GCTA: Laredo’s Storm Sewer Outfall Rehab Discussed

By Traci Read, Senior Editor | April 2009 Vol. 64 No. 4
Riazul Mia of Environmental Services for Laredo, TX

Riazul Mia, director of Environmental Services for the city of Laredo, TX, addressed the bi-monthly meeting of the Gulf Coast Trenchless Association on Feb. 11, in Houston.

Mia shared with attendees experiences gained on the “River Road Storm Sewer Outfall Rehabilitation Project” in the city of Laredo, TX, to rehabilitate a 120-inch corrugated metal pipe (CMP) storm sewer trunkline. The city used rehabilitation technology to repair a 114-inch ID corrugated metal pipe storm sewer outfall into the Rio Grande. The host pipe was installed in the 1970s using open-cut through a landfill area that prior to this project was beginning to fail in several areas.

“The storm sewer serves an extensive drainage system through an older section of the city of Laredo near the Gateway to Americas International Bridge which is one of the city’s five international bridges to Mexico,” said Mia. “The project addresses many utility and environmental issues among which is crossing a former landfill area. The existing storm sewer has a depth of cover more than 20 feet below the surface along certain sections of the project. The existing storm sewer line also transverses densely compacted residential and commercial areas including the Rio Grande Plaza Hotel, a Laredo landmark, before the line outfalls into the Rio Grande. Additionally, numerous public facilities would be impacted by any open-cut construction.”

Mia said that “the use of both trenchless methods reduced the construction schedule to such an extent that the liner, extending over 1,000-feet, for the host pipe (not including the grout) was installed in less than one month.”