By Hillary Kenyon and Dr. George Knoecklein
Internal Loading versus External Loading Dilemma
The lake phosphorus loading model used a common internal release rate of 1mg/m2/day to estimate 60kg/yr TP load. However, that release rate needs to be refined to better reflect West Hill Pond.
External nutrient load from appears to be different in base-flow vs. stormwater flows. Stormwater flows had lower phosphorus and nitrate than the base-flow values suggesting that largest contribution of water to base-flows of streams is from septic systems. These concentrations appear to be diluted by rainwater, suggesting that stormwater runoff drains minor impervious areas and is collecting only minimal nutrients from these surfaces.
o Continued monitoring of streams during both base-flows and storm events is recommended.
o A perimeter study of seepage water during the fullest extent of winter drawdown is recommended.
o A Very Near Shore Conductivity Sweep during late summer is suggested.