Widewater Management Plan

Management Plan for Widewater Lagoon 2009 - 2014

1: VISION STATEMENT

2: INTRODUCTION TO MANAGEMENT PLAN

Widewater Lagoon has long been known as a site of high nature conservation importance, being the only known locality in the world for Ivell's Sea Anemone (now considered extinct), and a location for a number of other rare species adapted to the stressed conditions of shallow estuarine areas and coastal lagoons. The lagoon is also an important feature for local people, being enjoyed by many who visit to watch migratory birds, or by walkers, joggers and cyclists who visit this part of the sea front. It is also highly valued by people who live on its boundary.

The lagoon has suffered rather badly over recent years as a result of drought, and possibly for other reasons such as low water levels, bad-smells resulting-from the deoxygenated conditions, litter and the general appearance.

In 1991 Lancing Parish Council purchased the lagoon and agreed that action needed to be taken to restore it - primarily because of its importance for nature conservation. At the same time it was hoped that its value as a public amenity (in terms of its general appearance and condition) could be enhanced. For this reason, in 1993 a management plan for the site was commissioned, with funding provided by Adur District Council, West Sussex County Council, Natural England and the National Rivers Authority (Now the Environment Agency).

The management plan has not been able to answer all the questions about this site, its history and mechanisms for future management since some fundamental information was lacking, notably on the site's hydrology and hydrogeology. This management plan is, therefore, a first step towards solving Widewater's problems. The long-term future of the site lies in the hands of the authorities and other bodies, which have an interest in it, particularly Lancing Parish Council, Adur District Council, West Sussex County Council, Natural England and the National Rivers Authority (Now the Environment Agency).

West Sussex County Council commissioned a management plan review in 2000. Its aim was to update the 1993 Widewater Lagoon Management Plan (Everett 1993) in view of the progress made on the site and new information available since that plan was produced.

This review covered the period up to 2005 and was an extension of the 1993 plan and was designed to be used in tandem with that plan. This review will cover the period 2006 - 2012 with the plan becoming active in 2007. It rationalises the information in the previous two plans as well as updating the information and progress that has been made. It will utilise all the past and new information about Widewater to plot a path to the continued management of the site for the next 5 years.

3: GENERAL DESCRIPTION

Widewater is a shallow micro-tidal lagoon, which is about 1.1 km long and 30-40m wide, broadening to 80m at the eastern end. The total area of the lagoon basin (including shore and shingle habitats): is 7.65 hectares (18.9 acres), with the Open water (area as shown on the O.S. 1:2/500 - but this varies according to climate and season, being reduced in drought and dry periods) accounting for 4.69 hectares (11.59 acres). The area of the others habitats accounts for the rest of the site with the Vegetated shingle being 1.61 hectares (3.98 acres), Other habitats (saltmarsh, tall grassland and tall herbs, short grassland): 1.89 hectares (4.67 acres) and the Car parks: 0.83 hectares (2.05 acres]. Making the total area of site 8.62 hectares (21.3 acres) A footbridge crosses over the lagoon approximately halfway along its length, at a place where the width narrows to less than 10 m, effectively dividing the lagoon into eastern and western halves. The exact dimensions depend upon the volume of water contained at any one time; this can vary from week to week, season to season and from year to year. The Lagoon is completely isolated from the sea. The site is next to Lancing Beach and there is a large public car park adjacent to it, which fills up mainly with local visitors (from Lancing) when the weather is fine. It is not a key tourist locality but some people from out of the area do visit. Local people use it for dog walking and birdwatching, and the promenade area is popular for sightseeing/ cycling/ jogging and dog walking. Windsurfers also use the car park. Visitor surveys carried out by Lancing Parish Council in 1992/3 showed that the majority of visitors wished to see Widewater conserved as a natural resource.

Seawater enters and leaves via percolation through the seaward bank and through the bed of the lagoon. The lagoon basin (i.e. bank to bank) fills with water in 'normal' winters when the ground water table is high and there have been high tides to replenish it (Everett 1993). At times of low water (in summer) its depth varies from 5cm at the southern shore to 150cm in the deepest part, giving a mean depth of 80cm (McDonagh and Sheader 1991). The bottom of the lagoon is thought to be shingle, cased with clay. The latter could have been imported in the 19th century in an attempt to abate the intrusion of the sea (although no documentary evidence to substantiate this exists). The bottom of the lagoon is thought to be of shingle cased in clay, which is overlain by soft, black anaerobic mud. A core taken from Bristol University's borehole on the lagoon shore identified the following substrates (depth in order from surface): shingle (0-1.38m), stiff plastic clay (1.38-1.90m), sands (1.9-6.5m), gravels (6.5-15m), clay (15m-22.5m) overlying weathered chalk to the bottom of the borehole at 37m).

There is no natural direct connection with the sea, but in 2003 a pipe was installed through the shingle bank to the sea to enable water to be inputted in to the lagoon during drought periods. Freshwater input is derived from land run-off and precipitation. In August 1990, the salinity was measured as being between 44-50 ppt - markedly hyper saline. However, in July 1993 it was between 37-40ppt, more typical of values obtained in the 1970s and 1980s (Irving 1997).

The priority habitat is the saline lagoon, a rare and declining habitat both in Europe and in the UK, with associated aquatic fauna including lagoon 'specialists' which are adapted to the fluctuating environmental conditions of saline lagoons. However, some of the key lagoon plants and animals have disappeared over the past 60 years including Ivell's Sea Anemone. Widewater was the only known world location for it). Another globally rare species, the hydroid Clavopsella nauis still remains there. The lagoon shore also holds high quality vegetated shingle, a small saltmarsh plant community and tiny areas of maritime grassland. The site is of regional importance as a nesting site for Ringed Plover.

In recent summers the lagoon has been dominated by floating mats of the green alga Cladophora sp., but used to hold beds of Beaked Tasselweed Ruppia maritima, a species that would normally indicate a healthy lagoon. Other green algae (Chaetomorpha linum and Ulva) also used to be present in greater quantities but their abundance declined during the recent drought years (1989-90). The shingle has Sea Kale, Yellow-homed Poppy, Sea Campion and patches of grassland (Sea Couch, False-oat Grass, Thrift, etc.) interspersed with bare shingle used by breeding Ringed Plover Charadrius hiaticula. The shore has a narrow band of saltmarsh vegetation on its fringe and a bare unvegetated area, part of which is inundated at high tide by the rising water level in the lagoon. Tall grass and tall herbs with sparse scattered scrub present dominate the banks of the lagoon basin.

There have been notable changes to the lagoon and its biota over recent years, leading to concern over the continued survival of the site and its interest as a brackish-water lagoon. West Sussex County Council identified it as a Site of Nature Conservation Importance in 1992 and a Management Plan was drawn up for the site in 1993 by the Nature Conservation Bureau Ltd. (Everett 1993). In 1997 it was designated a Local Nature Reserve by West Sussex County Council. Lancing Parish Council owns the site.

In physical terms the site has changed very little over the past sixty years, with the exception that the water quality and its biological interest has declined. The primary reason for this is considered to be due to falling water levels resulting from hot summer temperatures and low summer rainfall associated with drought, particularly between 1989 and 1991. Other factors such as pollution and reduced permeability of the seaward barrier (due to leaching of fine particles in material dumped on this after the war) may be relevant, but are impossible to determine.

3.1: General Information

3.1.1: Location & Site Boundaries

Widewater lies-parallel to the coastline between South Lancing and Shoreham, West Sussex (see Map 1). The Lagoon forms a narrow stripe of water between the coastal shingle and the houses, which have been developed to the north. The Lagoon is bounded by a broad shingle bank on its southern boundary, approximately 150 m wide and 20 m high, upon which a concrete promenade and beach chalets have been built. The bank, which is a primary sea defence, lies at 6.2m O.D. A wooden slatted sea defence about 1.5m high has been recently erected on the beach side of the promenade and the beach itself has recently been regraded and groynes replaced to enhance the primary sea defence. A second shingle bank about 4.8m high, which is a secondary sea defence, runs along the northern boundary, upon which houses were built in the 1920s. Most of these properties have their back gardens extending to the water's edge and some jetties have been built out into the lagoon.

The seaward bank/sea defence is 6.2m O.D. with mean high water and mean low water normally ranging from 2.93m to -2.57 O.D. (spring tide ranges) and 1.73 to -1.37 (neap tide ranges) [source: Dobbie & Partners cross-sections through proposed beach replenishment, 1990]. Levelling done in the 1990s indicates that the bed of the lagoon lies at about 1.6m O.D., below the high tide ranges but nevertheless dangerously 'perched' above sea level for significant periods.

3.1.2: Tenure

Freehold owned by West Sussex County Council and is leased by Lancing Parish Council (except for a small comer at the eastern end which is owned by Colindale Properties Ltd., 67 South St., Lancing, W. Sussex). See Map 1.

3.1.3: Site infrastructure

Lancing Parish Council leases the site, with overall responsibility for the site being with the Parish Clerk. Management decisions are achieved through a Management Group with representatives from WSCC, Lancing Parish Council, Shoreham and District Ornithological Society and a Residents Group. The Coastal Plains Ranger (WSCC) is responsible for the surveying and monitoring activities on the site and any biodiversity projects. Lancing Parish Council (LPC) is responsible for hard and soft landscaping projects, which includes fencing and the car park. LPC are also responsible in maintaining the site in a presentable condition i.e. litter control.

3.1.4: Map coverage

OS 1:50,000 sheet no: 198

OS 1:25,000 sheet no; Pathfinder 1306 TQOO/10 Worthing & Littlehampton and

Pathfinder 1307 TQ20/30 Brighton

OS 1:10,000 sheet no: TQ 10 SE TQ 20 SW

See Map 1for OS base map, based on 1:2,500

3.1.5: Photographic coverage

Aerial photos

(i) Ref Nos 51/20NW and 51/20SW flown by the RAF

August 1947, held by West Sussex County Council

(ii) Ref no 70K GS 9-13 Shoreham-Atherington 29.10.86

held by Natural England (Oblique, flown by Cambridge University)

(iii) 8.11.90 held by Natural England (Oblique colour prints on

Widewater file)

Other photos

Older photos held by Mrs Walker of 186a Brighton

Road, and a 1936 painting of a bungalow and garden, which was

sited on the lagoon shore to the west of the Main Causeway.

Colour prints of entire site taken July 1993 by The Nature

Conservation Bureau Limited (to be given to Lancing Parish

Council)

Colour prints held by Natural England, taken 30.8.90.

3.1.6: Compartments

Cmp 1. The Saline Lagoon

Subcmp 1.1 The West End of the Saline Lagoon

Subcmp 1.2 The Central Section of Saline Lagoon

Subcmp 1.3 The East End of the Saline Lagoon

Cmp 2. The shingle and Marginal Vegetation

Subcmp 2.1 West end marginal grassland

Subcmp 2.2 The Vegetative Shingle

Subcmp 2.3 Central wet marginal grassland

Subcmp 2.4 The Shingle at the Eastern End

Subcmp 2.5 The car parks

3.2: Environmental information

3.2.1: Physical

The influence of the Sea

There has been bubbling observed from the base of the lagoon at normal high tides, indicating that some through flow of air and/or seawater occurs through the shingle bank and via the bed of the lagoon. The bubbling is localised and may reflect places were water or air is able to penetrate through the under lying strata. Upwelling of air/water also used to be particularly noticeable at the eastern end of the site before the bird island was built in the 1980s (pers. comm. F. Preston). It is possible that the construction of this island on that particular site was inappropriate and may have reduced one source of replenishment. Seepage has also been noted on the southern margin where a slight incoming flow of water may be observed immediately west of the Main Causeway.

