Denver: 2100 acre-feet for South Platte environmental flows

The South Platte River typically all but vanishes as it passes through Denver’s industrial neighborhood north of downtown, downstream of the Burlington Ditch diversion, near the Cherokee power plant. Photo/Allen Best
The South Platte River typically all but vanishes as it passes through Denver’s industrial neighborhood north of downtown, downstream of the Burlington Ditch diversion, near the Cherokee power plant. Photo/Allen Best

From The Denver Post (Bruce Finley):

The Denver Water and Colorado Parks and Wildlife officials said they’ve obtained 2,100 acre-feet of water that they will use strictly for environmental purposes…

“We’re trying to make the South Platte the best it can be for this city. … It’s not going to be like a Danube,” Denver Water manager Jim Lochhead said. “We can make it what it is, which is a plains river that creates an appreciation of the connection to water in this city. The city would not exist without that water supply.”

The idea is that putting more water into the Platte at the southwestern edge of metro Denver will mimic long-lost natural flows, to the extent possible given the channelization of the Platte after the 1965 flood that destroyed buildings in the floodplain. More water also would help a fish hatchery where state wildlife workers breed rainbow trout.

For more than two decades, Denver conservationists have worked at reviving the Platte corridor, building cycling-oriented pathways and riverside parks. It’s been complicated because metro Denver grew up around the river and, for more than a century, people exploited it as a sewer with industrial plants and discharge pipes draining into the water. Now as kayakers, surfers, skaters, waders and others flock to the river, city leaders face rising demands for more water, cleaner water and wildlife.
But just beyond Denver, farmers await every drop of the treated wastewater metro users put back in the Platte, water used to grow food. There’s so much demand for South Platte water across booming northeastern Colorado that parts of the river run dry.

By 2018, project leaders say, new environmental flows from Chatfield will keep that from happening — and create curves and pools favoring aquatic bugs and fish.

“Now we’ve got some water so that we can start to build the river back to being a natural-looking river. It is limited. The river won’t have access to the true floodplain. But we can build smaller floodplain ditches so that the river will look more like a sinuous river coming through Denver,” CPW senior aquatic biologist Ken Kehmeier said.

“The water will be used mostly during the low-flow times of the year,” the 65 or so days when water rights holders have the ability to dry up sections of the river, Kehmeier said.

“It will mean water stays in the river downstream of Chatfield, including the hatchery. That’s where the trout will come from. And brown trout in the river now, with this extra water, will be able to reproduce naturally.”

Lining up storage for the water proved crucial. Denver Water has committed to work with the Greenway Foundation to buy space for 500 acre-feet in an enlarged Chatfield Reservoir. This water adds to 1,600 acre-feet of water to be used only for environmental purposes that federal engineers required as “mitigation” for Colorado’s repurposing of the reservoir from flood control to water supply. The 500 acre-feet would be owned by the Central Colorado Water Conservancy District, a downstream agricultural entity, which agreed to pay annual operational and maintenance costs.

Storing water in Chatfield costs $7,500 an acre-foot, Denver Water officials said. They’ll spend $2 million to buy storage space, on the condition the Greenway Foundation does the same…

This push to put more clean water in the Platte through Denver coincides with broader environmental efforts. Federal, state and city engineers have been mulling possibilities for restoring other metro waterways, for which the U.S. Army Corps of Engineers has dangled possible funding.

Supporting Creative Use of a Dam to Meet Future Water Needs – and Save Plum Creek

This picture is an example of a head cut on another stream (Image courtesy of the <a href="https://www.env.nm.gov/swqb/Wildfire/Viveash/index.html">New Mexico Environment Dept.</a>) and Western Resource Advocates.
This picture is an example of a head cut on another stream (Image courtesy of the New Mexico Environment Dept.) and Western Resource Advocates.

From Western Resource Advocates (Robert Harris):

Better management and use of existing dams is a key tool to minimize new expensive, energy-consuming, and environmentally damaging large scale new dams or diversions from the West’s rivers.

We are a conservation group with a priority goal of saving rivers in the West. So you would think we would be opposing anything to do with dams. But the reality is that we believe that better management and use of existing dams is a key tool to minimize new expensive, energy-consuming, and environmentally damaging large scale new dams or diversions from the West’s rivers. Which brings us to today’s story about supporting more creative management of Chatfield Reservoir and saving Plum Creek.

