Main problems and countermeasures of ecological environment in Hunan Province

Main ecological and environmental problems 1 1.3. 1

(a) Uneven social and economic development

The social and economic development of Hunan province is unbalanced, which can be divided into four levels: particularly developed areas, developed areas, developing areas, underdeveloped areas and poverty-stricken areas.

(1) Particularly developed areas: Changsha, Zhuzhou, Xiangtan and Yueyang, with per capita GDP exceeding 10000 yuan (including Changsha exceeding 20000 yuan), and the average annual net income of farmers exceeding 3000 yuan.

(2) Developed areas: There are 465,438+0 counties and cities in developed areas, which are mainly distributed on both sides of the Beijing-Guangzhou line and spread in the north-south direction. There are also some developed counties and cities in Xiangxi and Xiangbei. Per capita GDP+ average annual income of farmers is more than 6000 yuan, of which the average annual net income of farmers is mostly higher than 2000 yuan.

(3) Developing areas: There are 24 counties and cities in developing areas, which are mainly distributed in the transitional zone between the hills in central Hunan and the surrounding mountainous areas, as well as the counties and cities in the transitional zone between the Dongting Lake Plain and the mountainous areas on both sides of the strait. Per capita GDP in developing regions and per capita annual income of farmers are 4850 ~ 6000 yuan.

(4) Poverty-stricken areas: including 100 counties (Yongshun, Baojing, Pingjiang, Sangzhi, Xinhua, Yuanling, Huayuan, Anhua, Longhui and Xintian) listed in National Development (1994) and Hunan Xiangfa (1994).

(2) Dense population

In recent decades, the population of Hunan has increased dramatically. During the 45 years from 1953 (a census) to 1998, the population of the whole province increased by 31523,000, with an average annual increase of more than 700,000, which made the natural environment and natural resources under increasing pressure, and the relationship between population growth and environmental resources became increasingly tense. As far as land resources are concerned, in 1949, the per capita land area in the province reached 10.64 mu, and the per capita cultivated land area reached10.76 mu. By 1998, the per capita land area and cultivated land area decreased to 4.89 mu and 0.74 mu respectively, which were equivalent to 46% and 44% of 1949 respectively. Obviously, a large population and little land is one of the most prominent contradictions in the process of economic development and land development and utilization in Hunan Province. In addition, the ecological and environmental problems brought by population growth include the decline of forest coverage, the decrease of biological resources, the intensification of soil erosion, frequent geological disasters and serious environmental pollution.

land deterioration

(1) Aggravated soil erosion: Granite, purple sand shale and sandstone have little cohesion, and most of them are slopes, so soil erosion will occur in the rainy season at the turn of spring and summer. Especially due to unreasonable human activities, low vegetation coverage and unreasonable reclamation and cultivation, soil erosion has been aggravated. Soil erosion has brought a series of damages to soil resources and agricultural production, and reduced soil fertility. According to statistics, the province loses about 65.438+700 million tons of soil every year, which is equivalent to the soil loss of 800,000 mu of cultivated land, and the accompanying organic fertilizer loss is about 2.48 million tons.

(2) The process of soil incubation is enhanced: due to the lack of investment in long-term water conservancy construction, the leakage of reservoirs and canals, and the imperfect drainage facilities, especially the cultivation techniques of heavy irrigation and light drainage and the long-term continuous cropping system of double-cropping rice, the soil has been flooded for a long time and the exposure opportunities are few. At the same time, the integrated cultivation method of hydroponics and hydroponics makes the plough bottom layer more and more dense, with poor air permeability, and the reducibility of some or all soil layers is enhanced, thus the secondary incubation process generally occurs. There are more than 500,000 hectares of potential paddy fields in the province, and more than 270,000 hectares of secondary potential paddy fields.

