JACKSON COUNTY
ELDORADO - A small town in southwestern Jackson County expects to spend approximately $1 million to overhaul its faulty wastewater collection and treatment systems that resulted in lawsuits and mandates from the state Department of Environmental Quality (DEQ) to correct multiple problems.
Eldorado remains under a DEQ consent order that was issued almost 10 years ago but is gradually making progress in upgrading its sanitary sewer system.
In late 2000 Eldorado proposed to construct a new total-retention sewage lagoon treatment system to replace its aged lagoons, and to expand its wastewater collection lines, records show.
The DEQ approved plans for the project and in May 2003 issued a permit allowing Eldorado to construct a pair of 5-acre primary total-retention lagoons and a pair of 5-acre secondary evaporation lagoon cells; all four had a design operating depth of 4 feet.
GYPSUM-RELATED SINKHOLES
In October 2003 the DEQ expressed concerns about gypsum nodules “that were revealed during the subsurface exploration of the new lagoon site…” The agency’s letter pointed to the history of gypsum-related sinkholes in areas of Jackson County and advised town officials that “care should be taken to prevent excessive seepage” which could lead to sinkholes at the new sewage lagoon site.
The DEQ suggested some options to consider, such as clay liners, synthetic liners, site relocation or bentonite seals. Bentonite is a clay-based material that is used as a sealant for ponds, municipal landfills, and sewage lagoons.
Representatives from the town and from the state agency met at the newly constructed facility on May 24, 2005, for a final inspection.
Exactly four weeks later, a DEQ environmental specialist was informed by an inspector from the project’s engineering firm, which designed and oversaw the construction of the wastewater treatment facility, that a sinkhole had appeared in lagoon cell No. 3 after “a significant rain event.”
The sinkhole was “in excess of 5 feet in diameter and at least 10 feet in depth,” the DEQ reported. Fortunately, the lagoon cell was empty.
According to DEQ documents, examination of the wastewater treatment site by the DEQ disclosed extensive presence of gypsum; evidence that a bentonite seal was used for the primary lagoon cell but native soils were used for the three other cells; evidence that the lagoon seals were not 12 inches thick as required; and an admission by a town official that a sinkhole had formed in a road approximately one-half mile northwest of the wastewater treatment lagoons.
In 2008 the DEQ concluded that Eldorado’s new wastewater treatment site was “unsuitable for operation of a lagoon system” and could not be rehabilitated “due to the high risk of the reoccurrence of sinkholes throughout the area.”
Eventually, a new location was secured, a new wastewater treatment facility was constructed, and the old lagoon site was closed. However, the DEQ discovered that while the lagoons passed muster, some of the new wastewater collection lines “did not meet minimum slope requirements” and therefore new lines had to be reinstalled.
LAWSUITS FILED
Meanwhile, Eldorado filed suit against at least two contractors and the litigation dragged on for more than a decade before it was settled last year, in the town’s favor, City Clerk Janice Miller said. One of those contractors has since gone out of business, she said.
The lagoon project cost approximately $800,000, Ms. Miller said and was completed by Nov. 1, 2013, DEQ records reflect. The new lagoons were financed “mainly by grants and proceeds from the lawsuit settlement,” she said.
Eldorado received funds from the Indian Health Service (an agency within the U.S. Department of Health and Human Services) and a community development block grant, Ms. Miller said.
Now the town expects to spend an estimated $382,266 to finance repairs to the sewage collection system.
The Eldorado Public Works Authority recently received a $150,000 Rural Economic Action Plan (REAP) grant from the Oklahoma Water Resources Board (OWRB), which will be coupled with $232,266 in local funds on hand resulting from the civil litigation.
Project blueprints call for replacement of 45 manholes and approximately 12,200 linear feet (2.3 miles) of 8-inch-diameter sewer lines in various locations throughout the town, to eliminate sewage overflows.
The project also will include the restoration of 70 customer service connections, OWRB records show.
The five-member Eldorado City Council is expected to advertise soon for competitive bids on that project.
BIDS
“Through the enforcement process, Eldorado has completed upgrades to the treatment side of its system,” said Erin Hatfield, the DEQ’s communications director. “The remaining work is to complete collection system upgrades to address infiltration issues.”
Eldorado has a population of approximately 400 and about 200 utility customers who pay $13 per month for basic sewer service, Ms. Miller said.
The city’s water customers pay $15 per month for the first 2,000 gallons, $28.41 per month for 5,000 gallons, records indicate. The Eldorado PWA buys treated drinking water from the Harmon Water Corp. in Gould and from CRETA Water Corp. based in Hollis.
The town’s trustees are holding the line on utility rate hikes, Ms. Miller said, “because a lot of our residents are elderly and on fixed incomes.”