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4.2.3.5 Public Use and Related Water_Ouality Concerns Recreational use of Echo Lake is currently limited to lake residents who use the lake for swimming, canoeing, small rowboats, and passive aesthetic viewing. Residents comment that the lake's picturesque shoreline is reminiscent of northern Minnesota lakes, despite its poor water quality. A variety of wildlife, birds, and waterfowl have made their homes in and around the lake and area residents enjoy walking around the lake to view them. The City of Mahtomedi has made plans to install a public access to increase recreational use of Echo Lake. The access will consist of a path to carry canoes and small non -motorized craft to the lake. Also, a City ordinance restricts lake boat use to non -motorized craft. The current and the expected future use of Echo Lake conflict with its current water quality. According to MPCA surveys of citizen volunteers and MPCA staff members, the lake's current water quality places it in a category of being undesirable for swimming and boating activities. Also, MPCA surveys indicate total phosphorus concentrations should remain below 0.050 mg/L if boating and even partial support of swimmable use is to be achieved (MPCA, 1990). Above this total phosphorus range, the frequency of transparencies less than 1 meter and the occurrence of severe algal blooms increases dramatically. Water transparency less than one meter and frequent algal blooms make a Take undesirable for boating and for any swimmable use. As shown on Figure 4-3, the average summer phosphorus concentration in Echo Lake has been consistently above 0.060 mg/L, except for a single sampling event in 1975. The lake's average Secchi transparency has consistently been less than 1 meter (see Figure 4-3), Chlorophyll concentrations have increased steadily since monitoring began. The 1991 summer average of 94 mg/m3 indicates severe algal blooms occur throughout the summer months. The DNR has no fisheries information and does not currently manage the fisheries in Echo Lake. However, once the public access is developed, the DNR may be interested in surveying the current fisheries of the lake. The DNR may also find it necessary to monitor the winter oxygen concentration in the lake before making any fisheries management decisions. The lake may be suitable for bluegills and largemouth bass, if a sufficient winter oxygen concentration exists to permit their survival. Echo Lake residents are concerned about the algal blooms which give the lake a green, murky appearance during the summer months. Some residents wish to have the lake's fisheries managed, while other residents prefer no management. Other concerns of area residents include: ■ Maintenance of the Echo Lake water level at its historic average level. Residents are concerned that the lake water level may rise as development occurs around the lake. ■ Increased sediment discharge into Echo Lake as a result of construction during development. Residents want more stringent requirements on developers to protect the lake during future developments. ■ Inadequate treatment of stormwater from the 916 Vocational -Technical School property, which could be improved. ■ Setbacks from the lake shoreline for future development, to preserve the native vegetation. Preserving Echo Lake's natural shoreline is a priority management option for the lake, since aesthetic viewing of the lake is important. 23\82\045\SEC4.RPT\KMH 9 DRAFT: June 23, 1994