Effects of impervious area and BMP implementation and design on storm runoff and water quality in eight small watersheds

Journal of the American Water Resources Association
By: , and 

Links

Abstract

The effects of increases in effective impervious area (EIA) and the implementation of water quality protection designed detention pond best management practices (BMPs) on storm runoff and stormwater quality were assessed in Gwinnett County, Georgia, for the period 2001-2008. Trends among eight small watersheds were compared, using a time trend study design. Significant trends were detected in three storm hydrologic metrics and in five water quality constituents that were adjusted for variability in storm characteristics and climate. Trends in EIA ranged from 0.10 to 1.35, and changes in EIA treated by BMPs ranged from 0.19 to 1.32; both expressed in units of percentage of drainage area per year. Trend relations indicated that for every 1% increase in watershed EIA, about 2.6, 1.1, and 1.5% increases in EIA treated by BMPs would be required to counteract the effects of EIA added to the watersheds on peak streamflow, stormwater yield, and storm streamflow runoff, respectively. Relations between trends in EIA, BMP implementation, and water quality were counterintuitive. This may be the result of (1) changes in constituent inputs in the watersheds, especially downstream of areas treated by BMPs; (2) BMPs may have increased the duration of stormflow that results in downstream channel erosion; and/or (3) spurious relationships between increases in EIA, BMP implementation, and constituent inputs with development rates.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effects of impervious area and BMP implementation and design on storm runoff and water quality in eight small watersheds
Series title Journal of the American Water Resources Association
DOI 10.1111/1752-1688.12501
Volume 53
Issue 2
Year Published 2017
Language English
Publisher Wiley
Contributing office(s) South Atlantic Water Science Center
Description 18 p.
First page 382
Last page 399