Dams andstakeholders

2

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 andbuilt 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 today’s 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 thedams, 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 fromsmaller ones, enable largerstorage of water at suitable

places, thus saving onmultiplicity of efforts whichwould be needed to construct

several smaller ones.

33

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 andsociety 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 whopromote 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 rainfedcrops 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 decades ofevolving dam constructionactivity, even today’s needs

are far from satisfied inmany developing regions.

The affected people,undoubtedly, have to be

considered majorstakeholders alongwith thosewho are benefited from the

dams.

4

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 morethan 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 lessonsand 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 it’sconcerns. Dams of all sizes - small, medium and largeare 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 irrigatedagriculture, drainage of

rainfed crops and ofirrigated land and floodcontrol and managementcomprise the main action

thrusts of the ICID.In pursuing its aims, ICID

embraces the soundprinciples of socio-economicvalues and environmental

management.

55

A Backgroundon Dams

6

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 damsup 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 usuallymore 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 withdrawaland 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 insuranceagainst uncertainty due to

climatic variability, can helpreduce variability in season’s

low flows in rivers andbasically save societies from

economic upheavals andlosses due to flood and

drought.

77

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 fortransport 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 season’slow 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 asimilar 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 disadvantagecalls 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 disadvantages ofdams have to be assessed inadvance to plan ameliorative

measures.

8

of irrigated crops and plantations. On the submergedland, there are often possibilities for seasonal irrigation.A majority of dams built in the world are multipurpose innature, but irrigation is the largest user of the waterswithdrawn. This does not necessarily mean that irrigationis also the biggest user of storage. The dams wereresponsible a few decades ago, for bringing undercropping, additional areas and ushering in the greenrevolution through high yielding crops and application offertilisers, imparting food security in the face of ever-growing population. Water used in excess of ET needs,however appears in the system as surface or groundwater, albeit with degradation in quality, mainly due tofertilisers and pesticides, besides minerals drawn fromsoils. Such waste has to be minimised. But for ripariansdependent on lean season flows, the deficit has to bemade good with supplies from upstream withdrawals.

Non-irrigation withdrawals

A much smaller portion of storage is withdrawn fromreservoirs and supplied for drinking, municipal andindustrial purposes, hydropower generation, etc. Of thiswithdrawal, only a very small portion is consumed byevapotranspiration. A larger portion is not consumedand is returned to the system. Wastewater from municipaland industrial withdrawals is of degraded quality. Suchwastewater has to be treated for quality improvementand reuse to increase availability for downstream uses.These uses are mounting with economic developmentround the world and are considered on priority whileplanning withdrawals for different uses from a limitedstorage. Even in ultimate stage, these uses will remainlow and can be taken care of through recycling of wastewaters. Drinking water requirement is given top priorityby most of the countries in their policy documents.Similarly, use of stored or diverted waters for hydropowergeneration is considered most eco-friendly, because ofits non-consumptive nature and because the resourceis renewable and can be used again and again in thedownstream for power generation.

Floods

The total quantum of flow and size and frequency ofpeak floods in the flood season reduce in the downstream

A majority of the dams builtin the world are multipurpose

in nature, but irrigation isthe largest user of the waters

withdrawn.

99

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 stagesand 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, thenseasonal 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 ofenvironmental 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 standards are aresult of continuous reviewand upgrading, throughexperience and generated

knowledge.

10

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 thathas 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 withwater 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

1111

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 appropriatetechnology 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. Suchrehabilitation 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 provideirrigation 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 peoplehave to be rehabilitated and

resettled with duecompensation and

recognition for theirsacrifice

12

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 stepsto 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 stillto be built to store water andmake it available during thenext century on a world widebasis, especially in the non-

industrialised countries

1313

ICID's Position

14

Effectiveness of dams for development

Large or small dams, if built without adequate preparatorywork, can fail to deliver expected results. Any dam couldthus prove less effective than planned. It is thereforenecessary to select cases of success or failure of bothlarge and small dams. Lessons are to be drawn fromfailures to guide future action. The owners of such damshave to be approached first for their assessments. If anew dam is identified, a bench-mark status if not availableat the time of construction, might have to be ascertainedto realistically assess its effectiveness. Where muchdepends on how the delivery system is operated, thedam is hardly the reason for any loss of efficiency.Greater attention is necessary in the irrigation sector tobring about and maintain perfection in the deliverysystems.

