Diablo Road Culvert Emergency Replacement

As of Sunday, April 16, Diablo Road is re-opened. Town staff and contractors worked through the weekend to complete the Diablo Road Culvert Replacement Project through to paving. Some additional tasks will be scheduled in the coming weeks, including a guard rail on the westbound side of the road and road striping.

Important Project Update

The Town is pleased with how quickly the Diablo Culvert Replacement Project is coming along, although a few circumstances beyond our control have led to extending the completion date. At this point, we expect to re-open Diablo Road on Tuesday, April 18.

Town engineering teams and contractor crews have been working diligently, and are near the finish line for this project. Unfortunately, both the wet weather and supply issues have hampered our progress. On Saturday alone, more than 1,000 tons of aggregate base (finely crushed rock) was delivered to the site – but not nearly as much as we had hoped – before the plant shut down. To mitigate supply issues as much as possible, crews have continued to work on other tasks within the project while we wait, to make sure that the delay is as short as possible.

These last days of the culvert project are filled with acquiring large quantities of supplies from multiple vendors, coordinating heavy equipment and precision engineering. This is a critical emergency replacement, and we appreciate the support the community has shown throughout. We will continue to provide updates on the project through Tuesday, and appreciate your patience while we make our roadways and drainage system better and safer.

It’s Day 5 of the Diablo Road Culvert Replacement project, and crews were busy over the weekend! In addition to continuing to build the replacement culvert pipe on-site, crews built a structure to pump water out of the project area, as well as divert water the culvert would normally handle. This is called a cofferdam, and will be especially helpful with this week’s anticipated rainfall, allowing the project to move forward as well as ensuring proper drainage. While we do expect rain this week, work is expected to continue and the cofferdam is expected to handle the rainfall successfully. For more information, view the project FAQ on this page.

Tomorrow is the big day! The Diablo Road Culvert Replacement project begins, along with the removal of several compromised eucalyptus trees. The culvert project is expected to end April 13, weather permitting, and the tree removal project may extend through the end of April.

Here are some tips to be prepared:

• Subscribe to updates: If you have not already, use the "Stay Informed" box on this page to subscribe to project updates.
• Review the detour map: We have developed a detour map that indicates closures and one-way traffic sections.
• Plan ahead for alternate routes: Leave a little early and have patience with your fellow drivers over the next three weeks.

While this project will present some obstacles in getting around Town, it will result in enhanced safety for our streets and drainage systems.

In continuing efforts to make the Diablo Culvert Emergency Repair Project most efficient, the Town has scheduled removal of compromised eucalyptus trees over the same project period. As many in the community reported, more than 20 trees along Diablo Road near Alameda Diablo are prone to falling after recent storms. The Town is working with the private landowner to remove the trees, which will be done during the culvert replacement project window, March 23-April 13, weather permitting. During this time, Diablo Road between Fairway Drive and Alameda Diablo will be set up for one-way traffic only.

The Town has developed a detour route map with this area identified, as well as suggested alternate routes for eastbound and westbound travel to avoid the project area. Click here to download a PDF of the map for reference.

Please note that the Diablo Community Services District – not affiliated with the Town - intends to close the intersection of Avenida Nueva at Diablo Road. That closure is noted on the detour map and questions can be directed to: generalmanager@diablocsd.org

As the Town continues to prepare for the culvert replacement project, we are using multiple outreach methods to make sure the community has as much advance notice as possible for this urgent project. The final elements of the communications and outreach plan is being put in place this week, including:

• Deployment of 17 electronic and static advance warning signage at 13 locations, to the east and west of the project site
• Coordination Contra Costa County District 2 Supervisor’s Office, Contra Costa Public Works, San Ramon Valley Fire Protection District, San Ramon Valley Unified School District, TRAFFIX School Bus Service, and the Athenian School
• Direct communication with the Diablo Community Services District representatives, Mt. Diablo State Park representatives, Diablo Country Club, and St. Timothy’s Church
• Direct mail notification to 3,600+ residents that take access to and from the Diablo and Blackhawk Road corridor
• News Flash through the Danville Area Chamber of Commerce and
• Press release and updates on all Town platforms, which have been viewed by more than 9,800 followers.

Once the project begins, Diablo Road will be CLOSED TO THROUGH TRAFFIC and travelers are asked to take an alternative route. A detour route map will be posted this week.

The Town is looking forward to completing this project as soon as possible to head off any further deterioration of the culvert.

Portion of Diablo Road will close for critical drainage infrastructure replacement.

The Town of Danville will replace a drainage culvert on Diablo Road, which will be closed to through traffic from Alameda Diablo to Avenida Nueva beginning March 23. The replacement project is necessary to maintain safe travel on Diablo Road and integrity of the Town drainage system, as the existing culvert pipe is at the end of its 60-year lifespan.

Town engineers inspected the culvert pipe while making storm-related repairs to the roadside slope in January. They found the pipe to be flattening, causing slope erosion and a dip on the surface of Diablo Road. The approximately 21-day project will include trenching across Diablo Road, removal of the outdated culvert, fabrication of the new culvert on-site, and installation of the replacement. The project is being planned with efficiency of time and resources, and full closure of Diablo Road will result in the shortest project duration and most efficient replacement of the critical drainage infrastructure.

Town staff have identified the potential project duration of March 23 to April 13 to make best use of nearby school break schedules. Diablo Road is expected to be closed for the duration of the project, from east of Alameda Diablo to Alameda Nueva.

The Danville Town Council appropriated funds for a construction contract for the emergency replacement of the Diablo Road Culvert. During the February 21 Town Council meeting, staff presented background and plans for the project, including a public outreach plan. The Council authorized the emergency storm drain culvert replacement under the local emergency declared January 10.

Read the full staff report here.