Vashon Island Water Type And Stream Mouth Assessment
June 2000, 2001
In 2000 and 2001, Washington Trout performed a comprehensive water-typing survey on Washington's Vashon Island, located west of Seattle in central Puget Sound, to ensure that the Island's trout and salmon streams receive the maximum legal protections available.
With funding from the Vashon/Maury Island Audubon Society, the Trout and Salmon Foundation, the General Service Foundation, and King County Department of Natural Resources, Washington Trout responded to a request from Vashon Island community organizations to survey Vashon Island's streams to identify which are being used by salmon and trout. The community groups were concerned about the effects that development and other land use practices are having on the Island's native salmon and trout streams. In the face of growing development, the Island's native fish populations need legal and regulatory protection, and accurate stream typing is vital to getting them that protection.
Washington Trout crews surveyed 75 streams on Vashon Island, verifying fish presence by visual observation or by electro-fishing. The project upgraded the classification of approximately 33 miles of the approximately 88 miles of stream identified and/or surveyed. All water-typing data have been recorded, analyzed, and submitted to the Washington Department of Natural Resources (WDNR) to amend water-type maps. The new classifications will be translated into King County Sensitive Area Ordinance designations. During the course of the surveys, crews made supplementary habitat observations and recorded provisional data on the following parameters: sediment sources, barriers to fish migration, last-fish observations, in-stream features, water supplies, and photo-points.
Washington Trout's Habitat Lost & Found program is based on two fundamental salmon-recovery strategies, correcting the misidentification of salmon habitats to qualify them for existing regulatory protection, and assessing and repairing man-made barriers that block wild salmon and trout from critical habitats. Habitat Lost & Found has protected and re-opened hundreds of miles of salmon and trout habitat statewide, and affected positive change in state regulations and management practices.
Washington's streams are regulated by the WDNR, classified under five “types.” Type-one, -two, and -three streams are fish-bearing. Type-four and -five streams are non fish-bearing. Accurate stream typing is essential to protecting fish and their habitats. For example, riparian buffer zones required on type-two streams are greater than those required on type-four streams.
WDNR's original stream typing underestimated the actual miles of fish-bearing streams by almost 50% statewide. Streams that deserved protection did not get it, and hundreds of miles of wild salmon and trout habitat were lost. In 1997, responding to data from Washington Trout and Quinault tribal biologists, WDNR revised its physical default criteria for identifying fish-bearing streams, and upgraded protections for waters contemporarily identified as non fish-bearing. However, the ruling is applicable only to lands regulated for forest practices. Most local jurisdictions rely on WDNR's old, often inaccurate water-typing maps. Many streams facing threats from development and associated land-use practices are still not being adequately protected.
Under its Habitat Lost and Found program, Washington Trout has carried out water-typing surveys on over 4500 streams throughout Washington, upgrading the status of thousands of fish-bearing streams.
Vashon Island is located near Seattle in central Puget Sound. It is relatively small (approx. 36 sq. miles), drained by typically small, low gradient streams, many shorter than one mile, most previously classified as non fish-bearing. Only a handful of the Island's relatively larger streams were classified as type-three or above. Many potentially fish-bearing streams on the Island were unclassified or not identified on maps at all, qualifying for no legal or regulatory protection whatsoever.
The streams of Vashon Island provide habitat for coho (Oncorhynchus kisutch) and other salmon species, and sea-run cutthroat trout (O. clarki). Puget Sound coho are a candidate for listing under the Endangered Species Act. Sea-run cutthroat populations in Puget Sound have severely declined, due mostly to habitat loss and degradation.
During June, 2000 Washington Trout crews surveyed 73 streams on Vashon Island according to WDNR protocols (WAC 222-16-030), physically walking each stream, verifying fish presence by visual observation or by electro-fishing. The project was completed in May and June 2001 when the survey of Triplebrook Cr. and Judd Creek, the largest and final stream system on Vashon, was finished. During the course of the surveys, crews recorded supplementary habitat observations, including data on sediment sources, barriers to fish migration, species encountered, in-stream features, water supplies, and photo-points. In August 2001, Washington Trout circumnavigated Vashon Island to document the condition of the stream mouths around the island. The supplementary data included in the map set accompanying this document are presented as provisional, and do not represent comprehensive data for these parameters.
The project upgraded approximately 33 of the approximately 88 miles of stream identified and/or surveyed. Two streams that had been classified as non fish-bearing were upgraded to type-two (showing significant fish use). WT found direct evidence of coho salmon in at least two streams, Shinglemill Creek and Baldwin Creek, and substantial use by sea-run cutthroat trout throughout the island's streams. Washington Department of Fish and Wildlife records indicate that coho and chum salmon (O. keta) have historically used several other island streams.
Shinglemill Creek is the second largest stream on the Island, approximately 10.8 miles long. Crews found substantial and significant anadromous fish use by sea run cutthroat and coho salmon, upgrading 2.17 miles of Shinglemill Creek from non fish-bearing to fish-bearing. Another one mile of Shinglemill was upgraded from type-three fish-bearing water to type-two fish-bearing water. Crews also collected data to upgrade two sections of Fisher Creek, another of the Island's larger systems, to type-two. Lower Fisher was upgraded from a type-three to a type-two stream based on significant anadromous fish use by sea-run cutthroat. Sections of upper Fisher Creek were upgraded to type-three, and another un-typed section will be upgraded to a type-two water supply. Ellis Creek, identified as a type-four stream on the WDNR base map, was upgraded to a type-two water supply. WT crews found fish all the way to a fish-blocking diversion dam on Ellis Creek, suggesting that without the barrier, the creek could be providing even more fish habitat.
