Dell Valley Farming, and Groundwater Pumping, Continued to Expand in 2014 – Water District to Set Irrigation Allotments in early 2015
Farming expanded in Dell Valley in 2014, with land in cultivation growing by about 1,000 acres and groundwater use reaching levels that have not been seen in the Valley for decades.
Directors of the Hudspeth County Underground Water Conservation District #1 reviewed the data at a meeting Tuesday (Dec. 9). Based on the data, the board members will vote early next year on the amount of water to be allocated to farmers for 2015 and 2016.
At present, district board members appear on course to leave the allocation unchanged, at 4 acre-feet per acre of permitted land.
Increased pumping has had an impact on water levels in the Bone Springs-Victorio Peak Aquifer, and, since 2009, data has indicated a downward trend in the aquifer level of between 1.5 and 2 feet per year. But even as irrigation expanded in 2013 and 2014, a break in drought conditions has benefited irrigators, as monsoon rains recharged the aquifer. At Tuesday’s meeting, Al Blair, the district’s hydrologist, told board members that water levels were down about half a foot from the same time in 2013.
Blair used data from NASA satellite images to estimate the amount of acreage in cultivation in 2014 – and extrapolated from that figure to estimate the amount of water pumped. Satellite images indicate that about 21,900 acres were cultivated in the Valley in 2014, up from about 21,000 the previous year. Much of the increase in cultivated land has occurred at HDR Farms and Par 5, which are operated by dairies based in Dexter, N.M. and grow alfalfa for those operations.
Based on the acreage figure, Blair estimated that about 88,000 acre-feet of water were pumped from the aquifer in 2014. Though data in 2012 suggested even higher estimates for water usage, Blair said that pumping in 2014 “should be an all-time high, at least relative to the last 15 years.”
The water district sets the allotment for farmers every two years, and the board is scheduled to vote on the allocation at its March 2015 meeting. However, the board will likely reach a consensus on the allotment sooner – perhaps at its Jan. 13 meeting – in order to allow farmers to plan for the 2015 season.
According to the district’s rules, the board must act to cut the allotment from 4 to 3 acre-feet per acre if the average water elevation over the two-year period falls below 3,560 feet, Blair said. Though full water-level data for 2014 is still pending, Blair said the two-year average is likely to be just a half a foot above that threshold. In the absence of the major local rains that occurred in September 2013 and September 2014, the water elevation would almost certainly have fallen below the threshold, Blair said.
Most of the recharge in the Bone Springs-Victorio Peak Aquifer occurs through rain and snowfall in the Sacramento Mountains in New Mexico, hydrologists say, but rains in and around Dell Valley can also impact water levels. In most aquifers, water moves through sand or gravel, but hydrologists describe the aquifer that underlies Dell Valley as a kind of underground river, with water flowing rapidly through caverns and openings in limestone.
When the average water elevation falls between 3,570 and 3,560 feet, the district can opt to set the allotment on a pro-rated basis, which under the current water levels would mean an allocation of 3.11 acre-feet per acre for 2015 and 2016.
Reducing the allotment from 4 to 3 acre-feet per acre would likely have limited impact on the total amount of water pumped in Dell Valley, Blair said. There are water rights for thousands of acre-feet that are currently not being exercised, and if the allotment were cut, farmers would likely move to purchase or lease those water rights from the owners, in order to continue their current levels of operation. Blair said the water district might have to reduce the annual allotment as low as 2 acre-feet to substantially reduce the amount of overall pumping in the Valley.
Water district board members have voted to pursue a policy of sustainability in groundwater management – meaning they would like to see water levels remain unchanged, or decline only slightly, during the next 50 years. The current level of pumping is likely not compatible with that goal, Blair said, and board members acknowledged Tuesday that irrigation in the Valley is effectively “mining” the aquifer. According to a “modeled available groundwater” study, or MAG, conducted for the aquifer, a sustainable amount of pumping would be about 65,000 acre-feet per year. Blair said that while the MAG study was imprecise, preserving current water levels would likely require reducing pumping to somewhere near that figure.