The Wash Dam

Sketch Plan from 1965 Wash Barrage Proposals

The first plan for a dam across the Wash was published by John Rennie the Younger in 1837 with its purpose to improve shelter for mercantile  marine in storms, improve the maintenance of drainage of the fens and to reclaim agricultural land from the sea. The magnitude of the proposed engineering works was huge and to many quite scary. In 1840 he sought to have his plan reviewed by second experts with costings. One plan to straighten out the four rivers leading into the Wash leading them into one channel was costed at £1,100,000 (about £150,000,000 in 2026 value) or an alternative smaller channel and dam at the junction of the Ouse and the Nene costed at £600,000.

The plans were reviewed and indorsed by renowned engineers Mr. W.C. Mylne and Robert Stephenson. Robert Stephenson commented  revealing some of the challenges as follows:

“Too much reliance must not be put upon ancient plans, which afford very uncertain data. When old charts of the Wash are compared with new ones, generally speaking the advance made by land on sea would appear very small in later times, and the ratio of progress extremely slow, but it is not correct to assume from this circumstance that a rapid accession of land may not be made to take place by artificial means. The comparison of the old and new maps only goes to prove that the ebbing and flowing of the tides, in conjunction with the rivers flowing into the Wash have attained the conditions necessary to equilibrium, or in other words that the action and the reaction of the waters are all but equal, whence the deposit appears to accumulate slowly.

But alter by art, or remove some of these conditions of equilibrium, and instantly new series of causes come into play. Sand banks may be shifted, and a more rapid increase of deposit may be made to take place. What can be more striking than a singularly rapid deposit which is daily forming behind the banks that were extended seaward for the purpose of guiding the River Nene? These banks, although they appear to perform only one important office of conducting the stream into deep water, do in reality achieve another not less important, when we look at the creation of land, by accelerating the deposit. The stream of river on the ebb tide no longer spreads out into  a wide basin, interfering with and carrying away any sediment which may have fallen from the waters of the previous flood tide during their quiescent state. The projecting channel bank prevents, in fact, the momentum of the descending tide being absorbed and wasted upon the adjacent shallows and at the same time entirely shelters those shallows from scour, the tidal waters on each side of the protected channel being nearly pounded up, and quite uninfluenced by land streams will remain for a longer time in a state of quiescence and the recession of the water will be less rapid – conditions obviously calculated to accelerate the deposit of silt.

The area over which these favourable circumstances extend is, of course, confined, in the first instance, to a narrow belt around the shore, and the marginal line thus formed would scarcely be exceeded, except at the rate shown by the old charts. But the moment this belt is raised by silt to the level of high water neap tides, it may be enclosed by an advanced bank, and a new shelf created outside, which accomplished, another silt will begin to accumulate as before, when the process of further embanking will have to be resorted to. The operation must be gradual, in patches of 500 or 700 acres at a time, which experience shows to be the most manageable in closing a sea bank, by requiring only such a gap for the reflux of tidal waters to be left in it within engineering power to stop by economical means. To attempt an immense inclosure from the sea, per saltum, is futile, as witness Lough Foyle; to proceed by degrees and successfully is proved – witness the Forth on both sides; Grangemouth and Kincardine, or the Humber on its northern bank.

The material for making the land exists already, without addition to it, in abundance for the work; it can be so accumulated as to become capable of cultivation. Only create bays or pounds, quiet-water places where the matter in suspension or in motion by the undercurrent may deposit. The time for enclosure must be chosen with judgement, as a premature enclosure is not only more costly but yields an inferior soil. The high-water mark of neap tides, or a little above it, seems to be the proper time for embarking on this estuary.”

Thus we see the earliest viable plan, although it did not come to fruition sowing the seeds for future proposals.

