LAND USE MAPPING OF THE LOWER RIO GRANDE VALLEY OF TEXAS AND NORTHEAST MEXICO

The University of Texas at Brownsville (UTB) and the Bureau of Economic Geology (BEG) are participating in an Environmental Protection Agency (EPA) funded project relating to mapping of riparian vegetation in the Lower Rio Grande Valley of Texas and Northeastern Mexico. Using a Geographic Information System (GIS), UTB is creating a current landuse map of the Lower Rio Grande Valley (LRGV). The area of study stretches 193 km from Falcon Dam in the northwest to the mouth of the Rio Grande in the southeast. In an effort to explain the changes in the ecological resources of this region, primarily riparian vegetation, a current land use map is a necessity. Primary resources for the project include USGS Digital Orthophotoquads (DOQ's) dated 1995 and field observation. Existing digital coverages of geology, soils, hydrology, wetlands and the USGS land use/land cover map for the Arroyo Colorado aid in the classification process and are used as layers of a GIS study. A digitized 1960 land use map of the LRGV provides an important tool for comparison and assessment of the changes occurring in the landscape of the LRGV over the past 40 yrs. When complete, an assessment can be made showing the effects of human influence on land use and natural vegetation within the study area.