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Dams andstakeholders

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Dams - large and small

Although dams have been built in the world since timesimmemorial, large dam construction was earlier notpossible though needed, because of lack of adequatedesign knowledge, construction equipment, newmaterials like cement and concrete and technology ofconstruction. Also, economic conditions and institutionalcapacity existing in countries that needed large dams,did not enable them to take them up. The large damconstruction became possible during the 20th centurymainly because of advances made in Science andTechnology, which enabled mechanisation ofconstruction processes and speedier construction.Improved design procedures and new constructionmaterials enabled the design of larger dams and theircomponents to take on much higher loads and stresses.Also, the needy countries had mobilised finances and

built up their capacity by then. Large dams, distinct fromsmaller ones, enable larger storage of water at suitableplaces, thus saving on multiplicity of efforts which wouldbe needed to construct several smaller ones. Largerwater storages were also found to be necessary by thesociety in response to the needs of the growing urbanand industrial centres, generation of hydropower or foragricultural support.

Main stakeholders

The large dams enable harnessing of large waterresources potentials, where and when available, tomeet needs of fast growing societies round the world:food, fodder, fish production (aquaculture), drinkingwater, clothing fibres, sanitation, energy, industry, wildlifeand others. After several decades of evolving damconstruction activity, even todays needs are far fromsatisfied in many developing regions. These people ofthe world comprising, farmers who grow food; industries,municipal institutions who use water stored behind the

dams, besides the governments who promote waterresources development (WRD) are major stakeholdersin dams which have been so far built. The need for moredams, especially in developing regions of the world, isstill enormous. Societies for whom these dams arecrucial for existence have therefore to be considered asthe most important stakeholders.

Large dams, distinct from

smaller ones, enable larger

storage of water at suitable

places, thus saving on

multiplicity of efforts which

would be needed to construct

several smaller ones.

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Affected people

Plans and efforts have been made during the last 2 - 3decades to see that the people that are adverselyaffected due to dams are involved in the developmentprocess and are treated as stakeholders. However,there are people and organisations who feel stronglythat not enough is being done by governments and

society while building dams to mitigate their hardshipsand conserve or improve the environment and ecology.The affected people, undoubtedly, have to be consideredmajor stakeholders alongwith those who are benefitedfrom the dams.

Dam builders, funding agencies and professionals

The planners and builders of dams, users of water,supported by sociologists, economists, politicians who

promote dams form another group of stakeholders.There are several associations of these stakeholders.Three majors of such world bodies are :

* International Commission on Large Dams(ICOLD) established in 1928;

* International Commission on Irrigation andDrainage (ICID) established in 1950;

* International Hydropower Association (IHA)

established in 1995.

There are some 10 similar world-wide associations ofprofessionals dealing with some of the aspects of damswhich can extend help in the matter, wherever required.Recently (1998) the World Commission on Dams (WCD)has been established.

ICID

Sustainable irrigated agriculture, drainage of rainfed

crops and of irrigated land, and flood control andmanagement - comprise the main action thrusts of theICID. All these are directed to ensure continued foodsecurity through improvement and extension of irrigatedand drained areas, increase in productivity andtransformation of the rural development scenariothroughout the world. A recent report from the

After several decad

evolving dam constr

activity, even todayare far from satisf

many developing re

The affected peo

undoubtedly, have

considered maj

stakeholders alongwi

who are benefited fr

dams.

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International Water Management Institute (IWMI)indicates that even with best irrigation efficiency, theworld needs an extension of irrigated areas by buildingmore dams and storages. To achieve these objectives,ICID acts through its country membership, which atpresent includes 87 countries. Together they accountfor 95% of the total irrigated area which contributesabout 40% of the world food production. It has more

than 25 work bodies comprising international expertsdealing with some of the issues related to the role ofdams for irrigation, drainage and flood control. Thethemes covered by these bodies include EnvironmentalImpacts of Irrigation, Drainage and Flood ControlProjects, Socio-economic Impacts and Policy Issues,Research and Development, Irrigation and DrainagePerformance, Sustainable Use of Natural Resourcesfor Crop Production, etc. The ICID gathers world wideexperience through these work bodies, draws lessons

and builds them in its strategy for future action.