Baldwin Creek drains directly into Puget Sound at Fern Cove, sharing that estuary with Shinglemill Creek, one of the Island's most important anadromous streams. Baldwin Creek is tiny, less than one mile long and barely two feet wide. It had been classified as a type-five, non fish-bearing stream. WT crews found direct evidence of fish use by both sea run cutthroat and coho salmon, and Baldwin Creek will be upgraded to type-three.
All water-typing data have been recorded, analyzed, and submitted to WDNR to amend water-type maps according to state water-type criteria. The new classifications will be translated into King County Sensitive Area Ordinance (SAO) designations. Type-three and type-two under state water-type criteria will be categorized as Class 2S (with salmonids) under SAO designations, and qualify for protections that include 100 foot stream buffers. Streams upgraded to type-four under state water-type criteria will be categorized as Class 2P (perennial), and qualify for protections that include 50 foot stream buffers. Streams upgraded to type-five under state water-type criteria will be categorized as Class 3, and qualify for protections that include 25 foot stream buffers.
In August 2001, Washington Trout circumnavigated Vashon Island to document the condition of the stream mouths around the island. Crews evaluated each identified stream mouth for fish passage, categorizing each as unobstructed, obstructed, or undetermined. Stream mouths that were either fully or partially obstructed, and likely impeded or prevented access to the stream by anadromous fish were identified as obstructed. The nature of each obstructed stream mouth was further characterized as anthropogenic (impassable culvert at the mouth, for example), natural (channel gradients exceeds 20% at the mouth, for example), or both anthropogenic and natural. Each stream mouth was photographed; a GPS point was collected to document each stream mouth’s location; and notes characterizing each stream mouth and adjacent features were recorded. The survey identified 136 stream mouths around the island. Of these, 102 (75%) were characterized as obstructed, 32 (24%) as unobstructed, and 2 (1%) as undetermined. Of the obstructed stream mouths, 40 (39%) had anthropogenic barriers, 35 (34%) had natural barriers, and 27 (27%) had both natural and anthropogenic barriers.
Many of the type-four and -five streams that drain directly to the shoreline around the Island may have functioned as possible rearing and over-wintering habitat for juvenile fish, but are now completely blocked from estuaries and near-shore habitats by bulkheads and culverts. During the course of the surveys, crews identified scores of other fish barriers, including road culverts and derelict water supply systems. Many currently used water systems, including the County's, are barriers as well.
Water use may be another significant limiting factor for the Island's native fish. Water supply systems block fish migration and alter the hydrology of the streams. Current maps do not even show the source points for many streams (springs), many of which are Type-two water supplies. The Island's streams are almost entirely fed by ground water, and the decreased average flow in many streams may be evidence that Vashon Island's aquifers are being depleted. Water District 19 diverts a substantial amount of water from Beall Creek, a type-two water supply. The Water District has significantly de-watered the stream during different times of the year. WT crews found fish in Beall Creek right up to the water-diversion barrier.
As Vashon Island faces the same rapid growth pressures being suffered throughout the Greater Puget Sound area, its native fish habitats need to be sufficiently protected to avoid degrading the Island's environment, its quality of life, and its wild fish populations. Accurately classifying the Island's wild-fish habitats is vital to preserving and restoring their productivity.
The project has helped develop a factual baseline for the whole community to use in making land-use decisions. Vashon Island planning entities and relevant resource management agencies can use the results of the Vashon Island Water Type Survey to evaluate the health of the Island's streams, identify problems, determine the potential for improving stream productivity, and make efficient and responsible planning decisions.
The project has upgraded 38% of the stream mileage included in the water typing survey. Stream reaches that had been misidentified or unidentified will now receive the regulatory protection they qualify for. These findings reinforce a pattern identified in Washington Trout's larger Habitat Lost & Found program, underscoring the need for accurate, comprehensive, and consistent water typing across Washington's landscape.
Vashon Island residents and community groups are concerned about the pace and direction of land use on the Island. They know that wild native fish use the Island's streams, and they understand the contribution those fish make to the quality of life on the Island.
Volunteers from the Vashon Island Audubon Society put in hundreds of hours raising money, publicizing the stream surveys, contacting landowners to get permission to survey streams on private property, and guiding the WT team in the field. Landowners voluntarily welcomed the WT team, in many cases accompanying them, showing them stream features, asking for advice and information. The cooperation of stream owners made it possible to look at key parts of nearly every stream on the island, and in most cases the entire length of year-round streams.
Washington Trout gratefully acknowledges the support and help of Ken Fulton, a Vashon Island resident, who donated his boat and navigational skill, to carry out the week-long stream mouth survey.
The project was also made possible by funding from the Trout and Salmon Foundation, the General Service Foundation, King County, and the Vashon Island Audubon Society.