It has also been reported that the lagoon fills up with spring tides and most particularly in rough weather when the sea breaks over the shingle bank/sea wall. Other observations (Sheader/various and Norton/Everett 1993) bear out the fact that the lagoon itself is tidal. Levels taken in the University of Bristol borehole on the south shore showed that the water level in the borehole rose by 2.5 metres between low and high tide on one date in June 1993 to within 50cm of the shingle surface (the normal tidal variation of the sea at Lancing is about 4m). However there are no data on levels within the lagoon itself and how these vary either with the tides or on a seasonal basis. It is also not known what affect the suspected clay casing of the lagoon bed has on either preventing/reducing seawater percolation into the lagoon or maintaining the lagoon levels (i.e. preventing seepage via the bed). Within the borehole the tidal influence was between 0.9m above and 1.6m below the clay zone. It is therefore quite probable that if there is a clay layer underlying the lagoon that it reduces the input of seawater, which would otherwise normally, occur without it, although some natural horizontal seepage through the overlying shingle probably occurs at high tide. It is also possible that the clay layer may be helping to keep water in the lagoon, which might otherwise drain away at low tide! The bed of the lagoon is higher than MLW, lying at about 1.6m O.D./ according to levelling done in 1990. This means that the Widewater is perched and it is not surprising that it only seems to fill up on high spring tides. (The bottom of the bed lies below mean high neap tides [1.73] and mean high springs [2.93] but well above low tides [neap: -1.37, spring -2.57]).

There are, in effect, two sea defences, the seaward shingle bank (primary sea defence) with The Promenade and chalets, and the northern bank (secondary sea defence) upon which the Brighton Road’ houses were built. The seaward bank was probably a lower natural shingle spit or beach crest before it was 'improved' to secure the sea defences, although test borings into the bank have found concrete 75 feet below its current crest (pers. comm. F. Preston, NRA) - this concrete may be several hundred years old - the area has a history of 'havoc wrought by the sea' and there must have been very early attempts to prevent further erosion and destruction of settlements to the east by the sea (and it is believed that a crude type of concrete was used during the time of the

Armada). The landward bank is a secondary sea defence and was thought to have been built by Dutch engineers in the 19th century (anecdotal evidence from Widewater residents). It is shown on the 2nd edition OS map of 1898. During the war/ large concrete blocks about one metre high were erected along the top of the sea wall as a defence against German tanks. After the war these were not removed, but the bank was built up over them using 'lorry loads of black slack' (pers. comm. Mrs Walker) and refuse (pers. comm. Frank Preston, NRA) and the concrete walkway along the top of the bank was built. In 1990 a new wooden timber storm fence was built on the crest of the bank, the shingle beach was regraded and new groynes constructed along the beach. These activities may have (a) reduced the rate of percolation of seawater through the seaward shingle bank, and (b) reduced the number of 'overtopping' incidents (i.e. the number of times the bank has been overtopped by the sea in storms). Fine particulate matter leached out of the 'slack' and rubbish could well have acted to reduce the permeability of the underlying shingle bank.

Overtopping incidents are considered important for replenishing the lagoon. However, storm tides today are around four feet or higher than they were at the turn of the century and since 1985 there have been increasing problems with higher tides (pers. comm. Frank Preston, NRA)- The sea wall was almost breached in 1989/90.

There has been some concern over recent years that beach defence works may have affected the percolation of water through the shingle bank. Certainly, the construction of groynes has involved driving long planks into the beach. Piles have also been driven into the sea wall/shingle bank but it is unlikely that these have been driven down so far as to prevent percolation. There is no data on the rate of percolation through the shingle bank, or on the water gradient from the sea through it to the Widewater (and vice-versa).

The lagoon's hydrology is considered to be dominated by

[1]: sources of incoming water - (a) seawater percolation through the shingle bank replenishment when storms cause the sea to overtop the bank, (b) surface water runoff and the pipe

[2]: water loss via evaporation and percolation through the shingle bank (and lagoon bed).

Land north of the Brighton Road lies below the Brighton Road (which itself is only 2.1m O.D.). The housing estate (Hasler Estate) here use to regularly flood as a direct result of high and storm tides which overtopped the sea wall, with the water making its way out to the Brighton Road and beyond due to seepage through the north bank (pers. comm. Frank Preston, NRA). This flooding problem has now been dealt with by the recent installation of better surface drainage on the estate. Towards the railway line, 1km to the north the ground level falls to 1.2m lower than the average high tide and lower than the bed of the lagoon. A major drain to the north is lower than Widewater. The movement of water is therefore predominately away with landward groundwater tables not playing a role in the lagoon's hydrology.

Surface water recharge from the landward side

There is some surface recharge from the landward (north) side - a number of the houses, which back on to the Lagoon, have routed their roof drains out to the lagoon (via their gardens). There is also likely to be some surface water runoff from those properties, whose gardens slope down to the lagoon. There is no known surface water discharge from the Brighton Road into the lagoon (letter from Area Highways Engineer, West Sussex County Council 1992). The catchment area for surface water drainage is therefore restricted to the properties, which immediately adjoin the lagoon, and to the shores and banks of the lagoon itself.

Rainfall

This, with run-off, is considered a major source of freshwater recharge (Sheader and Sheader 1990).

Other sources of freshwater

A number of anecdotal reports were received to the effect that there used to be a freshwater inlet at the western end of the lagoon.

3.2.2 Water chemistry

Salinity

The salinity can fluctuate from a winter low of about 25 to 30 parts per thousand (ppt) to a summer maximum of 35 to 40 ppt. Nossier (1980) considered that the normal salinity range for Widewater was 30-38ppt. (The normal salinity of seawater is c.34-36ppt). However, in 1990 (30 August) salinity reached 50ppt with a small area of lower salinity (44ppt) at the extreme western end. At the time of this survey by McDonagh and Sheader there was very little water in the lagoon, with water only retained in the deep channel, which lies 10m from the northern shore. Most of the lagoon was exposed as a dry-cracked mud surface. In the central channel the water depth was 10-15cm (maximum 30-40cm) with the width of the lagoon reduced to around 7-15m for most of its length.

In contrast, on 13 September 1990 (following high equinoctial spring tides) salinity was 45ppt as a result of dilution by seawater percolating through the shingle bank. The lagoon was 5cm deeper and the wet area l-3m wider.

In July 1993 recorded salinities varied from 37-40ppt. These are considered 'slightly elevated' but not likely to impose a significant physiological stress on the resident aquatic flora and fauna' (Sheader and Hawkins 1993).

Percolation through the shingle barrier at Widewater is inadequate to prevent serious reductions in water levels and large increases in salinity as a result of drought, has occurred between 1989 and 1991. In many other south coast lagoons, it is the regular input (and outflow) of seawater, which helps to counteract the loss of water and high salinities.

Oxygen, pH, nutrients and heavy metals

In 1993 the ranges of the major nutrient concentrations were the same as those reported for other saline lagoons and static marine waters, being low. These low nutrient concentrations are a consequence of summer primary production in a closed system and it would appear that phosphates are likely to be a limiting factor in plant growth at all but one of the five sites sampled by Sheader and Hawkins.

The pH (8.3-8.6), temperature (20.5-21.5°C) and oxygen (6.5 9.0mg/l-1) concentrations recorded in July 1993 by Sheader and Hawkins are comparable with those previously recorded in 1983 and with those prevailing in northern European shallow sheltered coastal waters and estuaries.

Pesticides and other pollutants

Sheader and Hawkins (1993) sampled sediment concentrations of cadmium, copper and zinc at five locations along the bed of the lagoon and considered that the levels they recorded in the sediment were comparable with those reported for estuarine sediments subject to industrial inputs. They considered this as 'moderate' pollution but thought that the large amounts of organic matter and clay in the sediment were likely to chelate and bind significant amounts of metal cations, hence reducing the likely 'bioavailable' concentrations of these metals in the water.

The heavy metal concentrations in the water were considered comparable with those reported for northern European coastal waters by Burton and Liss (1976) and so probably reflects the local burden of the adjacent seawater. Probable sources of heavy metals may include;

(a) Sewage (from nearby sea outfalls and percolation through the shingle bank in dilution with seawater)

(b) Refuse and the black 'slack' (which could have been waste from an industrial process or coal waste) dumped post-war to build up the sea defence.

(c) Dumping (e.g. of old paint tins, etc). In such a small, enclosed, ecosystem, even minute amounts of oil, paint and other contaminants may have a lethal affect on algae and aquatic species.

(d) Runoff from gardens may be another source of pollution (i.e. from garden pesticides) but there’s no qualitative or quantitative data on this. However, the overall levels of pesticides are likely to be extremely small. There are no records that pesticides have been applied to the lagoon and its shore (i.e. to kill algae or flies) (pers. comm. R. Lord, Adur District Council, 1993). Dog fouling is a problem along the lagoon shore, which may lead to the enrichment of surrounding habitat and may lead to the lost of biodiversity to the vegetative shingle.

3.2.3: Hydrology of Lagoon

The influence of the Sea

The lagoon's hydrology is considered to be dominated by

[1]: sources of incoming water - (a) seawater percolation through the shingle bank replenishment when storms cause the sea to overtop the bank, (b) surface water runoff and the pipe

[2]: water loss via evaporation and percolation through the shingle bank (and lagoon bed).

Surface water recharge from the landward side

Rainfall

This, with run-off, is considered a major source of freshwater recharge (Sheader and Sheader 1990).

Other sources of freshwater

A number of anecdotal reports were received to the effect that there used to be a freshwater inlet at the western end of the lagoon.

3.2.3: Biological

3.2.3.1: Habitats/communities

The Saline Lagoon

This habitat is an extremely harsh and specialised ecosystem. It is dominated by the extremes of salinity, water temperature and fluctuating water levels, which regularly leave the fine or medium sediments exposed to the atmosphere. This ecosystem is only inhabited by fauna and flora that can tolerate extreme conditions (extremophiles), with many of the specialist inhabiting the fine sediments on the bottom. These sediments are offering anoxic conditions within l-2mm of the sediment surface. Most lagoonal animals are able to tolerate these and the very wide ranges of other environmental parameters characteristic of lagoons: variations in temperature, oxygen and salinity within limits. Due to the extreme conditions this habitat is characterised by a low but extremely important biodiversity.

There are three main aquatic habitats in the lagoon: the sediment, the water body, and weed. Faunal surveys carried out between 1978 and 1993 have concentrated on the sediment and invertebrates. A full species list is recorded in Appendix 5

Terrestrial habitats

The following description of terrestrial habitats is taken from a survey of the site carried out in 1993 by John Norton of The Nature Conservation Bureau Limited. A full list of species recorded in the 1993 survey and on previous occasions may be found at Annex 2.

The lagoon consists of terrestrial 'zones' as follows:

1. Embankment

2. Lagoon shore

a. Shingle

b. Grassland (including Sea Couch saltmarsh)

c. Inundation communities (saltmarsh)

d. Bare ground (including tidal zone and dry unvegetated

ground, which is periodically inundated)

3. Islands

Embankment

A steep bank drops down some 3-4 metres from the promenade (which is situated on the top of the sea wall). This is largely vegetated with 'tall herbs' and tall grasses (mostly False Oat-grass) growing between 0.5m to 1m tall with a few scattered bushes of Bramble, Elder, English Elm, Hawthorn and other shrubs. Typical plants are Lesser Burdock, False Oat-grass, Creeping Bent, Perennial Rye Grass, Red Fescue, Mugwort, Michaelmas Daisy, Common Orache, Hedge Bindweed, Sea Beet, Thistles, Sea Couch, Common Mallow, Hawkweed Oxtongue, Bramble (in patches) and Ragwort. Alexanders is locally abundant. The 'weediest' areas are along the eastern part of the site, particularly where there has had localised dumping of soil - adding to the general disturbance and attractiveness of the site to large 'weeds' such as thistles and ragwort. To the west of Main Causeway the embankment is generally much less weedy, with grasses predominating, and there is a wide flat grassy zone running beside the concrete path and to the top of the bank.

Lagoon shore

This can be subdivided as follows:

Shingle

It is presumed that the shingle is gradually accumulating as a result of winter storms and shingle being dropped over the bank in high seas. The results of the borehole coring would appear to confirm this (1.4 metres depth of shingle and sand had accumulated over the clay liner which was laid on the bed of the lagoon in the 19th century.) Shingle zones are mainly confined below the embankment and to the zone of inundation west of the main causeway. Much of the shingle is bare of vegetation, but in places it holds a typical 'vegetated shingle' flora or short grass and short herb plant community. In some places the shingle is 'pure' (i.e. typically of large rounded pebbles such as those found on the adjacent beach. This shingle supports a high quality shingle flora with species such as Sea Kale and Yellow Homed Poppy, interspersed with Sea Campion, Ivy-leaved Toadflax, Rock Samphire, Biting Stonecrop and White Stonecrop. In these areas the shingle is only sparsely vegetated and interspersed with larger bare areas. This habitat is highly suitable for nesting Ringed Plover.

