The clouds become so saturated with water that gravity literally pulls the water out of the clouds to the ground. Rain, snow or hail may fall, depending on the temperature of the surrounding air. Runoff Excessive rain or snowmelt can produce overland flow to creeks, rivers, ponds and ditches. Runoff is the visible flow of water in rivers, creeks and lakes as water stored in the drainage basin drains downhill towards the oceans. Percolation Some of the precipitation and snowmelt moves downwards, percolating or slipping through cracks and holes in the soil and bedrock until it reaches the water table, where it becomes groundwater.
Percolation is similar to water going through ground coffee and a filter.
Groundwater Subterranean or underground water is held in cracks in the rock and in pores or spaces in the soil. Depending on the local geology, groundwater can flow to support streams and ponds. It can also be tapped by wells, for drinking water. Some groundwater is very old and may have been there for thousands of years. The water table is the level to which water will rise, usually seen in a well.