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Section 4 - Reshanau Lake <br /> bottom waters are mixed readily with the entire water column. The surficial and bottom <br /> temperatures for Reshanau Lake are contained in Appendix B. Under different macrophyte <br /> conditions, Reshanau Lake would experience continual mixing. <br /> Dissolved Oxygen <br /> 1 Dissolved oxygen levels during the 1995 growing season showed oxygen levels at or above 5 mg/1 <br /> at the surface and 1 meter(Figure 4-5),but the DO level at the 2 meter interval periodically dropped <br /> Pe Y PPe <br /> below 4 mg/l particularly during the period of curly-leaved pondweed die off. A DO concentration <br /> of 5 mg/1 is generally considered the concentration below which warm water gamefish begin <br /> experiencing stress. <br /> The 1995 DO profiles show that the lake does experience periods of lower DO in the bottom <br /> waters, although-these waters are frequently mixed with the upper waters and DO is replenished. <br /> Lakes that mix continuously are called polymictic, meaning that the lake experiences frequent <br /> mixing. In 1995, Reshanau Lake was polymictic. This conclusion is supported by the observed <br /> DO and temperature profiles. <br /> -L Trophic Status <br /> Trophic State Indices (TSI) are indices comparing the biological productivity of lakes. These <br /> ' indices were developed by Carlson (1977) using TP, Secchi transparency, and chlorophyll-a data <br /> Table 4-2 presents the 1995 TSI for Reshanau Lake. <br /> TABLE 4-2 <br /> 1995 TROPHIC STATUS INDICES <br /> FOR RESHANAU LAKE <br /> Parameter TSI <br /> Total Phosphorus 71 <br /> Secchi Transparency 63 <br /> Chlorophyll-a 70 <br /> Average 68 <br /> MONTGOMERY WATSON Page 4-4 <br />