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I I a I I , I . I I, I I I I I 8.15.01 Josephine and Round lakes both fully support swimmable use classification, although they are sensitive to increases in phosphorus nutrient loading. Lake Johanna only partially supports swimmable use classification due to algae blooms and low transparency for a significant portion of the summer. Karth, Little Lake Johanna and Valentine lakes do not support swimmable use classification due to severe and frequent algae blooms and low transparency for most of the summer. Round, Karth, Little Lake Johanna and Valentine lakes have either small surface areas or are quite shallow in average depth and therefore would not be considered likely candidates for swimmable use, However, water quality data in support or non-support of this use is important for wildlife management of these water bodies. Lake Josephine Assessment Report The MPCA along with MDNR, Ramsey County Public Works, RCWD and Josephine Lake Association issued a Lake Assessment Report for Josephine Lake in 1998. Pertinent portions from that report are as follows: (page jji) A good historical data base is available for assessing trends in water quality of Lake Josephine. These data include 22 years of Secchi data and several years of water chemistry data. Based on an analysis of 22 years of CLMP, MPCA, DNR, Met. Council, Ramsey County, and two environmental consulting firm's Secchi transparency data, Lake Josephine exhibited a significant improvement in transparency over time (R. = 0.52; p={J.()OO8). Summer mean Secchi transparency measures ranged from 2.3 to 4.3 feet from 1975-1979. In contrast, from 1981-1989 summer-mean Secchi ranged from 3.0 to 10.2 feet and from 1990-1998 summer-mean Secchi ranged from 5.2 to 12.1 feet. Summer-mean total phosphorus and chlorophyll-a concentrations exhibited a decline over this time period as welL (page 3) Lake Josephine's watershed is relatively small at about 734 acres, excluding the lake. The vast majority (96%) of the watershed is in urban/residential lake use. This percentage, although not typical for lakes in the North Central Hardwood Forest ecoregion, is rather typieal for lakes in the Twin Cities metro area. Little Lake Josephine is about 12 acres in size, much of which is covered by cattails and emergent vegetation; however, the open water portion has maximum depth of 25 feet. Originally, about 260 acres drained through Little Lake Josephine prior to entering Lake Josephine. In 1980, a project conducted by the RCWD, in consultation with E.A. Hickok Engineering, resulted in an additional 220 acres of direet drainage from Lake Josephine watershed City of Arden Hills, Minnesota Local Water Resource Management Plan A-ARDEN0101.00 Page 25