Lake Assessment Program - Long Lake, Otter Tail County

Long Lake is located in Otter Tail County near the town of Vergas. This lake has a surface area of 1,273 acres and a maximum depth of 128 feet. Mean depth of the lake is estimated at 28 feet. The immediate watershed of Long Lake is approximately 7,418 acres (including the lake surface area). Land use in the watershed is characterized by open water/marsh (21 percent), forested (19 percent), cultivated (45 percent), grassland/pasture (12 percent), and residential/urban areas (the remaining 3 percent). These land use percentages are typical of what would be expected for lake watersheds in the North Central Hardwood Forests (NCHF) Ecoregion of the state. Long Lake was sampled during the summer of 1999 by Minnesota Pollution Control Agency (MPCA) staff. Water quality data collected during the study revealed a summer mean total phosphorus concentration of 20 ?g/L, chlorophyll-a concentration of 6 ?g/L, and a Secchi transparency of 8.8 feet. All three of these values are well within or below (better than) the typical range exhibited by reference lakes in the NCHF ecoregion. The parameters: total phosphorus, chlorophyll-a, and Secchi transparency help to characterize the trophic status of a lake. For Long Lake, these measures indicate mesotrophic conditions.
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Minnesota Water Research Digital Library
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