Hood Canal

Hood Canal
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Introduction

Hood Canal's worsening problem of low dissolved oxygen is the basis for ongoing scientific study of this fjord-like arm of Puget Sound. Although the waters of Hood Canal are pristine to the naked eye, the canal has a history of naturally occurring low dissolved oxygen (DO) levels. This is due to the canal's long, narrow shape with an entrance sill on the northern end resulting in areas of stagnant, layered waters that resist mixing by tides and winds (PSAT, 2004). Unique bathymetric features of the canal result in low flushing and water exchange (Hood Canal Dissolved Oxygen Program 2005). The canal has an entrance sill that is only 45.7m deep proximal to a 152-182m entrance depth. This makes it difficult for run-off polluted waters to dilute and flush. In dry years, dissolved oxygen levels in Hood Canal become lethal to aquatic life(Hood Canal Dissolved Oxygen Program 2005). The Hood Canal Watershed has nearly
54,000 residents with nearly 24,800 onsite septic systems, and there is no measure to date of sewage generated by public buildings (Hood Canal Action Team 2005). Onsite sewage systems are estimated to contribute between 39 and 241 tons of nitrogen into Hood Canal. The town of Belfair, although located on Hood Canal has no wastewater treatment facilities as of yet (Puget Sound Online 2005). The purpose of this survey was to document vertical water column properties (temperature, salinity, and density), plankton distributions, nutrient distribution, and dissolved oxygen concentrations. It was expected that evidence of stratification would be seen in measurements of temperature, salinity, and density. The inner reaches of the canal, from the Great Bend to Lynch Cove were expected to yield decreasing measurements of dissolved oxygen and salinity. This field report also compares dissolved oxygen data collected in Hood Canal in 2005 to historical dissolved oxygen collected by the Department of Ecology in previous years.









Acknowledgements


We would like to thank Dave Thorsen from the College of Ocean and Fishery Sciences and Rene Rose from the Hood Canal Salmon Enhancement Group for providing boats, eqipment and technical support.
We would also like to thank Dr. Cheryl Greengrove from the University of Washington Tacoma Interdiscliplinary Arts and Sciences Environmental Science Department for her exemplary leadership and guidance.


[TESC 431 Home ] [Introduction] [Sampling Stations/HC Methods] [Methods] [Results/Discussion] [Data Repository] [References]

Created by Jeff Hubert and Lee Ann Acker