Hold the Dirt: Sedimentation and Urban Growth in an Alabama Watershed

A highway construction-caused sediment plume impacting the J.B. Converse Reservoir, along with transportation and land cover classifications inputs for the SLEUTH model. Image Credit: Thigpen Photography and DEVELOP Mobile Team.

A highway construction-caused sediment plume impacting the J.B. Converse Reservoir, along with transportation and land cover classifications inputs for the SLEUTH model. Image Credit: Thigpen Photography and DEVELOP Mobile Team.



Authors: Walt Clark, Taylor Beard, Deborah Mims, James Pickett, Courtney Richards, Allison Bowman

Mentors/Advisors (affiliation): Joe Spruce (Computer Sciences Corporation/CSC, Stennis Space Center), Dr. Bernard Eichold (Mobile County Health Department), Dr. Kenton Ross (Langley Research Center), Karen Jordan (University of South Alabama)

Team Location: Mobile County Health Department, Mobile, Alabama; and NASA Langley Research Center, Hampton, Virginia

Abstract: The J.B. Converse-Big Creek Lake is the result of a manmade dam across Big Creek, a tributary of the Escatawpa River. The reservoir is the primary source of drinking water for the Mobile, Alabama, metropolitan area. As such, protection of the reservoir’s watershed is paramount to the health and well-being of the people of Mobile. Threats to the watershed, in particular the construction of the Highway 98 Corridor in the northern area of the watershed, were the focus of this research for future potential harms and effects upon the watershed. In order to assess the effects and potential damage of an extended road system through the watershed, the Mobile County Health Department and the Mobile NASA Develop office partnered with the Mobile Area Water and Sewer System (MAWSS) to conduct research for the direct impact of the new construction. Key areas of interest for research are: past and future silt and carbon loading of the watershed and Mobile’s water supply, and urban development within the watershed resulting from the construction and existence of the Highway 98 Corridor. Specific changes in land use dating back to 1983 were the focus for urban development, including changes in roads, population, traffic and vegetation in the study area. Water quality assessments show sediment loading based on derived total suspended sediment measurements taken by the MODIS instrument aboard the Aqua and Terra satellites.

The classification system is based on a combination of the U.S. Geological Survey’s (USGS) National Land Cover Database (NLCD) and National Oceanic Atmospheric Administration (NOAA) land use systems. Both of the systems are part of the Multi-resolution Land Characteristics (MRLC) Consortium lead by USGS. The land use change analysis is phase 1 of a two-semester study, culminating in the use of the Slope, Land Use, Exclusion, Urban Extent, Transportation, and Hillshade (SLEUTH) modeling program to predict future expansion in urbanization and resulting changes in total organic carbon (TOC) rates in the tributary system, lake waters, and sediments within Big Creek Lake Watershed. This imagery combined with NASA Earth observations provided partners with an analysis of sedimentation events in Big Creek Lake as urbanization and construction increases.



Transcript available here.


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