Seasonal disconnect between streamflow and retention shapes riverine nitrogen export in the Willamette River Basin, Oregon.

ABSTRACT: Watershed nutrient balance studies traditionally focus on annual fluxes. In areas with strongly seasonal, Mediterranean-type climate regimes, riverine nutrient export may be greater during wet seasons when hydrologic forcing overwhelms or bypasses retention mechanisms. By combining data on riverine export with spatially detailed nutrient inputs, we examine how nitrogen (N) supply, retention, and streamflow shape annual and seasonal riverine N export in Oregon's Willamette River Basin (WRB). The WRB has pronounced dry summers and wet winters, and the distribution of farmland, cities and forests create significant spatial variations in N inputs. Local data on N inputs were coupled with streamflow and chemistry to calculate fractional N export for 22 WRB sub-watersheds in the mid-2000s. For t

SUBMITTER: Compton JE 

PROVIDER: S-EPMC7286437 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature