There are a significant number of water bodies (streams, reservoirs, sub-watersheds, or sections of reservoirs or sub-watersheds) in the Grand Lake Watershed that are listed as “impaired” or “threatened”. The major problem is excessive algae growth caused by high nutrient levels. This creates algal blooms which cause low dissolved oxygen conditions, which adversely affect aquatic life, which affects the taste and odor of the water, and which can produce toxins harmful to other aquatic organisms, wildlife, domestic animals and humans.

Elevated nutrient levels, particularily phosphrous, pose water quality risks to the four major Grand Lake Watershed reserviors and lakes: Marion Reservior, Council Grove Reservior, John Redmond Reservoir, and Grand Lake O’ The Cherokees.

Other conditions of concern are sedimentation caused by soil erosion, fecal bacteria, heavy metals and acids from mining areas, and isolated instances of pesticide contamination.

In accordance with the federal Clean Water Act, states are beginning to establish total maximum daily loads (TMDLs) for pollutants causing water body impairments. States then determine the load reductions required to accomplish the TDML. Meeting the TMDLs for the nutrients phosphorus and nitrogen in various water bodies in the watershed will require reductions of from 20 to 90 percent. These types of reductions will only be accomplished with effective water quality improvement plans.