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III. HYDROLOGIC AND RESOURCE INVENTORY The campus soil conditions are described as sandy lake sediment in the Geologic Atlas for Ramsey County, which was prepared by the Minnesota Geological Survey in 1992. This would include fine -to -medium sand and silt and clay. These are probably former lake deposits that may have been partially confined by stagnant ice. The campus forms a peninsula on northerly and westerly sides into Lake Johanna in Arden Hills and on its westerly side into Little Lake Johanna in Roseville. Figure No. 1 shows the existing campus watersheds. Lake Johanna (DNR Lake ID number 62-0078 and hydrologic unit code 7010206) is located in Arden Hills and has an area of 213 acres and maximum depth of 43 feet. Its dominant bottom substrate is sand and gravel, and muck with abundant plant growth to a maximum depth of 10 feet. Bluegills are the most abundant species sampled in Lake Johanna. The average length captured during the survey was 5.53 inches. Less than 1 % of the catch exceeded 7 inches. Pumpkinseed and hybrid sunfish were also sampled in high abundance for this type of lake. Black crappies were not as abundant as previous years. The population of this species has been variable. The average length sampled was slightly larger than 7 inches. Walleye were sampled in average numbers for this type of lake. Half the walleyes caught were 20 inches and longer. Northern pike were abundant when compared to historical levels on this lake. The average size caught was 26.62 inches and 4.37 pounds. Over 70% of the pike sampled exceeded 25 inches. Yellow perch were found to be abundant but small. Two thousand six hundred and seventy seven (2,677) Lake level records for Lake Johanna have been record since January 5, 1924, to the present (Figure No. 2). The highest and lowest recorded water levels were: 881.27 feet on July 3, 1978, and 870.35 feet on July 21, 1926, respectively, which is a range of 10.92 feet. The most recent lake level reading was 878.51 on June 30, 2006. The MDNR has established an Ordinary High Water (OHW) level of 878 feet which means that any work below that level would require a permit from the MDNR. Northwestern College Master Plan 4 13529.000 Stormwater Management Study