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Home My WebLink AboutHANSEN FARM - PDP - PDP170036 - SUBMITTAL DOCUMENTS - ROUND 4 - WETLANDS DOCUMENTSSeptember 21, 2018 Jeff Mark, President The Landhuis Company 212 N. Wahsatch Ave., Suite 301 Colorado Springs, CO 80903 RE: Wetland and Other Waters of the U.S. Delineation for the Hansen Property in Fort Collins, Colorado Jeff: This letter report is submitted to document my delineation of wetlands along the unnamed irrigation ditch (south ditch) on the Hansen Property southern border. The wetland survey was completed to address City of Fort Collins information requirements for possible impacts to wetlands in the south ditch from proposed pedestrian and street crossings over the ditch and installation of an enlarged and upgraded culvert within the south ditch. The objective of the delineation work was to fulfill the requirements of Section 404 of the Clean Water Act regarding the delineation of wetlands and other potential Waters of the U. S. prior to proposed development activities, as well as to address City of Fort Collins’ wetland delineation requirements. Survey Methodology Prior to initiation of field delineation work, NRCS soils mapping of the project site were reviewed to determine the characteristics of soils overlying the project area. Potential hydric soils were identified for evaluation during the field delineation work. Wetland delineation and sampling work for wetlands and unvegetated channel features within the south ditch were completed using the methods and techniques specified for "routine on-site delineations" in the publication, Corps of Engineers Wetlands Delineation Manual (USACOE 1987), and supplemented by the document, Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plains Region (Version 2.0) (USACOE 2010). The south ditch portion of the project area was evaluated and potential wetland, transition zone, and upland vegetation communities were identified. Using the three- parameter approach via test hole characteristics, the wetland/upland boundaries were flagged. Five formal sample point locations (H-D1, H-D2, H-D3, H-D4, and H-D5) were established to characterize the wetland area and adjacent uplands. The sample point locations are depicted on the attached wetland delineation map. At each sample point, percent total cover of dominant plant species was estimated. Species were then classed as OBL (obligate wetland species), FACW (facultative wetland species), FAC (facultative species), FACU (facultative upland species) or UPL (upland species), based on the USDA, NRCS 2012 National Wetland Plant List (http://plants.usda.gov/wetland.html). Soil and hydrologic data were also collected to determine the presence or absence of wetlands at each sample point. A formal field data sheet was completed for each sample point. The wetland/upland boundaries were flagged with pink fluorescent tape and sample points were marked with an orange pin flag tied with pink fluorescent tape for subsequent surveying work. Boundaries of Other Waters of the U. S. (unvegetated active channel) were flagged with blue tape, which also defined the lower wetland boundary. Adjunct test holes were also dug, where appropriate, to gain additional vegetation, soil, and hydrologic information used to aid in the characterization of wetlands, uplands, and transition zones. Data sheets were not completed for test holes. Northern Engineering of Fort Collins surveyed the wetland and Other Waters of the U. S. boundaries after the delineation was completed. The results of the field delineation are summarized in the following section. A location map, wetland and sample point photos, copies of the field data sheets, and wetland map exhibits are included as attachments. Wetland map exhibits are not provided for the two pedestrian crossings since these crossing will span the entire south J. Mark 9/21/2018 Page 2 of 3 ditch and not impact wetlands within the ditch at these crossings. Sample points H-D1 and H-D2 were established at the west pedestrian crossing so their locations are not shown on the three wetland map exhibits provided. Results NRCS mapping for Larimer County indicates Nunn clay loam; Nunn clay loam, wet; Fort Collins loam; and Caruso clay loam are the four soil map units in the project area. Nunn clay loam, wet and Caruso clay loam are classified as hydric soils by the NRCS. The small, isolated wetland depression previously delineated on the property is within the Caruso clay loam soil-mapping unit. No vegetation or hydrologic characteristics of wetlands were found within the Nunn clay loam, wet unit. The majority of the project area is composed of upland alfalfa grass hayfield areas that are associated with the Fort Collins loam, Nunn clay loam, and Nunn clay loam, wet soil-mapping units. The south ditch is within Fort Collins loam and Nunn clay loam mapping units; neither of these is classified as hydric soils by the NRCS. Wetlands associated with the south ditch are confined within the ditch embankments and are characterized by relatively narrow (1 to 3 feet wide), intermittent strips of wetland-associated vegetation. In