Over the past several years the State of Hawaii Department of Transportation, Highways Division (DOT-HWYS) has continued to design and construct permanent storm water treatment best management practices (PBMPs) as part of their Post-Construction Storm Water Management Program, Action Plan for Retrofitting Structural BMPs, and Trash Reduction Plan. As of the summer of 2018 there are over 100 PBMPs actively treating storm water runoff throughout DOT-HWYS Municipal Separate Storm Sewer System (MS4); and there are many more in the planning and design phases. These PBMPs include surface grass swales, sediment basins, storm drain screen guards and basket inserts, and large underground vaults with multi-stage treatment and filter systems. However, getting these devices constructed and installed in the MS4 is only the first step. In order for these PBMP devices to function properly and continue to treat storm water runoff they must be regularly inspected, cleaned, and maintained. DOT-HWYS uses an automated database to track the locations and operational status of all PBMPs in the MS4. PBMPs are thoroughly inspected on regular basis and are cleaned and maintained, as necessary, to ensure that they are functioning properly at all times. Ongoing PBMP tracking and maintenance is just one more way that DOT-HWYS continues their commitment to protect our water.

PBMP-Maintenance-1Underground storm water treatment system in Kaneohe being inspected to assess maintenance needs.
PBMP-Maintenance-2Underground storm water treatment system in Ewa being cleaned out using a vacuum truck.
PBMP-Maintenance-3Underground storm water treatment system in Kaneohe prior to cleaning and maintenance.
Underground storm water treatment system in Kaneohe after cleaning and maintenance.