Liberty Creek is the main tributary to Liberty Lake, where it drains approximately 10 square miles of mountainous watershed area above the lake (Montgomery Consulting, 1990). The County Park encompasses approximately 3500 acres of this mountainous watershed. Through most of its length, the creek is a swift stream of very cold, high quality, nutrient poor water, and generally exceeds Washington State Water Quality Standards for Class AA (“extraordinary”) waters in all physical and chemical characteristics (Water Quality Criteria, Washington State Department of Ecology, 1982).
At the south end of the lake is a seasonal 155-acre wetland. In 1934, the Bureau of Reclamation constructed a bifurcation in Liberty Creek to assist and divert stream flow around the wetland and to stop annual flooding of the wetland from runoff. In conjunction with the bifurcation, the Bureau also constructed a wetland-lake dike to assist in draining and improving the marshland for agricultural and animal farming activities. Later in 1950, channel modifications were conducted in which the stream flowed in a manmade diked channel along the east edge of the wetland. In 1977, a diversion structure was installed on the creek at the bifurcation, and channel improvements and dike construction followed in 1979 (Kennedy, 1986).
A 6 inch PVC stilling well has been installed on Liberty Creek above the bifurcation and channel modifications. The purpose for the installation of this site is to monitor the continuous flow of Liberty Creek into the wetland and lake. This stilling well will offer real time data valuable for calculating discharge, plotting the stream hydrograph, and pin pointing runoff and storm events critical for nutrient sampling and loading. Ongoing monitoring will ensure quality data useful in calculating hydrologic and nutrient budgets while maintaining and establishing baselines and trends. A rating curve has been established for discharge at the site.