188 THE farmers' handbook. 



TANK SINKING. 



Owing to the settlement of returned soldiers on the land, and also the 

 lessons of the 1918-19 drought, more work may be done in the future in 

 boring, well-sinking and the excavation of tanks for water conservation. 

 During recent years sub-artesian water has been found in many localities 

 where it was not supposed it existed, and bores and wells are taking the 

 place of tanks and dams. The Government has taken steps to assist 

 liberally land-holders in the sinking of bores, and consequently very marked 

 improvements have been made in the water supply, but in many districts 

 tanks and wells must still be relied upon to provide water for stock require- 

 ments. Droughts have shown the necessity of providing ample storage, of 

 maintaining the storage in good condition, and of keeping the supply drains 

 in order. 



Site. 



Very careful consideration should be given to the selection of a site for a 

 tank. The most important point is a good catchment, and this, on some 

 holdings, is almost the sole determining factor. In undulating country 

 catchments are generally good, and no difficulty is experienced, but in the 

 level country of the western plains a new settler would do well to secure the 

 advice of a more experienced man. Very often shallow watercourses exist, 

 and the tank should be located on or near these. Roads provide good 

 catchments, and a good flow of water can be obtained off the hard bare 

 patches which exist on the plains. In selecting catchments attention should 

 also be given to the nature of the country ; for instance, a drain running 

 over hard, compact soil will carry more water into the tank than one 

 running over black soil, which develops large cracks during drought periods, 

 and which absorbs a large amount of water before any reaches the tank. 

 Although the experience of old settlers is of great value, even they make 

 mistakes sometimes. Land often appears level when it has a fall of several 

 inches, and in very level country it is often well worth while to have levels 

 taken before fixing the site. 



While preference must be given to the catchment, it is important that the 

 tank should be located in a central position to save the stock from much 

 travelling to and from water. If possible, the site should he near a belt of 

 green timber, as stock come to water in the morning and like to linger round 

 in the shade, taking frequent drinks before moving off in the afternoon. If 

 shade is not available they probably take only one drink in the day, and 

 consequently do not do as well as they otherwise would. 



After locating what is apparently a good site, the nature of the soil should 

 be ascertained. ( On some country a tank will hold well almost anywhere, 

 but in other classes of soil some considerable difficulty is experienced, and 

 recourse must be made in some eases to puddling. The nature of the timber 

 is usually indicative of the character of the subsoil, but is not always 

 reliable. Occasionally the country is patchy ; while the subsoil in portion 

 of the tank is good, a band of a porous character ma}' be struck which will 

 cause a leakage. Before sinking is commenced trial shafts should be sunk 

 to the depth it is proposed to excavate the tank, and if it is considered the 

 country is patchy two or three should be put down. An experienced man 



