VIEN KHOA HOC VA CONG NGHE VIET NAM
VIỆN HẢI DƯƠNG HỌC TUYỂN TẬP TÀI NGUYÊN VÀ MÔI TRƯỜNG BIỂN TẬP X - Ban biên tập:
Trưởng ban: PGS., TS Nguyễn Văn Tiến
Trang 3MUC LUC
Lời nói đầu
1 45 năm hoạt động và phát triển của Phân viện Hải dương học tại Hải
Phòng (1959 - 2004)
Nguyễn Văn Tiến
2 Coastal Erosion and Sedimentation in Vietnam
Tran Duc Thanh, Pham Huy Tien,
Bui Hong Long, Nguyen Van Cu 3 Researches in Estuarine Environment and Ecosystem of Red River: An
Overview on Activities and Results
Tran Duc Thanh 4 Geological Environment of the Tienyen — Hacoi Bay
Nguyen Huu Cu, Nguyen Ngoc, Tran Duc Thanh, Dinh Van Huy, Nguyen Quang Tuan, Nguyen Vu Tuan, Nguyen Thi Phuong Hoa, Nguyen Thi Kim Anh, Dang Hoai Nhon Studies on Seaweeds in Vietnam
ov >
Nguyen Van Tien, Nguyen Huu Dai 6 Researches in Distribution of Vietnamese Seagrasses
Nguyen Van Tien 7 Cau tric va tiến hoá địa chất vùng bãi bồi ven biển Nghĩa Hưng
Nguyễn Hữu Cứ, Trần Đúc Thạnh, Nguyễn Vũ Tuấn, Nguyễn Quang Tuấn, Đặng Hoài Nhơn, Nguyễn Thị Kim Anh, Bùi Văn Vượng 8 Đặc trưng hình thái - động lực và biến dạng bờ Hải Hậu, Nam Định
Đỉnh Văn Huy, Đỗ Đình Chiến,
Trân Đức Thạnh, Bùi Văn Vượng
9 Một sưu tập hoá thạch trùng lỗ (Foramminifera) Mioxen muộn ít được biết
đến ở khu vực bồn trầm tích Đệ tam ven biển Đồng Hới (Quảng Bình)
Nguyễn Ngọc, Nguyễn Hữu Cử
10 Bước đầu đánh giá tác động của hồ Hoà Bình đối với nguồn lợi cá biển
ven bờ
Trần Đức Thanh, Dé Dinh Chién 11 Khả năng tác động của một số hình thức nuôi thuỷ sản đến môi trường
vùng biển ven bờ Hải Phòng
Lưu Văn Diệu
12 Hiện trạng, xu thế biến đổi mơi trường địa hố trầm tích đầm nuôi tại
vùng ven biển Hải Phòng
Nguyễn Thị Thu Hiên, Nguyễn Đức Cự 13 Một số dẫn liệu về ảnh hưởng của các muối đinh dưỡng (PO.”, NOÿ) đối
với mật độ tế bào quần xã thực vật phù du tại vịnh Hạ Long
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RESEARCHES IN ESTUARINE ENVIRONMENT AND ECOSYSTEM OF THE RED RIVER: AN OVERVIEW ON ACTIVITIES AND RESULTS
Tran Duc Thanh
1 INTRODUCTION
Stretching on the length of over 150km, the Red River Estuary (RRE) in
located in the western coastal zone of the Tonkin Gulf The Red River is second
largest river in Vietnam and one of the five largest rivers on the of East Asia
coast Its catchment covers parts of China and Vietnam and its water and
sediment discharges greatly influence the Tonkin Gulf of these countries Due to
the rich natural resources and favorable natural conditions, RRE has become an
area of active economic development and high population density Out of 78
million Vietnam people, are over 24 million live in the Red River basin, including
over 17 million people in its delta There are many great industrial zones in the
Red River Basin such as Viettri, Thainguyen, Hanoi, Haiphong and Namdinh, Its
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2 RESEARCH ACTIVITIES 2.1 Research Organization
Over the last 40 years, mainly government research institutions of Vietnam
have investigated RRE Only few international cooperation researches of mall
seale for the purpose of natural resources and environment protection have been done in this estuary, recently Correspondingly, most of fund supports to the research projects have been supplied from Vietnam Government Mostly, the
institutions interested in research of RRE are under the administrative
management of National Centre for Natural Science and Technology (NCST), Ministry of Fishery (MOF) Ministry of Education and Training (MET), Ministry
of Agricultural and Rural Development (MARD) and General Department of Meteorology and Hydrology (GDMH) From them, the key institutions can be listed as Haiphong Institute of Oceanology (HIO) and Institute of Geography (IG)
under NCST, Research Institute of Marine Fishery (RIMF) under MOF and National University Hanoi (VNUH) under MET -
The researches concerning RRE have been implemented in forms of independent projects or projects belonging to the national research programmes Generally, the independent projects are short term of implementation and resolve the important objectives, which are emerged in the certain sit The researches implemented belong to projects in two systems of national research programmes: the National Programmes for Marine Research and National Programmes for Environment Protection, which are organized every five years Many research projects of national programmes mentioned RRE, however, most of them have covered very large coastal space in which RRE is a part only (MOSTE, 1999) It seems that each project has resolved its specific objectives For this reason, there have been very few integrated researches in Red River Basin generally and RRE particularly Beside research projects, under the management of GDMH, a system of observation stations of mainland and marine meteorology and hydrology in the Red River Basin is operating A system of coastal stations of environment observation and analysis under the management of National Environment Agency (NEA/MOSTE) has been operating since 1993 Haiphong Institute of Oceanology is responsible for manage the stations at RRE of this
system (NEA\MOSTE, 1998)
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2.2 Research Progress
2.2.1 Before 1981
