Report of the Committee on Surface Water Development and...

pp ladesh

July 2003

Government of the People’s Republic of Bangladesh

Ministry of Local Government,Rural Development & Co-operatives,Local Government Division

Reportofthe CommitteeonSurface Water Developmentand Managementfor Drinking Water Supplyinthe Arsenic affected areasofBangladesh

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July 2003

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Report of the Committee on Surface water Development and Management for Drinking water Supply in the Arsenic affected areas of Bangladesh

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Foreword

In the 5th meeting of the Secretaries Committee on Arsenic held on 14th August 2002, itwas decided that a plan for “Surface water development and management” for thepurpose of water supply in the arsenic affected areas in the country may be prepared byrelevant members of “National Committee of Experts on Arsenic”. Accordingly acommittee was formed vide memo no LGD/WS-3/Arsenic/Committee-4/2002/222dated 12-09-2002 (Appendix-a) by the Ministry of Local Government Rural developmentand Cooperatives with the following members:

i) Director General, WARPO Convenerv) Mr. S. K. M. Abdullah, Former DG, GSB Membervi) Professor Ainun Nishat, IUCN Memberii) Director General, Directorate of Environment Memberiii) Director General, BWDB Memberiv) Chief Engineer, DPHE Membervii) Representative of convener of National Arsenic Expert Committee Member-Secretary

Committee meetings were held on 23rd October 2002, 18th January 2003, 9th April 2003and 7th June 2003 respectively. Dr. Mustafa Kamal Farooque, Joint Director asrepresentative of DG, Directorate of Environment, Kazi Golam Mustofa, AdditionalChief Engineer as representative of DG, BWDB and Moniruzzaman, ExecutiveEngineer as representative of Chief Engineer, DPHE attended the meetings. MrIhtishamul Huq, Executive Engineer of DPHE was appointed member-secretary vidememo no LGD/WS-3/Arsenic/Committee-4/2002/281 dated 18-12-2002 (Appendix-b). The committee co-opted Mr. Saiful Alam, Senior Scientific Officer of WARPO asmember in the committee and invited Dr. Tanveer Ahsan, Urban specialist, WSP, WorldBank to attend the meeting as an expert observer vide memo no WARPO/A-28/2002/252781 dated 23-01-2003 (Appendix-c).


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CONTENTS

Executive Summary ................................................................................................ vi

1.0 Introduction.............................................................................................. 1

1.1 Background for Surface Water as Source of Drinking Water Supply ...... 11.2 Objective and the Terms of Reference ..............................................................1

2.0 Availability of Surface Water Resources................................................... 2

2.1 Rainfall ........................................................................................................................22.2 Stream flows...............................................................................................................3

Transboundary Flow Reduction ..........................................................................................32.3 Ponds and Surface Storages ..................................................................................72.4 Standing Water Bodies ...........................................................................................7

Residual Flood Water ............................................................................................................7Beel, Haor and Baor ..............................................................................................................7

3.0 Surface Water Quality............................................................................... 8

3.1 Industrial Pollution ..................................................................................................83.2 Poor Sanitation..........................................................................................................83.3 Transboundary Surface Water Quality...............................................................8

4.0 Current Status and Trends of Surface Water Use .................................... 9

5.0 Surface Water Management for Safe Water Supply ................................10

5.1 Urban Water Supply: Options.............................................................................17Rainwater Harvesting...........................................................................................................17Piped Distribution System from Surface Water Source .................................................17Water Supply in the Major Cities of Arsenic Affected Area..........................................18Domestic Filtration or Treatment .....................................................................................18

5.2 Rural Water Supply: Options ..............................................................................18Dug well.................................................................................................................................18Pond Sand Filter...................................................................................................................19Rainwater harvesting............................................................................................................20Rural Bulk Water Supply and Distribution.......................................................................21

6.0 Principles and Guidelines of Surface Water options for drinking watersupply ..................................................................................................... 23

6.1 Policy Principles to be adopted:.........................................................................236.2 Guidelines of Framework Plan for using Surface Water as Drinking

Water Sources ..........................................................................................................24

7.0 Recommendation ................................................................................... 26

REFERENCES...................................................................................................... 28


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TABLES

Table 1: Average Rainfall by Region (mm/month)………......…………….…………… 3Table 2: Summary of Available Surface Water Flows…………………………….…..…………7Table 3: Sources of Drinking Water Supply………...…………..…………………..… 10

FIGURES

Figure 1: Map of Hydrological Regions………………………………………..…….….4Figure 2: Average Annual Rainfall Isohyets……………………..….…...............................5Figure 3: Bangladesh Common/Border River………………………….………….….. ..6Figure 4: Percent Tubewell having Arsenic Content > 0.05mg/l…....……..……….…. .12Figure 5: Areas affected by lowering of Seasonal Water Table below 7m Suction

Limit (1995-1997)……………….……………………………………………13Figure 6: Village Hand Pump Types Needed at Full Irrigation Development.........……. 14Figure 7: Incidence of Iron in Groundwater………………………………………...….15Figure 8: Arsenic Concentration in Wells deeper than 200m……………..………….…16Figure 9: Completed Projects of Bangladesh Water Development Board..……………..17.


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Executive Summary

From time immemorial surface water sources e.g. dug wells, ponds, canals and rivers arebeing used for domestic purposes in the countryside. In 1972 Bangladesh started aprogram to provide safe and low cost drinking water to rural population through handtubewells. As a result by 1997 the program covered nearly about 97% of the ruralpopulation with tubewell water supply through both public and private initiatives. Withthe emergence of arsenic in the shallow aquifer, deeper aquifer with presently low arsenicconcentration was focused as a major strategic source for safe drinking water supply.Although shifting to surface water sources was discussed and often recognized by manyas alternate to groundwater sources, surface water options has not gained muchpopularity for a variety of reasons.

It is the Government policy to “Facilitate availability of safe and affordable drinking watersupplies through various means including rainwater harvesting and conservation” for all inhabitants,especially the poor. The commitment stated in the National Water Policy has also beenendorsed by the National Policy for Safe Water Supply and Sanitation. Governmentpolicy also attaches special importance to the conjunctive use of ground and surfacewater for variety of its uses.In Bangladesh there is overabundance of surface water in the monsoon season but itbecomes a scarce resource in the dry season as users (both inside and outside thecountry) compete to satisfy variety of their demands with these resource. Volume of riverflows available during seven-month period of the dry season (November- May) is around10-20 percent of the average annual transboundary inflows. However its distribution inspace and time is a constraint to the development of surface water based dependablewater supply system without interventions. Apart from the surface water inflows throughborder rivers, on an average we have 2360 mm of rainfall annually distributed unevenlyover time and space. More than eighty percent of this rainfall is available during the fivemonths (june-october) of the year and western part of the country receives less rainfallthan other part of the country. There are individual water bodies (e.g. beels, haors etc)that can be used for water supply. These perennial surface water sources includingindividual water bodies can be utilized with some treatment for piped distribution systemboth in the urban and rural areas.Ground water in general is used for domestic, industrial and irrigation purposes. In ruralareas low mineral content surface water is always preferred for cooking, bathing andwashing clothes etc. Tube well water is almost never used for bathing, washing clothes orcooking in the arsenic affected areas. Therefore options needs to be proposed inresponse to these cultural preferences in providing water in all-seasons and to meetdifferent categories of usages in the arsenic affected areas.The bulk water supply and distribution from surface water sources in the rural areas andtowns where local sources are inadequate for use is a medium to longer-term possibility.Perennial rivers, mostly the major rivers and their distributaries would be the surfacewater sources. If main river barrages are built, the network of possible distributarieswould be considerably increased. Perennial rivers could serve many villages, but thecapital cost and also cost of supply would be high. Capital cost would be less where wateris being conveyed for irrigation through open canals. It will however be possible torecover the cost of conveyance through weekly/monthly payments under anarrangement demonstrated by Barind Multipurpose Development Authority (BMDA) inthe Barind Tracts. The entire Southeast and a large part of the Southwest and South-central region may be served by this approach.


