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: Minimize Impacts to Vegetation. To the greatest extent possible, minimize impacts to vegetation while allowing the implementation of the Project. Vegetation to remain should be protected from construction activities by temporary fencing.  

•    AMM AES-2: Staging Areas. Staging areas should not be located where they require removal of vegetation unless deemed appropriate by the Caltrans Project biologist and the Caltrans Project landscape architect. 

•    AMM AES-3: Storage of Construction Materials. Construction materials and equipment should be stored in screened staging areas beyond direct view of the motoring public. 

•    AMM AES-4: Avoid Impacts to Existing Trees. Adjustments to the alignment of pathways and other features allowing damage to trees to be avoided or minimized should be explored. 

•    AMM AES-5: Certified Arborist during Construction. A Certified Arborist should be on-site during construction to determine whether impacts to trees can be avoided and whether realized impacts necessitate that a tree be removed.

 
•    AMM AES-6: Directional Lighting. Directional lighting and/or shielding for night work should be used. 

•    AMM AES-7: Architectural Treatment. The architectural treatment of proposed Project elements should be incorporated where appropriate. This may include coloring new concrete paving, stamping or otherwise adding decorative elements to proposed pedestrian structures, including railings, anti-graffiti coatings, and other elements as proposed during the Design phase of design by the Caltrans Office of Landscape Architecture.

•    AMM AES-8: Erosion Control. Apply erosion control seeding and similar measures to all areas of disturbance beyond pavement. 

•    AMM AES-9: Follow-up Planting Requirements. Following construction, highway planting should be implemented to fully rehabilitate the landscape of the Interchange. Extensive planting will be required, and a follow-up or “child” project is likely to be required. Because mature trees will be replaced with smaller trees, some of which may not survive to maturity, they should be replaced at a ratio greater than 1:1, potentially with some of specimen size, i.e., 15-gallon or larger boxed trees. 

•    AMM BIO-15: Rare Plant Pre-construction Survey and Rare Plant Salvage and Transplantation Plan. During the spring season prior to construction, Caltrans will conduct focused pre-construction surveys for the rare plants identified in the Project area. The extent and abundance of the rare plants will be mapped and flagged in the field for future relocation, salvage, and transplantation. These surveys will be conducted during the season in which the rare plants are detectable and in the phenological stage of development for correct identification (typically late spring). 

•    If a rare plant is identified within the Project area during the pre-construction survey, a rare plant transplantation plan will be prepared. The transplantation plan will be submitted to the regulatory agencies for approval prior to the beginning of construction.  
•    AMM BIO-16: California Ridgway’s Rail and California Black Rail Pre-Construction Surveys. For portions of the Project that are within 700 feet of Corte Madera Marsh (the eastern portion of the Project Footprint), if work will occur during the rail nesting season (February 1 through August 31), surveys will be conducted to determine whether the species are present. Protocol-level surveys, if required, will be conducted beginning between January 15 and February 1. A minimum of four surveys will be required. Each survey should be 2 to 3 weeks apart, and the final survey should be completed by March or mid-April to ensure that no California Ridgway’s rail or California black rail are present during construction. Surveys will be completed prior to the initiation of construction, with 3 weeks remaining after completion of surveys and before Project initiation to submit results to CDFW for review. Protocol survey requirements will adhere to the most recent USFWS/CDFW protocols. 

•    If California Ridgway’s rail and/or California black rail are detected during pre-construction surveys, then Project activities will not occur within 700 feet of an identified detection (or smaller distance if approved by USFWS and CDFW) during the rail nesting season. If rail activity is detected within the 700-foot buffer, immediate consultation with USFWS and CDFW is required. 

•    AMM BIO-17: Bat Monitoring Protocols. If a bat or bat colony is observed nesting or roosting in active construction areas at the Project area, construction activities that would imminently harm bats will stop within 150 feet of the roosting location until a qualified biologist develops a site-specific bat avoidance plan to implement at the roosting site. Once the plan is implemented, Project activities may recommence with Project biologist oversight at that location. 

•    AMM BIO-18: Preconstruction Surveys for CRLF. Preconstruction surveys for the CRLF will be conducted by the Project biologist within 14 calendar days of the initiation of project activities in suitable upland and aquatic habitat prior to ground-disturbing activities, vegetation removal, and Wildlife Exclusion Fencing (WEF) installation. Surveys will be conducted as outlined in the 2005 USFWS species survey guidelines for CRLF. Access to habitat during surveys may be limited by appropriate safety measures and protocols available at: 
https://www.fws.gov/media/revised-guidance-site-assessments-and-field-surveys-california-red-legged-frogamphibians. 

Preconstruction surveys will include:
o    Foot surveys will be conducted of potential frog habitat within the Work Area and accessible adjacent areas (within at least 50 feet of Work Area).

o    Potential cover sites (burrows, rocks, soil cracks, vegetation, and other potential refuge habitat) and any areas of disturbed soil for signs of CRLF will be investigated. 
Native vertebrates found in cover sites within the Work Area will be documented and, if handling is allowed, relocated to an adequate cover site in the vicinity. Species that cannot be relocated due to special protection status will be addressed in coordination with the appropriate agency(s) with jurisdiction.

