Groundwater development guided by the theory of sustainable development is to ensure the sustainable utilization of groundwater resources, which not only requires that there is groundwater to be extracted, but also requires a good ecological environment; not only to ensure that the present generation has groundwater to be extracted, but also to ensure that future generations have high-quality groundwater resources to be utilized; and not only to make the groundwater to meet the current needs of socio-economic development, but also to guarantee the demand for groundwater resources under the condition of sustained and stable development of the social and economic environment. The demand for groundwater resources under the condition of stable development should also be guaranteed.
Preventing groundwater pollution and protecting groundwater resources
Groundwater is the material basis of social and economic development, and the protection and utilization of groundwater resources is a major event related to the long-term development of social and economic development and the survival of future generations. While striving to develop the economy, the protection of the groundwater resources of the Songnen Plain has become a very urgent task, and it is also a way of realizing the social, economic, human and environmental harmony of the Songnen Plain. At the same time, it is also an important measure to realize the coordinated and sustainable development of society, economy, human beings and environment in Songnen Plain. The protection of groundwater resources should be started from all levels of technology, economy and law, so that water conservation and water protection behavior becomes the habit of people's daily life.
Preventing groundwater pollution, first of all, to protect the groundwater recharge source, in essence, is to protect the quality and quantity of groundwater recharge, that is, to block the source of groundwater pollution, wide open the source of groundwater recharge.
The main sources of groundwater pollution are industrial wastewater and waste, domestic sewage garbage, agricultural sewage irrigation and pesticide and fertilizer pollution, the protection of groundwater must prevent these pollutants from polluting groundwater.
(A) to prevent industrial wastewater, waste pollution
Songnen Plain is one of the old industrial areas in Northeast China, industrial wastewater and solid waste emissions, especially in the 1960s to 1970s, the lack of awareness of groundwater protection, industrial waste residues, wastewater discharged everywhere, most of the open piles and direct discharge of wastewater, wastewater treatment rate is low, in the precipitation of the dissolution of filtering, which contains a large number of harmful substances seeped into the ground. Under the action of precipitation dissolution and filtration, a large number of harmful substances contained therein seeped into the ground, thus polluting the groundwater. Especially in cities such as Daqing, Qiqihar and Baicheng, where the thickness of the air-bearing zone is thin, the structure is loose and the permeability is strong, the groundwater is easily polluted by industrial wastewater and waste. Therefore, it is necessary to strengthen the management of industrial solid waste and wastewater discharges, improve the degree of harmless treatment, strict implementation of the national emission standards, the solid waste dumping site to do a good job of seepage control lining, landfill roof and other treatment measures, strictly prohibit arbitrary discharge, arbitrary dumping, to prevent groundwater pollution.
(B) to prevent domestic sewage, domestic garbage pollution
Songnen Plain is a densely populated area, the population density of nearly 200 people/km2, with the improvement of the people's living standards and the accelerated process of urbanization, domestic sewage and domestic garbage, especially urban sewage and garbage is more and more, the pollution of groundwater will become more and more serious. Rural sewage is directly spilled, most of the urban sewage is discharged from the nullahs without treatment, and the drainage canals have become channels for groundwater pollution. Most of the city's domestic garbage is piled up in the open air, landfill only a few large and medium-sized cities such as Changchun, Harbin, most of the small and medium-sized towns do not have landfill treatment, even if the landfill, most of the landfill site did not make impermeable treatment. Therefore, the construction of domestic sewage treatment and underground sewage network should be strengthened to prevent the pollution of groundwater by domestic sewage, and suitable landfill sites or incineration or crushing of domestic garbage should be selected to prevent the pollution of groundwater by sewage and garbage seepage.
