 1: Rainwater harvesting potential for 327 surveyed buildings Roof top area (sq. feet)

Total roof top area (sq. m.)*

Coefficient**

Rainfall (mm)***

Total RWH potential (litre)

Average RWH potential (litre)

Less than 720 Between 720–1440 Between 1440–2160 More than 2160 Total

6,860.52

0.8

2,100

1,15,25,673.6

92,948.98

14,402.72

2,41,96,569.6

1,89,035.70

8,672.61

1,45,69,984.8

2,97,346.63

7,417.55

1,24,61,484.0

4,79,287.85

37,353.4

6,27,53,712

1,91,907.36

*

Source: Dhaka Metropolitan Development Plan: Detail Area Plan 2010, ** Center for Science and Environment 2010, ***Rahman and Akter 2011 From the table 1 it has been observed that with the increase of catchment area rainwater harvesting potential is also increases. So, large plot sizes have more privilege to harvest more rainwater.

Rainwater harvesting potential of total Kazipara area There are total 2,207 buildings in Kazipara. If only roof top area of all buildings have been used as catchment area, then total catchment area is 2,39,343.1 sq. meters. Total rainwater harvesting potential would be, C = 0.8 R = 2,100 mm A = 2, 39,343.1 sq. m Total RWH potential of Kazipara = 2, 39,343.1*0.8*2,100 = 40, 20, 96,341.4 litre per year = 4,02,096.34 cubic meter /year Additional benefits of rainwater harvesting system Rainwater harvesting can be an alternative source of domestic water supply system. This system can be recommended in areas where rainfall is adequate and space is available for storing of rainwater and use it later for non drinking purposes. If the harvested water can be used for toilet flushing and cleaning the house purposes then 30 percent water can be saved from conventional piped water supply system.

28

Potentials, challenges and stakeholders’ responses Table 2: Water requirement for different purposes Use

Consumption (litres/day/person) 5 5 55 20 10 10 30 135

Drinking Cooking Bathing (including ablution) Washing clothes Washing utensils Cleaning the house Flushing of latrines Total for urban areas

Percentage consumption 3.70 3.70 40.74 14.81 7.41 7.41 22.22 100.00

Source: Center for Science and Environment, 2010 If total water consumption is 1, 10,000 litres per month in a building then Water use in Toilet flush

= 1,10,000*22% litre = 24,200 litre per month

Water use in Cleaning purpose

= 1,10,000*8% = 8,800 litre per month

Total water consumption for these two purpose = (24,200+8,800) = 33,000 litres per month Total population of the study area is 41,395 (BBS, 2011). So, total demand of water per year for toilet flushing and cleaning purposes of the study area is 40*41,395*365 = 60,43,67,000 litres per year or 6,04,367 cubic meter per year.

On the other hand the potential of rainwater harvesting at Kazipara area is 4,02,096 cubic meter water per year. Through rainwater harvesting 66.53 percent demand of water for toilet flushing and cleaning purpose can be served.

This will definitely reduce the pressure on DWASA and also partially solve the water scarcity problem. It is also found that through harvested rainwater 20 percent of total water demand can be fulfilled.

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Rainwater harvesting in Bangladesh

Recommendations to promote rainwater harvesting •

In draft proposition of Building Construction Act, 2011, an amendment is added which describe every building should incorporate rainwater harvesting and ground water recharge system.

If the ground coverage is greater than 200 sq. meter then percolation well for ground water recharge should be established.

But within DCC boundary area 81 percent of building is less than 2160 sq feet (200 square meter) in roof top size. So a large number of buildings would be excluded from rainwater harvesting system.

Thus the act needs to be revised.

•

Moreover Dhaka is a densely populated city and many people live in a small building facing water supply problem severely. If rainwater harvesting can be incorporated in small buildings then partial demand of water can be fulfilled. It is found that if 60 percent of the rainfall from roof top can be harvested in Dhaka city, more than 200 MLD water can be available for use (Chowdhury, Rahman, Rahman, Chaki, 2012). So small buildings with an area of less than 200 sq. meter should also be included in the policy to install rainwater harvesting system.

•

Sensitisation and awareness building of mass people is very important to promote rainwater harvesting system in Dhaka city.

Through training, various formal and informal motivation programmes local people should be made aware of rainwater harvesting system.

•

Private sectors especially the real estate companies must be engage in installing rainwater harvesting system.

Concluding remarks Recently rainwater harvesting has achieved great attention in urban areas like Dhaka city to reduce various water related problems such as water scarcity, water logging etc. Government has already taken some initiatives to promote rainwater harvesting not only in institutional building but also in residential buildings of Dhaka city. But there is no such background study which provides an accurate calculation of the potential of rainwater harvesting in typical densely populated residential area, constraints of this system and most importantly perception of local people whether they are interested to install this system in their buildings. This study might assist the decision maker to understand the

30

Potentials, challenges and stakeholders’ responses actual scenario of potential of rainwater harvesting in a densely populated residential area and find some solutions to overcome the constraints and transform water supply and its management sustainable.

Acknowledgement Dr Ishrat Islam, Professor, Department of Urban and Regional Planning, Bangladesh University of Engineering and Technology (BUET) Fuad Hasan Ovi, Planner, Graduated from Department of Urban and Regional Planning, Bangladesh University of Engineering and Technology (BUET) Md Abu Hanif, Planner, Graduated from Department of Urban and Regional Planning, Bangladesh University of Engineering and Technology (BUET) Maharam Dakua, Research Associate, ITN-Centre, Bangladesh University of Engineering and Technology (BUET)

References BBS (2011) Population Census: National Report, Bangladesh Bureau of Statistics, Dhaka BWDB (1999) Hydrological Network (SW), BWDB, UNDP, United Nations Department for Development Support and Management Services Project: BGD-88-054 WRIS Center for Science and Environment (2010) A Water Harvesting Manual For Urban Areas Case Studies from Delhi, Center for Science and Environment, New Delhi, India Chowdhury S Q A, Rahman M, Rahman S M and Chaki T (2012) Artificial

Recharge to Dhaka Aquifer from Rainwater is Inevitable for Aquifer Environment and Water Supply, Paper presented at the Bangladesh

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Rainwater harvesting in Bangladesh Convention on Rainwater Harvesting 2012 Conference, Dhaka, Bangladesh Creative Research System (2010) Sample Size Calculator, Accessed on June 15, 2012, website: http://www.surveysystem.com/sscalc.htm DAP (2010) Preparation of Detailed Area Plan (DAP) for Dhaka Metropolitan Development Plan (DMDP) area: Location-10, Final Plan Report, RAJUK, Dhaka, Bangladesh DWASA (2011) Annual Report 2010-2011, Dhaka Water Supply and Sewerage Authority, Dhaka.

IWFM (2008) Climate Change Research Characterizing Long-term

Changes of Bangladesh Climate in Context of Agriculture and Irrigation, Climate Change Cell Department of Environment, Ministry of Environment and Forests Component 4b Comprehensive Disaster Management Programme, Ministry of Food and Disaster Management, Bangladesh Rahman M M and Akter K S (2011) Climate Change Pattern in Bangladesh and Impact on Water Cycle, ITN- BUET, Center for Water Supply and Waste Management, Dhaka, Bangladesh World City Information (2012) World Megacities 2011, Retrieved on June 19, 2012 from website: http://www.city-infos.com/world-megacities/ Vishwanath S (n.d) Rainwater Harvesting in Urban Areas, Bangalore, India

32

Potentials, challenges and stakeholders’ responses

Artificial groundwater recharge through rainwater harvesting in urban residential areas: a study on Niketan area of Dhaka city SA NAHIAN, Kazi Rashed HYDER & Shahnoor HASAN

Introduction Dhaka, the capital of Bangladesh, has a population of over 13 million with an ever-increasing population rate of over 5 percent (WWF, 2009; The Sydney Morning Herald, 2010; The Daily News Monitoring Service, 2011). Due to such rapid growth, the city is facing stern pressure to supply the potable water over the last decade. Approximately 90 percent of the city’s municipal water supply comes from ground water level (ibid, 2011).

Institute of Water Modelling (IWM) and Dhaka Water Supply and Sanitation Authority (DWASA) have projected that only about 39.5 percent of city’s water demand would be fulfilled in the year around 2030 against the estimated demand of approximately 4990 million L per day (ibid, 2011). It has also been estimated that groundwater sources would contribute about 87 percent out of the 39.5 percent.

However, according to various studies, the city’s ground water table has been depleting at an alarming rate. According to a study conducted by

33

Rainwater harvesting in Bangladesh the IWM, the city’s groundwater level has been falling by 3 m per year, which now stands approximately 60 m down below the surface compared to 10 m in 1970 (Biswas et al, 2010). In another study of Bangladesh Agricultural Development Corporation (BADC), the level has depleted down to 61.18 m below the surface in the Dhaka city alone (ibid, 2010). Also, due to severe electricity shortage and rising consumption charge, the option of groundwater extraction has become difficult and costly (The Sydney Morning Herald, 2010; Islam et al, 2010).

Potential of rainwater harvesting The increased rate of urbanisation and illegal encroachment has reduced the amount and volume of surface water bodies around Dhaka city which has further aggravated the situation (Seraj, 1994; Tawhid, 2004).

In addition, the surface water from the river- Balu, Shitalakhya, Turag and Buriganga has become so highly polluted that the water is beyond treatment. The quest for water has forced people to use contaminated sources of water, triggering a massive diarrhoea outbreak in every summer, mostly affecting children (The Sydney Morning Herald, 2010; Searchlight South Asia, 2010).

On the other hand, during monsoon, the suffering of people has been found to increase with a contrasting problem, which is, water logging (Alam and Rabbani, 2007). The city becomes virtually submerged under water in almost all places whenever rain drenches the city for some time (Seraj, 1994). Even relatively low intensity of rainfall causes inundation of various scales in the low-lying, built-up areas several times a year (Tawhid, 2004; Apirumanekul and Mark, 2001). During inundation, the depth of water reaches as much as 40-60 cm, causing serious threats to the economy, health and well-being of the people. A report of DWASA has showed that during the water logging in September 2004, 250 city schools and 681 garment industries were affected (Tawhid, 2004). The garments sector alone lost 632 billion BDT (ibid, 2004). Moreover, after being water-logged, the damaged road network needed 12.8 billion BDT for reconstruction (Seraj, 1994).

In this context, artificial ground water recharge through rainwater can be an ideal solution for the potable water supply in the city (UN-HABITAT, 2013). Rainwater harvesting offers a better solution in areas where inadequate ground water supply and surface water resources are either lacking or are insufficient (ibid, 2013). A rainwater harvesting system comprises components of various stages - transporting rainwater

34

Potentials, challenges and stakeholders’ responses through pipes or drains, filtration, and storage in tanks for reuse or recharge (ibid, 2013). The artificial recharge through rainwater can be done by using any suitable structures like dug wells, bore wells, recharge trenches and recharge pits11. The structures required are simple and economical (ibid, 2013). Construction, operation, and maintenance are also not labour intensive. Existing structures like wells, pits and tanks can also be modified to be used as recharge structures thereby eliminating the need to construct any new structures (ibid, 2013). The recharge of groundwater would raise the water levels in wells and bore wells that are drying up as well as reduce the soil erosion as the surface runoff is reduced (ibid, 2013). It would also decrease the choking of storm water drains and flooding of roads.

