South East Rivers Trust (& the Wandle Trust)

World Water Day – Water in a Changing Climate

World Water Day has been held on March 22nd every year since 1993 to raise awareness of the importance of our freshwater resources. This year, the focus was on the links between climate change and water. We wanted to share with you why this topic is so important to both people and rivers, and what we can all do at home to help.

The 2017 Climate Risk Assessment published by the UK Committee for Climate Change shows that even if global temperature increase is limited to 2°C or less, the UK will experience big impacts in all areas of our lives; from recreation and public health to wildlife and infrastructure.

Water is a key part of how the climate and our landscapes are changing, and we can expect different impacts in different regions. Here are 4 key things to keep in mind.

1. Climate Change is a risk to public water supply.

The South East of England is one of the driest areas in the UK with the highest population density. In Tonbridge (Kent) average rainfall is 650 mm per year, compared to 980 mm in Plymouth, or 1309 mm in Sydney, Australia. So it’s not as rainy here as everyone assumes!

Most water in the region comes from groundwater bodies – underground water stored in the chalk and greensand, which is abstracted by water companies. These rely on gentle winter rainfall to recharge them.

Extreme rainfall events could make the supply of water more vulnerable, as well as reduce its quality, as more water runs off and causes flooding rather than being stored in soils or groundwater.

Hotter, drier summers will increase the demand for water, impacting not only households but also agriculture and industry.

In some areas of the South East, the demand for water could outstrip the supply of water readily available in the local water system within the next decade.

2. Rivers are suffering.

Changing rainfall patterns will impact our already water-stressed rivers. There could be a 30% decrease in river flows during dry periods if we can’t limit warming to less than 2 degrees. At the same time, the risk of extreme flows during wet periods will increase.

Different river systems will be impacted differently. Rivers like the Stour (Kent) are particularly vulnerable to dry winters as they rely on water from the chalk groundwater. Meanwhile the Beult (a tributary of the Medway which flows through an area of impermeable clay soils) is already affected by dry summers, as it is mainly fed by rainfall and water stored in wet habitats.

Water resources are allocated to users such as water companies, spray irrigation for agriculture, fish farms or other industrial uses. The amount currently allocated is far more than can be taken from the river without impacting its wildlife and natural function. We call this over-abstraction and it already negatively impacts many of our rivers. Increasing water demand is putting even more pressure on them.

Low flows near the headwaters of the Wandle in 2017.

3. Water treatment is carbon intensive.

The water sector is the 4th most energy intensive sector in the UK!

Most of this energy is used for pumping water around the supply and wastewater system, and for treating water to drinking standard.

The Water Industry in the UK has committed to become net zero by 2030, but by saving water in our homes we can make this go even further. Water demand is projected to increase due to population growth and climate change. Using water efficiently can help curb this growth in demand as well as reduce the energy needed on cleaning, transporting and heating it.

4. Protecting natural resources is vital.

Protecting and restoring natural processes and habitats can help us create a better environment, protect our water resources and store carbon.

Investing in natural assets such as wetlands or healthy soils can help reduce the need for water treatment by reducing the risk of pollution or even offering water purification through natural processes.

These also retain and store water, allowing it to recharge groundwater bodies, feed small streams and provide shelter to wildlife; buffering our water system to reduce the impacts of extreme rainfall events or dry periods. Vegetation and soils also take up and store carbon, contributing to the global effort of taking up CO2 – a win-win-win offer!

Treating these “natural capital” options as valuable alternatives to traditional hard infrastructure is already being tested and applied by the water industry, food retailers, local authorities and others to increase their resilience. Sustainable agricultural systems aim to integrate these benefits in food production, and every garden or community green space can be an opportunity to contribute.

There are many exciting examples of this (see our Natural Flood Management (NFM), wetland creation and Sustainable Drainage projects below as examples) – but there is still a long way to go to make the most of the opportunities nature offers us.

What can you do at home to help your river and the climate?

There are a few simple ways you can make a real difference:

  • Take shorter showers – a 10 minute shower uses 100 litres.
  • Harvest your rainwater for gardening or even toilet flushing – your plants will like it better and you will not take water from the environment when it’s most needed.
  • De-pave your driveway to allow water to infiltrate – you can help recharge groundwater if you are in the right location, and help reduce flood risk by increasing the amount of water allowed to sink in, rather than run-off.

Should you find yourself stuck at home for a longer period of time, why not set yourself a challenge? See if you can record how often you use water at home, and whether you can reduce it by 10% within a week (but please do keep washing your hands). Let us know how it goes in comments below or on Twitter!