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HomeMy WebLinkAbout004_WR_WetlandRevNarrative North Park-West Wetland Review (22273) Application Narrative Overview This Wetlands Review is associated with a Master Site Plan application for the proposed public infrastructure on the west side of the North Park development area. The Mandeville Creek and its associated wetlands will be impacted by the necessity for Wheat Drive and Cultivar Street to cross the water body. The proposed box culvert crossing structures and associated earthwork will alter the creek bank and channel. The crossings will also disturb adjacent wetlands. Mandeville Creek and its associated wetlands are likely jurisdictional waterbodies. On behalf of the applicant, Weston Solutions Inc. has submitted a joint application to the Gallatin Conservation District (310 Permit), Montana DEQ (318 Authorization), and US Army Corps of Engineers (Section 404 Permit) for the proposed Wheat and Cultivar crossings. Impacted Water Body & Location The water body associated with this application is Mandeville Creek and connected wetlands. The project location includes Parcel Tract 1-B, Parcel 2, and State of Montana Tract as described below. • S36, T01 S, R05 E, C.O.S. 2153A, PARCEL TRACT 1-B, ACRES 52.82 • S36, T01 S, R05 E, C.O.S. 1723, PARCEL 2, ACRES 21.492 • S36, T01 S, R05 E, C.O.S. 3019, ACRES 68.36, LESS LEASED LAND Existing Conditions The project area is bounded to the south and southwest by Interstate 90, to the north by the BNSF railroad, and to the east by Mandeville Creek. The tracts are currently undeveloped but used for agriculture. The northern portion of the project area is owned by the applicant Bozeman TRAX Partners, LLC. The State of Montana DNRC owns the southern portion of the project area, which is leased by Bozeman TRAX Partners, LLC. Mandeville Creek and its wetlands run north-south along the eastern edge of the project area. Mandeville Creek is a perennial stream that runs from the south to north through the proposed project area and continues to flow north, eventually, reaching the East Gallatin River. The creek has a rock substrate and an herbaceous vegetation corridor and is approximately 6-8 feet wide with a bank full depth of 2 feet. The stream slope is relatively flat. A stream crossing for the Proposed Track C is the project location where impacts will occur. North Park-West Wetland Review (22273) Narrative page 2 of 4 Wetland 2 (WL-2) is located adjacent to Mandeville Creek from south of the MRL railroad tracks and the former Redwing Drive in Bozeman (see the included November 2021 Wetland and Waterbody Assessment Report for North Park Development). It is a 1.9-acre depressional emergent, riverine wetland that includes narrow wetland herbaceous fringe along Mandeville Creek with rocky bottom. Wetland boundary generally follows creeping foxtail, red canary grass, red top, and lesser poverty rush. Overall Project Description A Master Site Plan for the North Park east side public infrastructure was previously submitted to and approved by the City of Bozeman (COB Project No. 15273). The North Park-West Master Site Plan (COB Project No. 22273) proposes extending the public infrastructure previously approved for the east side of North Park. Street, water, sewer, and stormwater infrastructure is proposed to extend along Wheat Drive and Cultivar Street crossing Mandeville Creek connecting in a loop on the west side. In addition to public infrastructure, the overall North Park area will include railroad sidings and spurs to service industrial site development and uses supported by other commercials uses. Specific Project Description A crossing culvert for Wheat Drive (which includes a multi-use path) is proposed at one of the Mandeville Creek crossings. To maintain creek flows, the project proposes to install an 88’ long and 5’x18’ concrete box culvert with tapered wing walls, as shown in the attached Draft North Park – West plan sheets. In addition, a new creek alignment is proposed at this crossing to minimize the dimensions of the culvert. This new alignment impacts 594 linear feet of creek channel. A crossing culvert for Cultivar Street (which includes a multi-use path) is also proposed south of the Wheat Drive crossing. To maintain creek flows at this crossing, the project proposes to install a 48.5’ long and 5’x18’ concrete box culvert with tapered wing walls, as shown in the attached Draft North Park – West plan sheets. Both culverts will be lowered 1’ in accordance with Montana Regional Conditions but will match the existing stream bed elevation using streambed material for fill (see cross section view on plan sheets C6.0 and C6.1). Design Alternatives for Avoidance For the road to function as designed within the larger project