10.1 Stormwater Plan Types, Credentials, and Authority

Signatory and qualification checks

For the detailed method and approval qualifications, review the related CESSWI explanation.

Comparing the Primary Stormwater Plan Documents

In professional stormwater inspection practice (covered in the CESSWI General Principles Review Manual, Chapter 11, Sections 11.1–11.4), four distinct regulatory documents govern land disturbance, industrial operations, municipal drainage networks, and bulk petroleum storage.

1. Stormwater Pollution Prevention Plan (SWPPP)

A Stormwater Pollution Prevention Plan (SWPPP) is a comprehensive, legally binding, living compliance document required under National Pollutant Discharge Elimination System (NPDES) Construction General Permits (CGP) and Industrial Multi-Sector General Permits (MSGP). Unlike a static set of engineering blueprints, a SWPPP integrates two equally mandatory halves:

• Physical Erosion and Sediment Control (ESC) Drawings and Specifications: Engineered plan sheets, phased site maps, and structural construction details designed to prevent soil detachment and trap suspended sediment before runoff leaves the disturbed footprint.
• Pollution Prevention (P2) and Good Housekeeping Narrative: Written operational protocols governing chemical and material storage, concrete and stucco washout containment, fueling and equipment maintenance, spill prevention and response, dewatering treatment, routine inspection schedules, analytical sampling, signatory certifications, and Corrective Action Logs.

2. Erosion and Sediment Control Plan (ESCP) / Grading and Drainage Plan

An Erosion and Sediment Control Plan (ESCP) (often titled the Grading, Drainage, and Erosion Control Plan in municipal submittals) consists of the civil engineering drawing set, standard detail sheets, and technical specifications focused specifically on physical soil stabilization, runoff conveyance, and sediment trapping during earth-disturbing activities. Local municipalities and county conservation districts frequently require an approved ESCP before issuing a local grading or land-disturbance permit. On sites disturbing $1\text{ acre}$ or more (or smaller parcels within a common plan of development), the approved ESCP serves as the graphical and structural backbone embedded inside the broader NPDES construction SWPPP.

3. Stormwater Management Program / Plan (SWMP)

On the CESSWI examination, the acronym SWMP carries two distinct regulatory definitions depending on the permit context:

1. Municipal MS4 Stormwater Management Program (SWMP): The jurisdiction-wide written compliance document required under NPDES Phase I and Phase II Municipal Separate Storm Sewer System (MS4) permits. It details the ordinances, standard operating procedures, enforcement mechanisms, and measurable goals a city, county, or transportation agency uses to implement the Six Minimum Control Measures (MCMs): (1) Public Education and Outreach, (2) Public Involvement and Participation, (3) Illicit Discharge Detection and Elimination (IDDE), (4) Construction Site Stormwater Runoff Control, (5) Post-Construction Stormwater Management in New Development and Redevelopment, and (6) Pollution Prevention / Good Housekeeping for Municipal Operations.
2. Post-Construction Stormwater Management Plan (SWMP): A site-specific civil engineering design and long-term Operation and Maintenance (O&M) Plan governing permanent post-construction stormwater control measures (such as wet retention ponds, dry extended detention basins, bioretention cells, permeable pavements, and subsurface infiltration vaults) that remain in service permanently after construction terminates.

4. Spill Prevention, Control, and Countermeasure (SPCC) Plan

A Spill Prevention, Control, and Countermeasure (SPCC) Plan is a federal oil pollution prevention document mandated under 40 CFR Part 112 (authorized by Clean Water Act Section 311), rather than an NPDES Section 402 stormwater permit. A construction project, quarry, or industrial facility must prepare and implement a standalone SPCC Plan if a spill could reasonably be expected to discharge oil in harmful quantities into navigable waters or adjoining shorelines AND the site exceeds either of two statutory storage thresholds:

• Aboveground Oil Storage Threshold: Aggregate aboveground oil and petroleum storage capacity exceeding $1,320\text{ gallons}$ (counting only containers with a capacity of $55\text{ gallons}$ or greater, such as $55\text{-gallon}$ drums, double-walled skid tanks, and mobile refueler tankers parked in a stationary staging zone).
• Underground Oil Storage Threshold: Completely buried underground oil storage capacity exceeding $42,000\text{ gallons}$.

An SPCC Plan requires sized secondary containment (capable of holding at least $100\%$ of the volume of the single largest tank inside the dike or berm plus sufficient freeboard—typically $110\%$ total capacity—to contain a 25-year, 24-hour precipitation event) and must be certified by a licensed Professional Engineer (PE) (unless the site qualifies as a smaller Tier I or Tier II facility storing $\le 10,000\text{ gallons}$ in aggregate with no single tank exceeding $5,000\text{ gallons}$ for Tier I, allowing qualified owner self-certification).

Comparison of Primary Stormwater and Spill Compliance Documents

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