(C) to prevent agricultural pollution
Songnen Plain is a more developed agricultural areas, agricultural production of groundwater pollution will become more and more prominent, to prevent agricultural pollution is the next period of time a heavy and far-reaching daunting task. Pesticides, fertilizers on groundwater pollution is a kind of surface pollution, the number of increasing year by year, the use of a wide area, the point of dispersion, not easy to manage, the pollution of groundwater and no good monitoring measures. Especially in the inclined plains in front of the mountains in the west and the low plains in the middle of the country, the groundwater is shallowly buried and easily polluted by pesticides and chemical fertilizers. This investigation found that even in the eastern high plains area where there is a thick distribution of sub-clay in the upper part of the aquifer, the phenomenon of nitrogen exceeding the standard in the groundwater has appeared on a large scale, and the agricultural pollution is seriously affecting the quality of the groundwater, and even making the groundwater undrinkable. Therefore, it is necessary to strengthen the field management of agricultural production, and gradually adopt low-toxicity, easily degradable, low-residue pesticides instead of long-lasting, highly toxic pesticides, and apply less chemical fertilizers and more agricultural fertilizers, in order to prevent pesticides and chemical fertilizers from polluting the groundwater.
(D) to prevent the exploitation of groundwater pollution
Groundwater in addition to pollutants suffered through the permeability of the air-bound belt pollution, into the poor quality of a variety of mining wells is also an important way to pollute groundwater. Mining wells as a channel of pollution, it communicates the aquifer and the ground or other aquifers containing poor quality water between the hydraulic connection, are in use and abandoned wells can become a pipeline of groundwater pollution. In the past 20 years, in the distribution area of multi-layer pressurized water in the low plains, due to the poor water stopping effect of mining wells for pressurized water, the deep pressurized water is polluted by the tampering layer of shallow poor-quality water, and the fluorine, iron and manganese content of the fourth system pressurized water is obviously elevated, and some of them have already exceeded the sanitary standard for drinking water. Therefore, the development of groundwater, must pay attention to the quality of wells, to take strict technical measures to prevent the exploitation of wells themselves cause groundwater pollution.
Two, the rational development of groundwater, groundwater to maintain the sustainable use of water
(a) scientific planning, reasonable wells
Groundwater has its own movement, the cycle of natural laws, development and utilization should be carried out on the basis of scientific planning. According to the amount of recoverable groundwater resources and the amount of mined resources divided into different groundwater mining areas. The over-exploited areas should gradually reduce the amount of exploitation, and the new exploitation should be strictly limited in the balance of extraction and replenishment areas, while the areas with increased exploitation potential should be reasonably arranged with extraction wells according to the hydrogeological conditions, controlling the amount of extraction in a single well, avoiding over-density of wells and over-exploitation, and ensuring the quality of wells, so as to avoid groundwater pollution in the process of exploitation. Different types of groundwater in different geomorphological units, mining technology conditions vary greatly, should be adapted to the local conditions, deep and shallow combination of priority mining diving, cautious mining of pressurized water.
Western mountain tilted plains of the fourth system of diving, water-rich, shallow depth, the depth of wells 10 ~ 40 m, the well distance should not be less than 800 m. The area of precipitation is small, agricultural water consumption, in recent years the Tao'er River and the Hualin River successively cut off the flow of the groundwater recharge has been greatly reduced, and measures should be taken to increase the artificial recharge of groundwater. In addition, the groundwater environment in this area is fragile, the upper part of the aquifer is thin with air-bearing zone, and most of them are sub-sand soil or sand gravel, without good pollution-isolating layer, and groundwater pollution should be prevented. Diving the lower part of the new recent system of pressurized water, good water quality, water abundance, can be used as a backup water source, in the construction of wells mining, to make a good water stop, to prevent groundwater pollution of the scuttling layer.
Central low plains of the fourth system of diving due to the natural poor water quality, only a small portion of the agricultural water and decentralized drinking water. The fourth series of pressurized water as the main mining purpose layer, in the social and economic development plays a huge role. The fourth series of pressurized water is abundant in most areas, easy to mine, mining depth of 40 ~ 100 m, agricultural mining wells should not be less than 1000 m. Residential wells, special attention should be paid to the problem of stopping the water, for the abandoned wells should be done to deal with the closure of the wells. The layer of water has been found to be contaminated by the upper layer of water, fluorine content than before significantly higher, and even exceeded the standard, years of fluorosis and re-emergence of fluorosis, so special attention should be paid to the mining process of groundwater pollution.
