138 



MOSQUITO ERADICATION 



Streams which, during a period of drought, partly dry up, 

 leaving depressions or "pot-holes" along their courses, should be 

 treated similarly to ditches which give rise to similar troubles. 



FILLING 



Collections of water that cannot economically be drained 

 should be filled when practicable. Wet areas that are most 

 expensive to control should be eliminated first. Shallow water 

 in places that are too low to be drained may be concentrated 

 by filling, so that the remaining water is easier and cheaper to 

 control. 



{Photo by E. H. Magoon, C. E.) 

 Fig. 99.— Making a fill. 



Frequently, it is possible to procure that city trash be dumped 

 at the place it is desired to fill. This course may not be practi- 

 cable, however, where the haul is too far or where the place is in 

 a thickly-inhabited section. In all cases, the trash must be 

 levelled off so as to prevent the formation of pools, and should be 

 covered with 6 inches or more of earth in order to prevent odors, 

 especially in summer. Under no circumstance should potential 

 water-containers, such as old cans, bottles, etc., be left exposed. 



Porous materials, such as cinders, are very good for filling. 

 In the vicinity of lumber-mills, waste, saw-dust and shavings 

 are available in quantity, and, when used for filling, should extend 

 several inches above the surface of the ground. 



Areas kept wet by seepage water can seldom be satisfactorily 

 treated by making a shallow fill of earth. 



