Abstract
According to the information obtained from a georeferenced network of piezometers, it was determined the water table depth behavior in the Department of Lavalle and specially in the District of Costa de Araujo. The water table depths were grouped at intervals of 0.5 m, from surface to 2.5 m deep. The minimum and medium depths of each piezometer were calculated from 1983 to 2002 and also the medium depths corresponding to the months of March, June, September and December. The surface for different intervals were represented graphic and numerically by the use of Arc View software. With this information there were made tables of water table depths intervals and based on them, the phreatic risk was classified into low, medium and high assuming 1.5 m as the minimum admissible depth value for perennial crops practices. A discussion on water table salinity and its connection with vine chlorosis is presented.
Results: 32 and 41% of the areas of the District Coast and Dpto. Lavalle, respectively, have the water table between 1.5 and 2.0 m deep, resulting Phreatic Low Risk for the District Coast and for the Middle Dpto. Lavalle; September is more critical with 43 and 40% of the areas of the District Coast and Dpto. Lavalle, respectively, with average groundwater levels between 1.0 and 1.5 m deep, resulting Risk Low water table for that month for the Dstrict Coast and High for the Dpto. Lavalle; the subarea Costa possesses the better conditions of phreatic and edaphic depth for the agriculture of the Department Lavalle; the main network of collectors is insufficient to produce the general depression of the phreatic levels of the Department of Lavalle.