The underground formation or aquifer status is a very significant analytical variable for successful completion of recharge because its character varied from location to location or region to region (UNHABITAT, 2013; CSE, 2013). Sandy layer is better for recharge as opposed to other types of soil layers, such as bedrock, silt, clay, sand, gravel etc. To calculate annual rainwater harvesting potential, parameters, such as, average annual rainfall (R), area of the catchment (A), and runoff coefficient (C) are required (UN-HABITAT, 2013). The potential is calculated with the following equation: Annual water harvesting potential = A x R x C (UN-HABITAT, 2013; CSE, 2013).

The rate of recharge, in comparison to runoff, is a critical factor.

However, the recharge rate needs to be assumed, since accurate recharge rates are not available without detailed geo-hydrological studies. The capacity of recharge tank is usually designed to retain runoff of peak rainfall intensity for at least 15 minutes (UN-HABITAT, 2013; CSE, 2013).

The annual average rainfall of Dhaka city has been projected at 2150 mm from the city’s rainfall data over 30 years from 1975 to 2015 (BMD, 2004). Approximately, 1680 mm of the annual average rainfall has been found to precipitate over 5 months from May to September (ibid, 2004).

In addition, maximum average rainfall occurs during the month of July, the amount of which is almost 400 mm (ibid, 2004). The peak hourly rainfall of the city is 100 mm (based on rainfall frequency of 25 years) and 15 minutes’ peak rainfall is 25 mm/hour or 0.025 m/hour (ibid, 2004).

Recently, IWM has estimated that around 1,49,160 million L of water can be harvested during rainy season (Islam et al, 2010). This would reduce

35

Rainwater harvesting in Bangladesh the dependency on groundwater at least during the six months of monsoon. In addition, one-meter rise in water level due to the harvesting would save 0.40 kilowatt hour of electricity in the load shedding stricken city (UN-HABITAT, 2013). To put the system into practice, the government has been going to amend the Building Construction Rules 2008, making the provision of rainwater harvesting mandatory for all new houses in Dhaka Metropolitan area (The News Today, 2011).

Research methods This study has been undertaken in one of the populous residential areas of the city. One of the major objectives of the study was to assess the potentiality and effectiveness of artificial groundwater recharge through rainwater harvesting in residential areas of Dhaka City. The study has been undertaken in the C block portion of Niketan, one of the populous residential areas of the city. All the seven blocks of the area are well constructed and the C block portion is mostly residential. The study area has 128 land plots, each with an average area of 334.5 m2.

Keeping the building construction in mind, 60 percent of each plot, equivalent to 200.7 m2, has been considered as paved area. The other 40 percent, equivalent to 133.8 m2, has been considered as unpaved area. Sandy layer has been found below the 18.29 m from the ground level in the study area. The infiltration rate of the soil in the area has been considered to be of 1.2 m3/hour.

The study has been conducted through primary data. Also, it was compiled through the study of various literatures available on the concerned subject. To that end, a comprehensive literature review was undertaken. Microsoft excel has been used for data analyses.

Results and discussion For the paved portion, rainwater harvesting potential for each plot in the designed system has been found to be of 3,45,204 L, with the catchment area (A) of 200.7 m2, annual average rainfall (R) of 2.15 m, and runoff coefficient (C) for paved area of 0.80. The rainfall intensity in this case turns out to be of 4264.87 L per hour for the 200.7 m2 paved area with peak rainfall of 0.025 m/hour for 15 minutes.

36

Potentials, challenges and stakeholders’ responses For the unpaved area, rainwater harvesting potential for each plot has been found to be of 86,301 L, with the catchment area (A) of 133.8 m2, annual average rainfall (R) of 2.15 m, and runoff coefficient (C) for unpaved area of 0.30. The rainfall intensity has been found to be of 1003.5 L per hour for the 133.8 m2 unpaved area with peak rainfall of 0.025 m/hour for 15 minutes.

Table 1: Relevant data of the harvested rainwater Month January February March April May June July August September October November December

Rainfall (m) 0.0078 0.0217 0.0648 0.1442 0.2962 0.347 0.3951 0.3003 0.3442 0.1846 0.0337 0.0098

Harvested Rainwater (L) From paved area 1565.46 4355.19 13005.36 28940.94 59447.34 69642.9 79296.57 60270.21 69080.94 37049.22 3763.59 1066.86

From unpaved area 1043.64 2903.46 8670.24 19293.96 39631.56 46428.6 52864.38 40180.14 46053.96 24699.48 4509.06 1311.24

Collected data (see Table 1) indicates that it is possible to harvest rainwater from both paved and unpaved areas all year round. This would reduce the pressure on underground reservoir as well replenishing the depleting water table. With the maximum amount of rainfall in July, the harvested rainwater reaches a maximum of 1,32,160.95 L per plot area.

Based on the calculations, it has also been found that a siltation tank of 2m x 1m x 1m and a percolation pit of 1m x 1m x 1m would be required to recharge the total harvested water. For recharge, a polyvinyl chloride (PVC) pipe with a diameter of 0.15 m needs to be installed through boring. A 10 m long strainer also needs to be placed. For filtration, ž downgraded gravel materials with a thickness of 0.75 m could be used.

With the sand infiltration rate of 0.25 L/hour/m2, approximately 42,408 L of harvested water will be filtered and recharged per hour.

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Rainwater harvesting in Bangladesh

Concluding remarks The study indicates that artificial groundwater recharge is a sustainable and cost-effective proposition for the residential areas of Dhaka city.

The calculation shows that the recharged water would contribute in reducing the declination of water table and water stagnancy in study area. This method could be easily implemented in other densely populated areas of the city. Furthermore, the operating costs of the recharge system are low in comparison to the cost of treating river water for direct use. However, authorisation for artificially recharging the aquifer should be given only if the hydro-geological situation, environmental condition and the recharge-water quality permit injection, percolation or infiltration of water by artificial means into aquifers for storage and retrieval.

Acknowledgement The authors acknowledge Prof. M. Ali Hossain, Head, Department of Environmental Science, Independent University, Bangladesh, and Ms. Hasin Jahan, Program Director, WaterAid, Bangladesh.

References Alam M and Rabbani M G (2007) Vulnerabilities and responses to climate change for Dhaka, Environment and Urbanization, 19(1), pp. 8197 Apirumanekul C and Mark O (2001) Modelling of Urban Flooding in Dhaka City, Asian Institute of Technology, Accessed on April 2012, Available: http://www.dhigroup.com/upload/publications/mouse/Apirumanekul_Mod elling_of_Urban.pdf Biswas S K, Mahtab S B and Rahman M M (2010) Integrated Water Resources Management Options for Dhaka City, Proceedings of International Conference on Environmental Aspects of Bangladesh 2010, pp. 179-181, Accessed on January 2013, Available: http://benjapan.org/iceab10/47.pdf

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Potentials, challenges and stakeholders’ responses

BMD (2004) Bangladesh Meteorological Department CSE (2013) Design of Groundwater Recharge Structures, Centre for Science and Environment, Accessed on February 2013, Available: http://www.rainwaterharvesting.org/Urban/Design_Recharge.htm Islam M M, Chou F N F and Kabir M R (2010) Feasibility and

acceptability study of rainwater use to the acute water shortage areas in Dhaka City, Bangladesh. J. of Nat Hazards, 56, pp. 93-111 Seraj S M (1994) Disaster Management in Metropolitan Dhaka in

Disaster Management in Metropolitan Areas for the 21st Century, Proceedings of the IDNDR Aichi/Nagoya International Conference, pp.

547-554, Accessed on April 2012, Available: http://salekseraj.com/C40.pdf.

Searchlight South Asia (2010) Accessed on January 2013, Available: http://newsletters.clearsignals.org/Intellecap_Apr2010.pdf Tawhid K G (2004) Causes and Effects of Water Logging in Dhaka City, Bangladesh, KTH Royal Institute of Technology, Accessed on April 2012, Available: http://www2.lwr.kth.se/Publikationer/PDF_Files/LWR_EX_04_45.PDF The Daily News Monitoring Service (2011) Groundwater Level Jumped Down Radically in Dhaka, Accessed on January 2013, Available: http://bangladesh-web.com/view.php?hidRecord=353406 The News Today (2011) Rainwater Harvesting to be Made Mandatory in Capital, Accessed on February 2013, Available: http://www.newstoday.com.bd/index.php?option=details&news_id=3513 6&date=2011-08-03.

The Sydney Morning Herald (2010) Bangladesh Water Shortage Sparks Protest, Accessed on January 2013, Available:

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Rainwater harvesting in Bangladesh http://news.smh.com.au/breaking-news-world/bangladesh-watershortage-sparks-protest-20100407-rrxn.html UN-HABITAT (2013) Beneficiaries & Capacity Builders: Rainwater Harvesting and Utilisation, United Nations Human Settlements Programme, Accessed on January 2013, Available:http://www.hpscste.gov.in/rwh/Blue_Drop_Series_02_Capacity_ Building.pdf.

WWF (2009) Mega-Stress for Mega-Cities: A Climate Vulnerability Ranking of Major Coastal Cities in Asia, World Wide Fund for Nature, Accessed on January 2013, Available: http://www.city-infos.com/list-ofmegacities-2011

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Potentials, challenges and stakeholders’ responses

Promoting urban rainwater harvesting: policy support, gap and initiatives Syed Azizul HAQ

Introduction Bangladesh is a predominantly agricultural economy based deltaic land where industrialisation is also growing in a relatively faster pace to reach the group of middle income countries soon. Both these two sectors consume considerable volume of water mainly from underground due to having little reliance on surface waters for its unacceptable quality or quantity or both during the time of need.

Over population is another factor which is resulting in unemployment thereby causing migration from rural to urban centres. Most of the urban centres are getting over populated and their boundaries are expanding wider. Growing population in the urban centres is creating pressure on infrastructural development, where building development is the dominant sector amongst all others. Water is the primary need for these building users. In almost all the urban centres situation of wholesome water availability is narrowing with the passage of time. In urban centres, water supply rate could not be maintained as per the demand for various reasons including surface water pollution and

41

Rainwater harvesting in Bangladesh ground water depletion. In most of the city centres, water availability from both the surface and underground sources is becoming either limited or costly which might become nearly impossible to avail eventually.

In such water scenario, a third option is envisaged. In Bangladesh where average rainfall varies from 1200 mm in the extreme west to over 5000mm in northeast (WB,2000), rainwater harvesting is considered to be the next option (Haq, 2005) to look into. In urban perspective, rainwater harvesting appears in different perception than in rural perspective. Unplanned urbanisation and unregulated building development are two burning issues deepened the crisis in building development activities. Promoting rainwater harvesting might face challenges due to absence of supporting policy, regulations, guidelines etc. In this paper existing policy supports or gaps therein are searched out with a view to promote rainwater harvesting in buildings in urban context and the initiatives in national level are reviewed to find out the ways forward.

Related policies to promote RWHS Public policies are guide lines in broader perspective, incorporating achievable course or plan of action providing obstacles to overcome and opportunities to utilise that relate to a given environment and targeting to reach a goal or realise some objectives or purposes. The objectives or goals of these policies are basically for economic growth, social and environmental safety etc.

With a view to promote rainwater harvesting in the country an exclusive policy in this regard is yet to be formulated. But there are several other policies related to water and environment in which rainwater harvesting is not highlighted excepting a few. The water related public policies are as follows: 1. National Water Policy 1999 2. National Policy for Safe Water Supply and Sanitation 1998 There are also many other policies as below, which also relates to water and environment.

