FP24-007 Staff Decision - Laserfiche WebLink

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distanced from the river to the greatest extent possible. The restroom structure location is related to the campground and therefore also distanced to the greatest extent possible. The criterion is met. Q. The development, change or intensification of use shall provide the maximum possible landscaped area, open space or vegetation between the activity and the river. The applicant attests that although 14 total trees will be removed for the expansion of the campground, construction of the restroom structure, and construction of the cabins, the green buffer between the campground and the river will be left intact. The criterion is met. R. Private docks, wharfs, and covered storage shall be limited to one per property ownership, shall not extend more than 10 feet above water level, and shall be limited to 300 square feet of gross area. Walkways to the dock, wharf or covered storage shall be not more than five feet wide. The criterion does not apply. The proposal appears to be consistent with all considerations and criteria for development within the greenway overlay. 9. The purpose of the Floodplain Overlay Zone is to promote public health, safety and general welfare to minimize public and private losses due to flood conditions. In order to ensure that the development is reasonably safe from flooding, the County requires the development comply with the criteria and standards listed in Section 17.178.050 and 17.178.060 of Marion County Code (MCC). 10. Champoeg State Park extends across four Flood Insurance Rate Maps: #41047C0025G, #41047C0050G, #41047C0125G, & #41047C0130G. This area is in an “AE” floodplain zone. The applicant will be responsible for developing a Base Flood Elevation for each of the development sites. The applicant received an approved LOMA (Case no: 24-10-0376A) from FEMA for the area where the cabins are planned to be located. Therefore, the following floodplain criteria apply to the restroom facility, propane tanks and the grading required for the campsites and roadways. 11. Marion County Code 17.178.050 C, D & E pertain to this project: C. Prior to obtaining a building permit the owner shall be required to sign and record in the deed records for the county a declaratory statement binding the landowner, and the landowner’s successors in interest, acknowledging that the property and the approved development are located in a floodplain. This declaratory statement shall be a condition of approval. D. Prior to obtaining a building permit, commencing development or placing fill in the floodplain the applicant shall submit a certification from a registered civil engineer demonstrating that a development or fill will not result in an increase in floodplain area on other properties and will not result in an increase in erosive velocity of the stream that may cause channel scouring or reduce slope stability downstream of the development or fill. Applicants provided a memo from Scott Schumaker of PBS Engineering and Environmental summarizing the results of the modeling of Willamette River adjacent to the subject property. PBS used HEC-RAS data to analyze pre- and post-project water surface elevations and channel velocities. The results show no increase in surface elevations, therefore no increase in floodplain area on other properties. The results do show a 0.04-fps increase in velocity at a single cross section, but PBS is confident this minimal increase will not result in a measurable increase in channel erosion. The negligible increase in velocity ensures that the proposed project will not cause channel scouring or reduce slope stability downstream of the development. Engineer certification verifying the provided memo will be required as a condition of approval.