There are many rivers and ravines in rural areas of China, which have the functions of agricultural irrigation, flood storage, climate regulation and pollutant reduction, and are the direct embodiment of water resources and ecological environment benefits. However, with the development of new rural construction, the situation of occupying rivers and discharging pollutants at will is serious, which leads to the decline of water environment quality of rural rivers and the weakening of normal flood control and drainage functions of rivers. Therefore, the management of rural rivers has become an important problem to be solved urgently at this stage, and effective measures need to be taken to improve water quality, increase landscape function, protect water resources and realize comprehensive, coordinated and sustainable development of rural economy and society.
1 characteristics of rural rivers
Rural rivers include rivers within counties or small rivers across counties, as well as smaller drainage and flash flood channels. At present, most of the rivers being treated in the national small and medium-sized river regulation planning belong to rural rivers. Compared with urban rivers, rural rivers have their own functions and characteristics. 1. 1 Functional Diversity The rural river network is the most basic part of the river network, and it is closely distributed. Rural rivers play an important role in rural water conservancy projects. It is not only the main channel for irrigation and drainage, but also an important corridor for water storage and flood regulation, and an important part of landscape ecological corridor. Moreover, rural rivers are important resources for people's production and life, and some rivers are drinking water sources in urban and rural areas. Rural rivers provide rich water resources, biological resources and ecological landscape value, creating a good living environment and development conditions for the construction of new countryside. 1.2 Diversity of River Structure Rural rivers are generally divided into two categories: mountain rivers and plain rivers according to different landforms and flow areas. Rivers in mountainous areas flow through mountainous areas with high terrain, with complex plane shape, tortuous rivers, irregular coastline and bed surface, large runoff coefficient, short confluence time and generally large water surface gradient. Plain rivers flow through plain areas with flat terrain and loose soil. The longitudinal slope of the river bed is gentle, the accumulated water area is large, the confluence time is long, and the water surface gradient is generally small. 1.3 Diversity of water environmental problems With the development of social economy, the phenomenon of encroaching on and polluting rivers is increasing day by day. Due to the lack of effective control measures, the water environmental pollution of rural rivers is becoming more and more serious. The deterioration of water environment in rural rivers has both natural factors and human factors. Natural factors include: irregular river section, most of which have not been treated by engineering, which easily leads to bank slope collapse and dangerous operation. Moreover, the basic flow of rural rivers is small, the water area is not wide, the self-purification function of water bodies is poor, and the quality of ecological environment is fragile. Human factors include: enterprises along the river set up sewage outlets at will, and the wastewater in the production process is directly discharged into the river without treatment, which pollutes the surface water and groundwater environment of the river; Generally, only 10% ~ 20% of pesticides and fertilizers used in agricultural production are attached to crops, and the rest are lost to soil and water. Under the action of farmland irrigation and rainfall, these pesticides and fertilizers seep into the ground and pollute the groundwater environment. People only consider their own convenience, dumping a lot of domestic garbage directly into the river, without considering the subsequent environmental pollution problems. All these will lead to the continuous decline of the water environment quality of rural rivers and hinder the rapid development of urban and rural construction.
2 the main problems of rural rivers
Rural rivers are the lifeblood of flood discharge, water diversion, irrigation and solving people's life and industrial and agricultural water use. For a long time, they have played an important role in flood control and drought relief, reducing natural disasters and promoting economic and social development. However, with the development of economy and the influence of human factors, the function of rural rivers is weakened and the water quality is degraded. 2. 1 The awareness of river protection in rural areas in most areas is not strong. Due to the influence of traditional living habits, villagers in many places regard rivers as garbage dumps and discard all kinds of domestic and construction wastes at will, which intensifies river pollution. In addition, in recent years, illegal buildings (structures) often encroach on rivers, making some rivers basically lose their basic ability of irrigation and drainage and flood control. 2.2 River water environment has reached the final bottom line. With the development of social economy, some industrial sewage is directly discharged into rivers without treatment, and its natural purification function is degraded, resulting in serious water pollution. Some rivers are unattended, and aquatic plants, duckweeds, sundries and all kinds of garbage have accumulated in the rivers for a long time, making the rivers messy; It is difficult to implement the river regulation work, and some rivers have been silted for many years, and the water flow has been blocked and almost dried up. 2.3 River cleaning work is not in place. Most rural rivers are in a natural state, and there is basically no cleaning work. Even if there are some places, most of them can't even do basic work, and they don't know enough about river cleaning and lack special management. In addition, due to the fluidity of river flow, it is difficult to distinguish the responsibilities of upstream and downstream and the left and right banks, and it is difficult to change the "water" situation of the river.
