Measures and experiences for Ecological Restoration: Case of Heihe River Basin in China
Cao Jianting
(General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, People’sRepublic of China)
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Abstract: Mainly impacted by unreasonable development of natural resources, Haihe river basin experienced serious ecological degradation in the later 20th century, urgent requiring ecological restoration from points of river basin. Comprehensive measures, implemented in the upper, middle and downstream of the river basin for ecological restoration, were reviewed in accordance with relating plan. The restoration outcomes and experiences for this ecological restoration were summarized for other basin ecological restoration.
Key words: water allocation, water conservation , ecological restoration, Haihe River Basin
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Measures and experiences for EcologicalRestoration: Case of Heihe River Basin in China
Cao Jianting
(General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, People’sRepublic of China)
Email:
Abstract: Mainly impacted by unreasonable development of natural resources, Haihe river basin experienced serious ecological degradation in the later 20th century, urgent requiring ecological restoration from points of river basin. Comprehensive measures, implemented in the upper, middle and downstream of the river basin for ecological restoration, were reviewed in accordance with relating plan.The restoration outcomes and experiences for this ecological restoration were summarized for other basin ecological restoration.
Key words: water allocation, water conservation , ecological restoration, Haihe River Basin
1. Basic information on the basin
The Heihe River is the second longest inlandriver in Northwest China, and the river basin adjoins the Shiyang River Basin in the east and the Shule River Basin in the west, and extends to the Juyan Lake in Ejina County in Inner Mongolia and borders the People's Republic of Mongolia in the north. The basin is located between 98°～102°east longitude and 37°50'～42°40' north latitude,and coversthe three provinces (autonomous regions) of Qinghai, Gansu and Inner Mongolia, with a total land area of about 140,000km2.
The Heihe River originates in the northern foot of Qilian Mountains, and its main stream is 821km long. The section above the Yingluo Gorge is the upper reaches of the river, which is 303km long and covers an area of 10000 km2. On both sides of the river are high mountains and deep valleys, and the riverbed is steep. The climate is wet and cold, the vegetations grown well. The average annual temperature is less than 2℃, and the annual precipitation is 350mm. The upper reaches area is main contributing region of water resources within the Haihe River Basin.
The middle reaches starts from the Yingluo Gorge and ends at the Zhengyi Gorge, with a total length of 185km and an area of 25600 km2. The terrain on both sides is flat. There are abundant light and heat resources, but the climate here is characterized by severe droughts, with annual precipitation of only 140mm and annual evaporation of 1410mm. The area of artificial oasis is larger and the soil in some area is seriously salinized and alkalinized.
The section downstream of the Zhengyi Gorge is the lower reaches, which is 333km long and covers an area of 80400 km2. Except both river bands and the Juyan Delta, most areas are desert and Gobi areas, with annual precipitation of only 47mm and annual evaporation of up to 2250mm. The climate is very dry, with arid index reaching 47.5. The lower reaches belongs to an extreme arid zone, with very serious wind-sand harms occurs frequently, and is one of the main sources of sandstorms in Northern China.
In social and economic aspects, the Heihe River Basin covers 10 counties (cities), including Qilian County in Qinghai Province, Sunan, Shandan, Minle, Zhangye, Linze, Gaotai and Jinta in Gansu Province and Ejina in the Inner Mongolia Autonomous Region. Before implementing the restoration plan (1999), the basin had a population of 1.34 million, 4130000 mu of arable land, 3070000 mu of farmland irrigation area and 860000 mu forest and grass irrigation area, and its per capita GDP was 4709 yuan RMB.
2. The ecological environment status and main problems before restoration
2.1 The ecological status of the basin
The upper reaches of the Heihe River Basin cover an area of 10000 km2, among which the mountainous areas account for 72%, the river terraces for 27% and theoases and hills for 1%. The area is located in a high and cold mountainous area, where plants grow slowly. The middle reaches of the river cover an area of 25600 km2, among which the Gobi and desert areas account for 31%, the soil beaches for 29%, the oases for 24%, and the low mountains and hills for 16%. The area is rich in light and heat resources and developed artificial oases. The lower reaches have the most vulnerable ecological environment, and its existing land area is 80400 km2, which are mainly Gobi, deserts and erosion mountains, accounting for 94%. Nearly half of land has been desertified, and the oases account for only 6%. The water quality in the Heihe River Basin is good, but the water quality in part of the middle reaches of the river is showing a deterioration trend.
2.2 Main ecological problems
Affected by climate and human activities,the ecosystems in the upper, middle and lower reaches of the Heihe River Basin are degrading to different extents.
In the upper reaches, thelower timber line of the forest belts have shrunk,the natural vegetation covers have degraded, and the biodiversity has been reduced. The woody lands of Qilian Mountains in the basin were only about 100mu at the beginning of the 1990s, a decrease of approximately 16.5% compared with 1950. The elevation of the lower tree line of the forest belts has shrunk from 1900m to 2300m. In the territory of Shandan County, Gansu province, the lower timber line of the forest belts has drawn back to2.9km on average.
