Texas. Dept. of Transportation

PDF

During the last two decades, policy makers have

increasingly recognized that water quality is

adversely affected by sediment-laden

stormwater discharge from construction sites.

On December 1, 2009, the U.S. Environmental

Protection Agency (EPA) published a rule in the

Federal Register establishing non-numeric and,

for the first time, numeric effluent limitation

guidelines (ELGs). The numeric ELGs included a

turbidity limit of 280 nephelometric turbidity

units (NTUs) and sampling requirements for

stormwater discharges from construction sites

that disturb 20 or more acres of land at one time.

EPA’s decision to regulate turbidity through a

numeric standard was based on the agency’s

conclusion that turbidity is an “indicator

pollutant” for identifying other pollutants

flowing from construction sites. Following

litigation in April 2013, EPA proposed to

withdraw the numeric ELG requirement, at least

for the time being. However, some future

numeric limits are anticipated in the near future.

US Transportation Collection