A GIS Model For Predicting Occurrences of Illegal Dumping

Stephen C. Brown, Ph.D.
Vincent A. Romeo

Center for Water Research
University of Texas at San Antonio

Susan K. Stuver, M.S.
City of San Antonio

Background

As the cost of disposing of trash, garbage and construction materials continues to increase, it is likely that there will also be increasing incidences of illegal dumping across the United States. San Antonio, Texas will almost certainly be no exception. This paper presents the current status and initial results of a study being conducted by the University of Texas at San Antonio's Center for Water Research for understanding the influences and occurrences of illegal dumping. When the study is complete, it is a goal to build a template GIS model in ModelBuilder for creating predictive models of an area's susceptibility to illegal dumping.

Methodology

The 78249 zip code area in San Antonio, Texas was chosen for this study because of its proximity to the University of Texas at San Antonio and because of the seemingly large occurrence of illegal dumping in the area. For the purpose of this study, illegal dumpsites are defined as any intentional and illegal abandonment of household or industrial material on public or private property.

At the time this paper was written, approximately 80% of the 78249 zip code area had been visually surveyed for illegal dumps by methodically driving the area. As sites were located, their position and contents were mapped with a Trimble GeoExplorer III Global Positioning System (GPS) receiver utilizing real-time corrections from a Trimble Beacon on a Belt (BoB).

Length, width and height of each dumpsite was estimated to determine total volume. Each site was assigned a visibility rating of 1-3. A visibility rating of 1 meant the site had very low visibility and a 3 meant high visibility. Conversely, each site was also given an accessibility rating of 1-3. An accessibility rating of 1 meant the site was hard to reach and a rating of 3 meant the site was easy to reach. At the beginning of this study it was thought that areas with low visibility and high accessibility would be more susceptible to illegal dumping. Collected data was analyzed using ArcView 3.2.

Summary of Initial Results

104 illegal dumpsites in the 78249 zip code were mapped using a Global Positioning System (GPS) receiver. Percent content of each dumpsite was estimated in six different categories and a visibility and accessibility rating of the site were assigned. At 45%, brush represented the largest component of the dumpsites and municipal solid waste (household waste) represented the second largest category at 42%. Tires constituted 5%, asbestos containing material was 4%, industrial solid waste 2% and hazardous material 2% of total content. High accessibility to and low visibility of dumpsites did not appear to be as strong an influence on dumpsite occurrences as thought at the beginning of the study. Total volume of the 104 dumpsites mapped was 717.5 square meters.

Author's Contact Information:

Stephen C. Brown
Vincent A. Romeo
Department of Earth and Environmental Sciences
University of Texas at San Antonio
6900 N. Loop 1604 W.
San Antonio, Texas, 78249 USA

(210) 458-4956 (voice)
sbrown@utsa.edu (email)

Susan K. Stuver
Environmental Services Division
City of San Antonio
P.O. Box 839966
San Antonio, Texas 78283 USA

(210) 207-6449 (voice)
sstuver@ci.sat.tx.us