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Temporal variation in spatial sources of mercury loading to rivers (presentation)
Citation:
RAIKOW, D. AND E. D'Amico. Temporal variation in spatial sources of mercury loading to rivers (presentation). Presented at Third International Symposium on Ecology and Biodiversity in Large Rivers of Northeast Asia and North America, Memphis, TN, September 20 - 24, 2010.
Impact/Purpose:
We examined how the spatial configuration of source areas for runoff varied over time in a watershed contaminated with mercury in order to understand processes governing material loading to rivers.
Description:
Source areas within the Fox River watershed (WI, USA) were mapped for individual discharge events. The spatial distribution of source areas varied between, and over the duration of, individual discharge events. The percent contribution of runoff by land cover type within source areas was quantified and compared to areal abundance of land covers int he watershed. Agricultural land dominated discharge sources, consistent with known patterns of mercury loading to regional rivers. Contributions of runoff by land cover types, however, varied over time. Moreover the degree to which different land cover types acted as source areas differed from their abundance in the watershed. Hence areal quantifications of land cover within a watershed may not accuratgely represent what land covers actually act as source areas over different time periods. Therefore a source areabased approach may yield more accurate spatial analyses of material loading patterns than a watershed-based approach.