Taikang group and Da'an group of pressurized water, water is relatively rich, single well gushing water more than 1000 ~ 3000 m3 / d, but the recharge resources are insufficient, the ability to update the poor, the cloth wells should not be less than 1500 ~ 2000 m. These two layers of pressurized water as a valuable source of prevention of disease and change of water and drinking water, should be treasured, strictly limit the exploitation. In the Songyuan Oilfield, the new village, Erlong water source has formed a mining funnel, the maximum depth of water level drop in the center of the funnel is 25.62 m and 22.88 m, respectively, appropriate measures should be taken to control the amount of mining, and actively seek other sources of water, to maintain a balanced groundwater extraction and replenishment.
Except for the pressurized water basin and river valley area in the eastern high plain, most of the areas are water-scarce, and there are big differences in hydrogeological conditions and groundwater richness, so the reasonable development of groundwater should be different from place to place. Most of the vast rural areas are exploiting the water-poor diving of the fourth system. As this region is a semi-humid climate zone, agricultural water use is relatively small, and the exploitation of rural domestic water is relatively decentralized, with a small amount of single-well exploitation. Industrial and urban domestic water mainly exploited valley diving and cretaceous pressurized water, should be centralized water supply sources for investigation and evaluation, based on the evaluation results of the rational arrangement of mining wells and determine the amount of mining.
(2) the establishment of groundwater extraction and replenishment balance mechanism
Groundwater resources are limited, but also renewable, atmospheric precipitation, surface water, groundwater in the continuous transformation of each other, the amount of groundwater extraction should be limited to groundwater renewal capacity, which must be adjusted to the existing irrational layout of groundwater extraction, follow the cyclic law of groundwater, to maintain a dynamic balance of groundwater extraction and replenishment
Three, strengthen the integrated management, optimize the allocation of water resources
(a) the current situation of water resources distribution of the main problems
1. Uneven spatial and temporal distribution of water resources water resources distribution of time is mainly reflected in the seasonal distribution of precipitation within the year is uneven, with large inter-annual variations. The average annual maximum precipitation is 646.4 mm, the minimum precipitation is 303.01 mm, the inter-annual variation is 2.1 times. Precipitation during the year is mainly concentrated in June to September, with precipitation accounting for more than 70% to 80% of the annual precipitation. In particular, the agricultural spring water demand is large, precipitation accounts for only 10% to 20%, showing the characteristics of spring drought, summer flooding, autumn less, winter dry, and industrial agriculture and residential life water is not compatible.
The uneven spatial distribution of water resources is mainly reflected in the more precipitation in the east, less in the west, from east to west precipitation decreases, the southwest precipitation is the least. With the decrease in precipitation, the climate also changes, from east to west, the climate from semi-humid climate transition to semi-arid climate. The average annual precipitation in the eastern high plains is 500-600 mm, which is a semi-humid climate, while the annual precipitation in the west is between 350-450 mm, which is a semi-arid climate. Evaporation increases from northeast to southwest, with the evaporation in the eastern high plains ranging from 1150 to 1500 mm and in the west from 1150 to 1600 mm.
2. Mismatch between the distribution of water resources and socio-economic patterns
The mismatch between the distribution of water resources and socio-economic patterns is a serious constraint to sustainable economic and social development. The eastern high plains, is to Changchun, Harbin capital city as the center of the city, population, economic intensive belt, there are Dewei, Yushu, Shuangcheng, Suihua, Hailun and other medium-sized cities and economic development zones, the demand for water resources is large, but this area of the groundwater is poor, the pollution of surface water is serious, the contradiction between the supply and demand of water resources is prominent.
The central low plain, is an important agricultural and animal husbandry production base and energy and chemical industry base, but also the national ecological agriculture construction area, where there are the famous Zalong wetland, Momog wetland, more lake bubbles and swamps, agriculture and ecological water use is larger, the groundwater resources are relatively rich, but the precipitation is small, evaporation, shallow groundwater water quality is poor, the land is salinization, sanding is serious, the fragile ecological environment, the environmental issues Outstanding. Groundwater is the main source of water for the socio-economic development of the region, the demand for water resources has been greater than the total amount of water resources, deep groundwater is being continuously exploited and utilized, and there has been a regional decline in groundwater level due to irrational exploitation of groundwater, which has triggered a series of ecological and environmental problems and aggravated the contradiction between the economic water use and ecological water use.
