Surface Hydrology
Surface hydrology studies the relationship between water (from precipitation) and the runoff. The study of surface water hydrology is vital because the quality of runoff water can affect drinking water sources and the relationship between rainfall and runoff can help predict and prevent the occurrence of floods. The flow or discharge of rivers, streams, lakes, ponds, etc. is measured, as well as water levels in wells. Surface hydrologists also study the relationship between surface and groundwater.