Cotten is first water rules trial witness


ALAMOSA — Chief District/Water Judge Pattie Swift on Monday began a trial over groundwater rules that will affect virtually every San Luis Valley resident from farmers and ranchers to residents who drink from municipal wells.

The rules, awaiting the judge’s order to put them into effect, will require well users — including municipalities — to replace their injurious depletions to surface rights and help bring the Valley’s aquifers back to a sustainable level.

The groundwater regulations, which also include a portion specifying irrigation season dates (April 1-November1), have been in the works for years and were filed with the court under now-retired State Engineer Dick Wolfe in September 2015. Since that time the state has been trying to resolve issues from objectors to the proposed rules or portions of them. Ninety percent of the objectors have worked out stipulated agreements, and a trial that was originally anticipated to last eight weeks is now down to four weeks.

However, 2 J Group still has issues with the rules and specifically the groundwater model the rules depend upon, so a trial of an abbreviated nature is still necessary. 2 J Group is a collection of senior surface water right owners in the Arroya Springs and Arroya Creek area near La Jara in Conejos County.

Attorneys presented opening arguments to the judge on Monday, and the Colorado Attorney General’s office, representing the state engineer, began presenting its case with first witness Colorado Division of Water Resources Division Engineer for Division 3 Craig Cotten.

Judge Swift is presiding over the case at an alternate location, with the Rio Grande Water Conservation District serving as host. Proceedings resume this morning at 9 a.m.

Before the state began presenting its case on Monday, Judge Swift ruled on a motion from 2 J’s attorneys asking the court to exclude evidence regarding the groundwater model, the Rio Grande Decision Support System (RGDSS), as the state has not calibrated the model for Arroya Springs (also known as Diamond Springs), a water supply in Conejos County still at issue with the objectors. The judge denied the motion, and witnesses are anticipated to discuss the model throughout the trial. Judge Swift said she believed she needed to hear evidence regarding the model. She said the argument that the model has insufficient data does not mean it is irrelevant.

Senior Assistant Attorney General Chad Wallace, taking the lead on presenting the state’s case, said the groundwater model is a work in progress that will improve over time, but it is a valuable tool to determine groundwater depletions.

Wallace laid the groundwork of the state’s case through opening arguments and testimony from Cotten. Wallace told the court these rules/regulations are the fourth in a line of water regulations for this basin, beginning with confined aquifer rules restricting new wells, unopposed measurement rules that are providing data for the RGDSS and the Sub-district #1 groundwater management plan. The sub-district, encompassing hundreds of irrigators north of the Rio Grande, has been operating for several years now to accomplish its goals of remedying its injuries to surface water users and replenishing the aquifers, Wallace said.

Wallace said these regulations comply with state legislation requiring efforts to make the basin’s aquifers more sustainable and remedy injuries to senior water rights while not interfering with the Rio Grande Compact, an interstate agreement Colorado has with New Mexico and Texas.

Wallace said the rules need to be approved to comply with Colorado state law and protect water rights.
2 J Group’s attorney Kendall Burgemeister said 2 J Group water users have been negatively impacted by groundwater pumping and do not object to the rules requiring well users to make up for injuries their pumping has caused surface water rights. However, he indicated the rules and model they rely upon are not attributing the declining flow at Arroya Springs to groundwater pumping, which 2 J Group believes is a major cause.

He said the state’s model is not calibrated to Arroya Springs so has no reliable basis to quantify depletions to the springs, and these proposed rules should not be applied to Arroya Springs.

Qualified as an expert witness, Cotten remained on the witness stand through the remainder of the day on Monday and will continue his testimony this morning. He testified about the proposed irrigation season, April 1-November 1 and how the state arrived at those dates, mirroring the natural growing season and historically reflecting that irrigation season in the basin.

Cotten also described irrigation practices and trends, water supply changes and forecasts, history of the Rio Grande Compact and the various rules the state had enacted in the basin over the years such as the well measurement rules. He testified about the development of surface water rights (which were over appropriated by 1900), groundwater development in the basin and the need for groundwater rules and a model to help administer them, and river flows and how they have declined over time.

Cotten also testified specifically about the Arroya Springs area and related ditches and referred to historical documents describing the springs, which date to 1889.

Before released for the day, Cotten spoke about the development of the proposed groundwater rules and how the state engineer enlisted the assistance of a 56-member advisory committee to create the rules. The group met 25 times between 2009 and 2015. He said a technical advisory committee or peer review committee had been working even before that time to develop and improve the groundwater model.

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