1. National Environmental Policy 1992 2. National Forestry Policy 1994 3. National Fisheries Policy 1998

42

Potentials, challenges and stakeholders’ responses 4. National Agricultural Policy 1999 and 5. Industrial Policy 1999 Among these policies, in National Water Policy 1999, policies in various aspects are set with a view to improve water resource management and environmental protection (MoWR, 1999). To address the prevailing situation in water supply and sanitation with respect to water availability both in urban and rural areas, government has taken the policy to facilitate availability of safe and affordable drinking water supplies through various means, including rainwater harvesting and conservation. Furthermore in article 4.6 of section b of this policy, policies have been narrated to preserve natural depressions and water bodies in major urban areas for recharge of underground aquifers and rainwater management. In article 4.7 of section b, it is mentioned that groundwater development for irrigation would be encouraged by both the public and the private sectors subject to regulations that might be prescribed by the government from time to time.

In article 4.15, the importance of research and information management is emphasised with a view to inform its stake holders like specialists, planners, professionals, politicians and the general public to take proper decision about appropriate technology and options to meet policy goals and make them aware of their significance and impact. In this regard the government has taken policy to strengthen and promote the involvement of public and private research institutes and universities to develop and disseminate appropriate technologies for conjunctive use of all waters including rainwater (MoWR, 1999).

In national policy for safe water supply and sanitation 1998, in the definition of safe water supply it is said that “Safe water supply means withdrawal or abstraction of either ground or surface water as well as harvesting of rain-water; its subsequent treatment, storage, transmission and distribution for domestic use� (MoLGRD, 1998).

Gaps in policies with respect to rainwater harvesting From the review of the policies mentioned earlier it is understood that rainwater harvesting is not well addressed as it would be. It may be due to the fact that at the time of policy formulation water scarcity and its future consequences could not be well presumed or studied. The situation or cases where there might have been scopes of mentioning use of rainwater in those policies are discussed below.

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Rainwater harvesting in Bangladesh

In article 4.3 section c of national water policy 1999, it is said that “For sustaining rechargeable shallow groundwater aquifers, the Government will regulate the extraction of water in the identified scarcity zones with full public knowledge� (MoWR, 1999). Here promotion of ground water recharging by rainwater could be introduced.

In article 4.8, there might have been a clause of mentioning use of rainwater and ground water recharging for the industries primarily based on ground water for its production or manufacturing and industrial process.

In article 4.11, development of artificial or manmade water recreation facilities depending exclusively on underground water could be discouraged. In limited cases, these could be allowed to develop incorporating rainwater harvesting and recycling of wastewater.

In article 4.12, protection and preservation of environmental resources particularly ground water resources could be emphasised more by putting provision of encouragement in adopting alternative options of water collection like rainwater harvesting and recycling of wastewater etc.

In article 4.14 section g, incentives for rainwater harvesting could be mentioned along with other steps mentioned to cover almost all sustainable and practicing options.

In national policy for safe water supply and sanitation 1998, there is no provision of rainwater harvesting in policies for urban water supply.

Here policy could be taken incorporating provisions of rainwater harvesting in buildings or other establishments where water could not be supplied satisfying their rational demand for which permission is given for ground water abstraction individually.

Initiatives at National level Rainwater harvesting is a proven old technology to be reintroduced whenever necessary and where applicable. It should not only be started practicing at the advent of surface and underground water crisis, but to be wise, much ahead of sensing the crisis. In this context, initiatives at national level are not lagging far behind. The initiatives in broader perspective are mentioned below.

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Potentials, challenges and stakeholders’ responses

In 2000, Prime Minister had instructed “Buildings under government owned projects shall had to be designed in such a way that rainwater could be stored in and be used subsequently” (GoB, 2000). Public Works Department (PWD), under the Ministry of housing and public Works (MoHPW), in collaboration with the Department of Architecture (DoA), published a “Manual on Rainwater Harvesting” in Bengali in February 2002. At present in some public projects, rainwater harvesting has been incorporated in a very limited manner.

Bangladesh Construction Regulation (BCR) 2006, 2007 and 2008, promulgated by Rajdhani Unnayan Kartipakkha (RAJUK), allowed to build buildings covering 50 to 67.50 percent of the plot area and instructed to keep 50 percent of the rest open area as green space (RAJUK, 2008). This provision for exclusive green space is to facilitate percolation of rainwater into the ground directly. In the upcoming revised BCR, regulations for rainwater harvesting are being included.

The rule would be mentioning that in buildings having ground coverage more than 200 square meter shall have to incorporate ground water recharging system and for every 1000 square meter or part thereof shall have one recharge well (Personal Interview).

In 1993 Bangladesh National Building Code (BNBC 93) has been published. In its building service part there is a chapter titled “Sanitary drainage” which included some guidelines related to rainwater storage and mostly about drainage of storm water (HBRI and BSTI, 1993). Now the process of updating BNBC 93 is near completion. In this updated BNBC there will be a dedicated chapter on rainwater management, describing the guidelines for rainwater harvesting (Haq, 2013).

Institutional challenges to address water crisis In Bangladesh abundance and scarcity both are reality regarding availability of water irrespective of quality. Availability of usable water in the dry periods is near invincible challenge to be overcome.

Establishing rainwater as the alternative source of water supplementing supplied water in urban areas is the appropriate option to manage those crisis periods. Various challenges are to be faced in various tiers right both in national and individual level to establish rainwater harvesting system in urban sector. The national level challenges are as follows:

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Rainwater harvesting in Bangladesh Urban water supply authorities can hardly satisfy the domestic need of water but lag behind to fulfil the reasonable urban water demand and far behind the water requirement needed for a healthy urban development according to World Health Organization (WHO), who considers 1000 litre per person per year to be a necessary amount of water (Cunningham and Cunningham, 2003). Augmenting surface water resources through periodical dredging of rivers ensuring its environmental flow and reclaiming illegally encroached land of surface water bodies particularly within urban boundaries is the biggest challenge. Pollution control through strict enforcement of industrial effluent management regulations and developing proper urban sewer system is the next bigger challenge. Development of water supply infrastructures is another concurrent big challenge. In these situations realising fair price of water from the consumers, ensuring supply of adequate quantity and acceptable quality of water, in near future is almost absurd. Whenever consumers will be tried to get managed through overcoming these challenges and fair price would be asked therefore, only then they would be feeling the real price of water, which would relatively be higher and then will be easily convinced to install rainwater harvesting system.

Replenishment of depleted underground water is also a tough challenge. Abstaining from abstraction of ground water might be alternative way to. But in the situation when the drinking water demand is fulfilled by withdrawing about 95 per cent ground water (Ahmed et al 2001), it would be a tough challenge to bring it down to about 30 per cent abstraction (NA, 2012) in near future, as planned by Dhaka Water Supply Authority.

In an over populated country majority of the urban areas are developed in a very unplanned and crammed manner leaving very little open spaces all around. Furthermore majority of the buildings are developed violating construction regulations and in a non-engineered way. In such built environment incorporation of rainwater harvesting system would be facing big challenges particularly in construction of underground rainwater storage system.

The challenges so far discussed, all are the fall out of poor governance of the concerned authorities and the individuals behind if any.

Concerned authorities are mostly found to be engaged in multi functional activities and headed by out sourced officials either deputed or on contractual service having little prior experience in the relevant field. Incapacitation of these authorities is the weakest part of their

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Potentials, challenges and stakeholders’ responses governance which is graved deep due to mal practices and corruption.

Urban water supply authorities and municipalities those are mandated for water supply is also responsible for sewage management which is of different dimension in terms of planning, design, maintenance and operation perspective. In addition municipalities are engaged in various others service oriented activities. In this situation institutional reforming aiming at developing sustainable water supply in the urban areas would be a big challenge.

Recommendations to promote rainwater harvesting With a view to promote urban rainwater harvesting in Bangladesh this issue need to be well addressed and supported in the policies related to water and environment. The national water policy 1999, which has endorsed importance of rainwater utilisation in some of its articles, should be reviewed and revised in the light of bridging the gaps pointed herein by incorporating rainwater harvesting in achieving various targets set in this policy. The national policy for safe water supply and sanitation 1998 should also be reviewed and revised accordingly. In future exclusive policy on rainwater harvesting may be formulated for better utilisation of this potential source of water.

Additionally following suggestions are put forward.

To promote rainwater harvesting system, in all the government projects at water scarce areas, incorporation of rainwater harvesting system needs to be ensured first. Then in private projects in particular areas, incorporation of rainwater harvesting system has to be made mandatory in phases. At first in Dhaka metropolitan area, in all public and private development projects, incorporation of rainwater harvesting have to be made mandatory (Haq, 2006).

A National urban water supply authority could be established to provide wholesome water for meeting the water demand of all urban centres. In due course with the economic development that authority might be upgraded into national water supplying authority for supplying water to every corner of the country. This authority will plan pragmatic strategies and take all necessary measures to manage the crisis of water.

Depending upon the surface and ground water condition this authority will take steps where and how and what other supplementing options like rainwater harvesting system can be introduced in the water supply management. This authority will also formulate guidelines for

47

Rainwater harvesting in Bangladesh installation of ground water recharge wells with respect to demand for ground water and its prevailing situation.

The law makers, policy makers, officials and related all others have to be sensitised and convinced regarding the importance of rainwater harvesting, in the water resource management, through various formal and informal awareness creation initiatives. Establishment of a new regulatory authority for building development is necessary to regulate the building development activities according to BNBC along with other related activities. Since buildings cover the major portion of all the urban infrastructures so rainwater harvesting in buildings would be a huge volume of job which need to be regulated for its proper design, installation, operation and maintenance. In this case building regulatory authority (in the case of Dhaka, it could be RAJUK) would be regulating those functions of rainwater harvesting system in buildings.

Concluding remarks In the emerging situation of water crisis in areas where considerable rain is available, rainwater harvesting is the next option as source of water even in urban areas. Promoting urban rainwater harvesting in urban areas needs both policy and technological support. Though the existing water related policies endorse importance of rainwater harvesting but this option needs more support in order to reach the targeted goals in water sector. Exclusive policy on rainwater harvesting would be the best approach while reviewing and revising the existing water related policies incorporating more provisions of rainwater harvesting and bridging the gaps in these contexts, might satisfy the immediate need. In this respect institutional development and capacity building are also required for the purpose.

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Potentials, challenges and stakeholders’ responses References Ahmad Q K, Biswas A K, Rangachari R and Sainju M M (2001) Ganges –

Brahmaputra – Meghna Region: A Framework for Sustainable Development; University Press Limited: Dhaka, Bangladesh Cunningham W P and Cunningham M A (2003) Principals of Environmental Science, Inquiry and Applications, Tata McGraw-Hill Publishing Company Ltd, page 231, New Delhi GoB (2000) Brishtir pani shangrakkhan o baybohar proshonge nirdeshaboli; Prime Ministers Secretariat: memo no. 69, 39, 17,0,0,6,2000-371(500), date 10 August, Government of Bangladesh, Dhaka Haq S A (2005) Rainwater Harvesting: Next Option as Source of Water, Proceeding of Third Annual Paper Meet and International Conference on Civil Engineers, IEB, Dhaka Haq S A (2006) Rainwater Harvesting: Save Demagnetizing Dhaka of Hopes, World Habitat Day Souvenir, Bangladesh Institute of planners and Center for Urban Studies, Dhaka Haq S A (2013) Part 8 Chapter 7, Rainwater Management, Presentation in the workshop on the Draft of updated Bangladesh National Building Code 1993, Bangladesh University of Engineering and Technology: 2123March, Dhaka HBRI (Housing and Building Research Institute) and BSTI (Bangladesh Standard Testing Institute (1993) National Building Code 1993, Dhaka MoLGRD (1998) National Policy for Safe Water Supply & Sanitation 1998, Ministry of Local Government, Rural Development, Government of the People’s Republic of Bangladesh, Dhaka MoWR (1999) National water policy, Ministry of Water Resources, Government of the Peoples Republic of Bangladesh, Dhaka

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RAJUK (2008) Dhaka Mohanagar Imarat (Nirman, Unnayan, Shangrakkhan O Aposharon) Bidhimala, Building Development Rules, Rajdhani Unnayan Kartipakkha, Dhaka The Daily New Age (2012) Water crisis will not end soon: WASA chief, A Staff report, 10 July issue, Dhaka World Bank (2000) Bangladesh: Climate Change and Sustainable Development, Bangladesh Report No. 21104-BD, Rural Development Unit, South Asia Region, World Bank

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Potentials, challenges and stakeholders’ responses

Promoting urban rainwater harvesting through educational institutes: a case study of Independent University, Bangladesh Shahnoor HASAN, Kazi Rashed HYDER & Hasin JAHAN

Introduction United Nations Human Settlements Programme (UN-HABITAT) has identified rainwater harvesting system (RWHS) as a long-term and effective solution to decrease the demand-supply disparity of water in urban areas (WWF, 2009; Islam et al, 2010). RWHS offers an ideal solution in urban cities where inadequate ground water supply and surface water resources are either lacking or are insufficient (UNHABITAT, 2012). Harvested water could be used immediately, thus saving city level supplies of groundwater for a future date (ibid, 2012).

