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HomeMy WebLinkAbout013b Wetland Delineation Memo____________________________________________________________________________________ 1 Technical Memorandum To: Tom Murphy Bridger Center, LLC 1450 Cherry Drive Bozeman, MT 59718 From: Lynn Bacon, PWS TerraQuatic, LLC 614 West Lamme Street Bozeman, MT 59715 Date: June 24, 2019 Subject: Bridger Center Wetland and Nonwetland Waterway Delineation ________________________________________________________________________________ 1.0 INTRODUCTION Bridger Center is a vacant 12-acre property located west of Birdie Drive and Boylan Road and east of the East Gallatin River in Bozeman, Montana (SWNWSE Section 31, Township 1 South, Range 6 East; Figure1). The property is comprised of East Gallatin riparian forest and approximately six acres of hay meadow. The Village Green, Bridger Creek Subdivision and Bridger Creek Condominiums border the east and northeast side of the property, respectively. The Story Mill Spur Trail borders the east and north property boundaries. A man-made stormwater/groundwater drainage ditch is located east of the project boundary between the east segment of the spur trail and Boylan Road sidewalk. Groundwater is collected by French drain pipes under the east segment of the spur trail and outlets into the west-middle side of the ditch. Stormwater from the curb and gutters east of the project site empties into the south end of the ditch. The ditch outlets to a stormwater pond north of the subject property and north segment of the spur trail. The 2013, 2018 and 2019 delineations were conducted in various segments of the subject property. The large wetland/upland riparian forest in the southwest corner of the property will not be affected by the proposed work. Wetland/upland boundaries were estimated in this area to satisfy City of Bozeman requirements. The south edge of this riparian forest was officially delineated to define the outer limits of the wetland complex. Areas 50 feet west of the west boundary were included in the delineation investigation area to insure City of Bozeman wetland buffer regulations area incorporated into the proposed development design. The man-made stormwater pond north of the property and the stormwater/drainage ditch east of the property were not delineated given the City of Bozeman does not require 50-foot setbacks along stormwater facilities. However, a 60-foot reach of the ditch was delineated to facilitate permitting for a future utility crossing. Bridger Center Wetland and Nonwetland Waterway Delineation June 24, 2019 ____________________________________________________________________________________ 2 Figure 1. Bridger Center Property, Bozeman, Montana (estimated property boundary is indicated by the red polygon). 2.0 METHODS 2.1 Wetland Delineation Wetlands were originally delineated in late August/early September 2013 using the 2010 Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys and Coast (Version 2.0) (U. S. Army Corps of Engineers [USACE] 2010). At that time the 2013 National Wetland Plant List was used to determine vegetation indicator status (Lichvar et al. 2013). Because the project site took several years to be annexed into the City of Bozeman, the wetland delineation data expired in September 2018. Therefore, on June 6, 2018 the site was revisited to verify wetland boundaries and all previously-collected vegetation data were updated according to the 2016 National Wetland Plant List (Lichvar 2018). Wetlands-1 and 2 remained stable and wetland-3 had increased in size. In October of 2018 wetland-3 was redelineated. The wetland has grown in size because the stormwater pond north of the property is malfunctioning: the pond has less than one foot of free-board because of excess sediment retention and is 80 percent vegetated with cattail (Typha latifolia) and willow (Salix spp.). In April 2019, areas within 50 feet of the west boundary and the south edge of the wetland/upland riparian forest complex were delineated. The neighboring stormwater pond outlet channel and its wetland fringe (wetland-4A) were also redelineated in April, 2019. Wetland/upland boundaries within N Bridger Center Wetland and Nonwetland Waterway Delineation June 24, 2019 ____________________________________________________________________________________ 3 the internal area of the forest complex were estimated in June 2019. Data points (DP) in all years were established within each wetland and adjacent nonwetland area. At each data point wetland indicator data were collected and analyzed using USACE wetland determination data forms. 