There were very few researches in RRE during the French time before 1954, except some studies of deltaic geography However, the observed data on Marine Meteo-Hydrology at Hon Dau Station built in 1923 in the northern part of RRE
and some observed data on river hydrology of Red River are precious historic
data (Sinh, N.N et al, 1985), From 1955 to1980, the coastal and estuarine researches were not paid a special attention, and the most important projects of multidiscipline surveys and fishing ground investigations focused on the offshore area of Tonkin Gulf before 1975 or south part of South China Sea from 1976-1980 (Thanh, D.N 1998) However, a few relevant data on the Red River Basin were measured in some projects For example, in the join multidiscipline survey programme from 1959 to1965, some survey stations on biology, hydrology and
sediments were located at Red River and its estuary China - Vietnam (VCST,
1965) In this period, there were not any big research project on estuarine ecosystem and nutrient flux in RRE, but small projects implemented by HIO and RIMF The researches focused on the intertidal zone, and on flora and fauna, included algae, phytoplanktons, zooplanktons, zoobenthos and fishes, and fishery resources for the purpose of catching and brackish aquaculture The studies of nutrients were not as much as those of biological factors and fishery resources
One of the significant works implemented by HIO from 1976-1977 was a survey
of bottom topography and sediments in Haiphong- Nghetinh coastal marine area, including whole subtidal zone of RRE Few data on chemical content of bottom sediments, including ©, P and N were measured in this work (HIO, 1977)
2.2.2 From 1981 to now
In this period, researches in RRE included the themes of landforms estuarine dynamics and succession, biological productivity, biodiversity, nutrients, pollution, protection of natural resources and environment .etc have been paid more and more attention HIO, IG, VNUH and some other institutions have implemented the most important researches Some international cooperative projects for the purpose of natural protection and community assistance have been implemented The key research projects concerning RRE have been under the conduction of National Programmes for Marine Research and National Programmes for Environment Protection,
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(Thanh, D.N., 1991, 1998) They were specialized in issues of natural factors, meteo-hydrological processes, estuarine dynamics, natural resources, suitable use of intertidal zone or estuarine ecosystem So that, there were not an integrated picture for a natural system of RRE, generally and an ecosystem of
RRE, particularly In this period, two interesting projects on “Investigation and estimation of natural condition and resources in Vietnam coastal zone” coded 48.06.14 and “Investigation of environment and natural resources of Thai Binh
coastal province” coded 52.02.02 were implemented For the first time, the project
coded 48.06.14 determined the boundary of RRE with its particulars of ecosystem and the project coded 52.02.02 had a success in integrated and detail research in
a part of RRE Besides, the project on “Studying typical coastal ecosystems in Vietnam and proposing a orientation for suitable use” coded 48B.04.02 were a good example for research in intertidal ecosystem of RRE in term of succession, community structure and use of living resources The research in mangrove ecosystem by the VNUH and HIO attained some significant achievements
Thanks to the result of scientific researches, a tropical estuarine wetland of world’s importance named Xuanthuy in RRE were recognized in 1989 Until
now, it is the unique Ramsar Site in Vietnam (Cach, N.V., 1999) >
From 1991 up to now, a great number of researches in terms of estuarine processes, biodiversity, nutrients, primary productivity, wetland ecology pollution, environment impact of human activities, suitable use of natural resources and coastal management have improved the knowledge on RRE at a
higher level From 1993, the observation activity of environment factors included
nutrients, pollutants and environmental biology at some stations in RRE has been done regularly by HIO every three months The impact of human activities in both watershed and in sit on the environment and ecosystem of RRE has emphasized in the research projects, particularly contaminants from landbase
(Ninh, P.V., 1995; Dieu, L.V & Hoa, N.T.P., 2001) and damming for hydropower
reservoirs (Thanh, T.D., 2001) Also, over catching, lowland reclamation for agriculture and brackish aquaculture and destroying mangroves have been paid
more attention in the researches
3 PRELIMINARY KNOWLEDGE
3.1 Climate and Hydrology
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directions which are parallel to the coast reach a frequency of 70 - 80% from
December - January In SW monsoon during May - September, the average speed
of wind is from 4 to 5m/s with the prevailing wind of SE, S and E directions
Every year, the RRE is under the influence of 2 - 5 typhoons happening from
June - September, generally with the wind speed reaching 45 - 50m/s (Huy, D.V., Cu, N.H, 2000) Some typhoons occurred in the spring tide combining with
typhoon surge have destroyed the coast heavily As a calculation, the surge range reaches 1m every 2 typhoons, 2m every 5 typhoons and maximum 3m (Ninh, P.V, et al., 1992) When the typhoon surge falling in spring tide, the sea level can rise
