PRESSURE ZONES & AGING INFRASTRUCTURE
When we think of addressing aging infrastructure problems it is usually a project to repair or replace that comes to mind. At times, other solutions may be possible that achieve the desired result with less expenditure of funds. Analyzing the interworking of a system that has had years of use and years of modification may allow for plans to be created which highlight the most efficient way of dealing with these problems. The town of Redmond did just that.
Mayor Paul Christensen and Water Superintendent Rick Mickelsen combatted their town's aging infrastructure head-on. They outlined problems with two different pressure zones, a faulty pressure sustaining valve/reducing valve, and two aging 100,000-gallon concrete water storage tanks.
The pressure sustaining valve was a concern due to the risk of it failing. If it failed the two lower water tanks would overflow, resulting in flooding down the hillside. Hillside flooding would damage the tank area and possible nearby residential areas. The concrete surrounding the tanks had started to crumble and erode. The tank lids had developed large cracks.
As major infrastructure problems start to present themselves, it can be easy to become overwhelmed. The town officials saw these problem areas and knew it was time to act. They reached out for support to Utah Rural Water Association’s Southern Circuit Rider, Greg Johnson. The first step is data collection. Collecting an adequate amount of appropriate data allows systems and municipalities to make the best plan of action. They pulled the maps of all four water storage tanks and studied the elevations, the population on the town water system, and the requirement of water storage mandated by the Utah Division of Drinking Water.
The upper water storage tanks were approximately 60 feet higher in elevation. Greg did the math and assured Paul and Rick that by bypassing the pressure valves that the pressure increase would be minimal, around 15 psi (pounds per square inch), and that the public probably wouldn’t notice a difference. At the time, the town’s current water storage was 850,000 gallons. The calculations provided the assumption they could take two 100,000 gallon storage tanks out of service and still be in compliance. This would also allow the town to still meet the fire flow high peak demand of 650,000-gallon storage.
It was concluded that a pressure test was needed. We needed to determine how the water pressure would change when the faulty valves were bypassed and how that would affect the pressure in older residential areas. If the pressure was too high, it could seriously damage the plumbing in older homes. The pressure test was scheduled for when it was most likely that people would be at home so that homeowners would notice if their plumbing would be affected. The town notified customers about the test, so they would be observant of any changes.
Paul, Rick, and Greg went around town and took static pressure readings on the day of the test. At 6:00 p.m. they opened up the pressure stations and tested the same locations that were tested earlier to compare pressure. There was an 18 psi increase from before. They left it that way for 5 hours and had no complaints. In fact, the public was very pleased with the results. Several residents notified town officials that the water pressure had improved. They put the pressure stations back into service until they could re-route the water main lines around the old water tanks and pressure stations. The result? The maintenance headaches and worries were gone along with the flooding issues. The money saved by repairing or replacing the old water tanks made everything worth it.