Projects > Quartermaster Harbor Nutrient Mitigation Project

Quartermaster Harbor on Vashon Island is a shallow, circulation-restricted bay with development along its shoreline and within the watershed. The  water circulation of the bay combined with a suite of waste and stormwater inputs, has led to low oxygen conditions in the inner harbor.  This indicates a eutrophic marine system, which alters habitat and species diversity and reduces estuary function. These same inputs from the watershed have caused the Department of Health to close most of the harbor to shellfish harvest.

The time is ripe for developing community-based solutions to waste and stormwater issues.   This project provides a focal point for discussing and developing one possible strategy using the ecosystem services of bivalve shellfish. The idea is to develop a creative strategy for mitigating chronic nutrient loads in Quartermaster Harbor while also engaging Vashon residents in the recovery of healthy marine resources. Additionally, this project seeks to develop market-based mechanisms for cleaning Puget Sound that are potentially transferable to other local embayments.

PSRF is in the process of implementing a project, funded in part by a King County WaterWorks grant, that includes a field demonstration of bivalve mariculture that could provide a cost-effective and feasible means of mitigating nitrogen inputs in Quartermaster Harbor.  This strategy has been successfully demonstrated elsewhere in the world.  We plan to install an experimental field station in Quartermaster Harbor where we will culture native mussels.  The station itself is a small raft, specially designed to allow for careful measurements during the trial.  These will include assessments of nutrient removal and ecosystem services of the cultured shellfish.  With the timely removal of grown mussels, we will evaluate market-based mechanisms to redistribute the sequestered nutrients back into the watershed.

The raft-based field demonstration will be located in Quartermaster Harbor’s inner harbor, secured to a specialized mooring designed to anchor the raft.  The raft will be 8 x 30 feet.  Instrumentation will be mounted on the raft to measure water motion and quality during the trial, in addition to onsite water samples.  Onsite data collection and biomass samples will be analyzed to quantify a suite of ecosystem services and nutrient sequestration by the mussels and associated marine biomass.  Once the shellfish are grown, they will be removed to implement trials of two disposal options that have been examined and have been successful elsewhere in the world.  They are:

• Composting of mussels to create a value-added soil amendment.
• Processing of mussels to create an animal feed additive.

Currently, the project is in the permitting phase and PSRF anticipates beginning the bioassay in April 2011.  Completion of the 18-month project will also develop the conceptual model for a nitrogen trading system that could potentially be applied to other parts of Puget Sound.  The project will actively involve the Vashon Island community in various aspects of the project and conduct public outreach to increase awareness of the causes and effects of excess nutrients.  We will be contacting Vashon Island schools, community groups, nurseries, growers associations, shoreline property owners and other stakeholders to discuss this project and how people can get involved in the health of Quartermaster Harbor.  If you or someone you know would like to get involved in this 2010 effort, please contact PSRF via email or phone (206) 780-6947.  Check out an article on our project in the Vashon Maury Island Beachcomber, at area workshops and conferences and as we conduct focused neighborhood outreach to reduce pet waste runoff.

Let’s get creative and focus on what can be done to turn the tide in Quartermaster Harbor and recover your local marine resource!

Download a schematic of the intended raft placement here.