THE ANGLER AND HUNTSMAN 95 



water is a spring or lake, and if from the latter the water 

 should be taken from below the surface in order to afford 

 a more even temperature Alkali water and water from 

 forests showing discoloration and traces of tannin are not 

 suitable. 



"The flow of water requisite in a fishpond will vary 

 with the nature of the soil, the species propagated, and the 

 water temperature. Soils containing a good deal of sand 

 will lose water through seepage, making it essential to pro- 

 vide for a larger inflow in order to maintain the pond level. 



" Under ordinary conditions the rainbow trout, because 

 of its ability to withstand a higher temperature and.a more 

 sluggish water circulation, will yield better results in ponds 

 than the brook trout. The brook trout thrives best in a 

 swift current fed by cold springs, and attains its maximum 

 excellence in streams. However, an exception is found in 

 certain lakes in Colorado, where the introduced brook 

 trout attains its largest size. Assuming that it is desired 

 to carry 1,000 yearling trout in a 1-acre pond fed from a 

 spring or brook, a flow of from 150 to 200 gallons per min- 

 ute will be sufficient, provided the temperature ^of the wa- 

 ter at the point where it enters the pond does not exceed 

 60 degrees F. during the summer months. Trout confin- 

 ed in small streams with a strong flow will withstand a 

 temperature of 70 degrees without harm. 



"If the water supply to the proposed pond is from a 

 spring, it should first flow into a reservoir and thence 

 through an open raceway into the pond. This will permit 

 it to throw off injurious gases and acquire the normal 

 amount of oxygen. Logs placed across this open conduit 

 at frequent intervals will provide the riffles necessary for 

 varying the flow, thus approaching natural conditions. The 

 water is allowed to pass over them, although no harm will 

 result if it occasionally flows underneath. Rocks also may 

 be used to accomplish the desired end. 



If a stream is to be the source of supply, a screen, so 



