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This publication is an evaluation of the reasons for the rising beach levels on West Wirral that is causing sand to be blown by the wind over the sea walls and onto highways and private property. It specifically examines the management arrangements that will need to be put in place by the Metropolitan Borough of Wirral to cope with the predicted on-going process of rising beach levels.

The area has a diversity of uses that have been fully considered in developing management options. It presents the preferred policies for managing rising beach levels and the increasing problem of wind blown sand.
The wind blown sand problem is going to get worse. The processes outlined below shows why this is the case, in particular why the beach levels are rising, and will continue to rise. The Metropolitan Borough of Wirral has to  take the decision of how to respond to this change, it cannot stop this change. The wind blown sand issue is not the result of recent actions by the Metropolitan Borough of Wirral but is connected with the geomorphological evolution of Liverpool Bay and the Dee Estuary over the last 10,000 years.

The Process of Change
Historical Background
The Dee Estuary in common with most West Coast estuaries has accumulated sediment since the end of the last ice age, over 10,000 years ago. In the early nineteenth century the East Hoyle Bank was separated from the north Wirral shoreline by a channel known as Hoyle Lake. This channel has filled with sediment during the 20th century. The natural filling was artificially helped by the dredging, in the River Mersey, of the main Crosby and Queens channels and by the construction of training walls early in the 20th century. These actions had the effect of diverting most of the tidal flows  into the main Crosby and Queens channel, thereby weakening tidal scour in the Rock and Hoyle Lake channels.

As the Dee Estuary fills with silt and sand it is becoming shallower. This shallowing has the overall effect of reducing the volume and so the tidal energy within the Estuary, thus making longer-term build up of sediment, in particular silt more likely. Sediment is supplied to East Hoyle Bank from the North Wales coastline, from offshore in Liverpool Bay and to a lesser degree from upstream in the River Dee. In recent years the Welshman's gutter, a channel between the Hilbre Swash and the Welsh Channel has closed.
This indicates a redistribution of tidal flows at the mouth of the Estuary towards the Welsh shore.

The Rivers Dee and Mersey carry high loads of suspended silt. This tends to settle when and where conditions are calm and currents are slack, for example on the lower-lying shore between the former Hoyle Road baths and Kings Gap. Areas of deposited silt are ideal for the development of saltmarsh vegetation. Isolated inter-tidal vegetation interrupts currents and thus has the ability to precipitate further silt deposition.

The rocky outcrops of Hilbre Island, Little Hilbre, Little Eye and Tanskey Rocks direct tidal flows in Hilbre Swash (west of Hilbre Island) away from  the coastline and also shelters the Wirral coast including West Kirby shoreline from westerly wave and tidal action.

Along the west-facing West Kirby shoreline the seaward protrusions of Hilbre Point and the extended Marine Lake form the flanks of a shallow bay. Sediment naturally accumulates in such a bay, silt where conditions are calm and sand where currents are stronger. Sand, when dry, is blown onto the dunes and promenades at the landward edge of the shore.

Recent changes at West Kirby
A former tidal channel between the eastern side of Hilbre Island and West Kirby foreshore has disappeared due to beach accretion. In addition the sediment appears to be becoming siltier. These changes are related to the decreasing tidal influence in this section of the Dee Estuary and may also be related to the extension of the Marine Lake during the 1980s.

The marsh at West Kirby in front of Royal Liverpool Golf Club is established and developing. It has been constrained from moving along the beach southwest towards Dee Lane by a combination of beach cleaning and intense public use. Wind-blown sand naturally collects in the three-sided enclosure formed by the lake car park, the promenade and the edge of the marsh. In the absence of human intervention, this area would have become vegetated. The present high sandy beach at Dee Lane is rarely covered by tides, thus enabling dry sand to blow onto adjoining highways and private properties.

Recent changes at Hoylake
A study of East Hoyle Bank in 1970 determined that 'the net direction of sand transport is from west to east and is caused by wave induced currents. This study also noted "evidence that sand is transported by wind on the highest parts of the Bank'. The Bank has gained height and width since 1970, exposing greater areas to the drying effect of wind. The strongest winds blow from the west, so that the potential for wind-blown sand transport onto Hoylake shoreline is now correspondingly greater. The sustained long-term saltmarsh development is considered unlikely on this part of the shore because of its exposed nature. Levels in the low areas are rising at an average rate of 30mm per year. This trend is likely to continue, with sand from East Hoyle Bank blanketing the silt, until an equilibrium is reached, when the shore attains sufficient height to enable westerly winds to move excess sand onto the coastline.