The western pre-mountain sloping plains are relatively rich in groundwater, but socio-economic development is relatively backward and the ecological environment is fragile. Groundwater recharge from the rivers of the Daxinganling accounts for a large proportion of groundwater, and in recent years, due to low precipitation, increased agricultural exploitation, reduced river runoff, groundwater recharge is insufficient, and the water level appears to be a continuing downward trend.
(2) the way to optimize the allocation of water resources
1. Priority development and utilization of surface water, the rational use of water in transit
The total water resources of Songnen Plain is 175.16 × 108m3, of which surface water accounts for 55.3%, and non-repeatable groundwater accounts for 44.7%. Priority development and utilization of surface water should be the key point in the optimal allocation of water resources, especially in the eastern part. High plains, poor groundwater storage conditions, precipitation resources are relatively more, more should be the development of surface water resources in the first place.
Optimizing surface water should be carried out from time and space. Time optimization is the use of reservoirs, lakes, wetlands, ponds and dams to intercept the amount of surface water during flood season, regulating river runoff, improve the inter-annual variability of natural runoff and seasonal distribution within the year uneven problem. Spatial optimization is based on scientific evidence, through water diversion projects and water transfer projects to regulate the spatial distribution pattern of water resources, so that the allocation of water resources to better meet the needs of economic and social development and ecological environment. Songnen Plain is rich in transit water resources, the region's average annual inbound water volume of 383.2 × 108m3, and good water quality, the outbound water volume of 481.63 × 108m3, surface water out of the Three River Plain into the Heilongjiang River, the downstream of the socio-economic density is small, water resources, the use of transit water will not produce with the downstream of the competition for water or impact on the ecological environment and other issues.
2. Joint scheduling of surface water and groundwater
Joint scheduling of surface water and groundwater is an important measure in the allocation of water resources, especially in the western part of the Songnen Plain, where there are a number of alluvial fans and huge groundwater storage space, which is a natural groundwater reservoir, and it is very suitable for utilizing the underground space for the storage of groundwater and surface water and the artificial replenishment of groundwater can be carried out by utilizing the flood water during the water-abundant period or water-abundant year. Floods can be used to artificially recharge groundwater, or water conservancy hub projects can be used to artificially recharge groundwater, leaving it to be utilized in the dry season or dry year, which can not only reduce the harm of floods, but also increase the recharge of groundwater. The alluvial fan in front of the mountain is not only a good storage space for groundwater, but also an important recharge zone for groundwater in the central low plains, ensuring a high groundwater level in front of the mountain can increase the recharge of groundwater in the central low plains. In addition, in the valley of the Nenjiang River, the Second Songhua River and its larger tributaries, there is a large space for groundwater storage, which allows for the joint storage of surface water and groundwater.
3. Sub-water quality water supply, the development and utilization of a variety of water sources
Sub-water quality water supply is also an important measure for the rational allocation of water resources, sub-water quality water supply should be prioritized to ensure the safety of drinking water, to ensure that high-quality groundwater for drinking water. Sub-water quality water supply should follow the principle of superior water, quality and price, the water quality requirements of agriculture and other water, as far as possible to minimize the exploitation of high-quality groundwater. In the process of water resources utilization, the allocation of drinking water, miscellaneous water for living, industrial water, agricultural water, municipal water, service water, ecological environment water, etc. should be rationalized according to the specific situation. At the same time in the sub-quality water supply, should also actively develop and utilize a variety of water sources, such as artificial rain, transformation of brackish water, water reuse, etc., to increase the development of a variety of water inputs, improve the development and utilization of a variety of water sources.
4. Scientific arrangement of ecological water
Predatory exploitation of water resources, the Songnen Plain ecological environment caused by the damage is huge, the lesson is profound. Rational arrangement of production, living, ecological water, is one of the basic principles of rational allocation of water resources, is the implementation of the scientific concept of development and the concept of harmony between man and water is a concrete embodiment. Through administrative, economic, technical, engineering and other comprehensive measures, scientific arrangement of lakes and wetlands in the low plains area water use, and constantly increase the ecological water replenishment and ecological restoration efforts, the establishment of ecological water use of the normalization mechanism, and effectively guarantee the long-term water use of the ecological environment.