(3) Land poverty is common: land poverty is caused by the imbalance between land use and nutrition. In recent decades, with the development of intensive agriculture, the consumption of land nutrients has increased sharply, while the land investment is relatively insufficient, and the phenomenon of repeated use while ignoring farming or even only using it without farming is widespread, resulting in serious loss of soil nutrients. In the whole province, the organic matter content of most of the dry land of 1.2299 million hectares is lower than 1%, and the organic matter content of a considerable number of paddy fields is lower than 2%. In areas with relatively developed agricultural production and high agricultural production level, such as Changde, Yueyang and Changsha, the phenomenon of land poverty is more obvious, and low-yield cultivated land accounts for more than 70% of its total cultivated land area.

(4) Serious land damage: Due to the continuous expansion of industrial and agricultural production and the rapid development of urbanization and traffic construction, land damage caused by excavation, collapse and occupation has generally occurred. According to incomplete statistics (1995), the total area of land excavated or occupied by large and medium-sized state-owned industrial and mining enterprises in the province over the years is1.10.3 million hectares, and the total length of the double-track project of Hunan-Guizhou Railway in Anhua County is only 38 kilometers. During the construction period, waste soil and waste residue piles occupied 74,400 square meters of land, rivers and water.

(d) Functional decline of rivers, lakes, ponds and reservoirs

(1) Increased sediment concentration and sediment transport: In the rainy season of spring and summer, especially in the rainy season of heavy rain and heavy rain, serious soil erosion occurred in the middle and upper reaches of each basin in the province, and a large amount of sediment was transported downstream by surface runoff. At this time, the sediment concentration and sediment transport of large and small rivers generally increased. The annual average sediment concentration in the main streams of Hunan, Zitong, Yuanshui and Lishui are 0. 179 kg/m3, 0. 127 kg/m3, 0.229 kg/m3 and 0.4 16 kg/m3 respectively. From the late 1960s to 1980s, only the main stream of Xiangjiang River imported 65,438+into Dongting Lake every year.

(2) The reduction of water conservancy benefits: mainly manifested in the reduction of flood storage, flood control, drought resistance and power generation benefits of rivers and lakes. For example, the natural lake area of Dongting Lake was 4350 km2 in 1949, and it was reduced to 269 1 km2 in 1983, which was 38% lower than 1949, and the lake capacity was also reduced by 40%. Subsequently, floods occurred in Dongting Lake Plain every rainy season, especially in recent years, which seriously affected people's lives and property safety and daily life.

(3) Reduced river transport capacity: Due to long-term soil erosion, river siltation and river bed elevation, the shipping capacity and shipping value are greatly reduced. There are 594 rivers with a drainage area of 100 km2 in Hunan province, with a total length of about 33,000 km and a navigable mileage of 1965 reaching 16000km. Later, due to sediment deposition, the riverbed became shallow and the navigation mileage decreased year by year. At present, the navigable mileage of rivers in Hunan Province is only about 100 km, and the passenger and freight volume has dropped significantly.

(E) Frequent geological disasters

(1) Landslides and collapses: Landslides and collapses are relatively developed in the province, with thousands to tens of thousands of occurrences every year, of which about 1% can cause disasters. According to statistics, there have been 764 landslides and collapses 1 10 in the whole province, which are concentrated in mountainous and hilly areas, especially between 150 ~ 800 m above sea level. The northwest Xishan area of Shimen-Yuanling-Fenghuang line in northwest Hunan, the southwest mountainous area of Anhua-Tongdao and the southwest mountainous area of Chaling-Linwu-Jianghua are rich in landslides and collapses, accounting for 35.2%, 20.8% and 25.2% of the total landslides and collapses in the province respectively, and are also the main development areas of large-scale landslides and collapses. The valley slopes on both sides of the main streams of Hunan, Zizi, Yuan and Li and their first tributaries are also areas where landslides and collapses often develop.

(2) Debris flow: Debris flow often occurs simultaneously with landslides and collapses in the province, but the number is relatively small. According to the data of the Department of Geology and Mineral Resources, there are 74 debris flows with a single solid mass > 1 000 cubic meters, including 22 large and giant ones.

