Monthly Archives: May 2018

29th May, 2018. The example of Holland (clay banks continued). Also Kilnsea Visitor Centre.

Having considered Sunk Island the authors of Tidal Lands then describe the clay banks of ‘Holland’ in some detail.

The background to this is that about 50% of the Netherlands is below one metre above sea level, 28% being below sea level. The techniques of reclaiming coastal lowlands have been pioneered by the Dutch since the 1500s, reclaimed areas being known as ‘polders’. 17% of the area of the Netherlands is polder land. In 1932 the marine inlet known as the Zuider Zee was blocked-off from the North Sea creating the Ijsselmere lake much of which has subsequently been reclaimed to polder-land totalling 965 square miles. The Netherlands is therefore particularly threatened by climate change and rising sea level, the picture above (taken from the internet) portrays the ‘Christmas Flood of 1717’.

Recently went for ride to Kilnsea at the head of Spurn Point at mouth of the Humber Estuary. Although didn’t go for this reason decided while there to go see the controversial new visitor centre built by the Yorkshire Wildlife Trust in the area. The building is raised on stone-filled casions in case of flood but also to give views of the Humber, of the spit itself and out to sea. The building itself was stark but functional and the immediate surroundings need time to flourish (shrubs etc just recently planted). It is generating a great deal of interest and loads of people were in the area. Sadly the café at Kilnsea has closed, this probably related to competition from the one at the new visitor centre. Very little remains of the Second World War gun emplacement at Kilnsea, a victim of coastal erosion.

The Y.W.T. visitor centre at Bempton, north of Bridlington, is much nicer but did not have to be built with flooding in mind, being on land above some of the highest, most resistant, cliffs in England. They have loads of bird feeders but I saw none at Kilnsea.

28th May, 2018. ‘Slob land’ (clay banks continued).

‘This art (the ‘inning’ of saltings and coastal marshes) is coeval with civilisation’ (Tidal Lands, p.121). The authors use the interesting term ‘slob land’ to define un-reclaimed coastal lowland marsh land (often saltmarsh) – whether the word ‘slob’ was first used in its human context or environmental context I have yet to find out, in neither context is it complimentary. The authors then describe warping as an early means of reclamation, which seems odd. However, rivers where flooding regularly occurs built up a natural river bank, the authors explain this with an interesting fact ‘brick earth (silt/fine clay particles) in suspension will sink at a rate of about 7 inches per minute, sea sand in the same period will sink about 12 feet’, in other words silt will be carried inland while heavier particles will be deposited early and bond to build-up a river bank (levee). Warping is a man-made system whereby any receding waters are trapped, deposit their silt and then the water drained away by a network of drainage ditches. Silty soils are very fertile and repay the costs of warping with increased yields of arable crops or richness of pasture (see Hull in the beginning, pdf/publications). The authors highlight simple clay banks or ‘faggots or fascines’ as the means of containing the flood water on the land, the latter being bundles of small timber or brushwood tied by osier twigs (for a completely different use of fascines see pdf/publication Sidney Walter Clarke – Great War service in the Tank Corps).

One example given by the authors is of Sunk Island on the south coast of Holderness, East Yorkshire. By 1744, they claim, 1560 acres had been embanked with further extensions given and consequent rises in land values up to ‘at this time’ (1910s) 6600 acres had been reclaimed. Other British examples of foreshore reclamation in Southampton Water and the Fens were briefly covered before the authors considered the situation in the ‘Kingdom of Holland’.

(to be continued).

27th May, 2018. Clay banks (continued).

With being published in 1918 Tidal Lands (s.p.b.s) considers the reclamation of lowland foreshores to be an automatic good (waste land made productive), nowhere do the authors hint at any sense of loss when changing the shoreline ecosystem. The photo above (p. 167) shows the vegetated ‘high saltmarsh’ being grazed by horses and, in the foreground, the sparsely vegetated ‘low saltmarsh’, this reminding that the natural saltmarsh of lowland coasts is not killed-off by grazing but is by over-grazing. Today a different perspective prevails in that saltmarsh is a rapidly declining ecosystem with some protection in law. Along the Humber Estuary foreshore any loss of saltmarsh from industrial development has to be compensated by the establishment of more saltmarsh in another location in the region, planning permission relies on this understanding with the Environment Agency overseeing the process. Furthermore in the revised flood management scheme areas of ‘managed realignment’ are areas of potential colonisation of saltmarsh.

Saltmarsh is really a collective term for a certain ecosystem/local environment. For example the caption for the above picture from Tidal Lands records that on the ‘high saltmarsh’ two types of plant are growing Glyceria maritima and Armeria maritima, while on the ‘low saltmarsh’ patches of Suaeda maritima are growing – this along a section of the coast of Belgium.

25th May, 2018. Returning to ‘clay-banks’.

