chapter - Atmospheric and Oceanic Science

Physiography and Hydrology
Table 4.4 shows the characteristics of some tributaries of the Paraguay River.
Table 4.4. Characteristics of main tributaries of the Paraguay River
Sub-basin Station
Pilcomayo
Fortín Nuevo
Pilcomayo
The Pilcomayo River sub-basin (Comisión Trinacional para el desarrollo de la
cuenca del Río Pilcomayo WWWeb) is shared by Argentina, Bolivia and Paraguay.
Its sources are in the Bolivian plateau, in a mountainous area that extends from
Sucre (to the North) up to La Quiaca (to the South), and runs toward the Southeast
through a series of plains up to its outlet at the Paraguay River. This basin is characterized
by its topographical as well as lithological, edaphic, hydrological, climatic,
physiographical and population contrasts.
The Bermejo River sub-basin (Comisión Binacional para el Desarrollo de la
Alta Cuenca del Río Bermejo y el Río Grande de Tarija WWWeb) is located in the
southern end of Bolivia and in the North of Argentina has 123000 km 2 of surface,
with more than 1300 km. The basin of the Bermejo River is divided in two well differentiated
areas: the high basin, where the climatic conditions determine a great
variability in vegetation, and the low basin extremely plane topography and with
dry forests in the West and the prevalence of humid lands and forests in gallery to
the East.
The rivers of the basin present a rainfall control with a season variability very
well defined, reaching 85% of runoff during Summer and low waters between April
and September.
4.4.3. The Uruguay River Sub-basin
The sub-basin of the Uruguay River has an area of total drainage of 365000
km 2 and has its source in the convergence of the Pelotas and Peixe rivers, which
have their origin in the Serra do Mar and Geral, at almost 2000 masl. The Uruguay
River ends in the La Plata River, 2200 km. The hydrological regime of the Uruguay
River is very irregular. The Uruguay River is the only big river of the La Plata system
that is not tributary of the Paraná. Although its basin is bigger than that of the
Iguazu, both share the same features that their large discharges can be caused by
53
Drainage Area Mean Annual
(km 2 ) Volume (m 3 /seg)
130.000 153
Bermejo El Colorado 65.735 396
[Comisión Binacional para el Desarrollo de la Alta Cuenca del Río Bermejo y el Río Grande de Tarija WWWeb, Comisión
Trinacional para el desarrollo de la cuenca del Río Pilcomayo WWWeb]