ICID aims to provide better management for theagricultural lands of the world through the application ofscience and techniques of irrigation, drainage and floodcontrol measures. In pursuing its aims, ICID embracesthe sound principles of socio-economic values andenvironmental management. The welfare of the peopleand preservation of nature are at the heart of itsconcerns. Dams of all sizes - small, medium and large

are an essential component of overall and integratedwater management systems. They divert water, theyretain it over long periods of time to use it effectively andthey attenuate floods and alleviate impacts of droughts.They relieve drainage congestion, and they provide forthe timely and continuous supply of irrigation waterneeded to meet the demands of crops and livestock.Existing and new dams will continue to play a major rolein the management systems.

Sustainable irrigated

agriculture, drainage of

rainfed crops and ofirrigated land and flood

control and management

comprise the main action

thrusts of the ICID.

In pursuing its aims, ICID

embraces the sound

rinciples of socio-economic

values and environmentalmanagement.

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A Backgroundon Dams

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Large dams

Under what situations large storages are necessaryand feasible for promoting irrigation, drainage or floodcontrol vary according to agroclimatic setting. All damsstore behind them flood-waters, primarily for the benefitof human beings. ICOLD defines large dams as thosemore than 15 m in height, while including smaller dams

up to 10 m height as well, if they are otherwise significantwith respect to storage volume, density of population,etc. The classification is notional. But because of theeffects of scale the larger a dam is, the lower will be thecost of a unit of water stored.

Choice and size

The storage of water enables removal of mismatchbetween variable availability and supply, but usually

more is demanded round the year. For this purpose,many reservoirs are designed to carry over storage tothe next season as well. The variability, if not taken careof by such storages, results in droughts and/or floods.All dams - large and small and mega to micro, amelioratesuch conditions and serve similar purposes. All damsfacilitate transport of water to deficit areas by means ofopen canals, tunnels or closed pipelines. In a riverbasin, a judicious combination of large and small damsmay be required to store water for facilitating withdrawal

and use with minimum transport distance to demandregions. The choice of large or small dams and locationfor each dam depends on several factors includingtechnical feasibility, location of water deficit regions thatneed to be serviced and alternatives available for thepurpose. Besides, the balance of advantages anddisadvantages due to a particular dam in socio-economic and environmental aspects helps in decisionmaking.

Storage and quantities for beneficial uses

Not all the water stored behind dams is withdrawn foruse. A top depth varying from 1 to 2 meters dependingon local climate, is annually lost to atmosphere due toevaporation. At the bottom, some depth serves as adead storage for accommodating sediment brought in

Storages provide insurance

against uncertainty due to

limatic variability, can help

educe variability in seasons

low flows in rivers and

asically save societies from

economic upheavals and

losses due to flood and

drought.

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by inflow. Similarly some silt does accumulate in higherreaches where inflows merge into the reservoirperiphery, gradually building up small deltas of sediment.Gated crests obviate this loss of storage to a significantextent by allowing opening of gates when inflows containhigher levels of sediment. The remaining volume minusthe seepage from the bed of the reservoir and thatacross the dam foundation and body, is available for

transport and supply for different beneficial uses. Deadstorage size depends upon the catchment areacharacteristics but similar to evaporation losses, tendsto be proportionately more in case of a smaller dam.

Storages provide insurance against uncertainty due toclimatic variability, can help reduce variability in seasonslow flows in rivers and basically save societies fromeconomic upheavals and losses due to flood anddrought.