The U.S. Army Corps of Engineers recently approved storing more water in Chatfield Reservoir on the South Platte River southwest of Denver to help meet Colorado’s existing and growing water needs. Western Resource Advocates, Conservation Colorado, and the Rocky Mountain Chapter of the Sierra Club support this decision because it follows the Smart Principles of water supply management by making more efficient use of existing reservoirs and local water supplies. In our view, select new-supply projects—including holding more water in the existing Chatfield Reservoir—high rates of water conservation, accelerated water recycling and reuse, and voluntary sharing of water with agriculture for other uses all can combine to meet and exceed 2050 water demands for the South Platte Basin. “Chatfield Reallocation” exemplifies the opportunities available to state water planners to meet reasonable anticipated water needs without building more costly, politically charged, large-scale concrete and steel water project proposals that cause major harm to rivers.

However, putting more water in Chatfield Reservoir will still harm wildlife habitat provided by nearby wetlands and cottonwood stands. These habitat areas are accustomed to a lower, and less variable, water table in the reservoir. As part of the agreement to re-allocate water storage space in Chatfield reservoir, the environmental impacts must be offset, or “mitigated,” through replacement and permanent protection of other wetlands and other important wildlife habitat. To this end, the project’s beneficiaries have deposited approximately $130 million into a special bank account dedicated to environmental and recreational mitigation. Western Resource Advocates is joined by representatives of relevant state and federal agencies and other stakeholders as a member on the Technical Advisory Committee for the Chatfield Reservoir Reallocation Project, which guides implementation of the environmental protection and restoration mitigation projects.

At its first meeting in late April, the Committee urged the mitigation company to use some of the mitigation funds to address rapidly deteriorating wildlife habitat along Plum Creek, which is above the reservoir in the park. Urban development in the Plum Creek watershed has significantly increased rain runoff flows that are scouring a deep channel into the creek bottom, and in turn, lowering the water table and draining high-quality wetlands next to the creek. This erosion, called a “head cut,” is unrelated to the Chatfield water storage project.

This year, the head cut in Plum Creek is advancing dozens of feet upstream with each rain storm. Western Resource Advocates and the Committee unanimously urged the mitigation company to stabilize the creek and stop the head cut. This will help restore Plum Creek’s health and provide good creek-side habitat for birds and other wildlife.

Mitigation projects like this one on Plum Creek demonstrate the potential of creative water supply solutions, including Chatfield Reallocation, to meet communities’ water needs and to fix significant local and regional environmental challenges. It also illustrates how dynamic mitigation projects can be since few anticipated that this habitat would, on its own, deteriorate so badly in such a short period of time. Without mobilizing the mitigation funding made possible by this project, Plum Creek’s wetlands might be lost for generations. Stay tuned to the Chatfield Reallocation Project as the stakeholders develop and implement this and other exciting protections for wetlands and rivers.

Rob Harris is a Western Resource Advocates attorney representing WRA, Conservation Colorado, and the Rocky Mountain Chapter of the Sierra Club on the Technical Advisory Committee for the Chatfield Reservoir Reallocation Project.

Proposed reallocation pool -- Graphic/USACE
Proposed reallocation pool — Graphic/USACE

Chatfield Reservoir: Lawsuit Claims “Massive Environmental Damage” From Project — Westword

Proposed reallocation pool -- Graphic/USACE
Proposed reallocation pool — Graphic/USACE

From Westword (Alan Prendergast):

As we reported back in 2012, the long-simmering proposal has set off alarm bells among environmentalists, bird fanciers and many park users because it involves flooding more than 500 acres of the 5,378-acre park and raising the water level by twelve feet. Critics say that will wipe out groves of cottonwood trees, destroy bird habitat, wetlands and walleye spawning areas, and leave an unsightly “bathtub ring” of barren mud flats around the reservoir when water levels are low. The lawsuit claims that the Corps improperly evaluated the project’s impacts and dismissed a number of less damaging alternatives to the current plan.

