The morning of Saturday, July 3rd our lead well, Well #1, suffered a partial failure causing a reduction in its capacity that resulted in Well #3 kicking in to satisfy demand. Well #3 is currently over the maximum contaminant level (MCL) for uranium, and while it hasn’t been cited by the State, the Board of Directors gave direction at the beginning of this year to our Water Company Manager to minimize the use of Well #3 out of an abundance of concern for health and safety.
The basic synopsis is that due to the reduced capacity of Well #1 Saturday morning (approximately ~400 gpm versus 1000 gpm) Well #3 kicked in until it was manually turned off after the wells were checked that morning by Staff. It is estimated that Well #3 pumped approximately 350 gallons per minute (gpm) for 3 hours.
The “on” pressure for Well #3 was set at 44 psi (versus our usual operating pressure of 52+ psi) to ensure Well #3 was in a lag lag position behind Well #1 and the Lukins Brothers Water Company (LBWC) inter-tie. It was assumed that the inter-tie was set to come on at 50 psi.
What went wrong on Saturday was that the LBWC inter-tie was actually set to come on at 45 psi (only 1 psi above Well #3). So when Well #1 started to fail, Well #3 kicked in rather than the LBWC inter-tie. The misconfiguration of the inter-tie came to light later that afternoon after discussions with LBWC and after their engineer physically checked the setting.
The other issue was that Well #3 had no “off” pressure switch as it was removed during the installation of the uranium treatment, so when it came on it kept pumping regardless along with Well #1 until manually turned off.
As of that Saturday afternoon, the LBWC inter-tie was reconfigured correctly at 50 psi, Well #3 was reduced to 40 psi and STPUD inter-tie was opened (as an emergency backup, given Well #1 was compromised). Since then, Well #3 has not been used and the LBWC inter-tie has been used intermittently (on Sunday Well #1 was magically back up to pumping 750 gpm).
The issue with Well #1 was that the gearbox had started to fail. Our staff had noted that the noise level of the gearbox had been increasing over time and we had decided to try and replace it with the new gearbox we had on hand as a backup. Unfortunately, this partial failure happened before we could get this done.
On July 15th we were able to take Well #1 offline for the day to replace the gearbox. During this time the LBWC inter-tie was able to supply enough water that we didn’t need to use Well #3.