Coastal
Zone
WIDEWATER
LAGOON
Brackish
Water Lagoon
|
Overview
Widewater
is a landlocked brackish lagoon approximately 1066 metres long and 90 metres
at its widest point when the lagoon is in flood. It was created by Man
from the original Adur
estuary after been landlocked by longshore
drift and violent storms. The waters are replenished by the sea, which
filters
up through the basin of the lagoon on very high tides, and also by
rain water. There is a dramatic rise in the level after heavy rainfall,
more than can be explained by the rain landing directly on the lagoon flood
plain. Man has built up banks on the perimeter of the lagoon to prevent
flooding to this nearby reclaimed land, now turned to residential use.
The quantity of water contained within the lagoon and
salinity
are liable to fluctuate wildly. The flood plain covers an area of 18.5
acres.
At
its maximum flooding with a measurement on the gauge by the bridge giving
a depth of 1.60 metres, the lagoon will cover an area of 4.6 hectares (=
11.4 acres) with a perimeter of 2282 metres.
Wildlife
Reports
Widewater
Wildlife Reports 2006
31
December 2005
The
Redshank
is called the "Sentinel of the Marshes"
because it is the first bird to all out a warning at the approach of danger.
For this reason Ray
Hamblett did well to get close to this
Redshank
feeding in the shallows of Widewater Lagoon.
Lancing
Nature Notes |
|
19
December 2005
On
the high (5.49 metres WX Tides at Shoreham
Harbour) tide in the early afternoon (about
2:00 pm) the water bubbled up through the
floor of Widewater Lagoon sending circular ripples
over the surface of the clear water.
The
Sun was low in the sky giving a yellow cast. The Little
Egret was actively fishing snapping at
small prey, probably the prawns, although none were actually seen in the
shallow water.
|
Any
signs of flowers in December in any habitat is unusual. A single yellow
remnant of a Mayweed
flower was seen amongst the creeping green stems over the gravel flood
plain. |
30
November 2005
A
flock of at least half a dozen Teals
were feeding in their characteristic way, all upturned and rear showing,
on Widewater just west of the bridge and causeway.
With
the usual Black-headed Gulls and Mute
Swans, there were a flock of nearly a
hundred Dunlins,
three Little Egrets, one Oystercatcher,
at least two Redshanks
and probably five or more, and one Turnstone
was seen camouflaged trotting along at the water's edge over pebbles (lower
down the shore than a patch of purple Glasswort).
28
November 2005
A
Kingfisher
was seen at the western end of Widewater Lagoon.
Report
by Russell
16 November
2005
Just
after midday there were three Little Egrets
seen on Widewater, but no Cormorants.
13
November 2005
There
were fourteen Cormorants
seen on Widewater including one actively diving under the water on the
flooded lagoon. There was a chirm of just
four Goldfinches
in
the remnants of vegetation between the lagoon and the shore.
12
November 2005
Another
Grey
Phalarope was seen and photographed at
the western end of Widewater Lagoon, Lancing until early afternoon when
it flew off. Also two Black
Redstarts
and a late Wheatear
on the beach.
7
November 2005
There
were at least eleven Cormorants
and two Little Egrets
on a flooded (1.64 metres)
Widewater. I do not think this represents a population increase but a movement
of the 29 birds that are usually to be found
on the beach a mile to the west on the beach by Brooklands.
The immature birds had white bellies.
4 November
2005
Seven
Cormorants
were perched on poles in Widewater Lagoon east of the bridge, but flew
to the west of the bridge when disturbed.
The
six large mushrooms (illustrated above) grew
in the grass between Widewater Lagoon and the sea, east of the bridge.
They had already been broken off before I photographed them. The cap diameter
of the largest specimen was roughly measured at about 15 cm with a height
of an estimated 15 cm. This looks like one of the Agaricus
species (a genus that includes many edible mushrooms).
Previous
Report
28
September 2005
Four
Little
Egrets actively fished in the shallows
of the flooded lagoon, with one Cormorant
seen diving underneath the surface, another flying at low level and two
perched on the seaward pole of the pipeline.
27
September 2005
Six
Cormorants,
four Little Egrets
and one Grey Heronwere
all seen fishing in the lagoon.
Report
by Derek Neatre
23
August 2005
At
least one 3-spined Stickleback
was seen in the shallows of the flooded lagoon. There were a few small
prawns,
but not the hundreds that are often seen. There was what appeared to be
a handful of small midges
(Chironomidae) skating on the shallows near the Tamarisk
east of the bridge. These midges could be Clunio
marinus.