Small areas of the shingle are rather more vegetated, having 100 % plant cover. Sometimes this is in the form of short herb communities, typically of clovers (Trifolium spp), Buck's-horn Plantain, stonecrops, and moss. Other patches of vegetated shingle hold stands of False Oat-grass, Sticky Groundsel, Sea Beet/ Common Toadflax, Coltsfoot and Sea Mayweed. Bramble has colonised in a few places but has nowhere taken a firm hold. Kidney Vetch and Thrift are also present but scarce.

These vegetated shingle areas often appeared to be segregated into two different communities, in several places showing a clear zonation. On the lower shore there are clearly two different bands of vegetation below the Sea Kale community and the dense green of the Annual Sea-blite growing on the muddy shore. The first of these is a band of vegetation consisting of Sea Beet, the second is characterised by abundant Sea Mayweed and Sticky Groundsel, with other species such as Spear-leaved Orache. The latter community occurs as a narrow band for the entire length of the shingle area, and also around the shingle island.

The range of relatively undisturbed shingle communities, from mature completely vegetated shingle to bare shingle, is quite unusual in South-east England.

Grassland and Sea Couch

There are several different grassland types: medium-tall grassland (30-50cm) of False Oat-grass and/or Sea Couch, tall grassland with Red Fescue, and short grassland with Buck's-horn Plantain and Thrift. The latter is highly attractive, with the pink thrift flowers in bloom from early May into the autumn. The largest area of this 'Thrift' grassland appears to be maintained by trampling - being sited adjacent to one of the car parks it is used for informal picnicking, sunbathing and other similar activities!

Sea Couch is dominant over parts of the south shore at the eastern end and also occurs as a strip at the base of the low bank in section 4. Other species recorded in these areas were Thrift and Buck's-horn Plantain as well as tall herb species such as Hairy Willowherb, Teasel and Smooth Sow-thistle.

These areas of tall grassland and patches of grass on the shingle shore look as if they may be attractive to invertebrates, particularly bush-crickets and grasshoppers, although no nationally uncommon species have been recorded.

Inundation communities: saltmarsh

This is a narrow area along the shore of the lagoon, which is regularly inundated and holds small areas of saltmarsh plants. The most recently exposed zone around the lagoon margins may be defined as annual salt marsh, which had a sparse to almost complete (10-90) vegetation cover when surveyed in 1993. Abundant and locally dominant plants are Annual Sea-blite, Glasswort and Lesser Sea-spurrey. Sea Aster, Spear-leaved Orache and Groundsel are also recorded. Further away from the water margin, other species are present, including Sea Couch and Hard Grass while Sea Aster is more frequent. (The best stand of Aster is along the base of the houses at the far western end of the lagoon.) A few small areas of 'established saltmarsh' were also present mainly in the muddy basins immediately to the west of Main Causeway (section 2 on the vegetation map, Appendix 4). These were typically (a) Sea Purslane (one stand) (b) Saltmarsh Rush and (c) stands of Hard Grass (Sea Milkwort and Sea Arrowgrass present but rare here). The lower saltmarsh zones are subject to tidal influences and daily inundation by saline water.

Bare ground

Inundated during normal winters when water levels fill the basin, the bare ground represents the bed of the lagoon, which has dried out due to evaporation in the summer months. During drought years this zone will take up a correspondingly larger area. Shells of bivalves are locally abundant here, indicating widespread mortality of species such as Lagoon Cockle during periods of low water. Damp bare mud also occurs on the tidal edge of the lagoon between the water and the lower saltmarsh zone.

Islands

The easternmost island was constructed in the 1980s. Details of its construction are documented in the report by Adur District Council (1982). It was constructed to provide a safe roosting and breeding area for birds, but may have disrupted one major source of seawater recharge into the lagoon. A number of other islands of varying ages are present elsewhere in the lagoon. Most of them are of a scruffy appearance with dilapidated timber revetments, which need to be removed and Tamarisks, which could do with pruning back.

3.2.3.2: Flora

In the 1970s and early 1980s, Chaetomorpha dominated, to such an extent that local residents removed large amounts annually. The macroalga Chaetomorpha linum is thought to contribute significant amounts of organic matter to the bottom-dwelling animals upon its decay (Sheader and Sheader 1990). C. linum was the dominant macrophyte until 1985, forming dense mats covering up to 70 of the water surface. This is also the dominant alga in many other south coast lagoons and normally supports a diverse fauna. An abrupt change in the relative abundance of macrophytes occurred between 1983 and 1987. In 1990, floating mats of Chaetomorpha almost disappeared, though some were observed attached to hard surfaces within the lagoon. After 1987 a short period with very little macroalgae was observed. This was followed by the appearance of floating and attached mats of Cladophora, which dominated the lagoon and an increase in Enteromorpha. Chaetomorpha often supports a rich fauna, and lagoons in which Chaetomorpha and Ruppia dominates the macrophyte flora are amongst the richest in the UK. The dense Cladophora mats, which were present in the drought years are composed, have closely tangled filamentous threads, which form thick, soft mats over the sediments. The waters below the mats therefore become anoxic (devoid of oxygen).

This year has seen the reappearance of another species of green alga Ulva lactuca, and more interestingly the reappearance of Beaked Tasselweed Ruppia marina last recorded in 1931. However, this vascular plant (locally known as 'eelgrass') used to be abundant in the lagoon to the extent that the oars of boats would become entangled in it (pers. comm. Mrs Walker).

3.2.3.3: Fauna

Birds

Most of the following account is extracted from a report by Dave Smith, Recorder, Shoreham District Ornithological Society (December 1992). B. Forbes of SDOS provided information on Ringed Plover in September 1993.

The Widewater is one of a few areas of standing water in the recording area of the Shoreham and District Ornithological Society and is a popular haunt for birdwatchers.

Widewater is locally known for its passage migrant waders and passerines in spring and autumn (with autumn being the most interesting passage period), for its wintering wildfowl and waders, and as one of the few breeding sites between Brighton and Worthing for Ringed Plovers. For all these birds it provides food and shelter, either as a stop-off point on migration, or for longer periods in the winter months. Due to its size and disturbance it will never attract international or national bird numbers, but it is very important at a local level.

Breeding birds

Waders: This is one of the few breeding localities for Ringed Plover along the South Coast shingle. Up to seven pairs may attempt to breed, with two or three pairs more usually nesting on bare shingle to the west of the main causeway. During the years 1991 and 1992, 3-5 pairs bred but with little success. In 1993, 7 pairs held territory in the spring but had little success due to heavy predation by crows and severe disturbance by dogs and humans. Widewater is the only area with more than one pair attempting to breed between Rye Harbour to the east and Pagham/Chichester Harbour in the west. Both the latter sites also suffer from predation.

With its locality close to the sea it is regular used by Oystercatcher's, Turnstone and Redshank. Although water levels are managed to ensure the conditions are correct for the important Lagoon invertebrate communities. However the lagoon still attracts a number of passage waders including Green, Common and occasionally Wood Sandpipers. It has also attracted the odd rarity including Kentish Plover and Baird's Sandpiper.

During the winter period from about 2007 Water Rail has regularly used the site using the area of Tamarisk on the edge of the Lagoon.

Wildfowl: Two pairs of Mute Swan now regularly breed on the Lagoon taking advantage of the main island, which was constructed, at the eastern end of the lagoon in the 1980s. During the winter period the lagoon attracts a variety of waterfowl with regular visits from Little Grebe, Great Crested Grebe and Red Breasted Merganser. Occasionally some more unusual species turn up such as Long Tailed Duck taking advantage of the sheltered location.

Passerines: The location of the site also makes it ideal for passerines to visit generally on passage with species such as Wheatear, Reed and Sedge Warbler regularly reported taking advantage of the ideal conditions within the urban coastal strip. Others arrive to winter on the site with a Black Redstart now making regular appearances.

Fish

Two fish species have been recorded from the lagoon: Eel Anguilla anguilla and Three-spined 'Stickleback Gasterosteus aculeatus. Eels used to be abundant in the lagoon to the extent where they were trapped and taken to the local markets (pers. comm. Mrs Walker). They were last observed in large numbers in the 1970s. Small numbers were also observed in the early 1980s but not since. The sticklebacks declined during the drought years but must have persisted in small numbers.

Lagoon Specialist Invertebrates

Species of particular importance at Widewater are:

Ivell's Sea Anemone(Edwardsia ivelli) -

At its only known world location. Last seen in

1983 this globally threatened species, protected

under Schedule 5 of the Wildlife and Countryside

Act 1981, may now be extinct.

A hydroid(Clavopsella navis)

At its only known UK location. This species is

regarded as nationally and internationally rare and

is also protected under Schedule 5. It has been

recorded at Widewater as recently as 1997 but at

very low population levels.

Lagoon sand shrimp(Gammarus insemihilis) -

This RDB, Schedule 5 species has been recorded

at Widewater but may now be extinct from the

site.

The fauna of the lagoon was substantially more diverse in 1931 than after 1985 (Sheader and Sheader 1990). Species lost from the lagoon between this period include Ivell's Sea Anemone Edwardsia ivelli, for which Widewater was the only known world site, and a number of other lagoon 'specialists'. Between 1931 and 1990 the total non-insect invertebrate species list almost halved, with a steady fall to 1987 (but a slight recovery in species richness in 1990 (Sheader and Sheader 1990). In 1990 the dominant bottom living animals (benthic macrofauna) were the gastropod molluscs and chironomidae, which accounted for 42 of the 57 species and 99% of the lagoons biomass. Other species were present in very low numbers.

However a number of species have shown remarkable tolerance to the extreme conditions experienced in the lagoon. For example, in 1990, although the Lagoon Cockle Cerastoderma glaucum was still abundant, most of the specimens collected were weed-associated juveniles, indicating this species seems to behave as an annual in stressed situations.

These noticeable changes in the lagoon and its biota over recent years have been documented (Ward 1983, Sheader and Sheader 1985, Schleifer 1988, McDonagh and Sheader 1991, Sheader and

Hawkins 1993). The number of organisms in lagoons fluctuates on a seasonal basis in response to changes in patterns of reproduction and mortality. Between-year changes are dependent on a range of factors, including food supply and environmental stress. Most of the changes that have occurred in Widewater are considered to be the result of extreme fluctuations in environmental variables, notably salinity and the reduction in the area of open water. All lagoon species are able to withstand a degree of variability but in extreme conditions, as have been experienced in recent drought years, certain species are inevitably lost.

The numbers of macro-invertebrate fauna fell dramatically between 1987 and 1990, with a series of hot summers, low rainfall and high summer salinity. Up to 1990, when salinity values rose to around 50ppt, summer salinities reached around 38-39ppt. Lagoons are naturally high stress environments, often exhibiting marked diurnal, seasonal and long-term changes. Current theory would suggest that very high stress/disturbance levels would result in a decline in faunal abundance, whereas moderate stress/disturbance would result in high abundance (compared to an 'undisturbed' site). The 'normal' position of the lagoon community on the stress gradient is difficult to assess. The species composition is influenced by patterns of immigration and extinction, and in many ways the lagoon is comparable with an island. The fauna contains a marine/estuarine element of species typical of sheltered coastal or estuarine sediments, an insect element, comprising salt-tolerant species with flying adult stages, and a lagoonal element of species typically found in lagoons and lagoon-like environments. The number of lagoon species has declined since 1931.

Suitable sources of lagoon species may be some distance from Widewater, and chances of (re) colonisation are low. Sources of other suitable marine/brackish species may be closer (e.g. the Adur estuary), and for these species, the chance of (re) colonisation will be greater. The number of species has shown an increase since 1987, suggesting a return to the seemingly healthier conditions at the site in the 1970s. However, species composition has changed. Edwardsia Ivelli, a species of anemone known from only this site has become extinct. Recent losses from

Widewater include the bivalve Abra tennis, the lugworm Arenicola marina, the lagoon periwinkle Littorina saxatilis var. teliebrosa, and the isopod crustacean Idotea chelipes. The former two species seem to have succumbed to the combined effects of reduced substrate area, high salinity and increased sediment anoxia, whereas the latter two species thrived in the abundant floating mats of Chaetomorpha linum, which have declined in recent years.

