The Gross Reservoir Expansion Project will add 77,000 total acre feet — 72,000 for Denver Water use and 5,000 for an environmental pool that provides additional water for South Boulder Creek during low-flow periods — nearly tripling reservoir capacity.
Denver Water’s five-member Board of Water Commissioners on Wednesday approved a two-year, $4.5 million contract with Kiewit Barnard, a Joint Venture, for planning and pre-construction work during the final design phase of the $464 million Gross Reservoir Expansion Project.
If the team’s performance during the planning and pre-construction phase meets Denver Water’s expectations, a separate contract to build the dam may be signed between Denver Water and Kiewit Barnard.
“This is a major milestone in our 16-year effort to expand Gross Reservoir, as its original designers intended decades ago, to ensure a more reliable water supply in a future marked by greater uncertainty in weather patterns,” said Denver Water CEO/Manager Jim Lochhead.
Denver Water, the state’s largest water utility, serves 1.4 million people in Denver and surrounding suburbs.
Gross Dam enlargement concept graphic via Denver Water
The Gross Reservoir Expansion Project will raise the height of the existing dam, completed in 1954, by 131 feet, allowing the reservoir to nearly triple in size. When complete, the reservoir will be capable of holding about 119,000 acre-feet of water to provide greater system balance and resiliency.
The selection process for a construction manager/general contractor for the project began in August 2018 with information meetings, followed by a formal Request for Qualifications in October 2018. Three teams responded to the request and underwent extensive evaluations and interviews by a selection team that included experts from Denver Water, the project’s design engineer and subject matter experts.
The selection team focused on a value-based competitive process that examined each team’s qualifications, project approach, technical approach and cost.
“Kiewit Barnard met Denver Water’s high bar for doing a project that’s important not only to the 1.4 million people who rely on us for their drinking water, but also to the people who live around the reservoir,” said Jeff Martin, Denver Water’s program manager for the expansion project.
“We were impressed by the team’s experience with roller-compacted concrete dam construction, innovative approach and commitment to safe and responsible building practices,” Martin said.
The project calls for adding 900,000 cubic feet of concrete to the existing structure and building the first roller-compacted, concrete, arch dam in the United States. When complete, the Gross Dam will be the tallest in Colorado and the tallest roller-compacted concrete dam in the U.S.
“Kiewit Barnard, a Joint Venture, is very pleased to have been selected to work on this important project to support water demand for the greater Denver area,” said Jamie Wisenbaker, senior vice president of Kiewit Infrastructure Co., and an executive sponsor of the project. “We believe the team’s collective infrastructure experience in dam and reservoir construction and engineering will be a huge asset and look forward to safely delivering a high-quality project on time for Denver Water and the region.”
Kiewit is one of North America’s largest construction and engineering organizations with extensive heavy-civil experience in water/wastewater construction, including serving as lead contractor on the Oroville Spillways Emergency Recovery project in California. Kiewit is the No. 1 contractor for dams and reservoirs in the United States according to Engineering News-Record. The company also has strong roots and experience in Denver and across Colorado, including having constructed the Interstate 25 T-REX Expansion project, the U.S. 34 Big Thompson Canyon emergency repair project and the I-225 Light Rail Line project. The company also is building Denver Water’s new Northwater Treatment Plant.
Barnard Construction Co. Inc. brings a long track record of safety and quality on infrastructure projects in the U.S., including construction on more than 80 dams, reservoirs and dikes over the last four decades. The company’s work in this area includes new construction, raising dams and conducting emergency repairs. In 2019, Barnard was honored as a “Global Best Project” award winner by Engineering News-Record in the dam/environment category for the Muskrat Falls North and South Dams project located in Muskrat Falls, Newfoundland and Labrador, Canada.
The Gross Reservoir Expansion Project is awaiting a final federal government approval from the Federal Energy Regulatory Commission. Provided the remaining federal approvals come by the end of this year, the project is slated to be complete in 2025.
When finished, the expanded reservoir and associated mitigation projects will create what the Colorado Department of Public Health and Environment has described as a net environmental benefit to state water quality by generating a wide range of environmental improvements to streams, river flows and aquatic habitats.
Colorado’s boat inspectors have intercepted 51 mussel-infested boats this year, the same number as all of last year; and we’re only half-way through the boating season. Photo credit: Colorado Parks & Wildlife
Here’s the release from Colorado Parks & Wildlife (Joe Lewandowski):
The number of boats infected with mussels intercepted in Colorado by inspectors in 2019 is already even with the total from last year – and we’re only halfway through the boating season.
“I am just being completely over-run by mussel infested boats,” said Robert Walters, CPW’s assistant manager for the aquatic nuisance species program. “We are already up to 51 interceptions this year. We are having interceptions just about every day at waters throughout the state. And most of the boats are coming out of Lake Powell.”
