Treating stormwater at the roadside is currently not proving cost effective for the Victorian state road authority on major greenfields road projects, however other smaller more urbanised sites such as road duplication projects are proving to be cost effective. VicRoads are currently undertaking research and development programs to ensure treating stormwater at the roadside (know within the industry as water sensitive road design, WSRD) is cost effective across all situations. The construction of exotic grass swales (with limited sections of planted bio-retention system where required for advanced treatment) is proving the preferred and least costly application of WSRD for VicRoads. Grass swales are the most practicable in their application to the linear form of road reservations, require the least amount of ongoing maintenance, and require maintenance practices in line with current roadside landscape practices. Wetlands, sedimentation ponds, sand filters and gross pollutant traps by contrast, prove to have very high construction and ongoing maintenance costs, require specialised maintenance practices, provide no greater pollutant removal capacity, and could pose a greater risk to receiving waters if not properly maintained in the future. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Samenvatting