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It is likely that a major shift to bulk supplies from local sources to more distant surfacewater sources will be required in many cities and towns including Khulna in the nearfuture. Khulna could benefit from increased flows diverted from the Ganges, but may inthe meantime abstract fresh water from further upstream. Abstraction from a distantplaces like from river Jamuna or Padma for Dhaka City may be considered.Augmentation of dry season flows in the distributaris of Ganges and Meghna would berequired for Southwest and Southeast region. River water around most of the Majorcities is subject to the risk of pollution with consequent difficulties of using it withoutexpensive treatment. River water in any case will require primary treatment particularlythe sediment removal and final treatment before it is used for drinking.Dug well is the oldest method of drinking water supply in rural Bangladesh. The supplysource is the surface water stored in the upper layer underneath ground surface thatrenews annually through flood and rainfall. The technology has been successfully revivedwith some modification in many parts of the arsenic affected areas.Traditionally rural water supply to a large extent was based on protected ponds. Due tocontinuous dependency on the use of tubewell, people have been reluctant to use ponds,as biological quality of pond water is poor for variety of reasons. Now-a day ponds arebeing used for fish culture and the water have become unsuitable for drinking. Slow-sandFilters, a package type filter unit popularly known as Pond Sand Filter (PSF) have beendeveloped to treat pond water for domestic consumption and has been found suitable byBangladesh Arsenic Mitigation Water Supply Project (BAMWSP) in many parts of thearsenic affected areas.Rainwater harvesting during the monsoon has a potential to supplement the demandfor drinking water supply in all the arsenic affected areas. The option of rainwaterharvesting in the urban areas could be a bit expensive, and acceptance may require sometime. It is most likely an appropriate option in coastal areas where both the surface waterand groundwater are saline.The report concludes with the policy principles and guideline (Chapter-5) in preparingmitigation plan for adaptation and recommends the following towards enhancing theshare of surface water sources in the drinking water supply system in the near future inBangladesh:i) Improved Dug well has been proved a suitable surface water supply option in

many areas where water table remains within suction limit, well do not encounterpeat soil layer and yield from the well is sufficient for drinking purposes duringdriest part of the year. Improved Dug well as sources with community basedpiped distribution system as demonstrated by Dhaka Community Hospital inIshurdi, Pabna may be replicated under similar geological conditions followingthe guidelines approved by the National Committee of Experts on Arsenic;

ii) Reversion to pond use for drinking water supplies is a feasible option in areaswhere other pure drinking water sources are not available, land is procurable,equipped with reliable filters that could be maintained properly and there issufficient rainwater or other surface water sources refilling the ponds. Such anexample of Pond Sand Filter (PSF) in Patherghata of Barguna can be replicatedin other places following the approved guidelines. Existing Khash pond in aunion may be procured on lease for longer term. Private ponds may also beutilized on rent basis for the community water supply. These ponds must not beused for fish culture or for bathing, washing except for drinking purposes.Supervision by the Union Parishad Chairmen, Members is likely to generate goodO&M practices with this option. Ponds may be refilled by using irrigation canals;


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iii) Rainwater harvesting is likely to provide potable water supply round the year toindividual family in a village if sufficient storage facilities are available and storedwater is used wisely. Government may involve in promotional activity topopularize this option in general and subsidize the technology where it isabsolutely necessary;

iv) Other surface water sources: Network of irrigation canals of different irrigationprojects may serve town, growth centers and villages with piped distributionsystem. Surface water irrigation projects like Meghna-Donogoda IrrigationProject, Pabna Irrigation and Rural Development Project, Chandpur IrrigationProject, G. K Project etc cover a large area affected by groundwater arsenic.Development of irrigation network with perennial surface water sources in themedium term would be very much in line with the development of Major Riverwater resources through Barrage and pumps for multi purpose uses in themedium to longer term. A pilot project may be under taken in this regard;

v) Nearly half of the population still uses surface water sources for purposes otherthan drinking. Surface water is preferred for cooking, bathing and washingclothes. Therefore options selection may be based in response to these culturalpreferences in designing water supply system suitable for all season in the arsenicaffected areas;

vi) The poor especially the women suffer disproportionately when water supplyservices are poor. Surface water supply for drinking and domestic uses shouldgradually be transformed to piped distribution system for quality services;

vii) Poor sanitation poses a serious threat to surface water quality in Bangladesh.Conservation of fresh water sources from domestic pollution through raisingpublic awareness for improved sanitation should be considered essential for thedevelopment of surface water based drinking water supply;

viii) Industrial effluents, the major source of river pollution is required to be broughtunder control. Government should undertake cleanup program for the pollutedrivers and other water bodies. Polluters may be required under law to pay for thecleanup of polluted water bodies. Augmentation of fresh water flows in thepolluted rivers may be required to rejuvenate the quality of river water for watersupply purposes. Study may be sponsored to examine if augmentation of freshwater to Buriganga and other rivers around Dhaka can improve the water qualityof the river Buriganga as envisaged in draft National Water Management Plan(dNWMP), 2001;

ix) Legal and regulatory framework may be developed to help the process ofconservation of water bodies and its management and improve the investmentclimate for the private sector in surface water development and management;

x) In most cases surface water requires treatment before it can be used for drinkingpurposes. Research may be conducted to improve the existing technologiesincluding the improvement of small-scale water treatment plant and make themaffordable to the poor. Water quality monitoring of surface water sources in asystematic and regular basis is a prerequisite for the development of surface waterbased water supply system;

xi) The surface water resources available for water supply are widely distributed intime and space in the arsenic affected areas. A systematic approach is required fora water supply planning integrated with overall water resources development andmanagement plan;


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1.0 Introduction

There has been a considerable effort since 1990 to understand the issues/problemsrelated to arsenic and intervene in probable areas in order to mitigate the problems ofarsenic in Bangladesh. A National workshop was held on 3rd November 2001 atRajendapur, Gazipur and an international workshop was also held during 14-16 January2002, which gave possible direction to work out arsenic mitigation plan. A protocol fordrilling deep hand tubewell was prepared to guide drilling of wells in the non-coastal arsenicaffected areas. The document was approved in the 5th meeting of the “SecretariesCommittee on Arsenic”. In that meeting it was decided that a plan for “Surface waterdevelopment and management” for the purpose of water supply in the arsenic affectedareas in the country may be prepared by relevant members of “National Committee ofExperts on Arsenic”.

