From The Denver Post (Scott Willoughby):
Philosophically, the proposed water storage expansion of Chatfield Reservoir makes some sense. In reality, it makes some headaches.
Participants of the Chatfield Reservoir Reallocation Project took their turn before the Colorado Parks and Wildlife Commission in Lamar on Friday, formally presenting the “Fish, Wildlife and Recreation Mitigation Plan” essential for approval of the proposal to double the water storage in the south Denver reservoir. The presentation started the 60-day review clock for commission approval required by state statute and offered a closer look at the likely impacts to one of Colorado’s most popular state parks.
“No water project is without environmental impacts and the statute doesn’t require that the impacts be eliminated, it requires that we mitigate them,” said Mike King, executive director of Colorado’s Department of Natural Resources. “(The participants and stakeholders) are to be commended for being creative in getting us to this point. I’m hopeful that we can get this across the finish line in the next couple of months.”
The hurdles to be overcome at Chatfield range far beyond the environmental, however. The 1,423-acre reservoir and surrounding topography serve as a cornerstone of the state park system, annually attracting more than 1.5 million visitors and generating some $2.2 million in revenue. Impacts to the park during and after inundation of 587 additional acres are expected to be significant.
Wide fluctuations in water levels are anticipated as additional municipal and agricultural water storage join the reservoir’s current primary uses of flood control and recreation. An additional 12 vertical feet of potential water fluctuations is likely to have considerable impact on park operations and will require the relocation of multiple facilities when the reservoir fills to its new level.
The law does not require that a mitigation plan for recreation impacts be approved by the commission, however project participants have proposed plans to alleviate unavoidable impacts to recreation facilities and amenities.
“Areas that were recognized as being potentially impacted included the park, fish and wildlife, recreation and financial,” said Randy Knutson, board member of the Central Colorado Water Conservancy District. “Mitigation plans for all these impacts either have been developed or are in the development phases.”
“We feel that we’ve gone above and beyond the state law requirement,” added Randy Ray, water resources manager for the Centennial Water & Sanitation District. “This plan addresses all the concerns.”
While the 11 project participants have pledged up to $116 million to finance the potential impacts identified in studies by the U.S. Army Corps of Engineers and Colorado Parks and Wildlife, concerns remain. Foremost among them is the reservoir’s dramatically fluctuating water level.
Under the state park’s current operating agreement with Denver Water, Chatfield typically fluctuates no more than five feet between Memorial Day and Labor Day, offering recreational users reliable water levels for boating, fishing and other summer activities. The “Fish, Wildlife and Recreation Mitigation Plan” notes that the new “fluctuation zone” could be up to 21 feet, citing a comparison study of six other Front Range reservoirs showing that impacts (mud, weeds, mosquitoes, etc.) would be negligible.
Project participants insist that the reallocation proposal will have a positive impact on the South Platte River downstream from Chatfield, including an improved fishery as water is conveyed to downstream users from mid to late summer and through fall and winter. The “new reservoir” effect of added nutrients also has potential to improve fishing within Chatfield in the short term, although fluctuating water levels have been associated with elevated mercury levels in walleye at other reservoirs.
Reallocation participants have agreed to maintain water levels in the reservoir during critical walleye and smallmouth bass spawn periods. They also announced a new plan to preserve a gravel pond popular among recreational users that was initially subject to inundation.
“It’s an ongoing process. I feel better about some of the changes that they’ve made but we’ve got 60 days still to work through some of the details,” said Ken Kehmeier, a CPW aquatic biologist working on the project. “Bottom line is that it won’t be the Chatfield that everybody knows right now.”