(3) Soil erosion: Because most areas of the province belong to mountainous and hilly areas, the terrain is relatively high, the relative height difference is relatively large, and there is a lot of rain with high intensity, especially in the widely distributed red beds and magmatic rocks, as well as Silurian shale and mudstone distribution areas, the bedrock has little adhesion to the soil, and its corrosion resistance, erosion resistance and weathering resistance are weak. Once the vegetation is destroyed, soil erosion will easily occur. Therefore, soil erosion exists for a long time. 65438-0985 The research results of agricultural regionalization in Hunan Province show that soil erosion is widely distributed in Hunan Province, reaching 44,000 km2, accounting for 20.8% of the total area of the province. According to erosion type: surface erosion 4 1958.6 km2, gully erosion 1673.7 km2, collapse 368.3km2, agricultural land 6954.3 km2, forest land 273 12.5 km2, grassland 9733.8km2, according to loss degree: 20830.8km2. ..

Since the 1980s, forest vegetation and grassland have been well maintained due to closing hillsides to facilitate afforestation and implementing the contract responsibility system of joint production, and the vegetation coverage rate has increased year by year, reaching 52% in 1996, which not only effectively curbed the further expansion of soil erosion, but also reduced the degree and scope of soil erosion in areas where soil erosion has occurred. However, soil erosion is still widely distributed in the whole province. Except Anxiang, Nanxian, Yuanjiang, Huarong and Jinshi in Dongting Lake Plain, soil erosion occurred in other areas to varying degrees. The area of soil erosion in the province is 39430 km2, accounting for 18.62% of the total area of the province. The areas with serious soil erosion are Hengyang, Shaoyang, Autonomous Prefecture and Loudi City, accounting for 25.7%, 24. 1%, 25.0% and 23.4% of the total area respectively. The soil erosion in Hengyang is the most serious, accounting for 43.2% of the county's total area, forming a large area of red soil wasteland.

Soil erosion in Hunan Province is dominated by surface erosion, accounting for 95.36% of the total loss area. There are cultivated land, forest land and grassland wasteland, of which cultivated land loss accounts for 15.8%, forest land accounts for 62. 1% and grassland wasteland accounts for 22. 1%.

(vi) Surface water pollution

Xiangjiang River System: 1998, Xiangjiang River System has 20 main river sections and 12 tributary sections. Three sections in the whole basin meet the first and second water quality standards, each accounting for 9%; There are 5 sections meeting the Class III water quality standard, accounting for15%; There are 17 sections, accounting for 53%; Four sections belong to the water quality standard of class V, accounting for 12%. The water pollution in the middle and upper reaches of Xiangjiang River is relatively light. There are 1 1 monitoring sections (9 urban river sections) in the 400 km long river section from the source of Yongjiangkou in Yongzhou to the upper reaches of Zhuzhou. Only 1 section meets the Class III water quality standard, and the rest sections belong to Class IV or above.

Among the tributaries of Xiangjiang River, Chen Jiang, Steamed Water, Liuyang River and Lianshui are seriously polluted, and the water quality of Xiaoshui and Fuling is kept good. The main pollutants in Xiangjiang waters are total nitrogen, petroleum, total coliforms, ammonia nitrogen, total phosphorus, nonionic ammonia, mercury, arsenic and other heavy metals.

Zijiang River System: Zijiang River is a seriously polluted river system in the main stream and tributaries of Hunan Province. 1998, this assessment involves 15 sections (urban reach 13 sections), with 1 1 sections for the main stream and 4 sections for the tributaries. Of all the sections, 2 sections meet the first-class water quality standard, and 165438 section belongs to the fourth-class water quality standard. Only Zhexi Reservoir and Taogushan in the middle reaches of the main stream have good water bodies, which meet the first-class water quality standards. The nine water quality monitoring sections in the middle, upper and lower reaches all belong to Class IV water quality standards. The tributaries of Shaoshui and Fuyi have been seriously polluted by water. The water bodies of two sections with little water participating in monitoring and evaluation belong to Class V water quality standard, and those with rich water participating in monitoring and evaluation belong to Class IV water quality standard. The main pollutants in the main stream are petroleum, volatile phenol, total coliform bacteria and total phosphorus. The annual average values of biochemical oxygen demand, total coliform bacteria, total phosphorus and volatile phenol in Majiaba and Dongfeng Bridge tributaries of Shaoshui exceeded the standard.

