Planning is Key to a Smooth Water Storage Tank Rehab
Maybe a water tank looms large above your town, performing a vital, if not somewhat obscure, role. Clues to its history and upkeep may be sparse, uncertain, or nonexistent as these structures get little attention outside of every 25-30 years when it’s time for rehabilitation. The unknown can be intimidating and figuring out where to start can be overwhelming. But with a good roadmap to guide you through the process, you’ll be able to rehab that giant structure in an efficient and low-stress manner while minimizing interruptions to water service to your community.
Any tank rehabilitation project must start with a solid understanding of the current state of the structure and how its rehabilitation will impact its surroundings and the overall water distribution system. An overall inspection of the tank, inside and out, is the starting point for getting a close-up look and hands-on documentation of existing conditions. This will provide direction for a prioritized approach and setting an appropriate budget and schedule. For example, can you enhance the tank’s exterior with only a fresh coat of paint or are there other repairs demanding attention, like in this rehab project for the City of Huron?
Following these steps and considerations can help your rehab project get off to the right start.
Perform a “hands-on” inspection.
An inspection will help determine if the repairs are typical or unique and allow you to assess the condition and composition of the existing coating system. During inspections, the thickness and adhesion of the coating should be tested, and it should be determined if there are environmental concerns for disposing of the coating.
Assess the surface and select the new coating.
First, identify the surfaces that need a new coating – exterior, wet interior, or dry interior? Depending on which surfaces need a new coating, you can determine if a complete removal of the existing coating is required and if the new coating will need an overcoat, gloss, and color retention. This step also can be used as an opportunity to consider the aesthetics of the tank and decide if a new logo design is needed and what the sizing requirements are.
Determine if any additional coordination is required with outside entities.
If any local communications, cellular, or FAA lighting equipment is already installed on the tank, be sure to coordinate with each respective entity to ensure continued service and a smooth transition during the rehabilitation.
Assess the tank site and accessibility.
Identify any safety or security upgrades that need to be completed. Evaluate the tank’s proximity to structures and other properties and if there is adequate overflow and site drainage.
Determine if the tank needs mixing systems to improve water quality.
Taking a tank out of service for rehabilitation is an ideal time to consider the need for a tank mixing/aeration system to address factors such as stratification and EPA regulatory thresholds (THMs), which can negatively impact water quality.
Consider service interruptions.
Use hydraulic modeling to determine impacts to the distribution system and be able to answer questions like how long the tank will be out of service.
Establish the repair budget and lifecycle goals.
Define the goals for the tank and its lifecycle. Based on the goals and the findings from the steps above, you can establish a sound repair budget that meets your needs.
Once the inspection is completed, proceed with selecting and designing the improvements best suited for your tank’s specific needs. Starting with the big picture enables a logical sequencing of the required tasks. Then, your concern will no longer be how to start, but when.
Tim Antos, PE Director, Painesville Utility Infrastructure Section