Design of Stormwater Monitoring Programs for Industrial Sites

Haejin Lee¹ and Michael K. Stenstrom^2*

¹ United States Department of Agriculture, Natural Resources Conservation Service, El Centro Office, 177 N. Imperial Ave., El Centro, California 92243, USA

² Department of Civil and Environmental Engineering, 5714 Boelter Hall, University of California, Los Angeles, Los Angeles, California 90095, USA

Abstract

Stormwater runoff is now the leading source of water pollution in United States, and stormwater monitoring programs have only recently been developed.  This paper evaluates more than 20 stormwater monitoring programs and datasets to determine their usefulness in characterizing discharges and achieving their ultimate goal of reducing stormwater pollution. The monitoring results are highly variable, with coefficients of variation that are 2 to 60 times higher than observed in wastewater monitoring programs. Industrial landuse is an important source of metals, although the monitoring programs could not differentiate metals contribution from different types of industries. Data from California, which has distinct dry periods showed a seasonal first flush; data from Connecticut did not show a seasonal first flush. Recommendations for improving monitoring programs include using composite samplers, selecting alternate or additional water quality parameters, alternate timing of sample collection, and strategies that sample a subset of the total permittees using more sophisticated methods.

Keywords: First flush; Industrial General Permit; Monitoring; Municipal Permit; Stormwater