Erosion and Sedimentation
Sediments increase water turbidity which is a key indication of water quality. High turbidity indicates poor water quality in lentic environments. In some cases however, sedimentation is essential for bed deposition. Bed deposition is responsible for the renewal of deltas and the transportation of nutrients to downstream communities in lotic environments.
Sediments can be expected from:
- Erosion leads to sedimentation
- Sedimentation increases water turbidity
- Turbidity decreases water quality
- light inhibition
- traps excess nutrients
Sediments can be expected from:
- Flooded agricultural lands
- Drawback zones. Defined as periodically flooded zones, these areas are unable to support lasting vegetation which leads to an increase in erosion consequently, sedimentation.
- Midyat limestone fragmentation. This limestone, which forms the banks and reservoir, is stratified with weak clays. During high reservoir levels periods the weak clays are expected to saturate and during low levels, they will dessicate. These fluctuations will lead to the fragmentation of the rock and provoke rock falls and more particles to end up in the reservoir water.
Implications
The physical diversion of tributaries will lead to increased erosion and thus sedimentation which will remain trapped in the reservoir. The natural process of stratification will mean that the downstream water will be cooler leading to a loss of nutrients and dissolved oxygen which can be detrimental to biota and inhibits bed deposition. Downstream marshes rely on sediments to replenish losses to sea and provide nutrients for its inhabiting flora and fauna.
Moreover the excess sediments will remain trapped in the reservoir causing the reservoir's depth to decrease over a period of time if not removed.
Moreover the excess sediments will remain trapped in the reservoir causing the reservoir's depth to decrease over a period of time if not removed.