Information for File # MMJ; Methodist Hospital Flood Storage Mitigation and Wetland Enhancement Project

Transcription

1 Information for File # MMJ; Methodist Hospital Flood Storage Mitigation and Wetland Enhancement Project Applicant: Park Nicollet, Attn: Robert Riesselman Corps Contact: Melissa Jenny Address: 180 East Fifth Street, Suite 700, St. Paul, Minnesota Melissa.m.jenny@usace.army.mil Phone: (651) Primary County: Hennepin Section: 20 Township: 117 N. Range: 21 W. Information Complete On: 5/20/2016 Posting Expires On: 5/30/2016 Authorization Type: LOP-05-MN This application is being reviewed in accordance with current practices for documenting Corps jurisdiction under Section(s) 9 & 10 of the Rivers and Harbor Act of 1899 and Section 404 of the Clean Water Act. If an approved jurisdictional determination is completed as part of the review process for this application, a copy will be posted on the St. Paul District web page at the following link: PROJECT BACKGROUND, DESCRIPTION AND PURPOSE: The primary purpose of the project is to provide required flood storage mitigation for a proposed floodwall that would decrease the flood storage capacity within developed areas of the Park Nicollet Methodist Hospital. A secondary purpose is to enhance the herbaceous vegetation community within the wetland which is currently composed of nearly monotypic invasive cattail (Typha angustifolia and T. X glauca). The project is needed since flooding potentially impacts parking areas, internal roads and walking areas on the west side of the hospital campus. The floodwall would be constructed along the west boundary of the hospital campus and a portion of the wetland complex immediately to the west would be excavated to provide flood storage capacity to mitigate the decrease in flood storage that would result from the floodwall construction. The flood storage loss from floodwall construction has been determined to be 1,175 cubic yards based on volume calculations made using established normal water elevations and 100 year floodplain elevations from hydrologic modeling previously conducted. The wetland excavation/enhancement project as proposed would provide approximately 2,500 cubic yards of new flood storage as floodplain mitigation. 1

2 NAME, AREA AND TYPES OF WATERS (INCLUDING WETLANDS) SUBJECT TO LOSS: The project would involve excavation and grading activities that would result in the discharge of dredged material into approximately 2.9 acres of existing seasonally flooded basin, fresh wet meadow, and floodplain forest type wetland. The project would involve converting the existing degraded wetland basin to a higher quality wetland with varied wetland communities including: seasonally flooded basin, wet meadow, shallow marsh, deep marsh, shrub swamp and forested wetland type wetland, as shown on the enclosed figures. ALTERNATIVES CONSIDERED: The applicant considered constructing the floodplain mitigation site in an upland area, but there is not adequate upland located adjacent to the hospital and Minnehaha Creek that could provide the flood storage replacement needed as a result of the floodwall construction project. The applicant is working closely with the Minnehaha Creek Watershed District (MCWD) in order to comply with their regulatory requirements; the MCWD supports the proposed floodplain mitigation and wetland enhancement project. COMPENSATORY MITIGATION: The applicant has not proposed compensatory mitigation for this project. The application states: The proposed work will include the enhancement of the vegetation community in the wetland and will maintain or improve wetland functions ( functional lift ). Compensatory mitigation is not proposed since the proposed work will not result in a loss or degradation of the quality of wetland. Drawings: See enclosed, labeled as MMJ, Figures

3 MMJ, Posting figure 1 R21 S8 R21 S9 T29 R24 S31 R21 S18 R21 S17 R21 S16 T28 R24 S6 Site Location R21 S19 R21 S20 R21 S21 T28 R24 S7 R21 S30 R21 S29 R21 S28 T28 R24 S18 Wright County Anoka County Hennepin County Feet± Minneapolis South 7.5 Minute Quadrangle (USGS: 1973) R21 S31 R21 S32 T28 R24 2,000 1, ,000 R21 S33 Carver S19 Dakota County Scott County Copyright: 2011 National Geographic County Society, i-cubed Path: L:\5981\01\mxd\Figure 1-Site Location Map.mxd Date: 5/3/2016 Time: 7:46:10 AM User: BolWD0186 Site Location Map Figure 1