up 5 - 6m and very strong wave can break out sea dikes and make coastal deformation deeply
The basin of Red River is 155 thousand sq km in area, of which 55% is’in Chinese territory Yearly, its discharge is estimated at 125 cub km water, 116 million ton sediments and 70 million ton dissolved matters (Pho, N.V, 1984)
The diurnal tide is nearly regular with a maximum range of 3,5 - 4m (Thuy, N.N, 1984) In comparison with the time of flood tide, the time of ebb tide is somewhat longer in NE margin and two times in SW margin of RRE The tide
current is of 20 - 30cm/s in average speed, maximum 60cm/s for ebb tide and
50cm/s for flood tide The coastal circulation is of 25 - 30cm/s and SW ward in dry
season, and 15 - 20cm/s and NE ward in rainy season (Huy, D.V & Cu, N.H,
2000) The prevailing wave directions are NE and E in winter, and SE and E in summer The mean wave height is of 0.88m, maximum 2m during NE wind season and 5m during typhoons (Hung, N.M., 1992) In the NE part of RRE, the sea level rise at rate of 2.24mm/year was measured (Thuy, N.N., & Khuoc, B.D.,
1994)
3.2 Morphology, Sediments and Estuarine Development
With a shoreline length of over150km, RRE is located on the western coast
of the Gulf of Tonkin, which is semi closed in shape, and shallow and gentle sloping The total area of Red River Delta is about 17,000km’ Its estuary is considered to have two zones such as the subaerial delta of 5,000 sq km in area and the submerged delta (delta front) of over 1,000 sq km in area The subearial delta consisting of the diked delta part of 4,500 sq km in area and from 1.0 -
1.5m high above mean sea level (MSL), and the intertidal zone of over 500 sq km
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wave
RRE has developed on the base of Cenozoic depression with Tertiary
sediments up to 5,000m in thickness and Quaternary sediments up to 250m in
thickness The Holocene sedimentary thickness is generally 30m, maximum 60m (Tiep, N.T., 1994) The coastal sediments of RRE consist of different kinds from clay mud to fine sand They belong to marine, marine - marsh and alluvial - marine origins The marine sediments are deposited by the dynamical factors of wave, tide and coastal circulation The alluvial - marine sediments are deposited by river and tide The mangroves play an important role to the deposition of marsh sediments
The estuarine development is determined by not only the dynamical
correlation of river — tide-wave, but also the role of mangroves (Thanh, T.D et al.1984; Thanh T.D et al 1991) A great volume of sediments discharged from river are concentrated closely to the coast and deposited on the shạ]low estuary that leads to the strong deposition Along shore, the suspended sediments originated from Red River are transported out of RRE in very far distance SW ward, about 24km for the sand drift and 250km for the mud drift Every year, the shoreline moves quickly seaward at the mean rate of 25m, maximum 120m However, the estuarine accretion is irregular and first four coastal lengths are eroded with the mean rate of 7m/year maximum 30 m/year Over the last 50
years, the high tidal flats has expanded 386 ha/year, eroded 25 ha/year and
balanced an expansion of 361 ha/year The human activities, especially building the dikes, reclaiming the land for agriculture and aquaculture, constructing the dams, dredging the channels ete have large influence on the estuarine development (Thanh, T.D et al., 1996; Thanh, T.D et al., 1997)
3.3 Flora, Fauna and Living Resources 3.3.1 Flora and Fauna
Bio-communities living in aquatic ecosystems in the Red River basin are
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27 precious and rare species of fishes and Ø1 precious and rare species of aquatic
invertebrate, which have been included into the list of preserved species of the
Red Book of Vietnam (Yen, M.D 1995) The brackish and marine flora consist of 12 species of mangroves, 4 species brackish and sea grasses, 23 species of algae, and 185 species of phytoplanktons of which there are 9 are harmful including the toxic species with high density Protocentrum micans The phytoplankton has a density of 10°-10° cell/ cub m (Thuoe, C.V 1996) From mangroves, Kandelia candel, Aegiceras cornicultatum and Sonneratia caseolaris are most expansive The brackish grasses as Cyperus sp and Cyperus malaccensis have an expansive distribution in the tidal flats The brackish and marine fauna include 70 species of zooplankton, 202 species of zoobenthos including 42 species of Polychaeta, 89 species of Crustacean, 68 species of Mollusks and 3 other species, 207 species of fish, 181 birds and some species of mammals, reptiles and amphibians The zooplankton has a density of 1,014 individuals/cub.m (Thu, N.T., 1996) The
zoobenthos is high in density of 50 — 2,190 individuals/sq.m and biomass of 30 -
220 g/sq.m in the mangrove area (Trong, P.D., 1999)
Locating at the mouth of Red River, Ramsar Site named Xuan Thuy was recognized as the wetland of world’s importance in 1989 It is the unique Ramsar Site in Vietnam now, typical for mangrove wetland and very ‘igh in biodiversity
with the great number of species including many specious and rare ones Its
