State Throws More Weight to Water Study

By Chris Woodka, The Pueblo Chieftain, Colo.

Jan. 26–DENVER — Colorado will spend $300,000 from a legal fund established to protect interstate compacts in an effort to glean data from a project that measures moisture in the soil at the Colorado State University Rocky Ford research station.

The funding was approved this week by the Colorado Water Conservation Board, at the request of Attorney General John Suthers, after the board earlier authorized $90,000 last year to help finish construction of a lysimeter to measure water use specific to crops in the Arkansas River Valley.

Since 2004, the CWCB has contributed $750,000 to programs designed to use the data from the lysimeter to reduce Colorado’s water debt to Kansas.

“We told you we’d never ask for operating funds, but here we are,” CWCB staffer Steve Miller told the board Wednesday. “Our efforts to get federal funding were not successful. We weren’t able to tap into that funding.”

The lysimeter project also failed to pass CWCB muster through the statewide water supply reserve account, even though it was approved by the Arkansas Basin Roundtable. The state made pitches to local conservancy districts in 2006. While valley officials voiced support for the project, they took a wait-and-see approach to funding.

The $300,000 is not strictly operational funding, he added.

Colorado hopes to use the data to adjust formulas that measure water use in the Arkansas Valley with more localized crop information. Besides data from the lysimeter, weather data from a network of stations up and down the valley will be factored in as well.

The lysimeter is a 10-foot cube of dirt that sits on top of truck scales. The device can weigh the soil and water applied to crops, which are planted on the scale. It can accurately measure how much water evaporates, is used by plants and drains through the soil.

Over the next three years, water use by alfalfa — the most widely grown crop in the valley — will be measured. Other crops will be evaluated in future years.

Ironically, federally funded lysimeter data from other states, which have different growing conditions than Colorado, were used to determine the formulas for consumptive use agreed to by Kansas and Colorado as part of the Arkansas River Compact settlements in a U.S. Supreme Court case.

Part of the $300,000 will also be used to establish a second, smaller lysimeter at Rocky Ford, which will be used in ongoing studies of crop water use.

“This part of the project is critical,” State Engineer Dick Wolfe told the CWCB. “If we can prove our crop consumption is less than we agreed to, this will reduce our obligation to augment well pumping. If we can show it for alfalfa, it will go a long way toward that goal.”

Colorado State University pays for the basic operation of the lysimeter, but in order for the data to be meaningful in the compact case, it has to pass professional scrutiny, Miller explained.

“We need a peer-reviewed document to submit to arbitration,” Miller said.

Kansas v. Colorado is close to being finalized by the U.S. Supreme Court after more than 22 years of litigation. Disputes in the future will be decided by an arbitrator, rather than the contentious court battles and intense arguments before a special master that have marked recent years.

The CWCB has about $2 million available in its interstate compact litigation fund, and won’t likely need to increase the amount this year.

Using some of it for the lysimeter is appropriate, Suthers said.

“Establishing the appropriate reference crop (alfalfa) coefficient is essential to preventing an overstatement of Colorado’s obligations under the decree in Kansas v. Colorado, and is a necessary and appropriate use of the fund,” Suthers wrote in a Jan. 11 memo. “Separate subsequent research may be undertaken to determine appropriate crop coefficients for the other major crops in the Arkansas Valley.”

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