SON-121 Bridge Railing Upgrade
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Potential Less Than Significant Impacts Identified
The Draft IS/ND's analysis of project impacts identified potentially less than significant impacts which will be avoided by adhering to the following Avoidance and Minimization Measures (AMMs):
• AMM-AES-1, Vegetation Impacts and Protection: Minimize impacts to vegetation to the greatest extent possible while allowing the Project to be implemented. Vegetation to remain should be protected from construction activities by temporary fencing when vegetation is close to construction-related activities.
• AMM-AES-2, Staging Areas: Staging areas should not be located where they require the removal of vegetation or cause impacts to the roots of adjacent trees.
• AMM-AES-3, Concrete Color: Color treat concrete portions of bridge railings and anchor blocks to reduce visual change and maintain the consistency of the Project corridor. Consult the Caltrans Office of Landscape Architecture during the PS&E phase to coordinate the architectural treatments of Project components.
• AMM-AES-4 Revegetate Disturbed Areas: Revegetate disturbed areas with regionally native seed mix.
• AMM-BIO-1, Proper Use of Erosion Control Devices: To prevent CRLF from becoming entangled or trapped in erosion control devices, plastic monofilament netting (i.e., erosion control matting) or similar material would not be used within the Project footprints. Acceptable substitutes would include coconut coir matting or tackified hydroseeding compounds.
• AMM-BIO-2, Preconstruction Surveys for California Red-Legged Frog: Preconstruction surveys would be conducted by a USFWS-approved biological monitor. Visual surveys would be conducted immediately prior to the beginning of ground-disturbing activities. Suitable breeding and dispersal habitat within the Project footprints includes refugia habitat (such as in or under shrubs, downed logs, small woody debris, and burrows), which would be inspected. If an individual is observed, it would be evaluated and relocated in accordance with the observation and handling protocols outlined in AMM BIO-5. Fossorial mammal burrows would be inspected for signs of CRLF usage to the maximum extent practicable. If it is determined that a fossorial mammal burrow may be occupied by a CRLF, USFWS would be contacted and work would be stopped.
• AMM-BIO-3, Biological Monitoring: A USFWS-approved biological monitor would be present onsite during construction-related activities that have the potential to result in take of CRLF to monitor for CRLF. The USFWS-approved biological monitor may stop work if deemed necessary for any reason to protect CRLF and would advise the Resident Engineer (RE) or designee on how to proceed accordingly.
• AMM-BIO-4, Timing of Construction: Ground-disturbing activities would be restricted to the dry season (i.e., between June 15 and October 31), and when CRLF are anticipated to be estivating in moist refuges and not dispersing through the Project area.
Construction-related activities would not occur during rain events or within 24 hours following a rain event. Prior to resuming construction-related activities, a USFWS-approved biological monitor would inspect the construction area and construction vehicles, equipment, and materials stored onsite for the presence of CRLF. CRLF would be allowed to move away from the construction area of their own volition or would be moved by the USFWS-approved biological monitor.
• AMM-BIO-5, Discovery of a Special-Status Species: The biological monitor would have the authority to halt work through coordination with the RE in the event that a special-status species is discovered in an active construction area or might otherwise be at risk. The RE would ensure construction-related activities remain suspended in any construction area where the biological monitor has determined that the special-status species could be harmed. For CRLF, work may resume when the individual moves away from the construction area of its own volition or is moved out of harm’s way by a USFWS-approved biological monitor. For other federally and state listed species, USFWS and/or CDFW would be contacted on how to proceed before work is allowed to resume.
• AMM-BIO-6, Construction Materials Storage: For onsite storage of construction materials that could provide shelter for CRLF, an open top trailer would be used to elevate the construction materials above ground surface to reduce the potential for CRLF to climb into the construction materials.
• AMM-BIO-7, Worker Environmental Awareness Training: Construction personnel would attend a mandatory worker environmental awareness training (WEAT) delivered by a qualified biologist prior to beginning construction. WEAT would provide information on special-status species and the construction personnel’s responsibility in reducing, avoiding, or minimizing impacts to special-status species during construction. At a minimum, WEAT would include a description of special-status species and migratory birds that may occur in the Project area; a discussion of the potential occurrence of special-status species within the Project footprints; an explanation of the status of special-status species and protection measures under federal and state laws and regulations; and the description of avoidance or minimization measures to be implemented to conserve special-status species and their habitats as they relate to the Project. Information on special-status species would be provided to construction personnel, along with compliance reminders and relevant contact information. Documentation of WEAT and sign-in sheets would be kept on file and available on request.
• AMM-NOISE-1, Nighttime Construction: Construction noise levels are not to exceed 86 dBA Lmax at 50 feet from the Project site from 9:00 p.m. to 6:00 a.m. per 2018 Caltrans Standard Specifications, Section 14-8.02. Noise resulting from construction activities should be controlled and monitored.
• AMM-NOISE-2, Public Outreach: Public outreach would be required before Project construction and throughout the Project construction to update residents, businesses, and others about upcoming activities and Project time frames. Public outreach has the potential to entail sending notices to nearby residents, notifying the city and/or county, and posting a notice on the Project website.
• AMM-NOISE-3, Construction Noise Levels: The following measures would be implemented to reduce noise levels during construction where feasible:
o Equip an internal combustion engine with a manufacturer-recommended muffler that is in good condition. Do not operate an internal combustion engine within the Project footprint without the appropriate muffler.
o Do not idle construction equipment unnecessarily.
o Maximize the distance between stationary noise-generating construction equipment, such as air compressors and portable power generators, and noise-sensitive receptors.
o Ensure all construction equipment conforms to Section 14-8. 02, Noise Control, of the latest Caltrans Standard Specifications.
• AMM-TRANS-1, Transportation Management Plan: A TMP would be prepared prior to the beginning of construction to aid in coordinating and providing further safety measures for those accessing the Project corridor during construction. The TMP would identify traffic delays and alternative routes for emergency and medical vehicles associated with essential services, and would minimize impacts to service ratios, response times, and other performance objectives for public services. The TMP would provide priority to emergency vehicles during traffic control, as well as include instructions for response or evacuation in the event of an emergency.
Anticipated Permits
The Project is anticipated to receive a Biological Opinion from the U.S. Fish and Wildlife Service (USFWS) for California red-legged frog (Rana draytonii; CRLF). Approval of funding for the Project is required by the California Transportation Commission for each phase of the Project. No other permits, licenses, agreements, certifications, or approvals are anticipated to be required for the Project.