35.20.200 Regulations.
(1) Flood control structures may be permitted through a conditional use permit as indicated in CCC 35.10.090, Table 2-2, when consistent with CCC 35.35.150 (Frequently Flooded Area Designation and Mapping) and 35.35.160 (Frequently Flooded Area Protection Standards), and other applicable provisions of this Program and when there is credible engineering and scientific evidence that:
(a) They are necessary to protect existing, lawfully established development; and
(b) They are consistent with CCC Title 32 and the County Comprehensive Plan; and
(c) Nonstructural flood hazard reduction measures are infeasible; and
(d) Impacts on Endangered Species Act-listed Puget Sound Chinook salmon, Puget Sound steelhead, Hood Canal summer-run chum salmon, and Southern Resident killer whales, and/or designated critical habitat for those species can be effectively mitigated consistent with NOAA’s 2008 Biological Opinion, or any successor thereto, on the Federal Flood Insurance Program; and
(e) Proposed measures are consistent with an adopted comprehensive flood hazard management plan if available.
(2) Flood hazard management and flood control structures shall comply with the applicable provisions of Chapters: 35.30 CCC, Shoreline Buffers and Vegetation Conservation; 35.35 CCC, Critical Areas within Shoreline Jurisdiction; 35.40 CCC, Mitigation and No Net Loss; and with the applicable articles: Article II of Chapter 35.25 CCC, Clearing, Grading and Filling; Article III of Chapter 35.25 CCC, Public Access; Article IV of Chapter 35.25 CCC, Water Quality and Water Management; and Article V of Chapter 35.25 CCC, Archaeological, Historical and Cultural Resources.
(3) When permitted, flood control structures shall be:
(a) Constructed and maintained in a manner that provides the highest degree of protection to shoreline ecological functions or processes and does not degrade the quality of affected waters or the habitat value associated with the aquatic and riparian area; and
(b) Placed landward of the ordinary high water mark except for weirs, current deflectors and similar structures whose primary purpose is to protect public bridges, roads, and other public infrastructure; and
(c) Placed landward of associated wetlands and channel migration zones except for structures whose primary purpose is to improve ecological functions; and
(d) Designed to allow for normal groundwater movement and surface runoff. Natural features such as snags, uprooted trees, or stumps should be left in place unless they are actually causing bank erosion or higher flood stages; and
(e) Designed to allow maintenance of bars and associated aquatic habitat through normal accretion. Flood control structures on streams shall not disrupt the normal meander progression nor lessen the stream’s natural storage capacity.
(4) When permitted, flood control structures shall be limited to the height required to protect adjacent lands from the predictable annual flood unless it can be demonstrated through hydraulic modeling that a greater height is needed and will not adversely impact shoreline ecological functions and processes.
(5) Solid waste such as motor vehicles, derelict vessels, appliances, or demolition debris shall not be used as part of any flood control structure.
(6) Flood control structures shall be professionally engineered and designed by a State licensed engineer prior to final approval. The design shall be consistent with the Department of Fish and Wildlife Aquatic Habitat Guidelines and other applicable guidance and regulatory requirements.
(7) No flood control structure shall be installed or constructed without the developer having obtained all applicable federal, State, and local permits and approvals, including but not limited to a Hydraulic Project Approval (HPA) from the Department of Fish and Wildlife.