Inventory of Ponds in the Brazos and Colorado River (Texas) Drainages, from NASA Color Infrared Photography.
Year: 1986
Type: article
Abstract: NASA color infrared photography was used to inventory the farm ponds of the Colorado and Brazos River basins in Texas.Ponds in randomly selected blocks within larger photographic frames were counted and placed in size classes.In the 65 photographic frames examined of the Colorado River basin 12,367 ponds were identified, and 2,598 ponds were identified in the 7 frames examined of the Brazos River basin.Ponds were assigned to five size classes: class 1, < 1.25 ha; class 2, 1.25-2.5 ha; class 3, 2.5-5 ha; class 4, 5-11.25 ha; class 5, > 11.25 ha.Densities in ponds per km2 by size class for the Brazos and Colorado River basins respectively were: class 1 -1.7,0.97;class 2-0.1,0.06;class 3-0.02, 0.01; class 4-0.003, 0.003; and class 5-0.002, 0.004.In the Colorado River basin 92.8 percent of the total ponds counted fell into size class 1 ( < 1.25 ha) and 5.6 percent of the total count fell into size class 2 (1.25-2.50ha).In the Brazos River basin these two size groups constituted 93.3 and 5.5 percent of the total ponds counted respectively.Counts in all other size groups were 1 percent or less of the total.The Colorado River basin pond densities (number per unit area) tended to be low (> 1.5 pond/ha) in the immediate vicinity of the Gulf Coast, and in the Texas High Plains, with a wide range of densities (1.5-3.25 ponds/ha) in the region between the Coastal Plain and the High Plains.In the Brazos River basin, densities tended to increase with distance from the coast.The counting blocks were from 2.1 to 2.3 km2 wide, and there was no significant change in pond density with distance from the river channel at this resolution.In a 10 factor stepwise regression model, the factor which explained the most variation in pond count density was average slope, (here defined as the maximum elevation in the county minus the minimum elevation) followed by population density and rainfall, in order of importance.Using the simplifying assumption that all ponds have watersheds which are hydrologically independent, we calculate that in 28 percent of the frames, over one half of land surface would have to be in pond watershed to maintain the pond surface area in the frame.The data also suggest that there may be significant differences in pond density among soil associations ranging from 3.028 ± 0.197 ponds/km2 in the Castell-Ponotoc-Lignon Soil Association to 0.172 ± 0.123 ponds/km2 in the Amarillo-Acuff-Mansker Soil Association.Using pond density data from this study it is estimated that the number of ponds 1.25 ha and smaller is 102,000 for the Colorado River basin, and 191,000 for the Brazos River basin.If the mean density for the two watersheds is applied to the State of Texas, with the Rio Grande River basin excluded, there were an estimated 782 ,000 ponds 1.25 ha and smaller, and an estimated 840,000 ponds of all sizes in the state, as of 1970.
Authors: William J. Clark, Timothy A. Springer
Language: English
Subfield: Ocean Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2289194191