5. Strengthen the integrated management of water resources, the establishment of a sound social system for the optimal allocation of water resources
The Songnen Plain is a cross-provincial river basin water resources system, in order to achieve the optimal allocation of water resources, it is necessary to establish a national level of effective integrated water resources optimization and allocation of water resources management institutions, from the macro and micro multi-level face of water resources to the rational allocation. From integrated water resources planning to a sound legal system of water rights, as well as a systematic management indicator system and the development of water supply and demand market, all need to be further improved, cultivated and strengthened.
Four, people-oriented, to protect the safety of drinking water
Water is the source of life, is a natural resource on which mankind relies for survival, but also people's daily life is irreplaceable means of subsistence. Adhere to the people-oriented, to protect the people's drinking water safety is the comprehensive construction of a well-off society, harmonious society, improve the quality of life of the people a top priority.
(a) the main measures to ensure the safety of rural drinking water
As mentioned earlier, in the Songnen Plain in the vast rural areas, drinking water is basically all the use of groundwater, the widespread distribution of poor-quality water and the increasingly serious situation of pollution and localized areas of resource depletion, increasing the rural drinking water safety hazards, and the water quality of the hazards greater than the amount of water hazards. Eliminate rural drinking water safety hazards, is to eliminate the impact of rural drinking water insecurity factors, mainly in the following areas:
1. Improve the quality of drinking water
Songnen Plain large areas of the distribution of high fluoride, high arsenic poor quality groundwater, is an important factor affecting the safety of rural drinking water. In this regard, we should actively seek high-quality water sources, the use of engineering measures to improve the quality of drinking water to prevent the occurrence of drinking water-type endemic diseases.
2. Repair of contaminated groundwater
The increase in the degree of agricultural pollution has been a threat to rural drinking water safety. The high plains dive is the main source of rural drinking water, there has been a large area of exceeding the standard, pesticides have also been detected in the groundwater, most of the rural areas in addition to groundwater, there is no surface water available, should actively take measures to prevent the spread of agricultural pollution, and increase the research of groundwater pollution remediation technology investment, has been contaminated groundwater integrated remediation and management.
3. Concentrated treatment of rural living garbage
With the complexity and diversification of the composition of daily consumer goods and the increasing number, the harmful components of rural living garbage are also more and more, and the contamination of groundwater by these harmful components will be a potential factor affecting the safety of rural drinking water. At present, rural sewage is discharged at will, and domestic garbage is piled up at will, there is no centralized dumping place, not to mention the centralized treatment facilities, and it seeps into the ground under precipitation, which will definitely affect the safety of drinking water in rural areas in the long term, and while building the new socialist countryside, the treatment of rural sewage and domestic garbage should be included in the overall planning of the construction of the new countryside.
4. Protecting the middle and deep pressurized aquifer in the low plains area
The middle and deep pressurized water in the low plains area is a good source of water for local rural production and life, and also the water supply purpose layer for rural disease prevention and water reform, the water of this layer in the process of mining by the contamination of the upper layer of poor-quality dive, and the water quality declined, and in the long run it will certainly affect the safety of the drinking water of the rural areas in the low plains area. In addition, the prevention of oilfield pollution is also an important aspect of ensuring the safety of rural drinking water in the low plains area.
5. Promote water conservation, and actively seek new water sources
Part of the rural areas, groundwater resources are poor, over-exploitation leads to the reduction of groundwater resources, water supply sources are insufficient, drinking water supply rate declined, the emergence of a shortage of water-type drinking water safety problems. These areas should use a variety of means to promote water conservation, while actively looking for new sources of water supply.
(2) the main measures to ensure the safety of urban water supply
1. unified management, scientific planning
city water supply safety must be integrated into the overall urban planning, give full consideration to local water resources conditions, scientific development of urban water resources planning and urban water supply safety prevention mechanism, rational allocation of groundwater and surface water supply sources, the establishment of engineering measures and non-engineering measures to ensure the safety of urban water supply system. The urban water supply security system of engineering measures and non-engineering measures.
2. Strengthen monitoring and establish early warning mechanism for urban water supply safety
Apply all kinds of high and new technology and equipment, constantly improve the monitoring level of groundwater and surface water, and establish early warning mechanism for urban water supply quality and quantity, so as to prevent problems before they occur.
3. Construction of water-saving city
In the long run, urban water shortage will be a common phenomenon, to ensure the safety of urban water supply, must build water-saving city, the use of administrative, legal, economic, technical and other comprehensive measures to promote water conservation, improve water use efficiency, to ensure the balance of water supply and demand.
