1. Big French Creek Slide Timeline of Events
January 16, 2016: A series of rock slides occur during heavy rains. An emergency project is initiated to clean debris from roadway, monitor the slope, and provide traffic control through the end of the rainy season.
February 24, 2016: After continued rock slides, a supplemental emergency project is approved to install cable anchored rock fall drapery over the slide area as weather permits.
July, 11, 2016: After multiple attempts to collect the required geotechnical information are delayed due to continued falling debris, the needed drilling data is gathered and analyzed, and a solution is proposed. A “catchment” area at the bottom of the slope is to be excavated and a large wall constructed between the catchment area and the highway to catch debris. It is determined that the rock fall drapery would not be adequate and should no longer be pursued. A new emergency project is developed to design and construct this solution.
August, 2016: After obtaining necessary project clearances to excavate catchment area and construct debris wall, work begins. Work is halted in early October due to early rains triggering additional rock slides. On December 9, 2016, during a heavy storm, a large slide closes the highway.
Current Status: Caltrans has received approval to construct a temporary detour near the Trinity River. This detour is currently under construction, and is anticipated to be open to one way traffic by the week of January 15, Concurrent with construction of the detour, the slide area has been accessed from above, and work commenced from the top to the bottom to remove approximately 200,000 cubic yards of material, provide a more stable slope, finalize construction of the catchment area and debris wall, and eventually reopen Highway 299 to normal traffic. A follow up project will likely be necessary to construct drainage settling basins, provide maintenance access, and perform other work to finalize the slide repair.
All these plans and schedules are dependent on weather conditions. If site conditions change dramatically, the plan for the slide removal will adapt to the changing conditions.
At 9:00 am on Friday, January 6, the contractor was forced to stop operations because of heavy rain. Work will resume when weather and site conditions allow.
After the round of storms passed, work continued to clean up after heavy rains. Mud and debris hauled away and work to finish detour progresses.
The morning of January 17, an arrangement to pass the school bus and associated school staff became operational. The first passing went well.

2. Big French Creek Slide Tri-299-PM 23.3 Active Slide Area
Constructing temporary alignment, approximately 10’ higher than existing, one way traffic, expected to be open week of January 15th, 2016
Helena
Del Loma
Big Bar
Junction City
Weaverville
Douglas City

3. Big French Creek Slide Tri-299 PM 23.3 Access Route to Top of Slope
Cracks
Big French Creek Slide
Tri-299 PM 23.3

4. Detour progress as of 1-5-17, looking west.

5. Material from top of slide covering face of the slide, providing a protective covering.

6. View showing work at the top of slide
Before the storms came, the contractor was able to remove approximately 50’ from the top of the slide.
Rainy conditions have forced the contractor to stop operations at 9:00 am on Friday, January 6. Work will resume when conditions allow.

7. Face of slide after heavy rains, protective cover has been compromised.

8. Another view after heavy rains showing exposed rocks.