Vol. I, no. 3, July-september, 2010

• L. Carolina Távara-Espinoza
• Eugenio Sanz

In a short stretch of its headwaters, the base flow of the River Duero increases by several m³/s as it traverses some Mesozoic carbonate outcrops. This is of special importance during the dry season, when the majority of the base flow of the river proceeds from springs in this reach. The outcrops correspond to one of two confined calcareous aquifers that developed in parallel but which are not hydraulically connected because of an impermeable layer. Together, they constitute the aquifer system of the Gormaz Springs. The system is still in its natural regime and is hardly exploited.

• Marcelo E. Lascano-Kezič

Location analysis for reservoir implementation in subtropical and tropical environments must thoroughly consider the probable progression of the silt-in processes according to a river’s sediment load. This article intends to point out that restrictions on the length of the operating life of reservoirs may affect dam planning on main tributaries, but that its effect would be rather less significant for projects on secondary tributaries with headwaters at lower external crests with less pronounced slopes.

• Carlos Fuentes
• Carlos Chávez
• Felipe Zataráin

An analytical solution of the Richards equation is deduced using Green and Ampt hypotheses to describe the infiltration in soils with a shallow water table. A linear initial moisture profile is assumed, so that the minimum value is at the soil surface and the maximum value at the water table level. A linear variation of the driver pressure is accepted, it is maximum at the soil surface and zero at the water table level.

• Enrique González-Sosa
• Carlos A. Mastachi-Loza
• J. Bernardo Rivera-Vázquez
• Alfonso Gutiérrez-López
• Jacqueline Lafragua
• Aurelio Guevara-Escobar

Annual evaporation in the Lake Patzcuaro watershed was partitioned as follows: evapotranspiration of terrestrial vegetation, interception losses, lake evaporation and evapotranspiration of aquatic plants. Terrestrial evapotranspiration was estimated from the records of six stations and seven atmometers (ETgage). Lake evaporation was measured with the BREB method.

• Serge Tamari
• Ariosto Aguilar-Chávez

It is often desirable to monitor the water level in water bodies with an uncertainty smaller than ± 5 mm. In this context, the goal of this work was to test two models of a “new generation” of submersible pressure-transducers, i.e. instruments with an integrated temperature sensor and a datalogger that automatically corrects the effect of temperature on the pressure-transducer output. The experimental results and some theoretical considerations suggest that these transducers can be used to monitor the water level in drinking water tanks for weeks with an uncertainty between ± 5 and ± 7 mm [p = 0.95], provided that the water level is smaller than 5 m, and that the water temperature remains within a range of ± 5 °C.