In December 1893 Mr. Brand M.P. for Cambridge and Wisbech sought to revive John Rennie’s 1837 proposal, but this was not welcomed by the Chancellor of the Exchequer on the grounds of cost. Up to the early 1920’s any focus was upon the creation of agricultural land. This did not necessarily involve a dam across the Wash per se but rather embankments or channels over time to create accelerated silting of the tidal areas increasing the height of the marsh until it could be cultivated. It was acknowledged over time that this could see a bridging of the gap between Gibraltar Point and Hunstanton.

1928 saw a different proposal – the damming of the Wash to enable tidal action to generate electricity.  The proposer of this scheme was Mr. Leonard Weaver who formed the Dynamic Electrical Co. Ltd to raise money for his proposition, “to construct the necessary engineering works for the conservation of a portion of the tidal energy of the Wash Basin and to turn the same to account in the production of cheap electrical energy.”  The Company sought to raise £100,000 in 1 schilling shares available to the public to provide the necessary funds to complete the ground surveys, obtain additional reports for submission to the Electricity Commissioners, to pay the cost of underwriting  and issuing later the construction capital proper. The prospectus claimed that the power of the sea “is regular and unfailing. The ebb and flow are said to be accurately known and the daily load curve can be definitely arranged without fear of failure.”

The scheme was ambitious proposing the conversion of the Wash into an inland lake 125 miles in extent and a dam with a road on top linking Skegness with Hunstanton. The area was to cover 31,500 acres of which 22,500 acres would be level basin always full of water at high tide level and 9000 acres would be low level basin which would always be at low tide level and consequently would provide an unfailing fall of 15 feet of water between the two basins. The two basins would be divided by a dam upon which would be built a power house containing the turbines. The whole scheme was costed at £4,000,000 (£326 billion in 2026 value).

Unfortunately the scheme was full of holes and subject to much valid criticism as it did not stand up to scrutiny in several areas:

Mr. F. Sanderson Robins M.Inst. C.E., chartered civil engineer, using tidal readings taken in August and September 1916 demonstrated that there would be 2 ½ days in every five weeks  when the necessary head of water would not be available from the tidal flows; meaning 25 days a year there would be no generation of electricity. It was also noted that over a running time of 46 days there were only 18 days that the high level reservoir could be filled and likewise only 25 days when the low level reservoir could be emptied. The maths at best did not add up and this was before any account was made for storms altering the levels by up to six feet or so, or tidal surges.

It was also pointed out that the power of the tides was uneven. In addition, no allowance had been made for the gravitational pull on such large areas of water and how this might affect the flow between the upper and lower basin. The desire to obtain constant power from the tidal waters just was not feasible.

The construction of the dams in the plan was compared to the construction of sea walls and embankments of Fen rivers which made no account of the massive hydrostatic pressures that a dam wall would have to resist, let alone the various quality of foundation available. As such it was like Belshazzar’s houses built on sand in the Bible and the writing on the wall for this proposed project spelled failure.

The project obtained further criticism in that it had not costed the cost of compensation to those affected by the change of use of the Wash and there were not even any costings for the electric cables that would attach the scheme to the electrical grid.

Finally, it was pointed out by Mr. H. Payn, the manager of Boston and District Electricity Supply Co that there was no account for the load factor of electrical generation, that is, that electricity is produced to fulfil demand. (It should be noted that this is a significant factor in  green electrical generation today actually adding to its cost.) Typically in Britain at the time very few generating plants operated at 50% of their potential and only achieved this by selling large quantities of electricity all night for chemical process work.

In conclusion Mr. Weaver’s tidal generation scheme for the Wash was a dead duck.

However, the ongoing consideration of putting a dam across the Wash arose again in 1937 when the eminent Dutch engineer Dr. Schoenfeld visited the Fens to review the flooding  and suggested in the Daily Telegraph that one solution might be to dam the Wash.

Dr. Schoenfeld made three proposals:

-          A great dam across the Wash from Boston to Hunstanton.

-          A barrage across the river Ouse at Kings Lynn to keep out tidal water.