species list includes 95 species of vascular plants, 111 phytoplanktons, 65 zooplanktons, 200 zoobenthos, 56 fishes, 181 birds, and some mammals, reptiles and amphibians From the bird fauna, there are 99 migratory species and 44 waterfowl species and the birds numbered up to 40,000 individuals, sometimes
(Cach, N.V 1999)
3.3.2, Nutrients and Primary Productivity
An initial estimate shows that every year 14,860 ton PO}: 24,602 ton NO; are transported into the estuary by the Red River's flow (Ninh et al., 1995) Every year RRE receives 40,296 ton DIN (NHj, NO; and NO;) and 17,600 ton
dissolved silica (SiO?; and 1,066 ton DIN (NO; and NO;) from river, and the
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Hoa., 2001).The nutrients in surface sediments in RRE are estimated as rich in organic carbon and nitrogen and medium in phosphorus In sediments of mangrove swamps and tidal flats, the total organic carbon contents are 1.2% and 0.4%, respectively; the total nitrogen- 0.135% and 0.099%, and the total phosphorus- 0.115% and 0.073%, respectively (Hoi, N.C 1995)
It is estimated that the primary production in mangrove ecosystem is
4.200gC/m”/year (Cu N.D 2001) and the primary of phytoplankton 150mgC/m*/day (Bo, D & Cu, N.D., 1996)
3.3.8 Living Resources and Utilization
The yearly accreted land in RRE is precious resources for development of settlement areas, agriculture, brackish aquaculture and salt making The tidal wetland and the living resources included fishery production and the biodiversity are the most important natural resources in RRE Until now, there are about 9,000ha mangroves From 1958 to 1994, an area of 16 thousand hectares of tidal wetland was reclaimed for agriculture and over 900 ha for salt making Now, there are 8 thousand hectares of the brackish aquaculture ponds built mainly in the former mangrove swamps (Cu, N.D., 1996; Huy, D.V & @u, N.H., 2000) Almost all aquaculture areas are for extensive and improved extensive and only small ones for semi-intensive Fishes, shrimps, crabs, mollusks and algae are main objectives in the aquaculture brackish ponds The aquaculture productivity is low, for example a shrimp pond gives, 62kg/ha/year for extensive aquaculture, 157kg/ha/year for improved extensive and 470 kg/ha/year for semi-intensive The productivity of semi-intensive aquaculture is of 800 kg/ha/year for crabs, 220 kg/ha/year for fishes, and 810 dried kg/ha/year for algae of Glacillaria
The annual captures production of Red River delta is about 4,000 tones of fresh water fishes and 40,000 tones of brackish and marine product (Yen, M.D.1995) The fishery production mainly in coastal water at less than 30 metre
depth has been decreased in catching efficiency
3.4 Human Activities and Environmental Problems
The human activities in both catchment and in situ have a negative impact on the ecosystem and environment of RRE A large part of the tidal floodplain, including the mangrove marshes has been reclaimed for agriculture as well aquaculture as An area of 24,000 hectares of the tidal flood plain in the RRD was
reclaimed from 1958 to1995 During this period, 985 ha/year of tidal flood plain
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seaward accretion (Thanh, T.D, et al., 2001) Destroyed by the land reclamation for agriculture and aquaculture, the decrease of mangroves has speeded up the coastal erosion and lose habitat, During the last thousand years, a great system of dikes has been built to protect the plain and its inhabitants from river and ocean floods (Dam, N.K , 1962) There are 3,000 km of river dikes and 1,500 km of sea dikes, all in RRD The dikes divide the RRD into compartments, which are lower than the rising sea level A great volume of river water is needed for irrigation every year, for example, 7.4 billion m’ in 1990, in the RRD (World
Bank, 1996) The demand for irrigation water in the RRD, from 25% to 50% of the
river's water discharge is a pressure during the dry season that leads to a large decrease in water discharge to the coastal zone The chemical fertilizers and the pesticides including DDT, Lindane, Monitor, and Wofatox have been used in cultivation Their residues have been transported by rivers to RRE and”
accumulated in the bottom sediments with high concentrations (Cu, N,D, 1999),
Cultivation, logging, and fire have destroyed upstream forests (Cuong, N.M.1997) The damage of upstream forest changes water and suspended sedimentary distribution with the time that has impacted to the natural evolution of RRE The rivers have been dammed to create many reservoirs in the watersheds and coastal plains for irrigation and hydroelecéric power The largest, Hoabinh Reservoir, was built in 1987 on the Da River, which is the largest tributary of the Red River, The Hoabinh reservoir covers an area of 208 km” and
holds 9.5 billion m* of water, Annually, 48 million ton of sediments, equal to 83%
of the suspended-sediment load, are transported into the reservoir and deposited An even larger reservoir, of 440km? to be named Son La, which be is planned in
upper Hoabinh (Thanh, T.D., 2001) A great volume of wastewater, most of which
is left untreated, is dumped into the rivers and discharged into RRE From 657,000 to 820,000 m?/d of wastewater are produced by the industrial area of Hanoi-Viettri-Haiphong The amount of 34 million cub.m Wastewater/yr
