4817 RUCKER AVE 2024-12-09 - Laserfiche WebLink

addition. The Geotech Report recommended foundation drains and blanket drains full height for the wall of the structure. There was no recommendation in the report on setbacks, consult with AESI on building setback requirement (if any) for infiltration on this specific project. The infiltration facility appears to be approximately 465 feet from a medium level landslide/erosion area and 550 feet from a high level erosion hazard area, this meets City setback requirements. The geotechnical engineer also conducted a slope stability analysis for the YMCA project, confirm with AESI if the analysis included infiltration from the park. The 9,971 sf rubberized surfacing is considered by Dept. of Ecology to be a pollution generating surface. Treatment will be required for flows from the rubber surface to the infiltration facility(provide treatment unit immediately upstream of infiltration facility). See Volume 5 Chapter 5 and 1-4 UIC Program for run-off treatment required for infiltration facilities. Infiltration facilities with a perforated pipe is considered a UIC well (per V1, Ch.4, S. 1-4.1) Register UIC well using Ecology's online registration process. See the following website for details: https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Underground-inlection- control-program/Register-UIC-wells-online Confirm if offsite areas from the south will be flowing into the site, based on the contours shown, it appears that it does. Will this flow end up in the infiltration facility? The catch basin downstream of the infiltration facility shall be provided with gas trap (prior to discharge to the sewer). It looks like there is an error in the two elevations listed for the infiltration facility. In the plan sheet,the inner elipse is shown at a higher elevation (303.2) than the outer elipse (296.7). This is top and bottom of the free draining rock layer and the elevations should be switched in the plan drawing. This is the opposite of what is shown in detail 1003. Plan Note 12—do not call out detail 1203 for the 12" slotted pipe. Detail does not apply for this pipe. Provide section view of infiltration facility(detail 1209 missing). Detail 1003: Extend free draining rock layer to at least 6-inches above the slotted PVC pipe. Line sides of infiltration facility with permeable filter fabric, See V5, Ch 5, BMP-T7.20 Provide Detail 1209 for the Section view of the infiltration facility,for review. Stormwater Management Report: SWPPP/TESC plan- Protect infiltration facility from sediment runoff generated during construction. See section II-7.0 of the Geotechnical Engineering Report. MR#5 isn't required under the new stormwater ordinance for the combined sewer area. MR6:Artificial turf is considered by Ecology to be a pollution generating surface (see PGPS definition pg 1073, Ecology manual). Treatment is required for the storm flows from the rubber playground surface that discharge to the infiltration facility. Treatment is not required for flows that discharge to the combined sewer system. Treatment requirements will be dependent on what type of material is used for the playground surfacing. Please provide this information per my previous email. MR 7:The project is in the combined sewer area and adds over 200 sf of net new impervious area. The City's Ordinance related to Stormwater Controls in the Combined Sewer Area applies. See Section 6.10 of the DCSS.