The Paraneña Region
The Paraneña region extends from the Río Paraguay eastward to
the Río Paraná, which forms the border with Brazil and Argentina.
The eastern hills and mountains, an extension of a plateau in
southern Brazil, dominate the region, whose highest point is about
700 meters above sea level. The Paraneña region also has spacious
plains, broad valleys, and lowlands. About 80 percent of the region
is below 300 meters in elevation; the lowest elevation, 55 meters,
is found in the extreme south at the confluence of the Río Paraguay
and Río Paraná.
The Paraneña region is drained primarily by rivers that flow
westward to the Río Paraguay, although some rivers flow eastward to
the Río Paraná. Low-lying meadows, subject to floods, separate the
eastern mountains from the Río Paraguay.
The Paraneña region as a whole naturally divides into five
physiographic subregions: the Paraná Plateau, the Northern Upland,
the Central Hill Belt, the Central Lowland, and the Ñeembucú Plain.
In the east, the heavily wooded Paraná Plateau occupies one-third
of the region and extends its full length from north to south and
up to 145 kilometers westward from the Brazilian and Argentine
borders. The Paraná Plateau's western edge is defined by an
escarpment that descends from an elevation of about 460 meters in
the north to about 180 meters at the subregion's southern
extremity. The plateau slopes moderately to east and south, its
remarkably uniform surface interrupted only by the narrow valleys
carved by the westward-flowing tributaries of the Río Paraná.
The Northern Upland, the Central Hill Belt, and the Central
Lowland constitute the lower terrain lying between the escarpment
and the Río Paraguay. The first of these eroded extensions
stretching westward of the Paraná Plateau--the Northern Upland--
occupies the portion northward from the Río Aquidabán to the Río
Apa on the Brazilian border. For the most part it consists of a
rolling plateau about 180 meters above sea level and 76 to 90
meters above the plain farther to the south. The Central Hill Belt
encompasses the area in the vicinity of Asunción. Although nearly
flat surfaces are not lacking in this subregion, the rolling
terrain is extremely uneven. Small, isolated peaks are numerous,
and it is here that the only lakes of any size are found. Between
these two upland subregions is the Central Lowland, an area of low
elevation and relief, sloping gently upward from the Río Paraguay
toward the Paraná Plateau. The valleys of the Central Lowland's
westward-flowing rivers are broad and shallow, and periodic
flooding of their courses creates seasonal swamps. This subregion's
most conspicuous features are its flat-topped hills, which project
six to nine meters from the grassy plain. Thickly forested, these
hills cover areas ranging from a hectare to several square
kilometers. Apparently the weathered remnants of rock related to
geological formations farther to the east, these hills are called
islas de monte (mountain islands), and their margins are
known as costas (coasts).
The remaining subregion--the Ñeembucú Plain--is in the southwest
corner of the Paraneña region. This alluvial flatland has a slight
westerly-southwesterly slope obscured by gentle undulations. The
Río Tebicuary--a major tributary of the Río Paraguay -- bisects the
swampy lowland, which is broken in its central portion by rounded
swells of land up to three meters in height.
The main orographic features of the Paraneña region include the
Cordillera de Amambay, the Cordillera de Mbaracayú, and the
Cordillera de Caaguazú. The Cordillera de Amambay extends from the
northeast corner of the region south and slightly east along the
Brazilian border. The average height of the mountains is 400 meters
above sea level, although the highest point reaches 700 meters. The
main chain is 200 kilometers long and has smaller branches that
extend to the west and die out along the banks of the Río Paraguay
in the Northern Upland.
The Cordillera de Amambay merges with the Cordillera de
Mbaracayú, which reaches eastward 120 kilometers to the Río Paraná.
The average height of this mountain chain is 200 meters; the
highest point of the chain, 500 meters, is within Brazilian
territory. The Río Paraná forms the Salto del Guairá waterfall
where it cuts through the mountains of the Cordillera de Mbaracayú
to enter Paraguayan territory.
The Cordillera de Caaguazú rises where the other two main
mountain ranges meet and extends south, with an average height of
400 meters. Its highest point is Cerro de San Joaquín, which
reaches 500 meters above sea level. This chain is not a continuous
massif but is interrupted by hills and undulations covered with
forests and meadows. The Cordillera de Caaguazú reaches westward
from the Paraná Plateau into the Central Hill Belt.
A lesser mountain chain, the Serranía de Mbaracayú, also rises
at the point where the Cordillera de Amambay and Cordillera de
Mbaracayú meet. The Serranía de Mbaracayú extends east and then
south to parallel the Río Paraná; the mountain chain has an average
height of 500 meters.
Data as of December 1988