What is an MS4?
A Municipal Separate Storm Sewer System (MS4) is defined by EPA as “a conveyance or system of conveyances owned or operated by a public body designed for collecting or conveying stormwater.” MS4s include municipalities of cities, states, and federal systems such as military bases and correctional facilities.
In December 2018, the United States Environmental Protection Agency (US EPA) issued an MS4 permit for Naval Base Guam (NBG). This permit became effective January 1, 2019 and it is one of several that NBG must comply with under the National Pollutant Discharge Elimination System (NPDES). The MS4 NPDES program was developed to reduce and eliminate the release of toxic substances in storm water runoff into downstream water bodies.
NBG has developed the Storm Water Management Program (SMWP) to comply with the new permit requirements. The SWMP is designed to reduce the discharge of pollutants from the MS4 to the maximum extent practicable using Best Management Practices (BMPs). The SWMP consists of six minimum control measures (MCM) for storm water management, which include:
1. Public education and outreach through multi-media platforms
2. Public involvement and participation through community engagements
3. Illicit discharge inspection, detection, education, and elimination
4. Construction site storm water runoff control through erosion and sediment control, inspections of construction sites and response to public complaint.
5. Post-construction and green infrastructure storm water management in new development and redevelopment through inventories, mapping, inspections and maintenance
6. Pollution prevention and good housekeeping through inventories, mapping, inspections, maintenance, street sweeping, employee training and waste disposal
For each MCM, measurable goals have been developed, which allows US EPA to monitor permit compliance.
NBG’s MS4 SWMP and annual reports is required to be made available to the public under the MCM 2 in Section 2 of the MS4 Permit.
Any comment or question regarding NBG’s stormwater program may be directed to NBG’s Stormwater Program manager at (671) 339-3711.
NBG MS4 Permit & Stormwater Management Plan
MS4 Annual Reports
Flyers & Handouts
Construction Sites Stormwater Quality