GEOLOGY

Detailed explanation-1: -Tightly-packed particles such as clay and silt are not very permeable. In this case, the water cannot flow down quickly into the soil. Therefore, a heavy rainstorm is likely to cause runoff.

Detailed explanation-2: -If precipitation is greater than infiltration capacity, surface runoff occurs. If precipitation is less than the infiltration capacity, all moisture is absorbed. When a soil has been saturated by water then allowed to drain by gravity, the soil is said to be holding its field capacity of water.

Detailed explanation-3: -This more commonly occurs in arid and semi-arid regions, where rainfall intensities are high and the soil infiltration capacity is reduced because of surface sealing, or in urban areas where pavements prevent water from infiltrating.

Detailed explanation-4: -Surface runoff rainwater harvesting is a method of collecting rainwater flowing along the ground during the rains will be collected to a tank below the surface of the ground for irrigation and other purposes.