[43] 



rOND CULTURE. 



509 



should be furnished to the ^Yater, somewhere along the bank, usually 

 near the point of the dike. This is likewise done by ditches which re- 

 ceive and carry away all the superfluous water from the j^ond and the 

 surrounding: cultivated land. These ditches, of which a large pond should 

 have several, must at their starting point near the bank be closed with 

 grates, so that no fish can escape through them. Such ditches also be- 

 come necessary, where, after violent rain storms, or by the melting of 

 the snow in spring, there iS danger of inundations. To receive and 

 carry away the water from such inundations, ditches should likewise be 

 constructed in suitable places. 



7. ARRANGEMENTS FOR LETTING THE WATER IN AND OUT. 

 A. — Weirs witu locks (sluices). 



The feeding ditch receives its water either, a, from a river or brook ; 

 b, from one or several springs ; c, from rain or snow water (as in sky 

 ponds) ; d, from other ponds. 



a. A pond may be fed by a river or brook, either by ha^ing a portion 

 of its Avaters led into it through channels, or by causing the entire 

 stream to pass through the pond. In both cases it will be necessary to 

 put a weir, with locks, at the place where the water enters, so that the 

 supply of water may be properly regulated. In the first case, the water 

 pursues its natural course in the bed of the river; and, in the second 

 case, i. e., where the weir is placed in the stream itself, the water has to 

 be led in ditches round the pond to rejoin its original stream below 

 the same. Iv both cases a narrow grate should be put at the place 

 where the water enters the pond, so as to keep out intruders, especially 

 fish of prey. Such weirs are constructed in the following manner: 



Fi^.n. 



Along the banks of the river, or at the opening of the dam (when 

 the brook or river passes through the pond), strong wooden posts, a b 



