Craven Street Stormwater Control Measures

Tropical Storm Helene damaged stormwater infrastructure across western North Carolina. Under FEMA Public Assistance, recovery funding for large projects depends on cost documentation meeting the Cost Estimating Format, a structured standard requiring scope, quantities, and pricing to be defensible line by line rather than asserted in a lump sum.

The five Craven Street stormwater facilities comprise four different SCM types, each regulated under a different North Carolina Minimum Design Criteria rule. Permeable pavement, a bioretention cell, a vegetated swale, and a stormwater wetland do not fail the same way, do not get repaired the same way, and do not share a regulatory basis. Several repair items had no catalog price. Sediment removal quantities had to be derived rather than assumed, and required materials do not appear in standard cost databases as a single unit price.

Further, FEMA Public Assistance can fund hazard mitigation that reduces the risk of the same damage recurring, but only where the mitigation is shown to be cost effective against the damage it prevents. That determination requires the repair cost documentation to be solid first, because the mitigation case is built on top of it.

RiskHydro built each facility’s CEF as a standalone package following the FEMA CEF Instructional Guide, with repair scope developed facility by facility rather than templated across the group. Pricing came from RSMeans data localized to Asheville, supplemented by supplier and vendor quotes where no catalog line existed. Non-standard items were built up from their components rather than estimated as a whole. That makes each figure auditable and each assumption visible. Quantities were documented on a dedicated basis so each one traces to a measurement, a conversion, or a stated assumption. For the bioretention cell and the stormwater wetland, RiskHydro developed the hazard mitigation case and demonstrated cost effectiveness.

Key tasks included:

• Developed Large Project CEF documentation for five SCMs under Disaster Declaration DR-4827-NC
• Built repair scope facility by facility across four SCM types: permeable pavement, bioretention, vegetated swale, and stormwater wetland
• Verified that each facility’s Minimum Design Criteria citations matched its own SCM type, with cross-citation actively prevented
• Priced work from RSMeans Data Online localized to Asheville, supplemented by supplier and vendor quotes
• Built component-level cost buildups for non-catalog items rather than lump-sum estimates
• Documented quantity derivations and unit conversions on a dedicated basis tab
• Developed hazard mitigation scope and demonstrated cost effectiveness for the bioretention cell and the stormwater wetland
• Produced workbooks programmatically for consistent structure across facilities and controlled revision

For the bioretention cell and the stormwater wetland, RiskHydro established that hazard mitigation was cost effective, which is the difference between rebuilding what the storm damaged and rebuilding something less likely to be damaged again. Across all five facilities, the documentation was built to carry its own weight through review and closeout.

• Hazard mitigation demonstrated cost effective for two facilities, supporting improvements to the bioretention cell and the stormwater wetland that reduce the risk of the same damage recurring, rather than a rebuild to pre-disaster condition
• Five facilities documented to a single standard, so reviewers see the same structure, the same quantity basis, and the same level of support across four different SCM types
• Every line traceable to a basis, with quantity derivations and pricing sources documented rather than asserted, which is what makes cost documentation survive review and closeout
• Component-level buildups for non-catalog items, giving the City defensible pricing for repair scope that standard cost databases do not cover