From The Pueblo Chieftain (Chris Woodka):
Farmers said all along that the state undershot the amount of water lost to leakage from irrigation ponds.
The final numbers confirm that suspicion, showing the rate is double the original assumption.
“We’re not going to celebrate until we get it in writing,” said Don McBee, who nevertheless was clearly pleased with the results.
McBee, a Lamar farmer, and his neighbor Dale Mauch challenged the Colorado Division of Water Resources assumption that ponds used to feed irrigation sprinklers leaked only about 2 inches per day. A stipulation to 2010 irrigation improvement rules allowed for the formula to determine depletions from sprinklers to be changed if scientific evidence showed the number was wrong.
McBee and Mauch were members of a panel formed in 2008 to advise State Engineer Dick Wolfe on how the rules would be drafted. From the first meeting, they said the state was underestimating pond leakage. Since then, they have urged more study and conducted tours of ponds for state officials.
A three-year study sponsored by the Lower Arkansas Valley Water Conservancy District concluded that the actual median leakage is more than 4.2 inches per day, regardless of weather conditions.
In fact, the number means farmers on the Fort Lyon Canal could owe very little water to the Arkansas River when the leakage is plugged into the depletion formula, said Jack Goble, engineer for the Lower Ark. “It’s a drastic difference,” Goble told the Lower Ark board this week, showing how the rules would have affected irrigation over the past 20 years. “There are still months when the Fort Lyon owes water, but it’s pretty rare.”
A two-year study last year was only partially accepted by the state because not all meters were properly certified. Interim numbers were adopted for 2015.
The new study includes data from three years, 2013-15, during which weather conditions shifted from dry to wet. Data were collected from 23-29 farms with more than 750 measurements. Most were on the Fort Lyon Canal.
The Lower Ark’s proposal to the state would provide more flexibility for frequency of irrigation as well, reflecting the number of days the ponds were filled.
“We will incorporate the data for the Fort Lyon Rule 10 plan this year,” said Bill Tyner, assistant division engineer. “We’re working on a provision to use the factors with owners not in the Fort Lyon plan.”
The state is working on the memorandum of understanding with the farmers and the Lower Ark district to make the numbers permanent.
There also will be periodic testing to verify the formula, and the tests will not be burdensome to farmers, Tyner added.
The farmers still must pay a fee to develop the annual plans, but will save money because of the need to purchase less replacement water.
“All of these efforts have been a huge benefit,” said Lynden Gill, chairman of the Lower Ark board. “When we started, there was a big wall in front of us. Now, things have come together.”
