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<br />Final Storm Water
<br />Phase /I Rules
<br />Approved
<br />(continued)
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<br />OOlG46
<br />Permitting Program Elements
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<br />Under the NPDES regulations, an MS4 is defined as "a conveyance or system of conveyances
<br />(including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches,
<br />man-made channels, or storm drains)" owned or operated by federal, state, local, or tribal
<br />governments. In practical terms, operators of MS4s include municipalities and local sewer
<br />districts, state and federal departments of transponation, universities, hospitals, military bases, and
<br />correctional facilities. These regulated entities must obtain an NPDES storm water permit and
<br />implement pollution prevention plans or management programs specifying BMPs that minimize
<br />or prevent the discharge of pollutants into receiving waters.
<br />
<br />The panicular permit options (individual or general permit) available are subject to the discretion
<br />of the NPDES permitting authorities operating in 43 states and the Virgin Islands. EPA estimates
<br />that MS4s in 3,700 incorporated jurisdictions and 97,000 construction sites would be subject to
<br />regulation in delegated states and territories, with an additional 405 MS4s and 19,000
<br />construction sites regulated directly by EPA in nondelegated jurisdictions (Idaho, New Mexico,
<br />Arizona, Alaska, Maine, New Hampshire, Massachusetts, and Puerto Rico).
<br />
<br />To facilitate the coordinated development and management of suburban storm water programs,
<br />the new Phase II Rule would allow owners/operators of small MS4s to merge their programs with
<br />those of adjacent MS4s in cities or other urbanized areas. Jurisdictions wishing to merge their
<br />programs with adjacent permitted programs would join as co-permittees upon agreement by all
<br />involved parties. Each entity in the consonium would be subject to the permit requirements, but
<br />the cooperative, coordinated approach would reduce permit application and reponing tasks and
<br />characterization requirements, and make their performance more efficient. The co-permitting
<br />provision will provide an attractive option to urban fringe areas, suburban municipalities, and
<br />counties, some of which may be split into regulated and unregulated zones under the Phase II
<br />program. A whole county will be included in the Phase II program only if all its census blocks
<br />meet the urbanized area definition (i.e., densities greater than 1,000 per square mile). If pan of a
<br />county meets the designation and pan does not, only the urbanized part must be included in the
<br />program. The same stipulation holds for Indian lands and U.S. territories.
<br />
<br />Permits must outline minimum control measures designed to reduce pollutant discharges to the
<br />maximum extent practicable and to protect water quality. EPA considers narrative effluent
<br />limitations (e.g., no floatables, no visible sheen) and provisions requiring implementation ofBMPs
<br />vital permit components, according to the Federal Register notice published in early December.
<br />Control measures include, at a minimum, public education and outreach, public
<br />involvement/panicipation, illicit discharge detection and elimination, construction site storm
<br />water runoff control, postconstruction storm water management in new development and
<br />redevelopment, and pollution prevention/good housekeeping for municipal operations.
<br />
<br />The Construction Industry and Phase 1/
<br />
<br />Phase II targeted construction sites because they significantly impact water quality. Research over
<br />the past three decades has found that erosion rates from construction sites are an order of magni-
<br />tude higher than those measured on row croplands and several orders of magnitude higher than
<br />erosion rates on well-vegetated lands. Soil loss from new development can range from 20 to 150
<br />tons per acre, per year; the national average for soil erosion from cropland is about 8 tons per year.
<br />
<br />A 1997 study conducted by the Virginia Water Resources Research Center revealed that
<br />sedimentation of streams and rivers from road construction in Northern Virginia reduced aquatic
<br />insect and fish communities by up to 85 and 40 percent, respectively. Other research in the
<br />Patuxent River basin found that 3 to 3.5 miles of stream reaches below construction sites were
<br />adversely affected by construction-related sediment loading. Siltation is the second leading cause
<br />of impaired water quality in rivers and lakes nationally.
<br />
<br />The Phase II Rule requires operators of regulated construction sites where more than one acre is
<br />disturbed to obtain an NPDES permit and implement management practices to minimize
<br />pollutant runoff, including erosion. NPDES permitting authorities will likely use their existing
<br />storm water general permit programs as the operating framework for Phase II programs. For the
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<br />NONPOINT SOURCE NEWS-NOTES
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<br />MARCH 2000, ISSUE.60
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