Status of Ecological and Geological Environment and Protection and Development in Quanzhou Bay Area

Liu Bailing

(Geological Engineering Survey Institute of Fujian Province, Fuzhou 350002)

Abstract: Based on the review of the current status of the ecological and geological environment of the Quanzhou Bay area, the hazards of various ecological and geological environmental problems are discussed, the main factors of their formation are analyzed, and the development trend is predicted, and then countermeasures are proposed for the protection and rational development.

Keywords: Quanzhou Bay; ecological and geological environment; biological resources; development trend; protection and development

Quanzhou Bay is located in southeastern Fujian, at the confluence of the Jinjiang River and the Luoyang River at the mouth of the sea, and it is a drowning-valley harbor. The harbor is surrounded by Quanzhou City, Jinjiang City, Shishi City and Hui'an County, and the regional economy is relatively developed. To find out the history and current situation of the ecological environment and geological environment of Quanzhou Bay area, combined with urban and rural socio-economic development planning, to predict the evolution trend of the ecological environment and geological conditions in the region, for the construction of ecological harbor and the sustainable development of the surrounding areas of the socio-economy is of great significance.

1 Socio-economic conditions

Quanzhou Bay surrounding areas of human engineering, economic activities are extremely strong, the distribution of the bay around the city of Quanzhou, Jinjiang City, Shishi City, and other emerging industrial cities, for the "Golden Triangle of Southern Fujian Economic Development Zone" part of the gradual development of the "big", "Quanzhou - half an hour city cluster," and gradually developed into the "big". Quanzhou - half-hour city cluster". According to the relevant information, the strategic positioning of Quanzhou City is "a port city of industry, trade and tourism". Its development goal is that by 2005, the level of urbanization will reach 43%, and the city will become affluent; by 2010, the level of urbanization will reach 50%, and the per capita GDP will reach 5,000 US dollars, and the city will be basically modernized.

2 Geological and environmental conditions

Quanzhou Bay is a drowned-valley type bay, and its surrounding geomorphology is mainly sedimentary plains and laterite terraces, and the coasts are mostly earthy and muddy, and there are many flood and tide protection projects. Most of the elevation of Quanzhou Plain is 3-5 m. The stratum of the bay area is mainly the Holocene and Pleistocene strata of the Quaternary System, and the lithological characteristics are as follows:

(1) Alluvial layer of Changle Formation of the Holocene System of the Quaternary System (Q4cal), and the lithology mainly consists of clay and medium-coarse sand.

(2) Quaternary Holocene Changle Formation marine deposit (Q4cm), the lithology is mainly silt and silty soil.

(3) Quaternary Pleistocene Longhai Formation alluvium (Q3lal), lithology is mainly clay, medium-coarse sand, mud-bearing gravel pebbles and so on.

(4) Quaternary Pleistocene (undivided) Residual Slope Accumulation Layer , the lithology is residual slope clay, sandy (gravelly) clayey soil.

The area is mainly passed by the north-east oriented Changle-Zhaoan fracture zone and the north-west oriented Yong'an-Jinjiang fracture zone, which are active fractures, and the earthquakes occurred around Quanzhou Bay many times, which are closely related to the above active fractures.

3 Eco-environmental and geological conditions

3.1 Siltation in the Bay

3.1.1 Siltation history and current situation

During the period of the Song and Yuan Dynasties, Quanzhou Harbor was one of the world's "Four Great Harbors", and was the starting point of the "Maritime Silk Road". The starting point of the "Maritime Silk Road". At that time, Quanzhou Bay was a deep-water harbor. Later, as human engineering and economic activities gradually increased, soil erosion phenomenon increased, coupled with the role of other natural factors, Quanzhou Bay gradually appeared silt phenomenon.

Since the 1960s, the siltation of Quanzhou Bay is more significant. 1970s not to the early 21st century, the Jinjiang River to the sea outlet of the river bed to the Jinji sluice section, the average annual silt height of about 0.2 m. So far, the river bed has been an average of silt height of 4 to 5 m. Now the river can only be navigable by the tide at high tide level. At the mouth of the Luoyang River in the original Houzhu harbor area, the 1996 remote sensing interpretation and the topographic map of the 1970s compared, the original 10m isobath has disappeared, now 2m isobath instead of the original 5m isobath location, zero-meter line to the main channel extends nearly 20m per year, silt high speed rate of about 6cm / a, the original Houzhu harbor has been scrapped. The new Houzhu harbor is also only able to rely on dredging to maintain the operation, on the verge of being scrapped; according to the 1998 remote sensing interpretation and recent measurements, ark river - head of the river channel large tidal flats have been linked together (Fig. 1); Baiqi Ferry west of the tidal flats, silt height of about 2 to 3m over the past 30 years, silt high speed rate of 10cm/a, silt to the center of the river is about 100m, silt width rate of about 3-4m/a, the siltation area of about 11 to 3m, the silt width rate of about 3-4m/a, and the silt depth of about 1m. The siltation area is 11.7km2, and the siltation trend is extremely significant.