Chatfield draws 1.6 million visitors a year and hosts 375 different species of birds — fourteen of which are listed as protected by state or federal authorities. Audubon’s attorneys contend that the project will cost the state around $3.4 million in lost park revenues, much of which is used to support less popular parks.

But the most intriguing claim in the suit has to do with whether the project will actually be of much use in boosting water storage for various agricultural and suburban interests. Several of the parties who initially signed on to the project, including the Parker Water and Sanitation District and the City of Brighton, have since dropped out and sought to meet water needs from other sources. Others, including the City of Aurora, “are trying to leave the project or have already left,” the complaint states.

The reason for all those defections? While the project claims an estimated 8,539 acre‐feet of water per year as its average yield, the estimated “dependable yield” is zero. While the project has been presented as a “restoration” of the South Platte, the Corps’ own studies predict that the river’s flows would actually decrease nine months out of twelve after the project’s completion and increase only one month of the year. Much of the water storage is allocated to junior rights holders and may be available only three years out of ten.

“It’s a bad deal for the public and for Colorado,” said Polly Reetz, conservation chairman of Denver Audubon, in an statement announcing the lawsuit.

But the Colorado Department of Natural Resources and the Colorado Water Conservation Board remain solid supporters of the project, and backers insist that the overall effect on Chatfield will be minimal. Denver Audubon and other environmental groups have said they would prefer to see more conservation measures and less drastic storage projects.

More Chatfield Reservoir coverage here.

Chatfield Reservoir water supply project OK’d by feds, faces lawsuit — The Denver Post

Proposed reallocation pool -- Graphic/USACE
Proposed reallocation pool — Graphic/USACE

From The Denver Post (Bruce Finley):

Federal water engineers on Thursday launched the long-planned and controversial Chatfield Reservoir water supply project, closing a deal with Colorado sponsors.

Audubon Society opponents filed a lawsuit in federal court trying to block construction.

A reallocation of the South Platte River water that is captured in the reservoir, created in 1975 for flood control, is expected to add 2.8 billion gallons a year to water supplies.

But the project will inundate 10 percent of the premier state park.

Col. Joel Cross, the U.S. Army Corps of Engineers Omaha district commander, signed an agreement with the Colorado Department of Natural Resources and the Colorado Water Conservation Board — clearing the way for state-supervised construction after 15 years of negotiation.

“This completes the study and gives approval to move forward. This is a huge milestone,” Army Corps of Engineers project manager Gwyn Jarrett said.

Colorado natural resources director Mike King on Oct. 6 signed for the state. Colorado water supply planners have estimated that, by 2050, the state’s population probably will grow to between 8.6 million and 10.3 million people, up from 5 million in 2010. Today’s water supplies are expected to fall short by 390,000 to 450,000 acre-feet.

“As we look to meet our state’s future water needs, taking advantage of existing infrastructure and maximizing yield from Chatfield is by far the most environmentally responsible option available,” King said.

“This project will not pull any additional water from the West Slope, and the environmental impacts can and will be mitigated through an aggressive plan to ensure that Chatfield remains a tremendous recreational and wildlife viewing site,” he said. “At the same time, the new project will provide additional water to the already stressed farms and communities along the South Platte.”

The 20,600 acre-feet of water stored in Chatfield Reservoir, located 25 miles southwest of downtown Denver, has been reallocated for municipal and industrial water supply along with other purposes, including agriculture, environmental restoration, recreation and improving fish habitat.

Federal engineers said using Chatfield to augment water supplies is better than building a new dam and reservoir elsewhere.

The plans say the water level will rise by up to 12 feet and the project will provide an average of 8,539 acre-feet of water (about 2.8 billion gallons) for municipal, industrial, environmental and agricultural use.

This will inundate 10 percent of the 5,378-acre Chatfield State Park, which draws 1.6 million visitors a year.

Lengthy reviews and negotiation among federal engineers, state officials and water users led to plans to mitigate adverse impacts.

The plans describe new habitat for birds and replacement of park structures and roadways. State officials said water providers purchasing storage space in the reservoir must place funds to pay for mitigation work in an escrow account before construction begins. And no new water can be stored until on-site recreational and environmental work is done.