2.2 Nonwetland Waterways Nonwetland waterways are those scoured portions of river, stream, or ditch-associated habitat that are not vegetated with emergent species (erect, rooted, herbaceous wetland plants). Waterways, whether ephemeral, intermittent, or perennial, typically exhibit scour or areas denuded of vegetation as a result of flowing water over the soil surface. Areas of ponded water with no emergent vegetation are also considered nonwetland areas. The perimeter of all waterbodies and the ordinary high water marks of all channels were surveyed and areas or linear feet quantified. 3.0 RESULTS A wetland (WL) and nonwetland waterway (NWW) delineations was conducted by TerraQuatic, LLC in August/September 2013, June/October 2018, and in April 2019. The aquatic resources delineation map is included in Exhibit A (Appendix A). All wetland features were photographed (Appendix B). The only aquatic feature illustrated on Montana Natural Heritage Program (MNHP 2019) wetland and riparian map is the shallow wetland pond (wetland -1) (Appendix C). Wetland determination data forms are included in Appendix D. 3.1 Wetlands The Bridger Center project site is comprised of 3.26 acres of wetlands within the investigation boundary. Four wetland systems and one nonwetland waterway were delineated. Identification number, wetland acreages, data point number, and general characteristics of these wetland features and nonwetland waterways are listed in Table 3.1. Wetland-1 is a diverse palustrine emergent (PEM) community with an aquatic bed (less than 2-foot deep shallow open water). The west edge of wetland-1 forms the east edge of the wetland-2 wetland/upland riparian complex. This east boundary line was “informally” delineated to satisfy City of Bozeman wetland regulation requirements. A formal delineation, i.e. creation of data points and conducting a formal line survey, of this interior area would be extremely difficult because of its jungle characteristics. Because no disturbance will occur in this area, the aerial delineation was deemed adequate to satisfy City regulations. The informal delineation was conducted by traversing wetland/upland boundary lines while scribing the limits of dominant hydrophytic vegetation communities on an aerial photograph. The west edge of wetland-1 will not be disturbed by the proposed development. Wetland-2 is a palustrine scrub-shrub (PSS) community within the southwest corner of the subject property. The east edge of this wetland/upland riparian complex is defined by the west edge of wetland-1. Internal wetland/upland boundaries were unofficially delineated; no impacts are proposed within the interior of this riparian complex. The interior riparian complex will be preserved for wildlife habitat and remain undisturbed. Bridger Center Wetland and Nonwetland Waterway Delineation June 24, 2019 ____________________________________________________________________________________ 4 Table 3.1. Bridger Center Aquatic Resources Delineation Summary Wetland (WL) Acreage Wetland Data Point Cowardin Type1 Likely JD Status2 Hydric Soil Indicators3 Hydrologic Source Description and/or Dominant Vegetation Species WL-1 1.11* DP-1w PEM Yes F3 groundwater (likely East Gallatin aquifer) reed canary grass (Phalaris arundinacea, FACW), beaked sedge (Carex utriculata, OBL), woolly sedge (C. pellita, OBL), wheat sedge (C. atherodes, OBL), round-fruit rush (Juncus compressus, OBL), Baltic rush (J. balticus, FACW), dagger-leaf rush (J. ensifolius, FACW), chairmaker’s club-rush (Schoenoplectus americanus, OBL), spreading bent (Agrostis stolinifera, FAC), broad-leaf cat-tail (Typha latifolia, OBL), common spike-rush (Eleocharis palustris, OBL), sandbar willow (Salix exigua, FACW), alder (Alnus sp.) WL-2 1.87* DP-2w PSS Yes F3 groundwater (likely East Gallatin aquifer) alder, red-osier dogwood (Cornus sericea, FACW), spreading bent, reed canary grass WL-3 0.22 DP-3w PEM Unknown Other groundwater (from malfunctioning off-property stormwater basin) spike-rush, Kentucky bluegrass, Nebraska sedge (C. nebrascensis, OBL), field meadow-foxtail (Alopecurus pratensis, FAC) WL-4 0.01 DP-4w PSS Yes off-property stormwater ditch (NWW-1) fringe Sandbar willow, quaking aspen (Populus tremuloides, FAC), knotweed (Persicaria maculosa, FACW), leafy tussock sedge (Carex aquatilis, OBL) WL-4a 0.05 DP-4w-1 PSS Yes F6 off-property stormwater pond outlet (fringe along NWW-1a: collects water from stormwater ditch NWW-1/WL-4 system) balsam popular (Populus balsamifera, FAC), red-osier dogwood (no emergent vegetation) TOTAL 3.26 Nonwetland Waterway Acreage6 Linear Feet6 - Likely JD Status2 - Hydrologic Source Notes NWW-1 0.0007 30 - Unknown - street and french drain stormwater OFF PROPERTY: connects to the East Gallatin River NWW-1a 0.0003 75 - Unknown - stormwater collection pond (from NWW-1 channel) connects to the East Gallatin River 1 PEM-Palustrine Emergent; PSS-Palustrine Scrub-Shrub (Cowardin et al. 1979; MNHP 2018) 2 USACE makes the final jurisdictional (JD) determination. 