Gross Dam expansion is a good plan

Denver Water serves 1.4 million people in Denver and surrounding communities, and that figure will rise substantially in the coming decades. As more residents demand service, climate change increasingly will exert its own strain on the water supply. One of the primary ways the utility plans to meet this imminent challenge is by expanding one of its northern storage facilities, Gross Reservoir, in the foothills southwest of the city of Boulder.

The project has met with intractable opposition. It’s the subject of lawsuits and uncertain government reviews. Neighbors are scandalized by the prospect of years of disruptive construction, and some environmentalists contend the project won’t even be able to perform its intended purpose.

But a dispassionate consideration of the project leads to the conclusion that Denver Water’s plan to expand Gross Reservoir is a reasonable and responsible measure, provided the utility proceeds with the utmost sensitivity to the residents who would be impacted by construction and with the expectation that increased storage is no substitute for continued conservation efforts.

The roots of the project go back to the proposed Two Forks Dam. Denver Water had proposed storing water from the Colorado and Platte rivers by building a 615-foot dam southwest of Denver near Deckers. But a coalition of environmental groups successfully opposed the project, which the Environmental Protection Agency spiked in 1990. Environmentalists argued at the time that a better option would be for Denver Water to expand a storage facility it already operated: Gross Reservoir.

Now that the utility is following opponents’ former advice, environmentalists have changed their mind about Gross. The project would raise Gross Dam by 131 feet to 471 feet, roughly tripling the

reservoir’s current capacity. The reservoir pulls water from the headwaters of the Colorado River, and critics argue that the utility should refrain from further depleting that waterway, which runs all the way to the Gulf of California and is subject to the Colorado River Compact, an agreement that governs water allocation in seven states that rely on the river as an invaluable resource.

Construction to expand Gross Reservoir would indeed bring acute hardship to nearby residents, and concern for local environmental damage should not be dismissed (it would require the removal of about 650,000 trees). But construction is temporary, and the environmental impact seems less intolerable than merely regrettable when weighed against the project’s purpose of ensuring for decades the delivery of a vital resource.

Utilities should be judicious in exercising their rights to Colorado River Basin water, but the volume associated with the proposed Gross expansion is relatively small. As part of planning for the expansion, Denver Water worked with Western Slope communities in the Colorado River Basin to earn support for the project, efforts that in 2012 resulted in the Colorado River Cooperative Agreement, which calls for Denver Water to help restore habitats and maintain flows in the Fraser River, a Colorado River tributary in Grand County. Some Western Slope officials so favor implementation of the CRCA that a Grand County commissioner in March warned of “a ton of litigation” were Boulder to block the Gross expansion.

Boulder County officials have a legitimate interest in reviewing what would be the largest construction project in county history, and they are encouraged to take an exhaustive look at Denver Water’s plans. Any objections to the expansion of Gross Reservoir, however, should be based on factors intrinsic to the proposal, not on a mere preference for Gross to be left alone.