Red tide on the rise
July 4, 2008 · Updated 10:59 AM
A pink stain appeared on the surface of the Port Washington Narrows Tuesday, March 12, and with the help of the incoming tide began spreading into Dyes Inlet toward Rocky Point and Tracyton.
The red tide was caused by Rhodamine WT, a dye injected into the all-new East Side Wetweather Treatment facility operated by the Bremerton Public Works Department.
Using a model created by the Navys Space and Naval Warfare Systems Center (SPAWAR) in San Diego, officials from a number of federal, state, tribal and local agencies hope to better understand how water flows into and Dyes Inlet.
This is a fairly costly survey, said Frank Meriwether, an environmental engineer with the state Department of Healths Shellfish Program. The Navy, the city, the county, the Suquamish Tribe and we couldnt do this without this level of cooperation.
Navy officials hope to learn how to predict the tide and wind-driven currents and mixing patterns of Sinclair and Dyes inlets. That would allow them to identify how pollutants are transported through the two waterways.
Theres a lot more questions about waterflow in Dyes Inlet, said Jerry Sherrell of the environmental division at Puget Sound Naval Shipyard. Out on Sinclair Inlet its a pretty standard model.
Money for the study is coming from the shipyards Environmental Investment program, which is designed to protect and improve the health of Sinclair Inlet.
The dye technique first was tested in October 2000. The test found that tide waters tend to get caught on a jutting Tracyton shoreline, then swirl around until the tide recedes.
Sherrell said he hoped data from this weeks survey, once processed by SPAWAR, could be shared by myriad agencies in a couple months.
Tuesday, two boats tracked the dye using monitoring devices capable of detecting the susbstance even when it was invisible to the naked eye. A third boat collected water quality samples to measure levels of nutrients, pesticides, metals and other pollutants at several locations.
A drogue equipped with a global positioning system was placed at the front edge of the dye plume.
Stormwater and sewage discharge cause some of the pollution, which has led to a prohibition on commercial and sometimes recreational shellfish harvests since 1969.
Bremerton made considerable efforts to reduce its stormwater pollutants and they continue to do so, Meriwether said. Its a good time to put this model together.
Chance Berthiaume of Bremerton Public Works said ultraviolet lights at the new treatment facility near Lebo Boulevard in East Bremerton remove nearly all pollutants before the water is discharged into the Point Washington Narrows.
Thats good news for the Suquamish Tribe, which wants to resume commercial shellfish harvests in Dyes Inlet.
Dyes Inlet has always been an important place for shellfish harvesting, said Rob Purser, Suquamish fisheries director. Ever since the inlet became too polluted to harvest, it has put a burden on our need for resources.