Alto Tunnel Study. Weekly Progress Report February 10, 2017

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1 Alto Tunnel Study Weekly Progress Report February 10, 2017 Report 1/Rev. No. 1 February 13, 2017

2 Table of Contents 1.0 Project Activities Underhill Site Drilling Progress Underhill Site Controls Project Support Activities Project Schedule Project Drilling Progress Updated Project Schedule Project Delays and Comments Project Items Summary Additional Project Items... 7 List of Photos Photo 1. Drill rig staged over the tunnel alignment survey Photo 2. Initial start of drilling through soil Photo 3. Cuttings removed with compressed air while drilling through rock at a depth of 40 feet Photo 4. Hammer attachment used to penetrate the rock material Photo 5. Traffic controls impended along Underhill Road Photo 6. Traffic control cones around vehicles on Underhill Road Photo 7. Erosion control implemented along the site perimeter of Underhill Road Photo 8. Erosion control implemented along the site perimeter Appendices Appendix A County of Marin Drilling Permit Appendix B Mill Valley Encroachment Permit McMillen Jacobs Associates 1 Rev. No. 1

3 1.0 Project Activities Site activities began at the Underhill Road project site on February 1, Initial project site work by Drill Tech Drilling and Shoring, Inc included grading, implementing erosion control measures, and mobilizing drilling and support equipment. Small bushes were removed and minimal grading was completed within the anticipated drill rig footprint and borehole locations. Drilling commenced on February 6, 2017 at the Underhill site at Borehole 2 location. Storm events the past week caused project delays and are outlined in Section 2.3 Project Delays. Figure 1. Drill rig and borehole locations above Alto Tunnel at the Underhill Road project site. McMillen Jacobs Associates 2 Rev. No. 1

1.1 Underhill Site Drilling Progress Drill Tech used a string, level, and measuring tape to orientate the drill rig along the surveyed tunnel alignment at the Underhill Road location.

4 1.1 Underhill Site Drilling Progress Drill Tech used a string, level, and measuring tape to orientate the drill rig along the surveyed tunnel alignment at the Underhill Road location. A bench was excavated to support the drill head equipped with a drag bit for the initial soil drilling. By the end of the day, Monday February 6 th, Drill Tech advanced through the soil to a depth of 16 feet where sandstone material was encountered. The drill rig was retooled for a down-the-hole hammer attachment to penetrate the dense rock material. By the end of the week of February 10 th, Drill Tech advanced through the rock and installed casing to a depth of 100 feet. During drilling the cuttings produced tan and gray rock material where the tan was noted as relatively softer and alternated in thicknesses of the two materials. Material depths and transitions for being recorded manually onsite. Total Depth 100 feet (2/10/17) Figure 2. Underhill site drilling progress. McMillen Jacobs Associates 3 Rev. No. 1

5 1.2 Underhill Site Controls Traffic control measures implemented along Underhill Road were adequate at cautioning and managing the low traffic volume and providing safe work zone. Graded site soil was suitably piled onsite and covered with plastic held with sandbags. Drill Tech utilized plastic sheeting as secondary containment for the air compressor stored onsite. Plywood was used to protect the ground surface at the entrance of the site on Underhill Road. Site erosion controls were implemented in anticipation of the heavy rain forecast. Drill Tech utilized silt fences, sand bags, and straw waddles to control the turbidity and allow settling of the site water. Filter socks were employed at the site perimeter curb locations for secondary sediment removal before entering a filter sock installed within curb storm drain on Underhill Road. No turbid water or oil sheen was observed entering the storm drain and the implemented erosion control measures adequately reduced the site runoff and control sediment transport offsite. Compressed air was used to clear the borehole of drill cuttings. Fugitive dust resulting from the drill cuttings was properly mitigated using water added to the compressed air. 1.3 Project Support Activities A permit application with the County of Marin Environmental Health for drilling and installing monitoring wells at the Underhill and Chapman locations was approved and applicable fees paid. The final drilling permit is attached in Appendix A for reference. David McMullen (County of Marin Environmental Health Services), arrived onsite on Friday, February 10, 2017 for a site walk and to observe the drilling methodology used onsite for the monitoring well installation. While onsite we addressed concerns of casing sealants, well monument construction, and the permitting process. Before leaving the site, David requested that the department be present during the construction of the first well monument. An EPA complaint was received by the Marin County Stormwater Pollution Prevention Program (MCSPPP). The onsite erosion control measures and Best management Practices were reviewed by MJA staff and documented. The Certified Unified Program Agency (CUPA) and MCSPPP Staff reviewed the provided project documentation and determined no further action was required from the department. The final Mill Valley Encroachment permit is attached in Appendix B for reference. McMillen Jacobs Associates 4 Rev. No. 1

6 2.0 Project Schedule 2.1 Project Drilling Progress The planned drilling activity at the Underhill site location was started at Borehole 2 and casing advanced to a total drilled depth of 100 feet. No boreholes have been completed at the Chapman site. See Figure 3 for the project drilling progress. Depth Below the Ground Surface (ft) ft 100 ft 0 ft 0 ft 0 ft Depth Below the Ground Surface (ft) 450 Underhill Borehole 1 Underhill Borehole 2 Chapman Borehole 3 Chapman Borehole 4 Chapman Borehole 5 Final Borehole Depth 123 ft 360 ft 415 ft 236 ft 333 ft Total Depth (2/10/17) 0 ft 100 ft 0 ft 0 ft 0 ft Previous Week 0 ft 0 ft 0 ft 0 ft 0 ft 450 Figure 3. Project drilling progress. McMillen Jacobs Associates 5 Rev. No. 1

2.2 Updated Project Schedule See Figure 4 for the updated Project 3-week look ahead schedule for the week starting February 13, 2017.