1.1 Background for Surface Water as Source of Drinking Water Supply

Bangladesh started an extensive program to provide safe drinking water at low cost torural population through hand tube well (HTWs) in the year 1972. By the year 1997Bangladesh achieved a remarkable success by providing 97% of the rural population withtube well water supply. Today there are 6-7million hand tube wells in the country. Lowcost, availability of groundwater in the upper aquifer and appropriateness at householdlevel with minimal maintenance made the technology popular especially among the poor.After the emergence of arsenic in the upper aquifer, lower/deeper aquifer has beenfocused as a major strategic source to meet the urgent need of safe drinking water supply.However there is still a gap of understanding about the horizontal and vertical extent ofcontamination, the prediction if arsenic contamination will change over time especially whendeeper aquifer is explored, sustainable yield of the deeper aquifer and finally the cost effectivesolution of immediate mitigation and the long-term solution.

From time immemorial surface water sources e.g. dug wells, ponds and rivers are beingused for domestic purposes in the countryside. Shifting to surface water sources at thispoint of time has been recognized by many. However the surface water options have notgained much popularity for variety of reasons.

1.2 Objective and the Terms of Reference

The objective of the report is to provide an insight and guide the concerned planners forincreased use of surface water as drinking water supply in the arsenic affected areas ofBangladesh. Terms of reference of the committee contain the followings;

1) Find out the availability of surface water resources;2) Find out the surface water options for drinking water supply;3) Prepare principles of development of surface water for drinking water supply4) Prepare guidelines of framework plan for using surface water as drinking water

source;5) Recommendations


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2.0 Availability of Surface Water Resources

In Bangladesh there is enough surface water in the monsoon season but it becomes ascarce resource in the dry season as users (both inside and outside the country) competeto satisfy variety of their demands with these resource. Volume of river flows availableduring seven-month period of the dry season (November- May) is around 10-20 percentof the annual average transboundary inflows. On an average 2.4m of rainfall occursannually in Bangladesh. Distribution of surface water flows in space and time is aconstraint to the development of surface water based dependable water supply system.Total water area excluding the rivers (beels, baors and ponds) still flooded in the monthof February, as observed on February 1997 imagery, including the maximum area ofKaptai Lake is around 7,584 km2. The ponds, tanks and ditches in the uncultivated areaare around 3,488 km2. There are about 1,288,222 ponds in Bangladesh, i.e. 21.4 pondsper mouza (BBS, 1997). For the purpose of national water resources planning, WaterResources Planning Organization (WARPO) has delineated the entire Bangladesh ineight hydrological regions (Figure-1), which is useful to describe the country in terms ofhow surface water hydrology interact with land and nature. The sources that could beavailable to meet drinking water needs in the arsenic affected areas and considered assurface water sources are briefly discussed below in reference to these hydrologicalregions;

i) Rainfall;ii) River flows during the dry season;iii) Surface water bodies like beels, lake, ponds etc;iv) Groundwater within the suction level of shallow tube wells.

2.1 Rainfall

More than eighty percent of the total rainfall is available during 5-month period ofmonsoon including the month of May (Table-1). As can be seen from the rainfall isohyte(Figure-2), Northeastern region has the most abundant while Southwest and Northwestregion have less rainfall availability. Average rainfall in the Southwest region is about1.6m annually. Rainwater harvesting during the monsoon has a potential to supplementthe demand for drinking water supply in all the arsenic affected areas. The rainfall in theremaining six month can not effectively be used for drinking purposes, as majority is lostthrough non-beneficial evaporation. A part of it is however used to supplement therecharge of upper groundwater storages considered as surface water source used by thedug wells. Therefore two-season approach (April-Oct and Nov-May) may be used forrainwater harvesting in designing catchment, storage volume for drinking purposes.

Table 1: Average Rainfall (R) by Region (mm/month)Region J F M A M J J A S O N D TotalSE 6 24 60 157 291 465 521 445 305 172 39 11 2271NW 8 11 22 72 214 347 437 319 312 124 12 7 1739NC 6 21 40 127 283 380 411 318 290 152 23 11 1956RE 6 20 48 130 262 468 561 443 329 171 38 11 2318SW 9 23 36 80 176 331 371 340 285 141 31 11 1665NE 9 31 82 255 475 661 664 527 457 202 32 13 3194SC 7 23 46 115 231 495 531 470 341 179 53 11 2307EH 5 17 44 124 251 610 688 488 270 186 59 11 2445B'desh 7 20 44 125 265 457 510 405 322 161 33 10 2360

Source: NWRD, dNWMPP


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2.2 Stream flows

Surface water flows available during dry season is the largest component of waterresources available in Bangladesh and major sources of these flows are cross-border rivershown in the Figure-3. Major Surface water inflows during dry season (Nov-May)through the major rivers is around 155 billion cubic meter (Bm3) (Table-2). Otherregional surface water inflow varies in the range between 30-50 Bm3. The availability offlows in the regional rivers of North-central, Southwest and Southeast region are lowerthen the other regions. Greater part of these resources that flow in the major rivers isexpensive and can only be accessible through large interventions.

Major portion of the dry season flows in the Northwest, Northeast, and Southeast regionare transboundary river flows. Transboundary inflows in the Northwest Region includeflow in the rivers Teesta, Mohananda, Dharla and Dudkumar. Principal inflows in theNortheast Region are the Barak (Surma, Kushyiara), Juri, Manu and Khowai rivers.Principal inflows in the South East Region are through Muhuri, Gumti and Feni rivers,while the Mathabhanga is the only river that enters the South West Region.

In the North-central, Southwest and South-central regions Jamuna, Ganges-Padma andthe Meghna Rivers feed the regional rivers. Inflows to the Southwest region take placethrough G.K intake, Gorai and Akandi khal while it is through Old-Brhmaputra,Dhaleswari and Loohojang rivers to the North-Central. In the Southeast region flowenters through Dakatia River from Meghna River and pumping in the Chandpurirrigation project. Inflows from major rivers in the regions have been reducedsignificantly with the continuous siltation processes of the riverbeds, offtakes andencroachment of rivers. Considering the availability of river flows it may be said that theSouthwest, South-central and Southeast region can be most beneficially served by theGanges and the Meghna rivers with large interventions like barrages and pumping.

Table 2: Major Surface Water InflowsWater in Rivers (Mcm) River Water

River Nov Dec Jan Feb Mar Apr May Total (Mcm)

Brahmaputra 23,528 15,760 12,077 9,055 10,738 16,936 32,256 120,349

Ganges 12,286 7,510 4,567 3,048 2,593 2,444 2,839 35,287

Monthly total 35,814 23,270 16,644 12,103 13,330 19,380 35,095 155,636

Source: dNWMPa/ Based on 80% dependable flows at Bahadurabadb/ Available at Harding Bridge based on 80% dependable flow at Farakka and release according toGanges Water Treaty

Surface water flows vary in time and place and difficult to conserve due to flattopography. Apart from that, surface water irrigation system in the country competes forscarce surface water resource that is available during this period. It is also used for otherpurposes like fisheries, navigation and salinity control and protection of eco-system.

Transboundary Flow ReductionOne of the problems of Transboundary River is the reduction of dependable flowsduring dry season due to upstream withdrawal of water. Many of the rivers such asGanges, Betna-Kodalia, Mohananda, Teesta, Manu, Khowai, Gumti, Ballamukh Dhara


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Figure-1


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Figure-2


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Figure- 3


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and Muhuri face acute problem of low dry season flow. Particular problem is related toflows in the Ganges as a result of dry season flow diversion at Farakka. The reduction offlows since 1975 has reduced the availability of fresh water flows in the Southwest regionrequired for salinity control and for other uses including water supply for drinking purposes.Following the Ganges Water Treaty (GWT) in 1996 it is now required to plan foraugmentation of flows in the distributeries of Ganges for the development of surface waterbased water supply in the Southwest and South-central central region.