In addition, a decision could be taken to store it for later use, for instance, during water shortage days.

Typically, a RWHS consists of three basic elements: the collection system, the conveyance system, and the storage system (ibid, 2012).

Collection systems can vary from simple types within a household to bigger systems where a large catchment area contributes to an impounding reservoir from which water is either gravitated or pumped to water treatment plants (ibid, 2012). The categorisation of rainwater harvesting systems depends on factors like the size and nature of the

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Rainwater harvesting in Bangladesh catchment areas and whether the systems are in urban or rural settings (ibid, 2012).

The process of collecting rainwater harvesting encompasses catching rainwater using simple techniques such as jars and pots as well as engineered techniques; directing it to an appropriate location; and filtering it if required (UN-HABITAT, 2012). The rainwater collected can then be stored for direct use and/or recharged into the groundwater (ibid, 2012). Water collected can be stored for four to five months without bacterial contamination, thus possibly reducing the incidence of diarrhoea (Biswas et al, 2010). First flush of rainwater is usually discarded to ensure that runoff from the first spell of rain is flushed out and does not enter the system (UN-HABITAT, 2012). This is done since the first spell of rain usually carries a relatively larger amount of pollutants from the air and catchment surface (ibid, 2012).

The recharge through rainwater can be done by using any suitable structures like dug wells, bore wells, recharge trenches and recharge pits (UN-HABITAT, 2012). Existing structures like wells, pits and tanks can also be modified to be used as recharge structures, thereby eliminating the need to construct any new structures (ibid, 2012). The recharge of groundwater would raise the water levels in wells and bore wells that are drying up as well as reduce the soil erosion as the surface runoff is reduced (ibid, 2012). It would also decrease the choking of storm water drains and flooding of roads during monsoon.

The structures required for RWHS are simple, economical and can be built to meet almost any requirements (UN-HABITAT, 2012).

Construction, operation, and maintenance are not labour intensive. The harvested water can also be used for non-potable uses such as toilet flushing, clothes washing, gardening, and landscape irrigation, which require large amount of water every day (ibid, 2012). Moreover, the role of rainwater harvesting as sources of supplementary or emergency water supply is becoming increasingly important especially in view of increased climate variability, the possibility of greater frequencies of droughts and floods, and crisis in urban sources of water (ibid, 2012).

Initiatives and challenges for promoting RWHS in Bangladesh To put the system into practice, the government of Bangladesh is going to amend the Building Construction Rules 2008 making the provision of RWHS mandatory for all new houses in Dhaka Metropolitan area (The News Today, 2011). It has been estimated that RWHS could supply more

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Potentials, challenges and stakeholders’ responses than 15 percent of Dhaka’s thirst with an annual average rainfall of 2,150 mm (Islam et al, 2010; BMD, 2004). In addition, one-meter rise in water level due to the harvesting would save 0.40 kilowatt hour of electricity in the load shedding stricken city (UN-HABITAT, 2012).

However, there is a lack of knowledge dissemination and awareness from the users’ end. In this context, various educational institutions should come forward with their collective force of teachers and students to make people familiar with RWHS. Towards the goal, two renowned institutions WaterAid, Bangladesh, a leading Non Government Organization (NGO) promoting safe water, sanitation and hygiene education and Independent University, Bangladesh (IUB), a renowned private university have come forward to set up RWHS at the university’s premises to minimise groundwater extraction. The initiative focuses on the key role the educational institutes can play in promoting RWHS, especially to the students who come from various strata of the society.

Brief description of the IUB project Founded in 1993, IUB is one of the oldest private universities in Bangladesh. IUB has approximately more than 4500 undergraduate and graduate students with 410 management and faculty members till May 2012. The student population has been projected to grow at 10 percent annually. At the end of 2010, IUB has moved to its brand new US $ 30 million state of the art campus in Bashundhara area, Dhaka. Since 2010, IUB has been spending a large amount of money to extract groundwater using generator and pumps to meet the requirement.

The RWHS designed at IUB has both the storage and recharge facilities.

The total catchment area includes some portions of the rooftop of academic building and a portion of the rooftop of the gymnasium wing.

It has been estimated that approximately 1.208 million litres of rainwater will be potentially harvested per annum with an annual storage and recharge potential of approximately 0.444 million litres and 0.764 million litres respectively.

For storage, a portion of rooftop of the academic building with an area of 295 m2 has been considered as catchment. At first, the captured rainwater is passed through a 3.66m1.22m1.52m de-siltation chamber with the capacity of 6800 L. The water then flows into a 1.52m1.22m1.52m filtration chamber with the capacity of 1665 L. For filtration, ¾ downgraded gravel materials with a thickness of 0.76m have been used. After passage through the de-siltation and the filtration

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Rainwater harvesting in Bangladesh chambers, the water is stored in the existing reservoir situated on the rooftop of administration building. The use of existing reservoir with the capacity of 50000 L has reduced the additional cost of constructing any new storage device. In addition, 590 L of rainfall is discarded as first flush.

The stored water is used for toilet flushing and for other cleaning usages including ablution. The demand for water in the 8 toilet blocks used by approximately 410 personnel has been estimated to be about 61500 L per month.

Figure 1: De-siltation and filtration chambers and the water reservoir

De-siltation & Filtration chamber

Reservoir

Filtration chamber De-siltation chamber

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Potentials, challenges and stakeholders’ responses Figure 2: Monthly demand and harvest of water in IUB 140000 120000 R ainfall(m)

100000

C atc hment (m2)

80000

Demand

60000

Harves ted R ainwater(L ) S torage(L )

40000 20000

Defic ienc y (L )

r

r

be

be

em

em

ec

ov

S urplus (L )

D

N

ct ob

O

te m ep

S

er

r

t

be

us

ly

ug A

ne

Ju

Ju

pr il

M ay

A

ry ua

M ar ch

nu

br

Ja

Fe

-20000

ar y

0

-40000 -60000 -80000

Table 1: Relevant data of the RWHS at IUB Rainfall Catchme Demand Harvested Storage Deficiency Surplus (m) nt (m2) (L) Rainwater (L) (L) (L) (L) January 0.0078 2301 -59199 February 0.0217 6401.5 -55098.5 March 0.0648 19116 -42384 April 0.1442 42539 -18961 May 0.2962 87379 25879 June 0.347 102365 40865 295 61500 50000 July 0.3951 116554.5 55054.5 August 0.3003 88588.5 27088.5 September 0.3442 101539 40039 October 0.1846 54457 -7043 November 0.0337 9941.5 -1558.5 December 0.0098 2891 -8609 Month

It has been found that the demand for water can be fulfilled from May to September by harvested rainwater. In addition, approximately 1680 mm of Dhaka city’s annual average rainfall of 2150 mm has been found to precipitate over 5 months from May to September5. With the maximum amount of rainfall in July, the harvested rainwater reaches a maximum of 0.117 million L. However, deficiency has been found to persist for almost seven months from October to April due to moderate rainfall. During this period, the demand could be fulfilled with supplied water. In addition, the average surplus water from May to September has been estimated to be around 0.038 million L with minimum surplus of 40039 L in September.

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Rainwater harvesting in Bangladesh

For the recharge, the rooftop of gymnasium wing and another portion of rooftop of the academic building have been considered as catchment, with the total area of approximately 507.5 m2. Two boreholes have been constructed for the recharge. 48.78 m boring was done for each borehole to install PVC pipes with a diameter of 152 mm. The sandy soil has been found in the first 34.86 m depth. Strainers with a length of 9.15 m have also been placed in the boreholes. The size of the desilting and percolation pit has been 3.05m1.22m1.40m and 1.22m1.22m1.83m respectively. With the seepage rate of 900 L/hour/m2 per borehole, it has been estimated that around 0.013 million L of harvested water will be filtered and recharged per hour into the groundwater. In addition, two monitoring wells have been installed at a similar depth for periodical monitoring of quality and quantity of the harvested water.

Figure 3: A cross-section of the recharge pit

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Potentials, challenges and stakeholders’ responses Figure 4: Recharge pit and monitoring wells

The total cost for the RHS at IUB premises is BDT 4,16,168. It has been estimated that each year approximately BDT 5,202 as DWASA bill and BDT 24,000 as the cost of electricity consumption to extract water would be saved. Furthermore, approximately a minimum amount of BDT 5,000 would also be saved annually as the maintenance cost for runoff of rainfall. In total, a cost of BDT 34,202 would be saved per annum.

Considering these factors, the payback of the designed system would be achieved by around 12.16 years.

Concluding remarks The successful demonstration of RWHS at IUB signifies that rainwater harvesting is a profitable proposition for an institution like IUB. The system is reducing the cost of extracting and is contributing to conserving groundwater. It is also apparent that RWHS is beneficial for the overall water scenario of Dhaka city. This pilot project is the demonstration to gain the attraction of similar institutes to promote RWHS. This successful demonstration sets out the precedent to scale up such initiatives in Bangladesh to promote RWHS.

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Rainwater harvesting in Bangladesh References Biswas S K, Mahtab S B and Rahman M M (2010) Integrated Water Resources Management Options for Dhaka City, Proceedings of International Conference on Environmental Aspects of Bangladesh, pp.

179-181, Accessed on April 2012, Available: http://benjapan.org/iceab10/47.pdf BMD (2004) Bangladesh Meteorological Department Islam M M, Chou F N F and Kabir M R (2010) Feasibility and

acceptability study of rainwater use to the acute water shortage areas in Dhaka City, Bangladesh. J. of Nat Hazards, 56, pp. 93-111 The News Today (2011) Rainwater Harvesting to be Made Mandatory in Capital, Accessed on April 2012, Available: http://www.newstoday.com.bd/index.php?option=details&news_id=3513 6&date=2011-08-03 UN-HABITAT (2012) Beneficiaries & Capacity Builders: Rainwater Harvesting and Utilisation, United Nations Human Settlements Programme, Accessed on April 2012, Available:http://www.hpscste.gov.in/rwh/Blue_Drop_Series_02_Capacity_ Building.pdf WWF (2009) Mega-Stress for Mega-Cities: A Climate Vulnerability Ranking of Major Coastal Cities in Asia, World Wide Fund for Nature, Accessed on April 2012, Available: http://www.city-infos.com/list-ofmegacities-2011

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Part TWO Stakeholders' response

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Potentials, challenges and stakeholders’ responses

Role of WaterAid for promoting rainwater harvesting in Bangladesh Hasin JAHAN

Introduction In the WaterAid’s Global Country Strategy one of the main priority areas is to advocate for the essential role of safe water, improved hygiene and sanitation in human development. Under this global aim WaterAid Bangladesh set its strategic objective to influence government, donors and private sector for integrating WaSH in their development policy, priority and business plan. WaterAid is working since 1986 in Bangladesh to provide access to safe water, improved sanitation and hygiene in the poorer communities. In 2010 WaterAid Bangladesh prepared its Country Strategic Plan (CSP) for 2011-2016. During preparation of CSP, a study had been conducted on water and sanitation situation in Bangladesh. Water crisis in urban areas had emerged as an area of concern in that study. Rainwater harvesting had been identified one of the potential solutions to combat the water crisis. Therefore, promotion of urban rainwater harvesting had been considered as one of the priority advocacy agenda of WaterAid Bangladesh.