dumped into the Red River from the Viettri industrial site includes 100 ton H,SO,, 40 ton HCl, 300 ton benzene, and 25 ton pesticides An initial estimate shows that 6.535 ton heavy metals and 400 ton DDT pesticide are transported into the RRE every year by the river flow (Ninh et al., 1995),
Through agriculture, deforestation, industry and construction, the human activities have an adverse impact on ecosystems and biodiversity in the RRE, Many habitats have been destroyed, contaminated or otherwise harmed Biodiversity has decreased seriously, and rare and precious species are in danger Recently dramatic changes in the RR estuarine environment and ecosystems are obvious The changes have been caused both by natural processes and human
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Tuyển tập Tai nguyên uà Môi trường biển Tập X
change in supply and distribution of water, sediments, nutrients, and other materials into the sea: change in the quality of coastal and marine environment by the increased loading and accumulation of pollutants; and cause of the coastal habitat loss The emerging problems on environment of RRE are as follows
3.4.1 Increase in Natural and Technical Risks
Estuarine floods have increased in intensity and in frequency of occurrence This is the combined impact of upstream deforestation, heavy rains, sea-level rise, and the blocking of mouths by sedimentation Estuarine floods are especially severe and very dangerous when heavy rains and storm surges coincide during spring tides Red River Delta, which is known to be accreting, however, erosion has nevertheless occurred along one-fifth of ‘the coastline Especially, the Vanly coast of 30km long has been eroding at a rate of 10-15 m/year, during the last 50 years even though it is protected by dikes and embankments (Thanh, T.D et al., 1997) Sedimentation has become more extensive recently, with a particularly negative impact on the development of estuarine small harbors The longshore sand drifts generated by wave action block river mouths leading to coastal floods, and the loss of waterway to the sea Because of tidal pressures, saltwater now penetrates 30-50 km up the tributaries of Red River A combination of factors such as the decrease in river-water discharge caused by dams and irrigation and the sea-level rise may have led to
more saltwater intrusion, which is a serious problem not only for coastal
agriculture but for other sectors of the economy as well
8.4.2 Environmental Pollution
The estuarine environmental quality is still rather good; although varying levels of pollution have been recorded at some sites due to contaminants produced by human activities in watersheds or in estuarine and marine areas Oil pollution is the most serious The oil content usually exceeds the standard of 0.05 mg/l for fisheries and even the standard of 0.3 mg/l for domestic activities at some sites (Dieu, L.V., et al., 2000), Pollution caused by heavy metals such as Zn, Cu, Cd Hg, As Pb is not yet widespread, but the concentrations of these pollutants may be increasing in coastal waters sediments and wildlife Pollution from Zn, and Cu has been confirmed (Dieu, L.V et Hoa, 2001) and their influence on the beings has been assessed (Duc, N.X & T.X.Lam, 1999) Similarly, organic- matter pollution is distributed locally but is heavy at some sites In general, pesticide residues have been below standard limits in estuarine water, however, evidence for their accumulation is widespread in bottom sediments and they exceed standard limits in many sites Eutrophication and red tide are not a
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serious problem yet in RRE, however, they are a threat for the future development of intensive aquaculture Residues of ten organochlorinated pesticides such as HCB: Lindane; Aldrin; 2,4’ DDE: Dieldrin; 2,4’- DDD: Eldrin; 2.4- DDT and 4,4’: DDT have been found in estuarine water, sediments and creatures (Cu, N.D., 1999)
3.4.3 Loss of Habitat and Decreases in Living Resources
The recent natural and human-caused changes to RRE have led to the loss of such habitats as tidal flats, mangrove marshes, beaches and seagrass beds The mangroves have been heavily damaged by agriculture, aquaculture, and fire wood and even by erosion (Hong & San, 1993) The beaches have been narrowed by erosion and sand quarrying Seagrass beds have been destroyed by turbidity, freshening of the water, strong typhoon waves, and pollution RRE is a site of breeding and spawning grounds essential to the maintenance of fishery production The pollution and the loss of habitats have degraded living resources for coastal and offshore fisheries The estuarine changes in environment put the survival of many marine Species at risk (Ministry of Fishery, 1996) The degradation of estuarine ecosystems due to salt intrusion, turbidity, pollution, and loss of habitat leads to the disruption of the ecological balance and to decreases in biological productivity and biodiversity The marine fishery, which is mainly related to the estuarine ecosystems, faces a decrease in living resources due to environment degradation and over catching
1 GENERAL ASSESSMENT
4.1 Achievements
¢ To obtain principal data on the natural factors in RRE as follows:
