Carlos Rubenstein, Rio Grande watermaster, said rains have reversed further depletion of the combined reservoir levels at Falcon and Amistad Dams and promoted spill events at the Anzalduas Dam pool, allowing for several periods of no-charge irrigation water for irrigation districts.
"Combined reservoir levels will go up," said Rubenstein. "I suspect they will be above 34 percent and approaching 35 percent. We were at 25 percent a year ago this week, so we're better off, but you have to temper that by saying we're better off than last year, with last year being a record low year. We still have a lot of room in which we can store water."
Total gains to reservoir levels ending July 15 have not yet been compiled, but Rubenstein suspects they will be sufficient to allow for the first allocation in three months for the Valley's 29 irrigation districts, which supply water to farms, industry and municipalities.
Allocations occur when reservoir water levels rise sufficiently to replenish, or revise upward, the amount of water each water district has in its "account," or in storage behind the dams.
"The rain events have been beneficial in letting us conserve a lot of water in the lakes (reservoirs), plus it's also reduced our evaporation levels, so I would expect that next month, we'll be able to have another allocation as well," Rubenstein said.
Ruben Quintanilla, river operations manager, said beginning the 4th of July weekend, his office has allowed irrigation districts on several occasions to temporarily withdraw water from the river at no charge to their accounts.
No-charge water is made available to districts when inflows to the pool at Anzalduas Dam, near Mission, begin to spill.
No-charge water can be of tremendous benefit to water districts if individual district reservoirs have the capacity to store the almost-free water. Districts are actually charged a nominal 26 cents per acre-foot of water, versus the normal charge of between $30 to $48 per acre-foot. Most districts in the Valley have their own reservoirs, of varying capacities.
For Jo Jo White, manager of the Mercedes irrigation district, the recent no-charge water events have been of tremendous benefit to his district. The water came at a time when his reservoir was purposely left low, to take advantage of just such an opportunity.
"I'm fortunate in that I have a big storage capacity," he said. "If I'm fairly empty, I can put up to 6,000 more acre-feet of water in there. That's enough to irrigate 8,500 acres. By keeping my reserve as low as possible and just ordering my water when I need it, I've been able to pick up a lot of no-charge water that really helps subsidize our district's water."
White said that if no-charge water is still available after his reservoir is full, he'll pass on the water to irrigators without charging their accounts.
"If the water is not going to be charged against us, and there's a demand for water by irrigators in our district, like there is now because we haven't gotten the rains other areas have, we'll pump it to them."
White recalled that in years past, when water was plentiful, no-charge water was sometimes used to flush out the river, reducing levels of salt before flowing out to the Gulf of Mexico.
"The idea behind this no-charge water now," said Rubenstein, "is to put as much of the unanticipated inflows to beneficial use, because for every drop that we give out at no-charge, it's a drop that we conserve behind Falcon Dam."
Rubenstein said no-charge water used by water districts last year totaled almost 79,000 acre-feet of water, roughly the amount of water used in three months by all municipalities in the Valley combined.
Totals for this year, prior to July 4, were at 12,000 acre-feet of water. An acre-foot is the amount needed to cover an acre of land with one foot of water, or 326,000 gallons.
Rod Santa Ana III is a writer for Texas A&M University