Continuous monitoring

Meeting the new expectations around continuous monitoring of combined sewer overflows presents an enormous challenge to the water industry, but Yorkshire Water is tackling it head on.

Lucinda Dann, features editor

Continuous monitoring

Meeting the new expectations around continuous monitoring of combined sewer overflows presents an enormous challenge to the water industry, but Yorkshire Water is tackling it head on.

Lucinda Dann, features editor

When new requirements around continuous sewer monitoring were unveiled some water company sources described them as “unviable”. Section 82 of the Environment Act 2021 mandates water quality monitoring up and downstream of every storm overflow and sewage treatment works in the country, with data needing to be collected up to every 15 minutes and published in near real-time.

The logistics needed to implement Section 82 have been branded “a nightmare”, with issues around site access and lack of signal being serious challenges for the industry to overcome. One industry figure warned that monitoring technology is not mature enough, meaning “water companies will spend an awful lot of money without achieving outcomes”.

The Independent Water Commission’s 2025 report also questioned the wisdom of pursuing the legislation, citing the huge cost, limited measurement parameters and lack of future adaptability as potential issues. It concluded that while a comprehensive monitoring regime was necessary, future water monitoring programmes should be reviewed and adequately resourced and that the current framework requirements for high granularity monitoring may be too resource-intensive.

736

Number of monitors to be installed in Yorkshire Water's networks by 2035

Despite these widespread concerns in the industry, one water company is powering ahead with meeting the demanding requirements, awarding the first contract of its kind under Section 82 in October last year. So far, the contract has delivered 22 of the 736 monitors Yorkshire Water needs to install over the five-year asset management period (AMP), and while the company is happy with progress, it acknowledges that gaining access to sites has been a significant challenge.

Getting ahead

Having recognised the likely delivery challenges associated with meeting Section 82, and fresh from a series of trials carried out in AMP7, Yorkshire Water was able make quick decisions about how it wanted to proceed at the start of AMP8, making it one of the first movers in this area, says Steven Jackson, its river health strategy manager.

“We did a series of innovation trials in AMP7 that helped us to understand how we wanted to approach the market, so we started procurement pretty quickly as we moved into AMP8. Our contract was ultimately awarded to Socotec following a full tender process, and that’s allowed us to get the ball rolling on the delivery,” says Jackson.

The contract, which lasts for more than six years, was worth more than £97 million when Yorkshire tendered for it in 2024.

Meeting the requirements of the Environment Act will require a lot of manpower from suppliers because in addition to site inspections and installation, each site needs to be recalibrated regularly. “Section 82 requires calibration of sensors every four weeks, which requires a visit. When you have the scale of sensors going into Yorkshire and also the wider water industry, that equates to a lot of people and a lot of time out in the field," says Jackson.

“That early decision to get out to market quickly gave us the opportunity to secure some capacity in the market, as there were initially some concerns about the ability of the supply chain to scale up to meet demand across the AMP period.”

Moving early allowed Yorkshire to opt for an established player in the market, which has also helped them to move forwards quickly with the rollout. James Teale, operations director, water quality division at Socotec, explains: "Having designed and manufactured the AquaHawk pump kiosk ourselves several years ago, we've already gone through the full testing process and built up real operational experience with the equipment. That head start allows us to move quickly and deliver with confidence, at a time when much of the market is still bringing new solutions up to speed.”

For the first five-year period of the rollout Yorkshire Water plans to install 736 monitors, around 25% of the total amount that will need to have been completed by 2035.

In Yorkshire Water’s Year One Control Deliverables Progress Report for AMP8, published in August this year, the company revealed that 22 monitors had been delivered by the programme in 2025/26, meaning it is on track to meet its targeted output by the end of the AMP.

“Our profile of rollout ramps up as we move through this AMP period, so we are starting relatively small and growing in years three, four and five in terms of scale of delivery, so it’s given us that opportunity to learn a little bit from the monitors that we first put in and then build over time,” says Jackson.


“Our profile of rollout ramps up as we move through this AMP period ... so it’s given us that opportunity to learn a little bit from the monitors that we first put in and then build over time.”

