Bainbridge Island Stream Type Assessment

Where are the streams on Bainbridge Island and what fish can be found in them? What makes these streams special? How can we help them regain their full capacity to thrive as healthy natural systems?

In an effort to help answer these questions, and to guide our protection and restoration efforts with landowners and others, the Land Trust has worked with partners to implement two stream-focused projects on Bainbridge Island.

A map of Bainbridge Island streams and our fish resources is available online here! You can navigate the map to view typed streams in Kitsap County, including Bainbridge Island. For more information on specific typed streams, simply click on the reach you’re interested in, and click on the photos for specific information on observed fish barriers and other stream features.

Stream Type Assessment
In 2014, the Wild Fish Conservancy (WFC), in partnership with the Land Trust, conducted a stream type assessment, or inventory, of the island’s watersheds as part of a regional effort to more accurately assess and identify fish bearing streams and their habitat. For the Land Trust, understanding where these valuable natural resources are is an important tool to help guide strategic restoration and protection efforts with landowners and other partners. The effort was funded by Washington State’s Salmon Recovery Funding Board, in recognition of the importance of protecting and restoring these fish resources.

Water typing or stream typing classification was originally developed for forest practices, and was then adopted by most local governments to identify and protect critical conservation areas. Most streams were not “typed” based on physical features or on-site inspection, but instead from a coarse, statewide remote mapping process. And the result? In previous maps, many streams were incorrectly classified (fish or non-fish), mismapped, or not included at all.

WFC and the Land Trust sent over 1,000 postcards to island landowners adjacent to or in close proximity to streams, asking permission for a survey team to enter their property to inventory the streams. 340 landowners agreed to allow the survey team onto their land to document stream features and find out what lived in those streams!

Stream Typing in Action
WFC biologist Aaron Jorgenson led stream-typing efforts on Bainbridge Island assisted by Molly Esteve, 2013-14 Land Trust AmeriCorps member and Deb Rudnick, Land Trust board member & Bainbridge Island Watershed Council Chair. From March to June, 2014 we successfully:

  • Collected over 720 GPS points
  • Took over 2,500 photos
  • Typed approximately 47 stream miles
  • Inventoried over 300 in-stream structures (such as culverts and diversion dams)
  • Caught and released over 100 fish, including Coho, Chum, Cutthroat Trout, Rainbow Trout, Stickleback and Sculpin

The chart below shows the original number of Island stream miles as mapped using the old technique (WA Dept. of Natural Resources Maps), and the results from the 2014 WFC survey.

Department of Natural
Resources (DNR)
Wild Fish Conservancy % Increase
 Stream Miles  26.6  47.3  79%
 Fish-Bearing Stream Miles  19.3  38.2  98%
 Non-Fish Stream Miles  7.3  9.1  25%

Why do we type streams?
In 1975, the Washington Department of Natural Resources (WDNR) developed the process of water typing – classifying streams into one of five types depending on their physical, biological, and human-use characteristics. Fish-bearing stream reaches are classified as Type 1, 2, or 3 according to fish abundance and physical characteristics of the stream channel; Type 4 and Type 5 streams are considered non fish-bearing. Water typing or stream typing classification was originally developed for forest practices, and then was adopted by most local governments to identify and protect critical conservation areas. Most streams were not “typed” based on physical features or on-site inspection, but instead from a coarse, statewide remote mapping process. And the result? Many streams were incorrectly classified (fish or non-fish bearing), mismapped, or not included at all.

Accurate water typing is essential to protecting fish and their habitats because type classification guides the proximity of allowable human activity for streams and other surface water. Riparian (areas alongside streams) buffer zones required on Type 2 streams, for example, are broader than those required on Type 4 streams.

In 1997, WDNR revised its criteria for classifying streams as fish-bearing and upgraded protections for waters identified as non-fish-bearing. Current Department of Natural Resources water type maps may under-represent the upstream extent of fish and fish habitat, and many streams are mapped incorrectly or not at all. So, streams may not receive adequate protection from adjacent land use practices.

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