King County in partnership to learn more about health of Vashon’s Quartermaster Harbor

A long-term research partnership has been formed to get to the bottom of Quartermaster Harbor’s troubling low dissolved oxygen levels. The results of this study will help determine the causes of the problem and identify potential solutions.

King County, in partnership with the Environmental Protection Agency, the University of Washington-Tacoma, Washington State Department of Ecology and the Vashon-Maury Island Groundwater Protection Committee is conducting a four-year study to evaluate the role of nitrogen in the risk of lethal, low-level dissolved oxygen events in Quartermaster Harbor.

Low dissolved oxygen levels can kill marine life, such as fish, shellfish and other marine organisms.

There will be a public presentation about the Quartermaster Harbor nitrogen loading study at 7 p.m. on Thursday, Nov. 19 at the Vashon Maury Island Land Trust, 10014 Bank Road SW, Vashon.

Dissolved oxygen levels in Quartermaster Harbor have been recorded near lethal levels over the past three years of monthly monitoring. As a poorly flushed embayment of Puget Sound, Quartermaster Harbor has many characteristics similar to Hood Canal, where multiple, lethal, low-oxygen events have occurred.

Quartermaster Harbor has similarities to Hood Canal, including increased upland development, high value shellfish fisheries, and high value ecological habitat.

Laurence Stockton, King County’s Groundwater Protection Program Manager, said the study will include identifying and quantifying nitrogen sources, plus modeling what impacts nitrogen is having on dissolved oxygen in Quartermaster Harbor.

“The expected outcomes of this study are a better understanding of the nitrogen loading entering Quartermaster Harbor, the impact of nitrogen loading on the observed low dissolved oxygen events, and recommendations for policy changes to improve nitrogen management on Vashon-Maury Island,” Stockton said.

The policy recommendations will be transferable to similar rural areas in Puget Sound where inputs of nitrogen from small streams, on-site septic systems and direct groundwater discharge flow are impacting the receiving marine waters, Stockton said.

The Quartermaster Harbor Nitrogen Management Study will be conducted in three phases starting in 2009 and working through 2012:

• Phase one will estimate the nitrogen loadings from various potential sources using existing data and published literature values and by preliminary water quality sampling of streams, groundwater and marine waters;
• Phase two will build upon the results of the phase-one work by collecting additional data, modeling the contributing nitrogen loadings in to Quartermaster Harbor, and developing a hydrodynamic model of Quartermaster Harbor to simulate water conditions.
• Phase three will link the nitrogen loadings to Quartermaster Harbor dissolved oxygen levels by simulating the effects of different nitrogen management scenarios there.

The cost of the study is estimated at $893,000; of that amount, $625,000 is being provided by a grant from the Environmental Protection Agency, with the remaining funding coming from King County, the University of Washington-Tacoma and the state Department of Ecology.

New policy recommendations for nitrogen management on Vashon-Maury Island will be developed working with stakeholders for consideration in the next update of the King County Comprehensive Plan, which is scheduled for 2012.

Extensive surface, ground and marine water data are being collected as part of this project. The data, documents and reports for the project are available at: http://www.kingcounty.gov/environment/watersheds/central-puget-sound/vashon-maury-island/quartermaster-nitrogen-study.aspx.

For more information about the Quartermaster Harbor nitrogen loading study or to request a presentation concerning the study, contact Stockton at 206-296-1910 or laurence.stockton@kingcounty.gov.

Related information

Vashon - Maury Island environment

Puget Sound marine topics

King County Water and Land Resources