River Beane

The River Beane in Hertfordshire is a tributary of the Upper Lea. Its source is to the north east of Stevenage, near the villages of Sandon and Cromer. The river flows south for around 18km, through the villages of Watton-at-Stone, Stapleford, and Waterford, before joining the River Lea in Hertford.

Problems faced by the River Beane:

The Beane faces many threats including abstraction, impoundment structures preventing fish passage, and sediment from agricultural run-off. Water is abstracted from the groundwater near Aston, a village in the upper Beane, to supply Stevenage and the surrounding villages. Weirs along the river prevent the free movement of fish up and down the river also. Affinity Water pledged to reduce its abstraction from the Beane and since 2017 have done so by an average of 16.18 million litres of water per day. This is one of the largest abstraction reductions we have seen in the area.

Case study: Woodhall Park Phase 1 and 2

Woodhall Park near Stevenage forms the heart of the Woodhall Estate which is a Grade II listed parkland. The iconic Broadwater (lake), the Grade II listed Tumbling Bay Weir and the horseshoe weir downstream forms part of the park, so needed to remain in place on the Estate, although weren’t conducive with good chalk stream habitat and wildlife.

Following a breach in the bank of the Broadwater in April 2016 which drained down the lake, it was realised that, over many years, the Broadwater had filled with silt contaminated with hydrocarbons so required some remediation. The Estate wished to remove the silt and have it treated so it could be spread safely on the land.

We took the opportunity while the lake was being repaired to improve the connectivity of the river by bypassing the two weirs. Phase 1 of the project was completed in January 2018 where we bypassed the horseshoe weir and installed a new meandering channel across a grazing field so that fish could move easily upstream.

The objective of Phase 2 is to bypass the Tumbling Bay weir by installing a new river channel to improve fish passage, create a range of chalk stream habitats, and to split the flow of the Beane between the new channel and the Broadwater so that the lake still exists as part of the parkland, but wildlife can flourish in the flowing, multi-habitat type channel.

 

Design of the new channel around the current BroadwaterDesign of the new channel (dark blue) around the current Broadwater

Once live, the new channel will recreate the natural pool and riffle sequences of a chalk stream. The bed has been gravel-lined and low berms have been installed which will encourage the growth of marginal plants like watercress. The shallow fast- flowing water with gravel bed will encourage the growth of chalk stream species like ranunculus and starwort. Deeper pool areas will provide good habitat for juvenile and adult fish while the in-channel and marginal vegetation will create refuge areas for small fry. Bypassing the Tumbling Bay weir will allow fish to migrate upstream where before they couldn’t.

The most downstream section of the channel, where it re-enters the Tumbling Bay, was made with vertical sides due to the lack of space to create a more naturally shaped channel. To tie this in with the Grade II listed weir, we had the sheet piles clad with brickwork using materials and techniques that match the original weir feature, so the two tie together.
Works are planned to be finished by the end of 2019.

If you’d like to find out more, follow the links to the Catchment Partnership website for the River Lea Catchment or view the management plan for the River Beane.

Woodhall Park House with the BroadwaterWoodhall Park House with the Broadwater

 

The Tumbling Bay weirThe Tumbling Bay weir

Phase 1 new meander just after completionPhase 1 new meander just after completion

Phase 1 in Summer 2019Phase 1 in Summer 2019

The Broadwater and the new channel looking downstream with 80 of work completeThe Broadwater and the new channel looking downstream with 80% of work complete

New brick lined section of channel as it re enters Tumbling BayNew brick lined section of channel as it re enters Tumbling Bay

Design by LTD Design Consultants and build by Garganey Consulting.