Year 2 of a two-year, £1.9 million programme to renew eight timber groynes from the boundary of Poole/Bournemouth to West Cliff zig-zag
4th October 2021
All 53 timber groynes along Bournemouth’s beaches are being renewed, in multiple short phases, as part of the Poole Bay Beach Management Scheme 2015-2032
This fifth short phase is the second year of a 2-year programme covering the frontage from the Poole/Bournemouth boundary to West Cliff.
Last winter the first set of groynes in this two-year programme were renewed, from the boundary to Middle Chine. Five groynes were deconstructed, replaced by four more evenly spaced ones. This winter works continue from Middle Chine to West Cliff zig-zag path as indicated on the diagram above. Three old groynes will be replaced by four new more evenly spaced groynes.
For details of the Environmental Innovation Hub indicated on the working area diagram, please visit bcpseafrontprojects.net/durley-chine. Some old groyne timber which can’t be recycled into the new groynes will be used to clad parts of the Hub.
Our contractors Suttle Projects Ltd, arrived on site on 4th October. They will be deconstructing and reconstructing the groynes, working Monday to Saturday, from 7am to 7pm. They will work on multiple groynes simultaneously and flexibly with the lowest tides on a rota system which may occur outside daylight hours. The sequencing and delivery of the programme is calculated to deliver the greatest efficiencies in the shortest period. We anticipate the works will be finished by spring 2022.
Deconstructing and reconstructing a timber groyne – how it’s done
Please enlarge images in the gallery for a description of the process
Timber used for the new groynes
Each new groyne will be constructed using a mix of new tropical hardwood timber and recycled tropical hardwood planking, from previously deconstructed timber groynes, when available.
Hardwoods used will be Greenheart – a pale yellow to dark olive green wood from Guyana, South America, and Ekki – a dark red / deep chocolate-brown wood from West Africa and the Congo. These timbers have been selected for their strength, durability and resistance to marine life which can destroy wood by boring into and eating it.
FUNKY FACTS ABOUT POOLE BAY GROYNES
A total of 29 piles are sunk for a timber groyne, each pile is 10m long and spaced 2.5m apart. The King pile (out at sea) is 12.5m long. Piles are driven down to the first solid layer of stable substrate/clay. Each groyne is between 5m-7.5m deep and roughly 75m in width. Approximately 225 planks of timber make up a groyne. The top 5 rows are generally constructed using new timber; recycled timber is used for the bottom 12-14 rows.
Visitor access & safety
Access along the promenade, and to beach huts, will be maintained to enable you to pass the works, but areas of the beach are restricted for safety reasons. The sand becomes very unstable when it is excavated around groynes. For this reason, please do not enter or pass the construction zone along the water’s edge, even at low tide. Dogs should be kept on a lead.
Once work is finished, restrictions will remain in place until the sand dries out and becomes more compact and stable underfoot.
All the groyne renewal works will be carried out in accordance with the Marine Management Organisation licence and planning consent. Additionally, new tropical hardwood timber used for this project is certified sustainable by the Forestry Stewardship Council (FSC).
The old groynes will be carefully deconstructed to ensure that all suitable materials can be recovered and recycled or re-used in future coastal projects.
Groynes – their role in coast protection
Beach material generally moves from west to east in Poole Bay. The strategically placed groynes are renewed approximately once every 25 years and slow down the natural processes. Piling and planking deep into the beach to the first solid layer of substrate/clay helps retain the sand within the groyne field.
In combination with periodic beach renourishment (topping-up the beach levels) the groynes also help protect the seawalls and cliffs from erosion. We last renourished some of the beaches from Poole to Southbourne in early 2021 [details here].
Previous phases of timber groyne renewal:
- Winter 2020/21 – Year 1 of a two-year renewal project, 4 groynes eastwards from Poole/Bournemouth boundary to Middle Chine
- Winter 2017/18 and 2018/19 – 12 groynes at Southbourne
- Winter 2016/17 – 8 groynes eastwards from Fisherman’s Walk to Gordon’s Corner
- Winter 2015/16 – 10 groynes from the east of Boscombe Pier to Fisherman’s Walk