COSUMNES RIVER PRESERVE WATER QUALITY AFFECTED BY SEASONAL FLOW MANAGEMENT

The Cosumnes Watershed is an important hydrological system in Northern California, not only because it has been relatively unchanged by humans, but also because it can be used to study watershed sustainability and water quality. Ecological areas of importance include habitats within the Cosumnes River Preserve. The Cosumnes River Preserve, located near the mouth of the Cosumnes River, covers about 50,000 acres of land. The preserve was created to permanently protect a variety of habitats and wildlife, including opportunities for people to experience the natural landscape. The management plan is designed with these aspects of the preserve in mind. The two main goals of the management plan are to restore and maintain native biological communities to sustain resident and migratory species and to improve the stewardship of the lands in the Cosumnes River Watershed. This plan includes water flow management and conservation in the wetlands that sustain migratory bird populations on the Pacific Flyway travelling south. The Pacific Flyway is an important north-south corridor of bird migration extending from Alaska to Patagonia. The Cosumnes River Preserve lies along this corridor and supports populations of migratory and non-migratory birds. As part of the flyway, the wetlands and riparian habitats in the preserve are a very important source of food and shelter. Over 250 different avian species visit the preserve each year.

We hypothesize that changes in water flow patterns between summer and winter operations impacts water quality. We measured water quality parameters such as conductivity, pH, dissolved oxygen, and temperature throughout the preserve, including all primary inlets and outlets to assess the winter mode water quality.

Continued study to establish the summer flow system water quality parameters will provide a foundation for establishing a link between water quality and management practices. It is very likely that the water quality, and therefore, the viability of the food chain supporting migratory birds, is closely coupled to discharge throughout the Cosumnes River Preserve. The water quality in the Cosumnes Preserve is vital, not only for the local wildlife, but also for future implications connected to the Sacramento-San Joaquin Delta, and for comparisons to other, highly managed watersheds.