Figure 1 Distribution of tidal flats in Ark River-Shuitou River Channel

3.1.2 Main hazards of siltation in the bay

The more serious siltation in Quanzhou Bay restricts the development of Quanzhou Port, which directly affects Quanzhou City's strategic positioning of "a port city for industry, trade, and tourism".

3.1.3 The main factors of siltation in the Bay

(1) The more serious erosion in the Jinjiang River Basin and Luoyang River Basin is the most important factor leading to the more serious siltation in Quanzhou Bay.

Quanzhou City, Jinjiang River Basin, soil erosion historical changes are shown in Figure 2, as can be seen from the figure, before the mid-1990s, soil erosion area was rising year by year, when it is also the most serious period of siltation, the mid-1990s to the present, although the area of soil erosion has been reduced year by year, but the absolute loss of area is still very large, although the upstream siltation of the source of the reduction of the relative amount of the still larger, siltation will continue, only its rate is relatively reduced.

Figure 2 Changes in soil erosion in Jinjiang River Basin, Quanzhou City

(2) Large-scale land enclosure is also another major factor in the serious siltation. The main enclosure projects in the area, such as "Wuyi Reclamation", "Chengdong Reclamation" and other tide protection projects (Fig. 1), have reduced the tidal area of Quanzhou Bay by nearly 1:3. The amount of tidal flow has decreased drastically, and the hydrodynamic conditions have been altered, which has weakened the scouring capacity of Quanzhou Bay and increased the corresponding siltation, thus contributing to the serious siltation. The corresponding siltation is enhanced, thus promoting the siltation of Quanzhou Bay.

(3) the construction of water storage, water stopping projects: such as the construction of reservoirs, sluice gates (Jinji sluice gates, Luoyang sluice gates), so that the upper reaches of the incoming water to reduce the siltation is another factor.

Because of the reduction in the amount of water coming from the upper reaches of the river, thus making the river on the Quanzhou Bay siltation ability to reduce, and the reduction in the amount of water also led to the slowing down of the water flow rate. According to the relationship between the sand-carrying capacity of the water flow and each element of the equation:

ρ0=K′×Vm3/(g×R×ω)

In the formula: ρ0 - sand-carrying capacity of the water flow (kg/m3);

Vm - average flow velocity of the water flow section (g×R×ω). - average velocity of water flow section (m/s)

R - hydraulic radius of over-water section (m);

ω - average sedimentation velocity of suspended sediment (m/s);

K′ - coefficient determined by the measured data (kg/m3)

The above formula shows that the sand holding capacity of the water flow is proportional to the cube of the water flow rate. With the slowing down of the water flow, the sand holding capacity is sharply reduced, so that the suspended particulate matter precipitation and siltation. At the same time the upstream freshwater to reduce the amount of salt current upstream, salt and freshwater junction zone to the upstream direction migration, due to siltation in the salt and freshwater junction of the condensation method, resulting in siltation area is also upstream, exacerbated by the Jinjiang River, Luoyang River estuary channel siltation.

(4) the relative decline in sea level: Quanzhou Bay recently (1972 ~ 1980) crustal vertical rise rate of about 4mm / a, while the absolute rate of rise in sea level over the same period of about 3.4mm / a, the relative rate of decline in sea level of about 0.6mm / a, the relative decline in sea level will inevitably lead to the sea depth becomes shallow, the corresponding tidal flats elevated, the Gulf of the relative siltation of the protruding.

3.2 Water environment

3.2.1 The history and current status of the water environment

Quanzhou Bay's history records, the old days of Quanzhou Bay for the water is clear and fish jumping, suggesting that there was less pollution of the water environment, the water environment is of high quality. However, with the enhancement of human economic activities around Quanzhou Bay, the water environment has also been affected. Quanzhou Bay 1985 to 1988 and 1996 to 1999 seawater quality analysis and testing of the main items of the average index list 1. Table shows that the water quality of Quanzhou Bay in the mid-1980s to the mid- to late-1990s, especially in the mid- to late-1990s, the water quality deteriorated markedly, varying degrees of pollution, the content of various hazardous substances there is a clear upward trend in the bay waters are subject to environmental pollution, the phenomenon of environmental pollution is becoming increasingly serious, the sea area is also affected by environmental pollution. The phenomenon of environmental pollution of the Gulf waters is becoming more and more serious, and the environmental quality of the sea area is on a downward trend.

