Part I.] Fish Ponds. 17 



The dam being 12 feet in height this would give a width of 

 24 feet. On the land side the slope is also 2 feet to each foot in 

 height. This would make a width of 24 feet. The dam is 8 

 feet wide on top, therefore 24 plus 24 plus 8, or 56 feet, should 

 be the width of the base at the middle or widest part of the 

 foundation of the dam. 



By reference to the diagram and map (figs. 3 and 4) it 

 will be seen that the earthworks of the dam gradually nar- 

 row up to a width not much greater than the eight-foot 

 roadway at the ends. With the foundation well laid, the 

 matter of the building of the embankment consists very largely 

 of hauling and scraping in the dirt. To make headway, good 

 teams and large scrapers should be used; and to insure solidity 

 in every part of the structure as it gradually grows in its 

 proportions of width and height, the dirt should, as we have 

 said before, be spread evenly, and the surface of the embank- 

 ment should be kept as nearly level as possible while it is 

 being built. If high and low places appear on the surface, or 

 if one side is built up while the other remains low, the tramp- 

 ing and packing of the dirt will not be even and the finished 

 dam will, while settling, be liable to show irregularly high and 

 low places on the surface. I make special mention of this be- 

 cause I have noticed that dams settling irregularly are more 

 liable to leak than those that settle evenly. 



Should a few rains fall on this structure while being built 

 it would aid very materially in packing the ground. No dif- 

 ference, however, how much care is taken, it will take years 

 for the embankment to settle thoroughly, but careful building 

 may save trouble and expense by guaranteeing even and regu- 

 lar settling, especially during the dangerous period of the 

 first two or three years after the dam has been completed. 



The Overflow or Spillway. 



Another all-important thing about the construction of a 

 pond is to have a place where superfluous storm and flood 

 waters can escape without injuring the dam. It is very diffi- 

 cult to give directions for the construction of spillways and 

 overflows that will be applicable to all places, as the conditions 

 in no two localities would be exactly the same. However, by 

 observation and experience I have learned some general facts 

 concerning overflows and spillways that may be helpful to 

 those who are contemplating the building of ponds in places 

 where it will be necessary to build such structures. Some 

 knowledge of the amount of water that is liable to flow into 

 the pond during and after heavy rains and snows would be 

 necessary before the proper allowance of space could be made 

 for its escape. No water should be allowed to run over the 

 earthworks of the dam, as it would soon wash and wear away 

 the embankment. 



The overflow or spillway should be constructed at or near the 



