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January 26, 2024 <br />Don Peterson <br />Page 10 of 21 <br />Reference: Water Quality Assessment of Silver View Pond, Mounds View, MN <br />Silver View Pond <br />� Upper 5 cm 25th Percentile Median 75th Percentile <br />0.50 <br />0.45 <br />0.40 <br />a� 0.35 <br />E 0.30 <br />a 0.25 <br />x <br />0.20 <br />m <br />W 0.15 <br />0.10 <br />0.05 <br />M <br />Sampling Station <br />Figure 4. Concentrations of redox-sensitive phosphorus in the upper 0-5 cm of sediments collected <br />from Silver View Pond. <br />Phosphorus Budget <br />A major objective of the water quality diagnostic assessment includes development of a phosphorus mass <br />balance model for Silver View Pond that estimates the proportion of phosphorus loads from the watershed <br />drainage area and from internal sediment release. Determination of the relative magnitude of external <br />versus internal phosphorus loading serves to inform management strategies to reduce phosphorus <br />concentrations in Silver View Pond. To accomplish this objective, Stantec developed a P8 model (described <br />in more detail below) to simulate phosphorus loads to Silver View Pond from the surrounding drainage <br />area. The loads from P8 were input into a lake response mass balance models to determine the relative <br />proportion of external versus internal phosphorus loading. <br />Internal load estimates were based on the direct measurements of phosphorus release rates under oxic <br />and anoxic conditions (in units of mg/m2-d). Extrapolation up to whole -lake loads requires an estimate of the <br />areal extent of anoxic and oxic conditions, which can be estimated for polymictic small shallow lakes based <br />on an anoxic factor (AF) model developed by Gertrud Nurnberg5. <br />5 Nurnberg, Gertrud. 2009. Accessing internal phosphorus load — problems to be solved. Lake and Reservoir <br />Management 25(4): 419-432. <br />Design with community in mind <br />