Common Factors for Dam Disasters:
Some common factors that can damage the dam’s structure include the scouring effect, pipeline, landslides, defective design of spillways, and lack of proper drainage management. These are discussed as follows.
Scoring
When the dam is allowed to release water from its reservoir, it results in enhanced stream velocity. As a result, small floods occur near the dam or reservoir. This leads to the scouring and armor of the river bed.
Most of the sudden flood power picks up small sediment such as silt, sand, and gravel, as well as water bodies and animals, leaf debris, and large tree debris. In addition, the sand is taken down.
Initially, the river, with negligible sediment load, has improved carrying capacity and takes up sediment from the stream bed below the dam. The nature of the rocks in the reservoir or near the dam controls the intensity of the scouring effect.
Piping
Internal erosion of soil particles within the dam is one of the most common causes of earth dams failure due to the water flowing through it. Internal erosion is especially dangerous because there is no external evidence or subtle evidence that it is happening. Internal erosion is manifested by the migration of clay particles by suction or piping.
Piping is triggered by the erosion of particles from the bottom and along the upstream line towards the outside environment until a continuous pipe is formed.
Aslo Watch:
Landslides
This is one of the most destructive reasons for the failure of any dam. Landslides at the top of the dam or inside the reservoir are dangerous because of instability in the center of the structure. In addition, this can lead to dam silt.
Therefore, it is necessary to have basin treatment in the upstream part of the dam in landslide-prone areas. This will save the life of the dam and protect it from damage.
Spillway’s defective design
The spillway is a structure used to provide a flow-controlled release to a dam or levee. Spillways release flooding so that water does not overflow and damage or destroy the dam.
Except for good periods, the water does not usually flow over the spillway. This cannot be over-emphasized and the site must be carefully inspected before a detailed plan for the construction of the dam. The design of spillways, if done with loose sediment or broken rocks, can pose hazards.
Lack of proper drainage management
Drainage is an important component of any reservoir or dam efficient function. Slope modifications are required on the upstream and downstream sides of the dam, reducing the speed of water to exert pressure on the dam wall. If drainage modification and its slope scale are not maintained, it will speed up the removal of silt.
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