Ord-2021-016 - Laserfiche WebLink

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A sloLe is delineated by establishinq its toe and top and measured by averaginq the inclination over at least ten (10) feet of vertical relief: ix. Potentially unstable slopes resulting from river erosion or undercuttinq: x. Areas that show past slouqhing or calving of sediment or rocks resultinq in a steep slope that is poorlv veqetated: xi. Deep-seated landslide areas characterized bv one or more of the following features: scallooed ridqe crests at the top of the slooe. crescent shaped depressions. head scarps. side scarps. ponds or saq areas on mid slopes. benches and scarps on mid slope areas. hummockv oround, linear fractures in the oround. These features mav be evident in aerial imaqes, topooraphic maps. L|DAR imaqerv or on the qround: xii. Areas below unstable slopes or that have been identified as landslide hazard areas that could be impacted by landslide run out: and xiii. Areas above or adiacent to unstable slopes that could be impacted if the landslide area expands. b. Potential Erosion Hazard Areas. Erosion hazard areas shall include areas containinq soils that mav experience sionificant erosion. including:i. Soil areas identified by the Natural Resources Conservation Service as havinq "severe" or "very severe" erosion hazard.ii. Slopes fortv percent (40%) or steeper with a vertical relief of ten (10) or more feet. except areas composed of consolidated rock. iii. Concave slope forms equalto or greater than fifteen percent (15%) with a vertical relief of ten (10) or more feet. except areas composed of consolidated rock. iv. Channel mioration zones. which are defined as the areas alonq a river or stream within which the channel(s) can be reasonably predicted to miqrate over time as a result of natural and normally occurrinq hydroloqical and related processes when considered with the characteristics of the river and its surroundinqs.c. Alluvial Fan Hazard Areas. Alluvialfan hazard areas shall include those areas on alluvial fans where debris flows. debris floods. or clear water floods have the potential to significantlv damaoe or harm the health or welfare of the community. Thev include the area qenerallv correspondinq to the path of potential floodinq. channel chanqes. sediment and debris deposition. or debris flow paths as determined bv analvsis of watershed hvdroloqv and slope conditions, topographv. valley bottom and channel conditions. ootential for channel chanqes. and surface and subsurface qeoloqv. i. lf the approval authority determines that a proposed use alonq a Tvpe S or F stream is within a historic channel miqration zone. based on field conditions. historic information. LIDAR imaqery or aerial photoqraphy. and the one- hundred-year channel miqration hazard area has not been mapped. the approval authority shall require the applicant to determine if a one-hundred- vear channel miqration hazard area is present on the site and. if so, delineate its location and extent. ii. The determination as to whether the one-hundred-vear channel miqration hazard area affects the subject propefty shall be based on the findings of a qualified professional proficient in fluvial qeomorpholoqv usinq a reliable methodoloqv to determine channel miqration accepted bv the department (e.9.. as described in the Washinoton Department of Natural Resources' Forest Practices Board Manual. Standard Methods for identifuinq Channel Miqration Zones and Bankfull Channel Features. dated 8/2001, as amended: or in "A Framework for Delineatinq Channel Mioration Zones." Washinqton Department of Ecolooy. 2003, as amended). Maps delineatino the one- 50