The Army’s assistant secretary for civil works, Jo-Ellen Darcy, has deemed the Chatfield project “technically sound, environmentally acceptable and economically justified.”

Bird-watchers opposed it. Cottonwoods that serve as bird habitat likely will be lost.

The Audubon Society of Greater Denver this week filed the lawsuit in U.S. District Court, arguing that federal authorities arbitrarily dismissed better alternatives and that the Clean Water Act allows only the least-damaging alternative. It argues that federal documents show the “dependable yield” of water from the project is zero and that project reviewers’ “segmentation” in evaluating impacts led to an improper analysis.

“They need to take another look at alternatives they dismissed,” Audubon Society member Gene Reetz said. “Everybody realizes that demands for water are growing. And, especially with climate change, water is going to be very short. We all have to get more serious about conservation.”

More Chatfield Reservoir coverage here.

New storage project aims to ease demand for West Slope water — Grand Junction Daily Sentinel #COWaterPlan #ColoradoRiver

Proposed reallocation pool -- Graphic/USACE
Proposed reallocation pool — Graphic/USACE

From The Grand Junction Daily Sentinel (Dennis Webb):

The state of Colorado has signed an agreement to boost Front Range water storage, one of the things a growing chorus of Western Slope voices has been calling for to ease the demand for more transmountain diversions. Gov. John Hickenlooper on Friday announced the agreement between the state and the U.S. Army Corps of Engineers to provide for greater water storage at Chatfield Reservoir in Chatfield State Park. The action will result in an increase of up to 75 percent in storage for uses other than flood control.

It comes after Club 20’s board last month weighed in on an ongoing state water planning process by calling for measures including prioritizing “the storage of Front Range water on the Front Range.” That’s a position that also was endorsed earlier as part of a position paper on the state water plan that was signed by numerous headwaters counties, towns, water utilities and other entities. That paper specifically mentioned Chatfield as an example of such a project that could be undertaken.

The storage project announcement comes amid increasing Western Slope concern that the new state water plan will result in yet more transmountain diversion projects being pursued. In August, Associated Governments of Northwest Colorado sent Hickenlooper and Colorado Water Conservation Board director James Eklund a letter urging them to oppose any more diversions of water across the Continental Divide.

“The Western Slope in Colorado has no more water to give,” said the letter, signed by AGNC Chair Mike Samson, a Garfield County commissioner, and Vice Chair Jeff Eskelson, a Rio Blanco County commissioner.

It also was signed by former Western Slope state lawmakers Ron Teck and Jack Taylor, several local office holders in the region including Mesa County Commissioner John Justman, and ranching, energy and other business interests.

The AGNC refers to a letter from several Front Range water interests this spring calling for assurance that a new water project involving Colorado River water will be part of the state plan for meeting future needs.

“This would be too much of the same old story,” says the AGNC letter, which argues that for too long the thirst of the Front Range has been quenched “at the sacrifice of Western Slope communities.” It notes that western Colorado already provides more than 400,000 acre-feet of water a year to the Front Range.

Club 20 didn’t specifically oppose more diversions, but said the state plan should contain provisions including prioritizing municipal conservation, “including a statewide conservation goal and measurable outcome, and a higher goal for water providers that are using water supplies of statewide concern such as permanent dry-up of agricultural land and/or need a new transmountain diversion from the Colorado River basin.”

The idea of more Front Range storage of water originating there has received additional attention after last September’s Front Range flooding caused some to lament about water running downstream that might have been stored instead.

The Chatfield project has been in the planning and permitting stages for more than a decade, Hickenlooper’s office said in a news release.

“The Chatfield Reservoir Storage Reallocation Project will help farmers irrigate crops and assist communities working to replace limited groundwater with sustainable surface supplies. The project also has the benefit of storing more Front Range water and easing demand for water from the Western Slope. Importantly, as well, the project increases the capacity of an existing reservoir, reducing the impacts to the environment that could be associated with an entirely new reservoir site,” the news release said.

The state water plan principles endorsed by the headwaters jurisdictions don’t include outright opposition to more transmountain diversions, but lay out numerous conditions for more diversions occurring, including that existing diversion water first be “re-used to extinction to the extent allowed by law.”

More Chatfield Reservoir coverage here.

