Groundwater pumping by growers upstream is draining Pecos River
Copyright © 2013 Albuquerque Journal
For the third year in a row, the New Mexico Interstate Stream Commission’s $100 million system to deliver water to Carlsbad-area farmers has failed.
State officials blame drought. Critics say the system is flawed because its design was based in part on data from a period of unusually wet weather.
Whatever the root cause, the network of wells installed to pump groundwater to the Pecos River for the farmers’ use will deliver less than half the water it is supposed to this year, according to a mid-July estimate by the state.
“The drought we’re in right now – it is the record-setter,” Interstate Stream Commission director Estevan López said in an interview.
That has led to farmers in the Carlsbad Irrigation District with little water for their crops, and a legal battle over who bears responsibility for living up to the state’s water rights obligations.
Critics say a part of the system’s problem is that its designers did not include an extreme drought, such as the previous-worst drought of the 1950s, in the computer model used to estimate how much pumping would be needed. The model used historical data from 1967-1996 for the system’s design – an unusually wet period in southeast New Mexico, according to the National Climatic Data Center.
That system design used weather, river flows and water use during that 1967-1996 period to project how much water would be needed to meet New Mexico’s future obligations to deliver water to Texas under the Pecos River Compact while also keeping the water flowing to Carlsbad farmers. But there was no 1950s-style drought during the 1967-1996 period.
“There was a flaw in the model at least to the extent they did not include a drought,” Dudley Jones, executive director of the Carlsbad Irrigation District, said in an interview.
Greg Lewis, Pecos Basin manager for the New Mexico Interstate Stream Commission, defended the model, saying the 1967-1996 period was the only time period for which the state had adequate data on groundwater pumping and irrigation use in the valley, which was needed to estimate future water needs.
The groundwater pumping system is part of a deal struck in 2003 among the state and two Pecos River irrigation districts. Extensive groundwater pumping for farming in the Roswell-Artesia area was depleting flows in the Pecos River, hurting Carlsbad-area farmers who were downstream as well as leading to a deficit in the state’s obligations under the Pecos River Compact to deliver water to Texas.
The Carlsbad farmers generally have senior water rights, meaning their farmlands were the first to put the Pecos water to use in the area, and without a deep aquifer of their own they rely primarily on river water to irrigate their crops. Under state law, they have first call on the water over most of the groundwater pumpers upstream in the Roswell-Artesia area who came later and whose pumping was alleged to be causing the river’s shortfalls.
Rather than simply cutting off those Roswell-Artesia pumpers, the state Legislature appropriated some $100 million to try to fix the problem. The money was spent to reduce water use in the Pecos Valley by buying up agricultural water rights and taking the land out of production. The state also spent money to build well fields north of Carlsbad to pump groundwater into the Pecos in dry years for use by Carlsbad farmers.
The first goal continues to be met, with the state currently running a surplus in its deliveries to Texas, López said.
But the first time the system’s ability to meet the second goal was tested, in 2011, it fell well short of delivering the water the state had pledged to Carlsbad farmers.
The system’s design called for a capability to pump as much as 35,000 acre feet of water in a single year. An acre foot is the amount a farmer needs to irrigate an acre of land to a depth of one foot.
In 2011, the system pumped just 13,089 acre feet of water, less than 40 percent of the target.
In 2012, that rose to 18,746 acre feet, still far short of the amount of water needed to meet the state’s obligations to Carlsbad farmers under the agreement.
This year, the state has so far pumped 10,139 acre feet of water, and there is no chance it will meet its target for delivering water to Carlsbad farmers, according to Lewis.
A call to cut off upstream users
The pumps have fallen short because water use during the drought has substantially lowered the aquifer from which they are drawing groundwater, López said. At the same time, the drought also has decreased flows in the Pecos, driving up the demand for river water, he said.
According to Jones, when the system was being designed, Carlsbad farmers expressed concerns about the risk it would not provide enough water during a drought. State officials assured them the state’s research and the computer model used to design the water system showed there would be enough water, Jones said.
With its ditches empty, the Carlsbad Irrigation District’s board in April issued a formal request to the state of New Mexico for a “priority call” on the Pecos, demanding the state shut down the upstream water users who they say are depriving them of irrigation water. The situation has led to some hostility, as Roswell-Artesia farmers continue to pump groundwater while the Carlsbad farmers’ irrigation ditches are dry.
But state water Engineer Scott Verhines has said the state does not have the procedures in place to cut off the Roswell-Artesia farmers. Talks are now under way among officials from the state and the two irrigation districts to determine how to resolve the priority call question.