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Date Permissions Signed


Date of Award


Document Type

Masters Thesis

Degree Name

Master of Science (MS)


Environmental Sciences

First Advisor

Matthews, Robin A., 1952-

Second Advisor

Bodensteiner, Leo R., 1957-

Third Advisor

Homann, Peter S., 1953-


Lake Whatcom is a warm monomictic lake located east of the City of Bellingham, WA, U.S.A. and serves as the primary drinking water source for approximately 100,000 Whatcom County and City of Bellingham residents. Matthews et al. (2004) noted indicators of increasing algal productivity in the lake. My study quantified the amount of soluble, bioavailable, and total phosphorus in the Lake Whatcom watershed soils to help quantify the major sources of phosphorus entering the lake. In addition, I assessed the influence of soil factors (soil series, size fraction, aspect, elevation, pH, slope, percent organic matter, median particle size, and percent by volume sand, silt and clay) on bioavailable phosphorus concentrations. Organic matter, slope and elevation were found to be significantly positively correlated with bioavailable phosphorus. Total phosphorus was found to be a significant predictor of bioavailable phosphorus and produced a linear model with strong predictive capability (log10bap = 1.39log10tppers - 1.38; Adj. R2 = 0.79; p-value < 0.001). Total suspended solids data were used to predict concentrations of total and bioavailable phosphorus contributed by the watershed; the results were compared to actual total phosphorus concentrations measured in streams. The predicted phosphorus values were lower than actual stream phosphorus values, indicating that there were additional sources of phosphorus (e.g. residential runoff) entering the lake that supplement what was contributed by watershed soils. Alternatively, the difference between measured and predicted phosphorus concentrations may be due to high variability in phosphorus concentrations within the soils. The predicted and measured phosphorus values were closest during peak storm flows, suggesting that during high flow events, most of the phosphorus transported into the lake comes from watershed soils.





Western Washington University

OCLC Number


Subject – LCSH

Soils--Phosphorus content--Washington (State)--Whatcom, Lake, Watershed; Water--Phosphorus content--Washington (State)--Whatcom, Lake; Nutrient pollution of water--Washington (State)--Whatcom, Lake

Geographic Coverage

Whatcom, Lake (Wash.)




masters theses




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