general topography of China looks like a 3-level terrace,
and Yunnan lies between the second terraces. The main part
of Yunnan, which is the southern extension of the Qinghai-Tibet
Plateau, belongs to the second terrace. In the northwest,
Yunnan connects-circle of steps, shoping from the northwest
to the southeast, its altitude lowering that is part of the
Nushan Mountain in Deqin County, north-west of Yunnan.The
direct point 76.4meters above sea level, is the confluence
of the Nanxi River and the Yuanjiang River in Hekou County
in south Yunnan. The direct distance from the highest point
to the lowest point is merely 900 kilometers, but the altitude
gap is over 6 kilometers.
The general topography of Yunnan resembles
that of China, highlands in the northwest and lowlands in
the southeast with varied geo-graphical features. Corresponding
to the topography, the rivers run in a fan-shaped distribution
from the northwest to the east, southeast and south. Yunnan
is a mountainous plateau, with 94 percent to the east, southeast
and south. Yunnan is a mountainous plateau, with 94 percent
of hilly land against 6 percent of basins.
Divided by the Yuanjiang valley and
the broad valley in the southern part of the Yunling Mountains,
the topography in the east differs considerably from that
of the west. In the east, it is the Yunnan Plateau, including
the highlands in eastern and central Yunnan - Guizhou Plateau,
and its average altitude is about 2,000 meters above sea level,
The eastern part is characterized by undulating low mountains,
round hills and various types of karstland. The well-known
karst scenic spots are the Stone Forest, the Puzhehei in Qiubei
County, the Duoyi River in Luoping County, the Jiuxiang Cave
in Yiliang County, the Swallow Cave in Jianshui County and
the Alugu Cave in Luxi County. In the west of the dividing
line is the longitudinal valley of the Hengduan Mountains
where peaks alternate with deep gorges, forming a charming
precipitous topography. The most superb is Sanjiangbingliu,
the parallel running of 3 rivers. Generally, the altitude
of Yunnan Province is about 3,000 to 4,000n meters in the
northwest and about 1,500 to 2,200 meters in the southwest.
However, the altitude gets lower to 1,000 or 800 meters near
the borders. Some places are under 500 meters above sea level.
These are the tropical and sub-tropical zones.
The undulating hilly land of Yunnan is spotted by block basins
that are called Bazi as distinguishable from plains. These
flat basins are more fertile with thick soil and with rivers.
These flat basins are more fertile with thick soil and with
rivers running across. They are usually the more developed
districts. In the whole province, there are 1,445 basins with
an area of over one square and 49 of them are over 100 square
kilometers. The biggest basin, with a total area of 771.99
square kilometers, lies in Luliang County. The following 9
basins are the Kunming Basin (763.6 square kilometers). The
Erhai Basin (524.76 square kilometers), the Qujing-Zhanyi
Basin (435.82 square kilo- meters), the Gudong Basin (432.79
square kilometers), the Songming Basin (414,6 square kilometers),
the Yuanjiang Basin (339.99 square kilometers) and the Mengzi
Basin (217 square kilometers).