VULNERABILITY ASSESSMENT OF VIETNAMESE COASTAL BAYS AND GULFS FOR SUSTAINABLE USE PLANNING OF ENVIRONMENT AND NATURAL RESOURCES: A CASE STUDY IN
THE TIÊN YÊN - HÀ CỐI GULF (
MAI TRỌNG NHUẬN1, NGUYỄN THỊ MINH NGỌC1, ĐỖ THÙY LINH1,
NGUYỄN THỊ HỒNG HUẾ1, TRẦN ĐĂNG QUY1, PHẠM BẢO NGỌC1, QUÁCH ĐỨC TÍN2
Hà Nội University of Science, 334 Nguyễn Trăi Str., Hà Nội
2Việt Nam Institute of Geosciences and Mineral Resources, Km 9, Nguyễn Trăi Str., Hà Nội
Abstract: The vulnerability of
natural resources and environment of the Tiên Yên - Hà Cối Gulf, the
greatest one in the gulf system in Việt
The Vietnamese country has about 40 gulfs and
bays with the total area of 4,481 km2, among them, the Tiên Yên - Hà
Cối Gulf , located in the northeast of Quảng Ninh Province, is the
biggest one (560 km2, Fig. 1). This gulf has diverse natural
resources, including placer mineral deposits, 13 wetland types, underground and
surface waters. This gulf is also an important area in North Việt
Currently, natural resources and environment of the Tiên Yên - Hà Cối Gulf are being extensively exploited and used for several purposes, such as aquaculture, fishing, harbour activities (for example, Vạn Hoa and Mũi Chùa harbours), water transport, industria-lization and urbanization (for example, seaward extension and wetland reclamation by VINASHIN Corporation), exploitation of placer minerals, tourism, etc.. Together with the abundance of natural hazards around the gulf (for example, erosion, deposition, landslide, flood, storm, and earthquake), the unsuitable exploitation of natural resources and environment can be recognized as main factors, leading to negative changes, such as: decrease of land area due to erosion, decrease of mangrove forest area on the contrary of increasing man-made wetland area for aquaculture (for example, pond and cage aquaculture), depletion of aquatic resources and degradation of habitats. Besides, the gulf environment has high risk of pollution by heavy metals, oil and PCBs in water and sediment, as the results of industrialization, urbanization and development of harbours and sea transport.
Figure 1. Location of the studied area - the Tiên Yên - Hà Cối Gulf
In order to plan sustainable natural resource
and environment use, many countries in the world have been approaching the
vulnerability assessment of the nature-society system in such areas where
natural resources and environment are being under stress from hazards and human
activities. This paper presents the results of the vulnerability assessment,
which is in first time applied for gulf system of Việt
II. METHODOLOGY OF ASSESSING THE VULNERABILITY OF NATURAL RESOURCES AND ENVIRONMENT
The methodology of assessing the vulnerability of natural resources and environment applied in this work is inherited from methods and criteria for assessment of coastal vulnerability index (CVIs) of America [1, 10], environmental vulnerability index (EVI) of SOPAC , assessment protocol of NOAA  with adjustment to the actual situation of Việt Nam [3, 4, 6, 10]. The assessment criteria are weighed up according to the Assessment Matrix method of Thomas Saaty [8, 9] based on the Expert Choice software, then graded and grade-based ranked (from 1 for the lowest level to 5 for the highest level) for dangers by the level of risks (or pressures) (i.e. hazards and potential factors causing or intensifying hazards), density and coping capacity of vulnerable objects. The protocol of establishing vulnerability map of natural resources and environment in Tiên Yên - Hà Cối Gulf is presented in Figures 2.
Figure 2. Protocol of establishing the Vulnerability map of natural resources and environment in the Tiên Yên - Hà Cối Gulf in GIS.
III. CRITERIA OF ASSESSING THE VULNERABILITY OF NATURAL RESOUR-CES AND ENVIRONMENT IN THE TIÊN YÊN - HÀ CỐI GULF
1. Factors causing vulnerability and the level of risk
The factors causing vulnerability in the Tiên Yên - Hà Cối Gulf can be determined as of including 2 main groups: 1) Hazards (erosion, channel deposition, landslide, storm and flood, earthquake, environment pollution by heavy metals and organic compounds, etc.) (Table 1); and 2) Factors intensifying hazard, among them natural factors consist of tectonic fault systems, geological background with different cohesion level or different pollutant retent, etc., and man-made factors with human activities, such as aquaculture, mangrove destroying, agriculture, industry, etc..
