Monday 5 September 2011

A STRATEGY FOR DAM CONSTRUCTING--استراجية بناء السدود

By; Jamal Fuad, Ph.D., Senior Agronomist,
Former FAO and WORLD BANK staff, International Consultant

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 would come under pressure since weather trends points to warmer climate and decreased rainfall. Further, world population is on the rise, currently at quadruple the numbers that existed at the beginning of the last century. Likewise, livestock has also been on the increase, while agriculture itself has been intensified to increase outputs matching the rising trend of the population. Industries have likewise been expanding competing with the needs of other sectors. Additionally, as standard of living is improving, more demand is being on food items. These factors have negatively affected water availability downstream, while water shed area themselves been on the decline and facing deterioration through erosion, general abuse, and use as settlements and required infrastructure.

The need for developing more water resources is worldwide. However, I will specifically deal with the situation in Iraqi Kurdistan to emphasize the need for a strategy to increase water supply efficiency of water use.

I would like also to emphasize the need to protect agricultural lands, especially in Iraqi Kurdistan, where fertile lands are being steadily exhausted. Earlier Bathist policies and current land use activities in the region must be reviewed and amended. The Bathist regime has used many agriculturally fertile lands to construct collective towns, while the current policy of the local governments is inadequate and continues to add to the ongoing dilemma of abusing the scarce fertile agricultural lands, instead of utilizing agriculturally unfit mountain slopes.

The Logic of Building Dams
Dams are being built mainly to insure water for irrigation, when rainfall is insufficient or completely lacking. In Iraqi Kurdistan, cereal crops and winter legumes are being 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. Therefore, any irrigation system should include in its plan means of supplying required supplementary irrigation when needed.

Dams are also built to stop flooding downstream, to increase ground water supply, to improve the environment and to add esthetic qualities to a region for possible use of tourism.

An important use of dams is for the generation of electricity, an environmentally friendly and relatively cheap source of energy. This use is of particular importance where topography is suitable and loss of agricultural lands is minimum.

Existing Dams in Kurdistan
There are two major dams in Kurdistan, Dukan and Derbendikhan Dams. The first one, completed in 1956, has inundated 270 square kilometers of the best agricultural land, while the second, constructed in 1962, covers an area of 211 square kilometers of similarly high quality agricultural land. Both dams are designed to control seasonal floods, insure irrigation water downstream, and to generate electricity. Dukan Dam runs 5 generators, producing 400MW of electricity while the second, Derbendikhan Dam, runs 3 generators, producing 112 MW of electricity.

Use of Agricultural Lands Against Energy Generation: Is It Justifiable?
Iraq is known for its rich and cheap source of fossil energy which economically is more justifiable for use as energy source. Therefore decision of building a dam should be based mainly for increasing irrigation capacity, minimizing at the same time loss of agricultural lands due to required storage capacity of the dams. It is important that we insure a net gain of irrigated land, increasing thus the production capability of the region.

Other Considerations for Dams
Besides attention to the net gain of agricultural lands, there are other considerations that should be taken into accounts, as follows:
• Would constructing a dam separates linked communities and disrupt social contacts in the area?
• How much rangelands would be affected; whether it would affect existing livestock that use the area?
• Would the inundated area affects forest trees or restricts growth of fruit trees?
• Would the proposed dam affect the environment, the wild life?
• Would the proposed dam enhance tourism in the area?
• Would the proposed dam increase underground water?
• Would the dam insure safe drinking water for the area residents?

Increasing the Efficiency of irrigation water
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 many farm lands due to resulting erosion, salt accumulation, and removal the top soil. Uneven irrigation due to uneven fields has reduced crop yields due to insufficient water at the high points, while the lower points are inundated. There is a need to more modern irrigation practices where water use is minimized, while water distribution is more even, insuring adequate water for the growing cops.

The new irrigation technologies of sprinkler and drip irrigation should replace, for the most part, 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, unbroken, using a siphon to transfer water from the canals into the furrows, in order to avoid destroying the integrity of the main canals. Using siphon method decreases soil erosion and insures the integrity of the main canals, avoiding thus the destruction of the existing furrows or basin borders. In this connection I find the following strategy appropriate:

The basic justifications was for increasing irrigated lands downstream, far away from the location where the proposed dams were to be constructed. The basic justification ignored local gains and therefore is unbalanced.

For dams proposed but mot yet constructed, I suggest that a team of expertise visits the proposed sites and reviews earlier proposals for specific dams in line of new policies that have been advanced above. On its return the team would present detailed new proposals, either supporting the construction of such dams, or otherwise propose alternatives. As a 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.
• Insure a net gain of agricultural lands in areas close to the sites where the dam is to be constructed;
• Minimize as much as possible inundating agricultural lands;
• The proposed dam should not negatively affect the social or the economic status of the region;
• Other considerations would be in the degree of underground water replenishment in the region, increasing the supply of household water in the vicinity of the dam, and possibility of enhancement of tourism in the area.
• The economic appraisal should include all above factors to fully justify constructing a dam.
• With regards of irrigation methodology, emphasis should be placed on the use of sprinkler and/or drip irrigation. When furrow or basin irrigation methodology is used, it is important that fields are made even for even water distribution, using at the same time the siphon method for transferring water from the irrigation ditch into the furrows or the basins to avoid soil erosion or destruction of the furrow or basin borders.
• To insure application of adequate technology for use of the irrigation water, it is essential that agricultural extension puts as its priority educating farmers on irrigation methodology to avoid excessive water use, decrease erosion and soil salinity.

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