Beach Nourishment at Greystones North Beach

1 BEACH NOURISHMENT

The proposed beach nourishment program is unreasonable, financially and environmentally unsound and will cause permanent, significant disruption in the town for many years to come.

The proposed development creates a dependency on an ongoing regime of beach nourishment. Without beach nourishment, “the result expected is severely increased erosion of the cliff toe north of the development”. The proposed development effectively “creates a requirement” for coastal protection because it puts a man-made development in an erosion-prone area.

The proposed development is expected to increase erosion levels north of the CPO boundary. As explained on page 257 of the full EIS:

· With beach nourishment, erosion is expected to be “slightly worse than the do nothing scenario”

· Without beach nourishment, there would be “severe erosion at the north end of the bay”

1.1 Reply to An Bord Pleanala by SISPAR regarding beach nourishment

In their reply to An Bord Pleanala dated October 2006 SISPAR conclude that:

· A sufficient supply of naturally rounded land based quarry material for use as beach nourishment material on Greystones North beach was not identified by the developer. This admission alone makes the proposal for an open – ended regime of beach nourishment totally unsustainable.

· The developer is proposing to use material sourced from Ballyhorsey quarry in Wicklow. I believe that the material sourced from this quarry which contains more than 50% broken edges makes it totally unsuitable for placing on a recreational beach where the people will be walking, fishing and swimming.

· The developers proposal is for the ongoing annual transportation of in excess of 12,000 tonnes of the beach nourishment material from Ballyhorsey quarry by road through the town of Greystones and through the proposed new development. The idea of annual convoys of heavy goods vehicles transporting quarried shingle through built up residential areas in Greystones to dump on the north beach is unsustainable boarding on the farcical.

· The Codling Bank which does have suitable material and can be transported by sea but is completely dependent on obtaining a licence from the Department of Communications, Marine and Natural Resources.

It is clear that the creation of a dependency for beach nourishment on Greystones North Beach arising from this development is totally unsustainable and uncertain. Uncertainty exists both from finding a reliable supply of the necessary material and the cost of this material.

1.2 Beach nourishment outside of the CPO area

Clon Ulrick in Section 8.4.2 of his Brief of Evidence states that “The shingle beach nourishment will be placed considerably further north than is envisaged in the Variation to the County Development Plan.” In Figure 3: “Proposed solution, showing modelled cliff-toe development after 30 years” this area will extend well beyond the CPO Boundary up to 214600N. This proposed nourishment scheme will encroach well within the area of a proposed Special Amenity Area Order “SAAO” for Bray Head (Section 8.4.4.3 County Wicklow Heritage Plan 2004-2008). Under whose authority will such an aggressive beach nourishment scheme be permitted in the area of this proposed SAAO?

The COWI Hydraulic Studies and Coastal Morphology Appendix VI Coastal Modelling Report - Coastline evolution, Scenario 4: New development with beach nourishment to hold the line

It states that “It is recommended that the nourished material shall be of the same type as the beach material. The nourishment volumes are assumed to originate elsewhere.”

"Coastline erosion rates vary considerably annually and seasonally and localised single events – such as cliff slides – are smoothed out over time.”

1.3 Commitment from Sispar – only for 30 years with annual cap with no commitment from Wicklow County Council

It is proposed at Section 3.4.5 (Page 254) of the EIS that “the concession company will provide sufficient shingle to limit the beach erosion to a maximum of 21 m at a fixed point, close to the point of maximum erosion, at the end of the 30 year concession period. This is subject to a cap of 6,000m3 (12,000 tonnes) per annum average replenishment if the erosion exceeds predictions. Within the CPO boundary, the retreat will be limited to a maximum average of 10 m. The beach in front of the revetment will be kept a minimum 15 m wide, measured at approximately mean sea level. The beach profile will be measured annually to ensure that the targets are achieved over the 30 year concession period.”

I do not consider that the proposed annual measurement of the beach profile is sufficient. The measurement process must be carried out on a regular ongoing fashion in order to identify sudden beach loss quickly to facilitate a timely response to mitigate against sudden accelerated erosion.

The EIS is silent as to who will be responsible for funding the ongoing cost of beach replenishment following the expiry of the 30 year concession period. There is no commitment from Wicklow County Council that they will fund the cost of this ongoing beach replenishment.

There is no commitment from Sispar to increase the level of beach replenishment material if the erosion rate exceeds predications. This could leave the soft shoreline of Greystones North Beach even more exposed to the increased forces of erosion resulting from a new harbour development.