Risk from factors causing vulnerability is assessed on the basis of the nature of hazards, following the formula proposed by Cutter : G = (F + A) × M (in which, G: total grade of the hazard, F: hazard frequency and M: hazard intensity) and characteristics of hazard intensifying factors. These two criteria classes are classified and interpolated for every 4 km2 of cell in a map by mathematic algorithms in GIS like classification, ranking, determination of density and distance, etc. After grading, the processed data are overlapped based on algebraic weighed mapping methods to create the map of risk at 1:50.000 scale (Fig. 3). The total grade of every cell in the map is the basis of dividing the studied area into 4 zones with risk from low to high levels as follows:
a. Zone of low risk: accounting for the greatest area, of 44.9 % of total area of the gulf, including mainland communes of Đại Đức, Quảng An, Quảng Lâm, Quảng Sơn, Đại Xuyên and offshore areas. This zone lies under low impacts of earthquake, flood and regardless influences from other hazards, whereas human activities are not intensive.
b. Zone of medium risk: accounting for 35.2 %
of total area of
the gulf, including the inland around upstream of
Figure 3. Map of risk in the Tiên Yên - Hà Cối Gulf
Figure 5. Map of coping capacity in the Tiên Yên - Hà Cối Gulf.
Figure 6. Map
of natural resources and environment vulnerability
of the Tiên Yên - Hà Cối Gulf at 1:50,000 scale.
c. Zone of high risk: accounting
for a small area, of 13.1% of total area of the gulf, including a narrow track
around the zone of medium risk, a narrow track along the coast,
d. Zone of extremely high risk: accounting for 6.8 % of total area of the gulf, including coastal land and catchment-area of rivers, such as Đầm Hà, Hà Cối, Ba Chẽ and Tiên Yên ones, towns, such as Hà Cối, Tiên Yên, coastal communes, such as Quảng Minh, Phú Hải, Quảng Điền, Quảng Phong, Tiến Tới, Tân B́nh, Đại B́nh, Đông Hải and the coastal sea of 0-6 m water depth. This is the lowland under extremely high influence of many hazards (channel deposition, coastal flood, erosion, environment pollution by oil and heavy metals). This zone has also high concentration of human activities, especially factories, intrustrial quarters, mining, aquaculture, fishing, harbours and sea transport.
2. Density of vulnerable objects
When hazards happen, vulnerable objects in the Tiên Yên - Hà Cối Gulf can be determined as including residential areas, infrastructures, natural resources and environment. The major residential areas include cities, towns, and coastal villages and communes, such as Tiên Yên, Đầm Hà, Quảng Hạ ..., where high population is concentrated. The infrastructure includes railways, highways, harbours, ports, bridges, dikes, dams, factories, industrial quarters, Khe Xong hydroelectric factory, aqua-product processing enterprises, coal mining enterprises, etc., schools, hospitals, cultural constructions and touristic places (Mũi Chùa harbour, Tiên Yên old streets, Hải Hà economic zone, Quảng Điền industrial-urban zone), etc..
Natural resources include mineral mines, landscapes, wetlands, bio-resources and ecosystems. Mineral resources of the Tiên Yên - Hà Cối Gulf include placer titan-zircon - rare earth mines and occurrences of ilmenite, zircon, rutile, anatase, cassiterite, corundum and gold of small reserves. Wetlands in the Tiên Yên - Hà Cối Gulf is diverse with 13 coastal types (according to the Wetland Classification System, proposed by VEPA, 2007), including: permanent shallow marine water <6 m of depth at low tide (Aa), gulfs and bays (Ab), estuaries (F), submerged estuarine sandy islets (Fa), estuarine barrier islands (Fb), rocky marine shores (D), beaches (Ea), intertidal shingle or pebble shores (Eb), intertidal muddy sand shores (Ga), intertidal sandy mud shores (Gb), mangrove forests (I), salty/ brackish aquaculture ponds (1a) and sedge farms (10). Biodiversity is rather high with 754 species and several ecosystems, such as mangrove forest ecosystem (3,000 ha), sea grass ecosystem (230 ha), intertidal ecosystem (>18,000 ha), benthos ecosystem (accounts for 2/3 total area of the gulf).
