Modeling support for the Attoyac Bayou bacteria assessment using SELECT
K. Borel, L. Gregory, R. Karthikeyan
The Spatially Explicit Load Enrichment Calculation Tool (SELECT) methodology developed by Biological and Agricultural Engineering Department and Spatial Sciences Laboratory at Texas A&M University was used to independently characterize potential E. coli sources and estimate daily potential E. coli loads for the Attoyac Bayou watershed. SELECT is an analytical approach for developing an inventory of potential bacterial sources, particularly nonpoint source contributors, and distributing their potential bacterial loads based on land use and geographical location. A thorough understanding of the watershed and potential contributors that exist is necessary to estimate and assess bacterial load inputs. Land use classification data and data from state agencies, municipal sources, and local stakeholders on the number and distribution of pollution sources are used as inputs in a Geographical Information Systems (GIS) software format. The watershed is divided into multiple smaller subwatersheds based on elevation changes along tributaries and the main segment of the water body. Pollutant sources in the landscape can then be identified and targeted where they are most likely to have significant effects on water quality, rather than looking at contributions on a whole-watershed basis.