Estimation of Nutrient Loading from the Great Lakes Watershed Using Binational SPARROW Models

Session: Poster Session

Dale Robertson, U.S. Geological Survey, dzrobert@usgs.gov
David Saad, U.S. Geological Survey, dasaad@usgs.gov
Glenn Benoy, International Joint Commission, benoyg@ottawa.ijc.org
Ivana Vouk, ivana.vouk@nrc-cnrc.gc.ca
Richard Burcher, National Research Council of Canada, richard.burcher@nrc.gc.ca
Michael Laitta, Laittam@washington.ijc.org
Wayne Jenkinson, International Joint Commission - Canada Section, JenkinsonW@ottawa.ijc.org

Abstract

Excessive nutrients (primarily phosphorus, P and nitrogen, N) are a persistent problem in streams, lakes and estuaries throughout the Great Lakes region of Canada and the United States.  To help understand the distribution, origin and sources of nutrients delivered to the lakes, SPAtially Referenced Regressions On Watershed attributes (SPARROW) watershed models have been developed for this region, for environmental practices that were place in 2002.  SPARROW models require comprehensive data to describe contaminant sources and watershed characteristics throughout the entire area being modeled and are calibrated against estimated loads at monitoring locations throughout the basin. The binational extent of this area required extensive cooperation between multiple federal, state/provincial, and local agencies and scientists to create the harmonized datasets needed for model input. Model output includes estimated loads at more than 800,000 stream reaches. Model results from the 2002 models have been used to: 1) estimate the P and N input to each Great Lake, as well as adjacent watersheds; 2) compare loading and yields from various tributaries and governances; and 3) estimate the relative importance of each nutrient source. The binational SPARROW models are currently being updated to represent environmental practices that were in place in 2012.