Of course not all linear flood defences are just banks of clay soil. For example, yesterday had a short walk along the ‘bank’ at Goxhill Ferry, with very clear views along the Estuary frontage of Hull, here the seaward slope of the bank is reinforced with natural stone blocks laid to fit together then bonded by a layer of some bitumen material. If this reinforcement was created post 1953 floods, as were many along the East Coast, then it has lasted very well (at a different point along the bank between Barton and South Ferriby where an un-bonded stone slope was created the force of the swirling ebb tide has dislodged a couple of facing stones with the result that the clay below is being eroded away and surrounding stones have become unstable, thus a very weak point in the bank is being created).

Most of the Humber Estuary ‘bank’ is blocking the waters from flowing across the lowlands behind as the waters did in prehistoric and geological times. The picture above shows the point on the south bank where there is a natural flood defence Ferriby cliff. Here a 20 feet high boulder clay cliff blocks ingress although it is quite readily undercut by spring tides this leading to cliff retreat (this feature is replicated on the north bank in the parish of North Ferriby). The picture, by the way, is Fig. 4 in the Geology pdf on this website). Beyond the trees begins the lowland coast of the Vale of Ancholme so here the linear man-made flood defence begins again.

So linear man-made flood defences in lowland coastal regions are a challenge by Man to Nature, who is the greater, a struggle that in the era of climate change sees Man on the back-foot. The message in Tidal Lands (s.p.b.s), published 1918, was more positive on the side of Man – it can, and should, be done.

23rd May, 2018. Pernicious and invasive plants.

An informative site re the above is Gov. UK – Environmental Management – Wildlife and Habitat Conservation (this jointly published by Natural England, Environment Agency and Department of the Environment). Although persons can be fined or imprisoned for allowing pernicious weeds to spread from their land to that of a neighbour or into ‘the wild’ it is hard to see how this could be proven.

Legally defined pernicious plants include; common ragwort (see above, single plant), spear thistle, creeping or field thistle, broad-leaved dock and curled dock. Ragwort is poisonous to farm animals (however, in Norfolk, back in the day, it was normal to see ragwort in pasture-land having been grazed around but not touched by cattle). To get rid of today it can be sprayed, removed, cut back (so no seed dispersal) or spot burnt. Spraying or disposal have to follow a legal framework.

Examples of ‘harmful, invasive species’ are; Japanese knotweed, giant hogweed, Himalayan balsam, rhododendron ponticum and New Zealand pigmyweed. There are, apparently over a thousand species of rhododendron, originally native to the Himalayan foothills, but the nectar of ponticum is poisonous, as with honey made from it, and it causes the death of bees alighting on the flower. Apparently rhododendron ponticum was a pre-glacial native shrub but didn’t naturally re-colonise after the last Ice Age, an interesting example of ecological archaeology. Harmful invasive species should be sprayed or burnt (although for giant hogweed the spraying has to be repeated for 15 years to eradicate seeds that may lie dormant). North Lincolnshire Council sprays Japanese knotweed when notified. Burning, spraying or disposal have to be done with the guidance and legal requirements of the Environment Agency.

A tv. programme on customs officers in Australia highlights their determined efforts to keep-out possible invasive plant species.

Yesterday = blog and research am + dental check-up and hygienist. Pm Hull – St. Andrew’s Quay, Queen’s Gardens and Queen Victoria Square with R. and M. Fine, high pressure weather, v. hot if sheltered from n.e. breeze.

22nd May, 2018. Cow Parsley.

Firstly a mistake, the woad on the Humber bank is more likely to be yellow rocket, Barberea vulgaris, associated historically with a young Greek woman, Barbara, killed by Roman soldiers in A.D. 235 and later canonised by the Roman Catholic Church. Vulgaris = common (‘of damp places and riversides’).

The above picture is taken (internet) from a German 19th century ‘herbal’ published by Franz Eugen Kohler (1834-1879) but written by number of authors including Herman Adolph Kohler, an exact contemporary of F.E.K.

At some point the plant was introduced into U.S.A. resulting in the State of Washington, for example, declaring it a ‘Noxious Weed’, making it a criminal offence to knowingly sow or distribute it. The equivalent term in Britain is ‘Pernicious Plant’. Usually the reason for such a definition is that they are poisonous to farm animals or humans or both. However, some poisonous plants are not so defined and some are defined as pernicious because, left unchecked, they smother-out all other plants.

Apparently cow parsley was also historically known by the sinister term ‘mother-die’, possibly because the carrot-like roots are semi-poisonous. Cow parsley is an ‘umbellifer’, that is a plant whose flower heads form ‘umbels’, clusters of small white flowers which together form an umbrella like shape. Other umbellifers are poisonous, particularly hemlock, the sap of which is said to have been the preferred poison of the Romans.

(Will get back to clay banks soon).