Similarly to the risk from vulnerability causing factors, the density of vulnerable objects can be determined based on features, such as distribution, functions and socio-economic and environmental values of the objects, which may be influenced by the mentioned hazards and hazard intensifying factors. Among these objects, the highly graded vulnerable ones are: human (i.e. population, education level, public health care, etc.), coastal hazard mitigation constructions (i.e. dike, sea wall, dam, etc.) and natural resources with high economic values or functions of environmental protection and hazard mitigation (i.e. geosite, geotope, wetlands, etc.). The integrated grade in every cell of the map reflects the density of vulnerable objects in this place. Based on differentiation in the vulnerable object density map of the studied area, four different zones with distinctive vulnerable object density can be defined as follows:
a. Zone of low vulnerable object density: occupying the largest scale in the total area of Tiên Yên - Hà Cối Gulf (of about 49.3 % of the total area), distributed around the highland of Đại Đức, Quảng An, Quảng Lâm, Quảng Sơn, Đại Xuyên communes and on offshore of the gulf. This zone is characterized by low density of inhabitants, construction and low economic values or functions of resources and ecosystems.
b. Zone of medium vulnerable object density: occupying about 29.1 % of the total area of the gulf, including almost all areas surrounding mountains of the Quảng Long, Động Ngư Communes and highlands of Đại Xuyên, Văn Yên. This zone is characterized by the medium density of vulnerable objects, medium education level and public health care and unintensive exploitation of natural resources (i.e. geosites, wetlands, etc.).
c. Zone of high vulnerable object density: occupying about 14.5 %, distributed in a narrow band along the catchment-area of Đầm Hà, Hà Cối, Ba Chẽ, Tiên Yên Rivers and the Cái Bầu, Sầu Đông, Sầu Nam, Chương Ca, Đá Dừng, Gà Đua, Thạch and Cẩm Thạch Islands, next to zone of medium vulnerable object density. This zone has high potential for development of communication and transport, tourism, mineral exploitation and aquaculture. The intellectual level and infrastructure are quite developed.
d. Zone of extremely high vulnerable object density: occupying small area (about 7.1 % of the total area of the gulf), distributed in cities, towns and catchment areas of rivers (Đầm Hà, Hà Cối, Ba Chẽ, Tiên Yên). Highly concentrated in this zone are inhabitants, construction and natural resources of high values and functions. Wetland resources include several types, such as aquacultural ponds, estuaries, mangrove forest. Industrial zones, great harbours and sea ports in this zone have also high significance for socio-economic development.
3. Coping capacity of the natural resources and environment
Coping capacity of natural resources and environment of the Tiên Yên - Hà Cối Gulf includes objects with natural coping capacity (i.e. mangrove forest, river systems, estuaries, intertidal flats) or with social coping capacity (i.e. intellectual level, actions aiming to conserve natural resources and to protect the environment, education and propaganda aiming to raise the community awareness on hazard mitigation and protection of environment, natural resources and infrastructures,…).
Based on values and functions of mitigating vulnerability causing factors and capacity of conserving natural resources and protecting the environment, the above determined objects can be graded on coping capacity, interpolated for every 4 km2 cell, and then overlapped by weighed map algebra. By the establishment of coping capacity map of natural resources and environment in the Tiên Yên - Hà Cối Gulf at 1:50,000 scale (Fig. 5), five zones can be distinguished according to their coping capacity:
c. Zone of low coping capacity: occupying 16.9 % of
the total gulf area, distributed in the southeast and northwest of
d. Zone of medium coping capacity: occupying 63.9 % of the total gulf area, distributed in the east of Sầu Nam island, east of Thoi Xanh island and the highlands of communes, such as Quảng Sơn, Quảng Lâm, Quảng An, Dương Ḥa, Đại Đức, Đại Xuyên, Văn Yên, etc.. In these areas, residences are scattered with low to medium levels of intellect, education and socio-economic development, whereas the natural resources, such as geosites, geotopes and wetlands, are not so abundant.