Contributing in the knowledge production process As a part of the advocacy agendum, WaterAid analysed the existing situation of rainwater harvesting in Bangladesh. This analysis identified lack of awareness among mass population, academicians, researchers,

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Rainwater harvesting in Bangladesh practitioners, and policy makers. It also identified lack of initiatives for technology transfer. This study explored that at present professionals have limited expertise and experience in constructing rainwater harvesting systems in urban context. Thereby, the design and cost estimation, operation, maintenance, and management modalities, etc for urban rainwater harvesting plants have not been clear to anyone. The concept of groundwater recharge, which is an integral part of rainwater harvesting, remained absent in the thinking process and practices. There is also legislative lacking which also acted as a silent factor for rainwater harvesting not being promoted widely.

To address these knowledge gaps, WaterAid went into a dialogue with Centre for Science and Environment (CSE), India for capacity building and technology transfer. CSE is a renowned institute which contributed significantly in the promotion of rainwater harvesting across India and in many other countries. Upon the successful collaboration with CSE, WaterAid Bangladesh initiated an exclusive training on urban rainwater harvesting. Having technical support from CSE, WaterAid Bangladesh launches a twice a year training programme for practitioners, academics, researchers, implementers, and policy makers. It was expected that these groups of trained personnel will expand their experiences in their related fields. Simultaneously, a voluntary platform – RAiN forum – had evolved from the participants of the first batch of the training programme to promote rainwater harvesting in Bangladesh.

Gaining this technical skills, WaterAid constructed a few demonstration plants for rainwater harvesting at a number of strategic locations in Dhaka such as Bangladesh University of Engineering and Technology (BUET), Public Works Department (PWD), Independent University of Bangladesh (IUB), Shahjalal University of Science and Technology (SUST) and an NGO premises- Village Education and Resource Center (VERC). It was expected that the students, academicians and researchers would use these plants for learning and research.

Disseminating the potentials of rainwater harvesting Simultaneously WaterAid Bangladesh organised three exclusive seminars with Institute of Engineers Bangladesh (IEB), Institute of Architects Bangladesh (IAB), and Bangladesh Institute of Planners (BIP) to create awareness among policy makers and practitioners. The objective of such event was to capitalise the role of professional fronts for disseminating and strengthening the potentials of rainwater harvesting in Bangladesh.

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Potentials, challenges and stakeholders’ responses To widen the awareness raising periphery and popularise rainwater harvesting, WaterAid started observing Rain Day in each year on the first day of Ashar (first month of the rainy season of Bangla calendar).

This is an open event which allows an inclusive participation of anyone to know and disseminate the potentials of rainwater harvesting in Bangladesh. Following these events, the first ever National Convention on Rainwater Harvesting, 2012 had been organised by WaterAid in collaboration with BUET, IWM and RAiN forum. More than 250 people from different parts of Bangladesh participated and quite a few international participants also presented their papers. This convention has been planned to be undertaken bi annually.

WaterAid believes in the promotion of rainwater harvesting through its extended supporters like the training fellows received training from WaterAid and CSE, members of RAiN forum and all the technical institutes signed agreements with WaterAid. WaterAid patrons RAiN forum in designing and maintaining a website www.rainforum.org for accessing rainwater related info. RAiN forum has started rolling out of orientation programme on urban rainwater harvesting for practitioners, academicians and researchers. It is also delivering awareness raising campaign targeting schools and offering technical support to industries as well.

Enhancing academic curriculum To institutionalise the knowledge production process and mainstreaming rainwater harvesting in the educational systems, WaterAid took initiatives to include this within the curriculum of different technical institutes. Academics who participated into the urban rainwater training courses jointly organised by WaterAid and CSE remained instrumental for this. Many of them started incorporating relevant contents of rainwater harvesting under different courses. WaterAid initiated several researches by students and academicians.

Furthermore, WaterAid signed strategic MoUs with renowned universities like North South University (NSU), Shahjalal University of Science and Technology (SUST), and University of Science, Information and Technology (USIT) for joint initiatives includes inclusion of rainwater harvesting in course curricula, initiating relevant researches and establishing knowledge hubs. A few more signing of MoUs are to be held soon. WaterAid is taking assistance from CSE to design curricula for technical institutes including relevant educational materials.

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Rainwater harvesting in Bangladesh

WaterAid is establishing rain centre/corner – a dedicated resource centre on rainwater harvesting at the mentioned institutes. These rain centres will allow wider audiences to access information related to rainwater harvesting.

Concluding remarks As per the strategic objective of WaterAid Bangladesh it continues its efforts towards policy influencing. WaterAid, jointly with RAiN forum, provided inputs for incorporating practical aspects of rainwater collection reuse and recharge into the designated chapter of the draft Bangladesh National Building Code (BNBC). Currently, BNBC is under approval process. In addition to this, WaterAid is also pursuing with RAJUK for issuing a circular to translate this into action. WaterAid believes that rainwater harvesting can be made popularised through a systematic way together with the stakeholders.

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Potentials, challenges and stakeholders’ responses

Engagement of ITN-BUET to promote rainwater harvesting Maharam DAKUA

Introduction ITN-BUET is a centre of Bangladesh University of Engineering and Technology (BUET) of knowledge and skill development in water supply and sanitation (WSS) sector. It strives for expansion of knowledge-base through networking to ensure human resources development for promoting sustainable development of WSS sector. The main focus of ITN centre is ‘capacity building’ within WSS sector. ITN have promoted an approach of skill transfer within social, technical and institutional areas. Conceptually, ITN renders its services on a multiplier effect. It develops curriculum; produces master trainers; develops teaching and training materials and develops Research & Development (R&D) skills in the sector relating to the socio-economic context of the country. ITN has a special niche for capacity building in the WSS sector. ITN has positioned itself in the WSS sector as a capacity building partner for sustainable development of Water Supply and Sanitation (WatSan). It has emerged as an institution that is playing a bridging role in between academic institutions and implementing organisations in WatSan sector.

ITN-BUET vision on water crisis and rainwater harvesting With a long-term vision to contribute to the management of water crisis in Bangladesh, exploring alternative water sources is the critical agenda of ITN-BUET. As the water scarcity in different parts of Bangladesh has

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Rainwater harvesting in Bangladesh become prominent in recent past, it has been deemed as a necessity for water professionals to look for the alternative sources of current practices considering the sustainability issue. ITN-BUET has been working in both urban and rural areas to solve the water crisis and in that process; rainwater harvesting has been identified one of the very few sources of potential alternatives in many areas. Bangladesh being a tropical country receives heavy rainfall during the rainy season, which refers geographical potential for rainwater harvesting. Quality of surface water, insufficient water in surface water bodies and limited groundwater is also considered as a driving force to look for alternatives like rainwater as a source of water in Bangladesh.

ITN-BUET and WaterAid collaboration To explore the potential of rainwater harvesting in urban areas of Bangladesh, ITN-BUET started application researches. In the process of doing those researches, ITN-BUET had an opportunity to work with WaterAid Bangladesh, an international NGO who are also working to mitigate the water and sanitation crisis in Bangladesh. WaterAid Bangladesh prioritises ‘promotion of urban rainwater harvesting’ as one of its critical agenda. As a part of this joint endeavour, ITN-BUET and WaterAid installed a demonstration plant of rainwater harvesting in BUET cafeteria premises in 2011. With the support of WaterAid, ITNBUET initiated to install RWHS (Rainwater Harvesting System) at BUET campus for reducing the water logging problem during monsoon.

Auditorium and cafeteria rooftop were considered as catchment for harvesting rainwater under a piloting scheme. Both the recharge and storage system were installed for a total of 892 m2 catchment area which includes the roof of cafeteria and auditorium.

Participation in training on rainwater harvesting WaterAid Bangladesh in collaboration with Centre for Science and Environment (CSE), a centre of excellence in India has been promoting the concept of rainwater harvesting, particularly in urban areas, as a technological solution that can be adopted by all. In their second training programme, WaterAid invited two researchers from ITN-BUET. Through this training programme, the policy, design and practices on rainwater harvesting were brought into light to promote the technology in urban areas of Bangladesh.

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ITN-BUET and RAiN forum collaboration to promote rainwater harvesting In the training programme on urban rainwater harvesting organised by WaterAid Bangladesh, ITN-BUET researchers came to know about RAiN forum which was formed by the trainees of the first batch of this training. This was followed by collaboration between ITN-BUET and RAiN forum to promote rainwater harvesting through workshops on rainwater harvesting.

RAiN forum in Bangladesh in collaboration with International Training Network Centre, BUET (ITN-BUET), organised two training programme on ‘Rainwater Harvesting: Exploring Rainwater as a Tool for Sustainable Water Management in Bangladesh' at ITN-BUET seminar room, Dhaka.

The training courses were designed for civil engineers, architects, urban planners, environmentalists, academics working in the government and non-government organisations, semi-government organisations, universities and private organisations who are interested to learn more about theory, practice (design), policies and legal aspects of rainwater harvesting in practical fields. Few positions were also allocated for students of reputed universities.

ITN-BUET researchers, as a part of RAiN forum facilitated two-day long workshops, one in December 2012 and second one in March 2013. In these two workshops, total of 68 professionals and students were trained on rainwater harvesting. Apart from that, ITN-BUET researchers also facilitated a day-long workshop for architects that was organised by Institute of Architects Bangladesh (IAB) in December 2012.

This collaboration contributed in the knowledge sharing process as well.

Using the platform of RAiN forum, ITN-BUET researchers took part in a process of research collaboration with University of Information and Technological Sciences (UITS) to implement a small rainwater harvesting system in a school of Gazaria, Munshiganj district and conducted research works with university students.

ITN-BUET research in coastal areas on storage of rainwater In order find out the suitability of stored rainwater for drinking purposes, ITN-BUET carried out a research under EC-CAFOD funded ‘Improved Food and Livelihood Security in Bagerhat District, Bangladesh in the Context of Increased Disaster Risk and Climate Change’ project.

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Rainwater harvesting in Bangladesh This project was designed to prove alternative ideas about the common perception on rainwater. It encountered the perception that rainwater deteriorates with time and is unsafe for using considered to be the major constraint for using this water in urban areas.

Though in many rural areas of Bangladesh rainwater is the main source of drinking water, people from urban community is often found negligent to use rainwater for the aforementioned perception. To test the quality of stored rainwater, ITN-BUET conducted a research under the project where quality of rainwater was monitored regularly over different time period and was found satisfactory.

ITN-BUET emphasised on proper maintenance of the system to store rainwater for a longer period giving special attention on applying preventive measures to reduce contamination of stored water. In addition, a solar water heater was installed with the system to reduce the risk of any microbial contamination that may occur at any point of the system. The results showed that microbial contamination was reduced by implementing proper maintenance and can be eliminated by disinfection system. The result of this project was encouraging to use rainwater in urban areas of Bangladesh.