4 MMJ, Posting figure 2 Proposed Impacted Floodplain Area Floodplain Mitigation/Wetland Enhancement Area 100 Year Floodplain (Elevation ft) Proposed Floodwall Location (1175 CY of Floodplain Impact) Alternate Floodplain Mitigation Location Minneapolis South 7.5 Minute Quadrangle (USGS: 1973) Path: L:\5981\01\mxd\Figure 2-Proposed Floodplain Impacts.mxd Date: 5/3/2016 Time: 7:56:32 AM User: BolWD0186 Feet ± Proposed Floodplain Impacts Figure 2

5 MMJ, Posting figure 3 MN DNR Public Water Inventory Stream MN DNR Public Water Inventory Basin Floodplain Mitigation/Wetland Enhancement Area Unnamed ( W) Unnamed ( W) Minnehaha Creek Unnamed ( W) 2012 Aerial Photograph (Source: MN GEO) Path: L:\5981\01\mxd\Figure 3-MN DNR PWI.mxd Date: 5/3/2016 Time: 8:10:29 AM User: BolWD0186 Feet ± MN DNR Public Water Inventory Figure 3

6 MMJ, Posting figure 4 MCWD FAW Wetland Boundary Floodplain Mitigation/Wetland Enhancement Area E Shallow Marsh Revised NWI-Circular 39 Seasonally Flooded Basin(Type 1) Wet Meadow (Type 2) Shallow Marsh (Type 3) Deep Marsh (Type 4) Shallow Open Water (Type 5) Shrub Swamp (Type 6) Wooded Swamp (Type 7) Bogs (Type 8) Municipal and Industrial Activities Riverine Systems D Floodplain Forest Minnehaha Creek D Floodplain Forest Unknown Aerial Photograph (Source: MN GEO) Path: L:\5981\01\mxd\Figure 4-NWI and MCWD FAW.mxd Date: 5/3/2016 Time: 8:25:05 AM User: BolWD0186 Feet ± NWI and MCWD FAW Figure 4

7 MMJ, Posting figure 5 Wetland Boundary Boardwalk Existing Wetland Vegetation Community Deep Marsh Floodplain Forest Seasonally Flooded Basin/Fresh (wet) Meadow 2012 Aerial Photograph (Source: MnGeo) Feet ± Path: L:\5981\01\mxd\Figurre 5-Existing Wetland Vegetation Communities.mxd Date: 5/3/2016 Time: 8:49:25 AM User: BolWD0186 Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community APR 2016 Existing Wetland Vegetation Communities Figure 5

8 MMJ, Posting figure 6 Wetland Boundary Proposed Work in Wetland Excavation Scrape Vegetation No Disturbance Proposed Excavate Wetlands 1.1 acre Scrape Vegetation 1.5 acre Excavate Channel /Linear Wetlands 0.3 acre 2012 Aerial Photograph (Source: MnGeo) Path: L:\5981\01\mxd\Figurre 6-Proposed Work in Wetlands.mxd Date: 5/3/2016 Time: 11:47:36 AM User: BolWD0186 Feet ± Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community APR 2016 Proposed Work in Wetlands Figure 6

9 MMJ, Posting figure 7 Wetland Boundary Boardwalk Proposed Wetland Vegetation Communities Deep Marsh Shallow Marsh Seasonally Flooded Basin/Wet Meadow Shrub Swamp Floodplain Forest 2012 Aerial Photograph (Source: MnGeo) Path: L:\5981\01\mxd\Figurre 7-Proposed Vegetation Communities.mxd Date: 5/3/2016 Time: 12:51:38 PM User: BolWD0186 Feet ± Source: Esri, DigitalGlobe, GeoEye, i-cubed, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community Proposed Vegetation Communities Figure 7