The State of Hawaii Department of Transportation, Highways Division, Oahu District (DOT-HWYS) has numerous roadway construction projects that vary in size and complexity. All construction projects, regardless of size or area of land disturbance, must implement best management practices (BMPs) to control sediment and prevent erosion.

For this quarter, we want to highlight the Freeway Management System, Phase 2 project based out of Lower Halawa Field Office for implementing great stabilization practices to reduce the amount of time disturbed land is susceptible to storm water and has the potential to discharge pollutants into the municipal separate storm sewer system (MS4) and receiving waterbodies. The project scope is the installation of variable message signs (VMS), CCTV cameras, speed readers, and traffic detectors at various locations on O’ahu.

To minimize the amount of time an area of the project is disturbed, due to excavation, the existing vegetation and top soil are stockpiled and covered with plastic until ready to backfill. Preserving the root system of the existing vegetation allows for immediate stabilization and drastically reduces the potential to pollute.

Phasing construction activity and immediately initiating temporary or permanent stabilization is one of the best BMPs for sediment and erosion control.