some ditch segments with steep banks, no wetland vegetation is supported and there is an abrupt transition from ditch banks supporting upland vegetation to the active ditch channel supporting no vegetation. Dominant wetland vegetation species supported within the south ditch are comprised primarily of reed canarygrass (Phalaris arundinacea) and Emory sedge (Carex emoryi), with a few small pockets of sandbar willow (Salix exigua). Sample point H-D1 and H-D3 were established to characterize wetlands within the south ditch embankments, while sample point H-D2 and H-D4 were established characterize uplands adjacent to the south ditch. Adjacent uplands are dominated by smooth brome (Bromus inermis), field bindweed (Convolvulus arvensis), alfalfa (Medicago sativa), and crested wheatgrass (Agropyron cristatum). Sample point H-D5 was established in a clump of sandbar willow growing outside of the top of bank of the south ditch. Sandbar willow, a wetland plant, was dominant in the overstory but the understory supported only upland associated plants (smooth brome, Canada thistle, and Virginia creeper). Evidence of wetland hydrology and hydric soils were also lacking at H-D5 so this area was classified as upland. Table 1 provides a summary of each sample point. TABLE 1 Summary of Hansen Property - South Ditch Wetland and Upland Sample Point Characteristics Sample Point Dominant Species Hydric Soil Indicator(s) Primary & Secondary Hydrology Indicator(s) COE Wetland H-D1 Phalaris arundinacea - FACW Carex emoryi -OBL F3 B3, C3, D2 PEM1 H-D2 Bromus inermis - UPL Convolvulus arvensis - UPL none none no H-D3 Salix exigua - FACW Carex emoryi - OBL F3 A3, D2 PEM1 H-D4 Bromus inermis - UPL Medicago sativa - UPL Agropyron cristatum - UPL none none no H-D5 Salix exigua - FACW Bromus inermis - UPL Cirsium arvense - FACU none none no J. Mark 9/21/2018 Page 3 of 3 Jurisdictional Considerations Water in the south ditch flows in a southeast direction along the southern property boundary of the Hansen Property. There is a head gate at the southeast corner of the property where the ditch goes underground. The gate structure has two openings, one facing south and one facing east. The south opening is blocked, but the east-facing opening is open and carries water flow from the ditch. The area east of Timberline Road between Trilby Road and Mail Creek was searched, and no culvert opening could be found where water flow was being discharged similar to the quantity observed at the south ditch head gate structure on the Hansen Property. I was able to talk with David Maitland (the end user of irrigation water in the south ditch) and he confirmed that all the water in the south ditch flows by pipe from the Hansen Property to his property (7100 Silver Mist Lane) where it is all utilized as irrigation for his fields and does not openly connect to Fossil Creek Reservoir. Therefore, it is highly unlikely any of his irrigation water finds it’s way into the Reservoir, and the U. S. Army Corps of Engineers would not classify water in the south ditch as jurisdictional. This conclusion is further confirmed by the fact that the U. S. Army Corps of Engineers has previously deemed that flow in the south ditch was not jurisdictional for the development of the Latter Day Saints Temple at the southeast corner of Timberline Road and Trilby Road. Wetland Impacts Based on the wetland exhibit maps prepared by Northern Engineering (see wetland exhibit attachments), the two road crossings and culvert upgrade would impact 432 square feet (~0.01 acre) of wetlands and 603 square feet (0.014 acre) of open water channel (Other Waters of the U. S.) for a total loss of 0.024 acre of wetlands and Other Waters of the U.S. This is well under the 0.1 acre of disturbance the U. S. Army Corps of Engineers uses to trigger the requirement for a request for a Nationwide Permit. The culvert upgrade would have no impact on upland stands of sandbar willow growing outside the ditch embankments (see Sheet 1). Also, as indicated at the beginning of this report, the two proposed pedestrian bridges would completely span the south ditch and have no impact on wetlands within the ditch. Sincerely, T. Michael Phelan Wildlife and Wetland Consulting attachments: location map, photos, data sheets, and wetland map exhibits pc: K. Turner, The Birdsall Group TH SAMPLE POINT H-D5 34 SF SHEET 1 OPEN WATER WETLAND WETLAND/OPEN WATER TO BE REMOVED KEYMAP B M M GAS F.O. MM M F.O. 16" W TIMBERLINE RD ZEPHYR RD NORTH ( IN FEET ) 0 1 INCH = 20 FEET 20 20 SHEET 1 SHEET 2 SHEET 3 PED BRIDGE PED BRIDGE ENGINEER ING N O R T H E RN 291 SF 347 SF SHEET 2 OPEN WATER WETLAND WETLAND/OPEN WATER TO BE REMOVED KEYMAP B M M GAS F.O. MM M F.O. 16" W TIMBERLINE RD ZEPHYR RD NORTH ( IN FEET ) 0 1 INCH = 20 FEET 20 20 SHEET 1 SHEET 2 SHEET 3 PED BRIDGE PED BRIDGE ENGINEER ING N O R T H E RN TH TH SAMPLE POINT H-D4 141 SF 222 SF SAMPLE POINT H-D3 OPEN WATER WETLAND WETLAND/OPEN WATER TO BE REMOVED KEYMAP B M M GAS F.O. MM M F.O. 16" W TIMBERLINE RD ZEPHYR RD NORTH ( IN FEET ) 0 1 INCH = 20 FEET 20 20 SHEET 3 SHEET 1 SHEET 2 SHEET 3 PED BRIDGE PED BRIDGE ENGINEER ING N O R T H E RN