Plan to expand Chatfield Reservoir draws mixed reactions

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By Vicky Gits

The plan to expand Chatfield Reservoir in South Jefferson County is regarded by some as the best environmental alternative, but others see the projected loss of habitat, flooding of 600 acres and impacts on recreation as too great a price to pay.

The proposed changes will have a significant effect on wildlife, as well as on the recreational amenities that are part of the surrounding Chatfield State Park.

Under the proposal released June 8 by the U.S. Army Corps of Engineers, 587 acres of the 5,400-acre park would be flooded under peak conditions, spoiling wildlife habitat, downing trees and requiring the reconstruction of most park facilities, including the marina, boat ramp, swim beach and balloon launch area. Losses include 43 acres of cottonwood habitat and 211 acres of other tree cover.

In exchange, 20,600 acre-feet of storage capacity could be added to the existing 27,000 acre-feet, providing an additional renewable water resource to south metro water users and farmers. The capacity is achieved by reallocating a part of the basin that is currently dedicated to flood control.

The projected $184 million cost is to be covered by a group of 15 water users including Centennial, Castle Rock, Roxborough Water Supply District, Castle Pines Metro District and Castle Pines North Metro District. The proponents intend to acquire 888 acres elsewhere to make up for lost wildlife habitat.


More water, more mud

The reservoir height will increase by 12 feet from the current maximum level of 5,432 feet, which will expose a large amount of shoreline in the years when there is less water to fill the reservoir, said Scott Roush, park manager.

Because most of the water involved has a low priority (junior rights), the reservoir is likely to be full only about three years out of 10, Roush said.

"You are talking hundreds of feet from the swim facilities to the water, compared to now when it's just 40 feet," he said.

"Another big impact is the whole marina. There is an issue how will it operate if there are big fluctuations. You can only adjust a dock so much. They aren't designed to take that. There's a way to do it, but there's a cost. The water users will pay for it," Roush said. "It's going to cost more for weed mitigation, adjusting buoys. If it comes up to the tree zone, you have debris coming into the lake.

"A lot of that is going to be mitigated, but it's a matter of following through to make sure that everything is done to the standard and we still have an area that offers the same opportunity. That's what they say, but it's hard to visualize some of that. What if the money dries up and you are halfway through?"

‘A major aesthetic impact’

“I think it's a puff piece for the preferred alternative," said Polly Reetz, referring to the executive summary of the draft report and environmental impact statement.

"They don't talk about the impacts or the mitigation. I did not think they laid out what this is going to look like. They just say there are going to be some water fluctuations and impacts on vegetation. It eliminates 587 acres of park for public use that will be under water," said Reetz, the conservation chairman for the Audubon Society of Greater Denver.

"We all thought originally the impacts would be pretty benign, but they turned out to be substantial and some are not that benign. Mitigation may be difficult if not impossible," she said.

Reetz is concerned about the ability to replace the cottonwood forest and the free-flowing stream segments that would be affected.

The Audubon Society is asking for more than 60 days to submit comments.

The bathtub-ring effect

Ann Bonnell, second vice president of the Audubon Society of Greater Denver, lives a mile north of the reservoir.

"The lake is one of my very favorite places,” Bonnell said. “I've tried to protect the park from a number of things, including a glider port and a water slide.”

She complained about the potential creation of an unsightly "bathtub ring" around the perimeter.

"You have to deal with sanitation; electrical and all those things have to be redone. It's very complicated for the small yield you are going to get out of it.

"They are going to move (picnic pavilions) closer to C-470 and Wadsworth. Aesthetically, it's not as neat because you are going to hear the highway noise," Bonnell said. "They have really not explored all the alternatives."


Thirsty cities pay the price

Rick McLoud, water resources manager for the Centennial Water and Sanitation District, acknowledged that damage would be done, but insisted every effort would be made to lessen the impact.

The benefit of the project is that it develops new surface water as opposed to mining limited amounts of groundwater or water buried in underground aquifers, McLoud said. The Centennial Water District serves 90,000 residents in Highlands Ranch.

"They need reliable, renewable supplies you get from surface water. The groundwater here is not renewable. It's disconnected from the surface water system. … People are trying to lessen dependence on the nonrenewable component," he said. "That's what's driving this."

Since the storage capacity is on the river, it's more efficient, McLoud said.

McLoud agrees the water level is going to fluctuate more than in the past. But there is much that can be done.

"It will be different than it's been in the past. The goal is to have it not be something less or worse. There will be tree-planting, weed control and trails will be created. There's a lot that can be done to address the issues," he said, referring to $70 million allocated for environmental and $40 million for recreation mitigation.


Not an old-style project

"It's not impact-free. It will have real impact on the wetlands. At the same time, we think those are the lesser of evils," said Rob Harris, staff attorney with Western Resource Advocates.

"We were concerned eventually there would be a reason to build a Flaming Gorge pipeline or a large, structural, old-style water project to help meet the need in south metro," Harris said. "It isn't a direct endorsement, but we think Chatfield is one of our acceptable-plan projects.

"Our colleagues think it can be done right," Harris said. "There is a fairly nice wetland where the river meets the reservoir. The cottonwood stands there may not survive having the water-level rise. Basically, the bathtub ring would take over the good habitat."

Harris said a lot of effort is going into finding acreage off site to replace habitat that is flooded inside the park.

"We recognize this project has impacts, but in light of the millions of people expected to move to Colorado in 50 years, we are faced with difficult choices. This is a reasonable, nonstructural alternative to building a big water project," Harris said.

Becky Long, water caucus coordinator with the Colorado Environmental Coalition, takes a similar approach as Harris.

"Historically we have said no to reservoir projects,” she said. “But we think storage plays a role. … Chatfield is one where we think it might make sense. We recognize the impacts and mitigating them.

“I'm not sure I can say yea or nay today. How we mitigate the impacts is really important. It may take some creativity," Long said.

Contact Vicky Gits at vicky@evergreenco.com or 303-933-2233, ext. 22.

To voice your view …

The Army Corps of Engineers has scheduled public involvement meetings in connection with its June 8 release of the Chatfield Reservoir expansion project draft report and environmental impact statement.

• Monday, June 25, from 5:30 to 8:30 p.m. at The Wildlife Experience, 10035 S. Peoria St. in Parker.

• Tuesday June 26, at Dakota Ridge High School, 13399 W. Coal Mine Ave. in Littleton.

Hard copies of the report are available at the Columbine Library, 7706 W. Bowles Ave., and the U.S. Army Corps of Engineers, Tri-Lakes Project Office, 9307 S. Wadsworth Blvd.

Comments can be mailed to U.S. Army Corps of Engineers, Omaha District; CENWO-PM-AA; ATTN: Chatfield Reservoir Storage Reallocation FR/EIS; 1616 Capitol Ave.; Omaha, NE 68102-4901. Comments can also be e-mailed to chatfieldstudy@usace.army.mil. Comments must be postmarked or received no later than Aug. 7.


The entire study (544 pages plus appendices) is at this link:


Summary information about the study can be seen at www.chatfieldstudy.org.