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RCWD Permit Number 17-121 <br />11. Application fee dated 12-04-17 and received 12-05-17. <br />12. RCWD Review File#17-208R <br />Findings: <br />1. Description—This project proposes the subdivision of an existing 1.88±acre lot into 3 total lots. <br />An existing home located on the lot will remain, while 2 additional lots with single family homes <br />will be created. The existing and proposed impervious area is 0.12 ± acres and 0.34 ± acres, <br />respectively. Approximately 0.75 ± acre of land will be disturbed. Flows onsite will be directed <br />into two rate control basins, before discharging to a large public water wetland (Farrel's wetland), <br />then ultimately Long Lake, the Resource of Concern. The applicant has submitted a$100 <br />application fee which correspond to less than 2.5 acres of land disturbance. <br />2. Stormwater—The applicant is proposing the following rate control BMPs as described below for <br />the project: <br />Proposed BMP Volume Required EOF <br />Description <br />Location <br />Filtration Basin 1 NW Corner of Site Rate Control Only 887.0 <br />Filtration Basin 2 West Side of Site Rate Control Only 889.0 <br />Per Rule C.2(g), the applicant is exempt from the water quality treatment requirement, however <br />the filtration basins are required to meet the rate control requirements of C.7. Based off the <br />submitted geotechnical and soil survey information, the soils on site are primarily loamy fine <br />sands and peat(HSG B/D). Due to the proximity of the adjacent wetland and the groundwater <br />elevation (883.5), infiltration is not considered feasible onsite, thus filtration is acceptable to meet <br />the rate control requirements. The applicant will wrap the drain tile with a course filter aggregate <br />before discharging through an orifice and into the adjacent wetland. Emergency overflow <br />spillways will be stabilized with seed and erosion control blanket. <br />2-year(cfs) 10-year(cfs) 100-year(cfs) <br />Drainage Area <br />Existing Proposed Existing Proposed Existing Proposed <br />West to Public <br />Water Wetland <br />0.62 0.42 2.17 1.72 6.91 5.15 <br />Totals 0.62 0.42 2.17 1.72 6.91 5.15 <br />80%of Existing 0.50 1.74 5.53 <br />The project is located within the Flood Management Zone. The submitted information indicates <br />that the project will not increase peak runoff leaving the site. The highest 100-year water level is <br />located at 888.8 (Basin 1) and the lowest floor opening is located at 893, thus meeting the 2-foot <br />freeboard requirement of Rule C.9 (g). The applicant has met the bounce and inundation <br />hydroperiod standards of Rule C.B. <br />Rice Creek Watershed District Page 3 of 4 1/31/2018