e. Zone of high coping capacity: occupying 10.3 % of
the total gulf area, distributed along a narrow band in the
catchment-areas of the Đầm Hà, Hà Cối, Ba Chẽ and
f. Zone of very high coping capacity: occupying 8.9 % of the total gulf area, including concentration areas of objects of high natural coping capacity (i.e. mangrove ecosystem) and social coping capacity (high intellectual level, developed infrastructure, suitable management and protection of natural resources and environment), such as catchment-areas of rivers, cities, towns (Đầm Hà, Hà Cối, Ba Chẽ, Tiên Yên), and communes (Tiên Lăng, Đại B́nh, Đầm Hà, Tân B́nh, Quảng Phong, Quảng Điền and Phú Hải).
IV. ASSESSMENT OF VULNERABILITY OF NATURAL RESOURCES AND ENVI-RONMENT IN THE TIÊN YÊN - HÀ CỐI GULF
The overlap by weighed map algebra (Fig. 2) of the determined three criteria classes is as follows: 1) Risk from vulnerability causing factors; 2) Density of vulnerable objects; and 3) Coping capacity of natural resources and environment allowing the establishment of the vulnerability map of natural resources and environment in the Tiên Yên - Hà Cối Gulf (Fig. 6) at the 1:50,000 scale. In this map, 4 distinctive zones of vulnerability levels from low to high can be distinguished as follows:
a. Zone of low vulnerability: occupying 51.3 % of the total gulf area distributed in the offshore and highland areas in the Đại Dục, Quảng An, Quảng Lâm, Quảng Sơn communes. These areas suffer insignificant influence from hazards (earthquake and flood happening in very low intensity) and stress from socio-economic development, not abundant in natural resources (including construction materials, agricultural land in small areas and some aquaproducts) and medium coping capacity (without mangrove ecosystem, medium hazard resistance).
b. Zone of medium vulnerability: occupying 28% of the total gulf area, distributed next to the zone of low vulnerability and including the offspring areas of the Tiên Yên, Ba Chẽ, and Đầm Hà Rivers (in the Quảng Thanh, Dương Ḥa, Dục Yên, Đông Ngư and Tiên Lăng Communes), Đại Xuyên and Văn Yên Communes. These areas have medium risk for vulnerability causing factors (except for potential of Pb pollution in sea water of some local areas), medium density of residence and other vulnerable objects, whereas human activities are mostly agriculture, aquaculture and undeveloped services and trade.
c. Zone of high vulnerability: occupying 13.3 % of the total gulf area, distributed mainly in the Đồng Ngư, Đồng Lâm, Tiến Tới, Tiên Lăng, Đồng Rui, Quảng Long, etc. communes and system of small islands (Tràm, Treo, My, Keo, Đầu Gỗ, Sú Mọt, etc.). This zone has high residential density, with typical human activities, such as aquaculture, fishing and ecotourism. The area of mangrove forest is small, whereas sediments are mainly composed of sandy mud and muddy sand with medium to high potential of trapping pollutants. Hazards in this zone include landslide, earth crack, channel deposition at estuaries, bedding erosion (in the Tiên Yên estuary and Đại estuary), Pb pollution of sea water.
d. Zone of extremely high vulnera-bility: occupying 7.3 % of
the total gulf area, including the catchment-areas of the Tiên Yên, Ba Chẽ and Đầm Hà Rivers; the Hà Cối and Tiên Yên Townlets; the Quảng Hạ, Quảng
Trung, Quảng Điền, Quảng Phong, Tiến Tới,
Tân B́nh, Đại B́nh, etc. coastal communes, and coastal sea from 0-5 to 7 m of water depth. This zone has high residential density with intensive
activities of industry, tourism, aquaculture and procession of aquaproducts,
sea transport and mining. This zone suffers the influences of several hazards,
such as channel deposition (Ba Chẽ estuary, Tiên Yên estuary), erosion (Đầm Hà - Tiên Yên) and flood in coastal lowlands. In addition, the presence
of submarine rock peaks along the Ba Chẽ and
Table 2. Actions for sustainable use of natural resources and environment in the Tiên Yên - Hà Cối Gulf , based on vulnerability assessment
V. RECOMMENDATION FOR SUSTAI-NABLE USE OF NATURAL RESOURCES AND ENVIRONMENT BASED ON VULNERABILITY ASSESSMENT
The assessment of the vulnerability of natural resources and environment in the Tiên Yên - Hà Cối Gulf shows that areas of high vulnerability is generally characterized by combination between high risk (from hazards and intensifying factors), medium to high density of residence, infrastructure and natural resources, whereas the coping capacity of socio-economic system is just medium.