Steven Jackson, river health strategy manager, Yorkshire Water

Siting challenges

Despite having completed only a tiny fraction of the full number of installs required during this AMP period, Yorkshire Water has already encountered many of the logistical issues cited by the industry. The primary challenge has been around gaining access to sites. “The first ones we delivered last year were on our own land, where we didn’t need to work with third party landowners. These were the easier ones from a delivery perspective, as we had more control. Obviously as we move into future years, we don’t own all the land on riverbanks across Yorkshire, so we are now starting to build relationships with landowners for future installs,” says Jackson.

Due to focusing on sites under Yorkshire’s ownership, the cost has been much less than the £2.9 million anticipated in the first year of the programme, with a spend being just £682,000 because fewer surveys had to be carried out.

Under the new Section 82 guidelines, water companies must use pump kiosks as their primary deployment for water monitoring. These kiosks are relatively large green cabinets stationed on the banks of a river which pump water out of the river for testing every 15 minutes. Water companies are required to justify why a pump kiosk cannot be used at a site, with the alternative being an in-river solution. Teale says that while a kiosk has the benefit of being a secure solution and can be maintained by just one person, it is not suitable for every site.

“Moving water really long distances through sample hoses can have a slight detriment on data quality, and it also means the pump kiosk needs to use more power. That's why our site inspection experts review the conditions on each site and select the most appropriate equipment accordingly.

“These are all remote, battery-operated systems, so if local conditions limit how close a pumped kiosk might be sited, an in-river solution might be a better option," he says. “One of the main limitations is really steep banks, which can mean the equipment isn't always suitable - though in those cases, the banks aren't easily or safely accessible for people either. Access is a genuine challenge, which is why we send teams out to inspect the site and assess a range of options before identifying the best stretch of river and land for installation.”

While in-river solutions, which are sensors that sit directly in the river, overcome many problems, they also bring their own challenges, such as being more prone to being caught up in debris and requiring two people to calibrate them, which doubles the maintenance cost.

Another recurrent issue is trying to ensure the kiosk has a clear south-facing view for the solar panel that sits on top of the cabinet to power the testing. Seasonal changes, such as vegetation growth, are also presenting a problem.

Additionally, the team at Socotec have found the incredibly dry weather experienced by the country over the summer may require some installations to be moved.

An installation carried out in the winter months can find, by summer, that the river has dried up almost completely, leaving all the equipment in place with no river left to monitor. "In other cases, water levels drop so low that we need to relocate the sensors to reach the shallower parts. It's not a case of installing the equipment and leaving it - there's a significant amount of ongoing maintenance involved," says Teale.

While Socotec has not moved any sensors yet, it may need to lengthen some of the hoses that have already been installed.

The final siting challenge is third party acceptance, with Teale accepting that sometimes landowners “don’t want a cabinet installed on their land and want something more discreet”. While third parties can outright refuse to host monitoring equipment on their land, in which case Yorkshire Water has to find an alternative site up or downstream, which has happened in a number of cases, Socotec has also come up with some bespoke installation solutions to help with acceptance.

This is an “invisible solution”, which sits entirely underground in a manhole, Teale explains. He adds: “In addition, we've developed a Victorian lamppost design as a bespoke product for a site located within a Site of Special Scientific Interest, where the property owner requested that any logging device be designed to blend in with the existing architecture - in this case, matching the lampposts along the customer's driveway.”

In other cases, landowners are happy with the install but ask for the data to be shared.

The final element of Section 82 is a public platform to host all the monitoring data, which will become live by 2030. Jackson stresses that this requires a consistent industry-wide approach.

“There are a number of parameters that some customers may not be aware of and there can be large variability in rivers over time, seasonally, daily and depending on asset operation,” he says. “So, we need to make this clear to the public to identify what is normal from a river point of view.”

Regardless of how consumable the data is for customers, or whether an alternative approach to monitoring is decided upon in the future, the current push for river quality data can only be seen as a good thing.

“It’s great for the environment and our understanding of river health. It demonstrates with good quality data the impact a water company is having or not having on the environment,” says Jackson.

“Any information about the health of our rivers helps support longer-term investment decisions and helps us identify sources of pollution in a river that may be water company related, but equally may be from third-party sources, and allows us to understand other factors that influence water quality.”