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Geographic Information System (GIS) Characterization of Metal Loading in the Binational Tijuana River Watershed

Paul F. Englert, Christopher Brown, Carol Placchi, Richard M. Gersberg


This paper describes a geographic information system (GIS)-based, land use runoff model that estimates the annual mass emission of copper (Cu), lead (Pb), and zinc (Zn) from the binational Tijuana River watershed (TRW). This model estimates that the urbanized portion of the City of Tijuana, Mexico, accounted for 37 to 47 percent of the actual downstream loading of these metals to the Tijuana Estuary and coastal ocean. The fraction of loading contributed by open space was about the same (31-44%), although this land use comprised about 90 percent of the total watershed area. Modeled estimates of the annual mass emission of heavy metals are in reasonable agreement with actual measurements, particularly for zinc (within about 10%), thereby suggesting that GIS-based modeling may be useful for predicting nonpoint source pollutant loading in a variety of border development scenarios.

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Print ISSN: 0886-5655
Online ISSN: 2159-1229