General Plan Update - City of Inglewood

3.3 Storm Drains
NPDES Permit Program—Phase II
On August 7, 1995, EPA amended the NPDES permit application requirements in order
to focus on Phase II storm water discharges, such as discharges caused by the following:
• Commercial, light industrial and institutional activities
• Construction activities under 5 acres
• Municipal storm drain systems serving populations under 100,000
Similar to Phase I requirements, the NPDES Phase II permit program also requires the
development and implementation of storm water management plans to reduce such
discharges. Affected agencies must apply for a NPDES Phase II permit by March 2003.
General Construction Storm Water Permit
Construction site storm water management is governed by the State Board under Water
Quality Order 99-08-DWQ/NPDES General Permit No. CAS000002. These regulations
prohibit discharges of storm water to waters of the United States from construction
projects that encompass one or more acres of soil disturbance unless the discharge is in
compliance with an NPDES permit. The California General Permit (enforced by the nine
Regional Boards) requires all dischargers where construction activity disturbs one acre or
more to do the following:
• Develop and implement a SWPPP that specifies BMPs that will prevent all
construction pollutants from contacting storm water and with the intent of keeping
all products of erosion from moving off site into receiving waters
• Eliminate or reduce non-storm water discharges to storm sewer systems and other
waters of the nation
• Perform inspections of all BMPs
Los Angeles County requires an Erosion Control Plan (ECP) for all developments as part
of the SWPP; if development is less than one acre, only an ECP is prepared.
Construction activity subject to this General Permit includes clearing, grading,
disturbances to the ground such as stockpiling, or excavation that results in soil
disturbances of at least one acre of total land area. Construction activity that disturbs less
than one acre of soil is subject to this General Permit if the construction activity is part of
a larger common development plan (encompassing one or more acres of disturbed soil)
or if the construction causes significant impairment to local water quality. Construction
activity does not include routine maintenance to maintain original line and grade,
hydraulic capacity, or original purpose of the facility, nor does it include emergency
construction activities required to protect public health and safety. A construction project
that involves a dredge and/or fill discharge to any jurisdictional surface water (e.g.,
wetland, channel, pond, or marine water) also needs a CWA Section 404 permit from the
U.S. Army Corps of Engineers and a CWA Section 401 Water Quality Certification from
the Regional Board and State Board. Storm water discharges from dredge spoil
placement, which occur outside of Corps jurisdiction (upland sites), and are part of
City of Inglewood General Plan Update Technical Background Report
3.3-5