In 1993 there has also been an input of new animal species to the lagoon. The crustacean amphipods, Melita palmata, Gammarus finmarchicus and Palaeinonetes varians have recently appeared the former two species never having been previously recorded at Widewater, and the latter having been absent since 1931. All three are common estuarine/intertidal species. The processes involved in a species successfully colonising an enclosed lagoon such as Widewater are no doubt varied (e.g. transport on birds' plumage/feet, transfer by overtopping of the seawall by seawater during storms), and the relative importance of such mechanisms is difficult to determine.

Other species are worthy of mention. The lagoon cockle Cerastoderma glaucum still maintains a sizeable population at the site. The hydroid Clavopsella navis continues to survive here, one of only three sites where it has been recorded in the world (but now extinct at one of them). The ostracod (Cyprideis torosa) first recorded in 1990, was still present in large numbers in the 1993 survey.

Survey and research summary

Botanical survey and lists 1993 1994, 1995, 1998 by J, Knight and G & B. Bishop

• Casual records of other groups G & B. Bishop 1993-5

• Annual monitoring of Ringed Plover breeding attempts by Shoreham District Ornithological Society

• Water level records from fixed gauge board March 1995 - present, recorded by L. Howard of FOWL

• WWT-UK Survey of Widewater Lagoon, Lancing, West Sussex. 16/17 September 1997, R. A. Irving

• Characteristics of Physio-chemical Water Parameters and Circulation Patterns in the Lagoon

Research in the invertebrates carried out by Brighton University 2001-2005

3.2.4: Cultural

3.2.4.1: Archaeology

Evolution of the Widewater

Widewater was believed by many to have formerly been tributary to the River Adur, which was cut off during the 18^th century as a result of natural movement of coastal shingle.

However, map and anecdotal evidence studied during the preparation of the 1993 management plan would indicate that it could be an artificial lagoon ('borrow pit'), which was dug out in the 19th century by a firm of Dutch engineers for the purposes of building a landward sea defence prior to building and drainage of marshland to the north. At the same time/or at a later date in the 19th century, it was thought the bottom of the lagoon could have been lined with clay.

The First Edition Ordnance Survey map of 1813 shows no lagoon but a tidal ditch or stream, which fed into a tributary of the River Adur below New Salts to the northeast. A map of 1780 does not show the lagoon either - only saltmarsh and ditches. However, the map evidence examined for the 1993 plan was inconclusive. From aerial photos, the lagoon gives the impression that it could be of natural origin and it is possible that it was subsequently modified in the 19th century.

The fact that a lagoon is not shown on maps of either 1780 or 1813 would indicate that the 'borrow-pit' theory is highly plausible. However, maps show that there was estuarine marsh on the site until around the early 19th century when brackish and estuarine conditions would have predominated.

Shieifer (1988) also attempted to piece together a history of the lagoon as follows: "The geomorphological history of Widewater is poorly documented. It seems that around the year 1085 the areas now known as Widewater, the New and Old Salts Farms, and Shoreham airport were part of the Adur Estuary. By 1250, eastward longshore drift of shingle had resulted in the formation of a spit separating the western part of the estuary from the sea. Sedimentation processes in the Adur consolidated land around the spit to the extent that a village called Pende was built on it. However, between 1500 and 1600 this land was reduced to tidal marsh and much of it was washed away, including Pende (Green 1877). By 1622 land reclamation referred to as 'inning' had been carried out resulting in an estate now called Old Salts Farm. This left a stream flowing parallel to the shore from the Sompting area and joining the River Adur at Shoreham. Sir William Goring affected more reclamation and by 1684 this stream had probably been cut off from the west (Kerridge 1979). Around 1700, Adams (1981) reports that continuous gales deflected the Adur eastwards. Widewater was therefore probably formed when the stream, which once flowed from the west, was cut off from the Adur by shingle and debris moved by the gales, and its original flora and fauna were probably very similar to that of the Adur estuary around 1700.

McDonagh and Sheader (1991) reported that a map dated 1780 shows no lagoon, but only a few small streams entering a marshy area. A second map, also dated 1780 shows a small lagoon to the west of the present lagoon site towards Lancing Beach. This is called 'Old Salts' on the 1795 map of the area. The first edition O.S. map, dated 1813, depicts an inlet from the mouth of the Adur estuary, again called 'Old Salts', but no lagoon.

In an account of the history of Shoreham, Adams (1981) reported that there was originally a connection between Widewater and the mouth of the River Adur, which was closed in the seventeenth century by continuous gales directing the river's course eastwards to Hove.

Another theory that it is a natural shingle spit lagoon formed by shingle movements and the development of a shingle spit in front of a former shingle beach. The bottom of the lagoon was lined with clay in the 19th century in an attempt to convert the lagoon to a freshwater lake. There were undoubtedly substantial movements of shingle in this area and these are referred to in historical texts (e.g. Cheat 1921). Cheat documents large-scale movements of shingle in the area from the late 16th century, which resulted in the development of a shingle spit, which formed across the mouth of the Adur. Before this, the coastline was thought to have extended considerably further south and without the protection of a shingle barrier or promontory was subject to flooding and erosion, to the extent that a substantial part of the old town of Shoreham was washed away in the Middle Ages.

Sea defence work

The sea wall and the north bank are thought to have been built by Dutch engineers in the 19^th century (pers. comm. Mrs Walker). The sea wall was substantially lower than it is now. During the war, large concrete blocks about one metre high were erected along the top of the shingle bank as a defence against German tanks. After the war these were not removed, but the bank was built up over them using 'lorry loads of slack' (probably shale or coal waste?) and all sorts of rubbish, and the concrete walkway along the top of the bank was built. Since then the sea wall has probably remained about the same height. In 1990 a new wooden timber storm fence was built on the crest of the bank and some 2km of beach in the Kings Walk and Widewater area was replenished with shingle, using existing beach shingle extracted from the vicinity of the NRA beach near the harbour, together with some supplementary imported material (in letter from Dobbie and Partners Consulting Engineers to Nature Conservancy Council). At the same time the extensive groyne system along the beach was renewed (and groyne works in the area are still ongoing).

3.2.4.2: Past land use

In the late 19^th early 20^th centuries 'Bungalow Town' was constructed on the shingle spit extending between Lancing and Shoreham. This comprised a motley array of bungalows, some of a temporary fabric (e.g. old railway carriages), others rather more permanent. A film studio was also built. All these buildings were demolished at the commencement of the 2nd world war so that tank and other defences could be constructed.

The sequence of developments continued through the 20th century:

1920 Brighton Road houses built on north bank

1931 Hasler Estate north of the Brighton Road built.

1939 “Bungalow Town” destroyed by the army and tank defences erected on the sea wall.

1945 Refuse and other material dumped on the sea wall to heighten it. Promenade constructed.

1963 Plans for various amenity developments drawn for tennis courts, pitch and putt course, playground, extended car park, tea gardens and lawns on land between the sea wall and lagoon (the development proposals covered the shore of the lagoon, including the saltmarsh and shingle). In the event, only the extended car park was built.

1970 Lancing sailing clubhouse constructed on the West Beach adjacent to the Widewater.

1966-1971 A marina project was proposed, but not submitted as a formal planning application due to the unsuitability of the scheme for the site. The scheme progressed to the stage of a draft heads of agreement being drawn up between Lancing Parish Council and the development company for the development of the area to be leased for 'the mooring of small sailing and motorcraft, the provision of toilet facilities, a tea garden and a chandlers shop, including the provision of a means for boats to obtain access to the sea'.

1972 Central causeway constructed: base of unrolled fill (brick and concrete rubble), topping of rolled fill and asphalt). c.1991 large house at eastern end of lagoon demolished and 4 new houses built. (An original application was for infilling of the eastern end of the lagoon and housing development on that as well as the bank.)

1989/90 Planning appeal and public inquiry over residential development scheme on land to the north (between Old Salts Farm Road and New Salts Farm Road). Appeal lost (the land is very low lying and liable to flooding). c.1991 Improved surface drainage installed on the Hasler Estate to the north.

3.2.4.3: Present land use

The area is a Local Nature Reserve designated specifically for the Saline Lagoon Habitat that is threatened on a European scale. the main interest is the communities of specialist invertebrates which inhabitats the Lagoon. The site is primarily as a conservation site and is used extensively by local universities for a number of studies and occasional school groups. The site is an important area from recreation and is extensively used by the local community for a variety of activities from walking dogs to birdwatching.

3.2.4.4: Factors Influencing Management

Natural trends

Climate

The cyclical nature of the climate is having, and has had, a significant impact on the integrity of the Widewater. In particular, the drought of 1989-91 resulted in the almost complete drying out of the lagoon, with the consequent loss of some of its characteristic animals and the mortality of many individuals. Additionally, the plant communities of the Widewater have also changed. In recent years Cladophora has largely replaced the dominant alga Chaetomorpha linum and the dense algal blooms in the shallow water have resulted in deoxygenated conditions, further contributing to the overall decline in the quality of the site. Beaked Tasselweed Ruppia maritima completely disappeared until 1993 when one plant was observed.

Although lagoon ecosystems are adapted to fluctuating water levels and its ancillary effects (e.g. temporary changes in salinity, widely fluctuating temperature and oxygen levels) the effects of the drought in 1989-1991 were visually devastating and equally damaging to the lagoon's flora and fauna. Previous periods of drought (e.g. around 1976) may have also contributed to the loss of some of the faunal species, but this is not known - the lack of information on flora and fauna between 1931 and 1978 means that the reasons for, or the timing of, changes in the fauna during this period cannot be determined.

Of course, drought is likely to have affected Widewater on many occasions in the past. For example, the level of the lagoon was extremely low in the 1940s (pers comm. Mrs Walker) to the extent that men could walk across it from the houses to the beach.

Another natural factor related to climate, which affects the lagoon levels, and, consequently, the water quality is the number and intensity of storms. Replenishment by seawater during high seas (i.e. the sea overtopping the sea defence and entering the lagoon) is known to be important. In fact this, rainfall and surface water runoff, and the percolation of the sea through the shingle bank at high spring tides are considered to be the most important methods of replenishment of water into the lagoon. Overtopping of the bank by the sea is also the most likely source of species, either to replenish populations already in the lagoon, or as a source of new colonists. Anticipated rise in sea level and storminess associated with climate change will have implications for the lagoon.

The lagoon is already showing some signs of biological recovery and given 'normal' rainfall years and sufficient high tides, it should have the ability for significant recovery (but not recovery of lost species without help). However, the lagoon does need to be protected from future droughts, both to conserve its biological diversity and to maintain its amenity value. Natural succession and the vegetated shingle

The most valuable (for nature conservation) terrestrial habitat associated with the lagoon/ is the shingle. This holds a high quality flora of species such as Sea Kale and Yellow-horned Poppy. The bare shingle is also important for nesting Ringed Plover.

Over time, vegetated shingle habitats may be stabilised by vegetation and organic matter may build up, promoting the colonisation of vegetated areas by taller species and bramble. In an exposed -beach situation, this is not normally a problem if the substratum is constantly being replenished by new shingle resulting from longshore drift and deposition during storms.

Furthermore, the exposure and salt spray also help to preclude rapid natural succession at such localities. However the shore of Widewater lagoon is quite sheltered. In years when water levels are high the shingle may be completely inundated with saline water again helping to prevent long-term natural succession. Undoubtedly seas overtopping the sea defence and depositing material on the lagoon shore also replenish the shingle from time to time. Bristol University's borehole proves the point: 1.4 metres of shingle and sand overlays a clay layer which may have been laid over the bed of the lagoon in the 19th century. In essence, the rate of natural succession and changes in the shingle flora need to be monitored over time, and management carried out to ensure that high quality vegetated shingle and bare shingle are retained over an area much as at present.

Natural succession and grassland

The small areas of grassland may also be vulnerable to natural succession in the very long term (i.e. gradual build up of organic soil and eventual colonisation by shrubs and trees). A simple fixed-point photographic monitoring programme would be a simple way to keep a watch on this.

However, natural succession in these areas is probably extremely slow due to the periodic inundation by the saline water of the lagoon and trampling by picnickers and dog walkers (e.g. of the Thrift grassland).