- Climatology: season regulation, radiation, temperature, rainfall, wind,
typhoons and others
- River hydrology: water and sedimentary discharges, their distribution by space and seasons, and discharges of some nutrients such as nitrogen, phosphorus and silicon
- Marine hydrology: tidal regulation, wave, current, sea level change and storm surge, and some physical-chemical factors such as water temperature, salinity, pH and DO,
- Geomorphology and sediments: landforms and their origins, bottom and
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e To have the knowledge of estuarine processes consisting of sedimentary transportation and deposition, coastal accretion and erosion and displacement of river mouths
¢ To have the significant research results of estuarine ecosystem in term of its function community structure components of species and assessment on biodiversity, individual density and biomass A lot of rare and precious species have been listed in the Vietnam’s Red Book Especially, the research in mangrove ecosystem has achieved good results
© To have the reliable research data on nutrients and primary productivity
with the components of phytoplanktons seagrasses and mangroves The main nutrient factors such as phosphorus, nitrogen and dissolve silicon in estuarine water and phosphorus nitrogen and organic carbon in estuarine sediments have been researched and estimated in term of their content, distribution and change
with the tidal phase and season
¢ To have the basement knowledge of natural resources, including non-living and living ones and an orientation for suitable utilization of them RRE has a great potential of natural gas, lignite, peat and some construction materials Its accreted land yearly is precious for development of settlement angas agriculture
brackish aquaculture and salt making The high value of biodiversity and great
potential of natural conservation typical by Ramsar Site of Xuan Thuy have been confirmed The potential of estuarine fishery including brackish aquacultural objects and areas, and catching and gathering grounds has been determined
¢ To have an assessment on the status of estuarine environment with the emerging problems such as decrease of biodiversity and fishery production, damage of habitats, pollution, and environmental disasters concluded coastal erosion, flood and salt intrusion Sources of these impacts have been determined in the relation to the human activities in both catchment and in situ They are of
development of industry, domestic activities, use of chemical fertilizes and
pesticides, damming, irrigation, building system of sea and river dikes, destroying upstream forest and mangroves, over catching and over aquaculture
etc
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and analyze for environment of RRE have been working
¢ To have an approach to suitable use of ecosystem and sustainable
development of natural resources and environment of RRE The scientific results
have made contribution to making of policies, resolutions and technical patterns of eco-social development and protection of natural resources and environment of
RRE
4.2 Shortcoming
¢ There is a lack of integration in researches RRE is a natural entity / ecosystem and needs a systematic research data to manifests its nature There are many research projects on RRE or Red River Basin, however, the researched area of most them has not corresponded to the boundary of this estuary A small number of projects are detailed in content, but they are implemented only in a certain part of estuary A great number of projects have covered in a very large
area of coastal zone included RRE, but generally, they have researched separate
special subjects, for example intertidal zoobenthos, coastal erosion or fishery resources Very few projects are specialized in RRE as an entity For this reason, there is also a lack of an overall picture of research results uy, RRE and there are gaps of data and information on this estuary
¢ There is a lack of synchronization in researches The obtained data on REE are for different subjects and objectives, non-synchronous and interrupted
in research process That is why it is difficult to integrate them for the purpose of
detecting the changes in natural resources and environment of estuarine ecosystem and finding the causes of those changes
¢ The researches are not detailed enough Most implemented projects are elementary investigations, not detailed in content and specialized in separate components of estuarine ecosystem The existing researches give mainly, in
statistics and description of status, and they are limited in modeling application
for the interaction processes The researches of many important issues of estuary such as material flux, nutrients, secondary productivity and food chain etc are only preliminary results There are even still a lot of gaps of data and information in those researches
* Accuracy of data is limited Due to the lack of the common standards in
field survey and laboratory analysis, sometimes there are conflicts between research results and opinions on the accuracy of obtained data The result obtained randomly from non-detail observations and surveys is also a cause of this situation
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© Publication and exchange oƒ data ¡is limited Despite limitations, the