1.4 Limitations of beach nourishment techniques

Predicting the volumes of beach nourishment materials required and the timing of future nourishment episodes is very inexact. The models used to estimate the 6,000m3 annual requirement used oversimplified assumptions which may very well be way off target.

The ECOPRO Code of Practice (page 66) on the subject of beach nourishment states that:

“without a groyne system to keep the sediment in place replenishment will be periodically required. These ongoing costs should be taken into account when carrying out a cost-benefit analysis.”

Section 3.4.6 of the EIS states that “it cannot be ruled out that the rate of erosion could be higher than that suggested by the modeling, even with the factor of safety. Coastal modeling is not a precise science and 30 years is a long time to extrapolate long term rates of coastal retreat. In addition, long term changes such as changes to the weather patterns or the offshore shingle banks could change the coastal processes and the rates of coastal retreat.”

BEACH NOURISHMENT BASICS by Don Barber, Geology Dept., Bryn Mawr College describes disadvantages to a long term commitment to a beach nourishment which can include:

· “Beach nourishment material often (in fact, usually) erodes faster than the natural material on the beach. A good rule of thumb is that nourished beaches erode two or three times faster than natural beaches. Erosion rates can differ widely, however. The biggest factor for the lifetime of a nourished beach is the number of storms that affect the beach. Storms are unpredictable, so nourished beach lifetimes are unpredictable too. The amount of sand added per yard of beach length and the sand placement design determine the new beach width. Wider nourished beaches last longer.

· Beach nourishment is expensive, and must be repeated periodically. Very few nourishment projects last longer than 5 years without significant costly renourishment.

· The beach turns into a construction zone during nourishment with an ongoing negative impact on the local community and environment.

· The process of nourishment may damage or destroy marine and beach life by burying it, squishing it under bulldozers, changing the shape of the beach, or making the water near the beach too muddy.

· The material added to the beach is often different from the natural beach material. This means that the new material may have smaller or larger diameter sand grains than the natural beach. Such differences in "grain-size" affect the way waves interact with a beach.”

1.5 Further observations relating to proposed Beach Nourishment at Greystones North Beach

· The developers believe that the only viable option for sourcing the beach nourishment material required is to pump it ashore from the Codling Bank. They state that the material required “is generally found along beaches and rivers and is not in very plentiful supply from quarries operating in Ireland”. The Codling Bank option provides the rounded material which is not obtainable form land based quarries.

· However the developers would require a licence from the Department of Communications, Marine and Natural Resources to retrieve material from the Codling Bank. However the likelihood of being granted a licence is uncertain.

· The removal of offshore gravel from the Codling Bank can have direct and often unforeseen impacts on coastal stability as it influences sediment availability as well as inshore wave and current influences on the coast. As very little sediment, other than mud is now entering the Irish Sea the existing sand and gravel deposits on off shore banks such as the Codling Bank are a non-renewable resource.

· The recommended option of the developer is “to develop a yearly beach nourishment programme with material brought in by road from local quarries in a safe and organised manner.” This is therefore a very short term plan even though they have already committed to this for 30 years.

· This option appears to have been selected reluctantly by the developers arising from the many negative impacts resulting from it. This proposal will therefore result in the dumping of material which is inappropriate for a recreational beach (angular stones with sharp jagged edges) using road transport with obvious negative traffic impacts.

· Also it is clear that the developers expect the land based quarry material to erode much more quickly than the Codling Bank material. They state that if Codling Bank material were to be used that “beach nourishment could be carried out in 5 to 10 year periods”. This compares to the annual beach nourishment required if land based quarry material is used.

· The potential effects of climate change with rising sea levels and increases in the intensity and frequency of storms and sea surges do not appear to have been considered by the developer in regard to their beach nourishment proposals. It is likely that future sea level rise will increase the volume of material needed for nourishment if the coast is to be maintained in its present position. This will increase both volume and costs of future nourishment materials. The estimate annual requirement of 12,000 tonnes of nourishment material may well increase dramatically over the years. This raises very serious issues with regard to the long term financial affordability (and viability) of this very long term financial commitment.

· I have been advised by Professor Orrin Pilkey (James B. Duke Professor of Earth Sciences) that “the experience in the USA is that there is no guarantee that beach nourishment will continue forever. So promises to prevent erosion forever by nourishment are hollow.”

· The beach nourishment proposal is therefore unsustainable from financial and material sourcing perspectives.