The Meols Channel originates in the remains of Hoyle Lake, immediately west of Hoyle Road old baths site. Annual shore profiles indicate that the pond-like depression around the promontory is filling with sediment and moving east, away from Hoylake towards Meols.

How widespread is the problem?
Problems with blown sand occur at other sites within the Liverpool Bay area, notably at Lytham on the Fylde coast and at Crosby and Southport on the Sefton coast.

At Southport blown sand collects on the upper beach, the rate however is such that it allows the development of low fore dunes. The rate of dune development and the height of the dunes do not give rise to concern and the low dune system protects the base of sections of the sea wall and stops blown sand from moving from the beach to the adjacent highway. The low vegetated fore dunes are resilient to wave action and the vegetation rapidly re-colonises and traps more sand following erosion.

Studies support a view that it is better to 'manage' fore dune type habitats rather than have no such habitats at all.

The Legal Constraints
The Dee Estuary is designated under the Convention for Wetlands of International Importance under the Ramsar Convention and as a Special Protection Area under the EEC Directive on the Conservation of Wild Birds due to the extent of its wetland habitats and the numbers of waterfowl it supports. The Dee Estuary and North Wirral shore are notified as Sites of Special Scientific Interest (SSSI) under the Wildlife and Countryside Act. There is an internationally important wader roost in the winter months, this is protected by the above legislation. Red Rocks is designated as a SSSI by virtue of the dune habitats and other wildlife interest such as natterjack toads and sandhill rustic moths.

English Nature, the advisory body to the government on nature conservation, advises the landowner on what is not permissible on a SSSI, although there is room within the regulations to enable landowners and managers to apply for consent for certain activities. This fact is fundamental to the present issue because any management action proposed to address the wind blown sand and habitat change will need to be consented by English Nature. For instance the practice of ploughing Spartina and other species of grass is not consented and is therefore illegal Metropolitan Borough of Wirral is the planning authority for all land above low water mark in the area including the beach.

All coastal local authorities are required by central goverment to produce a Shoreline Management Plan (SMP) to outline to their strategic approach to shoreline management. The Liverpool Bay SMP covers the area from Llandudno to Formby, and provides the strategic framework within which Wirral’s coastal defence and management of habitat change should be placed. It states for West Kirbyand Hoylake; the coastal defence policy is ‘hold the line’ with selective management of natural defences ie. beaches and dunes.

The Issues
The amount of wind blown sand reaching the sea walls will continue to increase. Although this is not a new process, the significant difference is that the rate of wind blown sand reaching the upper shore is predicted to increase substantially over the next 5 to 15 years.

The existing management regime is unsustainable and the Metropolitan Borough of Wirral needs to urgently improve their beach and sand management policy:

Economic Sustainability
The £70,000 annual costs will increase, and are predicted to exceed £100,000 within 5 years. The quality of sand is of low economic value and it is also unlikely to be acceptable to English Nature to remove this material from the natural system. The cost of recycling sand within the system e.g. dune repair, needs to be balanced against the capital cost of works to protect the dunes from erosion

Coast Protection Issues
The rapid accretion of sand is of benefit to the natural and man made coastal defences along the entire study area. Higher shore levels absorb wave energy before it reaches the seawall, and natural defence lines such as sand dunes. The rate of sand accretion is predicted to more than keep place with predicted sea level rise. Some privately owned defences are in need of repair and mechanical removal of sand could potentially undermine the strength of these defences.

Flood Defence and Drainage
Surface water drains penetrate the embankments at West Kirby and Hoylake and flow onto the beach. The hydraulic gradient is sufficient for the water to drain through the sand for those that are periodically buried by increasing beach levels. If however the sand becomes more consolidated and muddier, there could be a surface water drainage issue that could cause problems with drainage of the highway. This situation needs to be monitored as provision for an interceptor surface water drain at both Hoylake and West Kirby may be required.

Of more immediate concern is the blocking of surface water gullies and drains on the highway from wind blown sand. This can create localised flooding of the highway and has serious financial implications for the local authority in the removal of sand. Clearly, this is one of the main drivers for the alleviation of the wind blown sand problem.

Highways and Transportation
The public safety issue due to sand on the highway is a key issue.Accumulating sand can create slippery conditions. Blocked gullies can cause localised flooding with consequent hazard and nuisance to all road users. With increasing beach levels the frequency of these events will increase if the current management regime is maintained.