Over
dry land there was a male Common Blue Butterfly.
12
August 2005
The
unmistakable white rump of the Wheatear
was just confirmation of at least three birds by Widewater about to embark
on their long migration south for the winter. The
lagoon was in flood with very little bird life, except for the Mute
Swans and
the four cygnets.
27
July 2005
The
lagoon was in flood after the recent high tides registering 1.64
metres on the gauge and was still like a mill
pond. The water itself was discoloured slightly black, probably from the
sediment churned up in the breezes and soil washed in during the rain in
the last two days. Around midday the lagoon was covered in mist so the
flats at the east end where completely obscured when viewed from the bridge.
The
air temperature at the time was 18.8° C with a humidity of 92%.
The
Mute
Swans still had four
cygnets and at least one Little
Egret was fishing. The first photograph
from the left shows the Tamarisk
on a small island and the two central images contain plants to be identified.
5 July
2005
Four
cygnets
are observed with their Mute Swan
parents on Widewater Lagoon. The previous offspring of seven and six cygnets
respectively all perished earlier in the year. At least two
Little Egrets were feeding in the flooded
lagoon.
29
June 2005
The
lagoon was flooded again and all the muddy margins were covered with water.
As it had not rained the water must have come in either through the pipeline
or percolated through the shingle floor of the lagoon. Viper's
Bugloss and Yellow-horned
Poppy were in
splendid flower mostly between the concrete path and the wooden fences
preventing the shingle beach from spilling over the path by the gales.
20
June 2005
Shore
Crabs, Carcinus
maenas, were observed dying in isolated pools in Widewater Lagoon.
Report
by Derek Neate (FOWL)
With the
low level (0.27 metres) of the lagoon, the patch of water by the inlet
pipe became isolated from the main body of water. In this puddle the salinity
was recorded at a hypersaline 42.8‰ after two weeks of warm weather (air
temperatures over 24° C and over 27° C) and a water temperature
of 30.2° C. The main body of the lagoon registered a salinity of 37‰.
(The conditions were favourable for evaporation.)
Readings
by John Knight (WSCC)
Widewater
Salinity Page
These
two events are probably connected. In June (in Sussex) the Shore
Crab moves in estuaries and into lower salinity
water than the sea. The crabs will be able to enter when small via the
pipeline. In water temperatures of over 28°
C or with a salinity over and above natural
seawater at about 34.5‰ this
crab has been known to leave the water and perish if it is unable to find
a favourable niche. (The conditions are outside its natural amplitude for
survival.)
18
June 2005
The
lagoon level showed plenty of mud with the tide level down to 1.3
metres on the gauge. The water was brownish-orange
in colour and there was no immediate observation of thousands of prawns.
Widewater
Flood
Plain
Stonecrops,
Sea
Heath, Bird's
Foot Trefoil,
Ivy-leaved
Toadflax,
Viper's
Bugloss,
Opium
Poppy, Sea Kale and Sea
Campion were prominent.
There
was a mating pair of Common Blue Butterflies
on a long grass.
Adur
Butterfly List 2005
Sea
Heath, Frankenia
laevis,
& Lesser Sea-spurrey, Spergularia
marina.
The
flood plain revealed Glasswort
still in a zone before the mud with a salt
marsh grass and a plant with small white-mauve
five petalled flowers (image on the right, above) which I have identified
as the Lesser Sea-spurrey, Spergularia
marina.
Widewater
Salt Marsh
13
June 2005
There
were plenty of muddy margins
on the receding lagoon on the neap tides. Even the Little
Egrets were absent on a passage visit.
29
May 2005
Bird's
Foot Trefoil was looking colourful on
the Widewater flood plain and Yellow-horned
Poppy between the concrete path and the
wooden fence that borders the pebbled beach. A very small blue butterfly
fluttered over near the Church of the Good Shepherd. It was most likely
a Common Blue Butterfly.
28
May 2005
I
noticed both the occasional taller White
Campion near the concrete path and the
very common ground-hugging Sea Campion
on the flood plain. Tree Mallow
was in flower but this is on the beach margins at the extreme western end
of Widewater near the Sailing Club. There does not seem to be any new growths
of Tree Mallow.
Tree
Mallow Images
25
May 2005
There
were five Little Egrets
fishing in a flooded Widewater Lagoon just before dusk (the current spring
tides
are over 6 metres) but I did not spot any
Mute
Swan cygnets (although I could have missed
them). The muddy margins were all under water, which was partially covered
by a green floating fluffy weed.
