Nov 09 2018

MUB places additional CSO signage along river and Deckers Creek

Signs designate Combined Sewer Outflow areas

Morgantown Utility Board crews have completed installation of additional signs along Deckers Creek and the Monongahela River. The signs warn of areas possibly impacted by Combined Sewer Outflows (CSOs).

CSOs are points permitted by the Department of Environmental Protection (DEP), where the sanitary and stormwater systems combine and occasionally discharge. During dry weather the CSOs have no impact on our local waterways. However, during significant wet weather events when the capacity of the system is exceeded, CSOs are designed to discharge excess flows directly to nearby streams, rivers, or other water bodies. During such discharges, the baseline flow (set by the conveyance capacity of the pipeline) continues to flow to the wastewater plant for treatment.

CSO discharges may contain stormwater and untreated human and animal waste, toxic materials and debris. Deckers Creek has 22 CSOs located along its banks and the Monongahela River has 16. One CSO is located along Popenoe Run near Brewer St, with another being at the entrance to the wastewater plant.

According to MUB General Manager Tim Ball, understanding CSOs requires understanding the history of sewer system development.

“CSOs are part of a legacy system and are common in systems such as ours. Prior to the construction of our wastewater treatment plant in Star City in 1965, all sewage was sent to the river or local creeks untreated. There was no separation between the sewer and stormwater lines,” he said.

As the system was developed in 1965, CSOs were necessary given the limited capacity of the wastewater treatment plant and pipelines.

“Because constructing a plant large enough to manage all stormwater flows and sanitary flows was prohibitively expensive, the CSOs discharges were utilized. Remember, before that time untreated sewage was discharged so the use of CSOs was not a concern,” Ball said.

Which brings us to the current upgrade of the wastewater treatment plant.

“The upgrade will increase the capacity of the wastewater treatment plant from 12 million gallons a day to almost 21 million. This increase in capacity will significantly reduce CSO discharges,” Ball added.

While MUB would love to eliminate CSOs from the local system, doing so is not financially realistic.

“We estimate the cost of eliminating CSOs themselves would easily run into the hundreds of millions of dollars. Of course, this would require borrowing money which would increase sewer rates incomprehensibly. Because of this, we are approaching CSOs from other perspectives,” Ball said.

This primarily involves increasing system capacity. The wastewater treatment plant upgrade is one example. Another is the replacement of the Popenoe Run Interceptor.

“We targeted the Popenoe Run Interceptor because, being constructed in the 1930s, it had reached its useable lifespan and needed replaced. In doing the work we not only located the conveyance pipe beneath the surface but added significant conveyance capacity to the system. This has reduced the discharge of that CSO from nine events in 2017 to a single instance in 2018,” he said.

Another example is a $17 million project that occurred around 2010. During this time the conveyance capacity of the sewer pipelines that run from the water treatment plant to the Star City wastewater treatment plant were upgraded. The expanded conveyance capacity had two immediate impacts. First, it reduced CSO output at the river front. Second, when the grit chamber at the Deckers Creek pump station is cleaned, untreated sewage is contained and conveyed to the wastewater treatment plant. Prior to this upgrade the untreated sewage was temporarily discharged to the river during the cleaning operations.

“Basically, because entirely eliminating CSOs is not feasible, we are approaching it from a capacity standpoint spread across multiple years. We are also looking at ways to electronically identify CSO discharges and share that information publicly. However, with everything, it’s a matter of affordability and functionality,” Ball said.

CSO discharge rates vary significantly by location. In 2018, some have not discharged at all while some have discharged as many as 65 times. CSOs are individually inspected each time it rains in accordance with specific rainfall thresholds.

A multi-year, quarter of a million dollar, comprehensive study on the effects of local CSOs upon water chemistry and aquatic life was conducted to assess the impacts of these wet weather discharges. These studies demonstrated that 72-hours following a significant wet weather event, there remained no impact of CSO discharge in local waterways. These results guided the preparation of MUB’s Long Term Control Plan for minimizing CSO discharges.

However, for Ball, CSOs are something that the public should understand. Hence the recent installation of new signs along the river and Deckers Creek.

“We received notice from the DEP that our current signage did not entirely fulfill the requirements of our NPDES permit. This prompted the installation of signs at public access points, and downstream of CSO outfalls, with additional messaging to alert the public to avoid contact with the water near or downstream of CSOs following significant rainfall events,” Ball said.

“Of course, we decided to go further than required by the NPDES permit and use this as an opportunity to begin a public conversation about CSOs. We were very much aware that installation of the signs in the manner and location in which they were placed would prompt public comment, which is something MUB always encourages,” Ball said.

Ball says that the best advice is to avoid the water for 72-hours following a rain event. He adds that, “The new signs don’t indicate that anything has changed. They are simply an improved message regarding the character of a system that has been in place for decades. And we are steadily improving that system with multi- million dollar upgrades that will continue to significantly reduce CSO discharges, thus contributing to an improved and enhanced waterfront.”

To aid in public awareness, MUB has developed a Google map listing CSO locations, with CSOs that most frequently discharge highlighted in red. The map can be found online here.. Also, while a list of CSOs and their discharges have always been publicly available, this information can now be found online at