FISH PONDS ON FARMS. 9 
usually be materially increased by sinking 2-foot lengths of terra- 
eotta pipe over the bubble and removing the incased earth. Several 
such pipes in a promising area will often result in an astonishing in- 
crease in flow. Where the cost is not prohibitive, however, the better 
course will be to excavate the site and wall it in with rock and 
concrete. 
In profusely watered sections—notably, in the States bordering the 
Great Lakes—there are many tracts of marshy characteristics. some 
of them hundreds of acres in extent, promiscuously interlaced with 
tiny rivulets which combine to form streams of considerable size. 
Seemingly inexhaustible quantities of water lie close to the surface in 
many such places, and by driving pipes only a few feet into the 
ground flowing wells are obtained. 
Where the volume of water is a matter of concern the overflow 
level of spring reservoirs, sunken tiling or driven pipes should be 
kept as low as possible, consistent with the object in view, as the flow 
will naturally decrease with the elevation of the head against which 
it works. 
A brood pond contiguous to a spring reservoir may be fed through 
a spillway directly into the stock pond. Where a reservoir is im- 
practicable, at least partial correction of any abnormal condition of 
the water may be brought about by conducting it to the pond through 
open ditches or raceways of wood or concrete, the choice of material 
being determined by adaptability of the soil and the comparative 
expenditure involved. 
The chief objection to creek or river water as a supply for fish 
ponds is the great quantity of mud and débris carried during fresh- 
ets, and the excessive cost of effective measures to prevent its intro- 
duction into the ponds. Streams subject to extremely high-water 
periods are totally impracticable as a source of supply, while those of 
lesser floods can be utilized only after a considerable initial expendi- 
ture, and much vigilance will be entailed in their use, as large and 
continuous deposits of mud in breeding ponds will ruin any eggs 
present, and invariably kill recently hatched fry. Furthermore, pro- 
tracted roily water will retard and sometimes prevent growth of 
the aquatic vegetation so essential to pond fish-cultural operations. 
It is also imperative that undesirable and predaceous fishes be rigor- 
ously excluded from the ponds, and it will be impossible to accom- 
plish this if the water supply is beyond control during certain 
periods. 
From the foregoing it can readily be seen that if a stream is sub- 
ject to appreciable changes, as a result of stcrms or drainage from 
local watersheds, it will be unwise to establish a pond therein by the 
construction of dams, as is often contemplated. It will be entirely 
feasible, however, to conduct water from such a stream to ponds ad- 
