City staff overcomes Polar Vortex of '21
Last week’s siege of cold weather and power outages was one for the history books.
According to the Texas Commission on Environmental Quality, “As of 10:45 a.m. Saturday, February 20, 1,445 public water systems have reported disruptions in service due to the weather, many of them leading to Boil Water Notices. This is affecting nearly 14.4 million Texans in 190 counties.”
Additionally, millions of Texans went without electricity.
Amidst the crisis, city staff overcame multiple obstacles to keep water flowing to our customers.
Prior to the arrival of the polar vortex, staff reviewed the city’s state of readiness. All of the outdoor lines at the city’s five well sites were insulated. Heat tape had been installed under the insulation on the smaller lines, which are more vulnerable to freezing. Electric heaters were installed in all of the water system’s buildings.
The water system’s SCADA system, which allows staff to monitor all the water wells, transfer pumps and storage tank levels from a smartphone or over the internet from a computer, was fully functional.
The city’s portable generators were ready to go. Faucets were dripping, and city facility water lines most vulnerable to freezing were turned off.
All was well — until the not-so-rolling blackouts began on Monday, Feb. 15.
We had been warned there would be rolling blackouts, but no one said anything about power outages, which would go on for three or four days.
At this time of the year, all of the city’s water comes from Somervell County Water District, so there wasn’t any need to worry about the wells that were without power. However, there was cause to worry about the non-operational transfer pumps that push SCWD water up into the city’s elevated storage units that provide pressurized water to our customers.
To keep providing water to the eastern-most portions of town, staff hauled a 10,000-plus-pound generator to the water facility near The Promise. It proved to be a major challenge getting the heavy generator up that first icy hill on Texas Drive. A backhoe had to be sent to the rescue. By night-fall, the generator had been connected and the transfer pumps were working.
The next challenge arose when an old water main, which wasn’t on our plans and for which there weren’t any shut off valves, developed a leak. Some of our staff worked all through the night on Monday to fix the leak. In the early hours of Tuesday morning, with temperatures near zero, staff borrowed a wet suit from the fire department to be able to get into the water and install a clamp to fix the leak.
With the prolonged power outage and extreme cold, infrastructure began to freeze. Sensors quit working. Staff couldn’t determine the water level in our tanks, except through a visual inspection through a hatch on top. Getting to the hatches on our 24-foot tall ground storage tanks wasn’t a problem, but in the frigid cold, management didn’t want to put staff at risk climbing the icy rungs on our 100-foot tall elevated storage units. We knew the units were low, but we weren’t sure exactly how low. Staff also lost the ability to monitor the various system components via smart phones and the internet. For a while, we were flying blind.
The aforementioned leak, in conjunction with all the customers in the city and in SCWD who were dripping faucets, put a major strain on the district’s ability to keep up with demand. For a while, they had to reduce the amount of water being delivered to the city’s system. This wouldn’t have been so bad, except that by that point all of the wells had frozen and two of them were without electricity. To make matters worse, we began having trouble with some of our transfer pumps. One of them burned-up.
On Tuesday, staff called in a pump expert to deal with the transfer pump problem. Although not all its sensors were working, the SCADA system was brought back on line. Staff began working to thaw out the lines at the Paluxy Summit well. By about an hour after sunset, that well was up and running.
On Wednesday, staff worked on reading meters and thawing out the well on Highway 56 north. Once the meter readings had been collected and uploaded into the system, a list of flagged “high usage” accounts was generated. With a view to reducing stress on the system, office staff immediately notified customers on the list who appeared to have leaks.
A little after dark, just as the field crew was about to finish bringing the Highway 56 well into service, a valve that was being turned off on Highway 67 broke. Although this repair job wasn’t nearly as difficult as the one from earlier in the week, it was another late night for staff.
When other valves were closed to enable the repair of the broken valve, water pressure dropped in unexpected areas in the system due to the lower than normal levels in the elevated storage tanks. This incident prompted staff to issue a boil water notice on Friday.
Various conditions can trigger a boiled water notice, with one being when system pressure falls below 20 pounds. At that point, regulatory authorities are concerned that contaminants might enter the system. As a precautionary matter, boil water notices are issued until the pressure has been restored and a water sample from the system, when tested by an approved lab, is found to be free of contaminants.
On Saturday, favorable test results were received and the notice was lifted.