How to take off erosion control from a SWPPP sheet
Taking off silt fence, inlet protection, construction entrances, matting and basins from an erosion control plan, including maintenance and phasing quantities.
6 min read
Key takeaways
- Erosion control is measured in LF, EA, SY and disturbed acres all at once.
- Phased plans repeat measures — read initial, interim and final sheets separately.
- Maintenance and removal are real line items, not overhead.
- Disturbed acreage should match the earthwork takeoff.
Erosion control looks like the cheapest sheet in the set and regularly becomes one of the most expensive scopes, because it is installed, maintained, moved and reinstalled over the life of the job. A takeoff that captures only the first installation misses most of the money.
Measure the perimeter and the point measures
| Measure | Unit | How to take it off |
|---|---|---|
| Silt fence | LF | Trace along the alignment shown, including returns |
| Inlet protection | EA | Count by inlet type; verify against the storm structure count |
| Construction entrance | EA or SY | Count locations; measure pad area for stone |
| Erosion control matting / blanket | SY | Area of slopes and channels shown |
| Rock check dams | EA | Count in channels and swales |
| Sediment basin / trap | EA plus CY | Count, then excavation volume from the detail |
| Disturbed area | AC | Area within the limits of disturbance |
Read the phasing, then multiply
Most SWPPP sets include initial, interim and final phase sheets. Measures often appear on more than one — a silt fence line may be installed in phase one, relocated in phase two, and removed at stabilization. Take off each phase as its own set of quantities, then decide which items are new installs and which are relocations.
- Take off the initial phase completely.
- Take off each later phase, marking items that are new versus carried forward.
- Add relocation quantities where a measure moves.
- Add removal and final stabilization quantities.
Inlet protection is installed on structures that must already exist. If storm is built in phase two, inlet protection cannot be a phase-one quantity — a mismatch here is a good sign you have read the phasing correctly.
Do not forget maintenance and inspection
- Routine inspections, typically weekly and after qualifying rain events.
- Sediment removal from traps, basins and behind silt fence.
- Repair and replacement of damaged fence and matting.
- Street sweeping and tracking control.
- Dust control, including water trucks.
- Concrete washout facilities and their maintenance.
Stabilization is a takeoff too
Temporary and permanent stabilization quantities come off the same disturbed area you computed for earthwork: temporary seeding on areas idle beyond the specified window, permanent seed and mulch, sod in specified locations, and topsoil respread depth. Because these are area-based, an inconsistency between your grading and erosion control areas is worth resolving before you price either.
Cross-check against the other sheets
- Disturbed acreage should match the limits of disturbance used in the earthwork takeoff.
- Inlet protection count should match the storm structure count for structures in the disturbed area.
- Matting area should correspond to slopes steeper than the threshold in the notes.
- Silt fence should enclose the downhill perimeter — gaps usually mean you missed a sheet.
Doing this work in TakeoffAI? Length and area tools.
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