With flooding reports at more than eight feet along East Main Street under the Missouri Pacific Railroad Bridge, the City of Grand Prairie selected Pacheco Koch to prepare an expedited investigation into the problem. With public safety a major concern, the City required a quick turnaround on conceptual design in order to begin construction as soon as possible. Never one to waste time, Pacheco Koch set immediately to work.
A combination of dye testing and CCTV were utilized to determine the location and sizes of undocumented storm infrastructure lines. A 2D-hydrodynamic analysis was conducted to model a privately owned detention pond and determine the extent of existing sump flooding for multiple frequency storm events.
Two alternative storm sewer alignments were developed to resolve flooding issues. The existing infrastructure was incorporated into the design to minimize construction costs. Conceptual design included coordination with TxDOT, Union Pacific Railroad, franchise utility companies, and adjacent land owners; review of permitting requirements and development of Opinion of Probable Construction Cost for each alternative. An alignment was selected to minimize utility conflicts and reduce property acquisition. Final design includes 1,500 linear feet of storm sewer, 600 linear feet of 12-inch water line relocation, and relocation of two fiber optic duct banks. This project demonstrates our ability to quickly and efficiently investigate and design complex storm water projects, with multiple stakeholders and governing authorities.