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Tomas Companies Outdoor Storage Application Narrative Date: 8/14/2023 Page: 5 H:\TOMASCOM_PR\0T7129812\5_Permits\City\3_Tomas Companies Outdoor Storage Stormwater Narrative_City of Lino Lakes.docx Existing Conditions In 2007, RCWD Permit #07-066 was issued for the expansion of an existing parking area and the addition of two rain gardens. The two rain gardens were built to treat the 0.34” rain event over new impervious area, which worked in concert with a shallow “dry” impoundment to treat stormwater quality and rate on site. Grading work was done in recent years to level the soil stockpile, and a gravel surface outdoor storage area was constructed for storing pallets of product (wire stems for tomato plants). The eastern rain garden was filled when the stockpile was leveled. A 0.8-acre area in the southeast corner of the site has been delineated as a Type 1/3 Wetland and details on the methods and results of the delineation can be found in the Wetland Delineation Report. The WCA Boundary Decision #23-083R was issued on 6-1-2023 (attached). Proposed Conditions City land use requirements for outdoor storage areas call for pavement, curb and gutter, lights, fencing and associated features. The current proposal expands the outdoor storage area as shown in the attached plans. This project includes grading, bituminous paving, curb and gutter, connection to existing storm sewer, lighting, landscaping, and stormwater management and treatment. The proposed storage area will expand the existing impervious footprint and include stormwater treatment for the new impervious area. The treatment capacity of the rain garden that was filled in is included in the required treatment volume. The detention provided by the existing shallow “dry” impoundment will also be replaced in the new stormwater pond. See attached Existing and Proposed Drainage Figures for drainage patterns of the existing and proposed site. Floodplain As shown on the FEMA Flood Insurance Rate Map Panel 370 of 450 (Map number 27003C0370E Effective date December 16, 2015), there are no mapped FEMA flood zones within the Tomas Company Parcel. In addition, as shown on the Rice Creek Watershed District viewer there are no RCWD mapped floodplains (2022) within the Tomas Company parcel. Impervious Surface Calculations The full buildout of the 17.93-acre site, as shown in the Anoka County Parcel Viewer ( ID #24-31-22-14- 0002) for the parcel outside of the existing roadway easements on Otter Lake Road and Main Street, must not exceed 14.5 acres of impervious to conform with the regional pond design assumptions of a commercial/industrial site with hydrologic curve number of 91. This curve number has a corresponding impervious percentage of 81%. Existing conditions and proposed conditions include 8.5 acres and 10.8 acres of impervious surfaces, respectively, leaving up to 3.7 acres of impervious surface remaining for future expansion to the full build impervious design.