DAMS

What is DAM ?– The arrangement made for systematic control

of water flow for better optimum utilization of available water.

– Humanity control over Natural resources

8000 years ago - Sumerians build irrigation based civilization (between Tigris and Euphrates rivers)

1ST CENTURY BC – Low height dams were built in Mediterranean middle east , central America, china

5th century AD – Srilankan dam 34 mt height was built (worlds highest during that time)

1832 – Development of turbine lead to hydropower, large dams

19-20 century – Hydro electric plants started operations in US , ITALY, NORWAY

DAMS-CIVILIZATION (HISTORY)

1930-Improvement in turbine technology started mega DAM boom

20-21 Century – Started dams to meet water demands 1930-1970 - Construction of large dams became usual

with economic progress 1970 – It reached peak (i.e - each day 2-3 new dams

commissioned in the world) North America and Europe became technically attractive

sites 45,000 – Large dams ( >15 mt height) 8,00,000 – Smaller Dams 2/3rd of Large dams are in China Asia, Europe, North America Constitutes for 95% of dams Africa very little no of dams

DAMS-CIVILIZATION (HISTORY)

Why DAMS (Reasons) 1.4 billion km3 of water is available in the world

( ice, water, water vapor) 97% of the above is sea water Conversion of available water to usable water Reducing variability in rivers flow w.r.t seasons Water storage & availability due to climatic

change Regulating water for different purposes Safety from social and economic tragedies SUSTAINABLE ENERGY GENERATION

Purpose of Dams 48 % of Dams – for irrigation contributes for large

quantities of food production 15% of Dams – Domestic & Industrial water 8% of Dams – Flood control 4% of Dams – Recreation +Inland navigation fish farming 20 % of Dams – Generates hydropower 40% dams in Europe are hydropower dams Most of the dams are multi purpose dams priorities may be

different- includes• IRRIGATION

• Flood control

• HYDROPOWER

• Domestic

• Industrial water supply

Purpose of Dams (India) 80% Rain happens during Monsoon ( 100 days span –45

rainy days) 60-80% Precipitation occurs in 6-8 intense rain spells We can use – Insitu

- Extending residence time (infiltration/ground water

recharge)

- Water shed MGMT

- Little check dams

- Small/ Medium irrigation works

Still large water is getting wasted

Benefits of Dams 40 % Of world food production comes

from Irrigated forming out of which 16% is contributed due to dams.

30-40% of 268 million hectares of irrigated land is watered from dams

19% of world energy comes from hydro-electric power ( which includes 150 countries)

– 90% of 24 countries

– 50% in 63 countries

Problems with Dams Most of large dams – unable to achieve technical, economic,,

social objectives, exhibited poor financial recovery costs. Impact on Ecosystem are more ‘- than ‘+’ in many cases (wild life,

species etc.) Serious consequences on population displacement, cultures etc. Loss of forests , wildlife habitat, the degradation of upstream

catchments Loss of aquatic biodiversity of up stream and down stream

fisheries, services of flood plains, wetlands and adjacent marine system

Cumulative impacts on water quality, natural flooding and species composition where no of dams on same river

Sedimentation and long tem loss of storage is a serious concern globally

Water logging and salinity effects .

The fragmentation and physical transformation of rivers.

Serious impacts on riverine ecosystems Social consequences of large dams due to the

displacement of people. Water-logging and salinization of the surrounding

lands. Dislodging animal populations,damaging their habitat

and cutting off their migratory routes Disruption of fishing and waterway traffic The emission of greenhouse gases from reservoirs due

to rotting vegetation and carbon inflows from the catchment is a recently identified impact.

Problems with Dams

SOCIOECONOMIC IMPACTS OF DAMS

Poorly managed involuntary displacement and loss of livelihood

Many displaced were not recognized and compensated

Depriving of indigenous people locally available resources not available

Chance of water borne diseases Inadequate distribution of project benefits

to affected communities

Displacement due to Dams Displacement by definition means involuntary Displacement is not a single event, but a series

of happenings, affecting human lives in many ways (years to decades gap)

For eg: Sradar sarovar dam Govt. it self encourages deforestation

Among affected communities, gender gaps have widened and women have frequently borne disproportionate share of the social costs and were often discriminated against in the sharing benefits

Ethical dilemma with dams Rights of a small no .of locally affected population

vs flights of large no. of potential beneficiaries Conservation of Natural resources in the context of

satisfaction of essential human needs by exploiting natural resources

Increased production of wealth to support growing needs vs fair distribution of accumulated wealth

If we are going to have sustainable development, we can not leave the environment and impacts on the environment should be minimized

There are more good dams than bad ones

CASE STUDY

NARMADA RIVER Dam

Three George Dam , china

Turkish Dam Controversy

Controversy on hydropower Dams also provide energy in the form of Hydroelectric

power Hydropower constitutes 13% in the US ( reduction in

200 million tons of CO2/Year) 99% in NORWAY,75% in New Zealand,70% in Latin

America,World wide 19 gigawatts electricity. Hydropower plants are unsustainable in countries where

frequent droughts cripples Historically , Planners of large dams have ignored

additional cost factors human resettlement costs, environmental consequences,capital costs, social costs (cost effectiveness ?)

Silatation can reduce dam capacity, diminishing poer capacity, depletion in d/s farm lands

Possible solutions to Improve the Acceptability of Dam projects

Public acceptance – key decision Avoid and minimize ecosystem impacts Engage in participatory, development

needs and options Affected people livelihood be improved Resolve past inequities and injustices Conduct regular and periodic review Recognition of rights and assessment of

risks, increase stake holders Corrupt practices should be avoided etc.