Freese and Nichols conducted a Wastewater Master Plan for McAllen Public Utility (MPU) to provide a 20-year Capital Improvement Plan for the largest city in the Rio Grande Valley. Freese and Nichols converted the AutoCAD mapping to GIS and used it along with the H20MAP SWMM model selected through a workshop with the City and GPS survey of every third manhole to construct an up-to-date wastewater model, including 53 lift stations. The updated wastewater line and manhole data was delivered to the Utility in a geodatabase with the data source for the invert elevations flagged (as-built, survey, model or inferred). The updated model development included special detail surveying of special structures and 25 of the larger lift stations included within the wastewater system model.
Freese and Nichols evaluated deep gravity lines versus lift stations and force mains. Additional evaluations included:
Potential need for and timing of a second wastewater treatment plant
Cost of extending wastewater service to the far northern and southern portions of the MPU’s wastewater CCN