Storages of various magnitudes are a requirement forpractically whole of the developing world and dams ofvarious sizes fulfill that necessity. It is therefore,imperative that such a development process is supportedby effective procedures to minimise negative effects, ifany, and enhance benefits. Large dams contributesignificantly to the productive efficiency of irrigation, inaddition to giving ancillary and intangible benefits. Thelarge dams built in the past have provided water suppliesto needy areas for growing food, for drinking water, forreducing flooding, and for generation of hydropower atlowest of costs from amongst various options. Smallera dam, more is the cost per unit of water stored, butevery size has its role in development of basin resources.They are complementary to each other. They cannotreplace each other.

Assessment of options and decision makingframework

Sustainability

Sustainability has become the touch-stone fordevelopment effort since Agenda 21 was adopted at theRio Conference in 1992. Although its definition has haddifferent connotations for various development sectors,it means that fruits of development ought to be of

The IWRDM has to addressthe needs of the ultimate

stable size of globalpopulation.

Appropriate policies andguidelines on sustainabilityaspects of dams need to befully developed, and wheredeveloped they need to be

uniformly applied.

1515

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-ordinateddevelopment 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 lifelike 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 basinitself, 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.

16

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, whichcannot 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 agricultureremains 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 basinwith 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 largedams, 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 basindevelopment are notalternatives, but are

complementary to each otherto increase food productivity

of cropped land and toensure food security in

irrigable and rainfed lands.

1717

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 maximisingbenefits 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 supporttools for analysing and, iffavourable, implementingwater resources schemes

involving large dams, shouldbe developed, with due

regard to overall nationalinterests, individual basin

plans, safe designs and strictmonitoring.

The benefit cost (BC)analysis has to include socialbenefit- and cost streams toexpand it to Social Benefit

Cost Analysis (SBCA).

18

expensive facility may have to be put in place to meetthe needs of society. Water resources developmentand utilisation in most of the developing countries is ofutmost importance for their socio-economic upliftment,poverty alleviation programs and food security. Asovereign country no doubt will preserve its basic rightof deciding its own priority of developmental needs andmost suited options. Global criteria can at best indicateguidelines.

Environmental issues

Compensatory packages

Every human activity modifies the environment. Somechanges are for the good, some are not, but theawareness in the society about size and scope of theadverse impacts plays an increasing role in decisionmaking. Effort is made to mitigate and compensatesuch effects while increasing the positive impacts, sothat sustainability of development is maintained and thenatural resource base is not eroded. The challenge is toensure that the positive effects on environment outweighnegative effects. Mitigation/enhancement measureshave been evolved, over a period of time, by concernedprofessionals. ICOLD and ICID have prescribed detailedlistings, criteria and guidelines for study of environmentalimpacts and their mitigation. Many countries havedeveloped appropriate policies and measures forcompensating negative impacts. While respecting theprivilege of countries/governments to develop their waterresources plans and priorities, it will be only fair toexpect that adequate compensatory packages areprovided by them to the adversely affected people andto ensure that such people are better off after the projectimplementation than before it.

Adverse impacts with and without a dam

In the developing world, land and water development isrequired to take care of the population pressures andthe poverty level of societies. As development reducesthe poverty level and improves the standard of livingmainly by providing employment generation, this initself has positive effects. While adverse impacts of adam can be taken care of, the availability of freshwater

A sovereign country no doubtwill preserve its basic right ofdeciding its own priority ofdevelopmental needs and

most suited options. Globalcriteria can at best indicate

guidelines.

ICOLD and ICID haveprescribed detailed listings,criteria and guidelines for

study of environmentalimpacts and their mitigation.

1919

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 ofconstructing 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 ofenvironmental 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 checklistencourages the authorities to

embark upon studies toassess likely impacts on each

of the identified aspectsqualitatively andquantitatively.

20

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 ofstandards 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 tosuit 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 affecteddue 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 afterconstruction 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 generalguidelines could be

internationalised, much ofthe standardisation work has

to be done by a particularcountry within the country tosuit its prevailing conditionswith due regard to the safetyrequirements and mandatory

procedures.

2121

Large dam projects provide conducive environmentsfor livelihood enhancement, sharing of benefits andempowerment of weaker sections, especially womenfarmers. But in each sector for which withdrawals aremade, ICID encourages incorporation of the principlesof equity, efficiency, and economy amongst water users.Participation of dam affected people, alongwith dambenefited people, is important according to ICID forplanning of dam schemes and their size, coverage andarea of influence.

As a conclusion, ICID stresses that dams have playedand will continue to play an important role in thedevelopment of water resources, especially in developingcountries. In order to develop and operate successfulprojects, a balance has to be struck between therequirements based on the needs of society, acceptableside effects and a sustainable environment.