Colorado Parks and Wildlife is warning boaters that they must clean, drain, dry and disinfect their boats before traveling to any reservoir in Colorado, especially when boats are brought in from out-of-state. Boats coming in from heavily infested Lake Powell are especially problematic. While boats are supposed to be inspected as they leave the desert impoundment, inspection stations there are overwhelmed and not all boats are thoroughly inspected. Mussels have even been found on paddleboards and canoes that have been in Lake Powel.
All boats that are not previously “sealed” at Colorado reservoirs receive a thorough inspection and engine flush at inspection stations. Any boats found with mussels must be completely decontaminated, a process that can last a week or more.
Colorado’s reservoirs are mussel free and the state and cooperating agencies operate a robust inspection program. But if an infestation occurs, it could be devastating for reservoirs and water-based recreation.
The number of boats infected with mussels is increasing. In 2018, 51 boats with adult mussels were found at inspection stations, far more than the previous record of 26 boats in one year. Since the ANS program started in Colorado in 2008, CPW staff and other entities have completed nearly 4.5 million boat inspections, more than 90,000 boats have been subject to decontamination procedures and more than 200 vessels with confirmed mussel infestations have been intercepted and decontaminated.
Mussel infestations cause a variety of major problems. Because mussels consume plankton, they disrupt the food web and out-compete sport fish and native fish. Mussels clog infrastructure, including reservoir dams, outlet structures and distribution systems that carry water for irrigation, municipal and industrial uses. Mussels also infest boats and damage engines.
Mussels have caused billions of dollars in damage, especially in the upper Midwest and Lower Colorado River. Nearby states where mussel infestations exist, include Utah, Arizona, Kansas, Nebraska, Texas and Oklahoma.
Kirstin Copeland, manager at Ridgway State Park, explained that the companies and organizations that own most of Colorado’s reservoirs could shut down all water-based recreation.
“They are concerned about potential damage to their infrastructure,” Copeland said. “They could say no to all boating.”
All boat owners who have been to Lake Powell should take extra care to inspect every inch of their craft and trailer – including lines, anchors, seat cushions, live wells and paddle craft. Owners can also call CPW if they have questions about the aquatic nuisance program and inspections.
The extreme water flow in the Arkansas River through Southern Colorado is finally dropping, It is now half of what it was a month ago. “We have come down to what we really refer to as the sweet spot,” said Echo Canyon Rafting, Owner, Andy Neinas, “So all sections of the Arkansas are open.”
Through the month of June there was arguably too much of a good thing. Water so high some potential customers staying away. Water was running over 5,000 Cubic Feet Per Second (CFS). Rafting companies agree to avoid certain sections of the river when the water is that high.
The flow dropped to 2,800 CFS this week. It means all sections of the river are now prime for rafting…
There is still a lot of snow on mountain peaks that feed water to the Arkansas River. Similar to the extended ski season this year, rafting will likely run longer than normal. Above average flows could continue into September.
We knew the June snowmelt would boost Colorado’s thirsty reservoirs, and now we can see just how much: Statewide, the reservoirs went from 59% capacity at the end of May to 76% at the end of June.
That still leaves plenty of room for more water, but the reservoirs are now sitting above average, at 105% of the normal capacity…
The Gunnison River, Upper Colorado River and Upper Rio Grande basins all saw significant upticks in reservoir levels. The Gunnison jumped from 60% to 85%; the Upper Colorado from 67% to 92%; and the Upper Rio Grande more than doubled, from 26% to 54%.
“It took a little while for the melt to happen (which was generally a good thing to mitigate any flooding concerns), but now that the melt has nearly completed, the streams and rivers are really flowing, and the reservoirs have started to fill nicely,” Russ Schumacher, a climatologist with the Colorado Climate Center in Fort Collins, wrote in an email…
The Dillon Reservoir is now at 97% capacity, up from 73%. The Blue Mesa Reservoir is now at 84%, up from 54%. Lake Granby is at 91%, up from 64%. The McPhee Reservoir, which was already at 88% capacity, is now full…
Further down the Colorado River, Lake Powell in southern Utah has seen its levels rise slightly, Schumacher said, but it’s still below average. The levels there should rise as the uptick in Colorado and Utah rivers travels south. But it could take one more wet year to see Lake Powell return to normal levels, Schumacher said.
The moisture in Colorado has had another benefit: The state is still 100% drought-free. And there’s been even more improvement in that area. The Palmer Drought Severity Index in Colorado , which sat at -0.72 in May, jumped into positive territory, at 2.28, indicating normal levels for the first time since the latter half of 2017.
Big water flows remain on the Arkansas River but the level has finally subsided enough for commercial raft trips to return to the Royal Gorge section of the river west of here…
The high water level advisory was lifted Wednesday after the water level went below 3,200 cubic feet per second for the first time since June 8. The advisories mean commercial rafters voluntarily avoid certain sections of the river because water levels are considered dangerous…
To put this year’s river levels into perspective, when the water level dipped to around 3,000 cubic feet per second Wednesday, it was well above the average level of 1,730 CFS for this time of year, according to the U.S. Geological Survey.
The river flow has varied wildly this time of year from a minimum flow of 254 CFS in 2002 to a maximum flow of 4,600 CFS in 1983.