Natural infilling of the lagoon

Lagoons are by their nature not static systems, either physically or biologically and they are by nature ephemeral habitats, which develop and disappear within centuries. They are created by natural processes associated with natural changes in estuaries and along coasts and their longevity depends on the influence of natural factors. Natural infilling occurs for several reasons:

(a) Build up of organic matter (resulting from the decomposition of plants and animals in the lagoon) and settlement of silt brought in with seawater and (b) deposition of gravel and beach material during storms, (a) is not usually considered to have a very significant impact, due to the efficient recycling of nutrients within lagoon ecosystems. However, (b) may be significant at least along the seaward embankment where overtopping by storms results in the dumping of beach shingle inside the basin.

At Widewater because there is no information on the substrate (except for surface sediments), it is not possible to determine to what extent the lagoon is being naturally in filled with shingle. As 'outlined above, shingle appears to have built up at least for 1.38 metres at one point on the lagoon’s southern edge, but whether or not this has occurred over the whole site is unknown.

If shingle has built up along the bed of the lagoon, this will mean that the amount of water in the lagoon will have become less over time (although levels O.D. may have remained the same). If there has been a significant build up of shingle over the last 50 years on the lagoon bed/ then one option for improving the quality of water in the lagoon may be to dredge the bed in order to attain the bed level typical to some date in the past (c.1900?). Artificial deepening of the lagoon may also be necessary to reduce the distance between its bed and sea level (and therefore increase the amount of water in it).

Destruction of the beach barrier by storm

Breaching of the seaward barrier may also lose lagoons. In fact the Widewater has been threatened as recently as 1989-90 when there was a dramatic and unprecedented loss of beach material from the foreshore and a threatened breach of the seaward barrier.

Man-induced trends and other external factors

Man-induced trends are many. However, as with natural factors, the precise effects of these are not known.

Pollution

The lagoon has suffered from moderate pollution as indicated by heavy metal levels in the sediment and water. Bio available levels are not considered particularly significant at the present time.

Coastal defence work

It is possible that coastal defence work may have affected the rate of percolation through the shingle bank, and hence reduced the source of replenishment of seawater to the lagoon. This is difficult to ascertain due to the lack of data on levels O.D. within the lagoon and their relation to mean low water at sea level.

The post-war work on the sea defence, which included dumping of refuse and other materials, has quite possibly reduced the permeability of the seaward shingle bank, but there are no data to support this assumption.

Also, the gradual heightening of the sea defences may have reduced the number of overtopping incidents, and the primary source for colonisation and recolonisation of aquatic invertebrates. This problem has been identified as a general one for lagoons in Britain (Bames 1991). Bames considers that storm surges are probably the major means of dispersal for characteristic lagoonal species and that post-1953 coastal defence work may have rendered most populations of lagoon species relict by cutting off the supply of (re)colonists.

Island construction

The construction of the bird island in the eastern part of the lagoon is thought to have destroyed an inlet where the sea percolated into the lagoon (this may have been a crack in the underlying clay), thus reducing the seawater input and output.

Urban development and land drainage

The immediate surrounds of the lagoon have changed little since the houses were first built on the northern edge of the lagoon in the 1920s. Additional houses were constructed on the eastern bank several years ago but are unlikely to have had much of an impact on the lagoon.

The recent surface drainage scheme undertaken on the Hasler Estate north of the Brighton Road is unlikely to have affected the Widewater.

Causeway construction

The integrity of the site has been damaged by the construction of two causeways across the site.

The western causeway has effectively isolated a western arm of the lagoon, thus making it more vulnerable to environmental stress and reducing the possibility of recolonisation by lagoonal animals (although there is apparently a small culvert through it this is insufficient to maintain water levels).

3.2.4.5: Past management for nature conservation

Widewater residents have, from time to time, lobbied the authorities for action over the Widewater, mostly in relation to clearing rubbish from it or for action to reduce the smell and summer algal blooms. In 1982 a Conservation Policy for the Widewater (Adur District Council 1982) was produced. This proposed a community project for the Widewater for the purposes of enhancing it for the public benefit. Projects carried out were removal of litter and creation of island(s) for wildfowl.

3.2.4.6: Present Legal Status of the Site

(i) Local Nature Reserve

(ii) West Sussex (County Council) Site of Nature Conservation Importance

3.2.4.7: Biodiversity Action Plans Obligations

The present approach to the conservation of wildlife and habitats in the UK has been developed following the Earth Summit in Rio in 1992. The UK Action Plan was produced in 1994 and, at a more local level, a Sussex Biodiversity Act Plan (BAP) was published in 1998. Through partnerships it is intended that the Action Plan will focus resources to conserve and enhance biodiversity. Priorities and targets will be identified for a range of habitats and species: it is important that the review of the Management Plan is a vehicle through which Pagham Harbour can play its part in the delivery of the BAP. Sussex has produced it own Local Biodiversity Action Plan. A Local Biodiversity Action Plan works on the basis of partnership to identify local priorities and to determine the contribution they can make to the delivery of the national Species and Habitat Action Plan targets.

Habitat Action Plan (HAP) - The Sussex Biodiversity Partnership has published HAPs for the majority of principal habitats in Sussex: the priority is to concentrate on those under most pressure, some of which are represented at Widewater. The HAP's that have been published that directly affect the management objectives of Widewater are those for Saline Lagoons and Coastal Vegetative Shingle, these plans can be accessed at http://www.ukbap.org.uk/

3.2.4.8: The Site in a Wider Perspective and Implications for Management

The site is one of the few remaining areas of semi natural habitat along this section of coastline is extremely important for the wildlife that uses it, also it is a part of a series of small similar patches of land which have not been developed in the area and provides an important link in the chain for many species which move up and down the coast. It is also an important area for the local community to use. With its relatively isolated nature, as it is surround by a variety of domestic properties which have huge implications to any management that is carried, particular in relation to coastal defence strategies and flooding issues. Also with a large population close to the Reserve, there is a great deal of public pressure to manage it in a certain way to benefit them and not necessarily the best for the conservation aspects.

3.3: Current Public Use

3.3.1: Public interest/relationship with local communities

The site is situated in the urban environment and therefore attracts a wide range of interest from the public in general. The majority of the visitors use it as a recreational resource for walking dogs, having a stroll and using the car parking facilities for water sports out on the sea. A small number of the visitors come to appreciate the nature value of the site in particular birdwatchers. The high number of visitors to the site increases the disturbance factor, which will acutely affect bird species such as breeding ringed plover. Another potential problem is the nutrification of the vegetation adjacent to the Lagoon through dog fowling.

The site is closely located to a large number of residential properties, which presents a number of potential issues.

A survey in 1992-93 showed that the majority of people questioned wished Widewater to be kept as a 'natural resource'. However, there were a significant number of people who wished to see the area developed as a recreational facility. Of the latter, two thirds were in the age group 12-30 and most of these came from Lancing. A smaller number indicated they would like to see the area developed for both recreation and nature conservation.

Another study on the recreational potential of the Widewater was carried out in 1993 (Should Widewater Lagoon be further developed for recreation? (Emma Freeman, 1990). This concluded that the lagoon was biologically unsuitable for development, and that Widewater should not be further developed for recreation.

3.3.2: Tourism and current recreational use

Current facilities

These are: two large car parks which cover over 2 acres of land, and which do not appear to be full on many days of the year. There are Public conveniences with for the disabled or parent/baby facilities. There is a refreshment kiosk between the two car parks and three interpretative signs mounted on stone plinths at the kiosk, the entrance point to the Main Causeway and adjacent to the 'footpath which goes across the western causeway.

Access considerations

The site is well served by public footpaths (see Map 3) and permissive rights of way. At present there is unrestricted access to the lagoon itself from any point along the south bank and car parks. A public footpath that used to go along the north bank (through gardens of Brighton Road properties) was closed in 1993.

3.3.3: Current interpretation provision

The site has a wooden routed signs at all entrances, stating the boundaries of the reserve. The education booth has information on the salinities. Lancing Parish Council has a sign relating to the car parks and please do not pick the wild flowers.

In 2009 a series of more detailed interpretation boards were put up along the cycleway.

3.3.4: Current educational use

There is an education booth sited at the Western end of the Lagoon by the car park entrances. Currently volunteers man it during the summer months. There is a display of up to date photos of flora and fauna for people to see when the booth is shut.

The site is rarely used by schools but is visited by Brighton University for field trips.

3.3.5: Current research use and facilities

The lagoon has been the subject of a number of studies. A full bibliography is given in Section 2.5 Particular mention should be made of the long term monitoring and other ecological research, which has been undertaken by Southampton University's Department of Oceanography. This research has focused on the ecology of the lagoon and has contributed much useful information, which as helped to reach an understanding of coastal lagoons in general.

Widewater is also the focus of a hydrology project being undertaken by Bristol University, titled 'Geochemistry of the freshwater/seawater mixing zone in sands, gravels and weathered chalk at Lancing, Sussex'. This has involved the construction of a borehole in the south shore (east of Main Causeway) and sampling cores from the chalk to look at the characteristics of and movement of interstitial water.

3.4: Landscape

A large extent of the South coast between Brighton and Bognor Regis has been urbanised with very few undeveloped areas remaining. The Lagoon lies at the eastern extent of this development and provides a small but significant impact on the local landscape. It provides one of the few remaining large extent of standing open water along this section of the coastline and acts as a buffer zone from the sea for local housing. It is also connected to the Adur Estuary via the shingle beach, which runs almost the entire section of coast acting as a natural sea defence (although regular work is carried out to maintain it). This complex of habitats creates a desirable break in the ribbon development that has progressed along the coast. Behind this, much of the coastal plain has been affected by agriculture, leaving the lagoon and the estuary as one of the few remaining areas of semi natural habitat along this stretch of coastline from Worthing to Shoreham.

3.5: Bibliography

Note: This listing does not claim to be comprehensive and does not include references to some of the unpublished student theses, which have been written on the Widewater, and for which no information was available during the preparation of this management plan.

References specific to Widewater and its locality

Adams, H.C. 1891. History of the Shorehams. A.F. Tower.

Adur District Council. 1982 & 1984. A conservation policy for the

Widewater. Adur District Council. 1985. Adur District Local Plan.

Booth Museum of Natural History. Sussex plant atlas. Brighton

Borough Council.

Booth Museum of Natural History. Sussex plant atlas: Supplement.

Brighton Borough Council.

Brace et.al. (1998) Sustainable Management of the Widewater Lagoon.

MEng dissertation, University of Surrey

Everett S (1993) Widewater Lagoon Management Plan

Green, B. 1877. New Shoreham. Sussex Arch. Coll, 27: 98.

Hancock Ward, K.M. 1983. A survey of the benthic macrofauna of

Widewater Lagoon, Sussex. MSc Thesis submitted to the

Department of Oceanography, University of Southampton.

Irving P. A. (1997) WWF-UK Survey of Widewater Lagoon, Lancing,

West Sussex

Ivell, R. 1979. The biology and ecology of a brackish lagoon bivalve

Cerastoderma glaucum in an English lagoon, the Widewater,

Sussex. J. of Molluscan Studies, 45: 383-400.

Joyce, C. 2005. Biotic variation in coastal water bodies in Sussex,

England: Implications for saline lagoons. Estuarine, Coastal and

Shelf Science 65 (2005) 633-644

Joyce, C. Various surveys (not Published) 2001 - 2005

Katsanos A. (1998) Feasibility Study on the Restoration and

Maintenance of Widewater Lagoon, West Sussex. B.Eng

dissertation. University of Surrey

Kerridge, R.G.P. 1979. A history of Lancing. Phillimore.

McDonagh, L. and Sheader, M. 1991. Deterioration in the biota of

Widewater Lagoon, West Sussex and colonisation of newly

created lagoons at Normandy Farm, Lymington, Hampshire. BSc

Thesis submitted to the Department of Oceanography, University

of Southampton.

Management Plan Review 2000 - 2005 Dolphin Ecological Surveys

Manuel, R.L. 1975. A new sea anemone from a brackish lagoon in

Sussex, Edwardsia ivelli sp. nov. Journal of Natural History, 9:

705-711.

Minutes of the Widewater Local Nature Reserve Management Liaison

Group, 18/6/98, 17/11/98 and 27/4/99

Schleifer, P. 1988. A study of the changes of the ecology of Widewater

Lagoon, Sussex. BSc Thesis submitted to the Department of

Biology, University of Southampton.

