COLORADO is estimating 750,000 acre-feet on the Rio Grande and 405,000 acre-feet on the Conejos River, both dramatically up from a year ago thanks to healthy snowpack in the San Juan Mountains, State Engineer Kevin Rein told the Rio Grande Compact Commission on Friday.
“Forecasted river flows are much better this year, especially for the rivers starting in the San Juan Mountains,” Rein said. “Streamflows from the San Juan Mountains are estimated to be 130 to 250 percent of the last 30-year average.”
The Sangre de Cristo Mountains are at near average snowpack conditions, but still better than recent years, Rein said.
Streamflows on the Trinchera, Culebra, and Crestone creeks are forecasted at 90 to 120 percent of the last 30-year average, he said.
In 2022, the Rio Grande had 442,000 acre-feet and the Conejos 266,000 acre-feet for a third straight year of below average stream flows.
Rein’s presentation to the Rio Grande Compact Commission, which manages water on the Rio Grande for the states of Colorado, New Mexico and Texas, included a report on the San Luis Valley’s subdistrict system and Colorado’s groundwater pumping rules that Valley irrigators have to follow.
Subdistrict 1, which is the biggest land subdivision in the San Luis Valley with 3,000 water wells and where farmers hold contracts with entities like Coors, Walmart and Safeway, has submitted a fourth plan of water management to Rein and the Colorado Division of Water Resources in its effort to meet the sustainability requirements for Upper Rio Grande’s unconfined aquifer.
“It is struggling with meeting its sustainability requirements in the unconfined aquifer,” Rein told the Rio Grande Compact Commission.
The proposed fourth plan of water management by Subdistrict 1 would require irrigators to cover groundwater withdrawals with natural surface water or through the purchase of surface water credits. The plan calls for a 1-to-1 augmentation, meaning for every acre-foot of water used, an acre-foot has to be returned to the unconfined aquifer through recharging ponds.
In the San Luis Valley, well owners must replace their injurious river depletions by participating in a subdistrict or by getting a court-approved augmentation plan. The subdistricts, governed by the Rio Grande Water Conservation District, must get state approval for annual replacement plans that show how farmers and ranchers are covering their water depletions.
There are three upcoming state water court cases involving irrigators in Subdistrict 1 who filed their own augmentation plans in an effort to stay out of the subdistrict.
The largest of the three cases involves the Sustainable Water Augmentation Group (SWAG), which consists of 17,000 irrigated acres in Subdistrict 1. That case is set for a five-week trial in July and will be closely watched to see how a proposed augmentation plan this large is reviewed by state water court.