2. ADMINISTRATIVE UNITS
Long An commune consists of 8
hamlets, including Hamlet 1, 2, 3 and 4, and Xom Trau hamlet, An Lam hamlet and
Bung Mon hamlet.
3. GEOGRAPHY - TOPOGRAPHY
- Geology:
+ Basalt rock: located in the
edge of Long Khanh - Thong Nhat basalt sheet, in the Quaternary geological age.
It is a type of black weathered pored basalt soil.
+ Ancient alluvial: in the
Quaternary geological age, the alluvial sediment of Dong Nai River, with light
mechanical composition.
+ New alluvium: belonging to
Holocene sediments of Dong Nai River.
- Topography: In general, the
commune has two terrain types, divided into two distinct components:
+ High terrain: formed on ancient
alluvial rock and basalt ground, accounting for about 40 percent of the natural
area, located in Hamlet 1, Hamlet 2, Hamlet 3 and An Lam hamlet.
+ Flat terrain: making up 60
percent of the natural area, formed on an old alluvial ground and new alluvium,
located in Xom Goc hamlet, along the Dong Hu stream and Xom Trau hamlet.
4. CLIMATE - HYDROLOGY
- Climate:
+ Long An commune has a monsoon
sub-equatorial climate with steadily high heat throughout the year, high
rainfall and seasonal differentiation.
+ The air temperatures are high
and quite stable, with annual average temperatures ranging from 25 to 26 0C.
+ Average annual humidity is at
78 – 82 percent;
Total sunshine hours: 2,200 -
2,700 hours a year. The dry sunny season accounts for 55 – 56 percent of the
total sunshine hours. Solar radiation reaches 110 - 160 Kcal/cm2 per year.
+ The average annual rainfall is
1,900 mm. Due to high rainfalls but unevenly distributed in different months,
there are two seasons, namely rainy season and dry season.
+ Every year there are two main
seasonal winds: the northeast monsoon in dry season, the southwest monsoon in
rainy season. Average wind speed is between 2.1 and 2.4 m/s, with the maximum at
25.0 m/s.
The average amount of evaporated
water is 1,100 - 1,300 mm. Evaporation in dry months is two to three times
higher than in rainy season.
- Hydrology:
The reservoir on Dong Hu stream
(one hectare wide)
There are three streams running
through the commune, including: 6.5 km long Dong Hu stream, 2.53 km long Trau
stream , Tre stream 10.1 km long (sandwiched by Long An and Long Phuoc). Density
rivers and streams is 0.56 km/km2. On Dong Hu stream, there is one-hectare wide
Long An dam, providing irrigation for about 375 hectare of rice in Xom Trau.
According to the Geology –
Hydrology Federation, groundwater in Long Thanh - Nhon Trach area is of good
quality, and iron content is not very high, so water there is mainly exploited.