3 F3 – Depleted Matrix; F6-Redox Dark Surface; Other – see USACE Data Forms for reasoning. * Areas estimated based on “informal” wetland determination boundaries inside of the wetland/upland riparian complex. Bridger Center Wetland and Nonwetland Waterway Delineation June 24, 2019 ____________________________________________________________________________________ 5 Wetland-3 is an isolated PEM wetland. This wetland is surrounded by upland and has grown at least 100 percent in five years because of groundwater influences from the malfunctioning and unmaintained stormwater basin north of the property. The basin is choked with sediment and at least 80 percent vegetated with willows and cattail. Wetland-3 is in close proximity (50 feet) to the stormwater basin outflow that connects to the East Gallatin River. Wetland-4 is the PSS fringe along the stormwater/drain ditch located along the east side of the subject property. The ditch enters the malfunctioning stormwater basin north of the property. Wetland-4a is the fringe along the stormwater basin outflow. 3.2 Nonwetland Waterways NWW-1 is the stormwater/drain ditch west of Boylan Road and the property boundary and NWW-1a is the stormwater basin outlet channel. The stormwater conveyance system connects to the East Gallatin River. NWW-1 was delineated in the event a foot bridge is required at this location. 4.0 SUMMARY An estimated 3.26 acres of wetlands and 75 feet of stormwater channelbed occur within the subject property. Off property 30 feet of stormwater/drainage channelbed is located immediately east of the property. No MT310 would be required to impact either of the channelbed because they are not perennial or intermittent streams but arise from stormwater collection. A Section 404 Permit would be required to impact all jurisdictional features; it is unknown if the USACE/EPA would qualify wetland-3 or any of the stormwater features (wetlands-4/4a) as jurisdictional. A site visit will be scheduled during the summer of 2019 to make these determinations. Noxious Weed control has been conducted for the last several years and is ongoing. Bridger Center Wetland and Nonwetland Waterway Delineation June 24, 2019 ____________________________________________________________________________________ 6 5.0 REFERENCES Cowardin, L., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. FWS/OBS-79/31. USDI Fish and Wildlife Service. Washington, D.C. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87-1. Vicksburg, MS: U.S. Army Engineer Waterways Experiment Station. Site accessed December 2012: http://el.erdc.usace.army.mil/wetlands/pdfs/wlman87.pdf. Lichvar, R. W. 2013. National Wetland Plant List: 2013 Wetland Ratings. Phytoneuron 2013-49:1- 241. July 17, 2013. ISSN 2153 733X. Lichvar, R.W., M. Banks, W.N., W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016 Wetland Ratings. Phytoneuron 2016-30:1-17. Published 28 April 2016. ISSN 2153 733X. Montana Natural Heritage Program (MNHP). 2019. Wetland and Riparian Mapping http://mtnhp.org/mapviewer/?t=8 . U.S. Army Corps of Engineers (USACE). 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0), ed. J.S. Wakely, R. W. Lichvar, and C. V. Noble. ERDC/EL TR-10-3. Vicksburg, MS: U.S. Army Engineer Research and Development Center. U.S. Department of Agriculture (USDA). 2019. Natural Resources Conservation Service Soil Survey Geographic (SSURGO) Database for Gallatin County Area, Montana. Site accessed April 2019: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx . APPENDIX A __________________________________________________________________ AQUATIC RESOURCES DELINEATION MAP __________________________________________________________________ APPENDIX B __________________________________________________________________ WETLAND PHOTOGRAPHS __________________________________________________________________ Photo 1. Wetland- 1; view south. Photo 2. North edge of wetland-2; view southwest. Wetland boundary is inside the shrub community beyond the edge of the grass community. Photo 3. South edge of wetland-2; view west. Wetland boundary is at edge of area seeded area where old tires and metal junk were removed in the fall of 2018. Photo 4. Stormwater basin within the southwest corner of the subject property; view northwest. Area surveyed, no work will be conducted in this area and no City of Bozeman setbacks are required along man-made features. Photo 5. Wetland-3; view west. Photo 6. Wetland-4, fringe along NWW-1, the stormwater/groundwater drainage ditch adjacent to Boylan Road; view east. The flags in front are on top of the upland ditch bank (DP-4u). The ditch bed in photo center is filled with leaves (fall 2018). Photo 7. Wetland-4a, fringe along NWW-1a, the outflow swale for the stormwater pond north of property (view south). APPENDIX C _________________________________________________________________ USACE WETLAND DETERMINATION DATA FORMS __________________________________________________________________ APPENDIX D __________________________________________________________________ MNHP Wetland and Riparian Map and SSURGO Soil Report __________________________________________________________________ Figure D.1. Montana Natural Heritage Program wetland and riparian map (2019); red polygon is approximate location of property boundary. Figure D.2. Soil map (SSURGO 2013); red polygon is approximate location of property boundary. Warning: Soil Map may not be valid at this scale. You have zoomed in beyond the scale at which the soil map for this area is intended to be used. Mapping of soils is done at a particular scale. The soil surveys that comprise your AOI were mapped at 1:24,000. The design of map units and the level of detail shown in the resulting soil map are dependent on that map scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Tables — Hydric Rating by Map Unit — Summary By Map Unit (AOI-Area of Interest) Summary by Map Unit — Gallatin County Area, Montana (MT622) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 407A Sudworth-Nesda loams, 0 to 2 percent slopes 2 7.2 17.1% 509B Enbar loam, 0 to 4 percent slopes 10 0.5 1.2% 512B Enbar-Nythar loams, 0 to 4 percent slopes 35 19.7 46.4% 542A Blossberg loam, 0 to 2 percent slopes 95 7.3 17.3% 606A Bandy-Riverwash-Bonebasin complex, 0 to 2 percent slopes 65 7.5 17.7% SLF Sanitary landfill 0 0.2 0.4% Totals for Area of Interest 42.4 100.0% Description — Hydric Rating by Map Unit This rating indicates the proportion of map units that meets the criteria for hydric soils. Map units are composed of one or more map unit components or soil types, each of which is rated as hydric soil or not hydric. Map units that are made up dominantly of hydric soils may have small areas of minor nonhydric components in the higher positions on the landform, and map units that are made up dominantly of nonhydric soils may have small areas of minor hydric components in the lower positions on the landform. Each map unit is designated as "hydric," "predominantly hydric," "partially hydric," "predominantly nonhydric," or "nonhydric" depending on the rating of its respective components and the percentage of each component within the map unit. "Hydric" means that all components listed for a given map unit are rated as being hydric. "Predominantly hydric" means components that comprise 66 to 99 percent of the map unit are rated as hydric. "Partially hydric" means components that comprise 33 to 66 percent of the map unit are rated as hydric. "Predominantly nonhydric" means components that comprise up to 33 percent of the map unit are rated as hydric. "Nonhydric" means that none of the components are rated as hydric. The assumption here is that all components of the map unit are rated as hydric or nonhydric in the underlying database. A "Not rated or not available" map unit rating is displayed when none of the components within a map unit have been rated. Hydric soils are defined by the National Technical Committee for Hydric Soils (NTCHS) as soils that formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part (Federal Register, 1994). Under natural conditions, these soils are either saturated or inundated long enough during the growing season to support the growth and reproduction of hydrophytic vegetation. The NTCHS definition identifies general soil properties that are associated with wetness. In order to determine whether a specific soil is a hydric soil or nonhydric soil, however, more specific information, such as information about the depth and duration of the water table, is needed. Thus, criteria that identify those estimated soil properties unique to hydric soils have been established (Federal Register, 2002). These criteria are used to identify map unit components that normally are associated with wetlands. The criteria used are selected estimated soil properties that are described in "Soil Taxonomy" (Soil Survey Staff, 1999) and "Keys to Soil Taxonomy" (Soil Survey Staff, 2006) and in the "Soil Survey Manual" (Soil Survey Division Staff, 1993). If soils are wet enough for a long enough period of time to be considered hydric, they should exhibit certain properties that can be easily observed in the field. These visible properties are indicators of hydric soils. The indicators used to make onsite determinations of hydric soils are specified in "Field Indicators of Hydric Soils in the United States" (Hurt and Vasilas, 2006). References: Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service. U.S. Department of Agriculture Handbook 436. Soil Survey Staff. 2006. Keys to soil taxonomy. 10th edition. U.S. Department of Agriculture, Natural Resources Conservation Service.