Estimation of nonpoint sources of phosphorus for lakes in the Puget Sound region, Washington

Water and nutrient budgets for Vancouver Lake, Vancouver, Washington, October 2010-October 2012

“…The total phosphorus and orthophosphate loads were assumed equal, because we do not have estimates of orthophosphate concentrations in rainwater, and ranged from 0 to 90 lb/month, with an average of 40 lb/month for the period of study (tables 11 and 12). For phosphorus, these loads are consistent with previously published estimates of watershed loading from precipitation in Gilliom (1983), Ebbert (1985), and Embrey and Inkpen (1998), indicating that our assumption for phosphorus concentration in precipitation is reasonable. …”

Nutrient and trace-element enrichment of Coeur d'Alene Lake, Idaho

“…The efficiency of wastewater treatment by septic tanks may be quite variable and often is a function of age. Gilliom (1983) reported that older septic-tank systems contributed more phosphorus to Puget Sound region lakes than did newer systems. Gilliom also noted that long lag times are possible between installation of a septic-tank system and detection of its effects on phosphorus concentrations in a lake.…”

Relationships between water quality and phosphorus concentrations for lakes of the Puget Sound region, Washington

“…The application of each method is explained along with its derivation. The methods developed in this study complement previously developed methods for estimating background (predevelopment) P loadings and concentrations (Gilliom, 1981), and P loadings from nonpoint sources (Gilliom, 1982). STUDY …”