National Water-Quality Assessment (NAWQA) Program
Dallas-Fort Worth information sheet (2 pg PDF, 3.27 Mb)
This information sheet highlights selected findings of a comprehensive assessment by the National Water-Quality Assessment Program of the U.S. Geological Survey of the effects of urban development on stream ecosystems in nine metropolitan study areas. These are a few of the findings from the study in the Dallas-Fort Worth Metropolitan Area.
Prepared for November 30, 2012 Congressional briefing
Twenty nine sites were selected with drainage basin areas between about 10 to 112 square miles (27 to 291 square kilometers) and had minimal natural variability among them. The land use gradient went primarily from agriculture and grasslands to urban. Sites represented a broad range of urban intensity from low to high.
Landcover, urban intensity, and site locations
Time of study:
SSite selection in 2003.
Data collection from fall 2003 to fall 2004.
The Dallas-Fort Worth study area is located in north-central Texas. Major cities include Dallas, Fort Worth, Plano, Irving, and Arlington. The population in the Dallas-Fort Worth Metropolitan Area has increased 29.3 percent from 1990 to 2000 and was about 5.2 million people in 2000 (U.S. Census Bureau, 2000).
The study area is located in the upper drainage of the Trinity River Basin and overlays the Texas Blackland Prairie (Omernick, 1987), which is underlain by chalks, marls, limestones, and shales of Cretaceous age, and is a rolling to level plains dominated by little bluestem, yellow Indiangrass, sugar hackberry, bur oak, elm, and eastern cottonwood.
Land-use is dominated by row-crop, pasture, and rangeland, and urban land use in and around the Dallas-Fort Worth metropolitan area. Elevation in the study area ranges from about 262 to 886 feet (80 to 270 meters) above sea level (U.S. Geological survey, 2005).
The climate is semiarid with mean annual temperature of 65 degrees Fahrenheit (18.2 degrees Celsius) and mean annual rainfall of 41 inches (105 centimeters)(Daymet, 2005). Most precipitation occurs in the spring and also from summer thunderstorms. Annual surface runoff is about 2 inches (5 centimeters) per year.
Surface water in the study area is dominated by reservoirs, intra-basin transfers, diversion of water to municipalities, and wastewater effluent. Smaller streams are generally intermittent. Prairie streams support warm-water biological communities.
Moring, J.B., 2009, Effects of urbanization on the chemical, physical, and biological characteristics of small Blackland Prairie streams in and near the Dallas-Fort Worth metropolitan area, Texas: U.S. Geological Survey Scientific Investigations Report 2006–5101–C, 31 p.
For more information about the study area — http://tx.usgs.gov/projects/trin/