results of researches in RRE are significant However, publication and exchange
of data and information are limited of many, not only with foreign scientists, but
also with Vietnamese experts 4.3 Approach
e Tocarry out comprehensively and fully principal investigation
e To observe and monitor regularly the natural resources and environment
e To research detail nutrients, pollutants material fluxes and estuarine
processes
* To in research land-sea interaction in RRE including changes in river discharges of water, sediments, nutrients and contaminants
* To research integrated estuarine management and socio-economic
sustainable development including some issues as follows:
- Impact of human activities and climate change on the estuarine natural
resources and environment; '“ - Prevention of coastal pollution:
- Protection of coastal environment and natural resources; - Natural conservation;
- Mitigation of coastal disasters
5 CONCLUSION
Rich in natural resources and important for eco-social development of
Vietnam Red River Estuary (RRE) has been researched by a lot of domestic
institutions and international organizations The research projects on RRE are independent or belong to the national research programs, mainly the National Programs for Marine Research and National Programs for Environment Protection that are organized every five years Those research projects have achieved the significant results and provided the principal knowledge on natural factors and processes components of ecosystem, including the nutrients, natural yesources and environment in RRE They are useful for eco-social development and natural conservation, and serve as an important database for further researches However, due to the difficulties in implementation and partly
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awareness, the researches in RRE have some shortcomings such as lack of integration, synchronization and systematization, and limitations in detail level and accuracy On the other hand, there are gaps in the obtained data, which need to be published and exchanged more widely It is necessary to carry out a more
detailed, integrated and comprehensive research with focused on nutrients,
pollutants, material fluxes and estuarine processes the under impact of both human activities and climate changes Hopefully, the international cooperation will be an effective resolution to address the need,
6 ACKNOWLEDGEMENTS
This work was supported by the Natural Science Council of Vietnam The
author would like to express his sincere thanks to Professor Dang Ngoc Thanh,
for his suggestions and encouragement to complete this report Many thanks are sent to the colleagues at Haiphong Institute of Oceanology, Dr Nguyen Duc Cu, Dr Luu Van Dieu, Dr Dinh Van Huy and Ms Nguyen Thi Phuong Hoa, who provide precious data and information on Red River Estuary
REFERENCES
1 Bo, D., Cu, N.D., 1996
Research on Primary Production in Littoral Ecosystem of Red River Estuary
Marine Resources and Environment VoLIII Sci & Tech Pub House, Hanoi,
p.169-176
2 Cu, N.D., 1996
Change in Tidal Wetland in Red River Estuary Journal of Sciences of the Earth, No.4, Hanoi, p.368-377
3 Cu, N.D., 1999
Trang 19Tuyển tap Tai nguyên uà Môi trường biển Tập X
4, Cu, N.D., 2001
Nutrients in Red River Estuary Marine Resources and Environment Vol.VIII Sci & Tech Pub House Hanoi
5 Cach, N.V 1999
Biodiversity Conservation and Management in Ramsar Site, Xuanthuy District, Namdinh Province Proc On Management and Sustainable Use of Natural Resources and Environment in Coastal Wetlands Vietnam National University, p 119-123
6 Cuong, N.M.1997
Forest Mapping in Vietnam In: Remote Sensing for Tropical Ecosystem Management New York United Nations Published, p 47-59
7 Dam N.K., 1962
Government Role for the Land Reclamation in the Vietnam History J Historic Research, N° 39, Hanoi
8 Dieu, L.V., Luu, V.T & Trang, C.T 2000 -
Some Remarks on the Tendency of Marine Environment Quality Change in
Vietnam Marine Resources and Environment, Vol.VII, Sci &Tech Pub
House, Hanoi, p.125-134
9 Dieu, L.V , N.T Hoa, 2001
10
11
Estimating Pollutants from Landbase Source to Coastal Sea in the North
Vietnam and Proposing Management Resolution of Pollution Technical Report of Project Reserved at Haiphong Institute of Oceanology
Duce, N.X., T.X Lam, 1999
Preliminary Study and Assessment on Ecological Impact of Pollutant
Transported froiPTivers into Coastal Area of Vietnam Proc The 4” National Conference on Carine Science and Technology, Hanoi 12-13 Nov 1998, pp
1244-1248
HIO (Haiphong Institute of Oceanology), 1977
Survey of Bottom Topography and Sediments in Coastal sea of Haiphong- Nghetinh Area Technical Report Reserved at HIO
Trang 20Tuyển tập Tai nguyên va Méi trường biển Tập X 12 13 14 15 16 17 18 19 20 50 Hoi, N.C., 1995
Research in Suitable Utilization of Typical Coastal Ecosystems in Vietnam
Technical Report of Project Coded KT.03.11 Reserved at Haiphong Institute of Oceanology
Hong D.N and San H.T., 1993
Mangrove of Vietnam Published by ICNU p.1 - 173
Huy D.V., 1994
Some Main Features in Coastal Morphology of Modern Red River Delta In:
“Marine Resources and Environment”, Vol.II Sci & Tech Pub House, Hanoi, p.30 - 37,
Huy, D.V., N.H.Cu, 2000
