When we think about water pollution, we often picture something obvious—a pipe discharging into a river, litter floating downstream, or pollution washing into a stream after heavy rain. But in a chalk landscape like Sussex, the story can be much more complicated.

When it rains, water  falls onto roads, industrial areas, farmland and towns. As it flows across the landscape, it can pick up pollutants before disappearing into the chalk beneath our feet.

The Sussex Chalk Network is investigating what happens next.

Our work is focusing on emerging contaminants such as PFAS, alongside the little-understood impacts of heavy metals associated with road runoff, to better understand where these pollutants are entering groundwater, how they may move through Sussex's chalk landscape, and where they could eventually re-emerge in springs, streams, and rivers.

By connecting the sources of pollution with their potential pathways through groundwater and their impacts on rivers and wildlife, we're building the evidence needed to develop practical, targeted solutions that protect Sussex's water environment.

A Systems Approach - Looking at the whole picture

Traditionally, water quality investigations focus on where pollution is found. The Sussex Chalk Network is taking a different approach. Rather than looking at individual sites in isolation, we're following the entire journey.

We're asking:

·       Where are pollutants coming from?

·       How are they entering the chalk groundwater?

·       Could they be travelling through the aquifer?

·       Where might they re-emerge in springs and groundwater-fed rivers?

·       And what does that mean for wildlife, habitats and the long-term health of our rivers?

By investigating these questions together, we're building a much better understanding of how Sussex's chalk landscape functions as one connected system.

From sources...

Across Sussex there are many potential sources of pollution, including roads, industrial areas, wastewater treatment, and other urban and rural land uses.

These activities can introduce a range of pollutants into the environment, including emerging contaminants such as PFAS, heavy metals associated with road runoff, and other substances that are increasingly being detected in groundwater but their environmental pathways remain poorly understood.

Identifying where these pollutants are entering the chalk aquifer—and which sources present the greatest risk—is the first step towards reducing pollution before it reaches our rivers and groundwater-fed habitats.

...to pathways...

Once pollutants enter the chalk landscape, understanding where they go becomes much more challenging.

The Sussex Chalk Network is investigating whether pollutants from sources such as roads and industry can enter Sussex's chalk groundwater and where they may eventually reappear in springs and groundwater-fed rivers. By bringing together targeted water quality investigations, groundwater monitoring, spring surveys and habitat assessments, we're building a much clearer understanding of these hidden pollution pathways across the catchment.

Rather than making assumptions, we're gathering the evidence needed to understand if, where and how these pathways exist. That knowledge will help reveal the hidden connections between the landscape above us and the rivers that depend on groundwater below.

...to impacts...

Understanding pollution pathways allows us to ask an equally important question—what difference does it make?

The Sussex Chalk Network will investigate how pollutants moving through groundwater may influence water quality, spring ecosystems and the health of groundwater-fed rivers across Sussex. At the same time, we're improving our understanding of how these hidden processes may affect one of the county's most valuable natural resources—its chalk aquifer, which also supplies much of Sussex's drinking water.

By connecting pollution sources with environmental impacts, we'll be able to identify where pressures are greatest and where intervention is likely to deliver the biggest benefits for wildlife, river health and long-term catchment resilience.

...and finally, to solutions

The ultimate aim of the Sussex Chalk Network isn't simply to understand pollution—it's to help prevent it and reduce its impacts.

The evidence gathered through the Network will help guide practical solutions, from tackling pollution closer to its source and improving the management of road runoff, to informing future catchment planning and prioritising environmental investment where it will have the greatest benefit.

Alongside these investigations, we're already putting evidence into action through habitat enhancement and restoration projects, including work on the Lewes Winterbourne, Sussex's designated chalk stream. By restoring natural river processes, improving habitat quality and strengthening ecological resilience, we're demonstrating how better evidence can lead to better outcomes for rivers, wildlife and local communities.

As our understanding grows, we'll also identify opportunities to restore other lost and degraded chalk waters across Sussex, ensuring future action is guided by robust science and focused where it can make the greatest difference.

Building a network for the future

The Sussex Chalk Network is more than a single project—it's the beginning of a long-term commitment to understanding and protecting Sussex's unique chalk landscape.

By bringing together scientific investigation, practical conservation and collaborative partnerships, we're building the evidence needed to understand where pollution comes from, how it moves through the environment, where it has the greatest impact, and how we can target solutions where they will make the biggest difference.

This knowledge won't just help us better understand Sussex's groundwater. It will help guide future river restoration, improve habitat resilience, inform catchment management and support smarter environmental investment across the county.

The project has been made possible through the support of Southern Water and Friends of the South Downs, and we look forward to expanding the Sussex Chalk Network by working with local organisations, communities, landowners, schools and environmental partners who share our ambition for healthier rivers and thriving chalk landscapes.