The artificial forests in the middle reaches have developed well. In some parts, the artificial forests can effectively prevent the invasion of desert, and desertified lands have been turned into artificial oases, but land desertification in the area is showing a growing trend in general, and the speed of desertification is greater than the control speed. For example, in Gaotai County, the speed of desertification is 2.2 times greater than the control speed. In addition, due to unreasonable irrigation and drainage, land salinization is serious in some areas, and the water in some river sections is seriously polluted. According to statistics, the area of salinized arable land in the three counties of Zhangye, Linze and Gaotai reaches about 230,000mu.
The ecological problems in the lower reaches are most serious, which are mainly reflected in the following aspects:
(1) The drying up of river course isaggravating, the lakes have dried up, and the groundwater level is declining. The drying-up time of the cross section at Langxin Mountain in the lower reaches of the Heihe Riveris increasingly longer, the drying-up time of the Heihe River in the lower reaches has increased from about 100 days in the 1950s to nearly 200 days, and the drying-uplength of trail channel is also showing a growing trend.The area of water surface of West Juyan Lake and East Juyan Lake were 267km2 and 35km2 respectively in the 1950s, and they had been dried up successively in 1961 and 1992. Since the 1960s, many springs and marshes have disappeared, the underground water level in the lower part of the delta has declined, and the degree of mineralization of water is increasing.
(2) The area of natural forests has reduced significantly. From 1958 to 1980, the area of Populus euphratica, Elaeagnus angustifolia and Tamarix in the delta area in the lower reaches has reduced by 860,000mu, with an average annual reduction of about 39000mu. From the 1980s to 1994, the woody lands with vegetation cover of more than 70%reduced by 2.88 million mu, with an average annual reduction of about 210,000mu. The area of Populus euphratica forest reduced from the 750,000muin the 1950sto 340,000mu at present. The existing natural arbour forests are mainly scattered woodlands and scattered trees, with extremely poor viability. The Haloxylon ammodendron forest in the lake basin area also showsstubble-spot-like desertification.
(3) Grasslands are seriously degrading. Since the 1980s, grass and shrub lands in the delta areas have decreased by approximately 78%, and meadowsand grasslands with coverage between 30% - 70% and grasslands with higher yield on lake basins, low lands and marshes decreased by about 40%;desert grasslands, deserts and Gobi areaswith coverage less than 30% have increased by 68%. Herbaceous plant species have greatly reduced. The succession of grassland plant communities from the original wetland and mesophytic glass communities to desert grassland communities have also occurred.
(4) Land desertification and sandstorm hazardsare aggravating. During 1960~1980, the Gobi and desert areas with vegetation coverage less than 10% in Ejina County increased about 462km2, an average annual increase of about 23km2. With the increase of desertified land area, sandstorm hazardsare aggravating, affecting Northwest China, North China, Northeast China, and even East China and other regions, with a total area of about 2000000 km2.
The cause of ecological problems downstream is many aspects, but the fundamental oneis the problem of water shortage, especially the ecological water was deprived by the agricultural irrigation in the middle reaches.
3. Related measures for ecological restoration in the Heihe River Basin
The ecological deterioration in the Heihe River Basin has aroused widespread attention of the government and the various circles of the society in China.To solve the increasingly deteriorating ecological environment problems in the Heihe basin, the State Council approved the Near-term Improvement Plan for the Heihe River Basin in 2001[1]. The ecological restoration of the Heihe River Basin, as important contents, has been included in the Near-term Improvement Plan for the Heihe River Basin, and the relevant improvement projects have been implemented in Qinghai, Gansu and Inner Mongolia respectively.The relevant contents of the plan and the engineering measures and non-engineering measures implemented will be introduced below.
According to the objectives of coordinated development of population, resources, environment, economy and societyinthe Heihe River Basin and the general requirements of the implementation of the strategy for development of the western regions, the plan carried out in-depth study on the main problems of water resources development and utilization, ecological construction and environmental protection in the Heihe River Basin, analyzed the relationship between water and social stability, economic development, ecological construction and environmental protection and other aspects, put forward the guiding principles, general arrangements, near-term implementation opinions and relevant guarantee measures for comprehensive control of the Heihe River Basin.
(1) The guiding principlesfor comprehensive control of the river include:to take ecological construction and environmental protection as the fundamental tasks, focus on scientific management, reasonable allocation, efficient utilization and effective protection of water resources, make overall planning for the middle and lower reaches,adopt engineering and non-engineering measures, attach equal importance to ecological benefits and economic benefits, coordinate water for living, production and ecological purposes, and make full use of legal, administrative, economic, technological, educational and propaganda measures to carry out comprehensive control and restoration.
