AWRI Environmental Chemistry
Preliminary Watershed Assessment: Deer Creek Watershed
The Deer Creek watershed, located in Ottawa and Muskegon Counties in west Michigan, is relatively small in area (~ 9,050 ha or 22,362 acres), yet faces a number of severe environmental problems. An assessment of nutrient loading was conducted to provide preliminary information to assess the magnitude of the problem and identify critical areas for remediation and/or additional investigations. The assessment included the following elements:
- An inventory of current land cover and land use
- Water quality analyses at selected locations in the watershed for temperature, major nutrients, E. coli, and stream discharge
- Development of nutrient and suspended sediment loading estimates related to the sampling sites and their respective drainage areas
- Identification of key issues and areas of concern in the Deer Creek watershed
The GIS analysis revealed that agricultural land use dominated the landscape (85%) followed by forest (8%), wetland (3%), and urban (3%). Riparian zones exist, but they have been modified and no longer protect the adjacent habitat. Consequently, the hydrology and water quality of Deer Creek were impacted by agricultural nonpoint source pollution. Although the watershed has a highly modified land cover, the temperature regime of Deer Creek is still capable of supporting a cool water fishery.
High concentrations of suspended sediment, nutrients and E. coli were found at all eight locations that spanned the course of the main branch of Deer Creek. Total phosphorus concentrations were above levels recommended by the EPA to prevent eutrophication. Stream discharge and nutrient loadings also were examined. In the limited sampling conducted, a 30-fold difference between stream discharge at base flow and high flow was noted. These conditions indicate unstable hydrology that responds dramatically to rain events. Unstable hydrology coupled with agricultural land use and limited natural cover in riparian zones have resulted in a stream that was highly impacted by erosion and sedimentation. Adverse hydrological conditions also promote the excessive loading of nutrients in Deer Creek. Two major problem areas were identified with respect to nutrient loads:
The development of a comprehensive watershed management plan that addresses the above issues in conjunction with a basin wide strategy to limit runoff by stabilizing hydrology through BMPs is essential for the restoration of water quality in Deer Creek.
Page last modified January 20, 2010