McALLEN, Texas (Border Report) — The head of a South Texas planning group is proposing that a “water bank” be formed so smaller cities can get water from larger cities with surplus supplies and keep it flowing in South Texas.

Jim Darling is chairman of the Region M Water Planning Group for the Texas Water Development Board, and a former mayor of McAllen, one of the largest cities in the Rio Grande Valley. He was in Austin on Wednesday speaking with officials from the Texas Commission on Environmental Quality to pitch this idea and to talk to them about solutions to the ongoing drought, and lack of water payments from Mexico, he told Border Report.

“I’m trying to get three or four cities to be the lead on that, larger cities, and actually organize it through the Council of Governments,” Darling said.

Mexico and the United States have an international treaty that obligates both nations to make certain amounts of water payments across the border during a 5-year cycle. The current cycle ends in October 2025, but Mexico has paid barely one year’s worth of water that it owes the Rio Grande, so far this cycle.

And that has officials on the border worried as triple-digit temperature days are forecast and little rain is in sight.

Many agriculture growers already have lost water supplies but municipalities have not. Without the volume of water from agriculture pushing the municipal water through the open canal system, Darling says he worries there won’t be enough water flow to get the water to treatment plants.

“I’m really worried about that. Where are you gonna get that push water from? Some water is available in the river, but you have to buy it from ag. It’d be expensive and how’s all that going to work? So we’re asking the water masters office to come up with a bank, if you will. So, at least if your water district is out of water right now, they can’t, they’re not going to pump. So you can get the water from the river up your canal,” Darling said.

A large percentage of water is lost through the region’s open canal systems through conveyance, and the triple-digit heat and dry days are continuing to add to evaporation problems.

Lining the canals to prevent evaporation has been proposed, Darling told Border Report, but he said there are over 3,000 canals in Hidalgo and Cameron counties and there isn’t time or resources to line the infrastructure right now.

Combined capacity at the region’s two reservoirs on Wednesday was hovering just above 20%. But Falcon Reservoir, in Zapata County, was only 8.9% full. Amistad Reservoir, outside Del Rio, was at 27.9%, according to the Texas Water Development Board.

A sugar mill in Santa Rosa — the only one in Texas — shut down earlier this year due to a lack of water for growers.

Hidalgo County has declared a disaster declaration due to the drought and lack of water payments from Mexico.

And several cities on the border have implemented Stage 2 water restrictions that allow homeowners to water lawns only on certain days.

Darling says if combined water levels at the reservoirs drop below 20%, he expects additional restrictions will be implemented.

Sandra Sanchez can be reached at SSanchez@BorderReport.com.