Water quality is a reflection of land use in the surrounding watershed, pollution sources, instream and upstream activity, soils, temperature, plant life, geomorphology, climate, and amounts of precipitation. Water is amazing - the only substance on earth that naturally has all three states of liquid, solid and gas. Its properties allow it to dissolve more elements and substances than any other liquid. It is the most abundant compound on earth, yet less than 1% is available and safe for drinking. Monitoring our local streams and waterways takes many forms, and many different agencies and volunteer groups help to assess and protect water quality.
Water quality of streams in urban areas is often severely degraded due to stormwater runoff from impervious surfaces like roads, parking lots, roofs and compacted ground. Agricultural runoff, use of fertilizers and pesticides, litter and illegal dumping or draining of chemicals, oil, trash and wash water into storm drains add more pollutants.
The amount of impervious surface in a watershed can be a factor in water quality. The Watershed Assessment Model for North Carolina (example watershed is Little Creek) helps state and local planners to evaluate the risk of water quality degradation in the State's waterways.