From The Pueblo Chieftain (Chris Woodka):
“What we’re trying to do is look at the reservoir operations before we’re at the point where we’re making decisions,” said Jim Broderick, executive director of the Southeastern Colorado Water Conservancy District, which administers the program. “We’re trying to manage it so it does not spill.” There is little danger that winter water would spill in most years. It is far down the ladder of priorities used by the Bureau of Reclamation to determine which accounts would be released as the reservoir fills. “If winter water were to spill, there would be so much water no one would know what to do with it,” Broderick said. Water stored in most excess capacity accounts would spill first. Right now, that totals more than 36,000 acre-feet and an average winter would result in a spill of about 14,000 acre-feet under current conditions if no changes are made…
A snag could come in late April because federal rules require a maximum level on April 15 for Lake Pueblo to accommodate flood waters. The court decree that set up the winter water program gives ditch companies until May 1 to move their winter water from the previous year out of storage. Meanwhile, Reclamation is clearing out space in Turquoise and Twin Lakes to make room for next year’s imports. At the same time, Lake Pueblo will fill even more as it stores river flows in the winter water program, which allows storage rather than the former practice of flooding fields in winter months. For years, the Southeastern District routinely approved requests to store carryover water more than one year. That’s not likely now, Broderick said…
Last year, about 140,000 acre-feet of water were stored in the winter water program, but only about 48,000 acre-feet in Lake Pueblo. Water also is stored in John Martin, Lake Meredith and other downstream reservoirs. There are still 15,000 acre-feet in Lake Pueblo, primarily in accounts for the Bessemer, Catlin and High Line canals, which cannot use downstream storage. “If you can help us get the water out by April 15, that will help us manage everyone’s water a little more easily,” said Roy Vaughan, Fryingpan-Arkansas Project director for Reclamation.
“We can get it out by April 15 if the weather is good and the ground is ready,” replied Dan Henrichs, superintendent of the High Line Canal. “But if it’s not and the wind blows, it’s gone.”
Update: Here’s a look at the model being developed to measure transit loss in the Arkansas River from Pueblo Dam to John Martin Reservoir, from Chris Woodka writing for The Pueblo Chieftain. From the article:
[Engineer Russ Livingston] is developing a transit loss model for the Arkansas River from Pueblo Dam to John Martin Reservoir.
The reach is the most complicated along the river because of tributaries, diversions and natural features. Water is lost as it splashes on the banks, soaks into the aquifer or becomes mired in riverbed ponds and evaporates. The rate of evaporation is also influenced by whether there is a lot of water in the river or just a little. The rate is factored in when a large block of water is released from Pueblo Dam to a headgate miles away or moved into John Martin. The trouble is, the current rate being used is 0.07 percent per mile, a figure based on a court case from the 1940s and applied since the 1970s…
More data is being included in the new study – $120,000 is being provided by the Colorado Water Conservation Board, Lower Arkansas Valley Water Conservancy District, Southeastern Water Conservancy District and other partners. Information from 58 gauges at four-hour intervals from several events in carefully chosen conditions are being used, Livingston said. The model can also be calibrated and verified against historic events. “We can segment out natural flows versus reservoir releases,” Livingston said. “At the end, you have a tool that can show you how well your model works.” The information can be useful both for ditch companies trying to account for their own water deliveries, as well as for the state in making sure other water rights aren’t injured.
More Arkansas Basin coverage here.