Gross Reservoir
Expansion Project


Gross Reservoir
Expansion Project


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Environmental Commitments

Provide $2 million towards aquatic habitat improvements on the Upper Colorado River.

Provide $1 million to the Upper Colorado River Wild and Scenic Management group to fund flow-related projects to protect the outstanding and remarkable values within segments of the Upper Colorado River.
Provide $6 million to Grand County to use towards environmental projects, and continue to participate in the “Learning By Doing” collaborative effort, which has already resulted in tangible positive environmental impacts on the West Slope.

Construct and maintain sediment pond on Berthoud Pass to keep the Fraser River bottom clean. Check out, “Good for drivers, bad for the Fraser River.”

Restore a portion of Fraser Flats in Grand County. Check out, “Keep it cool: Good for the Fraser River and its trout.”

Release water into Ranch Creek in response to high temperatures found through water temperature monitoring. Check out, “Searching for solutions to help trout keep their cool.”

Monitor stream temperatures and water quality in Gross Reservoir, South Boulder Creek and the Fraser River Basin.

Provide funding towards Colorado Parks and Wildlife’s cutthroat trout habitat projects to protect and restore native trout populations.

Through a cooperative process, replace culverts on Fraser River, Cabin Creek and St. Louis Creek with aquatic organism passage culverts that will enable free passage of fish and other aquatic organisms.

Provide flushing flows in the Williams Fork and Fraser River basins.

Provide more than 1,000 acre-feet of water in Grand County for environmental purposes.

Complete a stream restoration project on South Boulder Creek.

Create an environmental pool in Gross Reservoir that will be managed by the Cities of Boulder and Lafayette to provide flows into South Boulder Creek during periods of low or no flows.

Allow Grand County to store up to 2,500 acre-feet of water in Williams Fork Reservoir for environmental purposes.

Complete a stream restoration project on the Williams Fork River.

Begin stream bank monitoring on the North Fork of the South Platte River and South Boulder Creek to identify erosion and/or unstable banks, and make repairs, as needed.

Construct a fish ladder on Cabin Creek in Grand County.

Convey approximately 540 acres of land near the Moffat Tunnel to the U.S. Forest Service for permanent protection and management as part of the National Forest System.

Protect raptor species, fight invasive species, relocate rare plant species and responsibly remove trees and brush in the reservoir’s expanded footprint.

Continue to participate in the U.S. Fish and Wildlife Service’s Upper Colorado River Recovery Program and the Platte River Recovery Implementation Program, both designed to protect endangered species.

Online Office Hours

Now that construction has begun, we will continue to offer online one-on-one appointments with our project representatives who can answer your questions about the Gross Reservoir Expansion Project. We invite you to search for an available time and book an online meeting here.

We look forward to speaking with you!


First steps on Gross Reservoir expansion

Feb. 27, 2022 - TAP - After 20 years of preparation, first signs of construction work emerging in vicinity of dam. After nearly two decades of planning and permitting, Denver Water’s work to expand Gross Reservoir northwest of Denver is set to kick off. Over the...

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Learning By Doing 2022 Annual Report

Grand County Learning By Doing Cooperative Effort (LBD) has a goal to maintain, and where reasonably possible, restore or enhance the aquatic environment in the Fraser, Williams Fork, and Colorado River basins and their tributaries in Grand County, Colorado. See a...

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Breathtaking work nearly 300 feet underwater

August 23, 2021 - TAP - Major project replacing large debris grate at Gross Dam requires experts in the harrowing field of saturation diving. Raitt stresses the project is wholly unrelated to the planned expansion of Gross Reservoir. It would be happening regardless...

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All the ways we save (It’s not just shorter showers!)

August 6, 2021 - TAP There are a few things many customers might know about Denver Water’s efforts to use water efficiently. There was that fun and flashy and very effective 10-year “Use Only What You Need” campaign that cut per person water use by 22%. Denver Water...

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Fact or Fiction

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