2.3 Ponds and Surface Storages

Traditionally rural water supply to a large extent was based on protected ponds and dugwells before the installation of tubewell started in 1980’s. These are still potential sourcesfor water supply among more than 50 percent of the population for other purposes(Table-3). Approximately, there are 1,288,222 nos. of ponds in Bangladesh (BBS, 1996)having an area of 0.114ha per pond and 21.4 ponds per mouza. Re-filled during the wetseason from rain and flood, about 17- 20 percent of these ponds dry up in the winter as aresult of natural evaporation and deep percolation losses. The ponds in the higher landwith average flooding of less than 30 cm are normally filled through rainfall. Waterbodies/ponds in the medium land and low lying land with flooding of 30-90 cm or moreare filled through flood and rainfall and normally remains serviceable even after wetseason. As a result of irrigation expansion with extended drought condition, water tablelower to such extent that ponds even in the low laying areas are dried due to increaseddeep percolation in some parts of the arsenic affected area. Protection of pond bottomwith clay blanket and refilling of ponds with perennial surface water sources will berequired to reduce/compensate the losses.

2.4 Standing Water Bodies

Residual Flood Water

It is debatable whether water available in standing water bodies other than in the pondshould be considered for domestic water supply. The residual floodwater in the lowlaying areas, much of which flows through drainage khals in the regional rivers,evaporates or is lost through deep percolation starting from October until January -February. There are some water bodies available in February that do not dry up eitherdue to having low infiltration rate or because channels are closed for fisheries andirrigation. This residual floodwater on the lower land phases is a potential water bodyextensively used for minor irrigation particularly during early dry season for landpreparation, pre-watering and transplanting stages of boro. The availability of this waterto re-fill the protected ponds in the low land could also be a feasible proposition if notpolluted by irrigation wastewater.

Beel, Haor and Baor

Other large water bodies e.g. beel, haor and baor can be utilized as potential sources ofdomestic water supply in the adjacent urban and rural areas. Haors are mainlyconcentrated in the Haor Basin in the Northeast of the country in eastern Mymensinghand Sylhet Districts. Baors occur particularly in the Southwest parts of the country in thegreater Kushtia, Jessore and Faridpur Districts. Beels have the greatest density in the maindelta regions, notably in the greater Districts of Rajshahi, Pabna, Kushtia, Jessore,Faridpur, Comilla and Noakhali, as well as in the Haor Basin. These sources may be usedfor water supply in the arsenic affected areas.


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3.0 Surface Water Quality

The surface water must have physical, chemical and bacteriological quality to be suitablefor human consumption. Unfortunately surface water quality is not up to the mark andcan not be used without treatment.

3.1 Industrial Pollution

Industrial effluents are the major sources of pollution of surface water resources, whichis rendering rivers and water bodies unsuitable as drinking water sources withoutexpensive treatment. There are particularly some acute hot spots. The worst problem isin the river Buriganga in Dhaka but other rivers around Dhaka and Chittagong are alsoseriously polluted. Similar situation may arise around other cities and town in the arsenicaffected areas if this situation remain unchecked.

3.2 Poor Sanitation

Poor sanitation poses a serious threat to surface water quality in the rural Bangladesh.Only 43 percent urban and 10 percent rural households use water sealed latrines, whilevast majority of the people continues to practice open defection. Around 20,000 metrictons of excreta are released in the environment everyday. As a result surface waterquality deteriorates when increasing inflows from contaminated area mixes with thewater bodies during monsoon season, the faecal coliform concentration in most surfacewater sources have been found to be in the range of 500 to several thousand per 100 ml.The hazards of faecal contamination of ponds through hanging latrines, the siting oflatrines and location of soakpits to avoid leakage and environmental pollution requires tobe in place. The ponds are also polluted through washing and bathing, although effortsare there to reserve some ponds for specific uses. Appropriate initiatives are required toimplement total sanitation through the public awareness building campaign in this regard.

3.3 Transboundary Surface Water Quality

Apart from the availability of dependable flows, adequate quality of water, includingsediment load of the transboundary rivers are also a problem. Reduction of Ganges flowshas reduced the flow availability and thereby increased salinity in the south which is aproblem for different users including water supply for drinking purposes. Thetransboundary rivers in Bangladesh carry around 2.4 billion tons of sediments, a part ofwhich is deposited in the riverbed and in the flood plains each year. These sedimentloads creates a quality problem which makes river water unsuitable for domestic wateruse without treatment. Sediment in the Brahmaputra has increased over recent years, butthe suspended materials appear to be coarser, with a higher percentage of sand and lessorganic matter.

A significant quantity of arsenic is also transported in Bangladesh from upstream in thesolid phase sorbed on sediments. The fine-grained sediments during the post-monsoonperiod range between 4-5.5 mg/kg while arsenic load in the riverbed sediments is around1.0-4.7 mg/kg (Ref: 6). In addition, there are problems of water quality in the first flushof monsoon season flows resulting from industries and waste in upstream. Pollutionfrom a pulp mill in India in the Kushiyara catchment, a sub-catchment of the Meghna isa transboundary quality problem in the Northeast region.


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4.0 Current Status and Trends of Surface Water Use

Bangladesh has the highest rural population densities in the world and the overallcountry density is also the highest, with the exception of some city states. Most of thearsenic affected rural areas have densities of more then 1000 people per km². Watersupply information obtained during the 1991 census summarized in Table-3 clearlyshows that while piped supplies (both the surface and groundwater based) and tubewellssupplied nearly 90% of drinking water, nearly half of the population still used surfacewater sources for other purposes apart from drinking. Ground water is used for drinking,washing dishes and vegetables while low mineral content surface water is preferred forcooking, bathing and washing clothes. Tubewell water is almost never used for bathingor washing clothes (or in many households, for cooking rice) in the arsenic affectedareas. Therefore options needs to be proposed in response to these cultural preferencesin providing all-season and to meet two categories of needs in designing future watersupply system in the arsenic affected areas.

There are few number of small surface water treatment plant and a quite large number ofPond Sand Filters for treatment of mainly pond water in the country but the totalquantity of water produced by these units is very small as compared to its demand. PondSand Filters are being used as alternative options for quite some time in the coastal areaand recently rainwater harvesting is gaining popularity through the promotion by DPHEand the NGOs.

Table-3: Sources of Drinking Water SupplyPercentage of Dwelling Units Using Source

Inside tap Outsidetap

Privatetubewell

GoBtubewell

Well Pond River

Drinking water Overall 2.5 1.5 39.1 43.3 7.2 4.6 1.7Other water Overall 2.6 1.0 20.1 12.7 8.8 43.9 11.1

Drinking water Rural 0.4 0.7 38.7 45.6 7.8 5.0 1.9Other water Rural 0.4 0.3 18.9 13.0 9.3 46.4 11.8

Drinking water Urban 20.1 8.5 42.8 24.6 2.7 0.9 0.3Other water Urban 21.0 6.1 30.2 10.4 4.2 23.1 5.0 Source: 1991 Census, dNWMPP


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5.0 Surface Water Management for Safe Water Supply

Sample results from a country wide study conducted by BGS-DPHE in 2000 suggeststhat out of 64 districts, drinking water in 61 districts are contaminated by arsenic thoughthe percentage of the tubewells contaminated vary from 90% to less then 5%. Twentyseven percent of the hand tubewells in the country, spread over 268 upazilas arecontaminated with arsenic above Bangladesh drinking water quality standard of0.05mg/l. The contaminations are strongly concentrated in different parts of southeastand southwest region of the country. Upazilas along the western border of theSouthwest, large areas of the Southeast, the extreme Northeast, spots in northeast ofDhaka along the Meghna, and at points along the Ganges/Padma needs attention onpriority basis (Figure-4). The most pressing need in these areas is to provide arsenic freesafe drinking water. This can be accomplished using variety of surface water optons orsupplying groundwater from deeper aquifer or treating contaminated groundwater.

