Monday, 31 December 2012

A strategy for Dam Construction. By : Jamal Fuad,Ph.D.*

 

If oil has been the main cause of conflict in the 20th century, water will become the main cause of conflict in the 21st century. Current water resources will come under pressure as global warming increases temperatures and rainfall decreases. At the same time the world’s population is constantly increasing and is estimated to reach 9 billion by 2030. This rise in the human population results in increased demands for water for domestic use, for food production and industrial demands.

The need for developing more water resources is worldwide however here we will consider the situation in Iraq, and Kurdistan in particular, to emphasize the need for a strategy to increase water supply and ensure efficient use of available resources. At the same time we must protect agricultural land, especially in Iraqi Kurdistan, where fertile lands are being steadily exhausted. Policies regarding land usage that were set up by the Ba’athist regime and current land usage activities in the region must be reviewed and amended. Under the Ba’athist regime fertile agricultural land was lost in the construction of towns to which they forcibly moved people, while the current policy of local government is inadequate and scarce, fertile agricultural land continues to be used for developments that could be situated on the less fertile mountain slopes or land that had been previously used for building.

The Logic of Building Dams

The construction of dams is carried out to form reservoirs of water for human consumption, industrial and agricultural use and also to prevent flooding downstream, increase ground water levels. At the same time construction of a dam and the lake formed behind it can improve the environment, increasing wildlife and the aesthetic aspects of the region leading to increased tourist attraction. An important use of dams is for the generation of electricity that environmentally friendly and relatively cheap. Construction of dams for this purpose is of particular importance where the topography is suitable and there is minimal loss.

In Iraqi Kurdistan, cereal crops and winter legumes are mostly grown under rainfed conditions, while summer crops are only grown where irrigation water is available. When rainfall is insufficient, winter crops also require supplementary irrigation to insure reasonable yields. Utilisation of irrigation will improve crop yields but any irrigation system must include in its plan a means of supplying required supplementary irrigation when needed.

Existing Dams in Kurdistan

There are two major dams in Kurdistan, the Dukan and Derbendikhan Dams. The first, completed in 1956, resulted in the loss of 270 square kilometers of the best agricultural land in Kurdistan, while the lake formed behind Derbendikhan dam, constructed in 1962, covers an area of 211 square kilometers and also resulted in the loss of high quality agricultural land. Both dams are designed to control seasonal floods, ensure irrigation water downstream, and to generate electricity. The Dukan dam powers 5 generators producing 400MW of electricity while the Derbendikhan dam powers 3 generators and produces 112 MW of electricity.

Other Considerations for Dams

Iraq is known for its large oil resources rich and cheap source of fossil energy which economically is more justifiable for use as energy source than water. In addition there is scope for renewable energy production using both solar and wind power. Therefore the decision to building any new dams should be based mainly on water requirements for human population and agriculture. Increasing the levels of water available for irrigation while minimizing the loss of agricultural lands to the development is important and we must ensure a net gain of irrigated land, thus increasing the production capability of the region.

Besides attention to the net gain of agricultural lands, there are other considerations that should be taken into accounts, as follows:

·       Will the proposed dam increase underground water?

·       Will the dam ensure safe drinking water?

·       Will constructing the dam separate linked communities and disrupt social contacts in the area?

·       How much rangeland will be affected by the development; whether it would detrimentally affect existing livestock that in the area?

·       Will the lake formed affect forest trees or restrict growth of fruit trees?

·       Will the proposed dam affect the environment and wildlife?

·       Will the proposed dam enhance tourism in the area?

Increasing the Efficiency of Irrigation

Current methods of the use of irrigation water are very wasteful. The use of furrow or basin irrigation as practiced by our farmers has lead to the deterioration of land on many farms because erosion, salt accumulation, and removal the top soil. Poor irrigation because fields were uneven reduced crop yields because of insufficient water of the high ground, while the lower levels are flooded. There is a vital need for more modern irrigation practices where water usage is minimized and water distribution is more even so ensuring adequate water for the growing crops.

The new irrigation technologies of sprinkler and drip irrigation should, in the main, replace the current furrow or basin irrigation. Where the latter irrigation methods are used it is important that the fields are even, the main irrigation canals remain intact, while a siphon is used to transfer water from the canals into the furrows in order to avoid destroying the integrity of the main canals. Using the siphon method decreases soil erosion and ensures the integrity of the main canals, thus avoiding the destruction of the existing furrows or basin borders.

In the case of a dam proposal where the basic justification for the dam was to increase irrigated lands downstream, far away from the location where the proposed dams were to be constructed then the basic justification ignored local gains and was therefore unbalanced. I suggest that in the case of a proposal that has been agreed but construction has not commenced immediate action is taken to send a team of experts to visit the proposed site and review the proposal in line with the new policies that have been advanced above. The team would present a detailed report that either supported the construction of the dam or proposed an alternative.

In summary I suggest a strategy based on the following principles:

        That energy production should only be looked at as a bi-product of a dam, not the main reason for which the dam is to be constructed. Energy production should be based mainly on fossil fuel.

        Ensure a net gain of agricultural lands in areas close to the sites where the dam is to be constructed;

        Minimize as much as possible the flooding of agricultural lands;

        The proposed dam should not negatively affect the social or the economic status of the region;

        Other considerations would include the degree of underground water replenishment in the region, increasing the supply of household water in the vicinity of the dam, and the possibility of enhancing tourism in the area.

        The economic appraisal should include all above factors to fully justify constructing the dam.

        To ensure application of adequate technology for use of irrigation water, it is essential that agricultural extension puts as its priority educating farmers on irrigation methodology including training in the use of sprinkler and/or drip methodology to avoid excessive water use, decrease erosion and soil salinity.

*Senior Agronomist, Internationl Consultant
Former FAO and WORLD BANK staff

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