March 30, 2011 Mr. David Singer Environmental Planner CDOT Region 6 2000 S. Holly Street, Room 200 Denver, Colorado 80222 Subject: Biological Resources Summary for the Proposed Colorado Center Bicycle/Pedestrian Bridge, Denver, Colorado (CDOT Project Number STE 0252-411/17954) (PILAR Master Project Number 2010-0408) Dear Mr. Singer: The HNTB Corporation (HNTB), on behalf of the City and County of Denver (Denver), has contracted with Pinyon Environmental Engineering Resources, Inc. (Pinyon), to provide the Colorado Department of Transportation (CDOT) with documentation in support of a Categorical Exclusion for the above-referenced project. This letter has been prepared to document biological resources within the project area. Project Description The project is located east of Colorado Boulevard and south of East Jewell Avenue (Jewell) in Denver, Colorado (Figure 1). The proposed bicycle/pedestrian bridge (bridge) over I-25 would link pedestrian and bicycle traffic from the neighborhood northeast of I-25 with the transit-oriented development and RTD Light Rail Station at Colorado Center (Colorado Station) (Figure 2) (Perspective Drawing, attached). Ramps to the bridge would be constructed along South Cherry Street (Cherry) and parallel to the existing RTD tracks west of I-25 (Figure 2). The portion of the project along Cherry will be within existing Denver right-of-way (ROW) (Plan Sheet 8, attached). Several temporary and aerial easements will be required from private property owners on the east side of I-25 to accommodate construction. These areas are currently used as parking lots (Photolog). ROW acquisition or permanent easements are required for a bridge pier and the staircase planned near the intersection of Cherry and East Asbury Avenue. An aerial easement will be required over I-25. The ramp west of I-25 will be located on property currently owned by RTD. This property will either be acquired by Denver or and a permanent easement will be obtained.
Mr. David Singer March 30, 2011 Page 2 Methods Pinyon biologist Julia Auckland visited the site on January 18, 2011, to evaluate the project area for biological resources. The project area was assessed for wetlands, weeds, and protected species including federally-listed threatened and endangered species, migratory birds, and black-tailed prairie dogs (Cynomys ludovicianus)(prairie dogs). The project area was walked from end to end. Vegetation was noted and representative photographs were taken. Results The project area is completely paved and devoid of vegetation except for one tree and a mowed weedy area west of I-25 (Photolog). The tree is a honey locust (Gleditsia triacanthos) and could be used by birds for nesting. Common herbaceous species observed included kochia (Kochia scoparia), alfalfa (Medicago sativa), and unknown grasses. Curly dock (Rumex crispus) and field bindweed (Convolvulus arvensis) were also observed, but cover was less than five percent. Since the site visit was done in the winter and the vegetation had been mowed it was difficult to identify all the plant species. There are no wetlands, prairie dogs, or habitat for any state- or federally-listed species. Conclusions 1. The project is in a completely urban area with no wetlands or habitat for state- or federallylisted species. Thus, the project will have no impact on these biological resources. 2. The weedy area west of I-25 would be disturbed by construction and then revegetated with native species (Plan Sheet 18). Remaining project areas will all be paved or landscaped. Therefore, a weed management plan is not needed. 3. The project would require removal of one tree west of I-25 (Figure 2). Per CDOT requirements, this would be mitigated by planting a new tree. This change will be incorporated into the FOR plan set. 4. The Migratory Bird Treaty Act (MBTA) protects migratory birds, their nests, and their eggs (except for pigeons and starlings). There is low potential for birds to nest in the tree that will be removed. In Colorado, most nesting and rearing activities occur between April 1 and August 31. These dates are guidelines and nesting birds are protected at all times. Tree removal activities should be completed between September 1 and March 31. If construction occurs between April 1 and August 31, a preconstruction survey for nesting birds must be completed. Preconstruction surveys for nesting birds should be completed by a wildlife biologist with a minimum of three years experience conducting migratory bird surveys. No construction activities may occur within 50 feet of an active nest and orange construction fencing should be installed (if possible) around active nests to protect them until the nest fails or the young fledge. Pre-construction surveys for nesting birds are valid for five days. If work is not completed within this time, then a new survey is required.
