Olympic National Park Seeks Public Input Regarding Proposed Port Angeles Stormwater Separation Project

In collaboration with the City of Port Angeles, the Olympic National Park is inviting initial public input on the Port Angeles Stormwater Separation Project, a component project of Elwha Restoration. Input will be used to help develop an environmental assessment about the proposed project.

The proposed project is part of mitigation proposed by the National Park Service (NPS) to protect the Lower Elwha Klallam Tribe community from impacts of removing the two dams on the Elwha River. After the dams are removed, additional sediment will be carried downstream by the river, leading to higher stream flows and higher groundwater in the river’s flood plains, which include areas within the Lower Elwha Klallam reservation. In turn, higher groundwater will increase the risk of septic system failures on the reservation.

To protect the tribal community from this increased risk and provide for continued collection and treatment of the community’s wastewater, the NPS is constructing a wastewater collection system for the reservation. In collaboration with the City of Port Angeles, the collected wastewater will then be treated and discharged to the City’s existing wastewater treatment plant.

To protect the City’s wastewater system from impacts associated with increased wastewater flows, the NPS is proposing a stormwater separation project.

The proposed project would collect stormwater from impervious surfaces in a four-block area of downtown Port Angeles and keep it separate from household wastewater and sewage. Currently, stormwater from this area is added to the City’s combined sewers and is treated by the wastewater treatment plant. The proposed project involves construction of a new storm drain which would collect stormwater from this area, and add it to an existing storm drain system along Valley Street which discharges Valley Creek into Port Angeles Harbor.

The project includes construction of approximately 1,750 lineal feet of buried 18-inch diameter storm pipe on First Street from Laurel to Valley Street and a connection to the existing storm drain in Valley Street. All construction would occur within existing City streets.

The project would result in an increase in Valley Creek flows of approximately 1 to 3 percent during 1-year storm events and less than 1 percent during 25-year storm events. A water quality treatment unit will be included that will provide levels of treatment consistent with state stormwater regulations.

Since the project is part of mitigation for dam removal, the stormwater separation project will be funded by NPS.

An Environmental Assessment (EA) is being prepared to evaluate the environmental effects of this proposal. Interested members of the public are invited to provide input on the proposed project. Comments received during this initial scoping period will be used to help define the issues and concerns to be addressed in the EA.

Public comment will be accepted through May 3, 2010 and may be submitted online by selecting Olympic National Park at the NPS Planning, Environment and Public Comment website, http://parkplanning.nps.gov, or sent to:

Superintendent
Port Angeles Stormwater Separation Project
Olympic National Park
600 East Park Avenue Port Angeles, WA
98362