Yuanjiang River System: Yuanjiang River System has 16 monitoring sections, with the main stream 1 1 and five tributaries. Of all the sections involved in monitoring and evaluation, 5 sections meet the first class water quality standard, 2 sections meet the second class water quality standard, 1 section meets the third class water quality standard, 5 sections meet the fourth class water quality standard and 3 sections meet the fifth class water quality standard. The water quality in the main stream of Yuanjiang River is still good. Of the 1 1 sections set on the main stream with a total length of about 500 kilometers, only the 1 section in the middle reaches and the two sections in the lower reaches belong to Class IV water quality standards, and the water bodies in other monitored sections meet Class I, II or III water quality standards. Wushui, Dongjiang and Wanrong rivers, tributaries of Yuanjiang River, are seriously polluted. The main pollutants are total coliform bacteria, total phosphorus, volatile phenol, ammonia nitrogen and suspended solids. The total coliform bacteria, total phosphorus and ammonia nitrogen in the monitoring projects of Wanrongjiang, Shangzhou and Qiyi chemical plants in the tributaries exceeded the standard year by year, and the total coliform bacteria in Xinxingzui and Potou sections in the lower reaches of the main stream exceeded the standard respectively.

Lishui River System: There are 6 monitoring sections in Lishui River System, with 5 main streams and 5 tributaries 1. On the main stream, only the section of Shimen Sanjiangkou meets Class II water quality standards, and the other four sections belong to Class IV water bodies. The water body in the upper part of the tributary basically meets the Class III water quality standard. The main pollutants in Lishui waters are ammonia nitrogen, suspended solids and coliforms.

Dongting Lake Area: There are 8 sections participating in the evaluation in Dongting Lake Area, 6 sections belong to Class IV water quality standard, and 2 sections meet Class III water quality standard. The pollution range of total phosphorus and total nitrogen is large, showing eutrophication. The main pollutants are total phosphorus, total nitrogen, suspended solids, chromaticity and total coliforms. Among all monitoring sections in the lake area, Nanzui and Maocaojie sections are seriously polluted.

Yangtze River system: There are three sections in Hunan section of the Yangtze River system, namely Jingjiang Estuary, Lucheng and Chenglingji in Yueyang City, and the monitoring results of these sections all belong to Class IV water quality standards. The main pollutants are total phosphorus, total nitrogen, total coliforms, suspended solids and ammonia nitrogen.

The monitoring results of other major reservoirs in Hunan Province show that the water quality is good except for the annual average value of volatile phenol in Shuangpai Reservoir, a tributary of Xiangjiang River.

(7) Air pollution

According to the statistics of Hunan Environmental Protection Bureau, the pollution load of industrial waste gas from key sources in our province is 38 19432.40, of which combustion waste gas accounts for 68.98% and process waste gas accounts for 3 1.08%. It shows that more than two-thirds of industrial waste gas from key sources comes from combustion waste gas.

Sulfur dioxide, nitrogen oxides and soot are the main pollutants with heavy pollution load, which are 1879829.73, 963959.00 and 68097 1.878 respectively. The cumulative load ratio of these three pollutants is 95.37%.

Among the pollution loads of industrial waste gas from key sources, Yueyang ranks first in Hunan Province, with the standard pollution load of 729 126.90, accounting for 19.09%, followed by Loudi 16.54% and Zhuzhou 14.5 1%.

1 1.3.2 ecological environment improvement measures

(a) Give priority to the development of economically developed areas, strengthen inter-regional cooperation, and narrow regional development differences.

Regional economic development should take the road of unbalanced growth. Only in this way can we concentrate limited funds, manpower and material resources, make key breakthroughs in the field of advantageous development, and then implement rolling development.

