Denver Water plans to reduce the Fraser River to 2 cubic feet per second starting Tuesday, with Vasquez Creek and St. Louis Creek also set for 2 cfs and Ranch Creek for 1.5 cfs. The cuts are expected to last until May 15 unless drought conditions improve or operational needs prompt a change, Sky-Hi News reported. Denver Water says the reductions are needed as drought leaves its reservoirs well below normal.
The utility reported that its reservoirs were 67% full on Oct. 5, compared with a typical 90% for that date, in its water-supply update. Separately, Drought.gov lists both August and January through August as Colorado’s driest on record since 1895, statewide context for the current shortage rather than a measure of conditions in the Fraser basin.
The planned level is below a reported flow rule that Sky-Hi News says has been in place since 1969 and requires the Fraser to maintain at least 4 cfs when Denver Water diverts. The available reporting does not explain how the 2-cfs plan is reconciled with that rule. A separate provision in the 2013 Colorado River Cooperative Agreement is not itself a minimum-flow requirement: beginning in the year the Moffat Project becomes operational, Denver Water must make 1,000 acre-feet annually from its Fraser Collection System available to Grand County for environmental purposes and incidental recreation, according to the agreement.
The low flows matter to communities that rely on the waterways. Winter Park Ski Resort’s sole water supply is the Fraser River, while Vasquez Creek is the town of Winter Park’s sole supply, Sky-Hi News reported. Local water districts have raised concerns that very low flows could complicate community water needs and wastewater requirements; shallow ice over low flows could also harm fish eggs and the small organisms that fish depend on, The Colorado Sun reported. These are risks raised by local stakeholders, not evidence that supplies or ecosystems have already been damaged.
There is a past low-flow comparison, but it is not a record of a recurring pattern: Denver Water told 9NEWS that the Fraser dropped to 1 cfs in 2002. That was a separate episode; the current plan calls for 2 cfs, 9NEWS reported.
Denver Water diverts water through the Moffat and Roberts tunnels to its Front Range system, which serves about 1.5 million people across eight counties. The Colorado Sun reported that the utility takes an estimated 60% of the Fraser’s native flow, while Front Range diversions generally take about 70% to 80%. The utility has also set a customer water-use reduction goal of 20% from its five-year average; by roughly the midpoint of the lawn-watering season, customers had cut use by about 2%, The Colorado Sun reported in July. How those conservation efforts and the planned diversions will affect reservoir levels and river conditions through the winter remains uncertain.
