The upper valley of the Mendoza begins at around
above mean sea level, and it is U-shaped, of
glacial origin. The river reaches
Uspallata, then crosses the
Precordillera through the
Potrerillos Valley, flows along the
Cacheuta Canyon and reaches the plain. It forms an arc and turns northeast, finally emptying into the ''
, which join the San Juan River, part of the system of the Desaguadero River. (The lagunas de Guanacache
are also called Bañados de Guanacache
in Spanish; please note that "lagunas''" does not translate as "lagoon" which is strictly a maritime term, but as "wetland", akin to "marsh" or similar.) The river has a
mean flow of , and supplies water for the main oasis in the otherwise arid province. Its course through Potrerillos, at about above sea level, features
rapids, which are employed for
rafting (level III–IV on the
International Scale of River Difficulty during the summer). In Potrerillos the river is also
dammed, forming a
reservoir, which feeds a
hydroelectric power station. The
Cacheuta Spa and the
Potrerillos Dam are tourist destinations along the river. Mendoza River irrigates the
Maipú and
Lujan vineyards, located in Mendoza
piedmont, at 30° south latitude. This region hosts 17 percent of the
Mendoza vineyards, and about 360 wineries. == Location ==