18.01.030 Designation and mapping of critical areas.
A. All areas within the city meeting the definition of one or more critical areas defined above are hereby designated critical areas and are subject to the provisions of this chapter except for critical areas within the city of Cle Elum shorelines. The city of Cle Elum shoreline master program supersedes this chapter for only those critical areas within shoreline designations.
B. The city of Cle Elum shall regulate all uses, activities and developments within, adjacent to, or likely to affect, one or more critical areas, consistent with the best available science and the provisions herein.
C. Wetlands Designation. Wetlands are those areas, designated in accordance with the procedures outlined in WAC 173-22-035. All areas within the city meeting the wetland designation criteria as outlined in WAC 173-22-035 are hereby designated critical areas and are subject to the provisions of this chapter. Wetlands shall be rated according to the Ecology wetland rating system found in the Washington State Wetland Rating System documents (Eastern Washington, Ecology Publication No. 04-06-030) or as revised by Ecology. Wetland delineations are valid for five years; after such date the city shall determine whether a revision or additional assessment is necessary.
1. The approximate location and extent of known wetlands are shown on the adopted critical area map, or the latest revision of this map, as derived from the National Wetlands Inventory. The city’s critical area mapping, National Wetland Inventory Map, Soil Surveys, and any Washington Department of Natural Resource wetland mapping are to be used as a guide for the city, project applicants, and/or property owners to identify potential wetland areas, but do not provide a conclusive or definitive indication of wetland presence or extent. Other wetlands may exist that do not appear on the maps and some wetlands that appear on these maps may not meet all of the wetland designation criteria.
2. The exact location of a wetland’s boundary shall be determined through the performance of a field investigation by a qualified professional.
D. Critical aquifer recharge areas (CARAs) are those areas with a critical recharging effect on aquifers used for potable water as defined by WAC 365-190-030(2). CARAs have prevailing geologic conditions associated with infiltration rates that create a high potential for contamination of groundwater resources or contribute significantly to the replenishment of groundwater. Aquifer recharge areas shall be rated as having high, moderate, or low susceptibility based on soil permeability, geologic matrix, infiltration, and depth to water as determined by the criteria established by Ecology.
The city lies over alluvial soil deposits. There are unconsolidated materials composed of silt, sand and gravel, which in places are several hundred feet in depth. This deposit material is important as a water conveying unit and supplies the groundwater of stream flow (recharge). In general, areas of permeable soils in combination with geological transfer structure may be aquifer recharge areas. Based on the information and maps contained in hydrology of the Upper Yakima River Basin and landscape planning, environmental applications, the city is an aquifer recharge area. This is a preliminary determination until further studies of geology and hydrology are conducted on an overall or individual property specific basis to either include or exclude them as an aquifer recharge area.
E. Frequently flooded areas are those areas subject to at least a one percent or greater chance of flooding in any given year, or within areas subject to flooding due to high groundwater. These areas include:
1. Waterways (streams, rivers, lakes, coastal areas, wetlands, and areas where high groundwater forms ponds on the ground surface). This includes Crystal Creek and ephemeral drainages identified by DNR and the Washington Department of Fish and Wildlife (WDFW).
2. Floodways and floodplains identified in the most recent FEMA flood insurance rate map, and as subsequently revised and amended.
F. Geologically hazardous areas are areas susceptible to erosion, sliding, earthquake, or other geological events, that are not suited to the siting of commercial, residential, or industrial development consistent with public health or safety concerns. Geological hazardous areas as designated by WAC 365-190-080 include the following areas:
1. Erosion Hazard Areas. Erosion hazard areas are at least those areas identified by the U.S. Department of Agriculture Natural Resources Conservation Service as having a “moderate to severe,” “severe,” or “very severe” rill and inter-rill erosion hazard. Erosion hazard areas are also those areas impacted by shore land and/or stream bank erosion and those areas within a river’s channel migration zone.
2. Landslide Hazard Areas. Landslide hazard areas are areas potentially subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include areas susceptible because of any combination of bedrock, soil, slope (gradient), slope aspect, structure, hydrology, or other factors, and include, at a minimum, the following (per WAC 365-190-120(6)):
a. Areas of historic failures, such as:
i. Those areas delineated by the U.S. Department of Agriculture Natural Resources Conservation Service as having a significant limitation for building site development;
ii. Those coastal areas mapped as class u (unstable), uos (unstable old slides), and urs (unstable recent slides) in the Ecology coastal atlas; or
iii. Areas designated as quaternary slumps, earthflows, mudflows, lahars, or landslides on maps published by the United States Geological Survey or Washington Department of Natural Resources.
b. Areas with all three of the following characteristics:
i. Slopes steeper than fifteen percent;
ii. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock; and
iii. Springs or groundwater seepage.