ITN-BUET ongoing research on urban rainwater harvesting As the water supply sector in Dhaka is largely dependent on ground water source (87% of the city supply is covered by groundwater), over extraction of groundwater from aquifers, supplemented by the paved area which reduces the chance of infiltration of rainwater has been considered as a threat for sustainability of current water management system. As a result, lots of tube wells are getting abandoned every year for the depletion of ground water table. Therefore, interventions need to be undertaken to arrest the rate of ground water declination in areas like Dhaka.

The recharging of aquifers by rainwater harvesting through recharge wells could be a good solution where the rainwater will be channelled from the catchment area to the recharge wells and finally to the aquifer after filtration. To evaluate the success of recharge system, the trend of improvement of ground water table with time and the quality of aquifer need to be assessed. The hydro-geological analysis of the whole system will be needed to develop a guideline and overcome the constraints that could hinder the recharge system.

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Potentials, challenges and stakeholders’ responses Successful implementation and the results will help to develop the system which will definitely benefit the ongoing water crisis of Dhaka city and other water scarce areas. To explore the scope of implementing rainwater harvesting in dense urban cities like Dhaka and assess the impact on it on water cycle as well as water supply system, ITN-BUET undertook a research study on ‘Storage and Recharge Potential of Rainwater in Dhaka City to Promote Ideal Practice of Rainwater Harvesting System in Urban Areas’. The programme is supported by WaterAid. This research programme has started in October 2012 and will run till September 2015. The main objectives of this research are: •

Monitoring and testing of stored water quality in different seasons.

•

Monitoring of water quality in aquifer after groundwater recharge in different seasons.

•

Analysis of recharge trend into the aquifer through recharge well.

•

User’s perception survey to help accommodate the user friendly approach of rainwater harvesting.

•

Developing a generic guideline and recommendations for rainwater harvesting system.

Figure 1: Rainwater harvesting systems at BUET, IUB, PWD and VERC (clockwise) to be monitored under ITN-BUET-WaterAid research project

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Rainwater harvesting in Bangladesh The research programme will monitor and assess the impacts of rainwater harvesting system installed at BUET, Independent University Bangladesh (IUB), Public Works Department (PWD) and Village Education Resource Centre (VERC) premises. In the first six months of year one of this research, monitoring wells have been installed with the systems and water quality have been measured seasonally.

Concluding remarks Under the initiative of promoting rainwater harvesting in urban areas, ITN-BUET and WaterAid are willing to work jointly through research works and other strategic partnerships. ITN-BUET is a network of knowledge and skill development for water supply and sanitation (WSS) sector professionals in Bangladesh. ITN-BUET has its interest to collaborate with WaterAid and agreed to establish a formal strategic partnership to achieve the following objectives: •

Establish a knowledge corner (Rain corner/centre) within ITN-BUET centre for wider dissemination of rainwater harvesting related information at the university premises

•

Promote research on rainwater harvesting and dissemination to wider audiences

•

Support training and capacity building initiatives on rainwater harvesting

ITN-BUET, as a part of an academia has been working with a motive of bringing the research outcomes from practical fields into its institutional field since its beginning. As currently scarcity of safe water and sustainability of current practices in urban and peri-urban areas have become a concerning issue, it is a demand of high priority to explore options like rainwater harvesting and find the suitable ways to its installation, which is a major challenge in cities like Dhaka. Therefore, ITN-BUET, through its network, researches and resources, intend to overcome the challenges by developing guideline and preparing demonstration sites that will be convenient for the professionals to understand and make the system easy for the users to install to reduce the crisis of water in future.

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Potentials, challenges and stakeholders’ responses

Rainwater harvesting system and aquifer recharge project at MIST Abdullah FARUK & Mohammad ARIFUZZAMAN

Introduction Rainfall plays an important role in global and aquatic ecosystems along with surface and groundwater. Availability and quality of water determine ecosystem efficiency, both for agricultural and natural systems. Water resources, especially groundwater reserves in Bangladesh are now under pressure due to increasing demand for water for various reasons.

Rainwater harvesting for recharging aquifer can be one of the major solutions of this problem. In Bangladesh few initiatives have been undertaken regarding rainwater harvesting to mitigate water crisis management and to address aquifer level decreasing problem, especially in Dhaka.

In this context Civil Engineering Department of Military Institute of Science and Technology (MIST) with technical assistance from WaterAid Bangladesh (WAB) initiated a project ‘Construction of Rainwater Harvesting System and Aquifer Recharge System at Military Institute of Science and Technology (MIST), Mirpur Cantonment, Dhaka, Bangladesh’ to develop the process of aquifer recharge from harvested rainwater.

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Background of the project At present, water demand of Dhaka city is fulfilled by extraction of groundwater and three water treatment plants. These initiatives are not enough for meeting the increasing demand of water. Unfortunately, the government has no policy and explicit strategy for rainwater potential utilisation and substantial initiatives have not been taken yet to make it popular among the people.

Currently few organisations and NGOs are working on this issue in Bangladesh. In Dhaka city municipal water demand was only 150 million litres per day (mld) in 1963, According to DWASA it has increased rapidly in the last few decades, which was 1,500 mld in 1998 and 2,100 mld in 2005. Currently, Dhaka WASA can supply about 70 percent of the total water demand. The present water supply capacity of Dhaka WASA is 2,110 mld against the demand of 2,470 mld.

Water supply of Dhaka city is heavily dependent on groundwater extraction where more than 87 percent of the supplied water is being extracted from this source. DWASA extracts 1,680 million litres of water per day from underground and each year the rate of extraction through deep-water pumps is increasing at a frightening rate of 15 percent. Such extensive dependency enhances a very high depletion rate of groundwater table.

Dhaka city has been experiencing a sharp declination in groundwater table with more than 20 meters lower down during the last seven years at a rate of 2.81 meter per year (m/y) which was only 0.33 m/y in 1990.

It is observed that the potential groundwater recharge of Dhaka city is only 1.33 m/y in contrast to 2.81 m/y of groundwater depletion rate.

Such findings imply that despite a sufficient amount of rainfall, Dhaka city is experiencing 1.48 m/y groundwater recharge deficit every year.

Moreover, an increased rate of urbanisation, illegal occupation and encroachment of water bodies reduce the amount and volume of surface water around the city, deteriorating further the present situation.

In this context rainwater harvesting can be a sustainable solution considering the average rainfall in Bangladesh. The average annual rainfall varies from a maximum of 5,690 mm in the northeast of Bangladesh to minimum of 1,110 mm in the west.

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Potentials, challenges and stakeholders’ responses Figure 1: Average monthly rainfall in Bangladesh

Avg Rainfall

Avg. Rainfall (mm)

Avg. Rain Fall Days

400 350 300 250 200 150 100 50 0

Months Though there is a huge opportunity in rainwater there might be questions like: How to make use of rainwater popular among the mass people? Quality of water can be ensured or not? What potential can rainwater harvesting offer to solve global or local water crisis or to enable increased human well-being to protect our environment? What role can small-scale decentralised rainfall harvesting and storage play in integrated water resource management? How to make the system economical?

To find out the solution of above questions, Civil Engineering Department of Military Institute of Science and Technology (MIST) are continuing research on rainwater harvesting system. As part of it, a rainwater harvesting system and aquifer recharge pit construction, has been completed with assistance from WaterAid Bangladesh (WAB). The current project is among those initiatives to study feasibility of ‘Rainwater Harvesting and Aquifer Recharge System’ and introducing it as a demonstration which could be replicated in the entire Dhaka city and other areas. In addition, monitoring the quality of water and suitability of using for daily purpose was another priority of this project.

Description of the Project The project is located at Military Institute of Science and Technology (MIST), Mirpur Cantonment, Dhaka. The project was started at MIST as a pilot project. Construction of the project started on March 31, 2013 and

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Rainwater harvesting in Bangladesh was finished on April 12, 2013. Half of the roof of the student officers’ mess building has been taken as catchment for this project. Initially, part of rainwater will be utilised for washing purpose and the rest will be recharged in aquifer through recharge pit. Soil profile of the project site was tested to identify the project site. Upon identifying the suitable site the recharge pit was designed.

Figure 02: Soil profile of the site

Total costing for this project was around 135,000.00 BDT (hundred and thirty five thousands BDT only). The main components include (a) plumbing work costs 45,000.00 BDT (b) aquifer recharge system including monitoring well costs 40,000,00 BDT (c) masonry work for storage, filtration and recharge unit costs 50,000.00 BDT. The project was designed using the following considerations (table 01).

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Potentials, challenges and stakeholders’ responses Table 1: Detailed calculations of the project Components

Considerations and Calculations

a. Potential Rainfall in Catchment Area

Total catchment area = 178.22 m2 =178 m2 Annual average rainfall in Dhaka = 2000 mm = 2 m Total rainfall on the catchment = (178x2) m3 = 356 m3 Potential rainfall = (356 x 0.8) m3 =284.8 m3 =284,800 L

b. First Flushing Device

Using 100 mm diameter pipe Length of pipe = 11.05 x4 = 44.2 m Area = 3.1416x0.12/4 = 0.007854 m2 Volume of first flushing device = (44.2 x 0.007854) m3=.347 m3 Total catchment area =170 m2 Considering 2 mm rainfall for fast flashing, Estimated volume of rainfall for first flushing = 170x.002 m3=.34 m3

c. Storage Volume

Length of the storage tank = 2.5 m Height of the storage tank = 0.9 m Width of the storage tank = 1.1 m Volume of storage=2.42x1.1x0.9m3 = 2.3958m3 = 2396 L

d. Utilisation of Water

Let’s consider, daily water used in washing pit = 1,500 L Six months tentative water use for washing = 1,500x30x6 = 270,000 L Every day there will not be rainfall. Let’s consider 40 percent days we get rainfall and we can use rainwater in 40 percent days in the considered time.

Then water used for washing purpose comes = 270,000x0.4 = 108,000 L Water can be recharged through recharge pit = (272,000108,000) L = 164,000 L

e. Seepage Rate

Fine sand seepage rate = .2-.3 L/m2/s Let the seepage rate =.25 L/m2/s Bio-Sand filter size = 1mx1mx1m For 1m2 in 1 hour = 900 L Rainfall intensity = 100 mm/hr In Dhaka normal intense rainfall duration is 15 min 15 minutes rainfall = 25 mm = .025 m Total rainfall volume for 15 min = (179x.002) m3=0.358 m3=358 L Therefore, seepage will be done and possibility of overflow of recharge pit is negligible.

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Rainwater harvesting in Bangladesh

Achievement of the project The major achievement of this pilot project is harvested rainwater will be used readily for washing purpose of around 500 people’s clothes washing which will save good expense of water (minimum 1,500 L/day), power and money. Problem of water logging in this area will be reduced which will assist in vegetation. This project is a collaborative approach to combat the water crisis in Bangladesh. This project could be a benchmark for replicating successful rainwater harvesting system in major establishment like cantonment areas and academic institutions.

The technical issues will provide future technical knowledge for constructing similar plants. Moreover, this pilot project is an effort for demonstration which could be replicated in the entire Dhaka city and other areas.

Figure 3: Milestones of the project

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Boring of recharge pit

Recharge pit & monitoring well

Plumbing layout of the project

First flushing device

Potentials, challenges and stakeholders’ responses

Concluding remarks Rainwater harvesting and aquifer recharge system should be promoted and implemented in urban areas for a variety of reasons, especially in the dense cities like Dhaka. The increased use of rainwater harvesting provides additional water supply and reduce pressures of demand on surrounding surface and groundwater resources. Private, commercial and public house owners should be encouraged to invest in rainwater harvesting for household consumption. Rainwater harvesting plant could address water stagnancy occurred by run-off during monsoon.