Due to the differences in social history, natural conditions, resource conditions, investment scale and other factors, there are obvious differences in the level of social and economic development in the province. On the whole, the social and economic development level of hilly areas in central Hunan and Dongting Lake area in the middle and lower reaches of Xiangjiang River is obviously higher than that of northwest Hunan, Xuefeng Mountain area in western Hunan and southern Hunan. In the future, we should give priority to the limited funds, manpower and material resources to ensure the advanced development of socio-economically developed areas. The areas along the Beijing-Guangzhou Railway and the Beijing-Zhuhai Expressway, especially those centered on Changsha, Zhuzhou and Xiangtan, have high productivity, Guangdong, Hong Kong and Macao in the south and the golden waterway of the Yangtze River in the north, with developed industry, agriculture and commerce, large towns, convenient transportation, developed science, education, medical services, posts and telecommunications, abundant water resources, low investment, high economic benefits and rapid development, and should be regarded as the priority development areas in the province to enhance agglomeration.

While giving priority to the development of economically developed areas, it is necessary to strengthen regional cooperation. Realizing the common prosperity of all regions is the goal of socialist construction. At the same time, the backward mountainous areas in this province are rich in land resources, and the serious social and economic lag will restrict the sustainable development of developed areas. For poverty-stricken areas and ethnic minority areas such as Xiangxi Autonomous Prefecture, according to their land and resources conditions, according to the principles of adjusting measures to local conditions, complementing each other's advantages, rational division of labor, highlighting key points, giving full play to their advantages, and coordinating development, we will carry out counterpart poverty alleviation work, speed up the poverty alleviation of the province's 3 million people, narrow the gap between the rich and the poor with socially and economically developed areas, and gradually realize common prosperity.

(2) Strengthen family planning and control population growth.

Controlling population growth is one of China's basic national policies, and it is also a major event related to Hunan's overall social and economic situation and future generations. A large population and little land is one of the most prominent contradictions in the process of economic development and land development and utilization in Hunan Province. At present, the age structure of the population is changing from young to adult, but the population base of teenagers and adults is still very large, and the total burden coefficient is also higher than the national average 1.23%( 1995). If family planning is relaxed, the juvenile population will expand rapidly, the construction achievements will be partially or mostly offset by population growth, and the resources and environment will also bear greater pressure. Therefore, we should continue to strengthen the management of population and family planning, improve the responsibility system of population target management, improve the family planning work network at the grassroots level, strictly implement family planning laws and policies, and combine the implementation of family planning with economic development.

(3) Planting trees and grass, renovating rivers and lakes and curbing geological disasters.

Planting trees and grass to curb soil erosion: low forest coverage and grassland degradation are one of the important reasons for the intensification of geological disasters in Hunan Province. Therefore, it is one of the most important basic measures to improve the ecological environment and economic conditions to continue afforestation and grass planting and develop vegetation. The forest coverage rate in Hunan Province is 52%, which is much higher than the national level. However, due to the large terrain and heavy rainfall in most areas, especially heavy rain and heavy rain, geological disasters still occur from time to time. At the same time, the primary forestry has been fully developed, and the existing forests are mostly secondary forests, mainly Pinus massoniana, Chinese fir and economic forests, and the role of inhibiting soil erosion is obviously weakened. Therefore, it is necessary to strengthen the implementation of the Forest Law, manage forests according to law, close hillsides to facilitate afforestation, adjust forest species structure, expand the planting area of shelter forests, and ensure that forests are truly improved not only in quantity, but also in quality, improve soil and water conservation capacity and improve the ecological environment. Grassland degradation in Hunan Province is obvious. Due to the unreasonable exploitation and utilization of grassland by human beings, a large area of grass slopes have been reclaimed and public beaches have been overgrazed. In addition, regardless of objective conditions, grasslands have been destroyed for afforestation. It leads to the failure of grassland reclamation, the desolation of public beaches and the failure of afforestation, which leads to grassland degradation. Therefore, measures such as fencing, returning farmland to forests and grasslands should be taken to give the grass enough time to recuperate and sprout; Implement comprehensive protection measures of synchronous development and interactive layout of shelter forest and grassland, gradually restore grassland development and improve ecological conditions.