23
May 2005
On
Widewater Lagoon, the Mute Swans
at the eastern end are looking after six cygnets.
Report
by Derek Neate (FOWL)
21
May 2005
A
Gull-billed
Tern,
Sterna
nilotica, is reported from Lancing beach over Widewater. This is
a rare bird in Britain and Sussex.
18
May 2005
It
was the neap tides cycle and the Widewater water
had receded leaving the muddy margins (which may allow Glasswort
to grow). Three Little Egrets
were seen. One Ringed
Plover demonstrated its distraction display
on the gravel near the pipes on which the wild plants
(e.g. Thrift, Ivy-leaved
Toadflax, Sea
Campion, Bulbous Buttercup)
flowered amongst the Stonecrops.
c.16
May 2005
Seven
Mute
Swans cygnets are found dead and without
injury on Widewater. The speculation is that the cygnets died because of
kidney damage through drinking sea water. (This
explanation seems unlikely to me AH.)
Report
by Derek Neate (FOWL)
11
May 2005
Two
adult Mute Swans
are seen guarding their seven cygnets on Widewater Lagoon.
10
May 2005
Thrift
was now flowering amongst the Ivy-leaved
Toadflax, which seemed much more extensive
this year. The first yellow of the a occasional patches of Bird's
Foot Trefoil began to appear.
4 May
2005
Despite
the neap tides, Widewater was still in flood providing
a home for at least 23 Mute Swans
and at least two Little Egrets.
If this depth of water is maintained the new growths of Glasswort
would be impeded.
The
gravel and pebble verges near the pipeline were covered in Ivy-leaved
Toadflax with clumps of Sea
Campion and Sea
Kale.
25
April 2005
On
the sea by Widewater, there were two Great
Crested Grebes and two Sandwich
Terns were flying over the sea
and diving. Immigrant Wheatears
were
on the grass by the brackish water lagoon.
There
were four Little Egrets,
at least one very actively feeding, stabbing at prey in the flooded lagoon.
Both the Little Egret
and the single Turnstone
were disturbed in the photograph above.
20
April 2005
Despite
the neap tides, Widewater was still extensively
flooded with most of the Glasswort
muddy margins submerged at a gauge reading of 1.47
metres. With thousands of prawns
this was an ideal feeding ground for four or five regular Little
Egrets.
12
April 2005
Five
Little
Egrets fished in the flooded lagoon (1.59
metres). One Little
Egret caught and swallowed what, because
of the flash of silver, looked like a small fish. Two Turnstones
(in winter livery) patrolled the shallows.
The
salinity
near the bridge was 33.1‰.
Widewater
Lagoon Management Meeting at Lancing Parish Hall
The
new draft Management Plan is in the process of being drawn up. I cannot
see any problems as nature has got the upper hand over any changes that
the operation of the pipeline can make.
My
Brief Comments (Link)
26
March 2005
Three
Little Egrets fed energetically and frequently
(up to every 15 seconds), probably gobbling up small prawns, in the shallows
of the flooded Widewater Lagoon.
The
yellow in the foreground are Daffodils.
14
March 2005
Widewater
was as still as a millpond apart from the torrents of seawater gushing
through the pipelines on the equinoctial spring tide
and the seawater bubbling through the shingle bank (the bubbles could be
seen on the surface of the lagoon) through the lagoon mud substrate. The
depth gauge registered a high 1 metre 60 cm.
There was no moving life like the small prawns to be seen in the clear
water.
Mallards
landed on the surface and a Little Egret
probed around the flooded edges.
19
February 2005
There
was one Brent Goose on
Widewater.
17
February 2005
There
was a Stonechat
in the bushes around Widewater and a Little
Grebe on the lagoon.
8
February 2005
The
lagoon level had dropped to one of the lowest since the pipeline was installed.
The
gauge read 1.36 cm (above Chart Datum?). The
explanation was a lack of rain in January.
Salinity
is now measured by John Knight of West Sussex
County Council using an electronic meter that
recorded 26‰.
WSCC
Environmental Monitoring at Widewater Lagoon 2004 & 2005 (Link)
There
was a large mushroom with a 30 cm diameter on the
grassland to the east of the bridge over Widewater Lagoon. Unfortunately
it had been broken up. It looked like an unattractive specimen of an Agrocybe.
At
least two Redshanks
and two Little Egrets were
actively feeding in the shallows.
Lichens
grew on wooden fences, there was plenty of niches for epixylic
organisms despite the paucity of trees on the beach. .
Link
to Widewater Reports 2004
Adur
Coastal 2004
Adur
Nature Notes 2005: Index Page
|