3003 W CASINO RD BLDG 40-58 2025-07-25

bib 40-58 CWC Building — [MM006] City Stormwater Meeting Minutes 5 0 Y E A R s ' + Jane Z.stated by the city that in order to stay within the currently permitted condition,this 0.8 acres of pervious area affected in subbasins 38 and 59 of the EIS report would need to be accounted for elsewhere I on site. • This pervious area could be reserved in another subbasin within the same overall basin. Subbasin 88 was identified as an option because while it is designed to be 100% impervious,there are some pervious areas within the subbasin today.These pervious areas would be reserved in the design and the impervious percentage of subbasin 88 would be modified appropriately. ' ■ The subbasins that did not drain to the Powder Mill Gulch Detention Pond were discussed (subbasins 79 and 80). + As part of previous studies (1988)this area had an assumed impervious coverage and was assumed to drain to the Powder Mill Gulch Detention Pond. + As part of the 1991 EIS study, it was determined that these areas drained to the West Detention Pond and the Fluke Pond A. • Jane Z. identified misunderstandings from the Fluke calculations in the 1991 EIS which were corrected in the subsequent design and permit submittals for the 40-87 and 40-88, and parking lot N7. Ultimately this will affect the basin lines and discharge points for subbasins 79 and 80. • A final approval letter was mailed was dated March 16, 1992 addressing the Fluke pond and their I designs. • 1984 EIS KPFF design report for Fluke ponds and their modifications needs to be accounted for. • Jane Z. will research the permitted Engenious report and provide a copy. + After the 1991 EIS study, a parking lot was constructed in this area for the 40-88 and 40-87 buildings.This parking lot contains underdrains designed to help recharge existing sink holes in the area. + Jane Z. expressed concern as to whether the underdrains would be impacted. Andrew L. stated that they do not expect to be impacting drainage runoff to the underdrains. + It was discussed that the basin lines shown on the 1991 EIS weren't entirely clear on where they fell in relation to the parking. + Jane Z. stated that the intent should be to provide the same amount of flows to the same outfalls in the post development condition, as in the pre development condition. • She is most concerned about increasing discharge to the Fluke "B" pond (AKA—West Detention Pond).This area is the most subject to erosion because of the difference in elevations. ■ Cory C. asked whether the City would like any calculations performed as part of the report. + Jane Z. stated that they would prefer to not receive any calculations, and would prefer everything be validated through narrative and charts. ■ Cory C. asked if there was an application that would need to be submitted with the report. + Jane Z. stated there was not. ■ Jane Z. stated that they would like to keep an open line of communication throughout the process to simplify everything. BRPH agreed. + Boeing stated that they would like to be copied or notified of any communication. ■ Jane Z. stressed importance to maintain runoff within the respective subbasins during construction. IAttachments,Exhibits ■ Basin Impact Exhibit \c06956.001.00-boeing-40-58 cwfc\2.4-meeting minutes, tele-memos, project memos\weekly site update meetings\(2014-04-03) mm006-40-58 city stormwater meeting minutes.docx I