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HomeMy WebLinkAboutC_OnholdLetter_220726_v2 August 5, 2022 KPFF Consulting Engineers Attn: Timothy Prusa 1601 Fifth Avenue, Suite 1600 Seattle, WA 98101 SUBJECT: "On Hold" Notice Maple Highlands Preliminary Plat / LUA22-000122, ECF, PP Dear Mr. Prusa, The Planning Division of the City of Renton accepted the above master application for review on April 20, 2022. During our review, staff has determined that additional information is necessary in order to proceed further. The following information will need to be submitted so that we may continue the review of the above subject application:  Significant trees shall be retained in the order of priority presented in RMC 4-4-130H.1.b. The first two (2) items for Priority One are (i) landmark trees, and (ii) significant trees that form a continuous canopy. Trees 97 through 101 meets both items and are of the highest priority to preserve. The first two (2) items for Priority Two are (i) healthy tree groupings whose associated undergrowth can be preserved, and (ii) Other significant native evergreen or deciduous trees. Trees 1 through 30 meet these priorities. Tree 105 meets the third item of Priority Two, (iii) other significant non-native trees. Preservation. Preservation of Trees 1 through 30, 97 through 101, and 105 is a priority for Planning as they meet multiple priority items and can be retained through development. Trees 1 through 30 can be retained in a tract and still maintain R-4 zoning minimum lot requirements. Planning will not support removal of them. Retention of an arborist to monitor construction with lower impact construction around Trees 97 through 101 and 105 will be a recommended condition of approval.  Please see attachments and the following comments from Development Engineering: o Civil Plans  Storm Pond Access Road Grading: the slope for the road exceeds the maximum 15%. Ensure that turning radius is minimum 40 feet. Revise road.  Storm Pond Walls: Based on the elevations, it appears that the storm pond walls will protrude above the ground surface, roughly 3 feet. Show exposed height elevations for clarity.  Storm Pond Berm: Berm top minimum width must be 6 feet.  Suggestion: may want to consider a detention vault due to grading, setbacks, and retaining wall height restrictions. o TIR  BMP: Basic Dispersion is feasible, per 25-foot vegetated flow path. This BMP shall be considered.  New street runoff on 154th Avenue SE must be captured and treated via the pond. Revise this.  Flow Control Table: provide detention pond Information in a table, in the TIR (Depth of Pond, Detention Volume (Live), Riser Height, Riser Diameter, Orifice 1 &2 diameter & elevation). o Mitigation  See attached flood photos from neighboring properties. Mitigation measure, can be addressed at the civil permit review (after LUA): replace two (2) existing driveway culverts with 12” Ductile Iron Pipe, and design new ditch to convey flows from 18” outfall to 3rd driveway (see screenshot below): At this time, your project has been placed “on hold” pending receipt of the requested information. The maximum time for resubmittal shall be within 90 days of this notice. Please contact me at (425) 430-7286 if you have any questions. Sincerely, Andrew Van Gordon Associate Planner cc: Theresa Bagnell, Paula Chambers / Owners Aron Golden / Applicant Marv Bettes, Paula Chambers, Scott Christensen, Roger Overa / Party(ies) of Record