Assessment Comments
Assessment is based on results of water quality, aquatic vegetation, and fish monitoring conducted by the IDNR shallow lakes and wetlands monitoring program from 2006 through 2008 and information from the IDNR Wildlife Bureau.
Basis for Assessment
SUMMARY: The Class B(LW) (aquatic life) uses are assessed (monitored) as "not supported" due to poor water transparency and high levels of chlorophyll a at this wetland.
EXPLANATION: Results of water quality, fish, and vegetation monitoring from the IDNR wetland monitoring program suggests that the Class B(LW) (aquatic life) uses are "not supported" due to poor water transparency and high levels of algae (chlorophyll a) at Dan Greene Slough. Using the median values from this survey from 2006 through 2008 (approximately 23 samples), Carlson's (1977) trophic state indices for Secchi depth, chlorophyll a, and total phosphorus were 76, 82, and 84, respectively for Dan Green Slough. According to Carlson (1977) the index values for Secchi depth, chlorophyll a, and total phosphorus all place Dan Green Slough in the hypereutrophic category. These values suggest extremely high levels of chlorophyll a and suspended algae in the water, extremely poor water transparency, and extremely high levels of phosphorus in the water column.
Additional monitoring of fish and aquatic vegetation populations at Dan Greene Slough suggest that the high levels of algae and turbidity have adverse effects on fish populations and limit the production of rooted aquatic vegetation in this wetland.
