Sediment Impacts from Natural Gas Exploration and Production Sites

Abstract

Oil and gas development, exploration, and production requires construction of a well site, access roads, and pipelines, all of which have the potential for accelerating erosion due to land cover modifications, increased slopes, and flow concentration. The objective of this paper was to characterize storm water runoff from gas well sites in North Central Texas. Flow proportioned storm water samples were collected over a one-year period at the edge of three sites using small weirs and automated sampling equipment. Total Suspended Solids (TSS) concentrations ranged from 32 to 14,350 mg/L with the median Event Mean Concentration (EMC) of 30 storms equaling 2,624 mg/L. Annual sediment yields ranged from 15.7 to 29.7 t/ha. Measured annual yields compared well to modeled yields, and both TSS concentrations and overall yields were well within the ranges previously reported for typical construction site studies. The similarity between the measured annual yield and the modeled annual yield indicates that erosion models could be a useful tool for estimating potential storm water impacts from gas well sites and for evaluating site management alternatives. Also, the similarity to typical construction sites suggests that gas well sites should be regulated and operated in a manner similar to typical construction sites.