Background

In 1998, the City of Donna provided water service to about 99% of its residents, while many of the 20 colonias surrounding the city received water service from two private water supply corporations (WCS).  The Donna water plant built in 1918 and upgraded in 1947 and 1987, had the capacity to treat 3.42 million gallons per day (mgd), which was considered insufficient to meet the future water needs of this rapidly growing community. In addition, the plant had been cited for numerous violations by the Texas Commission on Environmental Quality (TCEQ). The City also provided wastewater services to approximately 50% of the population. Its wastewater treatment plant had a capacity of 2.3 mgd, which was insufficient to meet the needs of the growing population, as well as the colonias, which did not receive service. Colonia residents often used septic tanks or open-pit privies to dispose of their sewage, which resulted in contamination of surface water resources.

Project Scope

Phase I water system improvements consisted of the construction of a new water treatment plant with a capacity of 4.5 mgd, an elevated storage tank with a minimum capacity of 200,000 gallons and an interconnection with the North Alamo WSC to provide an additional 1.5 mgd of treatment capacity, as well as expansion of the water distribution system to serve six colonias. Phase II improvements included replacing deteriorated waterlines. Wastewater system improvements consisted of increasing treatment capacity from 2.3 to 2.7 mgd, eliminating 10 of the 13 existing lift stations, replacing two of them and building a new lift station in the south colonia area, as well as expanding the collection system to accommodate additional flows and extend service to the surrounding colonias.

Benefits

The project provided a more sustainable and reliable drinking water system in compliance with state regulations for the entire community. In addition, first-time wastewater services were extended to 500 households in surrounding colonias, reducing the health risks associated with waterborne diseases by collecting and treating 210,000 gallons per day of wastewater. Moreover, reducing the number of wastewater lift stations from 13 to 3 improved the operational efficiency of the utility by reducing its maintenance requirements, energy consumption and operational costs.