Florida utility manages inflow and infiltration using flow monitoring devices and software tools from Badger Meter.
Emerald Coast Utilities Authority (ECUA) provides water, wastewater and sanitation services to Escambia County, Florida. The utility owns and operates three water reclamation facilities in the county, with a combined total treatment capacity of 33.1 MGD.
ECUA’s sanitary sewer network serves approximately 90,000 customers through nearly 900 miles of gravity mains and 300 miles of force mains. The utility also manages around 35,000 manholes and 400 lift stations. Much of the area’s infrastructure dates back to the late 1800s, with some of the original vitrified clay pipes still in operation today.
In recent years, high rainfall levels and ageing infrastructure have contributed to inflow and infiltration (I&I) issues and costly sanitary sewer overflow (SSO) events.
“Tracing rainfall inflow is very important for us because we’re in one of the three rainiest cities in the contiguous US,” said Mark Evan Robertson. “Because we have a high groundwater table, infiltration is fairly consistent. However, during a rainfall event, monitoring inflow helps us narrow down areas within the system that may be leaking and require investigation.”
To support I&I investigations through flow mapping and reporting, ECUA had previously outsourced lift station monitoring and control at an annual cost of approximately $320,000 for hardware rental and software licensing.
Typically, level sensors were installed for three to four months to gather operational data before being moved to another area of interest.
“When I joined ECUA, the utility was paying service fees every time a device was relocated, so many of the existing devices had remained in the same location since installation,” Robertson explained. “As a result, the data being collected was no longer particularly useful to the team.”
To reduce service costs and improve operational insight through more flexible deployment of monitoring equipment, ECUA partnered with Badger Meter to bring collection system monitoring in-house. Using open-channel flow monitoring devices, the utility aims to reduce rainfall inflow and prevent costly overflow events across the network.
Initial deployment
ECUA’s SCADA system provides lift station health data, including runtime reports and high-water alarms. This information is used to identify areas within the sewer network that may be experiencing leaks, enabling field crews to target inspection and rehabilitation work more effectively.
The initial installation included eight Raven Eye 2 flow meters with ultrasonic level sensors to improve operational visibility and monitor sewer levels to help prevent overflows and leaks.
The Raven Eye 2 is a non-contact radar area velocity flow meter designed to deliver accurate and reliable flow data for monitoring and I&I detection while reducing field maintenance requirements.
“A lot of our basins are very small, so pressure or area velocity meters positioned directly in the flow line are not always the best option,” Robertson said. “The Raven Eye 2 and RU-35 data logger can detect very small flow volumes, which makes them much more suitable for our operation.”
Several RG-32A rain gauge recorders were also installed at sites equipped with tipping bucket rain gauges. These wireless, battery-powered recorders are used to validate rainfall data alongside lift station data for greater operational insight.
Flow monitoring data is transmitted to Badger Meter’s Remote Monitoring software, enabling operators to view rainfall and site-specific data together within a single platform.
“Rain gauge data is used alongside lift station data,” Robertson added. “If there is a noticeable runtime difference between dry weather conditions and a rainfall event, this may indicate the need for further investigation by field staff.”
In larger trunk mains, ECUA is also deploying Beluga submersible area velocity flow meters. Both the Raven Eye 2 and Beluga devices operate alongside the RU-35 data logger to support open-channel flow monitoring, combined sewer overflow (CSO) and sanitary sewer overflow (SSO) monitoring, rainfall-derived inflow and infiltration (RDII) analysis, surcharge monitoring and custody transfer billing.
Putting the system to the test
During a recent four-inch rainfall event, five lift stations triggered high-water alarms. Robertson immediately deployed level monitors at these locations to track water rates over a period of approximately one month.
Traditionally, the utility would have carried out smoke testing to locate and repair leaks. However, by strategically positioning monitoring devices to isolate individual mains, ECUA was able to investigate several hundred feet of pipe rather than testing several miles of network.
“We don’t want to smoke test an entire basin because it simply isn’t cost-effective to have staff searching such a large area,” Robertson said. “Deploying these devices is like having another employee collecting data for us, allowing us to respond much more precisely.”
In one location, the utility identified between six and eight lateral breaks where water was entering the sewer network directly from a stormwater ditch, without the time and operational disruption associated with smoke testing an entire basin.
Developing a collection system action plan
As part of the utility’s Consent Decree requirements, ECUA is currently developing a collection system action plan to meet ongoing flow monitoring obligations.
“Part of our Consent Decree requirements includes pipe inspection, so these devices can help us meet those obligations,” Robertson said. “We can continue adding devices to the network and expand monitoring coverage across the system in future.”
Using trend reporting, operators can identify when readings fall outside normal operating ranges and prioritise investigation of areas experiencing the highest rates of change. This allows field teams to focus resources more effectively and reduce response times during I&I events.
“Ultimately, instead of simply monitoring levels, the goal is to resolve inflow issues altogether, monitor system performance and quickly identify any new inflow problems if they arise,” Robertson said.
Next steps
With the monitoring equipment now in place, Robertson is working to trace rainfall inflow data within a neighbourhood previously identified for sewer rehabilitation. The utility plans to compare pre-rehabilitation and post-rehabilitation data sets to evaluate the effectiveness of the upgrades.
Using open-channel flow monitoring technologies from Badger Meter, ECUA is progressing towards reducing rainfall inflow incidents and preventing sanitary sewer overflows across its wastewater network.
All images courtesy of Badger Meter.
