A rupture in the main line, which carries a large percentage of the county’s sewage, resulted in an unauthorized discharge into the Lake Catherine watershed on Thursday.
The break was downstream of the Gulpha Creek pumping station on Catherine Heights Road. Hot Springs Utilities director Monty Ledbetter said Friday the pumping station had to be taken out of service while the failed main section was replaced.
This caused the flow from the 30 inch diameter gravity line to back up upstream of the pumping station and exit the shaft adjacent to Gulpha Creek. According to Ledbetter, the pumping station was shut down Thursday morning and restarted in the afternoon. Sewage continued to flow out of the manhole until the pumping station cleared the flow that had backed up in the gravity line.
Video not playing? Click here https://www.youtube.com/embed/aQAftre0BLg
Ledbetter estimated that about half of the regional sewage system’s flow flows through the pumping station, which is located at the lowest point of the Gulpha Creek Basin collection area. It collects wastewater from downtown Hot Springs and areas north and east of the city.
“We shut down the pumping station and it spills over into the Spencer Bay area when we do that,” Ledbetter said. “Then we’ll do the repair and get it running again. It takes several hours to pump down the system again. It usually takes about 10 hours for everything to go back to normal. We fixed it just after lunch yesterday. It takes a while for it to pump out and catch up.
He said materials for major repairs are kept in the Adam Street Supply Department. Catherine Heights was closed during the major Shady Heights to Fernwood exchange.
“We have pipes and clamps to fix these things,” he said. “We have a little bit of everything here on Adams Street where we can do any type of repair to our water or sewage systems.”
The pumping station pressurizes a 20-inch line that the city has agreed to replace under the government mandate it has been under since 2008. Ledbetter said the city hopes to bid on the project soon and have a contract awarded by late spring.
“It’s a 50-year-old ductile iron pipe that sewage has been pumped through all these years,” he said. “It blows out in an area that’s exposed to higher pressures because of the altitude. Once it’s blown out we have to shut down the pumping station because that’s the only main line we have.”
The city has reported millions of gallons of illicit discharges from the well adjacent to Gulpha Creek, including more than 5 million gallons in the first half of last year and 1.38 million gallons in mid-December. Eighty percent of the overflow volume in the Gulpha Creek basin flows from the well, according to information presented last week at a meeting between the city and its utility advisers and officials from the state Department of Environmental Quality.
Ledbetter said a 30-inch power line will replace the 20-inch line. The modernization of the pumping station is also scheduled to begin in late spring. He said improvements to the gravity line upstream of the pumping station are due to begin next year.
“(The 30-inch line) will have extra capacity to handle rain events, and the pumping station will also be rated for that, Ledbetter said. “The pumps will be able to handle the larger flow rates. We can handle a pretty big event with that.”
The city struck new deals with DEQ early last year after the agency refused to release it from its 2008 mandate. The new mandates require the city to test stream samples within 12 hours of an overflow and provide DEQ with water quality assessments.
Improvements that will increase the peak flow capacity of the Davidson Drive plant from 20 million gallons per day to 48 million must be completed by the end of next year. Peak runoff occurs during stretches of sustained rain when runoff enters the collection system and enters the facility.
Biological processes that break down wastewater must be bypassed. Tertiary fabric filters, which came on stream early last year, can remove contaminants from the flow that has bypassed biological processes and provide another layer of treatment before the effluent undergoes UV treatment en route to the city’s authorized drain below Carpenter Dam. is subjected to disinfection.
The new agreements give the city a 2030 deadline to make improvements that fix any sewer system overflows. Under the amended mandates, the city reported 156 million gallons of spills from January 2018 through June 2021.
The new sewage fee structure introduced by the Hot Springs board of directors is a debt service issued for the improvements, increasing the monthly debt service fee from $17.73 to $19.73 for residents within the city. It will rise to $24.48 in January 2024, with annual increases of 3% projected for subsequent years.
The fee for out-of-town residents rose to $27.39 last January. It will rise to $34.05 in January 2024, with annual increases of 3% projected for subsequent years.