Drainage of Brue Valley

The following is dedicated to the memory of Mr J.M.Hitchen M.I.C.E. M.I.M.E Deputy Chief Engineer to the Somerset River Catchment Board from January 1941 to 31st December 1947.

In 1941 a Top Secret Scheme was discussed, the purpose of which was to drain the Brue Valley in order to provide 9,000,000 million gallons of fresh water per day for a new munitions factory. Many secret meetings took place and eventually work commenced on a vast scale to transform the Somerset Levels, resulting in a scene that altered the Somerset landscape forever.

A chance meeting between one of our researchers and the daughter of the man, who was appointed to be responsible for the design, has resulted in this story being told.

Mr J.M.Hitchen, was the man who dedicated himself to the project. A task that would have been difficult under present day working conditions, but in wartime it was an enormous undertaking and because of its importance, a very strict timetable had to be kept.

We are greatly indebted to Mr Hitchen’s daughter Mrs E.M.Lawson for her generosity in donating, to us, the material her family has safely stored and cherished over many years. Press cuttings, photographs and copies of publications were kept. We therefore greatly appreciate the help Mrs Lawson gave to us so that we could record this important time in the history of the Somerset Levels.

A STORY THEY COULD NOT TELL

For hundreds of years the land close to Highbridge has been flooded during winter months, the land remained fallow instead of being used to produce food. However, during the 1940’s something was done about this failure when 100,000 acres of land was saved for food production. The remarkable feat of engineering was shrouded by wartime security, thus little was known until the end of hostilities.

The feat involved the drainage of 55,000 acres of land at a cost of £600,000; it lay in the hollow between the Mendips and the Quantocks. It is bisected by the low ridge of the Polden Hills, into  areas of grass and moorland; two rivers run through it, the Brue and the Parrett, both flowing into the Bristol Channel.

The estuary of the River Parrett boasts the second highest tidal variation in the world (some 35ft) and the water is full of silt. Over a period of centuries the silt has cut off the lowland and the moors of Somerset from the sea by depositing a belt of silt at the estuary some 8ft higher than the moorland itself.

It was on these moors that Alfred outwitted the Danes (and burnt the cakes) and where the ill-fated Monmouth fought his battle, for centuries floods were a regular occurrence. The Abbots of Glastonbury owned Brent Marsh, as it was called in the Middle Ages, and the floods once swept into Glastonbury itself. Between the Mendips and the Polden Hills is a “dish-like” area where 20,000 acres were liable to flood regularly each winter and, after heavy rainfall when the Brue filled up, the side drains could not discharge, the land was then flooded until the river level dropped. Further, water levels were continually upset by peat digging in the Glastonbury area and this was an area of the moors used mostly by small dairy farmers for grazing. But because the tide and consequent flooding came so swiftly, cattle feeding in dry pastures in the morning could be in three feet of water by evening. Plans to effect a permanent cure to all this were made long before the war by the Somerset River Catchments Board, but the agricultural depression came along and plans had to be shelved.

It transpired that early in World War Two, the then Ministry of Works called in the Somerset River Catchments Board and gave their Chief Engineer Mr. E.L. Kelting a severe shock by announcing that a munitions factory was to be built in the area. The factory would manufacture R.D.X. * a new explosive and would require 9,000,000 gallons of fresh water per day.

*  R.D.X. was the explosive used in the bombs dropped on the Ruhr Valley dams by the “Dam Busters” in their raids.

To supply such a large quantity of water in winter would have been difficult at any time, but all -the-year-round, was asking rather a lot; farming in the Brue Valley would have been ruined. The wide ditches, (rhines) which constitute the field boundaries, would have dried up and much of the whole area would have reverted to commonland. There would have been no water to promote plant growth and nothing for cattle to drink. In 1941 the Farmers Weekly carried an article stating that the largest drainage undertaking in Britain since the Dutchman cut the rivers of the Fenland in the 17th century, was about to be engineered. The scheme would involve the drainage of some 45,000 acres, of this 4,000 acres flooded annually.

Secret meetings took place and eventually the Ministry of Works reduced its demands from 9,000,000 to 3,500,000 gallons per day, a more feasible proposition. This was a golden opportunity to drain the moors, there would not be a shortage of money or would there be difficulty in getting labour or implements. All previously pigeonholed plans on draining the moors were dusted off and re-examined. One such plan had proposed the cutting of a new river to give extra outlet from the Brue Valley to the Parrett estuary. If this New River were to be utilised as a reservoir, holding its capacity in summer and discharging the surplus through sluices to the river during the winter months, the factory would obtain all the water it required. This was the plan adopted and with a large cheque from the Government the Somerset River Catchments Board and its Chief Engineer were able to start. Due to incidental and wartime needs of the munitions factory, the farmers of the moors would soon have an efficient drainage and flood prevention scheme. The levels had needed such a scheme since Neolithic peoples had lived on piles in the lake villages of Meare; three queens in a barge had rowed the dying King Arthur to the Isle of Avalon (Glastonbury) the mythical paradise of the Celts.

The work had to be done in a hurry; in fact it was to be completed in three years from January 1940. Often draglines, scrapers and bulldozers were at work in pastures before the farmers had any idea of what was going on. Matters were not improved by the complete secrecy that had to be maintained as to the main purpose of the work. The military looked enviously at the fleet of earth-moving equipment and made unsuccessful attempts to requisition some of it.The New River would be 5 miles long and 200ft wide, and would run in practically a dead straight line, entering the Parrett estuary southwest of Highbridge. It was intended that the river would be 24 ft deep, but at this depth a layer of soft blue clay was found. Tractors, scrapers and once a 30ton dragline sank in the stuff. A comprise depth of 16ft was agreed with the sides sloping at one-in-four. Because it was not possible to go deeper, the idea of running water from drainage channels into the river by gravity had to be abandoned.  At Gold Corner, which is at the inward end of the river, and at the division between the lower land of the moors and the higher levels towards the estuary, a pumping station was built. When water collected in the main cuts leading to the pumps is below the level of the Huntspill River, (in June 1947 it was about 8ft below the river level) and it can be pumped. When the higher winter level is reached, it is possible for it to flow in by gravity.

