From The Pueblo Chieftain (Chris Woodka):
Farmers are still not happy with the state’s accounting of the impact of surface irrigation improvements on return flows to the Arkansas River.
“We’ve got to change the formula,” Lamar farmer Dale Mauch told officials Friday after learning of preliminary results from a two-year pond study at a meeting hosted by the Prowers County Soil Conservation District. “We’re getting screwed here. Does Kansas owe me water?”
The pond study is being conducted under a state grant through the Lower Arkansas Valley Water Conservancy District and won’t be finished until next year. But results from 2013 show that ponds leak about twice as much as assumed under a state formula adopted in 2010 surface irrigation rules.
The rules are meant to assure that Colorado does not take more of its share than it is entitled to under the Arkansas River Compact with Kansas, said Assistant Division Engineer Bill Tyner.
The Lower Ark district provided 1,160 acre-feet of replacement water to make up for calculated deficits caused by sprinklers on 107 farms under Rule 10 plans this year. Most of the sprinklers are located on the Fort Lyon Canal. Those included 81 ponds, which were presumed to leak at a rate of about 10 percent under the state formula.
But a study of 20 ponds by engineers Jerry Knudsen and Brian Lauritsen shows they leaked anywhere from 3-45 percent, averaging about 18 percent. Those numbers were used in the state calculations, but only for ponds that were measured.
Ponds with higher leakage tend to crack as they dry up between irrigation runs, Knudsen said. Because of the drought, irrigation runs were less frequent this year, and most of the 50 farmers who attended the meeting expressed doubts that a water-short ditch like the Fort Lyon Canal owed any water to the river under those conditions.
Cutting back the amount of augmentation water needed for the Rule 10 plans is critical to making irrigation affordable. The price of augmentation water is expected to increase, especially in years such as this one when it is not readily available. Water used for this year’s Rule 10 plans ranged in cost from Fry-Ark water, which costs $7.50 per acre-foot, to water leased from the Pueblo Board of Water Works, at a cost of $250 per acre-foot (including storage). Other sources included the Larkspur Ditch and Twin Lakes water owned by the Lower Ark district.
While the cost is going up, water leasing also competes with well groups, said Jay Winner, manager of the Lower Ark district.
“Buying water on the spot market in the future is not promising,” Winner said.