In the contrary, the areas of low vulnerability not only have low risk from hazards, but also are located far from social or economic centres, residential zones or position of high function-value resources. Therefore, the planning for sustainable use of natural resources and environment should involve in zoning based on vulnerability. The planning of suitable solutions for mitigation of hazards and human activities intensifying hazards, redistribution of vulnerable objects and strengthening coping capacity of socio-economic system should be proposed and implemented for each corresponding zone. Table 2 shows the planning solutions proposed for the Tiên Yên - Hà Cối Gulf.
Furthermore, it is necessary to implement synchronic solution for sustainable use of natural resources and environment in the Tiên Yên - Hà Cối Gulf, including suggestion of manage-ment measures (enforcement of laws and policies, community based management, integrated coastal zone management), mitigation of coastal hazards (recovery of mangrove area in Đồng Rui Commune) strengthening constructions protecting the coast (dyke, dams, water-break, etc.) and resistance against erosion in Mũi Chùa, Vạn Hoa Ports and Tiêu estuary), application of science and technologies (investment for research and development of ecological economic models, such as eco-aquaculture, ecotourism, sustainable mining, green technology, etc., construction of natural resources and environment monitoring).
1. The factors determining the vulnerability of natural resources and environment of the Tiên Yên - Hà Cối Gulf are vulnerability causing factors (with hazards, such as erosion, channel deposition, storm and flood, pollution of water and sediments, etc. and hazard intensifying activities, such as aquaculture, agriculture and tourism), density of vulnerable objects (i.e. natural resources, environment, residences and infrastructure) and coping capacity (including objects with natural coping capacity, such as mangrove forest, intertidal muddy sand or sandy mud flats, consolidated geological formations, or with social coping capacity, such as intellectual level, infrastructure and programs, actions protecting natural resources and environment, mitigating hazards, etc.).
2. The Vulnerability Map of natural resources and environment of the Tiên Yên - Hà Cối Gulf at 1:50,000 scale has been established based on weighed map algebra with overlapping of three criteria classes: risk from vulnerability causing factors, density of vulnerable objects, and coping capacity of natural resources and environment.
3. Based on vulnerability assessment, the studied area has been divided into 4 zones with from low to high vulnerability levels. The zone of high vulnerability is generally under influences of many hazards and hazard intensifying factors, high density of residences and high function-value resources, such as mangrove forest, placer minerals, geosites, etc., whereas awareness on risk of hazards, leading to inadequate management and protection of natural resources and environment (catchment-areas of the Tiên Yên, Ba Chẽ, and Đầm Hà Rivers; Hà Cối and Tiên Yên Townlets; and Quảng Hạ, Quảng Trung, Quảng Điền coastal communes, etc.). The zone of low vulnerability is generally under low risk from hazards, far from socio-economic and industrial centres, whereas wetlands and bio-resources are not diverse and abundant (offshore areas and mainland areas in Đại Dục, Quảng An, Quảng Lâm and Quảng Sơn Communes).
4. Based on the vulnerability assessment, solutions for sustainable use of natural resources and environment of the Tiên Yên - Hà Cối Gulf have been proposed in correspondence to each zone of low, medium, or high vulnerability different works, such as: planning and application of socio-economic models (i.e. community based forestation, ecotourism, eco-aquaculture, sustainable mining, sustainable water communication and transport, eco-agriculture), hazard mitigation and strengthening the coping capacity of natural resources, environ-ment and community (management of natural resources and environment, education to raise community awareness, environmental monitoring, etc.).
Acknowledgments: This paper is completed with the support from the Project of Basic Research under the code 704006.
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