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Ms. Katie Larsen <br />03/06/2024 <br />Page 3 <br />Lino Lake Tech Center Engineering Review <br />(WSB 3/6/2024) Updated report matches plans for new impervious and BMP grading. <br />Further comments are provided below. <br />2.(WSB 3/6/2024) Applicant to clarify BMP type. It is referenced as both a biofiltration <br />basin and an infiltration basin at various points. <br />3.(WSB 3/6/2024) Applicant to specify access route to proposed BMP. The current site <br />plan appears to require access through an existing BMP or down a retaining wall. <br />4.(WSB 3/6/2024) Applicant to revise CN of disturbed pervious cover in accordance <br />with RCWD Rule C.4(b). <br />5.(WSB 3/6/2024) It is recommended to model the downstream BMP in order to <br />understand potential tailwater effects and impacts to high water levels. <br />6.(WSB 3/6/2024) Exfiltration is not allowed in modeling in order to more conservatively <br />estimate high water levels. <br />7.(WSB 3/6/2024) Applicant to model the constructed BMP overflow. Current modeling <br />indicates that this overflow would be used and impact outflow rates in 100-yr event. <br />8.(WSB 3/6/2024) This review finds the minor increase in outflow rates during 10-year <br />storm event is within modeling error. However, the City will defer to RCWD <br />comments if they find this increase unacceptable. <br />9.(WSB 3/6/2024) Based on pervious area berm flowing to CB 4, a Tc of 10 minutes is <br />more appropriate and might ease pipe capacity limitations. <br />10.(WSB 3/6/2024) Applicant to confirm constructability of CB 4. Current rim and inverts <br />don’t appear to leave enough concrete leg above pipe cutout. <br />11.(WSB 3/6/2024) Applicant to confirm constructability of V-notch in BMP OCS. Detail <br />appears to indicate notch continues up to structure rim, which would impact mounting <br />of skimmer grate. <br />12.(WSB 3/6/2024) Applicant to correct mismatch between V-notch invert shown on <br />plans and model. Plans show invert of 899.5, while modeling has invert of 899.75. <br />13.(WSB 3/6/2024) Applicant to include air gap between roof leader and drainage pipe <br />routing to BMP on the west side of the building.