-          A dam built across the whole southern half of the Wash.

In his articles he admitted that whilst his schemes were plausible he had “considerable doubt whether his proposals would be practicable or economic.”

Perhaps the most important aspect of his proposals was the discussion it opened up. However, from a flood control point of view it appears that they focused upon the e flood risk from the sea, but the increased flow of water from upstream was as much a risk as the tidal issues. But the issue as illustrated with the Ouse was a familiar one of lack of maintenance that would be an issue through to current times. In 1937 Sir Frederick Hiam of Cambridge pointed out: “……since the first Ouse Drainage Board was formed, scarcely any repairs have been done to the banks protecting the best fen land and although the owners and occupiers have had to pay big drainage taxes the money has been spent on poorer land. Today I should say the banks are not as safe as they were 20 years ago.” Sir Frederick continues to explain that it is the increased flow rate of water from upstream that is the most significant threat to the Fens.

It is interesting that the primary motivation behind these dam proposals was flood prevention compared to creation of agricultural land and electric generation.

Dr. Schoenfeld did meet the Agricultural Minister and questions were asked in Parliament, but for the moment the Wash dam project was damned.

December 1965 saw a re-emergence of interest in the Wash dam project. This time it was considered from many angles, but the primary driver was the increasing demand for water supply in the south east of England. This was perhaps the most open discussion of the Wash barrage as very early in the discussions experts and interested parties were gathered in a publicly recorded meeting at the Isle College in Wisbech as a “teach in”. At this time Binnie and Partners had created an initial short form report that was being reviewed by the Ministry of Housing and Local Government.

This time the Wash dam was being considered as a means for many developments. Although the primary driver in this instance was as a solution for water supply it was also recognised as an opportunity to grow new port facilities and a recreational centre. It was being looked at in a commercial manner as money spent vs. return in water and amenities. The report had been instigated by the Great Ouse River Board requesting that the Ministry of Housing and Local Government authorise an initial report after explaining projected future water shortages. At this time this was the most appropriate ministry, but soon after the Ministry of Land and Natural Resources  was formed alongside a Water Resources Board.

The Binnie and Partners report was a cheap, “quick and dirty” overview and it was acknowledged at the meeting that a full and complete feasibility study would cost £1.5million (£37million by 2026 value).

The Water Resources Board made it clear that any Wash dam would not be a quick process and a decision made in 1967 may not see anything until after 1975 or even 1985. In the meantime immediate action was required and this was seen in the region with the building of the Empingham Reservoir – in the 1970’s  renamed Rutland Water.

Mr. Oliver Dawson, director of Mitchell Construction Kinnear Modie Group Ltd, explained that a barrage from Gibraltar Point to Hunstanton would cover an area of about 200 square miles of which half would likely be reclaimed land and half reservoir. It was a lot smaller than the Dutch Zuider Zee where between 1933 and 1939 the Dutch had built four dams at a cost of £200 million and were now, in 1965 making further reclamation. However, despite the Wash being smaller it was technically more difficult due to larger tidal forces and storm surges. Mr. Dawson’s largest fear was that cost could put off action, whereby in the future we would only be too pleased to have paid the price as it would provide water for a quarter of Britain’s population by collecting water from a third of England rather than letting it flow into the sea.

Derek Page M.P. for Kings Lynn echoed this sentiment, “if we have any doubts about the need for this scheme let us think what the demand for water will be in 1980.”

Mr. H.L. Warburton of the Ministry of Land explained that the current estimated costs for the Wash as a reservoir showed it as a cost relating to capacity of  three times greater than a traditional inland dam and reservoir, and the cost of processing the water about twice that of current water treatment. He was also aware that other issues such as navigation, fish migration and effluent would have to be weighed up. One of the most significant aspects of the Wash dam is that it created farmland which was in contrast to a traditional dam that destroyed farmland as it was submerged.

