Broken Arrow mulling wastewater options, potential new treatment plant

By John Dobberstein, Editor

Broken Arrow city officials are moving to address sewer capacity issues in the Adams Creek sub-basin, and building a new wastewater treatment plant on the northeast side is a potential option.

The Broken Arrow Municipal Authority (BAMA) recently gave its blessing city engineers to seek proposals from firms to do a feasibility study for such a plant, and to identify other potential alternatives. The study could take 6-12 months.

City planners know time is of the essence, as more residential growth is expected on the east side of Broken Arrow in the coming years. In the next decade alone, at least 2,000 residential lots with 8,000 individuals are projected to be developed in the Adams Creek sewershed.

Currently, treated wastewater goes into the Arkansas River, but if a new plant comes online that flow would be released into the Verdigris River. The city would then be able to eliminate 12 lift stations that are costly to operate and maintain.

A feasibility study would look at the potential costs of either building a treatment plant in the basin or making other collection system improvements to address the capacity issues. The potential site and treatment requirements and expected development would also be studied.

Building a new treatment plant would let the city to convert 12 lift stations to gravity sewer, and existing capacity at the Lynn Lane Wastewater Treatment Plant would have adequate capacity into the future. This option would also greatly reduce sanitary sewer overflows, the city says.

The city would incur a cost for buying the land, staffing the new plant, improving the collection system to convey flow and paying for a plant’s operational and maintenance costs. Design and construction of a new plant and system modifications could take 6 years or more.

Decades of growth

The city has been grappling with growing pains ever since the Broken Arrow Expressway opened in the 1960s. City limits in 1990 were nearly 40 miles with a population of 58,481, but in 2020 the population was estimated at 110,000 spread out over 62 square miles.

This represents an 88% increase in population and 57% increase in square mileage over that time period.

The BAMA collection system consists of two major basins in 63 square miles. There are 695 miles of gravity sewer lines, 25 miles of force main, 16,220 manholes and 30 lift stations.

There are 22 sub-basins in the Haikey Creek Wasterwater Treatment Plant area and 20 for the Lynn Lane Wastewater Treatment Plant area, which includes the Adams Creek sub-basin. The sanitary sewer flows from this sub-basin to the Lynn Lane Wastewater Treatment Plant.

The Haikey Creek Wastewater Treatment Plant is operated by the Regional Metropolitan Utility Authority, which encompasses several cities in the Tulsa metropolitan area, including Broken Arrow.

Throughout the planning process for Lynn Lane plant upgrades, as well as collection system upgrades, the Adams Creek sub-basin has been examined more in depth of late, and led to discussions among city planners about the best way to handle the flow from this sub-basin — which naturally drains in the opposite direction of Lynn Lane WWTP.

The Adams Creek basin is approximately 20 square miles, which takes up a third of the city’s overall sewershed area. It’s made up of about 12 lift stations, four of which pump wastewater over the ridge to County Line trunk sewer.

This type of operation setup requires significant maintenance and often cause sewer lines/manholes to degrade more quickly, says Ethan Edwards, the city’s director of engineering and construction.

Lift station rehabilitation and mandatory expansion have been happening in the Adams Creek area to handle existing flows. Lynn Lane plant rehab and expansion projects have also been done to handle flows into the plant.

The city’s wastewater master plan, completed in 2018 by the civil consulting firm HDR, evalauted the capacity of the city’s existing wastewater collection system and the condition of the two plants it. uses, the existing sewersheds, current and future system loading and provided a capital improvement plan.

The master plan laid out three scenarios for handling the flow issues in Adams Creek

• Maintain the existing Lynn Lane and Haikey Creek sewersheds.

• Expand the Lynn Lane plant sewershed and reduce flow to the Haikey Creek plant.

• Reduce the Lynn Lane plant sewershed and send flow north to a new treatment plant.

Managing the cost

City Manager Michael Spurgeon says he expects recommendations from the wastewater study will be expensive and the city will have to evaluate each option and the financial impact.

Stormwater improvements in Adams Creek are another issue that will need to be dealt with in the future, he said, as residents are getting concerned on development happening in the area and its potential impact.

“Do we want to save capacity on our rates and look at making it a part of a bond package, such as a proposition for water and sewer improvements? Or do we want to go ahead and put it on the rate payers — which would take onger vs. a general obligation bond?” he said. “If we get this study don’t we’d be in a better position to evaluate the best way to pay for improvements.”

At-large city council member Johnnie Parks says determining the plant location in the next year or tow is crucial, as current and prospective homeowners have right to know where a potential plant will be. He notes the Lynn Lane wastewater plant was built far away from the city to address odor issues, but developers still built homes right up next to it.

Overflows troublesome

Sewage overflows have become a problem for the city in the last several years, especially in the Adams Creek area.

In 2019, DEQ notified BAMA and the city that it violated Oklahoma statutes prohibiting pollutant discharge into state waters. A pump at the Adams Creek lift station was overwhelmed with water and malfunctioned during heavy thunderstorms, resulting in raw sewage leaking into Adams Creek.

The notice of violation turned into a DEQ consent order which requires the city to fix some of the capacity issues and get back into compliance by April 2025. In 2017 the city council was cited by the DEQ due to a sewage overflow that happened near County Line Road due to a sewer line break.

The city says it’s on track to meet timelines that staff negotiated with the DEQ for the consent order, and that number of public works projects have been completed or are ongoing in the Adams Creek area to mitigate the issues.