ESTABLISHING THE HATCHERY 



line and can be tipped to the de- 

 sired level to drain the pond. 



Another outlet is merely a cement 

 block laid around the outlet pipe, 

 attached to which is one of a num- 

 ber of gates ( fig. 7 ) . The most com- 

 monly used gate is the usual irriga- 

 tion gate, the cost of which wnll 

 vary according to size and type 

 used. A homemade gate can be 

 made by bolting a channel iron to 

 the block on either side of the open- 

 ing and inserting a piece of boiler 

 plate that fits over the opening and 

 has a handle welded on it (fig. 8). 

 It can be made by a blacksmith. 



Eesearch workere at Alabama 

 Polytechnic Institute, Auburn, 

 Ala., have designed an inexpensive 

 gate which is attached to the bell of 

 a piece of soil pipe. They recom- 



mend an adaptation which is at- 

 tached to a 30° ell so that the gate 

 can be opened by pulling a wire on 

 shore. This arrangement eliminates 

 the need for a platform to the out- 

 let, which must be located in the 

 pond beyond the toe of the levee and 

 at the low^est point in the bottom. 

 If the pond is to be drained fre- 

 quently, however, one of the stand- 

 ard outlets for hatchery ponds 

 should be used. 



Hatchery ponds should be 

 equipped with an outlet to permit 

 ready drainage and removal of the 

 fish that have been propagated. 

 There are two general types of out- 

 lets which may be adapted to con- 

 ditions. One type has the outlet 

 and water-control structure inside 

 the pond and the catch basin for 



Ovirflow slandpip* 

 if dasired •— ^ 



Figure 7. — Cement-block pond outlet. 



16 