Harold Clark, civil engineer for the Nene and Welland River Board explained that historically where there used to be one channel of water into the Wash keeping it scoured there were now three outfalls all experiencing silting due to insufficient scour. This dam would possibly involve a channelling of rivers into one channel.

Mr. H. Van Oosterman, engineer for the Great Ouse River Authority explained that there would have to be storage behind the dam for flood water for those occasions when excess water was flowing into the Wash, but could not be released into the sea due to high tides and storms. His view was that a dam from Gibraltar Point to Hunstanton would have to be 100 ft. high, whereas an optimum position may be further into the Wash from Binnington on the Lincolnshire side to Snettisham in Norfolk which could be at a lower 70ft.

Other engineers explained that effluent could be a problem damaging the potential water supply and the environment. Other environmental concerns were raised regarding shrimps, mussels and cockles that all would be destroyed. Similarly geese and waders would suffer.

Added to the mix of discussion by Mr. Derek Page the M.P. for Kings Lynn was the potential for North Sea gas to be piped in and used for industrial processes on 80 acres of reclaimed Wash land making raw materials such as nitrogen.

Amongst all the specialists of note was Fred White who had studied the concept of the Wash barrage for fifteen years or more. He had direct lived experience of the Wash having been brought up by his grandfather, marsh shepherd, Shep White as a child living just beneath the sea wall, and later becoming a highly successful farmer and grower and Marsh Reeve for the area collecting drainage rents and ensuring drains were maintained. This was an era that still respected local knowledge outside of academic circles. Fred White was highly regarded.

In 1968 Fred White published a book about the Wash and the potential to dam it entitles, “A Basin Full of Water”. In the book he examined the history of the Wash and considered a wide range of developments, ultimately proposing a plan of  action. Because of the plan described in his book Fred also described it in the preface as “a cauldron full of fire”, that answered many criticisms and difficulties of such a proposal.

In 1973, as a six year old I saw my first hovercraft landing workmen from what was known as the Wash barrage project. A few years later I attended a lecture on the project at Spalding Gentlemen’s Society. I remember little of this except for one point made by the speaker. He explained that fishermen would return from trips stating that the Wash barrage project was failing as some of the banks were collapsing, but they did not understand  that this was expected.

The first bank was built on the mud and sand flats which were dry at low water and covered by high tide. It was 200 yards long with a crest at 70 yards of 40 feet. This crest gave the impression of it being an island which I remember seeing. It was built to the maximum height needed of the poorest materials and the worst foundations so that its behaviour could be watched. Then a second bank was built under drowned conditions further into the Wash where foundation conditions were better, to understand how it could withstand tide and weather conditions.

By using silty sand and worst condition on the first bank it helped assess how and whether local material could be used successfully and if so where. Alongside the physical study of the swing of water entering the Wash and how the banks were effected were studies into the types of grasses that could be used to protect the banks. There were also studies into the likely effect on bird life and creatures in the sand, especially in the over winter feeding period. There was also a study of the distribution of shrimps, mussels and cockles to assess the effect of engineering works.

Away from the Wash the Hydraulic Research Organisation built a model of the Wash conditions at its research station in Wallingford to assess the effects of structures on sediment, tide movements, siltation and water levels. This information also helped assessment of the effects on fisheries and migratory fish.

By 1976 the National Water Council was recommending any plan to dam the Wash be shelved, possibly until the next century.

1989 saw a different use for the Wash being considered by NIREX to store nuclear waste. The following year saw a new generation of local politicians calling for a Wash dam feasibility study, apparently ignorant of what had happened before.

2022 saw Centre Port revitalise the Wash dam providing the world’s first tidal powered deep sea container terminal as well as tidal energy electric generation for the region and flood protection. That the local reaction is that “we’ve seen it all before” is understandable, but it has to be recognised that each generation that has looked at this development has brought something new. What the future holds for the Wash remains to be seen.