Image: Water tower
Introduction
Driving around town, I keep noticing these large cylinder-shaped water towers dotted around the Dallas area. These towers are elevated water storage tanks. Through my research about the water in Dallas, I learned that there are 21 storage tanks serving Dallas residents: 9 elevated, and 12 underground. These storage tanks are used to maintain water pressure, to store emergency water supply, and to provide additional water to meet peak demands.
Why are they cylindrical?
I’ve often wondered why all of these storage tanks are cylindrically shaped. Come to find out, there are a number of reasons for this. The cylindrical shape is better to hold liquid because it is extremely stable. The shape allows the storage tank to withstand the outward pressure that the liquid puts on the walls. It provides both a low center of gravity and strength to withstand harsher weather, especially high-speed winds as the cylinder allows wind to pass quickly around the tank versus pushing into it. The cylindrical shape, in the long run, also reduces corrosion and leakages that would occur in shapes with sharp edges and corners.
Sourced from: https://dallascityhall.com/departments/waterutilities/DCH%20Documents/pdf/ElevatedStorageTank_standards_Oct2012.pdf
Image: Side and top views of an elevated water storage tank.
What are some requirements of these storage tanks?
There are many requirements for how these storage tanks must be built. In fact, Dallas has a 30-page document outlining exactly what requirements these storage tanks must meet. For both elevated and underground tanks, there are, vehicular access, security access and surveillance, drainage, tank design, SCADA (control system), disinfection, quality assurance, warranty, acceptance, and administrative requirements. One of the most important requirements is the storage capacity and water pressure requirements: both elevated and underground tanks must meet the storage and firefighting demands (including hydrants and sprinkler systems) of the service area. One of the requirements is that the tank must be able to supply 500 gallons of water per minute to its fire hydrants.
Image: Fire hydrant in Dallas.
Conclusion
These storage tanks are the backup to the main water supply. Thanks to these storage tanks, Dallas was able to have running water through many storms that knocked out power in the Dallas area including: the winter storm of 2011, the winter storm of February 2021, the many tornados that occurred in the past few decades, and all of the smaller yet harsh storms.
I originally thought that these water storage tanks were merely eyesores—which probably explains why over half of Dallas’ water storage tanks are underground—but after learning more about them, I realize they are extremely valuable and clearly much needed
Image: Dallas in the midst of the February 2021 winter storm that knocked out power for almost 10 days.
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