Stokes Creek pump station overflows again during heavy rainfall

The Stokes Creek pump station not being fully operational led to the latest wet-weather overflow reported there since February, the city said Tuesday.

Deputy City Manager Bill Burrough said the overflow occurred from 1 a.m. to 4:30 a.m. Saturday at the manhole where a 28-inch gravity main turns 90 degrees toward the pump station, which was upgraded as part of the $70 million, ratepayer-financed overhaul of the city's regional sanitary sewer system.

District 4 Justice of the Peace Jimmy Young, who owns the RV Park next to the pump station at the McLeod Street-Lakeshore Drive intersection, filed a complaint with the Arkansas Department of Environmental Quality. Burrough said ADEQ subsequently notified the city Monday.

Stokes Creek empties into Lake Hamilton.

"ADEQ did receive the complaint," agency spokeswoman Kelly Robinson said. "At this time, the Office of Water Quality enforcement branch is working with the city of Hot Springs regarding remediation."

Burrough said only two of the pump station's three pumps are in place. He said flow can be directed downstream, even during a rain event like last weekend's, without incident once the full complement of pumps is operating. Hot Springs Memorial Field, which is just north of the pump station, reported 1.92 inches of rain Friday and a 0.74-inch total Saturday.

"We haven't signed off on the pump station yet," he said, noting that the third pump should be arriving within a month. "There's still some punchlist items that need to be completed. Once we get the third pump set up, it should be able to keep up with the flows."

Burrough said he suspects the natural gas-powered backup pump that contributed to the February overflow also played a role in last weekend's incident. The city's response letter to the earlier overflow said a programming error prevented the backup system from operating at full capacity.

"It's still a new machine," he said. "I think what happened is the programming of the (backup pump) is not letting it run fully to empty the wet well. When the wet well gets full, the flow has no place to go. We had so much flow that the two pumps couldn't keep up with it."

Burrough said the pump station will alert the city to overflows once it's fully operational, allowing the city to respond faster than it did to Saturday's event.

"That concern should be rectified once we finish the rest of the pump station," he said. "We always go out and clean the area and treat the area. That didn't happen until Monday when we were notified there was an overflow. The complainant will call Entergy, the newspaper and ADEQ but doesn't call the city. So in this particular event we didn't realize we had an overflow."

The complaint Young submitted to ADEQ concerning the February overflow coincided with 9.82 inches of rain recorded at the airport over four days, with 4.26 inches reported during the second day of a rain event the city characterized as a 10-year flood that would overwhelm most collection systems.

The rainfall caused the 54 million-gallon equalization basin at the regional wastewater treatment plant on Davidson Drive to reach maximum capacity Feb. 23, leading to an unpermitted discharge the city reported to ADEQ. The basin was holding flow while the plant's new headworks was under construction.

A bypass pump directed flow around the construction to areas further downstream in the treatment process, with the city bringing in an additional pump to accommodate the extra volume. The discharge lasted four hours, according to the city's letter to ADEQ.

"Plant staff cleaned up the area of the unpermitted discharge consistent with the city of Hot Springs sanitary sewer overflow cleanup plan," the letter said.

The formal request the city submitted in November for release from the consent administrative order it entered into with ADEQ in 2008 said more than $6.2 million has been spent rehabbing 4,215 manholes and replacing another 199. The improvements have kept almost six million gallons of groundwater out of the collection system during a one-year rain event.

The request said the city reported three overflows over 416 miles of pipe from November 2016 to November 2017. It noted $5.9 million in improvements to the 28-inch gravity main that parallels McLeod Street and carries flow to the Stokes Creek pump station, improvements Burrough said have performed well during a wet winter and spring.

"The mains running down McLeod, those were chronically overflowing," Burrough said. "We'd have an overflow with almost any rain event. With the work we've completed with the CAO, we haven't had overflows in any of those lines."

No overflow complaints have been filed for the manhole near 2325 Lakeshore Drive since May. It's been the subject of numerous complaints since 2012 but was addressed as part of the $70 million revamping of the system.

The city entered into the CAO after 359 wet-weather overflows were documented from January 2004 to May 2008. It paid a $105,000 voluntary civil penalty in June 2011 as part of the order.

Local on 04/18/2018

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