|
1.
Geological Environment
Chongming Island is the largest alluvial sand-island of any river
mouth in China. Dongtan is located at the east end of Chongming
Island (31o30′N and 121o45′E) and it is one of the island's main
deposit zones for silt runoff. It also has the most potential for
growth of any other part of the island. Currently, it is expanding
outwards at 140 meters per year. The terrain of Dongtan is flat
and level, with an altitude of less than 4.2 meters. It is surrounded
on three sides by water. The north side faces the terminus of the
northern branch of the Changjiang River; the southern side opens
to the Beigang (North Port) Water Channel, and the eastern side
to the Changjiang River seafront.
2.
Natural Conditions
(1) Geology and Landforms
Chongming Island was formed from the accumulation of massive silt
deposits flowing down through the Changjiang River and subjected
to the intermingling forces of river and sea. Its terrain is flat
and completely covered by a porous stratum from the Quaternary Period.
There are no hills or mountains, but the terrain is higher in the
northwest and central parts and slightly lower in the southwest
and east.
(2) Climate
Dongtan is located along the seashore of the southern fringes of
the northern subtropics, and it has a marine climate. The temperature
is warm and humid and the four seasons are clearly defined. There
is ample sunshine, with the maximum exposure being in August and
the minimum in February. The total hours of sunlight per year are
2,104. The annual average temperature in Dongtan is 15.3℃, and the
hottest days are in July and August, when the average temperature
is 27.5℃. The coldest days are in January, when the average temperature
is 2.9℃. There is substantial annual rainfall with an annual average
of 1117.1 mm.
3. Resources
(1)Geological
Resources
The total land area of Dongtan is 8468.7 hectares. It consists
of three sectors: the Tuanjiesha block of 2076.7 hectares. (Or 3115
Mu); the Dongwangsha block of 4225.2 hectares (or 63378.5 Mu); and
the newly enclosed beach set aside for cultivation (B Beach) outside
Dongtan of 2166.8 hectares (or 32502 Mu). This land mainly consists
of alluvium from the Changjiang River, with some loam and clay deposits.
Currently, the soil of Dongtan remains unpolluted from heavy metal
deposits or toxic organic compounds, and it is suitable for the
cultivation of 'green' food produce.
(2) Wetland resources
Dongtan is the biggest wetland at the mouth of the Changjiang River
with large silt deposits due to the hydrodynamics of the Yangtze
Delta. The natural wetland spreads around the outside of the dam
built in 1998, which has grown as a typical tide-shoal wetland with
a beach of 3.6 - 4.2 meters high. There are clear borders between
bands of common reeds, dense grass and bare beach, as well as many
tide ditches.

(3) Tourism resources
Dongtan faces the river and is close to the sea. With its natural
and wide landscape, it is a valuable resource for island ecology
tourism. The building symbolizing 'union' at the joining point of
the Changjiang River, the Yellow Sea and the East China Sea provides
an impressive feature for tourists and the area in general offers
unique and advantageous natural conditions suitable for leisure
and sightseeing.
 
(4) Varieties of biological resources
Dongtan sits at the mouth of the Changjiang River, and holds both
terrestrial and aquatic (freshwater and seawater) resources with
great biological diversification. In addition to grain, cotton,
oil, vegetable, flower, wood, melon, fruit, medical materials, livestock,
and poultry, there are also other biological resources, which hold
unique special features, such as:
① Variety of marine life resources: in addition to the 4 main species
of fish which are crucian carp, carp, silver carp, and mackerel,
there are also natural crabs, richfield eel, soft-shelled turtle,
black fish, river shrimp, etc., and the area is the biggest breeding
ground for young crabs and eels in the country.
② Variety of marine fishing resources: there are plentiful amounts
of yellow croaker, hair tail, butterfish, Chinese herring, ink fish,
jellyfish, sea shrimp, swimming crabs, etc.
③ Beach biological resources: the beach contains quantities of clam-like
crustaceans, such as Shihuang, razor, Bangqi, etc. and beach plants
such as reed, reed-bamboo, Zhaliu (a species of willow), and silk
grass, etc.
④ Natural fauna and flora resources: there are 32 species of animals
that are categorized Grade 1 or 2 under national protection, such
as the Chinese Sturgeon, wild swans, and cranes, etc. and some rare
migratory birds such as mandarin duck, large and small swans, white
swans, white neck cranes, and gray cranes, etc. as well as some
natural plant resources such as Chinese flowering quince, dark green
lotus, Asiatic Planlain, and Peilan (a native orchid), etc.
⑤ Native produce: there are more than 20 species of native plants,
such as Chinese cabbages, yellow melon, Dahongpao-chidou (a native
bean which is a red-coated red bean), white hyacinth bean, fragrant
taro, sweet chestnut, white goat, and Chongming narcissus, etc.
(5) Agricultural resources
 
Due to the fact that Dongtan is relatively new land, having been
cultivated for just a few years, and that it lies far from municipal
pollution with little wastage, e.g. sewage, gas waste, or other
waste materials, it is indeed an exceptionally clean area with unpolluted
land, water and air. Based on the results provided by the Shanghai
Environmental Academy from their recent study "Research of
Dongtan and Green Produce Park and its Surrounding Area", data
shows that pollutant content of all types are lower than average
levels, and that the integrated pollution coefficient is 0.59~0.69,
which is Grade 1. CI content in the irrigated water is evidently
lower than before for the south-traverse canal was constructed,
and the salt content in the water is 0.2~0.3‰. This integrated pollution
coefficient is 0.10~0.58, much lower than the Grade 1 average value
of 0.31, and all air pollutant readings met with standard levels,
with an integrated pollution coefficient of 0.12~0.53, which is
again, Grade 1 This meets the requirements for ecologically friendly
('green') marine produce. The environment for ecological agricultural
provides excellent conditions for the production of harmless organic
foods.
 
(6) Marine Life Cultivation Resources
There are rich freshwater and saltwater resources in Dongtan. The
water is flows slow and stably, and is warm and highly fertile.
As the water is relatively low in pollution, there are large amounts
of fresh water fish, waterfowl, and aquatic plants, etc. The temperate
zone to subtropical zone provides a suitable habitat for many saltwater
and upstream fish, shrimp, and crabs. In addition, the area around
Dongtan provides a good feeding ground for many varieties of fish
and crabs, as well as a protected area for winter months and laying
eggs. Resources of germ plasma required for aquatic produce are
also plentiful here and the area is obviously in an ideal position
for fishery and marine produce development.
|