Smart Water Positioners

Positioners are critical to District Metered Areas (DMA) and a long-term investment that pay dividends.

Addressing valves left open or closed. 

Scenario. The flow rate and pressure within a District Metered Area (DMA) has dropped unexpectedly. Customers are reporting a leak. A repair team is dispatched to fix the problem. Following the isolation of the leak, consideration is given to ensure customers within the DMA continue to receive a water supply, but also to reduce the impact on adjacent DMAs, such as a loss of pressure and/or discolouration. A specific sequence of boundary gate valves are switched from open to closed or vice versa. The repairs are carried out successfully and the team leaves the DMA – neglecting to switch at least one of those boundary valves back to its previous position.

The above scenario is common across the country – from inner cities to rural villages – and within the complexity of the UK’s water network, the open/closed position of valves is often forgotten or overlooked. Usually buried under the ground, a valve can be opened to ensure adequate pressure reaches customers and then left for the next two decades, even after repairs have ensured the opening of said valve is no longer necessary. Valves serve a variety of crucial functions such as dividing and isolating subsections and controlling pressure and water flow. As most are buried in the ground, it’s difficult to know if they are open or closed, but also if they are damaged or not. Worst case scenario, a wrongly opened or closed valve can also influence other measurements too, such as flow and pressure and therefore giving incorrect information about the network’s real condition, which can impact on the utility’s ability to ensure a fully functional water network and best service for consumers.

The Consequences of leaving a network valve open

For utility providers wanting to leave the analogue days of yesteryear – where a valve’s position might be written down on a piece of paper while upgrades are carried out on the network, if it’s noted at all – digitisation can have a massive long-term impact. If a valve is left open after upgrades have been completed, the increased water flow into a specific DMA might affect water quality by disrupting sediment deposits, the lifespan of assets may be reduced due to pressure consistently at upper limits, and leaks may be more commonplace.

All the above can affect a water company’s ability to meet Ofwat dictated Outcome Delivery Incentive (ODI) performance commitments, which has direct financial and reputational consequences. If you multiply the above scenario by hundreds or even thousands of valves across a network, something as seemingly simple as monitoring whether those valves are open or closed should be crucial. And yet, with many valves having been installed in decades past, buried and left until needed, there is still very little in the way of digital monitoring. 

“This is a common problem in cities, where a boundary valve can be opened in a densely populated area to ensure residents receive an adequate supply while repairs are carried out and, because the valve is buried in the ground, it can be left open for 20 years or more,” said Anthony Whittam, Head of Smart Water and Pressure Management, AVK UK, a leading manufacturer of valves, fittings and Smart Water assets for the water and wastewater industries.

“Another example would be when fire hydrants are opened for water companies’ flushing programmes, which generally take place annually. This can cause discoloration of the water, as the change in velocity, flow and pressure disturbs sediment. If the hydrant is incorrectly operated this can have ongoing consequences for water quality. If this can be digitally logged and near real-time data fed to the control room, identification of such incidents are easily rectified. It is also much easier to record for asset management.”