McAllen, Texas (AP) — On a scorching afternoon in southern Texas, Sonia Lambert overlooked an outdoor canal carrying muddy green water from the Rio Grande River to nearby towns and farmlands. road.
“It will be a problem for someone else,” Lambert said, referring to her next retirement as the head of an irrigation district near the US-Mexico border.
In the Lower Rio Grande Valley, a canal system designed for agriculture over a century ago still supplies water to the region’s lush farmlands and fast-growing towns and cities. Today, canals lose as much as 40% of their water. Experts say that as the population grows and climate change intensifies the drought, it could lead to sharp water shortages in the coming decades.
“The region remains dry due to climate change, which significantly reduces water supply,” said Guy Fipps, a professor of irrigation engineering at Texas A & M University, who has been studying water systems since 1998. ..
State water authorities predict that water demand in cities and towns in the region will double over the next 50 years. For decades, McAllen has evolved at a fast pace, attracting new entrants to large free-trade areas and engaging in health care, education and retail. Between 1990 and 2020, McAllen and its neighboring cities, Edinburg and Mission, increased six-fold to nearly 871,000, according to the US Census Bureau. Similarly, the cross-border Mexican cities of Reynosa and Matamoros grew rapidly after the establishment of US-owned assembly plants in the mid-1990s.
A more complex issue is the 1944 treaty between the United States and Mexico, which defines how countries share water from the Rio Grande. Mexico is expected to send 350,000 acre-foot of water to the United States each year. This is enough to supply 700,000 households. However, due to drought, water scarcity and the thirsty crop industry in northern Mexico, these obligations cannot be met on a regular basis and delivery is delayed.
Delayed delivery is a source of frustration, but US water managers and farmers are quickly aware of the big challenges in the country.
Over 2,000 miles (3,219 kilometers) of pipelines and canals (approximately 100 feet (30 meters) wide) in the region are intended for large-scale, rare deliveries to agricultural land. Common modifications to modernize and make waterways more efficient (some attempts have been made in many districts) include concrete lining of soil canals and more use of water by farms with meters. It involves close monitoring. Another option has a larger price tag. Is to replace the canal with an underground pipeline. Underground pipelines lose much less water and are suitable for servicing cities.
Lambert, irrigation district manager in Cameron County, said it would cost $ 250,000 to $ 1 million to convert a mile of an outdoor canal into an underground pipeline. She said her district could only carry about one-fifth of the 250-mile (402-kilometer) canal underground in the last two decades.
“It’s just an amount that the agricultural community couldn’t support,” Lambert said.
Since the early 1900s, a network of about 20 independent irrigation districts has served farmers, cities and towns in the area. However, as McAllen devoured much of the surrounding farmland, some officials wanted more control over the waters they said would charge the city too much for water.
Still, the higher fees charged to urban water utilities are often the way irrigated districts pay for canal repairs, Phipps said. This means that water bodies that serve large cities are generally more advanced in keeping their canals up to date.
Still, the Rio Grande Valley water system and farms are linked by the same aging system.
Since cities and farms get water from the same canal, hydrologists and water authorities say that the reduced flow of the Rio Grande and low reservoir levels can ultimately cause problems for everyone in long-term droughts. Say there is sex. When there is little water in the canal, it is more likely to be lost due to evaporation and infiltration. And all shares of water are threatened.
Experts already say that the demand for water from rivers exceeds the supply.
Small towns with relatively low water supplies can be particularly affected during severe dry periods, and their irrigated areas are less likely to have funding to repair or replace canals.
“This is a rare situation, and agricultural canals are being used to help supply urban water,” says Phipps.
Over time, experts say farms in the area will face severe water shortages and will be forced to make more difficult choices. This scenario has already been deployed in parts of the western United States. Over the years, some irrigation districts have received state or federal funding through settlement-managed repair grants, but water managers, farmers, and hydrologists are comprehensive. They say they don’t have enough money to repair. By 2070, the Texas Water Development Commission predicts that the water used to irrigate lower Rio Grande Valley farms will be reduced by 36%. This is mainly because more farmland is being replaced by urban development.
In the countryside of Cameron County, Lambert already has a glimpse of its future. Earlier this year, Lambert told sugarcane farmers in her area that she could only get one water supply instead of two, before the rain hit the area.
To save thirsty crops, some farmers bought water from neighboring districts for tens of thousands of dollars. Others have removed more than 100 acres of crops. A few weeks later, the sky opened.
When asked how much water a farmer can receive next season, Lambert says she often doesn’t have an answer.
“That’s a million-dollar question asked by our farmers, and I have no idea of the world,” she said.
Editor’s Note — This is the third story in an occasional series that looks at the interaction between population growth and climate change.
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