The St. Vrain Left Hand Conservancy District, whose mission is to protect water rights and improve management practices in the river basin, is in the first phase of developing a stream management plan for the 300,000-acre watershed. Its goal is to align strategies for maintaining the reliable delivery of water to agricultural users while also satisfying ecological and recreational goals, some of which could require higher flows in the main stretches of streams that feed the St. Vrain, such as Left Hand Creek, as well as the St. Vrain itself, which is a key South Platte River tributary.
“Whether you’re a domestic or agricultural water user, you have an opportunity to really be part of a strategic, balanced approach to meeting competing demands,” said Sean Cronin, the district’s executive director.
But Colorado water law is focused on the use of the state’s most valuable resource, and not on conservation, notes a September survey prepared by a firm hired by the conservancy district for the stream management plan.
“This causes water owners to shy away from change of use, dam modifications or other river improvements, fearing legal or financial challenges and a burden on their time — and farmers do not have time to give away,” the survey states, adding it also will be a challenge to have rights owners “‘open up’ about their decrees or the way they manage, use or store water, and there are sometimes long histories of relationships between agencies or people in how they work together with their water. Overcoming some of these social and political legacies, or positively using these relationships, will be a challenge to the process.”
Seeking balance at what cost?
Diverting water from stream beds through ditch delivery networks has long quenched otherwise dry agricultural lands on the Front Range, but the expansion of the practice over time has led to impacts some are now interested in mitigating.
Boosting the ability for fish and recreational users such as kayakers to pass diversions by altering or replacing infrastructural barriers has consistently been expressed as a priority.
So have improved ability to control timing and quantity of both ditch and stream bed flows, enhancing flood resiliency in the watershed and preventing impacts from municipal development.
“For the most part, this basin wants to work toward finding that balance,” Cronin said. “I won’t say we’re all in agreement of what the balance is, where that pivotal point is to make the balance, and I don’t think we’ll ever get there and that’s fine, as long as folks want to continue sitting at the table.”
While some Longmont-area ditch companies have already designed and implemented more passable diversions or are in talks with local officials about doing so in the near future, a move toward automating the opening and closing of ditch gates that are now moved manually to accommodate water share holders’ calls for supply also could emerge as a consideration for those relying on the watershed.
Being able to remotely open and close gates could help prevent flow heading into ditches when it isn’t needed, possibly allowing higher flows in main stream beds through areas where such water levels could benefit recreation and environmental health.
But doing so could come at a major cost. Terry Plummer, vice president of maintenance and operations for Left Hand Ditch Co., said the company, for reasons unrelated to stream management, next week will install an automated ditch gate that can be operated remotely in one location on its network at a cost of about $30,000.
If an effort to automate water delivery equipment were applied across the broader watershed, though, it would be needed in dozens of locations, and could require the construction of entirely new diversion structures in some areas, which can run cost hundreds of thousands for just one spot, Plummer said.
“We have no intentions of automating at this point in time,” Plummer said. “It’s just too expensive. The assessments (charged to share holders for ditch maintenance) are so high now because of the 2013 flood (damage) that we would have to raise assessments dramatically, and the farming can’t support that.”
He said grant funding would have to become available, with the right terms, to pursue widespread automation.
A method that helped maintain higher wintertime flows in the St. Vrain is likely no longer an option — for about 20 years until 2013, Longmont released water from its Ralph Price Reservoir storage at a rate of 3 cubic feet per second to maintain a winter flow of 5 cfs along the entirety of the river, according to city Water Resources Manager Ken Huson.
But state officials nixed that practice after changing how they account for water.
“It’s not something Longmont can just do on its own anymore like we used to,” Huson said.
Flow not only way to go
Other opportunities for bettering stream management in the St. Vrain watershed might not address flow, however, and still offer environmental and social benefits.
“What we’re going to come up with are management activities,” Cronin said. “Those could address flow, but it could be that an opportunity area doesn’t necessarily have a flow challenge, but a riparian floodplain connectivity challenge.”
Allowing streams to more easily access the floodplain by preventing their banks from becoming overly incised or congested can help avoid rushing waters during flood events via letting the excess flow spread out over flatland, instead of accumulating in steep, deep channels.
Removing the invasive crack willow tree, which has problematically proliferated across dozens of states, from local stream banks could help achieve that, and has already been worked on in some areas of the St. Vrain basin by the Left Hand Watershed Oversight Group.
“That’s really the issue with the current conditions and why there are disconnected floodplains, because we’ve had this encroachment of this invasive tree that has created a super stable bank, and has allowed incision to happen,” said Jessie Olson, the oversight group’s executive director. “We’ve got a number of places like that throughout the watershed that could use some additional connectivity basically by removing the invasive tree and laying back slopes.”