4.4 SR 02-21-2023 - Laserfiche WebLink

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City of Elk River Design Standards Section 2500 — Storm Drainage Design Standards Storm design criteria and standards shall follow the requirements detailed in the Elk River Stormwater Program guide. Minor drainage facilities shall carry the 10-year recurrence runoff flows. Minor facilities include street gutter capaciry, cross-culverts, storm sewers, and swales to the limits of easement and/or right-of-wa� . Materials 1. Pipe for all storm sewer installations shall be reinforced concrete pipe. Reinforced circular pipe shall conform to ASTM C 76 for Wall B pipe. Reinforced Arch pipe shall conform to ASTM C 506. Plastic or HDPE pipe for storm sewer installations in green spaces (side or rear yard) may be considered on an individual basis. 2. Standard curb inlet castings shall be Neenah R-3067-V or appro�red equal. In developments with surmountable curb, the curb at catch basin inlets shall n�pically- transition to a B-type curb as shown on Standard Plate 2005. When inlet castings do not align with a property line and surmountable concrete curb and gutter is being placed, inlet castings may be Neenah R-3501-TB provided written approval is obtained from the City prior to construction. 3. For new developments, stormwater outfall erosion prevention material shall be concrete articulated block (eg. Flexamat) or appro�red equal. 4. Driveway culverts located in city right-of-way shall be concrete or corrugated metal pipe. The culverts must be designed and sized to handle the expected drainage. Minimum allowable size for a driveway culvert shall be 12-inches. 5. Rip-rap shall be Class IV random rip-rap in accordance with Mn/DOT 2511 except that all rip- rap shall be made up of granite. Placement of rip-rap shall be as shown on Standard Plate 2505. 6. Rear yard inlets shall utilize a Neenah R-1733 casting with a type C grate. Ditch inlet cas�ings shall be R-4341-A or R-4342. All manhole and catch basin adjustments shall be Cretex Pro-Ring or approved equal. Manhole and catch basin adjustments shall consist of a�rariery of heights (thicknesses), diameters and shapes all conforming to the following requirements: A. Grade adjustments — The grade adjustments shall be manufactured from ARPRO Expanded Polypropylene (EPP) black, 5000 series meeting ASTM D3575 and ASTM D4819-13; B6D7G4L3M24S2T17W7. The grade adjustments shall be manufactured using a high compression molding process to produce a finished densit�� of 120 g/1 (7.5 pc�. The grade adjustments shall meet or exceed the load rating requirements of AASHTO M306, HS-20 and HS-25. B. "Grade" adjustments may contain either an upper and lower key-wa� (tongue and groove) for vertical alignment and/or an adhesive tYench on the underside with a flat top. C. "Finish" or "Flat" adjustments may either have a keyway (groove) on the underside for vertical alignment and/or an adhesi�re trench with a flat upper surface. These adjustments shall be available in heights (thicknesses) which will allow final adjustments of the frame and cover or grate to within '/4" (one quarter inch) of the specified final elevation. "Finish" adjustments may also have a ke�vay on the upper surface of the inner diameter to facilitate installation of an "Angle" adjustment. D. "Angle" adjustments may either have an upper or lower key�vay (tongue and groove) for vertical alignment and/or an adhesive trench on the underside. When required, the "Angle" OO City of Elk River, Minnesota — All rights reserved 6