Modern Drainage Problems 203 



5 miles out to sea. His contention was that the siking of the river was due 

 to material in suspension and that this should be excluded. A further 

 report was subsequently prepared by Sir Alexander Gibb, but the fmancial 

 burden was impossible for the Ouse Drainage Board to carry. 



By 1930, the original short training walls had seriously deteriorated. 

 But the Ouse Drainage Board felt that it could not finance any improve- 

 ment, which was, therefore, undertaken by the Lynn Conservancy Board 

 with Government assistance. The principle adopted was to protect the toe 

 of the existing walls by means of brushwood mattresses and to heighten the 

 tops by a combination of brushwood and stone. This particularly suitable 

 method of repair was put forward by a firm of contractors of Dutch origin, 

 who were operating in this country. Subsequently, the firm called in two 

 eminent Dutch engineers, and the result was the so-called "Dutch 

 Scheme", wliich was considered by the Labour Government in 193 1. By 

 this time, conditions in the estuary had become so bad that it was estimated 

 that it would cost five and a half million pounds to put it right. 



The "Dutch Scheme" provided, as before, for the widening of the 

 river from King's Lymi to Denver and Welmore Lake Sluice. It also 

 advocated the cutting through of Magdalen Bend and the widening of 

 the Hundred Foot River. Because the upper section of the tidal river had 

 probably been silted up by material coming in from the Wash, it was 

 proposed to construct a set of sluices across the Hundred Foot River in 

 the neighbourhood of Welmore Lake Sluice. From here down to the sea 

 the toe of the banks was to be protected by mattresses, and their slopes 

 pitched with concrete blocks. To take the river out to deep water, training 

 walls over 5 miles long were suggested. The lower portion was to be made 

 with mattress work, and the upper portion was to consist of caissons of 

 concrete blocks. The height was to be brought up to at least neap-tide 

 level, and, in order to regulate the depth of channel, a series of groynes 

 was to be constructed inside the new walls. Although the Government 

 offered a 90 per cent grant, it was again felt that the Catchment Board 

 which had just come into existence, in 1930, could not face the financial 

 burden. 



But, at this time, the Catchment Board had to face the reconstruction of 

 training walls for a length of i mile on the eastern side. This had to be done 

 under difficult financial conditions. Work was undertaken in 1932 and 

 cost the Board ^85,000. It was felt advisable to reconstruct a new wall 

 slighdy behind the old wall, and to carry it up to a somewhat higher level.^ 



During the dry summers of 1934-35, silt travelled^ steadily up-river 



' Both the east and the west training walls were extended a short distance in 1937. 

 * See p. 189 above. 



