The Walton Backwaters Experience - Survival in the Balance

Main >> Education & Research >> My Research Page

Coastal Erosion Naze Notes - The Walton Backwaters Experience - Walton-on-the-Naze

~ Survival in the Balance ~

TOWNSITE

HOMEPAGE

_______________________________________________________________________________________________________________________________

WALTON BACKWATERS | SAILING TO THE BACKWATERS | BACKWATERS - VANISHING POINT | BACKWATERS - STORM WARNING | BACKWATERS TALES

Living on Borrowed Time...

STORM SURGE 2007

Photo Gallery

Life Cycle

of the

Backwaters

Spring

As the weather turns milder, the resident bird community of the Backwaters is joined by warm-weather visitors - like the little tern - and breeding starts in earnest! The little tern only nests on shingle beaches, like those near Stone Point, and these sites are therefore seasonally protected. Redshank and shelduck nest on the saltmarsh, risking equinoctial high tides. Many ducks use the dykes and ditches of grazing marshland. The area is a stopping off place for waders from southern Europe and Africa heading for breeding grounds further north. They are easily spotted in late spring with their bright new plumage ready for the summer.

Summer

Young birds are �on the wing� feeding on the mudflats under parental supervision. By July, the saltmarsh becomes alive with a blaze of colour as the vegetation flowers into the pale mauve of sea lavender, punctuated occasionally by the blue of sea aster and the yellow of golden samphire. By August the first bird migrations head south. The indigenous colonies of grey plover and redshank demarcate their feeding territories for the coming cold weather.

Autumn

The Backwaters become a stopping-off point for migrating birds. Kestrels can be seen catching water voles on the saltmarsh. Food is now plentiful, so many birds take this opportunity to moult and grow new feathers - a process that uses up huge amounts of energy - before moving on to winter quarters. On the mudflats, the samphire turns to golden-red. With the approach of winter, the brent geese arrive to feed in the eel-grass before moving on to graze coastal fields.

Winter

This is the time when the Backwaters are at their most crowded with birds. The area supports a total population of over forty thousand! Late arrivals fly in from Europe�s Wadden Sea. Shelduck and redshank will brave the cold to make their courtship displays and pair up ready for spring breeding. February is an especially good time to watch the birds of the Backwaters. Even those seabirds that are planning their migration north to breed often pair up before flight � in full breeding plumage display.

_______________________________

MONTHLY INFORMATION

NATURE WARDEN'S REPORT

WARDEN'S BIRD COUNT

___________________________

The Walton Backwaters represents the largest area of estuarine saltmarsh on the Essex coast � a soft sedimentary habitat in a largely flat alluvial landscape. Due to the unique system of localised longshore drift (prevailing tidal current), erosion becomes a huge problem to coastal stability - and to environmental survival.

Long-

shore

Drift:

Essex

Coast

click on

the image

for full report

The picture (above) illustrates this local phenomenon (source Barne 1998). The normal drift along the east coast is from north to south. Just below the Naze in the top half of this picture the arrows go in both directions. This is because of the physical nature of the Walton Backwaters. The estuary was formed within in a short, broad London Clay basin just after the last Ice Age, about 11,000 years ago (Holocene Period). The short length (7 km) of the main water course within the Backwaters - Hamford Water - means that there is, as a consequence, very low tidal force at the mouth of the estuary, unlike the much stronger ones in other east coast rivers like the Yare, Ore, Deben, Stour, Orwell and Blackwater. As a result, longshore sediment transport along the coast moves material northwards from the Naze to form the sand spit at Stone Point and extending to Pye Sands. The development of this spit over the last few thousand years has - until recently - resulted in the entrance to the Walton Backwaters being reduced from 3.5 km to 2.1 km. This restriction has allowed for the development of extensive salt marshes on either side of Hamford Water � far more so that in other Essex estuaries.

The uniqueness of the area can be seen when comparing the north-pointing Stone Point spit with those formed by other estuaries in the region: Yarmouth spit at the mouth of the Yare, Orfordness on the Ore, Languard Point at the Harwich entrance and the mouth of the Deben - all these point south, aligning themselves with the prevailing drift of sediment transportation for the region.

The anomaly of the northerly flow of sediment at the Naze has, in recent years, caused huge problems for the future survival of the Backwaters. Referring back to the picture, on the top right hand side is a line that marks the deep water Harwich Ship Channel. The black triangle indicates sediment sink at this point as all the south flowing material that should have supplied the beaches around the Backwaters is forced into this dredged channel and out to sea. All that the spit at Stone Point has for a supply of beach material is the northerly flow from the Naze, but because this is such a very short length of coastline there is precious little sediment to deposit. The result is that ever since the Harwich Harbour dredging was started, Stone Point spit has started to diminish, thus allowing the Backwaters entrance to widen and put the saltmarsh habitat at grave risk.

Man�s natural reaction to sea erosion is to protect the land at risk. During the 18th and 19th centuries land reclamation reached its peak and the Backwater�s Horsey Island was enlarged as a result. Today, man has reclaimed nearly half of the Essex coast intertidal estuaries that existed 2000 years ago. Sea walls are now a common sight on the Essex �coastscape�. However, this has contributed to further problems for the survival of the Backwaters habitat. With man�s �double whammy� of damming off sediment that would naturally be carried back to the shoreline, and of dredging out sediment from the Harwich Channel that would naturally end up on the coast, he has created the phenomena known as �coastal squeeze�, whereby the natural protective coastal barrier is deprived of beach material from both land and sea. As a consequence, the coastal environment suffers drastically as it is squeezed into an ever diminishing area. All this at a time when the rate of sea level rise is predicted to increase from 2mm. per year now, up to 8-12mm. per year during the next half century!

This is why the survival of the Backwaters hangs in the balance. Unless action is taken very soon, the whole area will disappear as an ecological system. It will turn from fertile wilderness to barren desert.

Net loss of its saltmarsh between 1973 and 1998 was 29% (source: Coastal Geomorphologic Partnership 2000). This rate is accelerating all the time. Between 1973 and 1988 the annual rate of erosion was 0.8%; between 1988 and 1998 this had doubled to 1.6% (source: Cooper 2000). Extrapolated results show that if nothing is done, the Backwaters saltmarsh will be gone completely in thirty-five years (source: tabulated figures from the Essex Estuaries Coastal Habitat Management Plan 2002).

Walton

Backwaters

Beach

Recharge

Sites

Naze

AERIAL

PHOTO

Gallery

click on

the image

for full report

With the retreat of Stone Point, Horsey Island has become increasingly vulnerable to wave attack. In 1988 a barrage breakwater of sunken barges was put in position. Since then, in a near-desperate attempt to �hold the line� nearly half a million cubic metres of material dredged from the Harwich deep water channel has been deposited to the north and south of the Walton Backwaters entrance and onto the vulnerable northeast corner of Horsey Island (see map above) during the past fifteen years (source: Environment Agency 2005). Due to natural wave action, much of this material had simply been carried back out to sea!

The bottom line to all this is the simple and inescapable fact that the policy of costly hard seawall defences that �protect at all cost� will have to be replaced with one of �realignment', which accepts that some land will be lost in the interests of natural survival.

Either that, or wave goodbye to a whole ecological system... and the time for making decisions is fast running out.