The reason why the dam is narrow on the top and wide on the bottom

The reasons why the dam is narrow at the top and wide at the bottom are as follows:

The reason is that, under the same other conditions, the pressure of liquid increases with the increase of depth, so the lower part of the dam will bear more pressure than the upper part, so the lower part is wider than the upper part.

Mainly according to the mechanical principle, the firmness and long-term nature of intercepting water source impact are enhanced. The riverbank with wide top and narrow bottom can block different pressures, save materials, prevent sediment from slipping, reduce its own pressure, and make the riverbank more solid.

The role of the dam:

Dam is a kind of water retaining structure, which intercepts the water flow in the river to raise the water level or adjust the flow. It can form reservoirs, raise water levels, regulate runoff and concentrate water heads, and can be used for flood control, water supply, irrigation, hydropower generation and improvement of navigation. River training structure, which adjusts the river regime and protects the riverbed, is also called a dam, such as groins, shun dams and submerged dams.

Disadvantages of the dam:

Leading to the depletion of fish resources. Dams can not only intercept rivers to reflect the recharge effect of water storage, but also block the way of various aquatic organisms, making it impossible for fish to breed smoothly.

Destroyed the distribution of water resources. The completion of every dam means that the water flow in some places is blocked. In the Bolan area of West Orissa, India, there used to be dozens of ponds in almost every village. However, after the completion of the dam, 80% of the ponds disappeared, which directly reduced the local grain output.