In order to select any options based on surface water in comparison with groundwater inthe arsenic affected areas, geological conditions in the area need to be considered. Thegeological conditions in the arsenic affected areas may be classed as Low Water Table(LWT) areas, Groundwater saline area/Coastal Belt (CB), High Water Table Areas(HWT), arsenic in the deeper aquifer area, area with iron in the groundwater.

In the Low Water Table (LWT) areas of Bangladesh, women cannot draw water fordrinking and domestic use by handpumps from depths below seven meters (Figure-5).So in area with extensive dry season irrigation by STWs and DTWs during the dry seasonsurface water options with piped water supply from irrigation canal or protected pondsmay be advantageously used in comparison to dug well or hand deep tube well. TheFigure-6 shows probable technology required for drinking water supply fromgroundwater sources (without considering arsenic constraints) due to full development ofagriculture land mostly using groundwater resource.

In the Coastal Belt, the shallow aquifer to a depth of 300m is increasingly saline. Mostconsumers, therefore, looks for “sweet water ponds” or otherwise they are compelled todrink salty water. The prevalence of arsenic and iron in shallow groundwater sources(Figure-4&7) are the additional constraints to the provision of potable supply fromgroundwater sources in these areas. Rainwater harvesting during the monsoon fordomestic purposes is common, but in the dry season, many remote communities sufferfrom tremendous shortages and have to survive on very little water. Protected pondsmay be the option in many such places if deep tube wells are not feasible.

In all areas, apart from the technical constraints, it is very difficult for women or girls tocarry sufficient water required for daily household requirements from far distant placesduring the dry season. On many occasions, people are forced to drink water from surfacewater sources like stream and ponds, which become contaminated than usual as manyevaporate and dry up as pumps draw down the water table. The ingestion of water frompolluted surface water sources into the ponds can result in heightened health risks.Figure-8 shows probable areas where deeper aquifer up to a depth of 200m belowground surface is contaminated with arsenic. Although based on a small size of samplethe deep well may safely be avoided in these areas.


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Source:BGS-DPHE

22oN

25oN

26oN

24oN

21oN

23oN

90oE 92oE91oE89oE

I N D I A(Tripura)

I N D I A(Assam)

I N D I A(West Bengal)

MYANMARB A Y O F B E N G A L

O - 11 - 1010-25

25-5050-7575-100

Figure –4: Percent Tube well having Arsenic Content > 0.05 mg/l


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Figure-5


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Figure-6


July 2003 14

Figure-7


July 2003 15

Source:BGS-DPHE

Figure-8


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Figure-9

Chandpur IrrigationProject

Muhuri IrriProject

Pabna Irri & Rural Dev.Project

Ganges-Kabadak Irri.Project

Barisal Irri.Project

Meghna-DhonagodaIrri. Project

Manu RiverProject


July 2003 17

In order to respond to the immediate need for safe drinking water in the affected areaimproved Dug wells, Pond Sand Filters, Rainwater harvesting and Deep hand tubewellsin the deeper aquifer, arsenic filters in the existing HTWs and Tara pumps, householdremoval arsenic facilities etc are the possible options. The above geological conditions aswell as the affordability, sustainability, equity of access to water supply and the povertysituation should dictate the choice. In the following paragraph advantage anddisadvantages of surface water options feasible in the urban and rural setting arediscussed. For the mediums to longer-term solutions access to long-term safe sources ofwater has to be ensured. In short the main options for water supply in the towns andrural areas should cover a mix of technical alternatives in the short term perennial surfacewater sources may be seriously examined for the medium to longer term.

Surface Water Schemes for Irrigation

BWDB has so far implemented about 628 projects/ sub-projects for the development ofsurface water for agriculture. Important irrigation project (Figure-9) in the arsenicaffected areas are Pabna Irrigation and Rural Development Project in Northwest region, Ganges-Kabadak Irrigation Project in Southwest region, Meghna-Donogoda Irrigation Project and,Chandpur Irrigation Project in the Southeast region and Muhuri Irrigation Project and Monu riverIrrigation Project in Northeast region. Chandpur Irrigation Project covers 6(six) upazillas.Meghna Dhonogoda Irrigation Project covers fifteen unions of Matlab (N) upazilla in theChandpur district. GK Project area comprises part of Khustia Sadar, Kumar Khali,Khoksha, Mirpur, Daulatpur and Bheramara upazilas of Khustia district, Chuadanga andAlamdanga upazila of Chuadanga district, Jhenaidah, Harinakunda of Jhenaidah districtand Magura and Sreepur upazila of Magura district. Apart from that LGRD and BADChave constructed some irrigation scheme with storage and canal system. Possibilities ofsupplying water from the irrigation canal of these projects to serve nearby urban or ruralareas with piped distribution system may be investigated.

5.1 Urban Water Supply: Options

Rainwater HarvestingRainwater harvesting in urban areas would involve collection of water from roofs foruses where potable water is not essential. Storage tanks could be incorporated in thebasements of new buildings. It is unlikely that rainwater harvesting would be costeffective for the owners of buildings unless water charges are set at a very high level.Even it is unlikely that the roof area of the building would be large enough to catch thatamount of water. Either on-site treatment would be needed, or separate plumbing wouldbe required so that rainwater is used only for certain purposes, such as washing orflushing toilets etc.

Rainwater harvesting would not reduce the maximum demand on the supply system.However, use of stored rainwater, when available, would reduce demands, and revenues,for the main supply system. In conclusion, the use of rainwater harvesting in the urbanareas may be seen as an expensive measure, which is worth investing only if there is noother surface or groundwater resources.

Piped Distribution System from Surface Water Source

Areas near perennial surface water source e.g. beels, haors or rivers, treatment works maybe installed to treat the water and distribute to the household through piped distributionsystem. Such a solution is more appropriate for urban communities, but it can also be


July 2003 18

applied to rural communities if the cost of distribution piped work can be rationalised.The feasibility of this option would depend on the competition for these water resourcesat local level and finally the costs in relation to other options available for supplying safewater.

Water resources in the rivers and streams around most of the major cities are subject tothe risk of pollution by industrial waste disposal. The resource has the difficulties ofusing it without expensive treatment. The alternative option is to use surface water fromremote point of the sources where quantity and quality are likely not to be a constraintfor the development. Planning of any intake on a major river would need ensuringchannel stability including protection against erosion. There is also a risk of the low flowchannel being shifted away from the selected intake. Location of the intake at a fixedprotected site, such as a bridge, is not always available. In-spite of that, raw river waterwill require primary treatment particularly the sediment removal and final treatmentbefore water is transmitted in the distribution system. This two-fold treatment of surfacewater is expensive.

For a river source, unless stable sites can be found, intakes on rivers may well be subjectto erosion and deposition problems, which would increase the O&M costs. In the haorsand beel areas this problem is however not present in that fashion.

