Evaluating phosphorus migration from septic systems near Otsego Lake

The introduction of phosphorus into lakes from septic systems is a major concern. While that source is generally a small component of the total phosphorus load, the impacts can be substantial because it is in a soluble form, readily available to algae. Because most of near-lake septic system usage is seasonal, it is added to lakes at the height of the algal growing season (Harman, et al., 1997). Conversely, most non-point sources of phosphorus are not easily taken up by algae and are introduced into lakes during spring runoff events, which precede the onset of the first algal blooms (Albright, 1996). It has long been known that excessive phosphorus loading leads to eutrophication (i.e. Vollenweider, 1968), reflected by higher plant and algae growth, lower water clarity, lower concentrations of dissolved oxygen in the hypolimnion and the potential loss of potability. Previous research by the Biological Field Station has focused on sampling for fecal coliform bacteria (Herring, 2000; Green, 2001), the rationale being that chronic “hot spots” might indicate failing systems. However, it is now recognized that functioning systems, having adequate percolation rates, can contribute substantial amounts of phosphorus (Ptacek, 1998; Baker et al., 1998; Zanini et al., 1998). More extensive research is necessary in order to verify the extent of this locally. More importantly, technologies are described that can efficiently intercept that phosphorus, preventing its reaching ground or surface waters (Baker et. al, 1998).