Despite years of retiring wells, unconfined aquifer shows little sign of bouncing back – Alamosa Citizen

When the state of Colorado created the Groundwater Compact Compliance Fund with $30 million earmarked for recovering the aquifers of the Upper Rio Grande Basin

When the state of Colorado created the Groundwater Compact Compliance Fund with $30 million earmarked for recovering the aquifers of the Upper Rio Grande Basin, there was an intention to steer a good portion of the money toward irrigators working in Subdistrict 1 of the Rio Grande Water Conservation District.

Questioning the Strategy

Whether the strategy will work is under question. Last month’s reading of the unconfined aquifer storage levels shockingly showed it at its lowest point, despite millions in tax dollars that have been spent to retire groundwater wells.

Motivation behind Senate Bill 22-028

The motivation behind Senate Bill 22-028 was to use state tax dollars to continue to dry out farming fields located in the most productive area of the San Luis Valley because that’s where the depleted unconfined aquifer of the Upper Rio Grande Basin runs through. For the past two decades the state Division of Water Resources has been working with Rio Grande Water Conservation District and the farmers and ranchers who operate in Subdistrict 1 to reduce the amount of groundwater they pump each growing season to help recover the struggling aquifer.

The Allocation of Funds

The 2022 state senate bill would bring new money into the effort. Of the $30 million allocated from Groundwater Compact Compliance Fund to the Upper Rio Grande Basin, nearly $14 million has been directed to retire 44 more groundwater wells in Subdistrict 1, with more money likely to come to further the strategy.

Monitoring Groundwater Usage

The state monitors the amount of groundwater pumped with flow meters tied to center pivot sprinklers which water the fields. The meter reading will tell the farm operator how many acre-feet of water they’ve used during the irrigation season, and each fall figures from those flow meters are reported to the state.

The Assumption and Reality

The assumption has been that by reducing the amount of groundwater pumped from the unconfined aquifer, the aquifer would recharge over time. Over the past decade, it appeared the strategy had validity with the aquifer at times showing a bounce back.

Aquifer Storage Levels at a Low Point

Then came the reading from this August which showed the unconfined aquifer storage near its lowest level, and state and local water managers found themselves scratching their heads in disbelief and frustration.

“It is disappointing to see that the aquifer has dropped lower this year. We had hoped to see an increase in aquifer levels, but another lower-than-average river flow year meant that less water was available to recharge the aquifers,” said Craig Cotten, the state division water engineer in the San Luis Valley. 

Approval of a New Groundwater Management Plan

The continued decline in unconfined aquifer levels is the reason the state engineer this year approved a new Groundwater Management Plan that is included in the Subdistrict 1 Fourth Amended Plan of Water Management. The plan was more than a year in the making and still needs approval from the state water court to go into effect. That won’t happen at the earliest until sometime in 2026.

The Ticking Clock

Meanwhile, the clock is ticking.

“It is very concerning, especially given that Subdistrict #1, under its current plan, has just seven more years in which to recover the unconfined aquifer to a sustainable level. If the aquifer has not recovered by then, and if the subdistrict is still operating under its current Groundwater Management Plan, then the State Engineer will have no choice but to curtail all of the non-exempt wells in this area,” Cotten said.

There are several “ifs” in that scenario, all of which should get addressed when the state water court takes up the new Groundwater Management Plan for Subdistrict 1. But again, that’s not until 2026, and the clock, as Cotten mentions, is ticking.

The Concerns of Subdistrict 1 Farm Operators

Amber Pacheco, deputy general manager for the Rio Grande Water Conservation District, said there are 3,614 wells included in the Subdistrict 1 annual replacement plan. The idea that the state would come in and shut those down because farmers couldn’t recover the unconfined aquifer to a sustainable level is the constant worry Subdistrict 1 farm operators work under.

“There is no specific timeline in which the Subdistrict will meet its objective to reach a Sustainable Water Supply by reaching an Unconfined Aquifer Storage Level between 200,000 and 400,000 acre-feet below that storage level that was calculated to exist on January 1, 1976, but it may be 20 years or less depending on the hydrologic conditions following the period the new plan is implemented,” Pacheco said.

Impact on Agricultural Acreage

Take a drive down County Rd E or any of the other country roads that cross through Rio Grande and Alamosa counties and you’ll notice the Valley’s potato harvest in full swing. Take a bit closer look, and in the midst of the harvested fields is a growing amount of agricultural acreage once productive that is now intentionally dried out to save on the groundwater below.

Anticipated Future Dry Fields

With the unconfined aquifer showing little to no bounce back after years of attempted recovery, the expectation is that the western and northern ends of the San Luis Valley will see more dry fields in the growing seasons to come. The money spent through the state’s Groundwater Compact Compliance Fund to retire more groundwater wells will begin to show up in the 2025, 2026 planting seasons and beyond.

As Cotten said, Subdistrict 1 is “one of the most productive irrigated farming areas in the state.” 

Farming with a struggling aquifer is making it less so.

From The Citizen’s water archives:

SDGs, Targets, and Indicators

1. SDG 6: Clean Water and Sanitation

   • Target 6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity.
   • Indicator: Unconfined aquifer storage levels

2. SDG 12: Responsible Consumption and Production

   • Target 12.2: By 2030, achieve the sustainable management and efficient use of natural resources.
   • Indicator: Retirement of groundwater wells

Analysis

The issues highlighted in the article are connected to SDG 6 and SDG 12.

SDG 6: Clean Water and Sanitation

The article discusses the depletion of the unconfined aquifer in the Upper Rio Grande Basin and the efforts to reduce groundwater pumping to recover the struggling aquifer. This aligns with SDG 6, which aims to ensure clean water and sanitation for all. The specific target under this SDG that can be identified is Target 6.4, which focuses on increasing water-use efficiency and ensuring sustainable withdrawals and supply of freshwater. The article mentions the unconfined aquifer storage levels as an indicator to measure progress towards this target.

SDG 12: Responsible Consumption and Production

The article also addresses the retirement of groundwater wells as a strategy to manage and conserve natural resources. This aligns with SDG 12, which aims to achieve responsible consumption and production. The specific target under this SDG that can be identified is Target 12.2, which focuses on sustainable management and efficient use of natural resources. The article mentions the retirement of groundwater wells as an indicator to measure progress towards this target.

Table: SDGs, Targets, and Indicators

Source: alamosacitizen.com