A spillway is a divergent water pathway controlling the release of water from a reservoir into a downstream area of a river. Water flows over a spillway during flood periods—when the reservoir cannot hold excess water.Wikipedia
Total Daily Maximum Load, or TMDL, is the calculation of the maximum amount of a pollutant allowed to enter a waterbody so that the waterbody will meet and continue to meet water quality standards for that particular pollutant.US Environmental Protection Agency (EPA)
A watershed is a land area that channels rainfall and snowmelt to creeks, streams, and rivers, eventually outflowing to reservoirs, bays, and the ocean.
Water conservation includes all the policies, strategies, and activities to sustainably manage the natural resource of fresh water, to protect the hydrosphere, and to meet current and future human demand.Wikipedia