Because water pressure is more intense at depth than it is near the surface - hence the dam has to be stronger at the bottom - it withstands more pressure at the bottom.
to hold the water better but at the top it's thinner to get water in
i dunnobecause they are
The engineers.
they built dams to keep the flooding out of their cities
hydroelectric dams
The pressure of the water (the weight) is greater at the bottom, due to the depth of the water. As the pressure is less near the top, the top of the dam wall doesn't need to be as thick as the bottom of the dam wall.
Most large dams are built in the North, but small ones are mainly in the middle of pakistan.
dams
Yes there are many dams and more dams are being built. i dont know how many and i would like to know.
dames and barrages are built to store and redistribute water
Yangtze River in China has three Gorge Dams built. It is to keep the floods down and to keep the cities safe.
Dams are built to generate electric power, to create a body of water for irrigations of farms, for recreational uses, for erosion control (small dams), but in most cases decrease the area of farmland.