Households can use rainwater instead of supply water for their regular domestic purposes which will decrease pressure on water supply, therefore power efficiency will increase.

Using rainwater, many countries have got success even with annual rainfall lower than that of Bangladesh. So, there is enough potentiality for exploiting this fresh water source by applying the simple technology of rainwater harvesting system and its various methods according to building design, geological and aquifer status and climatic factors of that specific region. But at first, the Government of Bangladesh has to take effective steps to make it popular among the citizens, which requires strong technical and logistics support with mandatory regulation. A collaborative action of various NGOs, developers and development authorities could promote rainwater harvesting in Bangladesh. This project sets the precedent of such action.

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Rainwater harvesting in Bangladesh

Promoting rainwater in the coastal areas of Bangladesh: a case study of a project of Nabolok Md Maynuddin SAKE

Introduction To address the scarcity of drinking water in the south-western region of Bangladesh different alternatives have been emerged traditionally. In terms of institutional responses several government and nongovernment organisations have developed different mechanisms. Among those rainwater has been assumed as a sustainable solution to address the salinity problem of drinking water in this region. Community people of Paikgacha Paurashava proved this assumption true with the support of Sustainable Environmental Health Initiatives (SEHI) project of Nabolok. In Abasan (a low-cost housing settlement) community there was no drinking water source. Community people used to collect drinking water from two miles away. But this water was highly contaminated by iron and saline. Pond water was the only alternative option for this community.

Upon the completion of SEHI project rainwater became the most reliable water source for them. Right now the community people are using rainwater for various purposes such as drinking, cooking, washing, cleaning and others domestic need. Apart from the rainy season the preserved rainwater is the major source for drinking and cooking. It has been observed that neighbouring communities are also collecting rainwater from the Abasan rainwater harvesting system (RWHS).

Therefore the SEHI project provided a sustainable solution for drinking

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Potentials, challenges and stakeholders’ responses water through the Abasan rainwater harvesting system (RWHS) in these communities.

Background of the project In March 2006 a support programme of Bangladesh Government implemented the Abasan Prokalpo for landless and houseless people in Paikgacha Pourashava of Khulna district. There are five barracks and ten houses in each barrack. Abasan community is situated in 5no ward of Paikgacha Pourashava of Khulna district. Its total household is 50 and total population is 208 where male is 111 and female is 97. Among them under 5 aged children are 16. The main occupation of this community people are day labour, van puller, mason, tailors, brick field worker, fisherman and shrimp firming related job.

The scarcity of safe and adequate drinking water was the major problem of this community. The only sweet water pond was the available water source for this community. Later, to meet the water demand government installed three pond sand filters (PSF) for Abasan Prokalpo community.

But after the natural disaster “Aila� the ponds were overflowed by saline water and all PSFs failed to supply drinkable water. The saline water was used for cleaning, washing and others purposes. But it was impossible to use this water for drinking and cooking. For this reason the people of Abasan were collecting water from some shallow tube-well of drinking and cooking. Those tube-well are so far from the community.

Every day it takes one and half hours for collecting drinking and cooking water. In this context Nabolok Sustainable Environmental Health Initiatives (SEHI) project funded by WaterAid Bangladesh, took an initiative to reduce the water scarcity for Abasan Community.

Technical information of the project In this community average HH size is 4.16 persons and everyday water demand is 15-20 litres for drinking. There reservoir capacity of the installed RWHS is 2700 litres and community people can harvest more than 10,000 litres rainwater in rainy season. Total cost for each RWHS installation is BDT 18,856 with a filter. Catchment area of each RWHS is 130 sft. The SEHI project introduces GI sheet gutter to sustain the plant longer and to ensure easy cleaning mechanisms. This project also used a gate valve to ensure easy flashing for community people especially for women. The top platform of the reservoir has been used as a communal place. Twice a year the water has been tested by SEHI project. Two different types of tests for rainwater harvesting system have been

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Rainwater harvesting in Bangladesh performed. First one is TTC and second is pH. Till now its result is acceptable for drinking. After rainy season this water is mainly used for drinking. Once the reservoir is filled the water can be used for five to six months for drinking. This project helped the community people to get access in to drinkable water source which saved the time for water collection purposes. Now, the community people are using this time for income generating activities such as working in shrimp farm, brick field, packing, tailoring, housekeeping, handicrafts making etc. The additional money is helping them by enhancing livelihood opportunity.

Transformation after introducing RWHS The water supply system of this community was very poor & inadequate. There was no source of safe drinking water. Most of the HHs collecting water from tube-wells but those tube wells was contaminated by high iron and salinity. The women of the community had to bring water from a long distance and sometimes they had to drink dirty water from nearby pond. For this reason, they were affected by various waterborne diseases. In the rainy season it was so difficult to collect water from two mile away for women.

Upon the completion of RWHS, Abasan Prokalpo is self-sufficient for safe drinking. Every barrack’s households have a rainwater reservoir. It became the most important part for their daily life. They are taking care of the reservoir in own initiative. They are now leading a more or less disease free life, so they can save more. In present situation they are having safe water. Rainwater harvesting system allows the community people to store rainwater which supplies the safe drinking water demand. This added advantage of RWHS is contributing in the livelihood opportunity of this community.

Concluding remarks Piloting the SEHI project, rainwater harvesting system has been recognised as the best water option for Paikgacha Pourashava where pond and tube-wells water both are contaminated by saline. It has been proved as an ideal technology for coastal area to reduce water crisis.

Under the Sustainable Environmental Health Initiatives (SEHI) project there are another five communities and four institutes where RWHS has been installed as a safe drinking water source. Moreover, this project has direct contribution in the livelihood opportunity for the marginalised communities and sets an example of sustainable solution to address water crisis in the coastal areas of Bangladesh.

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Potentials, challenges and stakeholders’ responses

Rainwater harvesting demonstration plants in Dhaka Hasin JAHAN & Kazi Rashed HYDER

Introduction Despite the fact that the Dhaka city receives annual average rainfall of 2150 mm, a severe water crisis has been observed in many parts of the city over the last couple of years. Yet this large amount of rainfall is unutilised and drained out through storm sewer. Very recently Dhaka WASA claimed that the supply deficiency of Dhaka city has been overcome by the water treatment plant in Syedabad. However, the current situation may not prevail for a long time coping with unplanned population growth in Dhaka city. Moreover, over extraction of groundwater is resulting declination of water table at a rate of 3 m per year which is aggravating the situation further.

Rainwater as an alternative Rainwater harvesting (RWH) could be considered as a potential solution for meeting the emerging water crisis in urban context. Rainwater harvesting is a process of capturing rainwater, storing it for future use or recharging the groundwater artificially. RWHS usually consists of two components—storage and artificial recharging. Harvested rainwater could be used for domestic purposes. Rainfall in Dhaka city often creates huge water congestion. So, harvesting of rainwater can also reduce surface runoff and thus reduces the water congestion commonly

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Rainwater harvesting in Bangladesh known as urban flooding. In addition recharge will improve the declining scenario of groundwater.

To promote urban rainwater harvesting, WaterAid facilitated technology transfer through demonstration plants of RWHSs constructed at Bangladesh University of Engineering and Technology (BUET), Public Works Department (PWD), Independent University Bangladesh (IUB) and Village Education Resource Centre (VERC).

Rainwater harvesting system at BUET Bangladesh University of Engineering and Technology (BUET) is the oldest and the most prestigious engineering academic institution in Bangladesh. A RWHS has been installed at the auditorium of BUET. The rooftop of auditorium and cafeteria rooftop have been used as the catchment for capturing rainwater and provision has made to store the water and use for flushing toilets at auditorium and cafeteria. Provisions have been installed to divert excess amount of water to the recharging system. A total of two recharge wells have been constructed for artificial recharging. Rainwater passes through de-silting and sand filtration chamber before entering into the recharge wells. Finally filtered water will be recharged at a depth of 45 ft or more. It is expected that about 0.85 million litres (per annum) of water will be recharged into the aquifer. It is estimated that about 1.43 million litres per annum rainwater will be harvested by this RWHS. A total of eight PVC tanks of 500L capacity each have been used for water storage.

Figure 1: Schematic diagram of RWHS at BUET

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Potentials, challenges and stakeholders’ responses

Rainwater harvesting system at PWD head office Public Works Department (PWD) is a government organisation involved in infrastructure development. A RWHS has been installed at its office premises to supply rainwater for toilet flushing and gardening. It is estimated that a portion of roof top of the main building may harvest about 1.1 million L of rainwater per year. The harvested rainwater will be used for the specified toilets. A total of eight PVC tanks of 2000L capacity each have been used for water storage.

Rainwater harvesting system at IUB premises Independent University, Bangladesh (IUB), a renowned private university have come forward to set up RWHS at the university’s premises to minimise groundwater extraction, IUB has introduced Rainwater Harvesting System (RWHS) in its main campus for supplying rainwater for toilet flushing. Excess amount of water will be diverted to the recharging system. In this academic institution water demand is so high because of a huge number of students. The common problem in this institution was draining of huge volume of rainwater, which often creates problem regarding water stagnancy. Considering this problem the University was looking for a sustainable solution. The installed RWHS technology tackled the water stagnation problem and reduced the use of ground water.

The system designed at IUB has both the storage and recharge facilities.

The total catchment area includes some portions of the rooftop of academic building and a portion of the rooftop of the gymnasium wing.

It has been estimated that approximately 1.208 million litres of rainwater will be potentially harvested per annum with an annual storage and recharge potential of approximately 0.444 million litres and 0.764 million litres respectively. 48.78m boring was done and two PVC pipes were installed with a diameter of 150mm. The sandy soil has been found in the first 34.86m depth. Strainers with a length of 9.15m were also placed. With the seepage rate of 900 L/hour/m2, it has been estimated that around 0.013 million litres of harvested water will be filtered and recharged per hour into the groundwater.

Rainwater harvesting system at VERC Village Education Resource Centre (VERC) is a national non-government organisation working for women and children. A RWHS has been installed at its head office premises for supplying water to the training centre and the head office. It is estimated that the roof top of the

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Rainwater harvesting in Bangladesh building may harvest about 0.61 million litres of rainwater per year. The harvested rainwater will be stored into the existing underground reservoir. A portion of harvested water will be filtered and recharged at a depth of 21.5m or more into the aquifer.

Figure 2: Schematic diagram of RWHS at VERC

Concluding remarks These projects were designed to demonstrate the potentials of RWHS. There are areas of improvement in terms of handling excessive rainfall and maintaining water quality. though water quality, monitoring of harvested rainwater used to be done periodically. ITN-BUET has started a research for a period of 3 years to assess quality of rainwater stored and being recharged, impacts of recharge in groundwater table and users’ acceptance and satisfaction.

Moreover, these demonstration plants signify the potential of RWHS, which might pave the way for institutionalising RWHS in large scale infrastructure development projects.

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Potentials, challenges and stakeholders’ responses

BRAC University initiatives on RWH AKM SIRAJUDDIN

Introduction It has been acknowledge in the earlier papers that the acceptance of rainwater harvesting will expand rapidly if this method is treated like other building services and if designed into the structure instead of being retrofitted. Studies and experiments ought to do not only to establish the portability of rainwater but also to design buildings installed with rainwater catchment facilities with optimum treatment facilities. In the present context, rainwater harvesting is being seriously considered as an alternative option for water supply in Bangladesh. Understanding this proposition WaterAid Bangladesh involved Architecture department of BRAC University to contribute in the process of knowledge production. BRAC University also responded considering that there is a fourfold scope of works for architecture department regarding rainwater harvesting. These are: (a) as professional architect integrating RWH in building design, (b) as academician developing curriculum on RWH, (c) working with student bodies/ forums for awareness building and campaigning for RWH and finally (d) as an active pressure group, for advocating RWH in current and future building/complex projects. Department of architecture in BRAC University is involved in all these fourfold way of actions regarding RWH.

