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Technical Findings <br />Since monitoring information for Bennett was available from Ramsey County, Bennett was <br />visited only once on July 18, 2001 as part of the Natural Resources Inventory. <br />Water Quality <br />Water quality data for Bennett Lake extends as far back as 1984. Data collected between May <br />and September of 2001 by Ramsey County staff is presented in Appendix A, Table 2 and shows <br />that the mean secchi depth was 1.11 feet, a relatively low reading even for an urban lake in this <br />region. The growing season mean concentration of total phosphorus for Bennett was 140 ug /1, <br />putting it toward the poorer quality end of the D category (69 -152 ug /1) for the lake water quality <br />report card developed by the Met Council. These data indicate that Bennett Lake is hyper - <br />eutrophic, meaning it is very nutrient enriched and can be expected to show problems with <br />severe algal blooms for most of the recreational season. <br />Aquatic Vegetation Survey <br />A one -time reconnaissance level survey of aquatic vegetation in Bennett Lake was carried out on <br />July 18, 2001 as part of this project. Following are the conclusions of the survey: <br />• There was evidence of a curly -leaf pondweed infestation in the lake but no <br />evidence of eurasian milfoil. The survey was conducted well after the peak growth of <br />curly -leaf pondweed usually occurs, so this exotic might be much more dominant <br />earlier in the summer. <br />• The maximum depth of submergent aquatic weed growth at the time of the <br />survey appeared to be about 3-4 feet. This is likely a reflection of the limited light <br />penetration through the water column caused by algal blooms growing in response to <br />high nutrient concentrations in the lake. <br />• The diversity of native macrophyte species observed was low, with only <br />coontail and Canadian waterweed observed in any abundance. <br />• There were significant growths of filamentous algae floating in mats on top of <br />the water in many inshore locations. This is symptomatic of a very nutrient enriched <br />system. <br />City of Roseville 51 <br />Parks Natural Resource Management <br />