Gross Reservoir will remain closed for weeks following engineer’s death


BOULDER COUNTY, Colo. — Gross Reservoir will stay closed for recreation for several weeks after a civil engineer died while working on Denver Water’s Gross Reservoir Expansion Project.

The employee, who was identified Tuesday as Matthew Liu, 28, died on Saturday. He had been driving a dump truck carrying about 7,000 pounds of rock when the road gave way near the Gross Reservoir Dam. The truck rolled down an embankment before sliding underwater.

Colorado State Patrol determined the truck, which fell in the water shortly after midnight, was about 43 feet under the water. During the daylight hours, rescue divers recovered Liu’s body.

Liu had six years of experience in construction. At the time of his death, he worked for Kiewit Barnard, which Denver Water hired for planning and pre-construction work at the Gross Reservoir.

The reservoir and recreation area has remained closed since then. This includes activities on the water, hiking and picnicking.

Denver Water announced Wednesday morning that recreation around the reservoir will stay closed to the public for several weeks. Crews still need to remove equipment in the reservoir — a process that will start with surveying the area to ensure the extraction resources are capable of reaching and removing the underwater equipment.

“This incident will have a lasting impact on all of us. We extend our thoughts to friends and family of the engineer who tragically lost his life and recognize that it’s going to be a long road for many, especially our extended family at Kiewit Barnard,” said Jim Lochhead, CEO and manager at Denver Water. “We now ask for the public’s patience as our contractor works to safely remove the vehicle from the reservoir and so that all involved parties can thoroughly investigate and make any changes necessary to ensure another accident like this does not occur again.”

More about the Gross Reservoir Expansion Project in Boulder County

The $464 million Gross Reservoir Expansion Project is expected to triple the size of the reservoir by raising the height of the existing Gross Reservoir dam by 131 feet. This will also expand the capacity of the reservoir by 77,000 acre-feet, or about 25 billion gallons.

For years ahead of this project, Boulder County leaders have strongly opposed it. However, in early November, county commissioners acknowledged the chances of winning a lawsuit to stop the project were slim. They agreed to the settlement at a public meeting on Nov. 2.

As part of the settlement, Denver Water will provide more than $12.5 million to help mitigate the impacts of construction, which was a $2.5 million increase beyond what the utility company had previously said it would provide. In addition, Denver Water said it would transfer 70 acres of land to the county to be added to the Walker Ranch open space. In exchange, Boulder County cannot dispute Denver Water’s claim that the project is exempt from review, the commissioners said.

According to Boulder County, the settlement addresses these four major points:

  • Reducing impacts to residents: Denver Water initially proposed providing $2.5 million towards residents that will be most impacted by the project. However, after hearing from the community, the commissioners asked Denver Water to double this mitigation pool to $5 million. Denver Water also is required to reduce noise and dust from the project by using electric power rather than diesel generators and to limit the hours of truck traffic and road work.
  • Reducing impacts to county roads: Denver Water will be required to meet the county’s Multimodal Transportation Standards related to intersection and road work and to leave Gross Dam Road in a better condition than before the project. Denver Water’s drivers need to complete bike awareness training and there will be some “truck free” days that benefit cyclists.
  • Reducing impacts to county recreation areas: Denver Water will provide $5.1 million for open space funding to replace lands that will be inundated by the increased reservoir capacity and transfer 70 acres of land near Walker Ranch open space to Boulder County.
  • Addressing impacts to the environment: Denver Water will provide $1.5 million to address the greenhouse gas emissions from the project and another $1 million for an important restoration project on the South St. Vrain Creek at the Hall Ranch Lyons Quarry to restore critical species habitat.

This settlement came after Denver Water filed a federal lawsuit in July 2021 alleging that Boulder County officials were stalling on a local permit that was needed so the utility could begin the long-planned reservoir expansion. Following this filing, Boulder County announced that the Gross Reservoir Expansion proposal was on hold. In an Aug. 10, 2021 motion, Boulder County asked the federal court to dismiss Denver Water’s lawsuit, stating the utility company “lost a state court case seeking to stop county review of the project.” A federal judge was prepared to hear arguments if a settlement wasn’t reached in November, according to The Denver Post.

In 2019, Denver7 went 360 on the many opinions around the expansion, specifically how Boulder County residents are upset about the expansion.

Denver Water outlines the project on its website here.