Any development that impacts an area of one acre or more must meet state stormwater requirements and be covered under a NPDES Permit for Discharges Associated with Construction Activities.
NPDES Permits
Whenever "development" takes place—whether we're creating a residential community, office park, or agricultural complex—we’re altering the landscape and affecting the natural water cycle. In order to meet the CWA’s anti-degradation requirements, development efforts should result in no-net-change in stormwater regimes. In other words, runoff volume, rate, and quality should be the same on project completion as it was at the start.
The Phase I National Pollutant Discharge Elimination System (NPDES) discharge program required all operators of large construction activities which will disturb five or more acres of land to obtain permit coverage. More recently, NPDES Phase II regulations added permit coverage for small construction activities that disturb one to less than five acres. Effective December 7, 2002, DEP integrated the federal Phase II NPDES requirements into the existing Pennsylvania Phase I NPDES permit for stormwater discharges associated with construction activities (NPDES Construction Permit). An important distinction between Phase I and II is that the small construction activities only require permit coverage when the activity disturbs one to less than five acres and will result in a point source discharge to surface waters of the Commonwealth.
Most construction-related NPDES permits are administered by County Conservation Districts through delegation agreements with DEP. Conservation districts process and authorize the permit applications, conduct site inspections, respond to complaints, and in certain circumstances, conduct enforcement actions.
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How Does This Affect You?
All construction projects that disturb 1 acre or more of land and result in a stormwater discharge must have either an individual stormwater permit, or coverage under one of Pennsylvania's general permits. Operators of sites disturbing less than one acre must also obtain a permit if their activity is part of a larger development with a planned disturbance of one acre or more. For permitting purposes, disturbance includes, but is not limited to soil disturbance, clearing, grading, and excavation.
An application for an individual permit or for coverage under the statewide general permit must be made prior to starting any construction activities, so check with your conservation district and DEP well in advance. Be sure to keep in mind that in addition to the abiding by the permit, you will also be subject to local stormwater and erosion control regulations.
To ensure that all bases are covered developers need to think about stormwater management at the earliest stages of project conceptualization. Project teams (owner/developer, consultant/designer, contractor) are encouraged to meet with regulators (local government, county conservation district and DEP regional office) to discuss and review preliminary plans.