Harness rivers, lakes and reservoirs to curb floods: Whenever there is concentrated rainfall and abundant water in spring and summer, when the four rivers flood and the Yangtze River flood enter the lake respectively, it will cause floods in Dongting Lake Plain and low-lying and flat areas in the lower reaches of the four rivers. There are many reasons. There are three main reasons: first, the water storage and flood control capacity of Dongting Lake has been greatly reduced due to the reclamation of Dongting Lake; Second, due to long-term soil erosion, the sediment concentration and sediment transport in Surabaya and Dongting Lake have increased, rivers have silted up, the riverbed of lakes has risen, and the flood discharge and flood control capacity has decreased significantly; Third, the middle and upper reaches of the four rivers have low water storage regulation capacity. Therefore, we must rectify the rivers and lakes.

First of all, build a number of large and medium-sized reservoirs in the middle and upper reaches of the four major rivers of Hunan, Zi, Yuan and Li and their important tributaries, especially in rainstorm centers or high precipitation areas, strengthen the maintenance and management of the built reservoirs, improve the water storage capacity of the upstream and downstream of the four major rivers, realize free regulation of flood control and drought relief, and reduce the flood control pressure of Dongting Lake and Sishui Road.

In the middle and lower reaches of the four major rivers of Hunan, Guizhou, Yuan and Li, areas with river siltation and river bed elevation should be dredged to achieve smooth water flow and lower water level. At the same time, it is necessary to strengthen the dams along the river to reach the flood control capacity standard of once every 20 years or even higher. Especially in key cities with developed social economy, such as Changsha, Zhuzhou, Xiangtan, Hengyang and other cities, the dike reinforcement along the river should meet the flood control capacity standard of 50 ~ 100. In addition, it is necessary to ensure that key railways and important highways are not flooded and open all year round.

Reclaiming land around the lake and raising the sediment-laden lake bed have greatly reduced the flood control capacity of Dongting Lake, which is the crux of the flood disaster in Dongting Lake Plain and Sishuiwei. Therefore, it is necessary to return the farmland to the lake and clean up the spillway around Surabaya. In addition, it is necessary to strengthen dam construction and enhance the drainage capacity of dikes.

(4) Comprehensive control of water pollution

(1) Strengthen macro-management, improve the supervision mechanism, and fully implement the system of dynamic declaration of pollutant discharge and pollutant discharge permit in the whole province.

(2) Adjust the industrial structure, support the environmental protection industry, adopt the policy of closing, stopping, merging and transferring for enterprises with serious pollution, and adopt the policy of regional centralized production and prudent development for industries with serious pollution such as chemical industry, metallurgy and paper making.

(3) Control the polluters and strengthen the supervision and management of sewage treatment facilities. If the existing sewage treatment facilities are not operating normally, they should be rectified within a time limit, and the facilities with poor treatment effect should be technically improved to meet the discharge requirements as soon as possible.

(4) Strengthen the management of water resources, vigorously promote water conservation, improve the reuse rate of water, and reduce the water consumption and emissions per 10,000 yuan output value and unit product.

(5) Strengthen the investment in urban domestic sewage treatment, build and expand domestic sewage treatment plants, and strictly control domestic sewage discharge.

(5) Comprehensive control of air pollution

(1) Focus on controlling soot pollution and comprehensively control air pollution. Enterprises, civil boilers and stoves that do not meet the national smoke emission standards should be treated within a time limit. Promote energy-saving and efficient furnaces and kilns with little pollution.

(2) Gradually change the fuel structure, actively develop gas fuel, and improve the city gas consumption rate. Conditional, should actively promote the use of solar energy, biogas and other pollution-free energy.

(3) Strengthen the control and management of automobile exhaust, prohibit vehicles whose exhaust emission does not meet the requirements from driving on the road, and reduce automobile exhaust pollution.

(4) All kinds of waste gas discharged by industrial and mining enterprises should be treated or recycled in combination with technological transformation. Serious pollution should be treated within a time limit and discharged up to standard.