RESERVOIRS AND PONDS. 99 



gradual, not abrupt, for the reason that if the walls 

 are nearly perpendicular wind waves will destroy them, 

 hence the advantage of making the walls very sloping 

 from the inside. The outer walls may be made more 

 perpendicular, because there is no influence from the 

 outside to injure them. 



Having built the walls by using the earth from the 

 inside of the reservoir, and with everything ready for 

 puddling the earth to hold water, the first thing in 

 order is to plow all of the land over the whole bottom 

 surface of the reservoir four or five inches deep, then 

 with a harrow or drag, or other suitable implement, 

 reduce the earth to a very fine pulverization, and after 

 this shall have been thoroughly done the next thing is 

 to puddle. Turn the water into the reservoir and be- 

 gin to puddle at one edge, puddling carefully along 

 this edge until the earth shall have been reduced to 

 mortar, and continue to work toward the other side 

 until the entire bottom of the pond is completed as far 

 up the embankment as can be worked to good advan- 

 tage. It may often happen that puddling is out of 

 the question owing to the porous condition of the bot- 

 tom. If the soil is sandy haul into the basin several 

 loads of any kind of clay obtainable and mix this 

 thoroughly with the earth. Fresh manure, or even 

 sawdust, may often be employed to just as good advan- 

 tage. Very often it is only necessary to run muddy 

 water into it and allow the sediment to find its way 

 into the loose sand. Of course the more clay that is 

 carried in the muddy water the more effe(5lual will 

 be the puddling. This method has proven success- 

 ful in a very leaky lake which was excavated in an 



