Laserfiche WebLink
�. � Y2��R :•,eC i �-t rrx� fY� � ^ KCG� C,,� .'Y(-, :--,i �c' • <br />�. _ <br />TO: <br />FItOM: <br />DATE: <br />J�� �c � <br />�;� � � o a�-- <br />M E M O R A N D U M <br />Kirk Brooks <br />Jane Zimmerman <br />June 27, 1994 <br />� ��� � � <br />( V � <br />V ''���C �r �/ 15 <br />. <br />UJ'� ��f��' , <br />� � <br />t3U$JECT: Plan P.eview, SEPA #8-94, Dairy <br />Evergreen Way <br />CALCUI,ATIONS <br />Veaetated swales: <br />Calculetions need to be submitted showing the velocity and <br />dEpth of flow in �he existing swale for the 2 year and 25 <br />year, 24-hour storm peak flows. If velocities will exceed <br />0.9 feet per second in the swale during the 25 year storm, <br />high flow bypassing may be required for some of the area <br />draining to the swale. <br />The residence time in the s•dale for runoff from the Dairy <br />/ QuPen improvements, taking into account off-site runoff, <br />� needs to he calculated. The average residence time, <br />weiqhted by the area draining to each separate inlet point, <br />should be at least 5 minutes for the 7 year, 24-hour storm. <br />� <br />� <br />i/ <br />City standards call for the Manning's equation, with an "n" <br />value of 0.20, to be used to calculate the average flow <br />velocity in the vegetated swale. <br />The maximum allowable depth in emergent vegetated swales is <br />6 inches. <br />PL7�N P.EVIEW CQMMENTS <br />�,eaetatPd swale: <br />The second i�let to the swale n�eds to be moved upstream so <br />that all runoff travels through at least 100 feet of swale. <br />V- The building runoif should be routed to the end of the swale <br />to maximize �he swale's effectiveness in treating the <br />pavement runoff. <br />. <br />