Disadvantages

Every dam causes partly temporary and partlypermanent submergence of land in the upstream anddisplacement of resident persons and their propertygenerally, along-with submergence of plant life anddisruption to animal life. As reservoir levels recede, thesubmerged land - rich with fertile soil and silt depositscan produce valuable crops. Also downstream of dams,such effects are caused by ancillary facilities on a

similar but much smaller scale. The consequent socialand economic loss is generally assessed and comparedwith benefits due to the dam. The downstream uses aremet with mostly from flow by gravity or regulatedreleases into the river, whereas in the upstream, liftingof water is involved.

All these disadvantages have to be assessed in advanceto plan ameliorative measures. During implementationof the plan and during operation, each disadvantage

calls for careful management and monitoring.

Withdrawal for irrigation

A major portion of water stored behind dams in theworld is withdrawn for irrigation which mostly comprisesconsumptive use, that is, evapotranspiration (ET) needs

All the disadvantag

dams have to be asse

advance to plan ame

measures.

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due to a dam, reducing flood hazard due to inundationof land, crop and property which might result intoeconomic upheavals. It also reduces congestion ofrunoff in plains and coastal lands. Dams, reservoirs,flood levees, embankments, and river training worksconstitute structural measures for better floodmanagement. However, non-structural measures likemonitoring of precipitation, river and reservoir stages

and flow measurements, forecasting, early warning,appropriate disaster warning and strategy, also areimportant in flood management. In the lean season, theriver flow in the downstream reduces depending onwithdrawals from dams through canals or pipelines,however, it can be augmented with supplies fromupstream withdrawals. Reduced frequencies of floodsand reduced peak flows reduce the agricultural andnon-agricultural losses. On the other hand, if storage isused for generation of hydropower in the river bed, then

seasonal flow is enhanced ameliorating severaldifficulties downstream. Intensive economicdevelopments have been realised, for instance in theareas of Damodar, Mississippi, Missouri, Nile, andTennessee rivers, only because of flood protection bythe dams.

Standards

The various professional institutions/associations,

Governments and the academic sector have, during thelast century, developed criteria and guidelines for allaspects of decision making as related to dams. Presentday standards are a result of continuous review andupgrading through experience and generatedknowledge. The standards help assess availability,variability, statistical dependability, storage size, riskanalysis about chances of hydrological failure,multipurpose sharing of reservoir space, sharing ofcosts, environmental checklists, monitoring of

environmental effects, mitigation measures andeffectiveness of development effort, in addition to thenumerous Science and Technology based procedures,methods and design of structures and their components.All storage dams proposed to be built for identifiedpurposes therefore aim to conform to the approvedstandards.

Present day standard

result of continuous

and upgrading, th

experience and gen

knowledge.

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Decommissioning of dams

The question of decommissioning of dams built forirrigation purposes hardly arises because of continuingfood requirements. On the other hand, in many situations,raising and strengthening of dams is called for, forimproving the irrigation service. Dam builders have notsufficiently considered so far, decommissioning of dams

as a necessary step. Dams are complex and majorstructures involving large investments. Some dams canprove less effective than most, but efforts have beenmade to minimise the reasons for this and increase theeffectiveness through modernisation and rehabilitationof such dams. At some places a larger dam has beenbuilt in the downstream of an existing dam incidentallysubmerging it. When a reservoir gets silted up over aperiod of time, the dam has been used to work as adiversion structure for run of the river withdrawals,

sometimes for shorter period of time. The operation andmaintenance costs for an older dam are often very lowbecause of the sunken character of investment cost.

Sustainability of development due to dams

The subject of sustainability of development has beenextensively debated over the last two decades. Damshave solved many problems of communities served andhave provided basis for economic development that

has sustained itself. Employment opportunities havebeen generated, incidence of poverty has been reduced,rural population including nomads has been stabilisedlocally and migration of rural unemployed population tourban centres has been reversed. Food security to evergrowing population, protection from floods and droughtsto chronically vulnerable areas and generation of thecleanest form of energy, namely hydropower, are someother benefits of water resources development. Manyurban and industrial centres have been provided with

water supply for consumption and transport of waste fortreatment.

