Runoff from landscape irrigation, and organic wastes from leaking sewage pipes or septic systems results in excessive algal growth. When algae dies and is decomposed by bacteria, bacteria consumes great amounts of oxygen. Cutting or removal of riparian vegetation, particularly tree tops and shrubs that shade and cool the creek, leads to an increase in water temperature. Uprooting plants also causes water temperature to increase, but in addition allows bare soil to slough off into the creek contributing increased amounts of suspended solids. If creek water is too acidic or too basic, biochemical processes may be disrupted harming or killing plants and animals.
Human activities influence the pH of our creeks.
Air pollution from acid rain is a good example of what can happen when creeks become too acidic. As pH increases, smaller amounts of ammonia are needed to reach toxic levels for fish. As pH decreases, the concentration of metals may increase. Higher acidity increases their ability to be dissolved from sediments. In addition to the five parameters already discussed, schools measured water depth.