III.-AQUEDUCT OF SALDAN OF THE NORTHERN CANAL OF THE IRRIGATION WORKS OF THE RIO PRIMERO, PROVINCE OF CORDOBA.
Report on Irrigation.

THE IRRIGATION SUPPLIES OF THE REPUBLIC.

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or earth embankments, which sometimes in sudden freshets are swept away with great damage, thus leaving the people of the district, until they are repaired, without the means of irrigating their lands. I give below the various sources of the water supply.

JUJUY.-This province, which borders on Bolivia, is irrigated at various points by the waters of the river San Francisco, which, making a semi-circle through the southern valleys, finally empties into the Rio Vemejo. While it is the only considerable stream in the province, there are a large number of small mountain riverlets, from which channels also have been dug, and which greatly assist the necessities of agricult

ure.

SALTA. On the other hand, this province is supplied with water for irrigating purposes from no less than three large rivers, the Juramento, the San Francisco, and the Vermijo, and by a large number of mountain streams, which are throughout their length utilized for agricultural purposes.

TUCUMAN.-Owing to the chains of mountains which longitudinally pass through the western portions of Tucuman, this province likewise is quite well supplied with water for irrigation purposes; on the south, the streams from the heights of the Aconquija range, from the river San Francisco, and on the east the river Sali, afterwards called the Dulce. These two rivers, together with an innumerable number of mountain riverlets, furnish an abundance of water for irrigation purposes, and nearly all the farms and sugar plantations are thus supplied through the means of ordinary conduits.

SANTIAGO DEL ESTERO.-In this province, the principal source of the waters for irrigating purposes is the river Juramento, afterwards called Salado, which flows along the northern and eastern borders. As far as Sepulturas the river is well banked and both sides are covered with fine farms and sugar plantations, the artificial watering which they receive from the stream producing a marvelous fertility in lands which otherwise would be perfectly barren. Beyond that point, however, it spreads out into marshes or esteros (whence the name of the province) over a country which is unfit for cultivation. Another considerable water course is the river Dulce, which, after leaving Tucuman, flows diagonally through the province, passing by the city of Santiago. In that vicinity it is well banked, and by means of a series of canals furnishes an abundance of water to the estancias and sugar farms on each side. Afterwards, turning to the southeast, it reaches the Salinas or great salt desert, where no vegetation can exist. Beyond this its several channels unite again and forms what is called the Saladillo. Along this stream are to be found spots or "oases in the desert" which have been redeemed by means of irrigating canals, thence coursing over a barren plain the river finally loses itself in an immense salt swamp called Los Porongos.

CATAMARCA. This has no large water courses, though it is crossed by several small rivers, of which the principal are Santa Maria, the Paelen, and the Piedra Blanca, the two last named forming the Rio del Valle, on which the city of Catamarca is located. These streams and their affluents, and indeed every gorge and valley in the province down which courses a mountain torrent, are utilized ere they are swallowed up in the sands, for the purposes of irrigation. But even then the water supply is so inadequate, that there are throughout the province immense districts without water courses and without rain, which must continue to be little less than sterile deserts.

RIOJA.-Its only river of importance is the Vermijo, and this waters only a very small portion of its surface. This river, coming down from the eternal snows of Mount Boneti, traverses the fruitful valley of Jaque, is increased by the torrents which come from the Valle-Hermoso, and turning its course to the south to receive the surplus waters of the valley of Jacal, finally in latitude 32 degrees loses itself in the sand before reaching the lagunas of Guanacache. Throughout its course it affords excellent facilities by means of sluices for irrigation, but the volume of water is wholly insufficient to meet the requirements of the people, and during the summer months, for want of moisture, there are but few places which escape the wide-spread drought. Wherever there is a thread of water, however, coming down from the Sierras, it has been utilized for irrigation, and in the last few years the Government has been boring artesian wells in the hope of obtaining a better supply of water, but thus far with very little success.

SAN LUIZ.-This province is as poorly supplied with water as Rioja. The only river of any importance is the Rio Quinto, which comes down from the mountains in a series of cascades, and after a southeast course is finally lost in the pampa, in latitude 34 degrees, in an immense saltmarsh called Juncal. There are several small streams whose waters are also, by means of dams and canals, utilized for the purposes of irrigation, but the great want in this province is more water; for although in good seasons there is rain-fall enough for the crops, yet this can not be depended on, and an adequate harvest is only certain in those parts where they have streams for irrigation.

SAN JUAN. This province is in the midst of the rivers which compose the water system of the Cordilleras. The most northward of these is the Colorado, which is fed by several affluents from the far western Sierras. The second is the Vermejo Chico, which also is formed by several affluents in the snow-covered peaks of Copiapo, at whose foot are a series of magnificent farming districts, all watered by canals from these mountain streams. This river afterwards, turning to the south as I have said, makes its way towards the Laguna Guanacache, but is lost before it gets there. The third and most important of the group is the river San Juan, which has its source in the summits of the Cordilleras, in two affluents, and flowing to the east, down the valley of Pismento, cuts through the mountains and, after passing by the city of San Juan, turns to the south and empties into Lake Guanacache. Formerly, on the breaking up of the snows, the floods which came down this river caused most destructive inundations in the vicinity of the city, and sometimes devastated leagues upon leagues of the most cultivated parts of the valley. To guard against this, an immense dyke has been constructed which acts as a reservoir for holding the water during the summer months. From this reservoir have been constructed numberless distributing canals and conduits all along that beautiful valley; and the water is now so abundant that there is sufficient for steady streams along the gutters of the city. The San Juan all along its course, however, offers marvelous facilities for irrigation. At Murallon, its altitude is 800 meters, while at Lake Guanacache its altitude is only 600 meters, thus giving a fall of 200 meters in a distance of not over 40 miles in a straight line. The river, however, is wonderfully crooked, and affords water for an unlimited number of canals and conduits for fertilizing all the adjacent country. Besides this all the small streams and rivulets which find their way down from the mountains are utilized for watering the lands along which they course-indeed they are entirely absorbed for agricultural purposes.