area footprint and accommodate the city engineering requirements for the larger project development, this alternative is proposed to minimize impacts to Mandeville Creek and associated wetlands will maintain existing flows. This alternative tapered the horizontal road alignment at the culvert crossing to minimize wetland impacts rather than maintain the same street/sidewalk horizontal alignment across the entirety of the roadway. In addition, there are pipelines and utilities existing on the North Park-West Wetland Review (22273) Narrative page 3 of 4 property, so design considerations had to account for impacts to the other existing and future infrastructure that meet City of Bozeman’s specifications. Wetland Impacts This proposed project will be constructed in accordance with general Best Management Practices (BMPs) to control erosion and sedimentation. Stream diversion will be necessary and is being coordinated through the engineer and potential contractor, who are considering the best method: either a temporary pipe through the culvert or a small “holding pool”. The construction activity will likely be during low flows and short in duration to limit potential impacts. Following completion of construction, temporary fill will be entirely removed to an area that has no waters of the United States, dredged material will be returned to its original location, and the affected areas will be restored to pre-construction elevations and revegetated, as appropriate. All practicable efforts have been made to avoid and minimize potential impacts to the wetlands and riparian habitat. However, to install the culverts, complete avoidance of the wetlands was not possible. To minimize impacts this proposed design tapers the horizontal road alignment at the culvert crossings rather than maintain the same street/sidewalk horizontal alignment across the entirety of the roadway. The permanent impacts to the Likely Jurisdictional Wetlands are expected to be approximately 0.33 acres. A portion of those impacts are expected to be negated in the future when the new stream alignment establishes adjacent wetlands. There will be temporary wetland impacts associated with limits of disturbance associated with construction activities. The proposed construction will alter the stream channel alignment at the Wheat Drive crossing so that the creek will be more perpendicular to the crossing. The proposed new alignment will be 594 linear feet (shown on Exhibit A). The creek realignment will have a uniform stream channel width and maintain the same bed and bank height as the existing stream. Clearing and grubbing will be limited to the area necessary for construction of the project. It is expected that the construction area will be a very small footprint, with minimal impacts to vegetation. Any impacted vegetation is expected to re-establish during the growing season. If not, a contractor will be hired with a required warranty period to re-seed and revegetate as soon as practicable with desirable species as recommended by Gallatin County. Description of Materials As shown on plan sheets C6.0 and C6.1 of the included plans, approximately 1,518 cubic yards of permanent fill will be placed in WL-2 for the proposed road crossings. The native fill will consist of fill cuts from the adjacent property. Imported fill, if needed, will be sourced locally. One concrete box culvert with wing walls that will be installed is 88’ long and 18’ wide by 5’ in height and the other concrete box culvert with wing walls will be 48.5-feet long and 18’ wide by 5’ in height. Most of the culvert will be under the stream bed to maintain flows, following the 1’ North Park-West Wetland Review (22273) Narrative page 4 of 4 countersink requirements in the Montana NWP conditions with streambed material to the existing stream bed elevation. Other Wetland Permitting The previous permits have been submitted for the MRL Culvert Extension and Track C Rail Extension projects. These two previous permits and the one being submitted for the Wheat Drive and Cultivar Street Crossings are part of a phased Nationwide Permit 39 for Commercial and Institutional Developments. The MRL Culvert Extension phase has been permitted and construction activities completed under NWO-2022-00136. The Track C Extension phase permit as been submitted but not yet approved. There were additional impacts from the MRL Culvert Extension and Track C Rail Extension projects. Those projects impacted 0.057 and 0.097 acres respectively, so cumulatively the total acres of impact for all three projects are 0.43 acres. As a result of the cumulative impacts, mitigation compensation will be required. Confirmation has been obtained with Eco-Assets to purchase wetland mitigation credits from the Upper Missouri Mitigation Bank.