§ 24.25.330. Stream relocation.

The approval authority, in consultation with state and federal agencies with jurisdiction, may only allow streams to be relocated subject to state permit requirements, provided the proposal complies with the following:

A.

Plans. The applicant shall submit plans identifying the extent to which the stream would be altered. The plans shall depict the existing stream channel, the location of the proposed stream channel, site topography with contours at two-foot intervals or less, proposed uses or restoration of the original stream channel including any grading and filling, proposed stream bed design and materials, the channel migration zone, stream bank stabilization, riparian area enhancement/restoration, and methods to preserve and relocate existing fish and aquatic life affected by the project.

B.

Equal or Better Habitat Function. The replacement stream channel provides an equal or better habitat for all fish species, and affected important marine species, maintains or improves water quality, and does not have a net adverse impact on other critical areas.

C.

Replicate or Improve Stream Characteristics. The original ecological value of the stream and riparian habitat area shall be recreated or enhanced, to the extent feasible. The natural channel dimensions shall be replicated or improved including substantially identical depth, width, length, gradient, channel complexity and horizontal alignment (meander lengths) as the original location or the upstream and downstream channel. The stream bottom shall be restored with materials identical or similar to the original streambed. Removal of vegetation and large woody debris (logs) shall be minimized. However, the approval authority may allow deviation from the original conditions if it is determined that an alternative configuration or materials would improve habitat quality (e.g., by adding structure, cover, pools, spawning gravels, etc).

D.

Flooding. The flood carrying capacity of the relocated stream and floodplain shall not be diminished, as demonstrated by a professional engineer licensed in the State of Washington. (Also see Chapter 24.20 TCC, Frequently Flooded Areas.)

E.

Channel Migration Zone. The applicant shall identify the channel migration zone for the watercourse at the project site and for the reach upstream and downstream of the site (for a distance of at least five hundred feet). The design and construction of the project shall not preclude channel movement, except as necessary to protect public safety or existing structures, consistent with TCC 24.25.300.

F.

Impacts on Marine Habitat. Stream relocation shall minimize impacts to important marine habitat protected by this chapter. Any impacts to such areas shall be mitigated. Relocated streams entering Puget Sound shall not be contained in pipes within the marine riparian habitat area, with the exception of road crossings permitted consistent with this chapter.

G.

Riparian Width and Condition. Any stream that is relocated shall have a riparian habitat area width as specified in Table 24.25-1 or as modified pursuant to TCC 24.25.015-24.25.040. The stream bank configuration shall be restored to the original or improved conditions, consistent with the latest edition of WDFW's Integrated Streambank Protection Guidelines. The riparian habitat area shall be replanted with native vegetation that replicates the natural, undisturbed riparian condition in species, size and densities.

H.

Blockages. Stream alteration projects in Type S and F streams shall not result in blockage of side channels that would impede fish or adversely impact other priority wildlife species. Known fish barriers in side channels involved in the project site shall be removed as part of the approved stream alteration project.

I.

Monitoring and Surety. The applicant shall submit a monitoring plan for county approval to ensure that the project functions as approved. The applicant also shall submit a surety to the county, consistent with TCC 24.70, sufficient to correct any project failures or to replace any vegetation that does not survive.

(Ord. No. 14773, § 3(Att. B), 7-24-2012)