Gated reservoirs provide for less submergence in totalityof long term sustainability of the irrigation service byavoiding excessive silting above the crest of the spillway.A substantial part of that storage quantity stands almost

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perpetually guaranteed. Navigation, fishery, irrigatedforestry, recreation and leisure are some other obviousbenefits. The overall development due to dams is therefor everybody to see. Benefits, costs and risksundoubtedly increase with size of a dam. Efforts aremade by dam planners to maximise benefits, minimisecosts and build in defensive measures in damcomponents to take care of risks by deploying appropriate

technology and design features. Incidents involvingdam failures are decreasing from decade to decade andthe safety record is likely to be better than in many othersectors of infrastructural development. Dam safetyconcerns and policies have been incorporated in damengineering from concept to O&M stage and this hasshown positive effects on the performance of dams.Thus, structural safety of high dams is no longer a realconcern.

Compensation for affected population

The adversely affected people due to a dam comprisethose who are displaced due to inundation in the reservoiror due to ancillary structures. Some people dependenton those displaced are also incidentally affected. Somefarms develop waterlogging due to canal waters and theconcerned farmers are also affected. These peoplehave to be rehabilitated and resettled with duecompensation and recognition for their sacrifice. Such

rehabilitation and resettlement (R&R) effected in theirconsultation and with their consent can also includepartnership and ownership in the facilities and providethem economic benefits flowing from the water resourcesdevelopment. Very liberal R&R policies/guidelines havebeen framed by several developing countries whichprovide for appropriate compensation measures for theproject affected population.

The canals generally run along a contour and provide

irrigation water by flow in a command area. For farmerswho are on higher level than the canal, and similarlythose on the fringe of reservoirs, lift irrigation facilitiescan be provided, if so desired by either affected peopleor those who are close to the facilities. While thesupplies through the canal could be seasonal, thosedirectly by lifts from the reservoir are more assured and

Adversely affected

have to be rehabilita

resettled with d

compensation a

recognition for t

sacrifice

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available almost round the year. The equity in suppliescan thus be provided at local and regional level byapplying some basic economic principles. However, it isoften seen that social - more than economical - concerns,provide clues to bring equity to the project people.

Summing up

While large quantities of fresh water are yet flowing toseas through rivers, scarcity is engulfing many countriesof the world. Thousands of dams are still to be built tostore water and make it available, during the nextcentury on a world wide basis, especially in the non-industrialised countries of Asia, Africa, Latin Americaand East Europe. The needs of growing populations,the pace of urbanisation and industrialisation, and theurgent need to improve the standard and quality of lifeof poorer strata of their societies calls for urgent steps

to build these facilities. It is an enormous challenge todecision makers, developers and designers to developeconomically required capacity in an environmentallysound and sustainable way.

Thousands of dams are still

o be built to store water and

make it available during the

ext century on a world wide

basis, especially in the non-

industrialised countries

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ICID's Position

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sustained nature to meet needs of future generations aswell, and should not be of transient nature to addressonly present day concerns. ICID fully underlines therecommendations of the Rio Conference and activelypromotes their implementation. Recently, the GlobalWater Partnership has come up with the followingdefinition of Integrated Water Resources Management,a process which aims to ensure the co-ordinated

development and management of water, land and relatedresources to maximise social and economic welfarewithout compromising the sustainability of vitalecosystems. For instance, in case of dams, the presentdecisions ought to result into outputs for a long enoughtime. It is possible only through integration of developmentand management of water resources (IWRDM) which isenshrined in Agenda 21. While achieving it, quality andquantity i.e. sustainability of natural resourcesthemselves must not be affected. Dams have a finite life

like any other man-made structure. The right combinationof large and small dams in a river basin, which providessuch sustained fruition throughout the structures life,has to be ascertained by scientifically oriented specificstudies. The IWRDM has to address the needs of theultimate stable size of global population expected to bereached, hopefully, by the middle of the next century.Such needs can be met with from basin-wise availability,through the desired combination of dams to provide amodel for sustainable development. Within a basin

itself, conflict of interests often manifests due to perceivedshortages regarding size of dams. Appropriate policiesand guidelines are called for to resolve such conflicts.