Table 1 Comparison table of water quality analysis in Quanzhou Bay area

3.2.2 Impact of the water environment

Since Quanzhou Bay is the main harbor of Quanzhou City, and one of the important aquaculture areas in the province, the decline in the quality of the water environment and the increase of various pollutants, and the environmental capacity will cause disastrous consequences. The main effects are: (1) red tide phenomenon in the sea area, the survival of the sea is threatened. (2) the decline in the quality of the water environment, especially the cumulative pollution of the estuarine area [1], directly affecting the development of marine aquaculture, seawater, mercury, lead and other harmful heavy metals are beyond the standards of the aquaculture functional zone, resulting in degradation of aquaculture functions, endangering marine aquaculture, affecting the development of the marine economy of Quanzhou City. (3) cause coastal pollution, which in turn affects the survival of coastal organisms and destroys the ecological environment.

3.2.3 Main factors affecting the water environment

(1) With the development of the national economy in the surrounding areas, the production of domestic wastewater increases year by year (Figure 3), most of which is incorporated into Quanzhou Bay, which further contributes to the decline in the quality of the water environment.

Figure 3 Wastewater Discharge Map

(2) Large-scale engineering and economic construction in the neighboring areas, which produces wastes that are directly discharged into Quanzhou Bay, also affects the water environment.

(3) Reclamation and land reclamation have reduced the amount of tidal flow in Quanzhou Bay, which has weakened the dilution and diffusion capacity of pollutants, resulting in the aggregation of pollutants.

(4) unscientific and irrational breeding in the sea area, such as high-density breeding feed put residue, etc., are affecting the quality of the water environment.

3.3 Biological resources

3.3.1 Status of biological resources

Quanzhou Bay region has favorable geographical conditions, pleasant climate, to provide good environmental conditions for the survival and development of biological resources, Quanzhou Bay is rich in existing biological populations, according to the relevant departments of the investigation and statistics, the number of biological populations in Quanzhou Bay is currently about more than 2,200 species [2]. There are 191 species of higher plants of 5l families and 143 genera along the shoreline, as well as 186 species of plankton, 169 species of benthic organisms, 177 species of intertidal organisms, and 339 species of aquatic species [3].

In recent years, due to the deterioration of the water environment conditions, the number of some organisms has declined, the more obvious is the decline of mangrove forests, intertidal mangrove forests were widely distributed along the mouth of the Luoyang River, but since the 1980s to 1990s, the distribution area has decreased drastically, and is now only a small range of distribution in the east side of the Luoyang Bridge. Mangroves can supply sufficient nutrients for the coastal ecosystem, and have the function of "detoxification" for the sea area, and the result of its decline has caused extremely unfavorable impacts on the aquaculture and wild aquatic animals living environment in the area.

Another exotic organism, the mutualistic rice grass, has encroached on a large area of mudflat resources due to its strong vitality and habitability, and its ability to reproduce. In the growth area caused by the lack of oxygen in the water environment at the same time also produces the phenomenon of promoting siltation, has played a great role in destroying the living environment of aquatic organisms, resulting in a large number of marine organisms suffocated and died, affecting the Quanzhou Bay fishing and the development of mariculture industry.

Quanzhou Bay is the breeding base of pike crabs in Quanzhou City and an important source of constricted seedlings in Fujian Province, with the expansion of siltation in the bay, the quality of the water environment declined, will bring serious harm to the aquaculture industry.

3.3.2 Main factors affecting the distribution of biological resources

(1) The quality of the water environment directly affects the survival and distribution of biological species, and is the most important factor affecting biological resources. Excellent quality of the water environment, for the survival and development of living creatures to provide a good environment; deterioration of the water environment, so that biological survival environment is damaged. Biological pollution by the environment, and through the food chain, so that other organisms are also polluted, forming a vicious circle.

(2) Human engineering activities are also a major factor affecting biological resources. Human engineering activities cause water pollution, noise and the reduction of living space, etc., which directly affect the survival and distribution of biological resources.

(3) Other factors, such as the improper introduction of foreign species, resulting in changes in the ecosystem (mainly manifested in the region as the flooding of the mutualistic rice grass), biological species and distribution also changed.