4. Establish and improve the urban water supply emergency mechanism
To ensure the safety of urban water supply, we must prepare the urban water supply emergency plan, on the basis of water resources evaluation, combined with the rational allocation of urban water resources and water supply process of the existence of safety hazards and other factors, the establishment of the urban water supply emergency mechanism, and practical exercises, into the overall planning of urban development.
V. Developing water-saving agriculture and guaranteeing food security
(A) vigorously promoting water-saving irrigation technology
In the 1970s, the world witnessed a serious food crisis, and the Food and Agriculture Organization of the United Nations (FAO) issued a warning on food security to all governments. Food security can be summarized as the availability of food that is necessary for health, structurally sound and nutritionally adequate at all times and under all circumstances. As we all know, irrigation can guarantee food production, agriculture is the industry that uses the most water, agricultural water consumption in Songnen Plain has accounted for 78% of the total water consumption in the whole region, of which groundwater accounts for 54.55% of the agricultural water consumption, and the irrigated area for agriculture is still expanding, and the agricultural water consumption of Songnen Plain will reach 46×l08m3 in 2010, and 58×108m3 in 2020, and the lack of water has become an important factor that constrains food production. Constraints on food production is an important factor, water-saving irrigation is to ensure the security of food production is the only way. Popularize agricultural water-saving irrigation technology, improve the efficiency of agricultural water use, guarantee the quality of agricultural irrigation water, is one of the basic ways to ensure food security.
(2) rational development of paddy fields, dry land surface watering area
Water diversion irrigation, undoubtedly can increase the recharge of groundwater, accelerate the circulation of groundwater, especially paddy fields, because they are mostly planted on terraces, rambling beach, water diversion irrigation, there will be 30% to 40% of the surface water seepage into the ground, recharge groundwater. However, the large-scale development of paddy fields and excessive diversion of water will also cause a reduction in river runoff, damage the ecological health of the river system, or even lead to river breakage, which not only affects the amount of river recharge to groundwater, but also affects the ecological environment water use and water use in other sectors.
Sixth, the development of water-saving economy, the comprehensive construction of water-saving society
Water-saving society is a comprehensive establishment of water-saving consciousness, the establishment of water-saving economic structure, lifestyle, mode of production, and water resources management system and mechanism, in order to efficiently use water to ensure the sustainable development of socio-economic and ecological environment of the resource-saving and environmentally friendly socio-economic system, the development of water-saving economy is an important part of the construction of the water-saving society. The development of a water-saving economy is an important part of building a water-saving society.
With the increase of population, rapid economic development and urbanization level, the demand for water continues to increase, while the amount of underground water resources is limited, uneven distribution, theoretically calculated, by 2020 the Songnen Plain groundwater demand will reach the amount of groundwater can be extracted, but in practice the amount of groundwater can never be extracted out, so water shortage is bound to come early, water shortage is an inevitable trend, relying on the expansion of water supply to solve the water shortage crisis is not possible. Expanding the water supply to solve the water shortage crisis is unsustainable, water conservation is the fundamental way out to deal with the water shortage crisis.
Songnen Plain agricultural water accounted for 78% of the region's water consumption, including the use of groundwater accounted for 73% of the amount of groundwater extraction, irrigation methods, irrigation water utilization rate is low, agricultural water saving potential is huge.
Industrial water consumption accounted for 5.44% of the total water consumption in the region, groundwater accounted for 66.85% of industrial water consumption, and 118 m3 of groundwater was consumed by 10,000 yuan of GDP. In the low plain area, almost all of the industrial water comes from groundwater, and with the implementation of the strategy of revitalizing the old industrial base in Northeast China, the amount of water demanded by the industry is bound to increase, and thus the industrial water should be rationally allocated according to the local water resources conditions, optimize the industrial structure, and develop water-saving industries. Industrial structure, the development of water-saving industry, increase sewage treatment, the construction of water reuse projects to improve the water reuse rate.
Adopting a lifestyle and habits compatible with a water-saving society, popularizing water-saving knowledge through water-saving publicity and education, and enhancing people's awareness of water conservation is the foundation work for the comprehensive construction of a water-saving society.