Water Supply in the Major Cities of Arsenic Affected Area

Increasing demand, declining groundwater resources and rising water pollution are likelyto necessitate a major shift to bulk supplies from local sources to more distant surfacewater sources to serve major cities including Khulna. Abstraction from the Padma isunder consideration to meet the Dhaka City’s demand. Khulna could benefit fromincreased flows transferred from the Ganges, but may in the meantime abstract freshwater from further upstream

In the coastal areas where rainwater harvesting and pond sand filters are the onlyalternative solutions, such systems could be employed if fresh water supply could beaugmented in the local rivers or streams. These problems and costs would however, besubstantially reduced if intakes could be associated with other river control works.

Domestic Filtration or Treatment

Several approaches have been developed for household filtration and treatment ofsurface water to remove faecal pollutants. Oxfam and Disaster Management Unit haveintroduced the three kolshi and five-kolshi domestic filter system to remove pathogens andiron to make water more palatable and safe for drinking.

5.2 Rural Water Supply: Options

Dug wellDug well is the oldest method of water supply in rural Bangladesh. The supply source isthe surface water stored in the upper layer underneath ground surface that renewsannually through flood and rainfall. The technology has been successfully revived withsome modification in many parts of the arsenic affected areas where the water is eitherfree from arsenic or iron or their concentration is well below their acceptable limits.


July 2003 19

Dug wells may be of different types according to local conditions. A well can be dug byhand in conditions such as soil containing cobbles and boulders, where low-cost drillingis difficult. A simple dug well may be an unlined pit that extends down to the water table.Without any lining, the sides tend to be unstable. Ring wells comprise hand-dug holeslined with pre-fabricated concrete rings. It is difficult to construct dug wells significantlybelow the ground water level, so they may dry up during prolonged droughts.

A properly constructed dug well with a lining and protection against surface waterinflows called improved dug well can provide a satisfactory source of good quality water.However, water quality testing would be required, and if found contaminated, sometreatment would be needed. According to an estimate (Ref: 3) a 2m diameter dug well toa depth of 7m and lined with precast RC rings, a precast RC cover slab, a concreteplatform with drainage facility and a hand pump to serve 100 people at a consumptionrate of 50 l/c-d the capital investment cost per person benefited is about Tk660. Theannual cost per m3 of water utilized, which comprises an O&M cost and an annualizedcost of the capital invested, is about Tk5. In many places dug wells are not feasible aswater table goes down and soil conditions are not favorable.

In the recent pilot area, examples have been set of piped water supply in the ruralpopulation using safe water sources from improved dug well. Piped water supply systemin a village in the Ishwardi in Pabna district by Dhaka Community hospital is such anexample.

Small piped systems based on water drawn from pollution free surface water sources forboth peri-urban and rural areas should offer medium-to long-term water supplyimprovements, coupled with a framework for active community and private sectorparticipation with the primary focus on the poor and disadvantaged sections of society.

Improved Dug wells can usually be constructed as community initiatives. However, as itis an expensive option, government subsidies may be appropriate to facilitate a betterquality of construction. LGIs and DPHE should facilitate the construction of Dug wellsin areas where they are the most appropriate solution. Construction difficulties mayprevent dug wells from being deep enough to provide security of supply duringprolonged droughts. This option applies to any region where there is shallowgroundwater (See Figure-5) but ground conditions prevents the use of low cost drilledwells.

Pond Sand Filter

Traditionally rural water supply to a large extent was based on protected ponds beforethe installation of tubewells. In general biological quality of pond water is extremely poorfor various reasons. Due to continuous dependency on the use of tubewells people arenow reluctant to use ponds for their drinking purposes. Most of the ponds are now usedfor fish culture and become unsuitable for sand filtering if artificial fish feeding is used inthe ponds.

Slow sand filters are package type filter units developed to treat surface waters of pondsfor domestic consumption in the coastal saline belt. In this system surface waterdischarge in a small reservoir underlain by a sand bed and the filtered water is collectedthrough taps. The system popularly known as Pond Sand Filter (PSF) is one of thealternative technologies for supplying arsenic free potable water, suitable for thehousehold at village level.


July 2003 20

In parts of the arsenic affected areas where there is no other option available pond sandfilter technology for safe drinking water supply works better. If one pond per mouzacould be protected from contamination, it would provide a source of drinking water withminimal treatment. Sanitary practices of the village’s people should be carefully kept faraway from the ponds for successful use of ponds. Many of the ponds belong toGovernment. If these are transferred to the local Government so that union parishadChairmen is made responsible to take care of the pond and make it usable for the localinhabitants.

Many PSF have been installed by DPHE/UNICEF and some NGOs in areas of salineor arsenic contamination. A typical such system comprises a 0.25ha pond (2m deep) anda brick built sand filter incorporating a handpump to serve a population of 1000 peoplewith 12.5 l/c-d, after allowance is made for evaporation. The pond needs to be lined withclay or a membrane to minimize infiltration, fenced to keep out animals, and reservedonly for drinking water (no washing of people, animals or machinery). In most areas, asurface water collector system would be required to fill the pond and a minimum of 1mdepth of water should be ensured in the pond. Users would be required to refill the filterafter filling their containers to allow time for water to filter through for the next user.The filters could remove iron, arsenic and pathogens, but not salt, and in saline areas thepond would have to be filled with fresh water.

Local Government Institutions (LGI’s), would coordinate the construction of ponds andfilters with the help of DPHE or UNICEF. Operation and maintenance would require tobe undertaken by the community. Since construction would be by a Government agency,there would be major institutional constraints to rapid execution.

Construction of a new pond would require a large area of land to be acquired in eachvillage, which would take time and in many cases be refused. If an existing pond wereavailable for conversion to community use, a caretaker would need to be appointed. Onthe basis of present experience, O&M would not be carried out and the systems wouldsoon fail into despair unless the option is considered essential. The filters have to becleaned frequently to maintain full effectiveness and this is unlikely to happen. Accordingto an estimate, the capital investment cost per person benefited is about Tk180 for asystem with an existing pond and about Tk 960 for with a new pond. The annual costper m3 of water utilised, which comprises an O&M cost and an annualised cost of thecapital invested, is about Tk7.30 and Tk25.40 for the respective systems. Ponds andfilters are likely to be required only in areas where no other alternatives are available.

Rainwater harvesting

Rainwater harvesting has been adopted as a solution for obtaining drinking water incoastal areas by DPHE/UNICEF since 1994. In these systems, rainwater collected fromtin roofs or plastic sheets over thatched roofs has been channeled into large concretestorage tanks for drinking and cooking use throughout the dry season. Dependableannual rainfall in the central and east coast (Barguna to Cox’s Bazaar) is around 1200mma year, but in the West (Satkhira to Bagherhat) it is in the range 900 to 1100mm.Assuming 75% to be captured in areas with 1000mm rainfall, a catchment area of 4m2 isrequired per person. This corresponds closely with a typical roof area of say 12m2 for afamily of five to six persons. Cost estimation has been carried out for a typical system fora household to take care of the drinking requirement of 5 l/c-d. According to an estimate(Ref:3), the capital investment cost per person benefited is about Tk1500. The annual


July 2003 21

cost per m3 of water utilized, which comprises an O&M cost and an annualized cost ofthe capital invested, is about Tk100.

