Rio Grande Roundtable recap

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From the Valley Courier (Ruth Heide):

Colorado Division of Water Resources Division III Division Engineer Craig Cotten told attendees at Tuesday’s Rio Grande Roundtable meeting that the dry appearance of the river, particularly in Alamosa, is a sign the state is current on its debt to downstream states so more water can be diverted to area irrigators without having to send it all down the river. “We are looking really good on the Rio Grande,” Cotten said. “We are meeting all of our obligation right now with return flows. That’s why the river is fairly dry through Alamosa, because we have got a little bit of water going to the West Side and Chicago Ditches and not a lot of water going through Alamosa.”

Cotten said 2010 turned out to be a less-than-average year with water flows on the Rio Grande. The annual forecast for the river is currently 540,000 acre feet. An average year would run 650,000 acre feet, “so we are a fair amount below average at this point in time,” Cotten said. The current forecast is even lower than the June 1 prediction of 575,000 acre feet on the Rio Grande, Cotten pointed out. Of the 540,000 acre feet flow on the Rio Grande for the year, 140,000 acre feet are obligated to New Mexico and Texas to meet Rio Grande Compact requirements. “We do have a fairly good obligation to downstream states, but we have already been able to deliver quite a bit of that water to the downstream states,” Cotten said. He said currently only about 5 percent of the state’s obligation on the Rio Grande is still owed, and that obligation is being met through return flows.

The Conejos River system is also meeting its obligation to downstream states, Cotten explained. That river system is also below average in total forecast flow, Cotten added. An average annual flow on the Conejos River system is 325,000 acre feet. This year’s adjusted forecast is 285,000 acre feet, which is down from the June 1 prediction of 315,000 acre feet. Of the total flow, the Conejos River system is obligated to send 99,000 acre feet downstream, “and currently we have delivered all the water we need to during the irrigation season,” Cotten said. During November and December the Conejos system will deliver more water downstream, and that will be sufficient to meet the Rio Grande Compact obligation, according to Cotten…

In addition to reporting on the status of the Rio Grande Compact and the Valley’s major rivers, Cotten reported to the Rio Grande Roundtable that groundwater rules are still under construction and the state engineer is hopeful they will be promulgated by the end of the year. Modeling work is currently being conducted for different areas of the San Luis Valley to determine how much impact wells have on rivers so adequate replacements for injurious depletions can be made. Cotten said that modeling work is nearly completed and he hoped it would be finished in the next month. With that completed, the advisory group that is working with the state engineer to develop groundwater regulations can finish up the sustainability portion of the regulations, Cotten explained…

Cotten also updated the group on the status of the first water management sub-district case. The sub-district of the Rio Grande Water Conservation District is designed to reduce irrigation in the closed basin area of the Valley to protect senior water rights, help meet Rio Grande Compact obligations and replenish Valley aquifers. The sub-district’s plan of management proceeded through the court, objections, trials and judicial ruling and is now pending a decision from the Colorado Supreme Court, which Cotten said might not occur until next spring.

More IBCC — basin roundtables coverage here.

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