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Maritime Stormwater Tenant Information

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Most tenants are responsible for maintaining stormwater structures within their leasehold. These structures include ditches, sanitary sewer connections, floor drains, channels, pipelines, conduits, roads or streets, curbs, gutters, storm drains, French drains, catch basins and manholes that may have inserts to collect oil and grease. Port staff can assist tenants with maintenance or repairs to these structures. To request or report issues please contact your Port property manager. Your lease and preferential use language can also be helpful in understanding your requirements. If you have additional questions regarding operation and maintenance practices please contact your property manager.

Municipal Permit - Tenant Responsibility for Illicit Discharge Detection and Elimination (IDDE)

Tenants are responsible for eliminating any non-stormwater connections to the storm drainage system and should take care not to dump or discharge any substance (other than rainwater runoff) into the stormwater system. Any non-stormwater discharge into the stormwater system is considered an illicit discharge and is prohibited under the Port's Illicit Discharge Policy.

Illicit Discharge Detection and Elimination (IDDE)

The Maritime Port's Illicit Detection and Discharge Elimination (IDDE) program concentrates on the prevention, detection and removal of illicit connections and discharges, including spills, into the Port-maintained stormwater system. The goal is to prevent anything other than clean rain water from entering the stormwater system and eventually draining to Puget Sound.

The IDDE program contains several components:

  • An adopted policy prohibiting illicit discharges
  • An enforcement plan with mechanisms for ensuring compliance An ongoing effort to create an electronic map of all outfall locations, land use, storm drain pipes and structures
  • A program to document operation and maintenance records for stormwater facilities
  • Field inspections of outfalls and stormwater structures to identify and remove illicit discharges
  • A spill response plan with a qualified spill responder

The Maritime Port works with tenants to avoid spills and non-stormwater discharges to the stormwater system. In the event of an accidental spill, follow the Environmental Incident Notification Guidelines to report the spill or discharge.

Municipal Permit - Source Control and Stormwater Pollution Prevention Plans (SWPPPs)

Tenants who hold an Ecology NPDES permit are required to have a Stormwater Pollution Prevention Plan (SWPPP) as part of their permit. This includes Industrial, Boatyard, Construction, and Individual NPDES permits.

For tenants covered under the Port's Phase I Municipal Permit, the Port provides a template to assist in developing a SWPPP for their leasehold. This SWPPP template not only helps tenants to easily create a SWPPP, but it also provides an easy reference for the Best Management Practices required of ALL businesses in the City of Seattle. The SWPPP must include structural and operational mechanisms to protect water quality. Structural mechanisms include installing covers over storage areas and shut-off valves around fueling areas. Operational controls include sweeping debris and pollutants away from the stormwater system and maintaining spill response supplies in clearly marked areas.

Municipal Permit - Construction Projects

New development and re-development projects on Port property must adhere to strict standards to protect water quality. When performing construction projects on Port property, tenants are required to notify their property manager. In addition, tenants must acquire any state or local permits and meet all requirements for projects under their control. Please contact your property manager or refer to your lease and preferential use language for additional information.

If your construction project will disturb more than one acre, you must apply for a Construction Stormwater General Permit from the Department of Ecology and develop an appropriate erosion and sediment control plan to protect downstream water quality. All tenants are required to obtain their own construction permits and meet all requirements of those permits during the construction process. City Code is triggered at 750 square feet of land disturbing activity and tenants should review this before beginning any project. In addition, requirements outlined in the City of Seattle Stormwater Manual must be met by tenant projects.

Tenants are encouraged to consider low impact development (LID) alternatives when designing new projects. LID is a stormwater management strategy that emphasizes conservation and existing, natural site features to more closely mimic natural rainwater runoff patterns. The success of LID strategies, such as permeable paving, vegetated roofs, and rainwater collection systems, is highly dependent on local conditions. Tenants should work closely with the Maritime Stormwater Team and their designing engineer to determine if LID alternatives are feasible on their site.

If you have additional questions regarding construction projects or the Construction Stormwater General Permit please refer to your lease or contact your property manager.

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