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April 12, 2017 Page 2 Comment 3: Item 13.d — Fish, Wildlife, Plant Communities, and Sensitive Ecological Resources (Rare Features) (Jim Larsen, 651-602-1159) A significant number of natural wetlands and constructed surface water basins will be present on the developed site.. The EAW indicates that Blanding's turtle (E,mydoidea blandingii), a state - listed threatened species has been sighted within the project boundaries. Council staff encourages specifying the utilization of sloping, surmountable curbs for all roadways to be constructed within the development. `1'he use of standard, near -vertical B424 or similar curbing can entrap turtles within roadways as they pass between wetland basins and potential nearby habitat areas, can lead to high mortality rates. This simple design change to use a more gently sloping curb will reduce the fauna mortality risk without impacts to storm water flow, driver and pedestrian safety, or maintenance activities and is consistent with recommended Minnesota Department of Natural Resources guidance presented in EAW Appendix; C. We suggest tine use of Minnesota Department of Transportation Curb and Gutter Design No. S524 or similar design profile. Response: Aside from a 400-foot stretch of access road from 130th Street North, the project is currently designed with surmountable curb and gutter. The project proposer will use Minnesota Department of Transportation Curb and Gutter Design No. 5524, or similar, where surmountable curb and gutter is specified. 2. Minnesota Department of Natural Resources (MnDNR) Comment 1: A significant portion of this project area is within the mapped 100-year floodplain and development will need to meet local and state floodplain regulations. The EAW should provide a more detailed description of how elevations in the existing floodplain will be modified, what compensatory storage will be constructed and where it will be located, and how the project will alter flood flow (determined through hydraulic modeling). Response: The project will meet local and state floodplain regulations. The project proposer has prepared an engineering report to support a FEMA Letter of Map Revision (LOMR), and is currently in the process of coordinating with FEMA and Rice Creek Watershed District (RCWD) staff regarding floodplains on the site. To evaluate floodplain impacts, the developer obtained the RCWD XP-SWMM model for the relevant area. The existing condition 100-year high water level (HWL) was modeled in XP- SWMM. The proposed 100-year high water elevation was also modeled in XP-SWMM using LiDAR and the proposed grading plan. According to the models, the proposed condition high water level at the elevation tie-in location is 0.2 feet higher than the existing high water level. This area has no base flood elevation because it is a Zone A. The development has been modeled in XP-SWMM under existing and proposed conditions to establish a revised effective 1% annual chance floodplain and a proposed 1% annual chance floodplain. Using detailed topography and proposed grading plans, the floodplains are more accurate than the effective FEMA floodplain. In proposed conditions, fill will be placed within the existing floodplain. The proposed site will be graded to establish large ponds (located primarily on the western portion of the project area) so that, despite the fill, there will be more storage and a larger floodplain. The existing high water level will increase by 0.2 feet under K:\03288-040\Admin\Dots\EAW\EAW Responses to Comments 041217.docx