USD Opens Alvarado Blvd. to Motorists
April 15, 2016 - Restoration of a sinkhole area on Alvarado Boulevard was completed by Union Sanitary District and the roadway opened to traffic yesterday. Final activities such as painting curbs may require one westbound lane to close today near New Haven Street, but the lane will re-open by 3 p.m. Crews are scheduled to return for completion of final lane and crosswalk striping on Thursday, April 21, weather permitting.
The sinkhole appeared the afternoon of October 14, 2015, and quickly grew, causing extensive damage to a 33-inch diameter sewer pipe that runs 20 feet below Alvarado Boulevard in Union City. A manhole in the area was also damaged when the sinkhole occurred, as were other utilities.
USD’s repair work was hampered by difficult soil and groundwater conditions. The District had to stabilize the site by pumping a large amount of groundwater out of the area before an assessment could be performed and the best repair option chosen. This required drilling three wells, each about 30 feet deep and two feet in diameter, through which the groundwater was pumped. Groundwater remained a challenge throughout the repair activities.
The project required closing westbound traffic lanes on Alvarado Boulevard between Fair Ranch Road and Fredi Street. Although USD searched for the cause of the sinkhole as repairs progressed, it is still unknown. Multiple factors could have contributed to the sinkhole. In addition to extensive groundwater, the affected area included sandy soils and infrastructure for several utilities.
The sewer line was repaired and a new manhole installed, with flows returning to normal in mid-March. Repairs to other utilities in the vicinity of the sinkhole were also completed.
“This work has been our number one priority, and we are happy to return Alvarado Boulevard to vehicle traffic”, said USD General Manager Paul Eldredge. “We appreciate the public’s patience during our efforts to protect the safety of motorists and others in the area while performing difficult and complex work. The District also thanks the City of Union City, New Haven Unified School District and the Alameda County fire department for their support of our efforts to minimize inconvenience to the public and ensure that appropriate access was maintained at all times for emergency services.”