(2) The plan puts forward the measures of control by stages and the corresponding control objectives in 2003 and 2010.The control objectives in the near terminclude:to establish and improve the integratedwater resources management and ecological construction and environmental protection system, promote water conservation, adjust the economic structure and agricultural planting structure, reasonably arrange ecological water allocation, realize the water allocation plan approved by the State Council, bring the water discharge in normal yearsat Zhengyi Gorge to 950 million m3 and ecological water use in the entire basin to 730 millionm3, and stop the deterioration of the ecological systems.By the end of 2010, we will further strengthen efforts in saving water and adjustment of economic structure, intensify management, rationally allocate water resources, bring the ecological water consumption in the entire basin to 990 million m3, gradually increase the water flow to the downstream river delta areas and the Juyan Lake, strengthen the protection of the upstream natural forests and the construction of windbreak and sand-fixation forest in the middle reaches, and restore the ecosystemsto the levels in the 1980s. After 2010, we will take comprehensive measures, such astrans-basin water diversion and scientific allocation of water resources,to restore the ecological systems.
(3) The general arrangement for comprehensive control of the river basin is: to focus on strengthening the protection and construction of natural grasslands in the upper reaches; establish thestate-level water-saving agricultural demonstration zones, deepen the institutional reform in irrigation districts, carry out water-saving modification and positively adjustthe economic structure and agricultural planting structure in the middle reaches; establish the state-level ecological protection demonstration zones, strengthen the construction of artificial oases and improve the ecological construction and environmental protection in the oasis areas in Ejina. Through the construction of upper, middle and lower reaches, the comprehensive ecosystem management and protection system which focuses on rational allocation of water resources will be gradually formed.
Ecological environment construction in the upstream source area. The upstream source areais located in Qilian Mountains, and its ecological restoration and construction will focus on strengthening forestry engineering construction and comprehensive management of grassland and improving the vegetation coverage. The contents of ecological engineering construction include: grassland enclosure and cultivation 1.8 million mu; black soil beach and desertified grassland control 350000 mu; natural forest enclosure and cultivation 600000 acres; artificial afforestation 100000 mu; ecological migration 432 people and supporting electromechanical well construction and low pressure pipe irrigation in migration areas 5000 mu.
Water conservation and rehabilitation in Dingxin Irrigation District the middle and lower reaches. To solve the main problems in the middle reaches and Dingxin Irrigation District, we will determine the water-saving reconstruction tasks in irrigation districts, including canal system and field construction, abolishing and limitingwater storage in reservoirs in plain areas, newly building electromechanical wells and moderately developing a certain scale of projects for water-saving and returning farmland to forest and grass. The main contents of water saving reconstruction include: water diversion portcombination and canal system adjustment, abolition of 23diversion ports before 2010, and combination and reduction of 22canals; canal lining and building project reconstruction, including completing the lining of 625km, 730km and790km of stem, branch and lateral canals, with lining rate up to 80%, 70% and 60%, completing the construction of more than 8000new supporting buildings; completing 1.28 million muof field matching; newly building 1500 electromechanical wells, increasing the project measuresfor groundwater utilization and its exploitation size; proposing saving water by new and high technologies, increasing the scale of spray irrigation, micro irrigation and pipe irrigation, and completing water-saving irrigation area of 720,000 mu.
Constructing the ecological environment in the middle reaches. The water consumption for agricultural irrigation is great in the middle reaches, and ecological water consumption is occupied, so we should further build shelterbelts and windbreak and sand fixation forests, protect the quality of water environment, and establish the efficient, stable and sustainable development agricultural oases while positively strengthening water consumption management and promoting water saving supporting reconstruction and returning farmlands to forests and grasslands.
Constructing the ecological environment in the lower reaches. The ecological environment in the lower reaches of the Heihe River is most fragile, and the protection and restoration pressure is greatest.We should, based on the improvement of the traditional farming methods, maximize the protection and restoration of vegetation, curb the deterioration of ecological systems, and gradually establish ecological systemsthat cycle virtuously. The contents of ecological engineering construction include: poplar enclosure and cultivation 300000 mu; relocation of about 1500 herdsmen living in populus euphratica forest areas; construction of 40000 mu forage bases and supporting electromechanical wellsin Ejina and the Juyan delta oasis based on the ecological migration projects.
(4) Non-constructive measures. Besides constructive measure, non-constructive measures are also employed in river basin restoration.
Establishing the management system that combines basin management and regional management. The approval opinions of the Near-term Improvement Plan for the Heihe River Basin further specify the division of administrative powers in basin management and regional management and stipulate that:“theHeihe Basin Administrative Office of the Yellow River Water Conservancy Committee is responsible for integrated management and scheduling of the water resources of the Heihe River; arranging the implementation of the water abstraction permit system, formulating water quantity allocation plans and annual water allocation plans and inspecting and supervising the implementation of the water allocation plans in the basin; organizing the construction, operation scheduling and management of key water conservancy projects in the basin; coordinating and handling the water disputes among the provinces (autonomous regions) in the basin. Theprovinces (autonomous regions) in the basin shall implement the chief executive accountability system for total quantity control of water consumed, the people's governments at various levels shall, based on the annual water allocation plansformulated by theHeihe Basin Administrative Office of the Yellow River Water Conservancy Committee, be responsible for water consumption and allocation management in the areas under their jurisdiction and adopt comprehensive measures to ensure the realization of the water allocation schemes and various control indicatorsestablished by the State within three years”.