Using Value-Focused Thinking to Evaluate the Practicality of Porous Pavement Parking Areas on Air Force Installations

Natural runoff processes have been altered by urban development; impervious surfaces (rooftops, highways, parking areas) and their associated stormwater systems channel runoff from a vast area into one concentrated outflow. This stormwater runoffcan cause erosion, flooding, landslides, and significant damage to aquatic ecosystems.Runoff from highways and parking areas has also been shown to contain high levels ofsuspended solids, heavy metals, and hydrocarbons. Porous pavements allow infiltrationof water through typically impervious surfaces, reducing stormwater volumes and actingas a pollutant filtration system.Since there is currently no methodology for Air Force decision-makers tocompare conventional and porous pavements, a model was created using Value-FocusedThinking (VFT) to evaluate different paving options. Four porous paving alternativeswere compared against two conventional paving alternatives at three separate geographiclocations. These alternatives were scored using a total of 12 evaluation measures thatwere identified as important to the pavement selection process. Structural turf, a porousalternative, was found to be the best option for northern tier locations, while conventionalasphalt was the best choice for central and southern areas. VFT was also shown to be aneffective methodology for comparing conventional and porous paving alternatives,objectively weighing economic costs against environmental considerations.