192 



The Draining of the Fens 



River Ouse to keep a defined channel among the shifting shoals that, 

 accumulating in the estuary, interfered with the effective discharge of 



Yards 



250 



The Outer Line represents 



High Water Mark of Ordinary Tides 



Salter's Lode Sluice 

 Old Bedford Sluice 



Fig. 52. 

 The Sluices near Denver. 



w^ater from the two Levels.' But the nineteenth century brought no 

 solution to this problem. 



Important features of the outfaUs were the sluices necessary to prevent 

 the tidal waters from passing up the rivers. On the Witham, were 



' See p. 201 below. 



