Impact of Alternative Stormwater Management Practices on Highway Infrastructure

John Nieber, Professor
Robert Sykes, Associate Professor, Landscape Architecture
Caleb Arika, Research Associate

Funding Source

Local Road Research Board

Objective

To assess the cost impact that alternative stormwater management practices have on public utilities and to assess the acceptability of alternative stormwater management practices among public officials, contractors, and landowners.

Need or Impact

Alternative stormwater management practices are becoming popular because of the need to better control the quantity and quality of surface runoff. One common alternative stormwater management practice is the use of infiltration features such as rain gardens, dry swales, and dry ponds. There is a perceived concern among public utilities personnel that the adoption of these practices could lead to increased cost of utility infrastructures due to the need for more frequent maintenance.

Project Status

Twenty-five sites with best management stormwater practices using infiltration have been located in the Twin Cities metro area, and these have been characterized with respect to size, runoff contributing area, soil type, relative location to nearest roadway infrastructure, and infiltration capacity. Data from these sites will be evaluated to assess how well the stormwater practices are working relative to design guidelines. The potential for infiltrating water to enter into the base and subgrade material of the nearby roadway will be evaluated, and the potential for damage to the roadway will be assessed with a pavement design tool. The condition of the roadways near these stormwater practices will also be evaluated with a pavement condition index. Additional work on this project will involve estimating costs for maintenance of the BMPs and the associated increase (if any) in cost to maintenance of the nearby roadways as a result of the presence of the stormwater practice. The final report will provide guidelines to practitioners for selecting BMP stormwater practices for use near roadway infrastructure.