3 rural river comprehensive management measures
Implementing comprehensive improvement of rural rivers is not only an urgent requirement for improving water environment, but also an inevitable requirement for overall planning, coordination and sustainability, implementation of urban and rural planning and practice of Scientific Outlook on Development. According to the situation of the river, we should study and formulate comprehensive improvement measures for rural rivers to treat both the symptoms and the root causes. 3.65438+ 3.2 Combined with river regulation and winter irrigation and water conservancy project construction, river dredging will be implemented in turn, and the dredging of main rivers will be completed, and unified planning and implementation will be carried out to solve practical problems such as serious river siltation, poor flood discharge, weakened storage capacity and poor water quality. 3.3 Ecological restoration of rural river water environment plays an important role in rainfall, flood storage, farmland irrigation and ecological environment. In view of the characteristics of wide distribution of water pollution in rural areas, serious non-point source pollution and great difficulty in treatment, the requirements of irrigation and water supply, flood control and drainage, ecological environment and so on are comprehensively considered, with the goal of improving rural water environment and protecting water resources from pollution, combined with the new rural construction plan, and according to different regions and conditions, the treatment plan is scientifically formulated according to local conditions. At present, the main technical measures of water environment restoration are: constructed wetland treatment technology, stable pond technology, biological floating island technology and soil treatment technology. Constructed wetland treatment technology refers to planting aquatic plants with high survival rate, strong water resistance and long growth cycle on the riverbed surface, forming a unique ecosystem, and achieving the purpose of sewage treatment through the degradation and adsorption of aquatic plants. Stabilizing pond technology refers to creating an environment conducive to the co-propagation and growth of fungi and microorganisms, and using oxygen generated by anaerobic function of microorganisms to remove pollutants effectively to the maximum extent. 3.4 Rural river ecological management to coordinate the relationship between rural development and river ecological protection is an important goal pursued by the river management project. While maintaining the original natural form and hydrological characteristics of the river, we should also maintain the harmony between the river landscape and its surrounding environment. According to the characteristics of rural rivers, its ecological management includes ecological revetment design and riverside landscape design. 3.4. 1 Ecological revetment Ecological river revetment is composed of new protective materials and vegetation, which has certain structural strength, can not only reduce water erosion, but also provide a place for the growth and reproduction of animals and plants, and has the ability of self-repair and purification. Revetment can be divided into two categories: non-biological material revetment and plant (biological) revetment The common revetment is: 1) plant revetment. Planting aquatic plants and wetland plants such as reeds and willows on the slope has the characteristics of developed roots and has a good effect on soil and water conservation on the slope. 2) Natural material revetment. Including wooden stakes, bamboo cages, gabions, rockfill (irregular accumulation) revetment, etc. 3) Green ecological concrete slope protection. It consists of sand-free porous concrete, topsoil and water-retaining materials. Compared with ordinary concrete, green eco-concrete has good water permeability and air permeability, provides a good living space for animals and plants, and has the characteristics of short construction period and low project cost. 4) geosynthetics revetment. It has the characteristics of strong erosion resistance and easy survival of aquatic animals, plants and microorganisms, such as three-dimensional geotextile, three-dimensional vegetation net, geotextile bag, geogrid and so on. Abiotic materials with strong hydrophilicity and permeability should be selected for ecological restoration of river banks. 3.4.2 River bank landscape design In the process of river regulation, it is generally believed that widening the river flood discharge and straightening the cross section can improve the flood control and disaster prevention ability of the river, but the requirements for river landscape are often ignored. It is necessary to comprehensively consider the combination of flood control capacity and ecological environment, and ecological environment protection and river dredging should be carried out simultaneously to make the rural river landscape close to the natural landscape.
Rural rivers are not only important water conservancy facilities, but also an important part of ecological environment. The comprehensive improvement of rural rivers is a long-term project, with concept as the cornerstone, planning as the key, technology as the support and management as the guarantee. It is a general trend of urban and rural construction and development, as well as a good opportunity and challenge to strengthen the regulation of rural rivers and restore them to be beautiful, pleasant and full of vitality.
The above are collected and sorted by Zhong Da Consulting Company.
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