Sheader, M. & Sheader, A. 1990. A survey of Widewater saline lagoon

to determine the current status of the site, with special reference

to Ivell's sea anemone Edwardsia ivelli. Preliminary Report to the

N.C.C. Department of Oceanography, University of Southampton.

Sheader, M., Sheader A. &: Hawkins/ L.E. 1993. Widewater Lagoon

Survey on 29 July, 1993, to provide current information on which

to base a management strategy.

Smith, D. 1992. The birds of the Widewater/ Lancing. Shoreham

District Ornithological Society.

Southampton University. 1993. Widewater Lagoon - nutrient and

heavy metal concentrations. Department of Oceanography,

University of Southampton.

Various biological records from J. Knight, B & G Bishop and SDOS

Ward, K.M.H. 1983. A survey of the benthic macrofauna of Widewater

Lagoon, Sussex. MSc Dissertation/ University of Southampton.

Water Level Monitoring Data May 1995 to February 2000 from FOWL, L

Howard

Watkins D. (1997) Characteristics of Physio-chemical Water

Parameters and Circulation Patterns in the Widewater Lagoon,

West Sussex BSc dissertation. University of Surrey

West Sussex County Council. 1991. A nature conservation strategy for

West Sussex.

West Sussex County Council. 1992. Towards a coastal strategy for

West Sussex.

Other general references (e.g. re nature conservation and saline lagoons)

Adur District Local Plan April 1996

Anon (1 W) Biodiversity: The UK Action Plan. DoE

Bamber, R.N., Batten, S.D./ Sheader M. & Bridgwater, N.D. 1992. On

the ecology of brackish water lagoons in Great Britain. Aquatic

Conservation, 2: 65-94.

Bames, R.S.K. 1974. Estuarine biology. Studies in biology no. 49.

Edward Arnold.

Bames, R.S.K. 1980. Coastal lagoons: the natural habitat of a

neglected habitat. Cambridge University Press, Cambridge.

Bamew, R.S.K. 1989. The coastal lagoons of Britain: An overview and

conservation appraisal. Biological Conservation, 49: 295-313.

Bames, R.S.K. 1991. European estuaries and lagoons: a personal

overview of problems and possibilities for conservation and

management. Aquatic Conservation, 1: 79-88.

Boyden, C.R. & Russell, P.J.C. 1972. The distribution and habitat range

of the brackish water cockle Cerastoderma glaucum in the British

Isles. J. Animal. Ecol., 41: 719-734.

Boyden, C.R. 1971. A comparative study of the reproductive cycles of

the cockles’ C. edule and C. glacum. Mar. Biol. Ass. UK., 51: 605-

22.

Brook, V. 1979. Habitat selection of two congeneric bivalves C. edule

and C. glaucum in sympatrix and allopatrix populations. J. Mar.

Biol. Ass. UK., 54:149-56.

Buchanan, J.B. 1971. Measurement of the physical and chemical

environment. Chap 3: Methods for the study of the marine

benthos. Ed./ Holme, N.A. & Mclntyre/ A.D. Blackwell Scientific

Publications/ Oxford.

Colombo, G. 1977. Lagoons; The coastline. Ed., Bames, R.S.K. pp 63-

81. Wiley, London & New York.

Cromwell, J.E. 1971. Barrier coast distribution: a worldwide survey.

Abstr. vol. 2nd nat. coast. shallow water res. conf. p 50.

Curson J. (2000) Draft Saline Lagoon Habitat Action Plan, EN

Emery, K.0.1969. A coastal pond studied by oceanographic methods.

Elsevier, New York.

EN (1997) Folkestone to Selsey Bill Natural Area Profile

Gray, J.S. 1981. The ecology of marine sediments: an introduction to

the structure & function of benthic communities. Cambridge

University Press, Cambridge.

Joint Nature Conservation Committee. 1993. Coastal vegetated shingle

structures of Great Britain.

Joint Nature Conservation Committee. 1991. British Red Data Books:

3. Invertebrates other than insects.

Joint Nature Conservation Committee. 1989. Guidelines for selection of

biological SSSIs.

Kingston, P. 1974. Studies on the reproductive strategies of C. edule

and C. glaucum. Mar. Biol., 28: 719-734.

Lloyd, M. & Ghelardi, R.J. 1964. A table for calculating the equitability

component of species diversity. /. Anim. Ecol., 33: 217-225.

MacArthur, R.H. & Wilson, E.O. 1967. The Theory of island

biogeography. Princeton University Press.

Manuel, R.L. 1981. British anthozoa. Synopses of the British fauna:

New Series; no. 13. Academic Press.

Margalef, D.R. 1958. Temporal succession 6' spatial heterogenity in

phytoplankton. Perceptive in marine biology; Ed., Buzzati-Traverso

A.A. University California Press, Berkeley.

Mee, L.D. 1978. Coastal lagoons. Chemical oceanography, 2nd Edition,

vol 7: pp 441-90. London Academic Press.

Pye, K. & French, P.W. 1992. Targets for coastal habitat recreation.

Report for Natural England. Cambridge Environmental Research

Consultants Ltd.

Nature Conservancy Council. 1989. Guidelines for selection of

biological SSSIs.

Nature Conservancy Council. 1988. Site management plans for nature

conservation: a working guide. Peterborough.

Nossier, M.A. 1980. Multiple approaches to the taxonomic status of C.

edule and C. glaucum. PhD Thesis, Southampton University.

Sanders, H.L. 1968. Marine benthic diversity: a comparative study.

Amer. Nat. 102: 243-282.

Sheader, M. & Sheader, A.L. 1985. Survey of brackish coastal lagoons,

Sussex to Dorset. N.C.C. Field Report No. HF 3/11/37.

Sheader, M. & Sheader, A.L. 1989. The coastal lakes and ponds of

England and Wales: an overview. A report submitted to the

N.C.C.

Sheader, M. & Sheader, A.L. New records for lagoonal species in

Britain. Department of Oceanography, University of Southampton.

Smith, B.P. & Laffoley, D. 1992. A directory of saline lagoons and

lagoon like habitats in England. Natural England, Peterborough.

Sorenson. 1948. Ecological methods. Ed., Southwood, T.R.E. 1978.

Chapman & Hall, 2nd edition. Venice System. 1959. Final

resolution of the symposium on the classification of brackish

waters. Archo. oceanog. limnol., 11: 243-245.

UK Biodiversity Group (1999) Tranche 2 Action Plans, volume V -

maritime species and habitats. EN

Warwick, R.M. 1986. A new method for detecting pollution effects on

marine macrobenthic communities. Mar. Biol. 92:557-562.

Warwick, R.M., Pearson, T.H. & Ruswahyuni. 1987. Detection of

pollution effects on marine macrobenthos: further evaluation of the

abundance/biomass method. Mar. F:ol., 95: 193-200.

4: Nature Conservation Features of Interest

4.1: Identification and confirmation of conservation features

4.1.1: List of recognised conservation feature

Feature 1 The Saline Lagoon with special reference to Lagoon Specialists (Compartment 1)

Saline lagoons represent a very rare habitat both in the UK and in Europe. They are identified as a 'priority natural habitat type' in the European Habitats Directive.

Feature 2 The Vegetated shingle with special reference to shingle specialists (Sub-compartment 2.2)

Vegetated shingle is a rare habitat in the UK. That represented at Widewater Lagoon falls into the NVC (National Vegetation Classification) category SDIa Crambe maritima /Glaucium flavurn shingle community (unstable shingle), typical sub-community of Rumex crispus - Glaucium flavurn with a very narrow strandline community of SD3 Atriplex hastata/Beta vulgaris ssp. maritime.

Feature 3 Other Terrestrial Habitats (Sub-compartments 2.1, 2.3 and 2.4)

The other habitats represented on the site are not individually important but, together with the vegetated shingle and open water of the lagoon; providing a good mosaic of coastal habitat.

Feature 4 Regionally Important Bird Interest with particular reference to Ringed Plover

The lagoon is a well watch site and provides some limited opportunities as a stop over for various migrant waders. The main ornithological interest is the small but regionally important breeding population of ringed plover.

Feature 5 Recreation, education/research and amenity (All Site)

The site is situated close to the large populations of Worthing and Shoreham and provides an important resource to the local community for both formal and informal recreation/education.

Feature 6 Administration of the Area

5: Obligations

5.1: Identification/confirmation of Obligations

5.1.1: Strategy Obligations

County Structure Plan

Areas of importance for nature conservation Policy C3 - Only in compelling circumstances will development (or changes of use or management), be permitted where it would be harmful to Sites of Special Scientific Interest, Ramsar sites. Special Protection Area; or to other sites and areas identified as being of nature conservation or geological importance, including significant wildlife corridors. Need for development essential for agriculture or forestry or to take advantage of a valuable opportunity to meet demand for the extraction of minerals or the deposit of waste may exceptionally be regarded as compelling. Applications will be subject to the most rigorous examination because of the possible impact of such development on sites of nature conservation or geological importance.

Conservation of landscape and wildlife habitats

Policy C14 the planning authorities will seek to protect, conserve and enhance the quality and distinctive character of the landscape in different parts of the county and to protect wildlife habitats and species. Particular attention will be paid to AONBs and their settings, SSSIs, Ramsar sites. Special Protection Areas and other sites of nature conservation and geological importance, and sites in which the Planning Authorities themselves have an interest. Practical measures to be taken will include seeking the retention, management and conservation of wetlands and other habitat types rare in the county and of significant wildlife corridors, creating, conserving, managing and improving wildlife habitats, including local nature reserves.

Local Plan (Adur District Local Plan Consultation Draft 1985)

Note: bracketed texts are not policies.

Countryside Policy Cty 8 The local planning authority will seek to secure the protection and conservation of areas of ecological interest in the countryside.

Policy Cty 9 The local planning authority will encourage, where appropriate, schemes or projects designed to conserve or improve landscape and which encourages nature conservation.

Recreation and tourism Policy Rec 1 Land subject to this policy shall continue to be used only for public open space during the local plan period and shall not be used for any other purpose (includes 'Lancing Green, Beach and Widewater').

Policy Rec 11 The local planning authority will seek to ensure the continued maintenance and improvement of the public beaches and associated facilities in its ownership (Lancing Beach, the adjacent Beach Green, Beach Lawn and public car park which are the responsibility of Lancing Parish Council). That Council has recently improved the area and further measure to improve the environment and facilities will be encouraged.

Policy Rec 12 The local planning authority will encourage measures to improve facilities for the public at Lancing Beach, the associated Beach Green and Beach Lawn public open space.

Nature conservation

The Widewater constitutes the remains of a former watercourse, which has been almost completely obliterated because of changes in the coastline, and the course of the River Adur. The District Council has already implemented a conservation project, which is contributing towards its restoration to a natural state. Its continued existence and maintenance needs to be ensured.

Policy Env 14 The local planning authority will seek to retain the Widewater area, shown subject to this policy on the proposals maps, in its natural state and will resist any development likely to be harmful to its ecology.

A nature conservation strategy for West Sussex

This document (West Sussex County Council 1991) sets out policies for protecting and managing important nature conservation sites, for maintaining information about nature conservation and to promote public enjoyment and awareness over nature conservation. The policies give particular priority to protecting and enhancing 'Sites of Nature Conservation Importance (SNCIs) which have been identified by the County Council. These are 'sites identified on account of the special interest of their flora and/or fauna (i.e. sites with very considerable wildlife value). A panel of professional ecologists from West Sussex County Council, Natural England and the Sussex Wildlife Trust selects SNCIs. Widewater Lagoon is an SNCI. In 1997 the site was designated a Local Nature Reserve

5.1.2: Legal obligations of the Occupier's Liability Act

As occupiers of the land. Lancing Parish Council has liability for the safety of all visitors to the land, whether they are there by right, by permission, or by trespass. The Council is also responsible for any hazard to visitors from structures, but not for natural hazards.

5.1.3: Constraints of tenure

Lancing Parish Council does not own the eastern corner of the Widewater.

5.1.4: Flood defence designation

The area extending from the sea to the Brighton Road comes under the jurisdiction of the Environment Agency, in its capacity as the authority responsible for flood defences here. The sea wall is a primary sea defence and the north bank is a secondary sea defence. Any work carried out within the area must therefore be subject to the agreement of the Environment Agency.