Gov. Hickenlooper announces agreement for greater Front Range water storage

Here’s the release from Governor Hickenlooper’s office:

Gov. John Hickenlooper announced today that the State of Colorado and the U.S. Army Corps of Engineers have signed an agreement that will provide for greater water storage – up to a 75 percent increase for uses other than flood control – at Chatfield Reservoir, a project in the planning and permitting stages for well over a decade and one securing important new water supplies for the Front Range and northeast Colorado.
The Chatfield Reservoir Storage Reallocation Project will help farmers irrigate crops and assist communities working to replace limited groundwater with sustainable surface supplies. The project also has the benefit of storing more Front Range water and easing demand for water from the Western Slope. Importantly, as well, the project increases the capacity of an existing reservoir, reducing the impacts to the environment that could be associated with an entirely new reservoir site.

Possible impacts that may occur from the project, located within the popular Chatfield State Park, will be mitigated to highest standards required by the Army Corps and State of Colorado. Water providers purchasing new storage space in the reservoir are required to mitigate impacts and to place funds for such mitigation in escrow before construction begins. Additionally, no new water will be stored until key on-site recreational and environmental mitigation milestones are complete.

With the signing of the storage agreement, the early phases of mitigation work can begin. The State of Colorado now has the ability to contract with water providers who wish to purchase space in the reservoir. The project will support agricultural partners including the Central Colorado Water Conservancy District and municipal partners, such as the Centennial Water and Sanitation District and other members of the South Metro Water Supply Authority.

More Chatfield Reservoir coverage here and here.

Chatfield Reallocation Project: “This a premier state park, and it’s going to have the heart knocked right out of it” — Polly Reetz

Proposed reallocation pool -- Graphic/USACE
Proposed reallocation pool — Graphic/USACE

From The Denver Post (Joe Vaccarelli):

The Army Corps of Engineers has approved an expansion of Chatfield Reservoir that will also bring some infrastructure improvements to the park, but patrons shouldn’t expect to see work done any time soon. According to Army Corps of Engineers project manager Gwyn Jarrett, it could be three to four years before work is underway and two to three years after that before it’s complete.

The project was approved in late May and has been in discussion since the mid-1990s. The expansion will add 20,600 acre feet of water capacity — which could raise water levels in the reservoir by 12 feet — for joint use, flood control and water conservation. The $183 million project will help supply water providers in the metro area and across the Front Range as population and demand increases.

“This project will meet a portion of the expected demand in Colorado,” Jarrett said. “It’s not going to solve the problem, but it will help with the growing population.”

Once construction does start, most of the work will be done in the off-season, but people can expect that certain portions of the park could be closed at times. Part of the construction will include improving some of the amenities at the park such as new recreation buildings, picnic tables, beach areas and bathhouses.

“A lot of amenities date back to the mid-to-late 1970s when the project was constructed,” Jarrett said.

Chatfield State Park manager Scott Roush said the park doesn’t have to do much to get ready for the construction, but his staff will be involved with the design process when that kicks off, possibly this fall.

Part of that discussion will include the marina, which may have to move because of the rising water levels.

Public feedback had not been all positive, as some organizations feel that this project will damage some environmental aspects of the park.

The plan will flood more than 500 acres of the park and inundate some cottonwood trees near the reservoir, destroying habitat for several species of birds.

“We initially thought at first that (the project) was fairly benign, but we didn’t know that it will do massive environmental damage on one of the largest parks in the metro area,” said Polly Reetz, conservation chairperson for the Audubon Society of Greater Denver.

Reetz had other problems with the plan, saying that increasing the capacity of the reservoir doesn’t guarantee more water. She was also displeased that the state passed legislation to permit loans to water providers in order to pay for the project.

Roush said that while they will lose some trees, some would be relocated to other parts of the park.

“There’s been a lot of feedback about the cottonwood trees. We’re going to lose some trees; they will come back eventually,” he said.

But Reetz said there is no guarantee that the trees will come back and she was surprised the corps went with the proposal, saying it was the most harmful environmentally.

“It’s a really bad deal for the public,” Reetz said. “This a premier state park, and it’s going to have the heart knocked right out of it.”

More Chatfield Reservoir coverage here.