32 



FISH FARMING: 



and the lower and upper parts of two other ponds; the 

 dotted lines D D D show the original bed of the brook ; E E 

 and E are controlling sluices ; and F F F F F is the underground 



FtGt-7. 



Fig. 7. Plan of a Pond on a Stream. 



drain, by means of which the water from the sluices is carried 

 off. In putting in this drain, be sure of ycur levels 1 , and see that 

 there is a good fall from E to F and from E E to F, and so on 

 through the series of ponds. At G G and G are horizontal box 

 screens; H, j, L, and M are adjustable sluices; K, K, K is a 

 surface surplus water channel, which also acts as a supply 

 channel when any of the ponds are being lowered, and thus 

 keeps a constant supply of water running through those ponds 

 not to be operated upon. 



By supposing K, K, K to be an existing stream, the drawing 

 becomes a plan of ponds formed off a stream. In the drawing 



Fig. 8. Plan of a Series of Ponds on a Stream in a Flat Country. 



I have shown the surplus water channel and the surplus water 

 drain on the same bank, but this need not be so; indeed, 

 where circumstances are favourable, they are better kept on 

 opposite banks. 



