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The maximum allowable velocity in vegetated swales is 0.9 � <br /> feet per second. � <br /> The Manning�s equations, with an "n" value of 0.20, is to be <br /> used to calculate the averaqe flow velocity in the 'vegetated <br /> swale. <br /> Vegetated swales are to be desiqned with a trapezoidal cross✓ <br /> section, with a bottom width be*ween one and eight feet. <br /> The maximum allowable depth in vegetated swales is 2 inches � • <br /> for swales l�cated in landscaped, reqularly mowed areas; 4 <br /> inches for grass swales located in infrequently mowed areas; <br /> and 6 inches for emergent swales. <br /> The following information is required for City review and / <br /> approval of vegetated swales: � <br /> 1) design flow calculation <br /> 2) velocity and flow depth calculations <br /> 3) bypass sizing calcu2ations <br /> 4) copy of site plan showing the contributing area <br /> 5) calculation of the hydraulic residence time in <br /> eac� swale <br /> AT.A� RBVIE1i COMMENTS <br /> Veaetated swales: `� <br /> Spot elevations in the bottom of the swale should be given <br /> at the head of the swale, at the swale eutlet, and at <br /> approximately 50 foot intervals along the length of the <br /> swale. <br /> The following requirements and drawings from the City's <br /> Design and Construction Standards and Specifications should <br /> be included on both the drainaqe plans and on any landscape <br /> plans for the area: <br /> 1) The City's vegetated swale construction v <br /> requirements from section 4-12.4 (2) . v <br /> 2) The veqetated swale plantinq r ��rements, <br /> includinq the vegetated swale �� �d and wetland 'v" <br /> plant lists from section 4-12.3. <br /> 3) The swale cross sections and plan view shown in � <br /> City standard drawing #419. <br /> 4) The vegetated swale maintenance requirements from ' <br /> section 4-12.5 of the City's standards. <br />