Professional attributes of BRAC University initiatives The research based professional consulting unit “design cell� of BRAC University is looking for integrating RWH in its entire architectural project.

Consequently in the BRAC staff-housing project (144 units) RWHS has been accommodated, which developed the professional skills of architects to introduce RWHS in a larger scale design project. This project was designed with an expectation that, this project will be implemented and a large community scaled RWH can be demonstrated. This initiative provided a benchmark knowledge production for architect professional in Bangladesh to introduce RWHS in the architectural design of buildings.

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Rainwater harvesting in Bangladesh

Academic attributes of BRAC University initiatives In terms of academic responses, Architecture department of BRAC University introduced 2 credit theory course ‘ARC 452: Design for the Environment’ in its undergraduate course curriculum. In this course RWH harvesting is incorporated with a view, that water as the most essential element of environment to be addressed while designing the building or settlement.

Under this course extensive lecture sessions have been designed for developing a better theoretical understanding of RWHS to introduce it in building design. This class room lecture sessions have been followed by a filed visit for watching the real-time projects in BUET, VERC and IUB. Students have to submit assignment after completing the field study. With an expectation of sensitising the young minds for ‘water’ this course will generate many young professional skilled with the technical knowhow to introduce RWHS in building design. Thus the academic attributes could help to create a very ‘water sensitive’ ‘architecture’ and ‘city’ in Bangladesh.

Awareness building attributes of BRAC University initiatives There are several student bodies in BRAC University. Through these, specifically ‘the earth and environment forum’ is actively being guided by the advisors from department of architecture for arranging and celebrating the ‘water day’ and many other seminars on RWHS for all the students, faculty members and staff of BRAC University. Through these events RWH becomes familiar to members of all strata in BRAC University. As a pressure group, concerned faculties and students are advocating for RWHS for the ongoing project of ‘permanent university campus’ at Aftabnagar, Dhaka.

This university campus size is around 1,000,000 sft. Building complex will be established in a five acre of land. Considering the huge amount of water to be consumed in this complex, RWHS would be a very sustainable solution. Advocating for this, would appear as very worthy one.

Concluding remarks As mentioned earlier in this paper that as an academic institution introducing RWHS could enhance the technical skills of the professional, curriculum could be developed and awareness building activities could be performed. Integrating these three attributes, the recent initiatives of BRAC University can ensure academic enhancement in the field of RWHS. These initiatives will develop the conceptual and theoretical understanding of RWHS by transferring the knowledge to a professional group. Therefore BRAC University initiatives could contribute to promote RWHS in an academic-professional continuum.

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Potentials, challenges and stakeholders’ responses

Promoting rainwater harvesting in industry and urban area: initiatives of RAiN forum Md Ashraful ALUM

Introduction The world's population has been constantly increasing and so has the water demand. However, global freshwater supplies are limited to a finite 2% of the total available water. The world’s urban population is currently growing at 4 times the rate of the rural population. With the inevitable escalating water demands, there is the need to optimise all systems that are related to the supply and demand of water. Rainwater harvesting is an alternative source of water supply system. In this context, study on rainwater harvesting techniques and management is needed to document the provisions of rainwater supply in the industrial and residential buildings. This paper is an attempt to explore how RWHS can be promoted in industry and urban area through the initiatives of professional and RAiN forum.

RAiN forum society in Bangladesh Availability of safe drinking water is one of the basic requirements for healthy living. Despite the advancement of technology in recent pasts, the global scenario still remains grim, as not all the inhabitants of the world have access to safe drinking water. With the appearance of increasing scarcity of fresh water resources, it is becoming a cause of concern for everyone to think about possible solutions to cope with the

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Rainwater harvesting in Bangladesh looming crisis. RAiN forum Society in Bangladesh have been formed to build a water literate society in Bangladesh and have been striving to develop a network among the professionals and the stakeholders to help developing sustainable practices in water management sector.

RAiN forum is a non-profit voluntary platform for knowledge sharing and promotion of rainwater among scientist, engineers, architects, planners, academicians, practitioners, administrators, students and others who are directly or indirectly concerned in sustainable practices of water management.

Vision of RAiN forum The vision of RAiN forum is dissemination, implementation and enactment of sustainable water management practices countrywide to resolve the crisis of water and improve water management system in a scientific manner with the theme of sustainable, green and safe earth for living.

Mission of RAiN forum To ensure sustainable water and storm water management by bringing changes in attitude and practice among the users for a better future by networking and dissemination of appropriate technology to the conscious society through training, workshop, seminar, project , awareness campaigning and media.

Role of the RAiN forum society

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Capacity building of professionals, architects, planners, engineers, researchers, academicians, law-makers, journalists, students and concerned persons through training programme on rainwater harvesting.

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Enhance social responsibility of citizen and help them think about future water scarcity and need for water conservation by awareness campaigning.

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Explore existing rainwater harvesting practices in and outside the country to know the current state of the art.

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Research and develop further scopes & techniques of rainwater harvesting.

Potentials, challenges and stakeholders’ responses •

Promote the application of rainwater for domestic purposes through information and knowledge dissemination.

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Work in joint collaboration with Universities, Government Organisations, Non-Government Organisations and International Agencies for implementing projects on Rainwater Harvesting.

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Assist in organising conferences, seminars, meetings, discussions, debates, study courses, collection of statistics, exhibitions, shows and tours to aware on natural water resource conservation.

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Provide consultancy in Rainwater Management and Rainwater Harvesting Technology for implementation.

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Assist Universities, colleges, schools, Government and NonGovernment offices, industries and important places to install Rainwater Harvesting System.

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Conduct research programme with the support of Ministries, concerned Departments and International Bodies.

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Publish books, magazines and advertising of Rainwater Harvesting through media.

Role of RAiN forum to promote rainwater harvesting in industries Right now industries in Bangladesh are dependent on different sources for water supply. Some buy bottled water for drinking purpose and if soft water is required as part of the process requirement; water softeners or reverse osmosis systems are opted for. It therefore makes eminent sense for industries to harvest rainwater because it saves money, it replenishes the groundwater and it brings to productive use soft rainwater.

Rapid growth of urbanisation also increases the pace of industrialisation and as a result large numbers of industries have been grown since the last two decades. In Bangladesh a good number of large, medium and small-sized industries in both public and private sectors based on both indigenous and imported raw materials have been established. Among them are jute, cotton, textile, fertilizer, engineering, shipbuilding, steel, oil-refinery, paper, newsprint, sugar, chemicals, cement and leather. All these industries play an important role in the national economy. It is inevitable that huge amount of water is required everyday among these industries. If rainwater harvesting system is used in these industries

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Rainwater harvesting in Bangladesh then significant amount of pressure would be reduced from city water supply system. In this context a presentation was given by RAiN forum to DBL group of industries to show the potential of rainwater harvesting of that industry.

A presentation was given to Northern Tausrafi industry where available catchment area for rainwater harvesting is 4371 sq. meter. Potential of rainwater harvesting is 65,56,500 litres water which is equivalent to 10,92,750 nos toilet flush that means 9 months toilet flushing for 2000 persons.The design process with the engineering team of the garments for maximum utilisation of RW harvesting has been initially done. The authority would go for implementation by this year. RWHS in Northern Tausrafi Garments building would be a significant example for other industries in Tongi industrial area.

Figure 1: Components of RWH in Northern Tausrafi industry

Catchment area

Pipe connection

Storage space

NAZ Group is one of the large composite ready garments industries in Gazipur area. It is a composite factory where 6000 workers produce products in 9,00,000 square feet area. After several motivational session with the authority, NAZ group is willing to install RWHS in their large building where catchment area is 1,36,000 SqFt. The design of the RWHS is done by the architectural team of IDYLLIC DESIGN which is also the member of RAiN forum. Harvested rainwater will be used in toilet flushing, floor cleaning, machine cleaning, vehicles washing, fire protection system and gardening. The construction of the system will be completed by the year of 2013.

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Potentials, challenges and stakeholders’ responses Figure 2: Proposed water fountain in NAZ garments

Figure 3: Proposed rainwater retention pond for emergency use in NAZ garments

Federated efforts of RAiN forum Under a collaborative approach RAiN forum has implemented several training programmes, workshops and other dissemination activities to promote RWHS in Bangladesh. In a training programme jointly organised

by WaterAid Bangladesh and Centre for Science of Environment (CSE), India, RAiN forum presented the Crisis of Water as well as potential of

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Rainwater harvesting in Bangladesh rainwater in Bangladesh. Apart from this training, RAiN forum, jointly with IAB (Institute of Architects Bangladesh), organised a one day workshop on rainwater harvesting at Wings Centre, Dhaka on December 15, 2012. 56 professional architects from all over the country got trained in this day-long workshop.

It was one of the major targets of RAiN forum to share knowledge on ideal practices of using limited water resources in Bangladesh to students and faculties. This will increase the awareness level among the new generation and hence, will help bringing the right attitude towards resource management. To discuss the current water crisis in urban and rural areas in Bangladesh, a workshop was organised by BRAC University Earth and Environment Forum (BUEEF) on 27 Nov 2012.

To sensitise people about the scarcity of safe water and the importance of using the resources properly, it is important to disseminate the knowledge and train up people who are directly concerned and also bear the responsibility of providing support by contributing as stakeholders. RAiN forum, jointly with ITN-BUET, organised a two day training programme on rainwater harvesting at ITN-BUET. The training programme was held on 22-23 December, 2012; where 32 participants including architects, engineers, planners, faculty members of reputed universities, NGO professionals, consultants and students from different parts of the country got trained on rainwater harvesting. RAiN forum jointly with ITN-BUET organised second training programme on Rainwater Harvesting at ITN-BUET. The training programme was held on 30-31 March, 2013 and participant was 34.

To facilitate one small step towards a more sustainable future for Bangladesh, a rainwater harvesting system was installed at Baluakandi Dr. Abdul Gaffar High School and College in Munshiganj. The system is designed to serve 1200 students and staffs of the school during rainy season. The programme was supported by San Francisco Art Institute, USA. Integration of enhanced knowledge of water, environment, sanitation, energy and sustainability was the prime objective. Main focus of this initiative is:

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Promote the concept of RWH and water conservation and application in schools.

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Create awareness about proper storage, handling and consumption of safe drinking water.

Potentials, challenges and stakeholders’ responses •

Create consciousness about personal hygiene, sanitation and its practices among school children.

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Workshop on necessity of rainwater harvesting for all the students and teachers was a part of the whole programme.

Concluding remarks In upcoming days RAiN forum will organise two day training programme on Alternative water options in Bangladesh at Khulna on 18-19 May, 2013. It will celebrate rain Day 2013 in collaboration with WaterAid on 15June, 2013. RAiN forum will continue promotional activities and mass awareness regarding RWHS in universities, industries, building developers and policy makers.

In terms of knowledge production research project opportunities will be explored jointly with other organisation such as DoE, WaterAid, CEGIS, ITN-BUET, WASA, Practical Action Bangladesh and NGO Forum. It is evident that promotion of new development initiatives has been institutionalised through networking. RAiN forum society of Bangladesh is performing such role to institutionalise RWHS in Bangladesh.

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