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DRAFT <br />respectively. Average summer values for total phosphorus and TSS in Lake Orono, based on <br />five summer samples collected as part of this study, were 0.171 mg/l and 27 mg/1 respectively. <br />Based on total phosphorus data Lake Orono is classified as hypereutrophic. Poor water quality in <br />Lake Orono is largely due to a very high watershed drainage area to lake volume ratio resulting <br />in average residence times of only three days. Total phosphorus removal efficiencies within <br />Lake Orono were calculated to be less than 10 percent. This is much lower than lakes with <br />longer residence times where removal efficiencies can be on the order of 90 percent. <br /> <br />2. Fecal Coliform and Fecal Streptococci <br /> <br />The City of Elk River collected fecal coliform samples at the Lake Orono City Beach during six <br />sampling events in July - August 1997. Results indicated fecal coliform concentrations between <br />800 and 4,600 organisms/100 milliliters (ml), significantly above the National Public Health <br />Association Guideline of 200 organisms/100 ml (see Table 3). Additional sampling was <br />conducted on August 19, 1997 at various locations along the Elk River and at the Lake Orono <br />City Beach. Results indicate very high concentrations of fecal coliform and streptococci bacteria <br />for an inflow to Elk Rivef at Wapiti Campground and an inflow to Lake Orono from a <br />subdivision sedimentation pond with adjacent lands containing recently spread manure. The <br />concentration of fecal coliforms at the Lake Orono Beach was 70 organisms/100 ml. <br /> <br />By monitoring both fecal coliform (FC) and fecal streptococci (FS) concentrations and <br />evaluating the ratio of FC/FS, information regarding the origin of the fecal contamination can be <br />obtained. The FC/FS ratio for domestic animals is less than 1.0, whereas the ratio for human <br />beings is more than 4.0 (Wastewater Engineering Treatment/Disposal/Reuse, Metcalf and Eddy, <br />Inc., 1979). The data show low FC/FS ratios indicating fecal material from non-human sources. <br /> <br />FC/FS ratios from "Lake Orono City Beach" and "Inflow to Lake Orono from Subdivision" are <br />1.17 and _ 2.86 respectively. This could indicate a differential die-off of indicator organisms <br /> <br />N:\O$ 98\01XELKRI VER.RPT-db ] 5 <br /> <br /> <br />