City plans repairs to primary water reservoir
By Jon Hawley
Tuesday, January 29, 2019
It may cost $1.53 million to fix Elizabeth City's primary reservoir for untreated water, but city officials are hoping a state grant will cover that cost.
In an interview Wednesday, Public Utilities Director Amanda Boone said cleaning and maintenance continue on the city's primary reservoir for “raw,” or untreated, water. The reservoir can hold 3 million gallons, and it helps protect city residents from running out of water. If the city suddenly couldn't get water from its wells to water treatment plant, the city could draw from the reservoir to buy more time for fixing whatever the problem was, she explained.
That reservoir has also been out of commission since about August, when the city had to switch to using a much smaller, secondary reservoir. That's because routine testing in May found excessive levels of potentially harmful bacteria, triggering a “Level One Assessment” from state officials under the N.C. Department of Environmental Quality.
The main problem, Boone explained at the time, is that the primary raw water reservoir is uncovered, allowing animals and animal waste to enter it. The city's water treatment process makes the water safe to drink, but state officials want to see the tank covered to keep bacterial levels lower, she told the city council in July.
The secondary reservoir that the city's now using is covered, but it only holds 800,000 gallons, Boone said. That may sound like a lot, but the city's customers use about 1.8 million to 2.2 million gallons of water a day. Counting well-field reservoirs, the secondary reservoir and treated water storage, the city has storage to cover two days of usage, Boone estimated. Putting the primary raw water reservoir back in use would give an extra day's worth of supply, she added.
Boone said the city needs to replace the reservoir's liner as well as cover it. To do that will cost $1.53 million, based on an engineering estimate, she said. That's a lot of money, but it's also a big job. Just the “floating modular cover” the city is looking to buy would span about 22,000 square feet, based on numbers Boone provided. For comparison's sake, that's more than one-third the size of a football field.
To pay for the project, the city is applying to for a grant through DEQ's Division of Water Infrastructure; because the state has found the work is needed, Boone said she's hopeful the city will get funding. A decision is expected next month. If the city doesn’t get any funding, she would recommend the city pay for it in next year's budget. That would push back other improvements to the water system, but it would be necessary, she said.
In one benefit to the reservoir being empty and offline, city workers are cleaning it out, including removing some seven years' worth of sediment at the bottom, she also said. The well water entering the reservoir carries various particles that settle out or are removed during water treatment, she explained.
Once the “opportunistic maintenance” is done, Boone said the city will operate mud valves more often to reduce future buildup.