2000 Indicator Study

Turbidity is a measure of the clarity of water within a stream system. A high turbidity number indicates that the water is less clear, having more dissolved solids, whereas a low turbidity number indicates that the water has a greater clarity. Turbidity is caused by soil erosion, urban run-off associated with impervious surfaces, waste disposal, more bottom dwelling organisms, and algal blooms. Turbidity is an important measure in terms of stream quality because it affects numerous parameters in terms of the ecosystem. The presence of turbidity causes an increase in water temperature and lowers the amount of dissolved oxygen available. This combination can be detrimental to many organisms including salmon and other fish species. Thus it is important to measure turbidity. In addition, turbidity is easily measured using a Hach kit and easily understandable.

Turbidity ranges are currently under state regulations and in Clover Creek and its tributaries cannot exceed a value of 5 NTUs (WAC 1997). Data has been collected by the Department of Ecology and by the Environmental Methods course starting in 1994. By measuring turbidity, it will help a number of the stakeholders involved to determine whether or not the water quality is meeting their goals. For instance, Lakewood's Comprehensive Plan is "actively identifying and pursuing ideas opportunities to reestablish a balance between Lakewood's urban and natural systems and restore such natural spaces as creek channels…[to] help overcome past encroachment by development". (Clover Creek Watershed Goals 2000). Other stakeholders have similar interests and based on the data as represented over time, many of the sites during many seasons are in compliance with the state standards. More data from a wider time range and over many seasons would be helpful in determining long-term trends.