3.4 Wetland ecological environment

Quanzhou Bay estuarine wetland is located in the estuary area of Jinjiang River and Luoyang River, which is formed by sediment deposition carried by Jinjiang River and Luoyang River and the sea, and the type of wetland substrate is dominated by muddy sandy and muddy texture, which belongs to typical estuarine mudflat wetland, and it is a typical representative of the subtropical estuarine mudflat in China. Wetlands within the open water, mudflat concentration, an area of more than 100,000 hectares, but also belongs to the southern subtropical oceanic monsoon climate zone, good natural geography, climatic conditions, nourishing a wealth of aquatic plants and animals, where plankton, benthic organisms, intertidal organisms and other types of rich biodiversity and favorable environmental and climatic conditions, but also attracted a lot of birds and birds in the habitat of this breeding [3], thus constituting a vibrant ecological environment.

Good ecological environment is based on superior natural conditions on the one hand, but also affected by human activities. For a long time, the area of frequent human activities, especially in recent years, large-scale production and construction such as railroads, highways and other construction in the near-estuary area across the Jinjiang and Luoyang rivers, coupled with the development of beach mariculture, as well as near-shore production of wastewater, waste incorporation, has been a considerable degree of destruction of the wetland ecological environment of the estuary, resulting in the reduction of wetland populations of living organisms, such as the previously mentioned mangrove forests, such as a sharp decrease in the distribution of the area. . In view of the current situation and causes, effective protection measures should be taken in time. Although Quanzhou Municipality has established a nature reserve in part of the wetlands of Quanzhou Bay estuary, the threat of environmental degradation of the wetlands still exists due to the lack of effective management. Therefore, protection efforts should be increased, such as gradually reducing the incorporation of near-shore pollutants, strengthening the protection and restoration of coastal mangrove forests, and standardizing beach mariculture operations, so that the ecological environment of the entire Quanzhou Bay estuarine wetlands can be significantly improved and good ecological functions can be restored.

3.5 Relative sea level rise and fall

3.5.1 Relative sea level rise and fall in Quanzhou Bay

Sea level along the coast of Fujian Province is generally dominated by the rise, but there are some differences in the local areas, and the distribution of large areas of lateritic terraces around the Quanzhou Bay is characterized by a long period of intermittent stability of crustal uplift, which has been demonstrated based on the observational data of the Earth's crustal deformation of the Seismological Bureau of Fujian Province ( According to the observation data of crustal deformation of Fujian Provincial Seismological Bureau (1972-1980), the rate of crustal uplift in Quanzhou Bay is about 4mm/a, and according to the relevant data, the rate of sea level change in Xiamen tide gauge station adjacent to Quanzhou Bay is 3.4mm/a after the revision of the equilibrium datum［4］, which can be seen that the change of sea level in Quanzhou Bay area is a relative decline (i.e., the relative uplift of crustal rise), and the rate of which is about 0.6mm/a. With the gradual warming of global climate, the absolute rate of sea level rise is increasing. With the gradual warming of the global climate, the absolute rate of sea level rise increases, the relative uplift of the crust in Quanzhou Bay area will gradually reduce the rate.

3.5.2 Hazards of the relative decline in sea level

Quanzhou Bay region, the relative decline in sea level, the earth's crust for the relative rise in the relative decline in sea level is a slow process, usually difficult to detect, but the accumulation of a long period of time, enough to Quanzhou Bay region, the construction of the economy, the city of municipal construction, the people's production and life brought about by a variety of aspects of the impact. On the one hand, the relative decline in sea level directly manifests the gradual exposure of near-shore tidal flats, and the water depth of the sea area becomes shallow; on the other hand, the relative decline in sea level makes the erosion datum decline and extend, resulting in the extension of the siltation range expansion, and the mouth of the siltation area erosion and scouring to form the intricate and complex phenomenon of scouring and siltation of the bay. Quanzhou Bay channel depth gradually become shallow, thus affecting the use of port engineering and flood control project foundation suffered scour damage, affecting the project's ability to resist disasters and other phenomena and the relative decline in sea level has a certain relationship.

