Thursday 09 January 2014
Environment Department response to media enquiry from Guernsey Press.
Guernsey Press Enquiry:
Environment was successful in having its plan for coastal defences accepted by the States accepted in June.
This focuses work around St Sampson's Harbour and Belle Greve.
Can the department justify prioritising these two areas over others, given the damage at Perelle, Portelet and L'Ancresse?
This would be for tomorrow's paper
Environment Department Response:
The Environment Department welcomes the opportunity to clarify the funding streams for coastal defence flood risk project as there are two separate issues raised in this enquiry.
The sea walls, rock revetments, piers, slipways and shingle banks, all of which act as coastal defences, are maintained by the Department and funded through its annual revenue budget. The coastal defence budget for 2014 is £77,000 and the recent storm damage at Fermain, Saints and Portelet will be covered from this budget. From time to time major works are necessary - the repairs at breached walls at L'Eree and Perelle, and the construction of the retaining wall built at Albecq in 2009 - such works are funded from capital rather than revenue. The Department has a small capital allocation but if this is insufficient the Treasury and Resources Department will consider the merits of each project before agreeing funding from central capital reserves. The Departments budgets are reviewed annually and hence any demonstrated need for increased expenditure on maintenance or repair can be addressed as part of the annual budgeting cycle.
The Environment Department's report to the States in 2013 is a new project, focused on preventing coastal flood inundation due to sea level rise predicted with climate change. This is very different to preventing overtopping (30m high sprays) experienced on the west coast under certain storm conditions.
The report followed the 2012 study of seven localities - Baie de Port Grat and Pequeries; Belle Greve; Bordeaux; Cobo and Saline Bay; Rocquaine and L'Eree Bay; and St Sampsons Harbour with associated area of Grande Havre. These areas were identified by Royal Haskoning in the coastal defence strategy of 2007 as vulnerable to impact through rising sea levels. Pembroke was also studied in 2012, although the surrounding area had not been identified as at risk of flooding with sea level rise the Environment Department wanted to explore the options for managing coastal defence there.
The predicted relative levels of sea level rise, as published by the Intergovernmental Panel on Climate Change in 2011, were 0.13m between 2011 to 2031, 0.38m to 2061 and 0.90m to 2111. The modelling of the coastal defences in the study areas was based upon these predictions and illustrated the impact of sea level rise under different wind and tide conditions and the area inland that would be flooded at high tide as a consequence of sea level rise.
The results of the study were widely circulated and consultation started in late summer 2012. 'Drop-in' sessions with displays of maps and the locality reports let Islanders see for themselves how their houses or businesses, schools and roads could be affected by flood risk from rising sea levels. They could also see the range of options proposed to protect the respective areas.
Evaluation of each flood risk area was then done to scrutinise the number of homes, businesses, road infrastructure, schools, surgeries, and other community service providers, together with gas, electricity, water service provision, would be directly affected in the area in sea level rise. The impact on the natural environment was also considered alongside the socio-economic factors. A process of weighting according to the number of properties and services affected was calculated which gave the order of priority for each of the areas identified as at risk of coastal flood.
The States agreed with the process of evaluation and, subject to capital funding being made available, the order of prioritisation for works to each area. The order of priority is currently: St Sampsons, Les Banques, Cobo/Saline Bay, Baie de Port Grat and Pequeries, Bordeaux Harbour, Rocquaine and L'Eree, Pembroke Bay.
The States also agreed that the first two areas of priority for defence works were St Sampsons Harbour and Les Banques. Work is now underway to first identify the most cost effective defences and then construct them to protect the immediate coastal area and the low lying land beyond them from sea level rise at each location.
Obviously there is limited capital funding available for construction projects of this nature and a phased approach to introducing the new defences for sea level rise at these areas was necessary.
The areas identified as at risk will be re-evaluated after St Sampson's and Belle Greve Bay have been protected (estimated to be in four/five years). St Peter Port and Perelle will also be included in this evaluation which the States agreed should be included following amendment to the report.
It should be emphasised here that the funding agreed by the States in 2013 is for improvements to defences to reduce flooding damage due to predicted sea level rise.
Deputy de Lisle has suggested that the prioritisation for works should be re-evaluated or capital funding diverted to enable earlier works for parts of the west coast. Neither St Sampson's Harbour area nor Les Banques suffered serious damage in the recent storms but the flood risk from predicted sea level rise remains. If funding for defence projects for St Sampsons and/or Les Banques is diverted now these two areas may be set back to a point where essential infrastructure or business operation may be put at serious risk. Such a change of direction may cause loss of confidence in the business community in the States' ability to look beyond localised issues.
In illustration of a small part of the evaluation in setting priorities for coastal flood risk defences it may be helpful to point out that the weighting for residential homes alone in the flood risk areas at St Sampsons and Belle Greve was 42,450 and 86,030 respectively. The weighting for commercial properties at St Sampsons and Belle Greve was calculated at 918,830 and 839,400 respectively.
At Rocquaine/L'Eree the weighting for residential homes was 10,193 and for commercial properties 39,210.
As well as much larger residential and business communities the two areas in the north of the island contain the island's electricity station, commercial harbour, oil and gas stores, and sewage disposal plant.
The Environment Department is not unsympathetic to the many people who have suffered damage to their properties due to waves overtopping and inconvenience as roads were closed to allow for clearance. The sustained storm conditions recently were outside many islanders' experience and people living alongside the coast were particularly affected with sea water pouring onto their gardens, and sand, weed and pebbles.
However it must be appreciated that the power of the sea under such conditions means that it is unlikely that it will ever be possible prevent storm driven waves causing damage given the road and extensive property development that is concentrated around the flatter areas of the east and west coast.
It is of course possible to construct defences of great height that could give protection from a proportion of storm overtopping. Such high defences would be very costly to construct and, the Department would suggest, so visually intrusive that coastal views would be considerably changed and much of the pleasure that people derive from living in Guernsey would be lost. The attraction of the island's coastline to visitors would also be substantially reduced. In addition the taller the defence the greater the undertow /suction at the base of the wall and hence the greater the depletion of sediment at the base of the wall.
Installing rock armour on beaches would help protect the base of sea walls but enormous quantities of rock revetment would be required if it was to make a significant difference to reducing the level of spray and wave overtopping we regularly seen around the coast at high tides. Introducing these very large quantities of rock would be expensive and the public would need to balance the changed appearance of many beaches and some limitations to how they currently enjoy them for any reduction in the damage or inconvenience currently caused by waves overtopping.
The Department has quite properly examined the issues and reported to the States. The States have been afforded the opportunity to prioritise the capital spend. The States has decided that the priority, as far as coastal defences is concerned, is to protect the highest density most economically significant areas of the Bridge and Les Banques. When prioritising capital spending with limited funds a balance has to be made between planning essential infrastructure for the future and managing existing facilities. However, as for all long term projects, reviews will be carried out in the coming years and if circumstances change such that a different order of priority is demonstrated as being appropriate then of course the project priorities will be reviewed.
Contact Information:
Environmental Services Unit
Environment Department
Tel: 717200