•    AMM BIO-19: Wildlife Exclusion Fencing. Before starting construction, WEF will be installed where wildlife could enter the Project area. Locations of the WEF will be determined in coordination with the onsite biologist. WEF installation locations will be identified during the plans, specifications, and estimate phase of the Project; the final plans will depict the locations where WEF will be installed and how it will be assembled/constructed. The special provisions in the bid solicitation package will clearly describe acceptable WEF material and proper WEF installation and maintenance. The WEF will remain in place throughout the Project duration while construction activities are ongoing and will be regularly inspected for stranded animals and fully maintained. The WEF will be removed following completion of construction activities or when construction is completed at that location at the discretion of the Project biologist. 

•    AMM BIO-20: CRLF Monitoring. During construction in and near potential CRLF habitat, the following protocols will be observed by the Project biologist during construction monitoring:

o    Within 24 hours prior to initial ground-disturbing activities, portions of the Work Area where potential CRLF habitat has been identified will be surveyed by a Project biologist(s) to clear the site of frogs moving above ground or taking refuge in burrow openings or under materials that could provide cover.

o    A Project biologist(s) will be present during all initial ground-disturbing activities and vegetation removal in suitable refugia habitats for CRLF to monitor the removal of the top 12 inches of topsoil.

o    If potential aestivation burrows are discovered, the burrows will be flagged for avoidance.

o    After a rain event, and prior to construction activities resuming, a qualified biologist will inspect the Work Area and all equipment/materials for the presence of CRLF.

o    Upon discovery of a CRLF individual(s) in an active construction area, all work will cease within a 50-foot radius of the frog. The frog will be allowed to leave the site on its own; or if the frog(s) does not leave on its own, it will be relocated as close to the Project site as feasible and with permission from the property owner and placed in a natural burrow by a Project biologist with the appropriate USFWS 10(a)1(A) handling permit. The USFWS will be notified by phone and email within 1 working day of any CRLF discovery in the Project area.

•    AMM WQ-1: Water Quality Best Management Practices. This Project will require a 401 Permit from the San Francisco Bay RWQCB. It is anticipated that the RWQCB permit will require a SWPPP, which will provide guidance on erosion control BMPs to be implemented to minimize wind- or water-related erosion. These BMPs will also be implemented via language in the Construction Site Best Management Practices (BMPs) Manual (Caltrans 2017), which provides guidance for including provisions in all construction contracts to protect sensitive areas, and prevent and minimize stormwater and non-stormwater discharges. BMPs will include wind erosion controls (such as temporary covers, hydraulic mulch, hydroseeding and wood mulching), and drainage inlet protection. 

•    AMM WQ-2: Design Pollution Prevention Temporary Construction BMPs. The BMPs recommended for potential temporary construction impacts resulting from the project are: (1) job site management (2) sediment control (3) waste management and materials pollution control, (4) non-storm water management, (5) stockpile management, (6) tracking controls, (7) wind erosion controls, and (7) drainage inlet protection.  

•    AMM WQ-3: Design Pollution Prevention BMPs Post Construction: Design pollution prevention BMPs will be applied for post-construction erosion control since the Project involves DSA within Project limits. The BMPs will control post-construction impacts resulting from the Project. 

•    AMM WQ-4: Post-Construction Treatment BMPs. Because new impervious surface is more than 1-acre, post-construction stormwater treatment measures need to be provided for the new impervious surface. Furthermore, because net new impervious surface is more than 1 acre, hydromodification is required to control all the post-construction impacts resulting from the Project. 

•    AMM WQ-5: Full Trash Capture Devices. The Project area is located within a significant trash concentration area, therefore permanent trash capture devices will be considered during the design phase of the Project. 

•    AMM Noise-1: Specifications for Controlling Noise and Vibration. Noise from construction activities is not to exceed 86 A-weighted decibel 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. 

•    AMM Noise-2: Noise Levels During Construction. The following measures would be implemented during construction to reduce noise:

o    Restrict the times of overly loud construction activities to between 6:00 a.m. and 9:00 p.m. (except on holidays).

o    Equip all internal combustion engine-driven equipment with intake and exhaust mufflers that are in good condition and appropriate for the equipment.

o    Locate all stationary, noise-generating, construction equipment, such as air compressors, portable power generators, or self-powered lighting systems, as far as practical from noise-sensitive receptors.

o    Use quiet air compressors and other quiet equipment where such technology exists.

o    As practicable, have construction equipment conform to Section 14-8.02, Noise Control, of the latest Caltrans Specifications.

•    AMM TRANS-1: Traffic Management Plan: To minimize potential effects from construction activities to motorists, bicyclists, or pedestrians using local streets, a TMP will be developed by Caltrans and implemented throughout construction. The TMP will include public information, motorist information, incident management, construction, and alternate routes. The TMP will also include elements, such as detour and haul routes, one-way traffic control, flaggers, phasing, and use of CHP Construction Zone Enhanced Enforcement Program (COZEEP). During construction, the TMP will reduce impacts to local residents as much as feasible, enhance safety of travelers and maintain access to businesses in the local area. The TMP will also provide access for police and emergency service providers. Lane closures will be planned in coordination with Caltrans, Marin County, and the City of Corte Madera, and will include notices to emergency service providers, and the public in advance.