Why Has Redmond Updated its Stream Classification?

The Washington State Growth Management Act (GMA) requires that all County and Municipal Government Critical Areas Ordinances (CAO) be updated based on “Best Available Science,” preferably before January 2005. This includes updating local stream classification systems and their associated protective riparian stream buffer requirements.

The most widely used stream classification system in Washington is the “water typing” system developed and implemented by the Washington Department of Natural Resources (WDNR). This system was recently updated (January 2005) and Redmond has adopted the concepts behind these classification changes.

The fundamental change in WDNR’s water typing system is the development of more accurate maps of fish habitat. These maps are based upon a multiparameter, geographic information system logistic regression model. The distribution of fish habitat is predicted using geomorphic parameters such as basin size, gradient, and elevation, and can be verified by on the ground surveys. In producing these improved maps, WDNR has acknowledged the need for a better understanding of fish distribution statewide. The City of Redmond similarly recognizes that responsible protection and restoration of our critical areas depend directly on knowing exactly where fish and supporting habitat occur.

It is important to note that the new water typing system retains key concepts from its predecessor:

• In the absence of fish, a water body can still be designated “fish-bearing” if the associated habitat has “the potential to support fish.” This fish-bearing potential is determined by specific physical attributes of the stream habitat, including channel width and gradient.
• Downstream man-made barriers to fish passage are not sufficient reason to classify upstream habitat as incapable of supporting fish, since upstream fish access may be regained in the future upon removal of such barriers.

Redmond has adopted both of these existing concepts.

Prior to 2004, Redmond’s knowledge of the species composition and distribution of fish populations within City streams was very basic. Observations were generally limited to third-party records (Salmon Watchers volunteer program; King County staff; Dept. of Fish and Wildlife staff) of adult salmonids moving through the Sammamish River and Bear and Evans Creeks to spawn.

To remedy this situation, in Spring 2004, and again in Spring 2005, the City of Redmond contracted with Washington Trout—a respected, local, science-based non-profit organization—to perform systematic sampling of the fish in most of our smaller City streams (all tributaries to Lake Sammamish, the Sammamish River, or Bear and Evans Creeks), and to assess the adequacy of our City stream habitats to support fish. Most of the fish they documented—and there were plenty of them—were juvenile trout and salmon that we did not know were using our streams.

King County has also chosen to adopt the updated WDNR water typing/stream classification system, thus Redmond’s use of a similar classification allows comparisons with other streams across the region to be made more easily.

How Has Redmond Natural Resources Chosen to Use Washington Trout’s Data?

Natural Resources chose Washington Trout to survey City stream habitats and fish populations based on its integrity, objectivity, and extensive prior experience working with both municipal and regulatory jurisdictions to accurately classify streams using the WDNR water typing protocol. Their acknowledged advocacy on behalf of protecting streams and fish also provides the City with stronger safeguards to protect our natural heritage for future generations.

After careful review of all of the materials provided by Washington Trout to the City, and following extensive joint discussions, Natural Resources chose to adopt their complete study results.

There are several special circumstances that the City of Redmond must address, however, that require some modification and additional interpretation of Washington Trout’s study results. These special circumstances are outlined below:

(1) The Growth Management Act requires that affected jurisdictions “…provide special protections for anadromous fish” (e.g., salmonids). The best available science indicates that salmonids are among the most widely distributed of all local fish and are likely to move further upstream than any other species.

The WDNR water typing system provides equal protection to all species of fish and their habitats (under WDNR Type F, fish-bearing or with the potential to be fish-bearing) but in order to meet the spirit of the GMA, Redmond has chosen to emphasize special protection for salmonids and their habitats, defining these as Class II Streams, which have wider protective buffers.

(2) Redmond has a special class of small, perennial and seasonal valley wall streams. These streams typically rise along the crest of the Sammamish River valley wall, gather flow from springs and seeps as they flow down the valley walls, and then infiltrate into the ground when they reach the valley floor. Most never reach larger streams or the Sammamish River.

Several of these streams contain populations of native sticklebacks and thus warrant protection as fish-bearing streams (WDNR Type F), but since they lack connections to river tributaries they are unlikely to contain salmonids. Redmond has chosen to define these as Class III Streams that support non-salmonid fish use, or have the potential to support non-salmonid fish. This Class has narrower protective buffers than our salmon-bearing streams.

Also included under Redmond’s Class III are streams without fish and without any potential to support fish that are connected downstream to either Class I or Class II salmonid-bearing streams. While these streams don’t contain fish themselves, they can be critical “headwater streams,” providing cold, clean water to the salmon-bearing streams into which they flow, further downstream.

(3) Redmond’s Class IV Streams combine both WDNR category Np and Ns streams—perennial and seasonal streams that neither support, nor have any potential to support, any fish.

(4) In addition to natural or modified natural streams, Redmond has some “Intentionally Created Streams,” man-made ditches and swales, generally created for irrigation or drainage purposes. If fish are found within such streams, then they are subject to the same protective buffer requirements of natural fish-bearing streams.

This category specifically excludes man-made streams that are created as part of stream habitat restoration efforts or in response to mitigation requirements—such intentionally created streams are regulated the same as other Redmond streams.