The Draining of the Fens 193 



the Grand Sluice and the Black Sluice; on the Nene, the North Level 

 Sluice; on the Ouse, the St Germans Sluice and Denver Sluice.' Upon 

 Denver Sluice depended the safety of the South Level. Its importance 

 wiU be apparent from E. G. Crocker's summary in 1913 : "The level of 

 the top of the banks is from 12 to 13 feet above o.d. wrhilst an ordinary 

 spring tide rises to 14 feet above o.d. at the sluice, the highest recorded 

 tide being 17-51 feet above o.d., so that should anything occur to prevent 

 these gates closing in a spring tide, practically the whole of the Fens of the 

 South Level would be flooded." There was a further complication. 

 Immediately below Denver Sluice, the waters of the Hundred Foot River 

 (carrying the upland Ouse from Earith) fell direcdy into the estuary 

 (see Fig. 53). Consequently, when there was a great volume of upland 

 water passing down the Hundred Foot River, the level of water in the 

 Ouse outfall (on the seaward side of the sluices) never fell low enough for 

 the sluicegates to be opened to provide an adequate run-off for the waters 

 of the South Level. These waters could only accumulate within the 

 straining banks of their dykes and drains. A crisis was, therefore, always 

 liable to be produced by the combination of (i) adverse wind conditions, 

 (2) a high spring tide and (3) heavy land floods. 



Bibliographical Note 

 The older works of most general interest are : 



(i) S. Wells, The History of the Bedford Level, 2 vols. (1830). 



(2) S. B.J. Skertchly, The Geology of the Fenlatid (1877). 



(3) S. H. Miller and S. B.J. Skertchly, The Fenkiid Past and Present (1878). 



(4) S. Smiles, Lives of the Engineers (ist ed. 1861), has much interesting material. 



(5) Sir William Dugdale's History of Imbanking and Drayning (1662). This is, of 



course, the classic account of the seventeenth-century draining. 



The following more recent accounts give detailed sources for the facts 

 recorded in tliis chapter: 



(6) H. C. Darby, "Windmill Drainage in the Bedford Level", Official Circular 



No. 125, Brit. Waterworks Assoc. (1935); also The Engineer, clx, 75 (1935). 



(7) H. C. Darby, "The Draining of the Fens a.d. 1600-1800" in An Historical 



Geography of England before A.D. 1880 (1936). 



(8) H. C. Darby and P. M. Ramsden, "The Middle Level of die Fens and its 



Reclamation", Victoria County History of Huntingdon, iii, 249 (1936). 



' In addition to the sluices at the outfalls of the Old Bedford River and Well Creek 

 (see Fig. 52). 



DBA 



13 



