20I0 The Cornell Reading Courses 



measure, it is determined by the topography of the land and the character 

 of the water supply. Any fairly level acre of land situated slightly below 

 a flowing spring or the water level in a creek, and at the same time a few 

 feet above contiguous ground, constitutes an ideal location. From the 

 water source to the lowest point on the farm there should be a total drop 

 of at least seven feet; this will allow a gravity flow from the water source 

 to the pond, and also from the bottom of the pond to some other point 

 for draining. 



. While the ideally situated pond is one that can be completely drained 

 by merely pulling a plug or by means of some other simple device, suc- 

 cessful fishponds have been made in low-lying swamp or marsh land 

 incapable of drainage and worthless from an agricultural standpoint. 

 The soil removed in excavating such a pond often possesses high value 

 as a fertilizer and may be used to advantage on upland fields. At any 

 rate a pond is much more profitable than a mosquito-infested waste. 

 The principal thing to be kept in mind in making a pond in such a location 

 is the necessity for plenty of water during the summer months. 



WATER SUPPLY 



The water supply for a fishpond may be obtained in a number of ways : 

 namely, direct from a spring or stream by gravity flow or by the use 

 of a hydraulic ram; from an artesian well; from a well of the ordinary 

 type by the use of a windmill; and finally by conserving the rainfall and 

 the ordinary land drainage. 



Spring water and artesian well water 



Flowing springs or wells are the best sources of water supply for the 

 farm fishpond if the water from them is of the right quality, because 

 this water is most easily controlled, is usually permanently clear, and 

 is warmer in winter than creek water, thus making part of the pond free 

 from ice. Much spring water is free from pollution and dangerous min- 

 erals and gases, and may be led directly into the pond. However, water 

 may be tested by placing a few fishes in it; if they remain alive for a 

 week or so, the water may be considered suitable. 



On the other hand, water may contain a number of undesirable sub- 

 stances in solution. Such minerals as arsenic, salt, and iron, if present 

 in considerable quantities, are injurious to fishes, and water containing 

 these minerals should not be used in a fishpond. Hard water is unde- 

 sirable not because of the presence of lime carbonate but because it may 

 contain obnoxious gases: for example, hydrogen sulfide, marsh gas, and 

 carbon dioxide — all of which are injurious. Hydrogen sulfide imparts 

 an undesirable flavor to fish flesh ; marsh gas and carbon dioxide, if present 



