Councillors approve plans for flood prevention scheme on A38
The Somerset Rivers Authority (SRA) has now agreed to de-silt Haywards Water under the A38
A key road between two Somerset towns will be better protected from flooding following changes approved by local councillors.
Blackbird Bends comprises two bends on the A38 between Wellington and Taunton, near the Blackdown and Willowbrook garden centres and the Blackbird Inn bed-and-breakfast.
This stretch of the A38 lies near the confluence of Haywards Water and Hockholler Stream under Hockholler Bridge, making the road prone to localised flooding.
The Somerset Rivers Authority (SRA) has now agreed to de-silt Haywards Water under the road to allow the streams to flow more smoothly into the River Tone.
Up to £20,000 will also be spent on a flood prevention study focused on the nearby weir.
Both measures were approved when the SRA board convened near Bridgwater on January 20.
A spokesman said: “De-silting bridges and culverts, and re-aligning channels close to highways structures, improves the flow of watercourses, and increases the volumes of water they can carry.
“This reduces the risks of flooding for roads, nearby homes and land. Whole systems can work more efficiently when watercourse bottlenecks are removed.
“The aim here is to de-silt Hockholler Bridge as an interim measure while a detailed study is carried out.”
The A38 serves as the main diversionary route through Somerset when the M5 is closed or congested.
In the recent past, flooding at Blackbird Bends has let to one or both lanes of the road being shut, causing congestion and disruptions for both residents and busineseses.
Improvement schemes were previously carried out on other stretches of the road, with a new drainage system being installed at Rumwell in early-2018 and a similar scheme being implemented in Chelston in 2019.
The SRA commissioned a previous study in 2019, which identified that Haywards Water had sufficient capacity for “all but the most extreme flooding events” and therefore did not need to be widened.
David Jones, highways asset commissioner at Somerset County Council, said that the capacity of the stream was being affected by silt qualities, and that further studies were needed to see whether the nearby weir was impeding the flow of silt downstream.
He said in his written report to the SRA board: “Excessive siltation in Haywards Water was being caused by the low flow speed through the system.
“The low flow speed was likely to be the result of a weir in the field immediately downstream of the main culvert.
“It is understood that the weir has been altered in the past by the landowner,but it is not known for what reason, what the alterations were or the effect of the alterations.
“The root cause of the flooding at Blackbird Bends now seems to be a flow issue rather than a capacity issue, which in turn could be linked to the downstream weir.”
Up to £20,000 will be spent on this study, which will look at whether the weir needs to be altered and options for reducing sediment levels in the short-term.
The SRA hopes that the study can be completed by late-spring, with any resulting funding bid being included in the budget for the 2024/25 financial year.
The funding for both the de-silting and the weir study will be confirmed when the SRA board meets to set its annual budget on March 3.