The pumping station was reported to be the most imposing of all those constructed in Britain during the wartime, houses four screw-type pumps driven by diesel engines. They have a combined capacity of 620 cubic feet per second or about 1,000 tons a minute. When full, the Huntspill River contains some 232,000,000 gallons, after which any surplus water is allowed to pass into the River Parrett through the outfall sluice.

A feature of the building was the window area, giving excellent lighting inside, a very desirable requirement where costly machinery needs close attention during its operation. Glazed lights in the flat reinforced concrete roof supplement this and a section of the roof comprises a cooling water tank for the engines. German and Italian Prisoners of War were the main labour force, outnumbering the English workers.

New Bridges

Six new bridges were necessary, five to carry the main roads, the sixth to take the Bristol to Exeter main line railway. Because of the nature of the subsoil, bridge building was not easy, all are carried on piles and in most cases these are over 60ft long, the longest being 84ft long.

At the outlet into the estuary, tidal sluices were necessary so that the river could discharge on low tides and be held back during high tides. Once, during the construction, disaster nearly struck; to keep the water out whilst the sluices were built, a U-shaped bank was built out into the estuary as protection.  One dark November night a gale whipped up the high tide to nearly two feet above the predicted level and the foreman, Mr. Dixon on his nightly rounds found to his consternation that the water was flowing over the top for a stretch of approximately ten feet. He grabbed a spade and set to work building up the bank, his spade broke, but he groped about in the dark and found another, no lights were possible due to blackout restrictions. After working for an hour and a half the tide started to turn and he had won, he had saved the bank, had it given then, all the work would have been ruined and they would have been set back weeks.

When the sluices were opened a small hole was cut in the protecting bank and the water very quickly washed away the remainder of the wall. Unfortunately the bottom of the river between sluice and estuary proved none too sound and began to erode. Luckily, it was spotted quickly and Mr. Hitchen commandeered all the lorries he could and sent them chasing around Somerset collecting concrete roadblocks. About 1,500 of these, together with concrete static water tanks and a steel barge were hastily sunk in the outlet from the sluices and these now provide a firm bottom.

The spoil removed from ‘cutting’ the river was levelled on the bank and after due “weathering” and shrewd treatment with artificials was re-seeded and today these banks provide first class grazing. There is no question that much of the land in the Brue Valley has been vastly improved by this modern and comprehensive drainage scheme. The fact that 1,000 tons of water that once flooded the land of the valley and is now pumped into the Huntspill River every minute is testimony to that. Also the water table in the Rhines can now be controlled and a complete ”drying up” can be avoided. It was considered at that time, the internal channels and ditches were still not good enough to get the water to the main drains leading to the pumps. Apparently there was not a legal limit in England, to which peat diggers may work and this had a considerable effect on the water in the internal ditches. None the less, 40,000 acres of Somerset farmland had benefited from the country’s wartime needs in the matter of explosives, the State paying the greater proportion of the cost.

Two of the new bridges featured foundation work of special interest, they were completed in 1942, the one being at Dunball; the other at Huntspill. They were constructed to allow the new river channels to pass under the main railway lines. The building of railway bridges in the area presented many problems and, at that time, it was a case of humouring nature. Especially in alternately coaxing and commanding the co-operation of that highly persistent and intractable element, water.

The new channel at Dunball was a diversion of the old King Sedgemoor Drain, which was constructed in 1795 to take the waters of the River Cary, but the Huntspill was an entirely new river. The construction of which had already involved the excavation of 5 million cubic yards.

Dunball Bridge was constructed entirely from reinforced concrete, having two 20ft spans. There already existed a railway bridge and station platform, these prevented a track diversion. A very fine quicksand of considerable depth was encountered some five feet above the New River bed; this caused serious difficulty in the excavation work. This problem was eventually overcome by the use of a de-watering system of “well-points”. A special diesel pump capable of extracting 60,000 gallons per hour was used to deal with this volume of water in the “well-points”. When a considerable volume of water had been extracted, the sand became sufficiently firm to be easily removed by ordinary excavation methods.  The Huntspill Bridge has five spans-one 50ft main steel span and two 16ft spans of reinforced concrete. It is carried on reinforced concrete piles, driven through the soft clay and peat beds to rock lying at a depth of 80 ft below railway track level; the driving of the 65ft piles, each weighing about 7.5tons, was facilitated by making a diversion of the tracks for a distance of five hundred yards, during the construction of the bridge.

Although a major engineering feat was carried out some 60 years ago, the Somerset Levels are still affected by floods. Whether this is caused by‘global warming’ or by some other environmental reason has yet to agreed but the inhabitants of the area suffer every time there is heavy and prolonged spells of rain. Perhaps another drainage scheme is the answer, who knows?

The Huntspill River with the Gold Corner Pumping Station, the new sluices into the River Parrett to control the tidal flow and the sluices on the Brue River all help to reduce the risk of flooding on the scale experienced pre-1940’s. The drainage schemes put in hand in the 1940’s help prevent much of this flooding, but a lot still needs to be done. However, they were able to say that work started by the Abbot of Glastonbury seven hundred years ago has moved a little more towards completion.

(Permission to use the foregoing material was granted by Mrs E Lawson)

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