FISH PONDS ON FARMS. 11 
remainder of the year. In the absence of this reserve many such 
ponds become practically dry during periods of drought or freeze to 
the bottom in the winter months. Where ponds are subjected to 
such conditions fish cultural operations are impracticable. 
Ponds dependent entirely upon precipitation and surface drainage 
for their water supply must necessarily be located at a low elevation, 
in order that the surface drainage from surrounding lands may be 
taken advantage of. Land depressions, ravines protected from 
floods, or swamp lands, are desirable sites for such ponds. 
Catfishes only can be recommended for the best of “sky ponds,” 
strictly speaking, and the results even with them will be very 
uncertain. 
DESIRABLE SITES FOR THE LOCATION OF PONDS. 
If a gravity flow of water is contemplated, the fish pond must, of 
course, be located below the level of the source of supply. Porous 
soils are to be avoided, if possible, not only because of the large 
volume of water required to replace loss from seepage but because 
they are usually sterile. Swamp lands, old water courses, and 
catch basins of years’ standing are the best and most productive soils, 
as they possess the required fertility and contain seeds and spores 
for the early development of profuse vegetation and animalcula. 
Ponds located in such soil will maintain their water levels with a 
minimum inflow. 
Satisfaction may be had from ponds less favorably located, how- 
ever, if good sense is employed in their preparation and maintenance. 
Aside from the ideal lands of alluvial deposits, clay loams are a first 
choice, being most nearly impervious to water and quickly responsive 
to efforts made to establish their fertility. Sandy loam, being the 
most prevalent, is probably the most general soil in use for pond 
construction. While some difliculty may at first be experienced in 
making it retain water, this is overcome in time by the accumulation 
of decayed vegetation. Its fertility is good and, in general, it pro- 
duces a sufficient supply of natural food. Even clear sand and gravel 
mixtures may be made to hold water and brought to fair productivity 
by increased expenditures in construction, and by the application of 
fertilizers in a manner to be explained later. 
It is very desirable, and also essential for a marked degree of suc- 
cess, that ponds be so located and constructed that they may be en- 
tirely emptied of water at certain seasons. To this end there should 
be accessible a natural dry run or water course lower than the bottom 
of the proposed pond, to which drain pipes may be conducted. 
Ponds are drained for the purpose of assorting fish, removing ob- 
jectionable species, reducing the stock, killing out excessive vegeta- 
tion, etc. Complete drainage can not be effected, of course, unless 