3.5.3 The main factors affecting the relative decline in sea level in Quanzhou Bay

Regional crustal deformation is an important factor in the relative decline in sea level, although the factors affecting the rise and fall of sea level, such as the Earth's greenhouse effect, climate warming, seawater temperature, Antarctica, the North Pole, and high mountain glaciers, the ablation of the ice cap, and other phenomena will continue to exist, but the crust of the Quanzhou Bay region to lift the rate of large

4 Trend of geological changes in the ecological environment

(1) Due to the Jinjiang River, Luoyang River Basin soil erosion is still serious and the construction of port projects, sluice gate stopping the water, the relative decline in sea level and other influencing factors, Quanzhou Bay siltation will continue, if the influencing factors to be improved, the rate of siltation will be reduced until reaching the balance of siltation.

(2) With the increasing economic activities in the Jinjiang and Luoyang River Basin, wastewater and other discharges continue to increase, which will deteriorate its water environment. However, if strict environmental protection measures are indeed taken to treat wastes, wastewater, etc. in a harmless manner, the water environment will improve.

(3) The survival of biological resources is directly related to the water environment and human engineering activities, with the improvement of the water environment, human engineering activities are standardized and controlled as well as the protection of wetland resources, the living environment of the biological resources will be improved, and the biological populations will gradually expand.

(4) The crust of Quanzhou Bay area will continue to rise, but due to the enhancement of the global greenhouse effect, the rate of sea level rise will also increase, and the trend of relative sea level decline will gradually slow down, and even up to the trend of relative sea level rise.

5 Protection and rational development and utilization

Quanzhou Bay region for the ecological and environmental geological problems of the status quo, development trends and the main factors affecting, combined with the socio-economic development plan, the regional resource protection and development and utilization should follow the "root cause and cure the root cause, protective development and utilization" principle.

(1) to take measures to reduce the source of silt, increase the Jinjiang River, Luoyang River Basin soil and water conservation work. In particular, soil and water conservation work in the Jinjiang River Basin is a top priority, and effective supervision of mining, agricultural production activities and town construction in the basin to prevent the aggravation of soil and water erosion hazards. At the same time to strengthen the greening work, improve forest coverage, water storage and soil conservation, improve the ecological environment of the watershed.

(2) Reclamation of land, embankment construction should be rational planning, scientific evidence, in order to improve the hydrodynamic conditions of Quanzhou Bay.

(3) to strengthen environmental protection, speed up, increase industrial and domestic waste disposal, improve the centralized harmless waste disposal rate.

(4) Control the area of human activities, plan the scope of human activities, set up nature reserves, planning for breeding areas, etc.

(5) Strengthen the management of pesticides and fertilizers applied for agricultural use, and prohibit the application of pesticides and fertilizers that are highly toxic and difficult to degrade.

(6) Strengthen effective management of oil leakage and discharge from ships in water operations.

(7) The introduction of exotic biological species should be scientifically demonstrated and the pros and cons should be predicted.

(8) Establish a nature reserve of Quanzhou Bay, especially to strengthen the protection of estuarine wetlands. Functional zoning of Quanzhou Bay, such as in the Luoyang Bridge to Houzhu Harbor area set up as the core protection zone, Houzhu Harbor to the Razor Clam River area set up as a construction, production area, around the Quanzhou Bay area for the hunting of the peripheral protection zone. At the same time in the area of production and construction, especially the sea construction projects should be carried out the necessary environmental assessment and the necessary assessment of the risk of geological hazards and other work.

6 Conclusion

The main ecological and environmental geologic problems in Quanzhou Bay at present are siltation of the bay, degradation of the quality of the water environment, and destruction of the biological resources system. For its main influencing factors, corresponding protection and rational development and utilization should be carried out.

References

[1] Wang Renjun. Characteristics of COD self-purification and its causes in the estuarine waters of Jinjiang River. Taiwan Strait, 1996(1):48-53

[2] Ma Jingneng. An overview of biodiversity conservation in China. Beijing: China Forestry Press, 1998

[3] Huang Guoyong et al. Species composition and distribution of birds in the estuarine wetlands of Quanzhou Bay. Taiwan Strait, 2002(2):228-233

[4] Chen Zongyong, Zhou Tianhua et al. Changes in mean sea level along the coast of China. Beijing: Science Press, 1994

The Ecological Environment Geology and Protection Development in Quanzhouwan Region

Liu Bailing

(Geological Engineering Exploration Faculty of Fujian Province, Fuzhou 350002)

Abstract: On the basis of the evaluation on the current statement of eco- environment geology in Quanzhou Gulf , the thesis discusses the problems of the current statement of eco-environment geology , analyses the main formation factor, forecasts the trends of its development, then put forwards the reasonable policy on protection and development.

Key words. Quanzhou Gulf; Eco-environment geology; Biomass; Develop trends; Protection and development