1. POOLE BAY – NEARSHORE REPLENISHMENT TRIAL

2. WHY
“Working with nature” approach -Placing sand on the sea bed to see if the waves will move the sand onto the beach.
Efficiencies – aim to work with local maintenance dredging operations.
“learn by doing” – modelling not possible.

3. How
Contract required the sand to be placed in a 150 x 150 m square box with the smallest possible footprint.
Actual placing was discussed on the dredger
Licence condition sand not higher that 2mCD actual height was 1m CD. After 3 days reduced to 2mCD.

4. Second AWAC position
First AWAC position

5. Dredger record of placed loads

6. Monitoring Silt movement. Turbidity
Sand movement bathymetric, topographic surveys and tracer sand.

7. First Bathymetric survey of completed placement

8. EARLY TRACER RESULTS

11. 21st May 2015

12. 21st May 2015

13. LEVEL DIFFERENCE PLOT

14. SINGLE BEAM SURVEY 27 MAR 2015

15. MULTIBEAM SURVEY 7TH APRIL 2015

16. OBSERVATIONS
Tracer identifies sediment movement onto beach and beach parallel. (none offshore)
Volume difference
17 Feb – 25 Feb = 800m3
25 Feb – 7 April = 1800m3
27 Mar – 9 July = 4500m3

17. Further Monitoring. Bathymetric (November and March)
Topographic ( November and March)
Silt sediment completion March 2016
AWAC in second position until March 2016
Photo’s to record change in beach shape.

18. Both published on www.Poolebay.net
CCO -Reports
Pre-monitoring Report May 2015.
Interim Monitoring Report July 2015.
Both published on
2016 Final report.

19. Further Discussion.
HR Wallingford have recently completed a post project appraisal for another scheme and concluded that 80% of sand moves along our coast frontage in the water.
Do we know how important this is?
Are we investing enough in nearshore monitoring?
Of the 20% moving along the beach how much is wind blown and how much is littoral drift?