As the UK gets warmer, the summers are likely to be warmer and drier, particularly in the South East. However, rainfall is likely to become more intense.
The main impacts of changing weather patterns on the water infrastructure across the UK include:-
- Droughts – Hotter, drier summers will lead to lower flows in our rivers and boreholes which will leave less for abstraction for water supplies. (Water abstraction is the process of extracting water from natural sources like rivers, lakes, springs, or groundwater, typically for agriculture, industry, or drinking water supply.) In warmer conditions, loss of water due to evaporation also becomes a much bigger factor and the demand for water also increases when its warmer
- More severe downpours and floods are likely to challenge the current approach to drainage.
- Rising temperatures and less frequent, more intense, rainfall will reduce the quality of the water we take from the environment, resulting in the need for more treatment. Also, lower flows in the rivers that wastewater treatment works discharge into will result in the need to improve wastewater treatment, which will increase operational costs and carbon costs.
- Drier summers and wetter winters will result in shrinking and swelling of the ground placing added pressure on our aging water supply pipes and sewers, which could increase leakage. Also, the UK’s old reservoirs may need improved overflow arrangements and the old earth embankment reservoirs will have to be monitored closely to ensure that they can cope with the changing conditions.
The impact these challenges are creating, coupled with the need to decarbonise the system, reach net zero, and public pressure to fix the issues (particularly sewage overflow) has created a minefield for water companies, Ofwat, and government.
Many of our European neighbours are struggling to maintain water supplies now and this has led to tensions between the need for water for agriculture, tourism and the environment. The UK is likely to see similar problems in the near future unless the issue is tackled. The National Infrastructure Commission predicts that without further action there is roughly a 1 in 4 chance over the next 30 years that large numbers of households will have their water supply cut off for an extended period because of a severe drought.
In 2018, the NIC produced its Preparing for a drier future report: England’s water infrastructure needs. The report concluded that there was a need for an additional 4,000Ml/d of water. A twin-track approach was recommended to delivering the additional water: –
- Provide 1300Ml/d of new supplies (equivalent to needs of 9million people)
- Reduce demand by 1350Ml/d by reducing leakage by 50% by 2050 and reduce demand by 1350Ml/d by reducing consumption from 141 to 118litres per person per day
The recommendations have resulted in a big drive to reduce leakage. In addition, over the last five years, Ofwat has worked with the Environment Agency, the Drinking Water Inspectorate (DWI), and water companies to develop solutions which would deliver the additional water recommended – this was called the “Rapid” programme. Many of the recommendations are to be implemented over the next ten years.
Around 325,000 English properties are currently at high risk of flooding caused by heavy rainfall. Known as ‘surface water flooding’, this type of flooding can cause major disruption to people’s lives and livelihoods. According to the NIC, without action, climate change and urbanisation could put an additional 230,000 properties at high risk by 2055. Action is needed to both increase the capacity of pipes and sewers and capture more rainwater before it enters them.
Increasing the use of sustainable urban drainage systems (SuDS) and exploring nature-based solutions will be essential. Each of these tools has multiple benefits.
SuDs help prevent the sewage system from becoming overloaded by managing surface water from rainfall. This helps prevent sewage overflows and decrease pollution. Keeping rain and wastewater separate will also reduce the need for costly and energy intense treatment, reducing carbon impact as well.
The Institution of Civil Engineers has joined others in calling for government to implement Schedule 3 of the Flood and Water Management Act 2010, which would make SuDs a mandatory requirement for developments over 100m2.
Nature-based solutions can be an effective way to mitigate increased flood risk from climate change and can also provide benefits like green spaces for the public to enjoy and cleaner air. Ofwat’s intention to deliver £2b of nature-based solutions and to increase biodiversity on water company land is certainly a step in the right direction.