Can the Big Bayou be saved? Water quality assessment and management recommendations for Spring Lake Watershed, Ottawa and Muskegon counties, Michigan

Spring Lake is a 525-hectare river-mouth lake, lying in a subwatershed of the much larger Grand River Watershed. Appreciated as a resource for recreation, irrigation, and business uses, the scenic eutrophic lake has been plagued during the past several summers with large algal blooms of Microcystis and dense mats of Ceratophyllum and Rhizoclonium. Through a resident survey, 62% of the respondents found the water quality of the lake as unacceptable. Seasonal water and phosphorus budgets completed in this study suggest that the tributaries, septic systems, and lawn fertilizer runoff were the largest external phosphorus loadings, respectively contributing 44%, 28%, and 23% of the total phosphorus inputs from October to April. From May to September, the largest loadings were again from septic systems (86%) and tributaries (10%). In order to reduce the nuisance algal blooms and rootless aquatic plants, lake nutrient concentrations must be lowered by reducing all external nutrient loadings by implementing best management practices in the watershed to control non-point source runoff. Expanded public education in lake ecology will enhance stewardship for the lake ecosystem and aid in the reduction of nutrients. Because nitrogen may be co-limiting with phosphorus, the development of a nitrogen budget is also recommended.