Rain water harvesting offers the advantage of a private rather than a shared supply andwill reduce the risks from drinking non-potable water. Cultural prohibition againstdrinking rainwater might reduce community interest. The relatively high capital costs willbe beyond the reach of many households, and substantial subsidies will be needed.DPHE and NGOs would promote rainwater harvesting in areas where it is the mostattractive solution. Provided that funds are available, rainwater harvesting facilities can beinstalled very quickly. The facilities are vulnerable to exceptionally long droughts, waterusage in excess of the assumed basic needs, or storm damage to the water collectionsystem. This option applies in areas where there is no other safe source of water. It ismost likely appropriate in coastal areas with saline groundwater.

Rural Bulk Water Supply and DistributionAn option of bulk water supply and distribution in the rural areas through a network ofpipelines carrying safe drinking water from surface water sources to towns and villages ofBangladesh where local sources are unfit for use may be worth considering in themedium and longer term.

The network would consists of an abstraction works, primary treatment (sedimentationand chlorination of water abstracted from a river), a set of second lift pumps, a trunkmain and distributary mains to each village or town. The network of pipelines would be10-50 Km long delivering to blocks of 100,000 customers and distribution network toreach 100 village centers, each center covering an area of 1km2. At the delivery point ateach center the water would be stored in an overhead tank and metered for bulk sale tothe village. Further distribution would be under local level control. Bulk water deliverywould be for 24 hours a day at the rate of 0.60 l/s/km2 to a service area 10km either sideof the trunk main. Offtakes at every 5km would supply 30 l/s through distributarypipelines (300mm diameter reducing to 100mm) each side of the trunk main to theoverhead storage tanks.

Surface water sources would be the perennial rivers, which are mostly the major riversand their distributaries. If main river barrages were built, the network of possibledistributaries would be considerably increased. Surface sources could serve many villages,but the cost of transmission would be high. Where water is being conveyed for irrigationthrough open canals these are less costly. In the coastal areas, pipelines would have totraverse rivers, which would raise costs and subject them to interruptions in supply whereproblems of erosion occur. This makes them less suitable, and for these areas theappropriate bulk carrier would be a tanker (as now used in Khulna). Tankers are apossibility, as many old tankers, no longer suitable for service, are brought to Chittagongfor dismantling each year. These might well be suitable for inland use.

According to an estimate (Ref:3) for such a large surface water supply incorporating aprimary treatment to serve 1000 villages (50 x 20km2), the capital investment cost perperson benefited is about Tk3000 for the surface water system. The annual cost per m3

of water utilized, which comprises an O&M cost and an annualized cost of the capitalinvested, is about Tk21.90. A part of the annual cost may need to be recovered throughweekly/monthly payments by the users. The BMDA already supplies water to villages inthe Barind Tract under similar arrangements, which demonstrates that the concept can


July 2003 22

be made to work. If built and operated by a Government agency, all costs would comefrom the GoB development budget. Capital costs to the Government would be reducedsubstantially if BOT arrangements were made. O&M costs would, in principle, berecovered by charging payments for water from the villagers. GoB cost recoverymechanisms are poor and it is likely that a major portion of the O&M costs would haveto come from revenue budget. Under BOT arrangements, the contractor’s responsibilitywould include collection of revenue from villages, and all O&M costs, so the costs togovernment revenue budget would be small or zero. A Government agency or a privatesector organization could operate each bulk water carrier as a separate operation, either,under a BOT arrangement. In the latter case, Government would have to provide asubsidy to allow water to be made available at the village at an affordable rate, assumingthe communities provide the land for construction of the storage tanks, etc.

The technical problem of laying pipelines is not difficult in the conditions of Bangladesh,although dewatering would often be required (costs have been included for this). Themajor problems would be getting agreement from the villagers that this was anappropriate and desirable solution, and that they would be able to pay for it. Anextensive public awareness campaign would be needed to explain the advantages andcosts. Negotiating wayleaves and getting access to land to lay pipelines would take time,and some land would be needed at the abstraction point and distribution points, and landfor maintenance.

Limitations: There are a number of major limitations of bulk water supply from surfacewater sources. Even with floating pump stations, major rivers pose a problem, as lowflow channels can be several km from the bank, and the banks themselves are subject toerosion. These uncertainties could be removed if barrages are built, as water levels aremore or less constant throughout the year. Rural pipelines would be appropriate in areaswhere local supplies cannot be used for one reason or another. These options would besuitable for arsenic contaminated areas in the Southeast, and in large parts of theSouthwest and South-central regions.


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6.0 Principles and Guidelines of Surface Water options for drinkingwater supply

In view of the above discussion following suggestion may be proposed in favor ofsurface water options for drinking water supply.

6.1 Policy Principles to be adopted:

1) Surface water development will enhance the contribution of the arsenicmitigation program in the arsenic affected areas;

2) The approach of arsenic mitigation requires integration of options using surfacewater sources under the overall water resources development and management;

3) All possible options and technology that could be developed using surface waterresources will have to be investigated with fullest effort;

4) In the selection of options, geological situations e.g. Low water table, iron ingroundwater, drought affected area, salinity and arsenic in the deeper aquifer etcmay be considered;

5) Final selection would however be based on demand-led approach in which allstakeholders would be consulted before specific actions are agreed;

6) Options. e.g. improved dug well, pond sand filter, rain water harvesting etc. willbe explored in the first instance. Deep tube wells may be the last option to beexplored where other options are not feasible;

7) The private sector will be encouraged to participate in the water sector activitiesof water supply in both rural and urban areas;

8) Management of different types of village water supply should be agreed uponwith the villagers through consultation;

9) Increased women’s participation in the water schemes, management andoperation of local water supply and sanitation schemes needs to be ensured;

10) Appropriate framework of regulation, incentive and pricing should be introducedin the water supply sector;


July 2003 24

6.2 Guidelines of Framework Plan for using Surface Water as Drinking WaterSources

1) An effective structured means of decision making may be evolved for a transparentmethod of option selection. It should serve an ideal platform for participatoryplanning involving stakeholders, technical expert and analysis;

2) Surface water options may seriously be examined in the area of “ambiguity” i.e. noimpermeable layers separating upper arsenic contaminated aquifer from the deeperaquifer or there is trace of arsenic found in the deeper aquifer;

3) Once an option is finalized women representative at community level may beinvolved in the consultation for finalizing selection of site;

4) Dug well has been demonstrated a suitable surface water option for communitybased piped distribution system by Dhaka Community Hospital in Ishurdi, Pabna.This may further be examined and replicated elsewhere under similar geologicalconditions;

5) In an area where groundwater table is likely to remain above 7m in future in thedriest month of a year dug well will not dry out in the near future and therefore maybe considered a suitable option. In the area of extensive groundwater irrigation bySTWs and DTWs, it is likely that extensive drawdown will effect the lowering ofwater level in the dug well. Therefore in the area of surface water irrigation theoption may be attractive;

6) Expertise need to be developed on improved technology of dug well construction,flexible intake pipe development, especially in difficult soil and water levelconditions;

7) The option of dug well is not a good one in areas of shallow peat soil where watertaste and smell bad;

8) A standard design of improved dug well, Pond Sand Filter (PSF), rainwaterharvesting and also bulk water surface water supply with their protocol for optionchoice may be prepared;

9) In order to rejuvenate ponds for safe water supply, surface water collector systemwould be required to be installed to re-fill the ponds during the driest period of theyear;

10) Existing ponds on government owned land or privately owned ponds may be takenby the government on long term basis for the community water supply. LocalGovernment Institutes (LGI’s) may be assigned to motivate people and operate andmaintain the ponds;

