16 AGRICULTURE IN THE SAHARA DESERT. 



WATER SUPPLY. 



There is no surface water in the whole Souf country, excepting, 

 possibly, a small sebka, or salt pond, of which the writer was told, 

 but which he did not see. There are no natural springs, although 

 ground water is everywhere very near the surface in the hollows- 

 among the dunes. It is said to occur sometimes in strata of pure 

 quartz sand, sometimes in gypseous sand. The distance to standing 

 water is said to reach as much as 40 feet in ditferent j^arts of the 

 region, although averaging considerably less; but in the bottoms 

 of the basins in which date palms are grown it is encountered often 

 at a depth of only 2 or 3 feet below the surface of the soil, thanks to 

 the extensive excavation that has been done. In one garden, near 

 the town of El Oued, the writer saw water standing at a depth of 

 feet in a large hole that had been dug to receive manure. The Souf 

 oases are believed to mark the course of a buried Quaternary stream ; 

 Oued Souf means " murmuring river." " 



As we shall presently see, the date palm is not irrigated in the Souf 

 country, receiving at most a few waterings l)y hand during the first 

 summer after planting. In almost all the gardens, however, shallow 

 w:ells occur,^ the water of which is used for household purposes and 

 for irrigating small plats of garden vegetables. (PI. Ill, fig. 3.) 

 These are generally situated on the slope of the bordering dunes, 10 

 feet or less above the bottom of the basin, and water stands in them 

 at a depth of 10 to 16 feet. In the town of El Oued the wells are 

 much deeper than in the gardens, water standing in them at 30 to 40 

 feet. All this water is under a slight pressure, rising in the wells 

 about 1.5 feet higher than the general water table. Sinall gardens of 

 vegetables and tobacco,^ irrigated from deeper wells, are also located 

 in some parts of the region far above the bottoms of the ])asins. Prac- 

 tically no grain is raised, wheat and barley being brought by caravan 

 from other parts of Algeria and from Tunis, to be exchanged for 

 dates. 



« It is difficult to obtain a very satisfactory idea as to the distribution of tbe 

 ground water in the Souf region, its depth at various points, and the amount of 

 excavation necessary to enable the roots of the palms to reach it easily. The 

 natives themselves give the most conflicting answers to questions upon this 

 subject, and there are serious discrepancies in the accounts that have been 

 published by French authorities upon irrigation. The whole matter evidently 

 needs to be carefully studied by comjietent hydrographers, a study which is cer- 

 tainly warranted by the rarity of this type of agriculture. 



6 In 1883 RoUand estimated that there were 4,4.31 wells in the Souf region. 



'Tobacco growing, which is unrestricted in Algeria, is a protttable Industry in 

 the Souf country on account of that region's nearness to the frontier of Tunis, 

 where the growing of this crop is forbidden by law and where the selling of 

 tobacco is controlled by the government. Agents of the Tunisian tobacco 

 monopoly frequently visit the Oued Souf to purchase supplies. 



