How can the concept of watershed be used to improve water quality?
The watershed concept is very important. It enables us to think in terms of water and land uses that are contained within a finite area of land. The watershed consists of surface water– lakes, streams, reservoirs, and wetlands– and all the underlying ground water. Only rainwater that falls within the watershed will affect the water quality in waterbodies within that watershed. Land uses are the sources of specific types of pollutants. If you identify and measure those same pollutants within your watershed, then there are a finite number of land uses that can be the sources of those pollutants. In addition, since watersheds have only one outlet that all of the smaller streams drain to, then this becomes a strategic place where the watershed can be monitored and characterized.