Argentina

Environmental Hydrology Activities - Argentina

IAEH Activity Report

Instituto de Hidrologia de Llanuras
Dr. Eduardo J. Usunoff, Director

I will devote a few paragraphs to offer a brief account of a rather singular hydrogeological feature of vast regions at the central-eastern portion of Argentina, where most of the primary productive activities (i.e. cattle raising, agriculture) are carried out. The negligible surface relief and the moderately humid climate regime (mean annual rainfall of about 1000 mm) causes the overall water budget to be different from that normally found in most regions throughout the world. Indeed, 90-95% of the water budget is embedded in its vertical transfer terms (infiltration, and, mostly, evapotranspiration). In as much as evapotranspiration is very difficult to estimate within reasonable levels of precision, errors are usually large and uncertainties arise whenever values for the effective ground-water recharge are to be assumed.

It appears that recent developments in satellite image processing would help assess regional evapotranspiration, although in many countries such methodologies are hindered by the lack of ready access to such satellite images. Aside from Argentina, China and Hungary are other countries with large flatland areas.

The research team I head has been heavily involved with the hydrological characterization of a typical flat land basin: the Azul Creek Basin, which covers about 9000 km2, right at the center of Buenos Aires province.

As expected, one of the major problems we face is to come up with a justified water budget, particularly because of the difficulties in estimating areal evapotranspiration. In doing so, we concluded that this variable had to be of a magnitude at least equal to that given by the conventional Thornthwaite method. This is contrary to many views published elsewhere, which claim that such an empirical expression overestimates evapotranspiration.

I suppose that our finding will not be shared by many hydrologists. Therefore I would like to hear from those who may agree/disagree with that. I am looking forward to starting an active exchange of ideas, thoughts, suggestions, and so forth. Please contact me through the address shown below.

Eduardo Usunoff

Dr. Eduardo J. Usunoff
Instituto de Hidrologia de Llanuras
Intendente Giraut s/n - C.C. 178
(7300) Azul - Pcia. de Buenos Aires
ARGENTINA
Phone/Fax: +54-281-32666
You may send E-mail directly to Dr. Usunoff from this page at eusunoff@faa.unicen.edu.ar. Don't forget to include your name and address!
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