Melissa North Elevated Water Storage Tank

Client: City of Melissa Texas
Project Type: Roadway Design, Geotechnical Engineering, Water & Wastewater Design, Storm Sewer & Hydraulic, ADA Compliance

About this Project

Melissa, Texas is a rapidly growing community on the north side of the Dallas Metroplex. To meet its required future water needs, Melissa needed to fast-track the construction of the new 2-million-gallon North Elevated Storage Tank (NEST). EST is helping the City of Melissa make the new NEST a reality on schedule and under budge.

The City of Melissa’s vision for this project was that it would become a “signature” monument promoting the community, as well as serve as a central structure for a municipal complex with several floors and usable interior space. Additional design features included fire sprinklers, heightened security, outdoor lighting, and sanitary sewer service in the tower. Operationally, the City wanted to be able to reverse the water flow direction from the distribution system back into the water tower, as needed.

The tower is fed by chloraminated water purchased from the Greater Texoma Utility Authority (GTUA). The GTUA requires an air gap between the two systems, eliminating all bypass pumping options. Since the water is purchased, the Texas Commission on Environmental Quality (TCEQ) requires on-site chloramine boosting, chloramine monitoring, and tank mixing. Chloramine chemical delivery and storage is provided in the tank pedestal.

To predict the influence of the water tower on the distribution system, EST revised the City’s existing water model to an extended period duration simulation to verify the performance of the current distribution system. EST then added the proposed elevated storage tank and performed an extended period simulation to confirm the tank size and overflow elevation to achieve the desired impacts.

EST designed the new 2-million-gallon pedestal-style North Elevated Storage Tank with aesthetic and functional qualities in mind. As a composite tower it has an impressive appearance with lower life-cycle costs for operation and maintenance. The NEST’s concrete pedestal includes three interior floors, with the top two for storage and a multi-use bottom floor housing the chloramination system – complete with HVAC, spill protection, negative pressure venting, and fire suppression systems. To allow maximum operational flexibility, the NEST was designed with separate inflow and outlet pipes capable of reversing and measuring flow from the distribution system back into the water tank. Due to the required air gap, the chloramination system was integrated with a mixing system that allows the chloramine booster to inject directly into tank to ensure water quality. This design feature simplified the chloramination system with the added benefit of tank mixing, allowing the system to accept water with different levels of chloramination.

EST completed the civil design, tower design, process piping and chloramination system/process design. EST coordinated the electrical, mechanical, civil, mixing system, and fire protection engineers to author the engineering report, design specifications, and complete permitting the project with TCEQ. After the project was permitted, EST helped the City of Melissa during the bidding and award process. Landmark was selected as the tank provider, and EST is continuing construction management and coordination.

EST provided construction drawings and cost estimates, and construction administration, inspection, and testing services for the new City operations facility, providing drives and utility design and for the new development.

The EST team performed – Services Provided: