Stormwater Separation to Mitigate Lower Elwha Flows to City of Port Angeles
In collaboration with the City of Port Angeles, the Olympic National Park is inviting the public to review and comment on the Port Angeles Stormwater Separation Project, a component project of Elwha Restoration.
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.
Adding the collected wastewater to the City's sewer system would put additional pressure on the City's combined sewer system, and would contribute to increased combined sewer overflow (CSO) discharges. Under an Agreed Order with Washington Department of Ecology, the City is not permitted to take any actions that increase the number or quantity of untreated (CSO) discharges. To protect the City's wastewater system from impacts associated with increased wastewater flows, the NPS is proposing the stormwater separation project.
Since the project is part of mitigation for dam removal, the stormwater separation project will be funded by the NPS.
The preferred alternative proposes to collect stormwater from impervious surfaces in a four-block area of downtown Port Angeles and keep it separate from household wastewater and sewage. 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. All construction would occur within existing City streets.
Comments will be accepted through November 10, 2010. The National Park Service encourages public participation through the NEPA process. After the public review period, the comments received will be carefully considered before a decision is made regarding implementation of actions proposed in the Port Angeles Stormwater Separation EA. Commenters should be aware that their comments, including names and home addresses, are considered public information and may be released to the public. However, individual commenters may request that their name and home address be withheld from public release by stating this in their comment letter.
Olympic National Park
600 East Park Avenue
Port Angeles, WA 98362