7 2.2 Updated Project Schedule See Figure 4 for the updated Project 3-week look ahead schedule for the week starting February 13, A complete schedule can be found on the Walk-Bike-Marin Projects and Programs website. Figure 4. Project Schedule as of 2/13/ Project Delays and Comments Due to a storm event of heavy rains the past week site work was limited at Underhill due to concerns of stormwater runoff and site disturbance. There was no drilling, and only site maintenance was performed on the following days: Tuesday, February 7, 2017 Wednesday, February 8, 2017 Thursday, February 9, 2017 The project delays related to the recent storm the schedule have impacted the project schedule. The delays have no impact on the current project budget scope items and have not incurred additional out of scope items. We suggest proceeding with the current construction of Borehole 2 and adjust the schedule after the completion of Borehole 2 planned for this week. McMillen Jacobs Associates 6 Rev. No. 1

8 3.0 Project Items Summary The items for this project include two boreholes at the Underhill site and three boreholes at the Chapman site. Individual hole depth estimates and percent complete are provided in Table 2. The five boreholes are included in Task 3.2 totaling 1565 feet in length. Table 1. Completed project items Task 3.2. Item No. Description Unit Completed Quantity Total Estimated Completed Underhill Site 1 Borehole 1 LF % 2 Borehole 2 LF % Chapman Site 3 Borehole 3 LF % 4 Borehole 4 LF % 5 Borehole 5 LF % Total LF % 3.1 Additional Project Items During this period the County of Marin Environmental Health Department was provided a monitoring well permit application and fee. Total costs associated with the permitting are outlined below. Table 2. Additional project items. Item No. A Payee County of Marin Environmental Health Department Description Total Quantity Monitoring well permit $1,001 McMillen Jacobs Associates 7 Rev. No. 1

9 Photos McMillen Jacobs Associates 8 Rev. No. 1

10 Photo 1. Drill rig staged over the tunnel alignment survey. Photo 2. Initial start of drilling through soil. McMillen Jacobs Associates 9 Rev. No. 1

11 Photo 3. Cuttings removed with compressed air while drilling through rock at a depth of 40 feet. Photo 4. Hammer attachment used to penetrate the rock material. McMillen Jacobs Associates 10 Rev. No. 1

12 Photo 5. Traffic controls impended along Underhill Road. Photo 6. Traffic control cones around vehicles on Underhill Road. McMillen Jacobs Associates 11 Rev. No. 1

13 Photo 7. Erosion control implemented along the site perimeter of Underhill Road. Photo 8. Erosion control implemented along the site perimeter. McMillen Jacobs Associates 12 Rev. No. 1

14 Appendix A County of Marin Drilling Permit McMillen Jacobs Associates

15 COMMUNITY DEVELOPMENT AGENCY ENVIRONMENTAL HEALTH SERVICES MARIN COUNTY CIVIC CENTER 3501 CIVIC CENTER DRIVE, ROOM 236, SAN RAFAEL, CA (415) FAX: (415) PERMIT TO INSTALL MONITORING WELLS Date of Issuance: February 10, 2017 Permit No.: MW B11836 (5) Date of Expiration: February 9, 2018 Street Address: 35 Underhill Rd, Corte Madera Ave, To: County of Marin DPW 3501 Civic Center Dr. San Rafael, CA Chapman Dr City: Corte Madera Assessor s Parcel No: To Driller: Drill Tech, Wymore Way, Antioch, CA Permission is hereby granted to construct five (5) monitoring well(s) at the above, indicated site. In order to provide the necessary inspections, the well driller shall notify this office at (415) at least two business days in advance of drilling the well. Also, contact Environmental Health on the day of the work to confirm. The annular seal shall not be placed until approval from Environmental Health Service is granted. CONDITIONS: 1. If the well is drilled on property owned by a party other than the applicant, this permit is not valid until applicable local encroachment permits or permissions are first obtained. Please contact the appropriate landowner, city, county, park or special district agencies to obtain permissions. 2. The Marin County CUPA (Office of Waste Management, Department of Public Works) or the local L.P.A. shall be notified whenever test results from sampling demonstrate chemical contamination or leakage of underground storage tanks. 3. Install sanitary seals with a minimum depth of five feet, or in this case, the depth necessary to seal the well s monument. Well construction shall meet the requirements of the current State of California Well Standards Bulletin (as revised) and the CCR Title 26. The well driller shall submit a Department of Water Resources Form 188 (Water Well Drillers Report) within 30 days of project completion. Issued by, David McMullen David McMullen, R.E.H.S OFFICE USE ONLY

16 Appendix B Mill Valley Encroachment Permit McMillen Jacobs Associates

APPROVED FOR ISSUANCE REFER TO ENCROACHMENT AND/OR CONSTRUCTION PERMIT AND PLAN COVER SHEET FOR SPECIAL CONDITIONS AND PERMIT NUMBERING

APPROVED FOR ISSUANCE REFER TO ENCROACHMENT AND/OR CONSTRUCTION PERMIT AND PLAN COVER FOR SPECIAL CONDITIONS AND PERMIT NUMBERING GENERAL NOTES: HOUSE GREEN HOUSE 1900 S. NORFOLK ST. SUITE 350 GARAGE GRADING