Retrofit Needs Assessment and Whole Life Cost Assessment

Focus Area

Water Quality/Wetlands


Natural Resources




Under $99k


Under 1 year

Research Idea Scope

The US interstate highway system is essentially complete, and was constructed in large part without the benefit of stormwater quality features to improve highway runoff water quality or measures to mitigate increases in runoff rate and volume. Stormwater MS4 NPDES permits for DOTs are beginning to include assessments and programs to retrofit water quality and quantity measures into existing highway infrastructure. DOTs need to understand the potential capital and O&M liability associated with compliance with MS4 NPDES Permit retrofit requirements. The purpose of this synthesis topic is to assess the requirements of DOT stormwater permits nationally (this is available through NCHRP 25-25(56), dated 2010), and develop an estimate of capital improvements required to meet the post-construction permit retrofit requirements. Since permit requirements vary across the US, the selected contractor will develop categories of permit requirements, or a similar approach, and develop estimates for the selected categories (a maximum of 3). The capital cost estimate will be complemented with an estimate of O&M costs for the required infrastructure. Cost information may be obtained from NCHRP 792 for both O&M and capital estimates. The cost information will provide DOTs with basic information needed to plan their stormwater programs over a long-term horizon.

Urgency and Payoff

This research should also consider opportunities for DOTs to partner with traditional municipalities to comply with their permit requirements. The research should assess the potential for shared facilities and cost sharing of infrastructure to defray program capital and O&M costs. The estimates should be based on the least-cost strategies that incorporate local community partnerships as practical. The research should determine if there are federal funding limitations to this type of approach.

Suggested By

Scott Taylor TRB AFB65 7606036242

[email protected]