Water voles set to benefit from removal of River Stort weir
The removal of the weir from the River Stort at Grange Paddocks, a popular paddling spot for children and dogs, is expected to take place this autumn or spring of next year.
Following a feasibility study, Hertfordshire County Council and the Environment Agency (EA) have completed the detailed design for the works – which will include the creation of steps leading down into the water – and the restoration of habitat.
Water voles are expected to be one of the beneficiaries of the improvements. Surveys carried out in August 2021 and May this year showed no signs of semi-aquatic rodent activity in the construction-affected area, although small populations have already been recorded around Grange Paddocks.
On-site checks will be carried out before and during the works for voles, a vital element of river ecosystems. The ultimate goal is for the weir removal to encourage voles to migrate and colonize upstream.
As part of the spillway removal project, contractors will use imported gravel and timber flow deflectors to restore the section of the waterway near the recreation center and playgrounds to a natural chalk river.
The program also includes bank protection measures; an updated EA telemetry point for river level measurement and flood warnings; an upstream wetland off Bourne Creek to provide additional habitat diversity; and the creation of safe and informal steps leading to the river near the current weir.
The next step is to obtain an “Impound Permit” from the EA. This will include a public consultation where, similar to a development application, stakeholders and members of the public can submit comments.
An authorization for an activity at risk of flooding EA will also be requested. Modeling shows that removal of the spillway will reduce risk in many areas, both upstream and downstream, including residential and commercial properties. The study did not indicate any increased risk of flooding for the buildings.
The agency and county council liaised with police to discuss the safety implications for riverside homes related to the spillway removal. The force was confident that the combination of the deep waters of the river combined with the vegetation cover would continue to provide good defensive protection. Agents were also happy to advise owners.
In March, Bishop’s Stortford Borough Council and its Waterside Stortford partner, the Canal & River Trust (CRT), teamed up with the Environment Agency to create a habitat for the creatures, one of the declining mammals fastest in the UK, installing a 60m stretch. pre-planted coir rolls along a steep bank of Stort Navigation, close to the Goods Yard walkway.
In 2015 the Essex Wildlife Trust and Herts & Middlesex Wildlife Trust re-established a population of water voles on the Stort below Thorley Wash Nature Reserve.