The correct options are
C The silt collected from the tanks after silting can be used to grow crops.
D Desilting helps in enhancing the water holding capacity of the tank.
Desilting is a process by which the naturally accumulated silt is removed from the tank. This increases the tank's water holding capacity. Desilting also provides us with the accumulated silt that can be used in the agricultural fields, owing to the rich minerals present in it. Desilting helps in enhancing the water holding capacity of the tank.