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report that the water quality of the lake varies somewhat from year to year. During 1990, they did not consider the water quality of the lake to be objectionable. However, during 1991, constant algal blooms caused the lake to be excessively green throughout the ice -free period, f and the decaying algae produced objectionable odors. During 1993, the lake was perceived by residents to have good water quality. Water quality data collected from Long Lake are presented on Figure 4-5. 1990 data indicated Long Lake exhibited relatively poor water quality. In contrast, 1993 data indicated Long Lake exhibited generally good water quality. Antecedent drought conditions may have resulted in less flow through the lake in 1990 than in 1993. The lower flushing rate in 1990 may have resulted in a greater accumulation of phosphorus from internal loading than occurred during 1993. The data suggest internal phosphorus loading plays an important role in the lake's water quality. The 1993 data were compared to criteria used to denote a lake's nutrient "status," and the effects of the nutrients on the general water quality and/or trophic conditions of a water body (NALMS, 1988). Based on a comparison of a lake's total phosphorus concentration to these criteria, Long Lake would be assigned a trophic status of mesotrophic. This means that the lake contains moderate quantities of nutrients. An evaluation of the effects of the nutrients on the general water quality of the lake results in a classification of mesotrophic to somewhat eutrophic. This means that the lake is generally responding to the nutrient load as expected. A comparison of 1990 data to these criteria results in a classification of eutrophic to hypereutrophic indicating the lake is rich in nutrients and extremely productive. Results of a trend analysis of Long Lake water quality data showed no significant changes in total phosphorus, chlorophyll a or transparency (Secchi disc) over the 1971 -1990 period. A significant change in all three indicators is needed to indicate a significant change in water quality. 4.2.5.5P-ubl-i�tJseend Related�Alater-O- ual-its Coneerns - - Recreational use of Long Lake consists of swimming (by area residents), fishing, canoeing, sailing, waterbiking, power boating (by area residents), and passive uses, such as aesthetic viewing. Recreational use of the lake is expected to increase if an improved access is completed. In 1992, the DNR and the City of Mahtomedi proposed to install a public access off of Long Lake Road. Residents of Pine Springs and Mahtomedi objected to the planned access because they believe the lake is too small to safely accommodate power boats, visibility problems would make it difficult to patrol the lake from the public access, no suitable parking would be available, and the proposed access would frequently be inundated with water, rendering it useless much of the time. The lake residents proposed a carry -on access for non - motorized craft. The DNR would not fund the installation of the carry -on access, so the access plan was dropped. The current and future desired recreational uses of Long Lake were not in conflict with its 1993 water quality. However, a conflict was noted in 1990. According to MPCA surveys of citizen volunteers and MPCA staff members regarding lake water quality, Long Lake's current (i.e., 1993) water quality places it in a category of being suitable for all recreational activities, including swimming and boating activities. The lake's water quality during 1990 made it undesirable for swimming and boating activities. As shown on Figure 4-5, the average summer Secchi value during 1990 was less than one meter and chlorophyll a concentrations averaged 36.7 mg/m'. The MPCA has found that water transparencies less than one meter and frequent algal blooms make a lake undesirable for boating and for any swimmable use (MPCA, 1990). These values correspond to Trophic State Index (TSI) values of 63 and 66 which indicate, 23\82\045\SEC4.RPT\KMH 14 DRAFT: June 23, 1994