Modern Drainage Problems 195 



The increase in lift, owing to the lowering surface, stands out. By 1913, 

 this had become 15 ft. 4 in. — or an increase of nearly 6 ft. over a period of 

 80 years. Some of the older engines still exist to-day, standing near the 

 modern pumps. There is one at Upware; another (installed about 1840) 

 stands alone in the Glassmore district of the Middle Level. 



Crude oil or Diesel engines were introduced for pumping purposes 

 about the year 191 3. The weight per unit horse-power is much less than 

 for steam — a great advantage in an area of soft earth where foundations 

 a] e expensive. There are, however, other advantages of special moment. 

 Most of the pumping stations are, of necessity, near river banks and hence 

 away from hard roads. The cartage of coal, particularly if extra supplies 

 are required during winter, is expensive. But the great loss with steam 

 comes in starting-up and stand-by costs. Pumping for drainage is mainly 

 seasonal, and even then spasmodic. With heavy rainfalls, the pumps must 

 be under way by tlie time the water has percolated into the drains. When 

 this water has been discharged from drain to river, the engine must ease 

 dovrai, or even stop, for some hours until the drains fill up again. With a 

 steam-driven plant, steam must first be raised in the boilers in anticipation 

 of pumping; then, when the pump has shut dovra, the fires must be either 

 banked or drawn until the plant is required again. This involves unneces- 

 sary fuel consumption and may at times require the services of an extra 

 driver. On the other hand, the use of oil-driven plants does mean that, 

 in the event of hostihties, provision will have to be made for a supply of 

 fuel-oil. It is possible, therefore, that the steam-engine could be kept, with 

 advantage, as a stand-by, and this is the practice adopted by some of the 

 best managed Internal Boards. 



The pumps installed since 1919 show an increase in horse-power and 

 capacity, not entirely accounted for by the necessary increase in hft. The 

 average lift in 1913 was between 7 and 15 ft. Higher lifts are more generally 

 met with to-day, rising to 21 ft. for the plants in the S waff ham, Bottisham, 

 Littleport, and Downliam districts, and even up to 26 ft. in the North Side 

 district, Wisbech. This increased lift is only partly accounted for by the 

 lowering surface ; it is also due to the modern practice of deepening and 

 enlarging the drains so that the water can be kept lower. This provides greater 

 storage capacity, and at the same time gives better drainage. Some of 

 these leading drains are of considerable size, so that the pumps need not 

 run so frequendy. 



It is difficult to generalise about the size of pumps used. About 1926, 

 the size rose to 42 in. pumps with a capacity of 150 tons per minute; 

 requiring about 250 horse-power; but more recently the size of pumps 

 installed has fallen to 24 in. with a capacity of 70 tons per minute. Tliis is a 



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