c. Areas that have shown movement during the holocene epoch (from ten thousand years ago to the present) or which are underlain or covered by mass wastage debris of this epoch;
d. Slopes that are parallel or subparallel to planes of weakness (such as bedding planes, joint systems, and fault planes) in subsurface materials;
e. Slopes having gradients steeper than eighty percent subject to rockfall during seismic shaking;
f. Areas potentially unstable as a result of rapid stream incision, stream bank erosion, and undercutting by wave action, including stream channel migration zones;
g. Areas that show evidence of, or are at risk from, snow avalanches;
h. Areas located in a canyon or on an active alluvial fan, presently or potentially subject to inundation by debris flows or catastrophic flooding; and
i. Any area with a slope of forty percent or steeper and with a vertical relief of ten or more feet except areas composed of bedrock. A slope is delineated by establishing its toe and top and measured by averaging the inclination over at least ten feet of vertical relief.
j. Any area with a slope of forty percent or steeper and with a vertical relief of ten or more feet except areas composed of bedrock. A slope is delineated by establishing its toe and top and measured by averaging the inclination over at least ten feet of vertical relief.
k. Known landslide areas documented by the Washington State Department of Natural Resources (DNR) (2020) and those areas with slopes greater than thirty-five percent.
l. Known mass wasting areas identified in the 2005 Landslide Hazard Zonation Project – Mass Wasting Assessment prepared by Powell, L.
3. Seismic Hazard Areas. Seismic hazard areas are areas subject to severe risk of damage as a result of earthquake-induced ground shaking, slope failure, settlement or subsidence, soil liquefaction, lateral spreading, or surface faulting. Settlement and soil liquefaction conditions occur in areas underlain by cohesionless soils of low density, typically in association with a shallow groundwater table. One indicator of potential for future earthquake damage is a record of earthquake damage in the past. Ground shaking is the primary cause of earthquake damage in Washington, and ground settlement may occur with shaking. As specified in WAC 365-190-120(7), the strength of ground shaking is primarily affected by:
a. The magnitude of an earthquake;
b. The distance from the source of an earthquake;
c. The type or thickness of geologic materials at the surface; and
d. The type of subsurface geologic structure.
The Washington Department of Natural Resources Seismic Scenario Catalog, liquefaction susceptibility, and U.S. Department of Agriculture Natural Resource Conservation Service soil surveys should be consulted. These maps are a reference and do not provide a conclusive or final critical area designation.
4. Mine Hazard Areas. Mine hazard areas are those areas underlain by, adjacent to, or affected by mine workings such as adits, gangways, tunnels, drifts, or air shafts. Factors which should be considered include: proximity to development, depth from ground surface to the mine working, and geologic material.
5. Volcanic Hazard Areas. Volcanic hazard areas are areas subject to pyroclastic flows, lava flows, debris avalanche, and inundation by debris flows, lahars, mudflows, or related flooding resulting from volcanic activity.
6. Steep Slopes. Known landslide areas documented by the Washington State Department of Natural Resources (DNR) (2020) and are those areas with steep slopes greater than thirty-five percent.
7. Other Hazard Areas. Geologically hazardous areas shall also include areas determined by the director to be susceptible to other geological events including mass wasting, debris flows, rock falls, and differential settlement.
G. Fish and wildlife habitat conservation areas include the following:
1. Federally Designated Endangered, Threatened and Sensitive Species. Areas with which federally designated endangered, threatened and sensitive species have a primary association. Federally designated endangered and threatened species are those fish and wildlife species identified by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service that are in danger of extinction or threatened to become endangered. The U.S. Fish and Wildlife Service and the National Marine Fisheries Service should be consulted for current listing status.
2. State-Designated Endangered, Threatened and Sensitive Species. Areas with which state-designated endangered, threatened and sensitive species have a primary association. State-designated endangered, threatened, and sensitive species are those fish and wildlife species native to the state of Washington, identified by the Washington Department of Fish and Wildlife, that are in danger of extinction, threatened to become endangered, vulnerable, or declining and are likely to become endangered or threatened in a significant portion of their range within the state without cooperative management or removal of threats. State-designated endangered, threatened, and sensitive species are periodically recorded in WAC 232-12-014 (state endangered species) and WAC 232-12-011 (state threatened and sensitive species). The state Department of Fish and Wildlife maintains the most current listing and should be consulted for current listing status.
3. State Priority Habitats and Areas Associated With State Priority Species. Priority habitats and species (PHS) are considered to be priorities for conservation and management. PHS require protective measures for their perpetuation due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. PHS habitats are those habitat types or elements with unique or significant value to a diverse assemblage of species. A priority PHS habitat may consist of a unique vegetation type or dominant plant species, a described successional stage, or a specific structural element. Priority habitats and species are identified by the state Department of Fish and Wildlife.
4. Habitats and Species of Local Importance. Habitats and species of local importance are those identified by the city of Cle Elum, including but not limited to those habitats and species that, due to their population status or sensitivity to habitat manipulation, warrant protection. Habitats may include a seasonal range or habitat element with which a species has a primary association, and which, if altered, may reduce the likelihood that the species will maintain and reproduce over the long term.
5. Waters of the state.
6. Streams. All streams that meet the criteria for Type S, F or N (Np and Ns) waters as set forth in WAC 222-16-030 and provided in definitions in CEMC Section 18.01.020. Official water type reference maps maintained by the Department of Natural Resources should be consulted. These maps are a reference and do not provide a conclusive or final critical area designation.
7. Naturally occurring and manmade ponds under twenty acres in size.