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January 26, 2024 Don Peterson Page 2 of 21 Reference: Water Quality Assessment of Silver View Pond, Mounds View, MN Aquatic Vegetation To assess the presence, abundance, and health of the lake's aquatic vegetation community, Stantec surveyed the aquatic plant communities in Silver View Pond on 6/27/2023 and 6/28/2023 (early season) and on 8/31/2023 (late season). Each lake was surveyed at distinct locations across a grid using the point - intercept methods described in Madsen (1999).' During each point -intercept survey, all submerged, floating leaf, and emergent species were identified at each survey point. Surveys were conducted at two periods in the summer growing season to account for different life cycles of commonly found aquatic native and invasive species in Minnesota. At each survey location a double -sided, weighted 14-tine rake was thrown from the boat, allowed to sink, and pulled across the lake bottom to represent approximately 1 square meter of lake area. We refer to this process as a rake toss. For each rake toss, vegetation was removed from the rake and identified to the species level. Sediment Chemistry Sediment cores were collected on 9/6/2023 from three locations in Silver View Pond, as shown in Figure 1. Sediment cores were collected for two purposes. The first was for laboratory incubation to quantify sediment phosphorus release rates under oxic and anoxic conditions. Sediments were incubated at UW- Stout under temperature- and light -controlled conditions. The second analysis was for phosphorus fractionation to quantify the mobile and non -mobile pools of phosphorus. Each core was sectioned into two depth intervals (0-5 and 5-10 cm depth intervals) for phosphorus fractionation analysis (Table 1) and sediment characteristics (i.e., moisture content, bulk density, and percent organic matter). The purpose of this analysis was to quantify the pools of P that are subject to diffusion from the sediments and characterize the areal extent of potential internal P loads to determine the feasibility of an alum treatment to suppress internal P loads. ' Madsen, J.D. 1999. Point intercept and line intercept methods for aquatic plant management. APCRT Technical Notes Collection. U.S. Army Engineer Research and Development Center, Vicksburg, MS Design with community in mind