3.1 Water Quality

  1. The water quality in Long Lake has consistently been scored in the C-D grade range on the District's annual lake report cards.  The mean summer 2004 total phosphorus concentration was 76 ?g/L, in excess of the District's 40-50 ?g/L goal.   Based on this monitoring history Long Lake's water quality is partially supportive of swimming.   The mean summer 2004 total phosphorus concentration of 118 ?g/L for Tanager Lake exceeds its interim goal of 70 ?g/L.  The state standard, and thus the long-term goal for Long and Tanager Lakes is 40 ?g/L.   Phosphorus loading reductions would be necessary to achieve either of the desired interim or long-term goal in-lake phosphorus concentrations.   Little or no data is available for Holy Name, Wolsfeld, and Mooney Lakes.
  2. Phosphorus loads in Long Lake Creek increase upstream to downstream, and dissolved oxygen can fall below the state standard during low flows.
  3. Development is expected to continue in this subwatershed, and that future land use change is predicted to increase nutrient and TSS loads as well as increase the volume of stormwater runoff, potentially further degrading water quality in lakes, streams, and wetlands.
  4. Erosion and channel gullies in the Wolsfeld Woods Scientific and Natural Area (SNA) may be contributing sediment and nutrients to Wolsfeld Lake (within the SNA).