Clean Water Advocacy - Newsroom - AMSA in the News
No. 219
Thursday, November 15, 2001 Page A-12
ISSN 1521-9402
News
Water Pollution
Numeric Limits for Storm Water Pollutants Seen as Increasing Trend in Agency
Permits
SAVANNAH--Numeric limits for pollutants in storm water have been included in
recent Clean Water Act permits issued by the Environmental Protection Agency in
what municipal officials said Nov. 14 could be an increasing practice by
regulators.
"EPA is looking like they're heading toward putting numeric limits in storm
water," Michele Pla, vice president of CH2M Hill, a consulting firm in Oakland,
Calif., said at a legal conference sponsored by the Association of Metropolitan
Sewerage Agencies. "We're seeing it in Southern California."
Permitting authorities, she said, are starting to set numeric discharge limits
subject to the waste load allocations established in the total maximum daily
load for the receiving water. Not only are numeric limits being set, but the
National Pollutant Discharge Elimination System permits also require the
discharger to demonstrate how the best management practices employed to control
the storm water will help achieve those limits.
The Clean Water Act established a storm water control program that has been
implemented in two phases. The first phase applied to municipalities with
populations of 100,000 or more and construction sites affecting more than five
acres. The second phase was issued in 1999 and applied to smaller cities and
construction sites.
Mostly, the controls involve the implementation of best management practices
designed to reduce the amount of runoff going to the publicly owned treatment
works or directly into the receiving waters. Municipalities have to develop
storm water management plans that call for identifying storm water outfalls and
possible pollutants; reducing pollutants from industrial, residential, and
commercial operations; and controlling storm water from new development and
redevelopment projects.
Practice Questioned
Several permittees have said including numeric limits in the storm water permit
goes beyond Clean Water Act dictates, Pla said.
One such permit was issued to San Diego. However, representatives of the
building industry there, not the city, are challenging the permit. Action on a
challenge to a permit issued in Orange County, Calif., is also pending, Pla
said.
Los Angeles faces another situation that city officials said they found
perplexing. The city was issued a permit containing numeric standards based on a
TMDL for trash, Pla said.
The TMDL, which is a plan to allocate pollutant loadings among dischargers to
impaired waters, was based on a narrative standard for trash contained in the
state's water quality plan. This narrative standard was "turned into a zero
trash target in the TMDL," she said.
"They're being given numeric standards for how much trash they have to reduce to
get to zero trash at the end of the mandated period," she said.
The problem, she said, is not only how to meet the standard, but that EPA has no
data on the assimilative capacity of the water body for trash nor any standard
for translating narrative criteria into a number.
Chris Westhoff, assistant city attorney for the Los Angeles Department of Public
Works, said he did not know how the city was supposed to meet the trash
standard.
"They want us to dictate the personal practices of 4 million individuals in the
city," he said. "How are we supposed to do that?"
By Susan Bruninga