Hertfordshire’s chalk rivers and the wildlife they support are already showing signs of recovery following the successful completion of a landmark two-year conservation project funded by the Government’s Species Survival Fund.

In early 2024, Herts and Middlesex Wildlife Trust was awarded £1,723,840 from the Government’s Species Survival Fund for its Species Survival in Hertfordshire’s Chalk Rivers project. The fund was developed by Defra and its Arm's-Length Bodies. It is being delivered by The National Lottery Heritage Fund in partnership with Natural England and the Environment Agency. 

As the project concludes, the Trust is celebrating an ambitious programme of river restoration, species recovery and community action that has delivered lasting benefits for wildlife and people across Hertfordshire.

Sarah Perry, River Catchment Coordinator at Herts and Middlesex Wildlife Trust says,

“There are only around 260 chalk rivers worldwide, and 10% are in our area. These rare rivers support vulnerable species such as the critically endangered Water Vole, wild Brown Trout and Kingfisher. Despite their importance, chalk rivers face major pressures from pollution, abstraction and climate change, with droughts and flooding becoming more frequent.

“This funding has enabled us to restore and protect chalk river habitats across 11.59 kilometres of the River Lea catchment, improve climate resilience through enhancing and reconnecting 40.58 hectares of floodplain habitat, and create a further three hectares of new wetland habitat, such as ponds and scrapes, plus a lot more besides. More than 109 wildlife species, communities and future generations will all benefit from the difference this project has made.”

The project had three delivery targets, and over two years, Trust staff, contractors and hundreds of volunteers worked together for transformational change:

1 - River restoration
The project included improving river resilience to low flows and reconnecting floodplains to better manage high flows, regrading approximately five kilometres of riverbanks and reconnecting historic meanders, and raising riverbeds with thousands of tonnes of gravel. Hundreds of woody debris features were installed to create vital fish habitat, while three hectares of new wetland habitat were created across 27 ponds, backwaters and scrapes. One weir was removed and two Fords eased to open up around eight kilometres of migratory fish passage.

2 - Water Vole conservation and invasive species control
Science-led approaches were used to control invasive non-native species, which are responsible for biodiversity loss and destroying native habitats. This included trialling innovative biological control techniques at three locations for Himalayan Balsam – a plant which negatively impacts native vegetation and erodes the soil on our riverbanks and wetlands. Dozens of volunteers were supported to monitor Water Vole populations across Hertfordshire resulting in 7,112 Water Vole signs found across 337 surveyed locations. Alongside this, the maintenance of a network of more than 70 mink rafts took place, supporting the eradication of non-native American Mink which predate on Water Voles, leading to devastating declines in populations.  This has contributed to Hertfordshire becoming effectively mink-free and providing greater protection for the endangered Water Vole.

3 - Community engagement
Community engagement was a core part of delivery, with the Trust supporting communities and groups in Hertford, Ware, Hatfield and Welwyn Garden City to take their own action for wildlife in their local areas.  In total 3,020 people participated in the project, including attendees at the Trust’s first Herts Rivers Week, and those who took up the challenge of the charity’s Pledge a Pond initiative to create their own wetland habitat. Through the project hundreds of volunteers were mobilised for practical conservation work and wildlife surveys resulting in 4,170 hours of support.

Early evidence from ecological monitoring highlights promising improvements. Sarah Perry adds,

“My baseline monitoring is starting to show results — we’ve seen a 177% and 30% increase in river invertebrates, including mayfly and stonefly, at two sites on the River Ash in just one year. Brown Trout are already spawning on newly introduced gravels, and on the River Lea we’ve recorded Teal, Common Snipe, Woodcock, alongside Green Sandpiper on the Ash and Little Egret on the Quin, only three months after new wetlands were created.”

“While the Species Survival Fund project has now reached its end, our work to restore and protect Hertfordshire’s chalk rivers continues. Projects, like this one, are essential for nature’s recovery – and for us all. That’s our motivation to keep working in partnership with funders, landowners, organisations and local communities – we now want to build on this project’s success.”

Find out more about the Trust’s work for chalk rivers at: www.hertswildlifetrust.org.uk/living-rivers