Renewing 3 timber groynes at East Cliff
09 October 2023
Timber used for the new groynes
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 length. Approximately 225 planks of timber make up a groyne. Generally only the top 5 rows are constructed using new timber; recycled timber is used for the bottom 12-14 rows. Timbers unsuitable for re-use on new groynes are recycled for other projects; for example in 2022, for cladding and decking at the Eco Hub at Durley Chine, and as part of a 1.2km footbridge created at a wetland scheme in the Tamar Valley, Cornwall.
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 2022/23 – 4 groynes adjacent to Bournemouth Pier
- Winter 2021/22 – Year 2 of a two-year rewnewal programme, 4 groynes from Middle Chine to West Cliff zig-zag
- Winter 2020/21 – Year 1 of a two-year renewal programme, 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