The Clean Water Bill is likely to be the biggest reform of the water industry we will see in a generation. Delivered well, it could be game-changing for our rivers. Delivered half-heartedly, it risks being a missed opportunity. We asked Alice Eley, our Head of Freshwater, what the bill could mean for Wiltshire's precious chalk streams, and what needs to happen to make it count.

Why are chalk streams so vulnerable? 

Chalk streams are among the most sensitive river systems we have, and that comes down to their geology, hydrology and ecology. Unlike most rivers, chalk streams are fed by groundwater that has filtered slowly through chalk aquifers. That gives them remarkably stable temperatures and stable flows all year round, water rich in minerals, and the famous gin clear look. This stability supports a uniquely diverse mix of plants, invertebrates, and fish. 

 Anything that disrupts that stability has a huge impact on the health of the river. Many chalk stream species are found there precisely because they thrive in stable conditions and are sensitive to changes in water chemistry. Because the chalk filters nutrients out, these rivers evolved under low-nutrient conditions, and so did the wildlife in them. Even small increases in nutrients can trigger algal blooms that smother gravels and starve invertebrates and fish of oxygen. That is especially serious for trout and salmon, which need clean, well-oxygenated gravels to spawn. Chalk streams are also less able to withstand and recover from pollution than rivers fed mainly by rainfall. 
Chalk streams generally carry less water than other rivers, so pollution isn't diluted and flushed away quickly and abstraction makes this worse.

Damaged rivers are less resilient 
 
Centuries of modification have left many of our rivers over-wide, over-deep and cut off from their floodplains. A healthy river spills onto its floodplain during high water levels, which helps to filter out sediment and pollutants just when they are most likely to be washing in. A river that can't reach its floodplain loses that protection and takes the full force of the pollution. 
 

Will tougher governance be enough? 
 
The bill focuses heavily on water company governance, executive bonuses and automatic fines. However that on its own it won't deliver change at the scale our rivers need. 
For governance reform to make a real difference, we need to see: 

• Nature-based solutions at the heart of upgrades, not tacked on as nice-to-haves after traditional engineered infrastructure. 
• Whole-catchment thinking, tackling septic tanks, road and urban run-off and agriculture alongside water company discharges. 
• Water quantity treated as seriously as water quality. We need to ensure enough clean water remains in the environment to support wildlife especially during periods of drought and increasing pressure from climate change. 
• Ecological targets built into compliance, so companies aren't simply chasing ticking regulatory boxes. 

Better data, more transparency 
 
The Hampshire Avon is a priority catchment because of its designation, so continuous water quality monitoring is already being installed here. It is hoped that this data will be made public, so everyone can see where things are changing.  This would include real-time notifications of sewage discharges, along with clear information about why each discharge has occurred and how long it lasts. Greater transparency would help hold water companies to account and give the public a better understanding of what is affecting their local rivers and waterways. 

 
We would also liek to see data that people can easily access and use. Much of Wessex Water's discharge data is online but hard to navigate. Tools like Riverhub help by showing it alongside citizen science data. 
 
Data from Environment Agency testing has also been declining. In an ideal world better resourcing  would provide an independent check on water company data. This goes hand in hand with better recruitment and investment in citizen science, so volunteers have the equipment and technology to collect accurate and therefore comparable data. Reporting and how and what we report on also needs an overhaul on whole river health, shifting from asset-based compliance reporting to ecological outcomes.