Appropriate policies and guidelines also on sustainabilityaspects of dams need to be fully developed, and wheredeveloped they need to be uniformly applied. Basicallydams store flood runoff of the rivers and make thestorage available for withdrawal to meet with beneficialneeds. Within the range of variability of availability,

appropriate withdrawals are designed to import sustainedsupplies and hence sustained productivity. The watersof a basin thus get redistributed at minimum economiccost and hence ensure sustenance of the source as wellas fruits for development.

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Integration of options

The alternative to such discrete combination, asproposed by those who oppose large dams, is to go infor minor dams and micro river basin developmentschemes only. The minor dams have a definite role toplay in a basin, along with major dams. Micro river basindevelopment basically is useful in rainfed areas, which

cannot be served by canals starting from dams or bygroundwater facilities. About half of the sown area in theworld is likely to remain dependent on rains. For sucharea, micro river basin development usefully providesprotection from variability in rainfall in a rainy season. Itensures fair growth of one crop, by retaining soil moistureover a longer period and increases yield. Unfortunatelydue to agro-climatic factors such as: rainfall intensity,extent, frequency, duration and antecedent conditionsof moisture availability in soils, the rainfed agriculture

remains sustainable in a very narrow range ofdependability. Also, evaporation rates in concernedareas restrict availability of supplemental moisturedrastically.

The dams and the micro river basin development arethus not alternatives, but are complementary to eachother to increase food productivity of cropped land andto ensure food security in irrigable and rainfed lands.The total amount of water remaining available in a basin

with small size reservoirs is considerably lower due torelatively large scale evaporation, than that from a riverbasin with larger water storages.

It is ICID's position that micro-development schemesought to be considered and conceptually developed forareas which will remain rainfed as part of an integratedevaluation process that progresses toward an optimisedriver basin development scheme. It is considered to beshortsightedness, as also inappropriate, to reject large

dams, or any other component of a proposed river basindevelopment scheme without even-handed andcomprehensive analyses of overall relevant social,economic and environmental considerations.

Dams and micro river basin

development are not

alternatives, but are

omplementary to each other

o increase food productivity

of cropped land and to

ensure food security in

irrigable and rainfed lands.

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Issues related with planning, implementation,socio-economic aspects

Decision support systems

Planning and implementation of different facilities createdfor land and water development have evolved over thelast 100 years utilising advances made in science andtechnology. For micro river basin development also,sufficiently detailed criteria have been developed overthe last two decades. Spatial decision support systemshave been developed to take into account hydrologic,land use, bio-mass, energy and socio-economiccomponents for river basins. In view of low foodproductivity of rainfed areas under various climatologicaland soil conditions, several countries have taken upsuch development. Appropriate decision support toolsfor analysing and, if favourable, implementing waterresources schemes involving large dams, should bedeveloped, with due regard to overall national interests,individual basin plans, safe designs and strict monitoring.

Economic analysis

Socio-economic impacts of large dams and alternativesof micro river basin development have been studiedextensively. As mentioned earlier, the larger a facility,the benefits, costs, and risks are usually larger. Butwhile planning a facility, effort is made for maximising

benefits and minimising costs and risks. A view is taken,on the balance, of advantages to the community. Thebenefit cost (BC) analysis has to include social benefit-and cost streams to expand it to Social Benefit CostAnalysis (SBCA). It is difficult to accurately quantifysecondary and incidental benefits and costs. The SBCAessentially helps a planner to prioritise projects forimplementation besides improving dimensioning of ascheme and selection of the best alternative.

