Temporary Road Closure - B4337 Llanybydder
A request has been received for the temporary road closure of the B4337 Llanybydder, from a point 563 metres south-east of its junction with the A485 for a total distance of 30 metres in an easterly direction.
The closure is necessary for Carmarthenshire County Council to carry out carry out culvert replacement works from 0900 hours Monday 19th July, 2021 for a period of 6 weeks and 2 days.
The alternative route for east bound traffic will be to proceed in a south-easterly direction along the B4337 Llanybydder to Rhydcymerau to Llansawel road to its junction with the B4310. At the junction, turn right and continue in a south-westerly direction along the B4310 Llansawel to Abergorlech to Brechfa to Felingwmuchaf to Nantgaredig Road. At the junction, turn right and continue in a south-westerly direction along the TR A40 Nantgaredig to A40 Glangwili Roundabout, Carmarthen. At the roundabout, take the 2nd exit and continue in a northerly direction along the A485 Dolgwili Link Road to its junction with the A485 Dolgwili Roundabout. At the roundabout, take the 2nd exit and continue in a north-easterly direction along the A485, passing through Peniel, Rhydargaeau, Pontarsais, Alltwalis, Gwyddgrug, New Inn and Llanllwnni to its junction with the B4337 Llanybydder. At the junction, turn right and continue in an easterly direction along the B4337 Llanybydder to return to a point west of the closure. Vice versa for west bound traffic.
Reason for replacement
Carmarthenshire County Council were asked to replace the Llanybydder Dairy Culvert as a result of a review which concluded that the culvert was hydraulically inefficient and at high risk of blockage. This was evidenced by the flooding that occurred during Storm Callum in October 2018 which caused damage to several properties.
The existing culvert is 1.3m wide, 1.2m high and 2.4m deep to its base and 11m long. The carriageway above the culvert is 7.76m wide with a 2.1m wide footway to the south.
Reason for Closure
When Carmarthenshire County Council designed the replacement, Carmarthenshire County Council looked at the feasibility of keeping one lane open. When excavating to replace a deep culvert or pipe Carmarthenshire County Council need to ensure that the face of the excavation is stable. In order to achieve this, the sides of the excavation are sloped generally at about 45° to prevent collapse. If Carmarthenshire County Council were to replace half the culvert, then only about 2.8m would remain on the carriageway. This remaining 2.8m would need to accommodate the traffic management (baulks/cones etc) and a safe working zone for those working in close proximity to it leaving approximately 2.2m available. The minimum recommended lane width for vehicles under traffic control is 3m and evidently there is insufficient space on site to accommodate this.
Carmarthenshire County Council will again look at ways of mitigating the duration of the closure but this may prove to be structurally difficult to achieve.
There is also a water main to divert to allow the works to be completed.
Pedestrian access will be maintained at all times.
Timing of Closure
The duration of the works is 6 weeks and will have to coincide with the school holidays to minimise disruption.
Alternative routes need to be suitable to all road users including Heavy Goods Vehicles and routes selected are located on the same class road or better than they are currently. There is an acceptance that local traffic will know of other local routes that may be suitable. I attach a plan showing the alternative route for your information.