In the fall semester of 2009, 16 students from Geosciences and Environmental Studies at Western Michigan University enrolled in Environmental Field Geochemistry and completed a water quality assessment of Woods Lakes.

 

The results of this study demonstrate that the deepest part of the lake remains anoxic, with no detectable oxygen at depths below 9.5 m, as late as the last sampling date in fall (November 21, 2009). At depths below 8 m, DO drops dramatically, pH decreases and the concentrations of dissolved iron, manganese, ammonium and sulfate all point to significant degradation of organic matter via anaerobic pathways and persistent eutrophic conditions in the lake. Furthermore, conductivity and chloride increase to levels that exceed the chronic toxicity threshold for freshwater aquatic organisms.

 

Data from the retention pond also demonstrates very high levels of chloride, consistent with significant runoff and retention of chloride from road salt in the surrounding watershed. Woods Lake should be carefully monitored to assess the sources and impact of increasing accumulation of roadsalt runoff, as this may dramatically impact lake dynamics.

 

Reduction of phosphate use in the watershed (detergents and especially fertilizers), proper disposal of leaves and lawn clippings and reduction of suspended solid input into the lake may help to slow eutrophication, but will have little impact on roadsalt related changes to the lake chemistry and biology.