Prioritisation

For many countries of the world, all the planned storagefacilities are required and still the level of water supplymay remain short of their ultimate requirements. In suchcases, the BC analysis does not help beyond prioritisationin face of resource crunch, because even the most

Appropriate decision

tools for analysing

favourable, implem

water resources sch

involving large dams

be developed, with

regard to overall na

interests, individua

plans, safe designs a

monitoring.

The benefit cost (

analysis has to includ

benefit- and cost streexpand it to Social B

Cost Analysis (SB

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on the other hand reduces environmental degradation.The positive impacts on environment are manifold. Inabsence of a dam or a water withdrawing facility, theenvironmental degradation continues unabatedespecially in less developed regions because ofpopulation pressures. Environmental impact studiestherefore have to be carried out for both, with andwithout dam scenarios. The environmental cost of

constructing a dam is normally smaller than that in asituation without the dam, if the continued degradationin absence of a dam due to poverty and populationpressures during the life of the dam, is considered. It isoften to be concluded that the environmental cost ofbuilding and using a dam in a developing country issmaller than that of not doing that dam project. Theextent of submergence and evaporation loss from alarge storage project is lesser than that from a series ofequivalent small storage projects.

Apart from assessment of adverse impacts with andwithout a dam, it is sometimes required to carry out theassessment for situations before and after completionof a dam project as one time exercise. Both assessmentsare important as they provide important insight into theenvironmental concerns and their containment.

The checklists

The components of environmental impacts normallyconsidered are: loss of land and biomass, forest etc.due to submergence, likely loss of land due to water-logging and salinization in irrigation command,deforestation in the command due to bringing of newareas under cultivation, loss of passage for fish andaquatic life, reduction of flow in the downstream riverportion, and effects on flora and fauna in estuaries andmangroves regions. All these effects can be amelioratedby means of adoption of appropriate mitigation measures.

A checklist enables the planner to identify items of

environmental concerns that are site specific. The ICIDchecklist encourages the authorities to embark uponstudies to assess likely impacts on each of the identifiedaspects qualitatively and quantitatively. Such studies atproject stage enable assessments of costs/benefits dueto positive and negative impacts including measures tominimise, contain or compensate them.

The ICID checkencourages the autho

embark upon stud

assess likely impacts

of the identified as

qualitatively an

quantitatively

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Development of internationally acceptable criteriaand guidelines

The development of dams in the world has not takenplace in absence of knowledge. Large volume ofexperience is available. The ICID, ICOLD and IHA withthe help of their participating member countries aroundthe world, for instance, have developed a variety of

standards and guidelines. They have been adopted ininternational and professional fora and fine-tunedespecially during the last 50 years. Besides, most of thecountries have their own standards which are statutoryand hence adopted by dam professionals. The standardsand criteria adopted by any one country for its conditionscan not be made applicable to another country. Thus,while only the general guidelines could beinternationalised, much of the standardisation work hasto be done by a particular country within the country to

suit its prevailing conditions with due regard to thesafety requirements and mandatory procedures.

Institutional policy and financial arrangements forequitable sharing of benefits, costs and risks

One principle that ought to be followed is that all thosewho are benefited or who are adversely affected by damprojects are made stakeholders of the project so thatthey get a share in the benefits equitably. The standardof living and quality of life of those adversely affected

due to a dam, should be brought up to a level higher thanwhat it was prior to the dam project. Risks to thestructure due to deficiency in planning, implementationor natural hazards have to be evaluated and integratedin the cost streams, which should include ampledefensive and mitigation measures. They have to beappropriately worked out and provided in the overallplanning of the area. Again in this case, ICID believesthat the risks to the downstream society due to floods inabsence of a dam are much higher, than the risks after

construction of a dam. An appropriate assessment ofthe status of society with and without dams has thereforeto be made, according to already well definedassessment procedures whose implementation has tobe pursued by all responsible segments of society.

While only the general

guidelines could be

internationalised, much of

he standardisation work has

to be done by a particular

ountry within the country to

uit its prevailing conditions

with due regard to the safety

equirements and mandatory

procedures.

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