5.1.5: Managerial constraints

There are no members of staff who have sole responsibility for management of the Widewater. This situation needs to be remedied. There needs to be a point of contact between the local residents and a representative of the parish council, and a member of staff or contractor who has responsibility for litter collection, weed cutting, and other manual tasks which may be necessary at the site. Furthermore, a qualified ecologist must oversee conservation management at Widewater. Substantial operations (e.g. culvert construction, artificial replenishment) must be properly supervised 'on the ground' and will require a high input of professional skills (ecologist, hydrologist, engineer).

Appendix 1: Site Boundaries and Tenure

Appendix 2: Location of Salinity and Height Readings

Appendix 3: Location of Compartments

Appendix 4:VegetationMap

Western Section

Eastern Section

Appendix 5: Species List for Lagoon Invertebrates

Common Name	Date
Abra tenuis	24/08/2005
Arenicola marina	24/08/2005
Bowerbankia gracilis	24/08/2005
Cerastoderma glaucum	24/08/2005
Chaetomorpha mediterranea	24/08/2005
Chironomidae	24/08/2005
Cladophora laetevirens	24/08/2005
Cumacea	24/08/2005
Enteromorpha flexuosa subsp. pilifera	24/08/2005
Gammarus	24/08/2005
Hydrobia ventrosa agg.	24/08/2005
Isaeidae	24/08/2005
Maera grossimana	24/08/2005
Microdeutopus gryllotalpa	24/08/2005
Palaemonetes varians	24/08/2005
Ruppia maritima	24/08/2005
Ulva lactuca	24/08/2005
Abra tenuis	31/08/2004
Arenicola marina	31/08/2004
Bacillariophyceae	31/08/2004
Cerastoderma glaucum	31/08/2004
Chaetomorpha mediterranea	31/08/2004
Chironomidae	31/08/2004
Cyanophyta	31/08/2004
Whiteworm	31/08/2004
Gammarus	31/08/2004
Hediste diversicolor	31/08/2004
Hydrobia ventrosa agg.	31/08/2004
Littorina saxatilis subsp. rudis	31/08/2004
Maera grossimana	31/08/2004
Melinna palmata	31/08/2004
Palaemonetes varians	31/08/2004
Ruppia maritima	31/08/2004
Ulva lactuca	31/08/2004
Abra tenuis	22/07/2003
Arenicola marina	22/07/2003
Bowerbankia	22/07/2003
Bryozoans	22/07/2003
Cerastoderma glaucum	22/07/2003
Chaetomorpha mediterranea	22/07/2003
Chironomidae	22/07/2003
Whiteworm	22/07/2003
Gammarus duebeni	22/07/2003
Hediste diversicolor	22/07/2003
Hydrobia ventrosa agg.	22/07/2003
Littorina saxatilis subsp. rudis	22/07/2003
Lysianassidae	22/07/2003
Maera grossimana	22/07/2003
Melinna palmata	22/07/2003
Palaemonetes varians	22/07/2003
Perinereis cultrifera	22/07/2003
Ruppia maritima	22/07/2003
Tubificoides benedii	22/07/2003
Ulva lactuca	22/07/2003
Abra tenuis	21/08/2002
Arenicola marina	21/08/2002
Berosus	21/08/2002
Cerastoderma glaucum	21/08/2002
Chaetomorpha mediterranea	21/08/2002
Chironomidae	21/08/2002
Cyanophyta	21/08/2002
Gammarus duebeni	21/08/2002
Hediste diversicolor	21/08/2002
Hydrobia ulvae	21/08/2002
Ventrosia ventrosa	21/08/2002
Hydrobia ventrosa agg.	21/08/2002
Hydrobius	21/08/2002
Maera grossimana	21/08/2002
Melinna palmata	21/08/2002
Nemertea	21/08/2002
Palaemonetes varians	21/08/2002
Perinereis cultrifera	21/08/2002
Ruppia maritima	21/08/2002
Schistomysis	21/08/2002
Ulva lactuca	21/08/2002
Abra tenuis	22/06/2001
Actinauge	22/06/2001
Arenicola marina	22/06/2001
Bacillariophyceae	20/08/2001
Berosus spinosus	22/06/2001
Cerastoderma glaucum	22/06/2001
Chaetomorpha mediterranea	22/06/2001
Chironomidae	22/06/2001
Cladophora laetevirens	22/06/2001
Conopeum seurati	22/06/2001
Corixa	07/07/2001
Cryptosula pallasiana	23/07/2001
Derbesia marina	22/06/2001
Electra	20/08/2001
Whiteworm	22/06/2001
Enochrus melanocephalus	22/06/2001
Enteromorpha flexuosa subsp. pilifera	22/06/2001
Gammarus duebeni	07/07/2001
Golfingiidae	20/08/2001
Halecium	20/08/2001
Hediste diversicolor	07/07/2001
Helochares lividus	20/08/2001
Helochares punctatus	22/06/2001
Hydrobia neglecta	22/06/2001
Hydrobia ventrosa agg.	22/06/2001
Lekanesphaera	22/06/2001
Littorina saxatilis subsp. rudis	20/08/2001
Littorina saxatilis subsp. tenebrosa	20/08/2001
Lumbricidae	22/06/2001
Membranipora membranacea	23/07/2001
Palaemonetes varians	07/07/2001
Perinereis cultrifera	07/07/2001
Rhizoclonium tortuosum	22/06/2001
Rissoacea	20/08/2001
Ruppia maritima	22/06/2001
Tubificid Worm Sp.	20/08/2001
Ulva lactuca	20/08/2001
Beadlet anemone	1931
Bougainvillia muscoides	1931
Bryozoans	1931
Cockle	1931
Brackish hydroid	01/09/1990
Brackish hydroid	1993
Corophium volutator	1931
Cyprideis torosa	1993
Ivels sea anemone	1983
Lagoon Sand Shrimp	1982
Gonothyraea loveni	1931
Idotea chelipes	01/09/1990
Sea Slater	01/09/1990
Littorina saxatilis	1982
Common mussel	1931
Polydora ciliata	1985

Appendix 6: Work Programme

Maintain Lagoon in favourable condition by: -

Impact of wildfowl

§ Monitor species/numbers

§ Monitor Ring Plover

Impact of Recreational Activities

§ Collect data on visitor numbers

§ Monitor Dog disturbance

§ Removal of litter

Water Quality

§ Water levels -(height in metres)

§ Salinity levels (ppt)

§ Lagoon species, Biodiversity Action plan (BAP), Habitat Action Plan (HAP)

Vegetated Shingle

§ Maintain vegetated shingle by removing alien species

§ Collect data of vegetated shingle communities, plant surveys.

§ Collect data of invertebrates

Grasslands

§ Invertebrate survey, (grasshoppers, beetles etc)

§ Plant surveys

§ Small mammal survey

§ Remove alien species, i.e. Japanese Knotweed, Ragwort.

Car Parks

§ Repair/improve car parks

Interpretation

§ Review and rationalise as necessary

§ Information booth to be maintained by local group

Feature 1 - The Saline Lagoon with special reference to Lagoon Specialists

Description

The primary importance of the Widewater was for its lagoonal invertebrate species, which are characteristic of saline lagoons and very sheltered estuaries. The Widewater was also renowned for its rarities, including Ivell's Sea Anemone Edwardsia Ivelli (for which it was the only known site in the world) and the hydroid Clavopsella navis, which is still present (now currently known from one other site in the world).

Since 1931 the aquatic flora and fauna has changed, but it is possible that the sampling carried out between 1978 (point sampling) and 1993 will not have detected very low numbers of some species which may have declined due to the poor conditions of the lagoon (particularly during the recent drought). Assessment of fauna abundances show how great the changes have been, with the number of species per core falling from 744 in 1987 to a low of 31 in 1990. An increase to 80 in July 1993 indicates some recovery. The table below shows that a substantial invertebrate interest still remains, and if a new seawater inlet is constructed and rainfall returns to normal over the next few years, there is every hope for a significant recovery of the lagoon in terms of its water quality and invertebrate fauna. Sheader considers that Edwardsia and Clavopsella were probably misidentified in 1931. Gammarus insensibilis did not 'exist' as a separate species in 1931 but was originally split off in the 1970s from G. locusta, which was recorded in 1931.

Clavopsella navis This is a hydroid which attaches itself to Chaetomorpha and Enteromorpha and has been recorded from only three sites around the world, all of which were, or are, harbours: the Kiel Canal (current status unknown), Cape town (South Africa) and Widewater. The dock at Cape Town where it was recorded has since been in filled.

Cerastodenna glaucum Lagoon Cockle This declined markedly in numbers following the 1989/90 drought and accounted for the large reduction in biomass recorded in 1990, when its distribution was restricted to sheltered areas where they remained permanently submerged. The cockle may also have declined in the remaining water due to the increased salinity in 1990 - its normal tolerance range is 23-35. This is another species typical of lagoons and very sheltered estuaries. In the UK it is distributed mainly along the South and East Anglia coastline. It is dependent on a habitat, which is scarce. It is common in the Baltic and in the Mediterranean.

Littorina saxatalis tenebrosa This is a subspecies of L. saxatalis, a species of periwinkle. It has not been recorded from the Widewater since the period 1978-82 and may be now be extinct.

Other species of interest:

Eurytemora americana (A copepod recorded from brackish pools. By 1874 it was known in Britain only from Sussex and the Isle of Wight. Elsewhere it has been recorded from Nova Scotia and the Sea of Okhotsk, Russia. (Invertebrate Site Register for Widewater Lagoon, English Nature 1993)

Objective 1

Maintain Saline Lagoon In Favourable Condition

Factor List

1 - The impact of visiting Wildfowl

Collect data, birds, monitor - Monitor the number wildfowl on site

Shoreham and District Ornithological Society Carry out regular recording of the waterfowl on site.

Collect data, birds, research project - To establish the wildfowl carrying capacity of the lagoon

Research Project for Student

2 - The impact of recreational Use

Collect data, public use, recreation - Collect Data on the recreational use of the site

Attribute List

1 - The Water Quality

Collect data, hydrological, monitor - Monitor the salinity levels of the lagoon - east

Collect data, hydrological, monitor - Monitor the salinity levels of the lagoon - Bridge

Collect data, hydrological, monitor - Monitor the salinity levels of the lagoon - Pipe

Collect data, hydrological, monitor - Monitor the salinity levels of the lagoon - west

2 - Water Levels

Collect data, hydrological, monitor - Monitor the water levels of the Lagoon

3 - The community of saline invertebrates

Collect data, other invertebrates, monitor - monitoring of the specialist saline invertebrates

4 - The floral communities of the Lagoon

Collect data, vegetation, monitor - Monitor the floral communities of the lagoon

5 - The Terrestrial Fauna

Collect data, mammals, survey - Carry out small Mammal Trapping

Collect data, birds, general - Maintain Current Records

Collect data, Orthoptera, survey - Carry out a baseline survey

6 - The Terrestrial Flora

Collect data, vegetation, survey - Repeat 1994 survey

Management Rationale

Lagoons are water bodies with a salt content ranging from about 8 ⁰/₀₀, which is hyposaline to 40⁰/₀₀, which is hypersaline. (Where the salinity of seawater is 35⁰/₀₀). The salinity level is control by various physical conditions such as rainfall, freshwater and seawater inflows. The salinity will also vary throughout the year making these habitat extreme and only very specialised flora and fauna can thrive in these conditions. There are five different types of lagoon

Saline inlets- where there is a connection to the sea.

Isolated lagoons- almost separated from the sea with input of saltwater though a ground source or storms

Percolation Pools- seawater percolates through a shingle or permeable barrier

Sluiced Ponds- artificially controlled lagoons

Silled Lagoons- where a sill obstructs the movement of seawater

These extreme environments not only do they have this range of varying saline’s many of them are constantly being formed and eroded making them unstable systems. They are also in areas that are influenced by mans activities, making them a threaten habitat with only 177 recognised in England, 13 in Wales and 139 in Scotland.

The lagoon support a very specialised wildlife associated with it, species such as Lagoon Cockle, Ivell’s Sea anemone, the Hydroid Clavopsella navis and various marine worms. Also the flora is special with the nationally rare Beaked Tasselweed thrive in this environment.

Like many of their freshwater equivalents this system is under the influence of successional forces driving it to dry out and become a terrestrial habitat. Also the geomorphic forces that are constantly present shape the lagoons and provided the unique conditions that these specialist organisms require. These habitats are very vulnerable to a variety of factors including drought, pollution, nutrification and siltation from run off. Management for the lagoon is require in order to maintain the required conditions and to counter the factors that will adversely affect these Lagoons.

