TROPHIC STATE AND EUTROPHICATION

    Lake Trafford may be classified as a hypereutrophic lake, which means that there is excessive aquatic plant production (Wetzel, 1983) as commonly measured by phytoplankton concentrations.  Phytoplankton productivity, a common measure of trophic state, is directly related to excessive quantities of nutrients in the water column, which state, is directly related to excessive quantities of nutrients in the water column, which have been high in the lake (Fig.8). Comparison of total phosphorous concentrations in the water column with Chlorophyll-a concentrations demonstrate a direct correlation between increased phosphorous levels and increased phytopplankton productivity (Fig. 8). Reduction of phosphorous loading rates should reduce aquatic plant and phytoplankton reproduction rates and move the trophic state of the lake toward a eutrophic-mesotrophic state.  Data for 1997 documents the lake's Trophic State Index as Poor (Fig. 9) with the highest numbers coinciding with a fish kill.

    Anecdotal data suggests that as recently as 50 years ago, the visible lake substrate was sand.  Organic sediment derived from dead and decaying aquatic vegetation currently covers the lake bottom to a thickness of as much as eight feet.  Hydrilla is the dominant aquatic plant across much of the lake with a variety of other exotic or noxious plants now populating the nearshore substrate and shore area (Fig. 10).  As recently as February, 1996, the commonly employed aquatic control methodology was the application of chemical herbicides with the trated plant material accumulating in the lake to decompose (Fig. 11).  The blanket of organic sediment that has been generated has resulted in a much shallower lake (Fig. 12) relative to the depth over and original sand substrate (Fig. 12 & 13).