The Water System of Buenos Aires
The following description of the water system of Buenos Aires, Argentina, and of water works planned, is contained in a recent consular report issued by the U. S., Department of Commerce: The consumption of water per inhabitant, per day, based on various figures already in the hands of the engineers, has been fixed at 300 liters (79.251 gallons). This is considerably above any actual use of water hitherto reported in Buenos Aires, but as the engineers wish their estimate to be tested in the danger zone, they have fixed upon this high estimate for working calculations. Practically all the water for the old area, and for a small zone in the new area, has been supplied from Rio de la Plata. In Flores and Belgrano, the large residence districts in the new area, some water supply has hitherto come from driven wells, but the intention is, and has so far been carried out, to do away with these wells and to supply the entire city from the river itself. The water from the Rio de la Plata has been proved to be remarkably suitable for all purposes to which it can be applied. Both chemical and bacteriological analysis show that however much organic matter there may be in the river water it nevertheless can be easily and absolutely purified by the time it reaches the consumer. This purification takes place by means of sedimentation, coagulation, and filtration in the scientific manner recognized and adopted in many parts of the world. Buenos Aires lies on the edge of the river, with no elevation from which water could be distributed to the city. For that reason it is necessary, after taking water from the river, to pump it to such a height, artifically prepared, as will allow its distribution both to the older and lower buildings and to the newer and loftier buildings of the more modern city. In the old area this was effected by the tanks and other retainers of water in the building on Calle Cordoba, which is one of the interesting places to visit in Buenos Aires. Water was distributed from this center station over an area of 3,000 hectares (7,413 acres), but even this must be reinforced from the new work which is to supply water to the inhabitants of 15,406 hectares (38,068 acres). For this purpose at least four new centers of distribution have to be decided on, although there are now under immediate construction only two of these centers. The first step in all this project was the selection and installation of the new service of the water supply. The site finally chosen was a point in the river practically 1,000 meters (3,280 feet) from the shore, opposite the 3 de Febrero Park. Here will be constructed a water tower, from which an intake tunnel will conduct the water to the pumping stations on shore. Thence the water will pass to the decanting reservoirs. From these reservoirs the water will pass finally to the filter beds, and from there it will be sent to the gravity tanks and to the reserve tanks; a network of water mains will be extended thence to all parts of the city. It is said that the tanks in London have a capacity equal to more than twenty times the water consmumed in one day. In New York this proportion is still greater. In Buenos Aires they have been made necessarily smaller, because the intake system, the excessive price of land, and the lack of natural elevations on which these tanks could be constructed, make the cost prohibitive. But the use of coagulation has overcome this difficulty. The water reservoirs are four in number, rectangular in shape, 105 meters (344 feet) long, and 96 meters (314 feet) wide. There are seven filter beds 105 meters (344 feet) long, 70 meters (229 feet) wide, and 4 meters (13 feet) deep, each divided into three sections and distributed in three groups. The total filtration area is 48,300 square meters, (519,901 square feet), but as two sections at least must be constantly out of service for the purpose of cleansing them, only 43,700 square meters (470,386 square feet) can be considered constantly in service. As the clarification of the water is carried on also by means of coagulation, it is estimated that 250,000 cubic meters (8,828,500 cubic feet) of pure water can be delivered each day for consumption. Provision is made, in the general plan of the work, for proper reserves of filtered water, so that, even in case the filter beds and the coagulation tanks are for the time out of service, there still will be no lack of water for the city. The highest point the water reaches in these new gravity tanks is 70 meters (229 feet) above the plane of comparison adopted for the general level of the municipality. This plane is 30.5 meters (100 feet) below the floor of the peristyle of the cathedral, so that the maximum height of the water is 39.5 meters (129.5 feet) above that point. The highest points of the municipality are 38 meters (124.6 feet) above the general level, and the lowest are 15.5 meters (50.8 feet) below the general level. It is therefore assumed that this new system will be able to supply water to the highest building yet constructed in the city.