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Fig. 1. Illustrating correct and incorrect methods of locating trenches 



and dugouts. 



A. Correct trench construction. "Water escapes through the porous 

 jointed limestone. 



B. Incorrect trench construction. Water is held in trench by 

 impervious clays. 



C. Correct trench construction under same conditions as "B", when 

 it it is not feasible to sink the whole trench to the level of the porous 

 limestone as in "A".' A smaU drainage trench carries water down into 

 the porous limestone, permitting its escape. 



D. To the left, properly placed dugout. Drainage takes place read- 

 ily through the limestone, making the dugout relatively dry. To the 

 right, improperly placed dugout. Water fails to escape through the im- 

 pervious clay and the dugout is subject to very poor drainage or even 

 flooding. 



