Why saving water right now is more important than ever: how drought and water scarcity affect the whole river

Water Scarcity caused by over-abstraction also has a significant and longer–term effect on river levels and while this is often an issue, the extreme weather exacerbates the problem in two main ways. Of course, with rivers already running low from drought conditions, any water abstracted has a greater impact on the river level. But also, during the hot weather, our domestic demand for water increases, sometimes by as much as 30% on the hottest days [6], as we fill paddling pools, water our gardens, and take more showers [7]. This comes on top of our already high water use, with the average person in the UK consuming around 140 litres per day, compared to just 105 litres in Denmark [8]. 

As climate change continues to progress, the Met Office expects our summers to become hotter and drier, meaning these challenges are not going away any time soon.  

What problems do low flows present for wildlife, freshwater environments, and us?  

Low water levels can create a variety of challenges for our rivers and often exaggerate the impacts of existing problems, including pollution. Although untreated sewage spills should, in theory, be less frequent during drier periods, this unfortunately doesn’t necessarily lead to improved water quality. Treated sewage, which still contains a cocktail of contaminants, continues to be discharged into rivers, and when water levels are low, rivers have a reduced ability to dilute pollutants. 

As a result, pollution levels often spike, placing additional stress on the freshwater ecosystems. These spikes, even if for short periods, can be too much for aquatic life to handle.  

One such pressure is the excessive growth of algae such as blue-green algae and blanket weed. Prolonged heat, concentrated pollutants (especially nitrates and phosphates) and less water in our rivers and lakes, creates the perfect conditions for them to thrive.  

Blue-green algal blooms are a particularly visible consequence of these conditions, appearing as large patches of green on the water’s surface, often looking like someone has spilled a can of green paint. These blooms spread rapidly, release toxic compounds, and block sunlight - reducing oxygen levels in the water below. This causes stress to aquatic wildlife, damages the habitats, and can lead to fish deaths. Some species of blue-green algae also pose risks to human health, with exposure potentially causing skin rashes, stomach problems, nausea, eye irritation, and headaches.  

Another increasingly common sight in our rivers is blanket weed - a filamentous alga that forms thick mats of bright green, hair-like strands and thrives in nutrient-rich water. It often resembles, and feels like, wet wool, and can quickly take over sections of a river – something that is happening on the River Test, a chalk stream in Hampshire, this summer. 

As droughts become more frequent and intense, and water companies continue to extract large volumes of water from our rivers, these types of algal outbreaks are becoming a more familiar challenge for our waterways and the nature that depends on them. 107 algal bloom incidents have already been confirmed in England alone this year [6]. 

Beyond pollution, the low water levels and high temperatures impact many wildlife species directly, including fish, such as salmon and trout. These species, and many others, are highly sensitive to changes in river conditions and rely on cool, well-oxygenated water to survive.  

Warmer waters elevate metabolic rates in salmonids (salmon and trout), which can enhance growth and extend growing seasons. While this sounds like a good thing, it can negatively affect their survival. For example, salmon that smolt after only one year are smaller than those that spend two years in the river, and smolt size is a key determinant in their survival. Increased metabolism also means the fish require more energy simply to maintain basic bodily functions, leaving less energy available for growth, reproduction and avoiding predators. 

Their juvenile survival and reproductive success are also closely linked to water temperature, with specific needs for both spawning and egg incubation. Longer, hotter summers can disrupt these natural cycles, such as the annual autumnal cooling of rivers. In 2015, this resulted in a spawning failure in the Rivers Wye and Usk, highlighting the vulnerability of these species.  

Even before spawning begins, drought and over-abstraction can create significant obstacles. Artificial barriers, such as dams and weirs, are a widespread issue in our rivers, blocking the movement of fish through the waterways. Overcoming these obstacles requires a huge amount of energy and as water levels fall, the difficulty increases further, with greater distances between the water and the top of the barriers. Species can find themselves trapped in shallow pools, unable to migrate further, and more susceptible to predation. 

As climate change progresses, droughts (and floods) are only set to become more frequent and more intense and therefore the challenges facing our rivers are only going to get tougher. But there are solutions and ways that we can all make a difference.  

How can we use less water, and help reduce pressure on rivers?  

The hot weather undeniably puts a huge amount of pressure on our rivers and highlights the urgent need for action to improve their resilience to the changing climate. Many of the solutions involve long-term changes, such as the widespread adoption of nature-based solutions that create healthier rivers and more resilient catchments. Through restoring rivers and their surrounding landscapes to a more natural state and making space for water by establishing nature-rich riparian buffers and implementing natural flood management measures, we can support wildlife, improve water quality, and reduce the impacts of both flooding and drought. These approaches also deliver wider benefits, from enhancing farm resilience and productivity to creating blue spaces that support our wellbeing and contribute to stronger local economies. Which is why, along with our Riverscape partners (The Woodland Trust, Beaver Trust, and National Trust) our Making Space for Water campaign calls for the UK Government to support farmers and landowners with funding to create and maintain a network of nature-rich river corridors.

Water companies must also play their part by investing in the infrastructure needed to protect our rivers. Fixing leaky pipes and misconnections is essential as, according to the latest Ofwat data, a staggering 2.87 billion litres of water is lost every day through leaks, that’s a fifth of all the water pumped into the network. Reducing this waste would significantly lessen the need to abstract water from rivers. We also need to see sewage treatment works upgraded to ensure that wastewater is properly treated and untreated sewage spills are prevented.  

Other water-intensive sectors also have an important part to play. Farmers, for example, can help reduce pressure on rivers by adopting more sustainable, nature-friendly practices that improve soil health, water retention, and climate resilience. Government can support these efforts by delivering the actions in our Making Space for Water campaign and making it easier for farmers to install on-farm reservoirs, enabling them to store winter rainfall for use during drier periods and reduce reliance on water company supplies.  

However, there are also actions that each of us can take at home that, when multiplied across millions of households, can make a significant difference, especially during times of drought.  

First, a quick disclaimer, it is absolutely important that we all drink plenty of water, keep ourselves cool and clean, and look after ourselves and each other during these periods of extreme heat. But beyond that, there are some simple water-saving actions you can take to help our rivers: 

• Follow any local hosepipe bans or restrictions. 
• Turn off the tap when brushing your teeth, shaving, or washing up. A simple action that can save up to 9 litres of water every minute. 
• Take shorter showers and choose showers over baths. 
• Only boil what you need, whether it’s a kettle or saucepan – also saves energy. 
• Reuse your “grey water” –Leftover water from cooking, waiting for the shower to warm up, or rinsing veg, can be used to water your plants.  
• Use a watering can rather than the hose, and water gardens in the early morning or evening to minimise evaporation. 
• Install a water butt or barrel to collect rainwater for the garden or washing your car.  
• Sprinklers can use up to 1000 litres an hour, so leave your lawn to go brown! It will bounce back, or you could choose to include more drought tolerant species such as clover. 

Want some more creative ways to save water? Read our blog from last year for tips on reducing your water footprint in your home, around the garden, and even in the digital world.