McALLEN, Texas (Border Report) — A Colorado company will design the dredging of a section of a South Texas waterway that flooded during historic recent rains, the U.S. International Boundary and Water Commission says.
Stantec Inc., of Denver, has been awarded a $1.6 million contract to design the dredging of 6.3 miles of the Arroyo Colorado, the IBWC announced.
The two-year contract will focus on an area of the arroyo, or channel, located in Harlingen, Texas, between U.S. Business Highway 77 and Cemetery Road, near the border with Mexico.
The area is what the IBWC calls a “critical component” of the Lower Rio Grande Flood Control Project, yet it had “reduced capacity” when it was needed most during recent flooding, the head of the IBWC says.
Historic rains hit the Rio Grande Valley region overnight on March 27, and the Arroyo Colorado, which was supposed to help alleviate flooding, itself also flooded.
In Harlingen, 21 inches of rain fell. Special diversion gates operated by IBWC were opened on March 31 to relieve excess water from the region’s main drain.
The Arroyo Colorado flooded after historic rains surpassing 20 inches struck Harlingen and the Rio Grande Valley overnight on March 27, 2025. (KVEO Photos)
The Arroyo Colorado was supposed to act as an emergency water evacuation route to reduce water in the region’s Main Floodway and take water to the Laguna Madre, near the Gulf.
But it didn’t remove water quickly because of excessive debris in the watershed as well as overgrown vegetation on the banks, U.S. IBWC Commissioner Maria-Elena Giner said.
Some housing subdivisions and roadways were flooded and at least two deaths were reported in the weather event.
Giner came to South Texas and toured the region on April 5. Afterwards, she held a town hall meeting in Mercedes, Texas, with local stakeholders and irrigation district managers and at the time promised that her agency would contract the dredging to clear the Arroyo Colorado for future use.
“I was really shocked by this rain event,” Giner told them. “It was just unbelievable. My phone was blowing up.”
The IBWC admitted the Arroyo Colorado did not function as intended.
“During my recent visit to some of the hardest hit areas from last month’s historic rainstorm, I observed first-hand the Arroyo Colorado’s reduced capacity. I promised government officials as well as irrigation managers that we would do everything possible to help improve the Lower Rio Grande Valley’s flood control system,” Giner said in a statement this week. “This award is a big step in that direction. Removing accumulated sediment from the Arroyo Colorado will reestablish its design capacity and help communities get rid of excess water before it can cause damage.”
In October, Stantec was awarded a contract with the the U.S. Army, according to Department of Defense records.
The arroyo is part of the Lower Rio Grande Flood Control Project that encompasses 180 miles of the Rio Grande in three border counties — Hidalgo, Cameron and Willacy. It spans from the border town of Peñitas, Texas, to near the Port of Brownsville, according to the IBWC.
During heavy rainfall, the system is designed to divert up to 105,000 cubic feet per second of water into the Main Floodway, upstream of Anzalduas Dam, in Hidalgo County. From the Main Floodway, 20% of the flow, or 21,000 cubic feet per second of water, is to go into the Arroyo Colorado. The remaining 80% is to flow into the North Floodway and all to drain into the Laguna Madre.
Sandra Sanchez can be reached at SSanchez@BorderReport.com.
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