Mr. David Singer March 30, 2011 Page 3 As stated previously, this letter has been prepared to provide documentation of biological resources in the project area in support of a CDOT Categorical Exclusion. Please contact me if you need additional information or have any questions. Sincerely, PINYON ENVIRONMENTAL ENGINEERING RESOURCES, INC. Julia Auckland Biologist Attachments: Figure 1 Figure 2 Perspective Drawing Relevant Plan Sheets (ROW Plan and Landscape Plan) Photolog cc: John Guenther, HNTB (1 copy) James Hamblin, Denver Public Works (1 copy) Lisa Farrell, Denver Environmental Health (2 copies) Terry Ruiter, Denver Public Works (2 copies) Z:\PROJECTS\10973501 Colorado Center Bike Ped Bridge\Biological Resources\Colorado Center Bio Letter Mar 30 2011 FINAL.wpd
m Site ³ Legend USGS 7.5' Topographic Map Englewood, CO 1997 Site 0 750 1,500 Feet Environmental Engineering Resources, Inc. SITE LOCATION Colorado Center Bicycle/Pedestrian Bridge Denver, Colorado Site Location: NW1/4, Section 30, Township 4S, Range 67W, 6th Principal Meridian Filename: Projects\10973501 Colorado Center Bike Ped Bridge\Biological Resources\Fig 1.mxd Job No. 1/09-735-01.8808 Drawn By: MJS Reviewed By: JNA Figure 1 Revision 0
¾½ ¾½ ¾½ ¾½ ¾½ ¾½ ¾½ ¾½ ¾½ East Jewell Avenue Condos Apartments Office Building 25 Apartments South Cherry Street Condos Colorado Center Drive ¾½ Office Building Parking Structure South Frontage Road ¾½ ¾½ ¾½ ¾½ ¾½ qp ¾½ ¾½ ¾½ ¾½ ¾½ ¾½ Condos East Asbury Avenue Colorado Center Drive 25 ³ Legend ¾½ Proposed Bike/Pedestrian Path Alignment Mowed Vegetation qp Tree 0 80 160 Feet Environmental Engineering Resources, Inc. SITE PLAN Colorado Center Bicycle/Pedestrian Bridge Denver, Colorado Site Location: NE 1/4, NW 1/4, Section 30, Township 4S, Range 67W, 6th Principal Meridian Filename: Projects\10973501 Colorado Center Bike Ped Bridge\Biological Resources\Fig 2.mxd Job No. 1/09-735-01.8808 Drawn By: MJS Reviewed By: JNA Figure 2 Revision 1/21/2011
C10 Colorado Station Perpsective Colorado Center Bicycle/Pedestrian Bridge over I-25
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1. Facing South Along Cherry Street 2. Condominiums on the East Side of Cherry Street PINYON Environmental Engineering Resources, Inc. Colorado Center Bicycle / Pedestrian Bridge January 18, 2011
3. Southwest Corner of Jewell Avenue and Cherry Street 4. Facing South Towards Proposed Cherry Street Ramp PINYON Environmental Engineering Resources, Inc. Colorado Center Bicycle / Pedestrian Bridge January 18, 2011
5. Facing West Towards Proposed I-25 Bridge/Colorado Center 6. Facing East Towards I-25 Bridge PINYON Environmental Engineering Resources, Inc. Colorado Center Bicycle / Pedestrian Bridge January 18, 2011
7. Vegetated Area West of I-25 8. West End of Project Area at Birch Street PINYON Environmental Engineering Resources, Inc. Colorado Center Bicycle / Pedestrian Bridge January 18, 2011