11) Reversion to ponds for drinking water supplies would only be feasible if reliablefilters could be installed and maintained. In this case pond sand filter in Patherghataof Barguna is an example;


July 2003 25

12) Rainfall harvesting is a costly investment for an individual and not likely to provideround the year potable water supply in a villages. Therefore Government shouldprovide free or subsidized technology in the area where the option is absolutelynecessary;

13) Bulk supply of surface water resources in the town and large urban cities should beemphasized wherever there is opportunity of using perennial surface water sources;

14) Surface water irrigation projects in the arsenic affected areas have already built-incanal system for irrigation water supply from perennial sources. The system may beexamined if the irrigation canals can be used as delivery network for the surfacewater supply in the urban and rural areas where deep tube well and other option isnearly impossible;

15) The screening program of BAMWAS-DPHE should also incorporate an inventoryof existing dug well, ponds, protected ponds and their status at village level to assistthe selection of the option;

16) Government investment in the non-arsenic area for water supply may be diverted tothe arsenic affected areas for the promotion of surface water options having longer-term prospect. Government initiatives in the surface water option in the short termmay be promotional which is expected to be taken over by the private sector in themedium term;

17) A major public awareness campaign will require to be targeted at non-literatewomen and forge linkage between information and non-literate communities tosensitize the value of water, a more productive way of its use and its conservation;

18) Local Government will be needed to be strengthened and will increasingly take onmanagement of local water resources, water supply and sanitation developments,urban and peri-urban services. DPHE and LGED will support this effort andbecome progressively more accountable to LG at zila level and below.


July 2003 26

7.0 Recommendation

1) Improved Dug well has been proved a suitable surface water supply option inmany areas where water table remains within suction limit, well do not encounterpeat soil layer and yield from the well is sufficient for drinking purposes duringdriest part of the year. Improved Dug well as sources with community basedpiped distribution system as demonstrated by Dhaka Community Hospital inIshurdi, Pabna may be replicated under similar geological conditions followingthe guidelines approved by the National Committee of Experts on Arsenic;

2) Reversion to pond use for drinking water supplies is a feasible option in areaswhere other pure drinking water sources are not available, land is procurable,equipped with reliable filters that could be maintained properly and there issufficient rainwater or other surface water sources available for refilling theponds. Such an example of Pond Sand Filter (PSF) in Patherghata of Bargunacan be replicated in other places following the approved guidelines. Existingkhash ponds in a union may be procured on lease for long term. Private pondsmay also be utilized on rent basis for the community water supply. These pondsmust not be used for commercial fish culture or for bathing, washing except fordrinking purposes. Supervision by the Union Parishad Chairmen is likely togenerate good O&M practices with this option. Ponds may be refilled by usingirrigation canals;

3) Rainwater harvesting is likely to provide potable water supply round the year toindividual family in a village if sufficient storage facilities are available and storedwater is used wisely. Government may be involved in promotional activities topopularize the option in general and subsidize the technology where it isabsolutely necessary;

4) Other surface water sources: Network of irrigation canals of different irrigationprojects may serve adjacent town, growth centers and villages to supply perennialsurface water with piped distribution system. Surface water irrigation projects likeMeghna-Donogoda Irrigation Project, Pabna Irrigation and Rural DevelopmentProject, Chandpur Irrigation Project, G. K Project etc covers a large area witharsenic contaminated groundwater. The option of using irrigation network withperennial surface water sources in the medium term would be very much in linewith the option of using Major River water through Barrage and pumps in themedium to longer term. A pilot project may be under taken in this regard;

5) Nearly half of the population still uses surface water sources for purposes apartfrom drinking. Surface water is preferred for cooking, bathing and washingclothes. Therefore options selection may be made in response to these culturalpreferences in providing all-season and all purpose future water supply system inthe arsenic affected areas;

6) The poor especially the women suffer disproportionately when water supplyservices are poor. The quality services of surface water supply for drinking anddomestic uses should gradually be transformed to piped distribution system;


July 2003 27

7) Poor sanitation poses a serious threat to surface water quality in Bangladesh.Protection of fresh water sources from domestic pollution through buildingpublic awareness for improved sanitation and protection of surface water sourcesshould be considered for the development of surface water based drinking watersupply;

8) Industrial effluents, the major source of river pollution is required to be broughtunder control. Government should undertake cleanup program for the pollutedrivers and other water bodies. Polluters may be required under law to pay for thecleanup of water body polluted. Augmentation of fresh water flows in thepolluted rivers may be required to rejuvenate the quality of river water for watersupply purposes. Study may be conducted to see if diversion of fresh water toBuriganga and other rivers around Dhaka can improve the water quality of theriver Buriganga as envisaged in draft National Water Management Plan(dNWMP), 2001;

9) Legal and regulatory framework may be developed to help the process ofconservation of water bodies and its management and improve the investmentclimate for the private sector in surface water development and management;

10) The surface water resources available for water supply are widely distributed intime and space in the arsenic affected areas. A systematic approach is required fora water supply plan integrated with overall water resources development andmanagement plan;

11) In most cases surface water requires treatment before it can be used for drinkingpurposes. Research may be conducted to improve the existing technologiesincluding the improvement of small-scale water treatment plants and make themaffordable to the poor. Water quality monitoring of surface water sources in asystematic and regular basis is a prerequisite for the development of surface waterbased water supply system;

12) The surface water resources available for water supply are widely distributed intime and space in the arsenic affected areas. A systematic approach is required fora water supply planning integrated with overall water resources development andmanagement plan;


July 2003 28

REFERENCES

1. Development Strategy for the NWMP, Water Resources Planning Organization,Ministry of Water Resources, Government of the People’s Republic of Bangladesh,June 2001

2. National Water Management Plan (draft final), Water Resources PlanningOrganization, Ministry of Water Resources, Government of the People’s Republic ofBangladesh, December 2001;

3. Water Supply Options, National Water Management Plan Project (NWMPP), August2000;

4. Basic Human needs, National Water Management Plan Project (NWMPP), August2000;

5. Datta, D.K. and Subramanian, V. Texture and Mineralogy of Sediments from theGanges-Brahmaputra-Meghna River System in the Bengal Basin, Bangladesh andTheir Environmental Implications. Environmental Geology, 1997; 30,181-188;

6. Chowdhury, M.A.I., Ahmed, M. F. and Ali, M.A. Influence of Upstream Sediment onArsenic Contamination of Groundwater in Bangladesh. In: Fate of Arsenic inGroundwater, Ahmed et.al (Editors), Bangladesh University of Engineering,Bangladesh and Technology and United Nations University, Japan, February, 2003;21-36

7. K. M. Minnatullah, Total Sanitation: A prerequisite for the Sustenance of FreshwaterResources in Bangladesh;

8. LGD, MoLGRD&C, draft National Policy for Arsenic Mitigation, 2003;

9. LGD, MoLGRD&C, draft Implementation Plan for Arsenic Mitigation inBangladesh, 2003.


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Annex

Report of the Committee on Surface water Development and Management for Drinking water Supply in the Arsenic affected areas of Ba

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Appendix-apendix-a
ngladeshAp
30

Report of the Committee on Surface water Development and Management for Drinking water Supply in the Arsenic affected areas of Banglade

July 2003

sh

Appendix-b

31


July 2003

Appendix-c

32


July 2003 33

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