Amenity and Recreation
The quality of the traditional seaside experience is predicted to change over the long term due to increasing beach levels, habitat change and especially the possible development of muddy areas and salt marsh. All of these changes will alter the character of the area from sand, sea and waves to sand dunes and saltmarsh with the waves and sea some distance offshore. Although perceived as undesirable by many, this is part of a long-term process of change that Metropolitan Borough of Wirral can manage but cannot stop. As part of this management Metropolitan Borough of Wirral needs to consider seascape and landscape impacts and any liability issues arising from structures placed on the foreshore. Standing pools of brackish water are attractive to the Seaside mosquito (Aedes detritus) that is known to breed on the Dee Estuary and cause a public nuisance. As part of any management policy it is recommended that a mosquito larvae management plan be developed. It may be possible to influence the direction of habitat change to favour sand dunes over mud and marsh; because this action will not try to stop the change, it has more chance of success.

Nature Conservation
The area is designated for its nature conservation importance and due consideration must be given to these national and international obligations in developing any proposals to manage wind blown sand. As a general principle the site managers are encouraged to work with the rate and direction of natural habitat change. It is inevitable that some habitats and species will deteriorate or be lost; although the loss of rare habitats and species can be managed in the short term, the principle of semi-natural succession, with perhaps the loss of valued species, should be accepted as a long-term policy.

There is a need for a policy that prioritises sand recycling for the maximum conservation benefit, assists coastal defence and alleviates wind blown sand problems. For instance, the current practice of dumping sand removed from the base of the embankment at West Kirby offshore and upwind in order to cut costs will simply result in that sand returning.

The present aproach is unsustainable as habitat succession is being retarded by beach cleaning and ploughing.

The Options
Before any action is proposed, all the major options need to be considered .ie. should we do anything? should we retreat, should we use ‘soft’ structures such as beaches, marshes and dunes to protect the coast, or should we build more ‘hard’ structures such as sea walls to defend our selves? 

Management Policy	Do nothing	Existing management policy	Retreat	Hold the line with selective habitat development to locally advance the soft line of defence.	Advance the soft defence line eg. encourage the seaward extension of sand dunes.	Advance the hard defence line eg. construction of new sea walls
Social sustainability	Not acceptable. Wind blown sand would overwhelm the built environment. Amenity value seriously affected.	Unacceptable as wind blown sand will continue to increase with greater costs and management intervention required.	Unacceptable as significant built environmentimmediately adjacent to coast.	Trials will establish acceptability More acceptable than all other options proposed	Trials will establish acceptability	Wooden groynes more acceptable than new seawall or raising of existing embankment.
Environmental sustainability	Acceptable purely from an environmental viewpoint as it lets nature take her course	Unacceptable as the policy conflicts the principle of working with coastal change	Detailed proposalswould need a significant environmental appraisal	Sustainable — working with natural coastal evolution and attempting to replace rare habitat previously lost in the Dee Estuary.	Sustainable — working with natural coastal evolution and attempting to replace rare habitat in the Dee Estuary	Unsustainable as it requires reclamation of Ramsar site Special Protection Area
Economic sustainability	Not acceptable. Major economic costs to business, highways, property value and relocation	Unacceptable as costs will continue to increase	Unacceptable due to cost.	Indications are that it is the most economically sustainable option in the long term though costs of trials and monitoring will be initially costly	Cost benefit analysis required butindications are that it is an economically sustainable option	Prohibitivelyexpensive and not justifiable in coastal defence terms.Rising beach levels will keep pace with sea level rise
Other issues of concern	Major impacts on recreation, tourism. Public healthissues from surface water drainage and storm water discharge	Commercial sale of sand discounted due to quality issues and concerns expressed by English Nature	Impact on tidal flows in the Estuary	Success of policy dependant ontrials, consultation process and results of monitoring	Success of policy dependant on trials, consultation process and results of monitoring.Concern over development of salt marsh and siltation	Result in major disruption to the physical processes in the Dee Estuary and along North Wirral.(wind blown sand issue would worsen due to accelerated wind speeds if seawalls raised)
Compatibility with Shoreline Management Plan Overall Assessment	Not compatible Rejected	Compatible with hold the line policy.Takes no account of process change. Rejected as an option of isolation.	Conflicts with SMP Rejected	In line with SMP policy. Accepted as part of a package of monitoring and trials	Longer term development of SMP policy. Accepted as part of a package monitoring trials.	Conflicts with SMP. Rejected.