Management List

1 - Control of Water and Salinity Levels

Manage habitat, open water / rivers, by water level control - Manage the Water Levels

The water level is control by a pipe which runs through the shingle beach to the sea, which was, install in 2002/03 . The pipe was fitted with a series of valves and weirboards. the operation of the pipe is carried out by WSCC, but ownership remains with the Environment Agency. The pipe operates using the height of the tide, a series of weirboards and key operated drop sluice.

Settings

1. Fully open and no weirboards -- will allow water in on a 5.2m tide or above

2. Fully open with max of 10 weirboards -- will allow water on 6.2m tide or above

3. Fully open with weirboards 1 - 9 -- will allow water in on a variety of tides heights depending on the number of weirboards

4. fully closed -- no water in from sea through pipe

5. Partially open has been attempted but has little effect (similar to fully open position) therefore sluice is either open or closed there can be an effect on the volume entering on the high tide by the wind direction

The water level is monitored monthly and with the use of the information gathered from the height boards the setting of the pipe can be establish. the aim is to manage the Lagoon in order not compromise any of the identified features but maintain an adequate muddy margin to allow passage and resident bird population feeding areas. the local human residents are informed when alterations to the pipes settings are made.

Also monitored monthly is the salinity of the lagoon and in low water flow (drought) conditions this will raise. These hyper-saline conditions are detrimental to the Lagoon Specialists (preferences being of a salinity between 15 and 40 ppt) and usually indicate low water levels as well. Under such conditions water is allow in from the sea to raise water levels as well as to dilute the water present in the Lagoon

Feature 2 - The Vegetated shingle with special reference to shingle specialists

Description

Vegetative Shingle is a complex and very unstable environment creating a series of specialist niches which can only be inhabited by the most stress tolerance plants and invertebrates. The nature of shingles communities being at the early stages of succession and extreme mobile means that the communities and species associated with them are also very vulnerable to change. Many of the plant species are considered rare or scarce. of particular important are;

The vascular plant Crambe maritima Sea Kale is Nationally scarce. Found in 88 10 km squares in the British Isles (Nature Conservancy Council 1989). Usually found on coastal shingle but absent from many areas. Its distribution in south England: This species core distribution in Great Britain is sandy and singly shores and cliffs in south-east England, where it is locally frequent along the coast in south Hampshire, Sussex and Kent.

Franconia leaves Sea Heath is nationally scarce. Found in 25 10 km squares in the British Isles (Nature Conservancy Council 1989). Considered native on sandy or salty bearish ground on drier parts of salt marshes along coasts of the Channel Isles and South East Britain' (Stake 1991). Everett and Cox saw one plant on the shore at Widewater in July 1993. It is very rare in West and East Sussex.

Objective 2

To Maintain the Vegetative Shingle in Favourable Condition

Factor List

1 - The impact of recreational Use

Collect data, public use, recreation - Collect Data on the recreational use of the site

Attribute List

1 - The vegetative shingle plant communities

Collect data, vegetation, monitor - monitor the plant communities of the vegetative shingle

Collect data, vegetation, monitor - the presences of non-specialist vegetative shingle species

2 - The invertebrate communities

Collect data, other invertebrates, monitor - monitor the invertebrate communities associated with the vegetative shingle

Management Rationale

Shingles banks, barriers and spits are created when small particles (2-200mm) are washed up on to the coast either from undersea deposits, as with the south coast or from debris washed down rivers. These habitats are rare outside Northwest Europe, Japan and New Zealand. These shingle structures are inherently unstable with wave and wind action moving the shingle around the beach main in the form of longshore drift. Many of these shingle structures are very mobile and only a very ephemeral or strandline communities can form, however in some situations these structures will become more stable and a more complex vegetation communities will establish, as with the spits at Pagham and Church Norton. These plant communities are particular rare and are dominant by many pioneer species such as sea kale Crambe maritima, these species help retain the small particles and establish rudimental soils. Once these soils are established then other species will establish and soon a vegetative shingle community has developed. These communities will stabilise the shingle allow further succession but there is constant pressure from the elements and with one large storm the process can be started over again.

Other wildlife utilise the shingle, in particular shorebirds such as Ringed Plover, which breed in these habitats preferring the more open shingle. Also many species of invertebrates and lichen live in this constantly mobile ecosystem

There are a number of threats, both natural and man induced, which could effect the long-term survival of many of these fragile communities. The one thing that as land managers has little control over is the source of the shingle. One important factor, which continues the existence of many shingle systems, particularly those mobile ones, the supply of shingle from out at sea if this runs out then the shingle structure will move along the shore and in some areas will be lost. Manmade threats to these systems include the introduction of alien plants in particular garden escapes and the pressure of access to these systems. Garden escapes do particularly well as many are from the Mediterranean regions and thrive in dry conditions, which shingle banks represent. Access is also a major concern to these areas through compaction of the shingle, disturbance of shore nesting birds and enrichment through dog fowling

For some of the processes that control the character of the system management will have little or no effect as the forces of nature will move the shingle in ways it knows best, but many of the other threats can be managed and a mosaic of habitat can be maintain for the benefit of a wide range of wildlife.

Management List

1 - The control of non-specialist plant species

Manage habitat, coastal, by other activities - The removal of all non-specialist vegetative shingle species

Removal of all exotic non-native species and invasive native species

Feature 3 - Other Terrestrial Habitats

Description

Apart from the vegetative shingle two other distinctive grassland types form part of the margins to the lagoon. the first is located to the west end of the lagoon and consists of a dry grassland with tall species of grasses such as False Oat Grass. The other grassland is located centrally on the southern edge of the lagoon and is considerably wetter. This area is occasionally inundated when water levels or high.

Nationally notable species recorded:

Bembidion ephippium (ground beetle which inhabits open areas of saline mud near water)' recorded by P Hodge 1973: NOTABLE A status (lives on shore of lagoon)

Bembidion nigropiceum (ground beetle, normally recorded from rocky or sandy sea-shores near the high water mark): recorded by P Hodge in 1973: NOTABLE A status

Objective 3

To Maintain the Other Terrestrial Habitats (Grasslands)

Factor List

1 - The impact of recreational Use

Collect data, public use, recreation - Collect Data on the recreational use of the site

Attribute List

1 - The plant Communities

Collect data, vegetation, monitor - monitor the various different grasslands

Collect data, vegetation, monitor - monitor the grass sward length and quality

2 - The Invertebrate Communities

Collect data, Orthoptera, monitor - Monitor the Population of the grey bush cricket

Collect data, other invertebrates, monitor - monitor the invertebrate communities for the various grasslands

Management Rationale

Grasslands are a sub-successional habitat, which will tend to progress through scrub and eventually develop in to a woodland climax community. The successional processes on this site are particularly slow, probably due to the effects of salt spray from the coast and onshore winds inhibiting the growth of more scrub like plants that would progress succession forwards. Although not botanically rich, the site has an interesting invertebrate fauna including orthoptera of which the Grey Bush Cricket is Notable. If this habitat is allowed to progress to other succession stages then these grassland species of invertebrates may be lost. Mowing of the grassland takes place to ensure that it is kept in favourable condition with reference to the invertebrate populations. The grassland also provides an excellent habitat for the small mammal populations.

Management List

1 - The periodic mowing of the grasslands

Manage habitat, grassland, by mowing - the periodic mowing of the grassland in relation to the grass quality

mowing of the grassland takes place in September

Feature 4 - Regionally Important Bird Interest with particular reference to Ringed Plover

Description

Breeding Birds

Ringed Plover

The site normally holds between three and five nesting pairs. Ringed Plover, although not a schedule 1 species is protected under the Wildlife and Countryside Act 1981 through the provision of the basic offences, is listed under Annex II of the European Community Birds Directive and listed on Appendix II of the Berne Convention. It is also a Red Data species.

Widewater is the only location with more than one pair of Ringed Plover attempting to breed between Rye harbour to the east and Pagham/Chichester Harbour to the west. Widewater is therefore of regional importance for the species. However, breeding success is poor due to heavy predation by crows and disturbance by humans and dogs. It is questionable as to whether the breeding population at this site is viable - the birds are undoubtedly breeding in non-optimal conditions (and have been for a long time) and in terms of the national population the Widewater colony is insignificant.

Passage and wintering birds

The Widewater is considered to be of local importance for its passage birds. during hard weather periods in winter it also provides a safe roost for small numbers of sea duck and geese and is therefore considered of local importance for wintering birds.

Objective 4

To Maintain in favourable condition the populations of birds

Factor List

1 - The impact of recreational Use

Collect data, public use, recreation - Collect Data on the recreational use of the site

Attribute List

1 - The Population of summering and wintering Birds

Collect data, birds, survey - continue to compile records for the birds utilising the site

Collect data, birds, monitor - monitor the population of breeding Ringed Plover

Management Rationale

Ringed Plover and other shorebirds have become under intense pressure from the development and recreational use of their nesting areas. Widewater is one of the last remaining areas where suitable for nesting Ringed Plover between Shoreham and Bognor Regis. Unfortunately due to the present recreational pressure on the site the majority of the attempts are failing. It is considered that some effort should be made to reduce disturbance by fencing the main breeding area. There was an attempt to fence the vegetative shingle to protect the Ringed Plover breeding areas, however the fencing suffered from human interference, despite the production of educational materials. It is planned to research other possible protection methods however if these prove to be unsuccessful it must be a consideration that the site has become unfavourable to this species and recovery as impossible.

Management List

1 - Protection of the Ringed Plover breeding population

Manage species, bird - Protection of Ringed Plover Nests

Feature 5 - Recreation, education/research and amenity (All Site)

Description

There are two very large car parks adjacent to the Widewater, which are situated, adjacent to the beach at Shoreham. The majority of people who visit the site probably do so not because Widewater is there, but because there is good access along the sea front where people can walk, jog, cycle, etc. People visiting the beach, including summer tourists, local people and windsurfers, also use the car parks. Some of these people picnic on the grass of the shore of the Widewater, but in the main most of them appear to stick to the promenade and the beach (pers. obs. S. Everett 1993). Dog walkers do venture on to the shore of the lagoon but it is considered that most of them do so to encourage their dogs to foul away from the car park new poop scooping is required. The amount of dog walking along the lagoon shore has not been quantified but local Widewater residents consider that it is a problem.

The Widewater is obviously a very important landscape and amenity feature for people who live next to it.

People who visit Widewater specifically for what the lagoon and its basin can offer are, probably, mainly birdwatchers. The site is very popular for birdwatching, wading birds being very easy to see from the car parks.

There are three interpretative boards situated on the lagoon bank. These provide summary of the site's nature conservation importance and so have an important role to play in raising general awareness about nature conservation in the area. No evidence has been received it is used for field studies by local schools, but the Widewater itself has been the focus of a number of research projects many of them carried out under the auspices of Southampton university's Department of Oceanography. Such long-term research as has been carried out at the Widewater is unusual. The data bank built up is therefore considered to be nationally important and the continuation of such research and monitoring at the site should be encouraged. The site is considered unsuitable for school field trips (i.e. intensive fieldwork) but could form the focus for curriculum-based projects (e.g. geography and science, looking at the conservation problems of the Widewater and its importance in a local, regional and national context).

The general appearance of the site leaves much to be desired. Some rubbish appears to be permanent. The prevalence of lumps of concrete old jetties and rotten crumbling timber revetments adds to the general untidy appearance of the site. The embankment below the promenade and the western car park has also been sporadically repaired each time with different materials!

Taking this information into account, the site is therefore considered of local importance as an amenity and educational resource and of national significance as a research site into the ecology of saline lagoons.

Objective 5

To maintain the area in a suitable conditions to provide an area for a recreational and educational resource for the local community

Management Rationale

The site provides an excellent resource to allow various levels of educational establishment to utilise. Being suitably placed within a dense population centre the location makes it easy accessible. At present it is probably under used and encouraging use by local establishments made raise the profile of the site and the more considered usage.

Feature 6 - Administration of the Area

Objective 6

To ensure that effective administration procedures are in place

Management Rationale

This to ensure the smooth running of the reserve and that all legal requirements are met.

Management List

1 - Carry out the administration required to meet legal requirements

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