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8 <br /> <br />2020 there were a number of questions regarding the proposed developments’ stormwater <br />management plan. Below is a summary of findings and actions to address the questions: <br /> <br />• The site outlets to two private ditches, one in the northwest, and one to the north. There <br />is also a small area of the site that drains to the south. <br />• The proposed project is required to mitigate surface water and address water quality <br />through City, Watershed District and State Rules and Statues. This includes maintaining <br />the existing rate or reducing the rate of runoff from the site, and providing water quality <br />treatment for the proposed development. The project meets the City of Lino Lakes’ <br />stormwater management requirements and RCWD rules. RCWD approved a CAPROC <br />on April 8, 2020. <br />o This project is proposing to reduce rates as detailed in the Stormwater Report, <br />and will utilize stormwater ponding for water quality treatment. The stormwater <br />management plan incorporates existing soils and time of concentrations to <br />calculate the needed ponding systems to mitigate the new impervious surfaces. <br />o The surface water from the new impervious surfaces will be accommodated <br />through three new ponds. Pond 200, located in the middle of the site, will pick <br />up surface water from the south portion of the site and direct it towards Pond <br />100. Pond 100 will pick up surface water from the northwest portion of the site <br />and discharge to the west to an existing private ditch. Pond 400 will receive the <br />remaining surface water and discharge to an existing ditch to the north. <br />o The design includes a standard outlet control structure with pipe outlet. An <br />outlet control structure is a device that holds water back in the proposed pond <br />and then discharges it slowly into the ditch so that the flow to the downstream <br />ditch is less than the existing condition flow into the ditch. <br />o The original design included an outlet pipe to the ditch. The applicant was <br />unable to obtain an easement for the outlet pipe to the ditch as required by the <br />City and RCWD. The applicant revised the design and enlarged the pond to <br />provide additional storage and added a plunge pool dissipater at the discharge <br />location. <br />• Adjacent property owners expressed concerns over the s stormwater runoff from the site <br />and the downstream private ditches. Staff had multiple conversations and Zoom <br />meetings with the property owners to better understand their concerns and explain the <br />existing and proposed conditions. This included an onsite evaluation, reviewing <br />topographic data, record plans, survey, and incorporation of the NorthPointe <br />development drainage plan. The downstream systems appear to be working correctly <br />and the NorthPointe development has reduced the surface water flow to the <br />subwatershed in question. We will continue to work the property owners and provide <br />information and findings. <br />o The adjacent private ditch owners are responsible to perpetuate existing runoff <br />rates and are to maintain the ditch flow through their property. Staff reviewed <br />private ditch requirements with the City Attorney and RCWD staff. <br />o 2019 was a record year for rainwater in Minneapolis-St. Paul area according to <br />the Minnesota DNR Year to Date Precipitation Chart. Soil saturation in the fall <br />of 2019 was similar to a spring snow melt condition where typically the fall is a <br />dryer condition. These conditions have led to standing water due to soil <br />saturation and higher flows in conveyance systems. <br />o We are working with one of the downstream property owner to complete culvert