Construction Erosion + Sediment Control: silt fence, sediment basin, stabilized entrance, prompt stabilization (NPDES CGP)
EPA Stormwater — Construction-phase Erosion + Sediment ControlDescription
Sites disturbing > 1 acre require an NPDES Construction General Permit + a Stormwater Pollution Prevention Plan (SWPPP). Even smaller residential sites benefit from these practices: silt fence around disturbed areas; stabilized construction entrance (gravel pad ≥ 50 ft); sediment trap or basin for runoff collection; prompt stabilization of disturbed soils within 14 days of grading completion (seed + mulch). Inlet protection (gravel bags or fabric inserts) on storm drains receiving site runoff.
Why this exists
Construction sites discharge orders of magnitude more sediment per acre than developed sites. ESC is the architect's environmental responsibility on every site — and required by federal law on sites > 1 acre. Architects should call out the SWPPP requirements in the bid documents to make sure the contractor budgets for them.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
cgpThreshold | min | 1 | acre disturbed | Construction General Permit threshold |
stabilizationDeadline | max | 14 | days post-grading | Time to stabilize disturbed soils |
Categories
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Exterior ramps: maximum slope 1:12, minimum 36 inch clear width · HUD FHA Design Manual Chapter Two §2.7
- Build to the latest natural-hazard-resistant code edition · FEMA P-2325 §Building Codes Basics
- Coastal-pile foundations should embed deeply to resist erosion + uplift · FEMA P-2325 §Florida Building Code / Sand Palace lessons
- Lowest floor at or above Base Flood Elevation in Special Flood Hazard Areas · FEMA P-2325 §Flood Hazard Provisions
- In WUI zones, protect openings from wind-blown embers · FEMA P-2325 §Wildland-Urban Interface (WUI)
Last reviewed 2026-05-15.