Water is the most essential resource for human survival. To drink, to stay clean, to stay cool in the heat, to create our food and to clear out our waste, water is at the heart of everything we do in life.

With how easily accessible water is in most of the developed world, we can sometimes miss how scarce a resource it actually is. However, coming into a year where due to hot weather, droughts are happening across the country and hosepipe bans start coming into effect, we must be as efficient with our water as possible.

From a water supplier and network perspective one of the key areas to point and look at is the wasted water and so by extension, the leakage. Leakage is often defined and calculated not just as the water we know is leaking out of mains, but as all of the water which we can’t account for. This is calculated by measuring the amount of water we put into the network, and then taking out all of our different usage components. With this, we consider our leakage to be the lost water, the bits that escape and the more scarce a resource water becomes, the less we can afford to lose a significant amount to the network. Across England and Wales we lose approximately 3 billion litres of water a year to leakage and there are many ways to try to reduce that but a key arrow in any water companies quiver is pressure management.

There is always a fine balance with network pressures. If water pressures are too high, mains are more likely to burst and existing leaks in the network will lose water at a much faster rate. On the other end of the spectrum, if pressures get too low, customers can be hit with notably low pressure or even go without water which is obviously an incredibly undesirable outcome for our customers who we ultimately as a business exist to serve.

Without intervention, pressures in water mains are predominantly influenced by the makeup of natural landforms and how they elevate and lower themselves based on the hills, cliffs and slopes that make up the different altitude. To solve the first problem of ensuring everyone has enough pressure in their water systems to supply their property we must look at where we expect the properties with the lowest pressure to be (usually at the highest elevation point) as if they have enough water everyone should and then we build out from there.

The first line of defence against high pressures is our network design. How well can we group the properties within our different elevation bands. If we’re targeting our pressures around our customer with the highest elevation, can we group their supply with other customers of a similar elevation so there isn’t a large variation of pressures within an area. This isn’t always possible however with natural topography and landforms, we don’t always have the option to group properties together by their elevation at which point we have to look at how we can manually control pressures,

By installing new Pressure control valves (PRVs) we can gradually wind down pressures in different areas to reduce their leakage which is obviously a brilliant outcome for water networks but as with most things, it’s not quite that simple. The complications come in when we start to look at cost and value. There are a lot of ways to look at this problem is it better to spend a lot of your time and money on one big solution that can impact a huge number of properties but can’t be as sharply fine-tuned as specifically because of the size of the area it has to cover. Or would it be more effective to manage multiple smaller areas where you can have bigger pressure reductions but won’t get the same level of impact and will have to install more assets and have a larger number of network assets to manage.

These solutions of network configuration and installing new assets can be a cost-effective method of reducing leakage that don’t just fix the problem now by repairing one leak while we wait for the next leak to break out, but rather improves the longer term behaviours of the mains to make them less likely to burst. On top of this, installing a new pressure control valve only requires digging once and then making all the leaks smaller whereas going out and fixing all of the leaks individually requires multiple digs and far more detection and scheduling resource and relies on consistently completing multiple steps in the build up being done correctly.

While these solutions all sound fantastic, the reality can often provide many more challenges. Going back to designing around natural topography the first problem is we aren’t building networks from scratch. We have to look at what the network looks like now, what can be done to adjust it and what complications that could bring. We have to think about future planning, one example is that as a country there is currently a housing shortage so if we build a solution best suited to deal with a thousand properties, what happens if a new development gets added on or is being planned? Will our assets still work? Further how do we make our ideas work and adapt our designs when we hit challenges? If one property would face low pressure issues as a result of our works, should we give up on a project that could pressure manage thousands of properties? In most cases, of course not! But you can’t tell a customer they have to deal with no water to their house for the greater good, so you have to find a solution that fixes the problem for that customer. There could be many solutions such as installing a private booster system to pump water up to wherever their property may be, alternatively moving valves and changing network configuration to put them into a higher pressure area.

There are almost always solutions to problems that could derail a project and the water industry is no longer in a position where they can afford to let these problems halt progress. We have to be prepared for worsening water scarcity as climate change reduces rainfall and raises average temperatures. Coupled with a steadily increasing population, we must not be derailed by blockers and continue to push through and innovate so we can ensure that we are able to work around issues and be prepared to meet the demands of our communities.

By Iain Price

Iain Price is Project Manager at Skewb. To speak with him about this topic in more detail, you can connect with him on LinkedIn.