Aspect of Coastal Dynamics in Red River Delta Technical Report Reserved at Haiphong Institute of Oceanology
Hung N.M., 1992
-
Coastal Wave Field and WWave Dynamics Fluency on the Stability of Coastal Areas Proc National Sem on Coastal Zone Res and Manag Hanoi Dec
1993, p 99 - 109,
Ministry of Fishery, 1996
Aquatic Resources in Vietnam Agriculture Pub House, Hanoi, p.1-616
MOSTE, 1999
Abstracts of Research Results of National Programmes and Projects on
Science and Technology from 1991-1995,
NEA\MOSTE, 1998
Administrative Management on Environment Protection Published by MOSTE, Hanoi, p.1-123
Ninh, P.V et all., 1992
Trang 2121 22 23 24 2ã 26 27 28 29 Tuyển tập Tòi nguyên uà Môi trường biển Tập X Ninh, P.V , 1995
Marine Pollution Generated from Rivers Technical Report of Project Coded
KT.03.07 Reserved at Institute of Mechanics (NCST),
Pho N.V., 1984
The Streams in Vietnam Sci & Tech Pub House, Hanoi, p.1 - 209
Sinh, N.N., T.T Chieu, D.H.Huynh, N.N.Mai, N.V.Pho, D.N.Thanh, T.H.Tinh, 1985
Vietnam on a Path of Principal Investigation Sci & Tec.Pub House Hanoi
p.1-171
Thanh, D.N., 1991
Overview on Achieved Results of National Programme for Marine Research — 48B (NPMR —48B) from 1986-1990 Published by National Centre for Natural Science and Technology, p.1-45
Thanh, D.N.,1998
Marine Research Activities in Vietnam The Gioi Publishers, Hanoi, p.1-36
Thanh, T.D et all.,1984
Role of Geomorpho-geological Factors for the Mangrove Development in the Coastal zone of North Vietnam Proc Sem on Mangrove Ecos, Hanoi, p 33-47
Thanh, T.D et all., 1991
Morphology, Structure and Evolution of the Tidal Marshes in the Coastal Zone of North Vietnam Proc 3" National Conf on Marine Science, Hanoi, p 278 - 281
Thanh, T.D., Huy D.V., Lan T.D., 1996
Development of the Tidal Flood Plain in Red River Delta J Sciences of the
Earth N°.3 (18), Hanoi, p 50 - 59
Thanh, T.D, T.D.Lan and D.V.Huy, 1997
Trang 22Tuyén tap Tai nguyén va M6i trường biển Táp X 30 31 32 33 34, 35 36 37 38 Thanh, T.D., 2001
Influences of Reservoirs in the Catchment on the Environment of Estuaries and Coastal Seas Journal of Scientific Activities, No.11, Hanoi, p 13-15
Thanh, T.D., Huy, D.V., Nguyen, V.L., Ta,T.K.O., Tateishi, M., & Saito, Y 2001
The Impact of Human Activities on the Vietnamese Rivers and Coast Proc Asia BASINS I Workshop IGBP/LOICZ, Hongkong Baptist University,
China, 12 Dec — 14 Dec 2000 p.1-11, Thu, N.T., 1996
Zooplankton of Tienyen, Bachdang and Red River Mouths Marines Resources and Environment Vol III Sci & Tech Pub House, Hanoi, p 271-278
Thuoc, C.V., 1996
The Phytoplankton of Tienyen, Bachdang and Red River Mouths Marine Resources and Environment, VolIII Sci & Tech Pub, House, Hanoi, p.233-
342
>
Thuy, N.N., 1984,
Tide in the Vietnam Sea Sci & Tech Pub House, Hanoi p 1 - 263
Thuy, N.N and Khuoc, B.D.1994
El - Nino Phenomenon, Global Climate Warming, and Sea Level in Vietnam Sea and South China Sea J: Meteorology and Hydrology, No.5, Hanoi, p 16-23
Tiep, N.T., 1993
Coastal Morphodynamics of Red River Delta (Holocene - Modern) Doctoral Report in Geology - Geography Hanoi University
Trong, P.D., 1999
Some Characteristics of Species Composition, Distribution and Ecology of
Zoobenthos on Mangrove Area in the North Vietnam Proc The 4‘" National Conference on Marine Science and Technology Hanoi 12-13 Nov 1998, p.1039-1046
VCST (Vietnamese - Chinese Survey Team), 1965
Trang 23Tuyển tập Tài nguyên uà Môi trường biển Tập X 39 World Bank, 1996
Vietnam Water Resources Sector Review Selected Working Papers Published by World Bank
40 Yen, M.D., 1995
Impact of Human Activities on Aquatic Biodiversity in the Red River Delta Proc National Workshop on Environment and Aquaculture Development Haiphong, 17-19 May 1994, p.460-462
TOM TAT
TONG QUAN VE HOAT DONG VA KẾT QUÁ NGHIÊN CỨU MÔI TRƯỜNG
VÀ HỆ SINH THÁI VÙNG CỬA SÔNG HỒNG
Trần Đúc Thạnh
Do tài nguyên thiên nhiên phong phú và là khu vực quan trọng đối vó¿phát triển kinh tế - xã hội của cả nước, vùng cửa sông Hồng đã được nhiều cơ quan trong nước và một số tổ chức Quốc tế quan tâm nghiên cứu về mặt tài nguyên, môi trường và hệ sinh thái Các nghiên cứu liên quan đến khu vực này thuộc các các đề tài, dự án độc lập, hoặc thuộc các chương trình nghiên cứu Quốc gia, chủ yếu là các chương trình Nghiên cứu Biển và các chương trình Bảo vệ Môi trường được tổ chức theo kế hoạch 5 năm Các đề tài, dự án nghiên cứu này đã đạt được những kết quả có ý nghĩa và cung cấp những hiểu biết cơ bản về các yếu tố và các quá trình tự nhiên, các hợp phần của hệ sinh thái, bao gồm cả dinh dưỡng, tài nguyên và hiện trạng môi trường vùng cửa sông Tài liệu có được đã giúp cho phát triển kinh tế — xã hội, bảo ton ty nhiên và còn là cơ sở rất quan trọng cho những nghiên cứu tiếp theo Tuy nhiên, do khó khăn về điều kiện thực hiện và phần nào do nhận thức, hoạt động nghiên cứu vùng cửa sông Hồng còn thiếu tính tống thể, chưa đồng bộ và chưa hệ thống, còn hạn chế về mức độ chỉ tiết và chính xác Mặt khác, vẫn côn những khoảng trống tai liệu và những tài liệu này cần được công bố và trao đổi rộng rãi hơn Rất cần tiến hành nghiên cứu chỉ tiết, tổng thể, toàn diện hơn và chú trọng các vấn để dinh dưỡng, chất gây ô nhiễm, dòng vật chất và các quá trình cửa sông dưới tác động của con người và biến đổi khí hậu Hợp táo Quốc tế cũng sẽ là một giải pháp hữu hiệu để dap ứng yêu cầu này