Contract awarded for Arroyo Colorado dredging design project

Stantec Inc. of Denver, Colorado, has won a $1.6 million contract from the U.S. Section of the International Boundary and Water Commission (USIBWC) to design the dredging of approximately 6.3 miles of the Arroyo Colorado, a critical component of the Lower Rio Grande Flood Control Project (LRGFCP).

The contract is for two years and focuses on the stretch of the arroyo between U.S. Business Highway 77 and Cemetery Road within Harlingen, Texas.

According to Dr. Maria-Elena Giner, P.E., USIBWC Commissioner, this award is a big step towards improving the Lower Rio Grande Valley’s flood control system. 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 spite of the fact that the the USIBWC flood control project worked as it was supposed to during the recent heavy rain, the Arroyo Colorado’s flood conveyance capacity has been gradually diminishing due to sediment build-up.

The LRGFCP starts in Peñitas and extends downstream along the Rio Grande to Brownsville. During heavy rainfall, the system is designed to divert up to 105,000 cubic feet per second (cfs) into the Main Floodway, upstream of Anzalduas Dam.

From the Main Floodway, 20 percent of the flow, or 21,000 cfs, goes into the Arroyo Colorado. The remaining 80 percent goes into the North Floodway. Flows from the North Floodway and Arroyo Colorado drain into the Laguna Madre.