5.3. & 5.4. PCSR 06-09-2009 - Laserfiche WebLink

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• The surface water runoff from the final covered landfill surface will be routed by drainage terraces that are graded into the waste structure that direct surface water to gabion-lined downslope structures. From the downslope structures, the water is subsequently routed by perimeter ditching to two sedimentation basins located on the southeast and southwest corners of the SDA. The drainage routing features have all been sized to minimize the erosion from the site. In addition to permanent control structures, the site also utilizes temporary erosion control features, such as silt fencing, biologs, and erosion control matting to minimize erosion from the site. Portions of the final closure area are covered with erosion control matting upon closure to minimize erosion from the newly graded surfaces. Stormwater generated from the site will be discharged via a storm sewer system, under the exterior roadway to the north end of the SDA, then west under the City Trail into a wetland upstream of the Rice Lake wetland complex. The discharge point will be onto property owned by the ERL. Discharge from P-1 to the wetland west of the site has been designed to minimize impacts by limiting bounce in the wetland, restricting flow rates, and treating stormwater prior to discharge in accordance with applicable permits. This wetland receiving discharge from the site currently has two existing channel outlets, both of which eventually drain into Rice Lake. The north channel outlet, currently located on property owned by Elk River Landfill will be utilized as the outlet channel for the southwest storm water pond. The channel outlet will be re-excavated to match the elevation of the more southerly outlet to ensure that flows through the south outlet onto the adjoining property are not significantly increased from the exiting condition. • Routine maintenance of the drainage control structures are initiated in response to general inspections or inspections prompted by a heavy rain. The sedimentation ponds will be cleaned periodically to maintain their optimum settling capacity. 1.2.7 LANDFILL CLOSURE CONSTRUCTION Final grading and closure of the landfill will be in accordance with the Engineering Plans prepared for the ERL and submitted as part of the permitting documents. The grades of each sequenced closure phase will provide a uniform surface with adjacent phases to facilitate surface water drainage. Each of the phased closure construction sequences will be certified by a Professional Engineer registered in the State of Minnesota, stating that the landfill closure was constructed in accordance with the approved plan, ordinances and license conditions with any exceptions explained. Upon completion of final closure of the SDA, the City of Elk River, the MPCA, and Sherburne County will be provided with a closure certification record by a Professional Engineer registered in the State of Minnesota that the ERL has been closed in accordance with the approved plans and requirements with all exceptions noted and explained. Additionally, an estimate of the volume of waste types accepted at the facility and a description of what the facility had been used for with a certified plat survey of the property by a Land Surveyor registered in the State of Minnesota. Sherburne County will record a deed notation for the property that will indicate what the property had been used for with pertinent details. • Elk River Landfill SDA ~ ~ BOnEStI'00 ~ilWencl< Section 1-7 Land Use Application .,. „~~„~,,,,,~