Characteristics of runoff from three watersheds in Montgomery County, Virginia

Abstract

The project included surface runoff and groundwater drainage measurements in addition to determinations of physical and chemical characteristics from three watersheds located within the same drainage basin in Montgomery County, Virginia.

Watershed number 1 included 80 acres of heavily forested land; number 2 consisted of 50 acres of pasture land and approximately 0.1 acre of barren land; and number 3 included 20 acres of brush land and steep embankments adjoining a paved highway.

The research period covered from March 15 to July 1, 1974. Dry weather groundwater drainage was sampled on four separate occasions. Surface runoff was sampled during five storms. A single composite sample was made from individual samples taken periodically from each watershed.

The amount of rainfall which was present as runoff from watershed number 3 averaged over 85 percent and was much greater than that from the other two watersheds.

Significant concentrations of TKN and N0₃-N were found in both groundwater drainage and surface runoff from all three watersheds. Steep embankments contributed the largest amount of TKN, N0₃-N, and COD, averaging 0.290, 0.203, and 19.2 lb/acre respectively in surface runoff.

Pasture and barren land contributed the most total phosphorus and suspended matter, with values averaging 0.084 lb/acre P0₄-P and 167 lb/acre SS.