Underground water unified station network system

Abstract

The invention relates to an underground water unified station network system which comprises underground water monitoring station horizon unified division and subarea station network system construction. The underground water monitoring station horizon uniform division comprises the steps that a water conservancy station, a provincial station and a natural resource station establish a layering and zoning uniform evaluation station network system according to an aquifer group bottom plate elevation contour line, a typical hydrogeological section and typical hydrogeological drill holes, and underground water monitoring points in a region are divided to the corresponding hydrogeological section according to the nearest distance principle; according to the subarea station network system, points, lines and planes are selected in a delimited evaluation unit, representative stations with a plurality of aquifer groups in the evaluation unit should be selected in a layered mode, the representative stations comprise an overdraft area evaluation station network, a river and lake water replenishing area evaluation station network and a sea / salt water invasion area evaluation station network, and dynamic water level analysis evaluation is formed. According to the invention, the underground water monitoring station network is divided into layers and groups in a unified standard at a watershed level for the first time, a unified watershed station network system is constructed, and accurate monitoring, accurate evaluation and fine management are strived.

Description

Technical Field

[0001] The present invention relates to the technical field of basin groundwater monitoring, and in particular to a groundwater unified station network system. Background Art

[0002] Groundwater has important resource supply and ecological maintenance functions and plays an irreplaceable role. The scale of groundwater development and utilization has been continuously expanded. In some areas, groundwater has been over-exploited, resulting in the nearly drying up of aquifers and causing a series of serious environmental geological problems such as ground subsidence, ground collapse and ground fissures, sea (salt) water intrusion, and land desertification.

[0003] At present, there is no unified division of groundwater monitoring layers in the basin, and the evaluation results vary greatly, making it difficult to achieve refined stratified management. Summary of the invention

[0004] The present invention aims to solve the deficiencies of the prior art and provide a unified groundwater station network system.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A unified groundwater station network system, including unified division of groundwater monitoring stations and construction of a zoned station network system;

[0007] The unified division of groundwater monitoring stations is that water conservancy stations, provincial stations and natural resources stations establish a unified evaluation station network system based on the elevation contour lines of the bottom plate of the aquifer group, typical hydrogeological profiles and typical hydrogeological boreholes. The groundwater monitoring points in the region are divided into the corresponding hydrogeological profiles according to the principle of the closest distance; the plain area is divided into a single-layer structure area and a multi-layer structure area. The multi-layer structure area is divided into four aquifer groups from top to bottom. The bottom interface of the first aquifer group is buried at a depth of 10-50m, the bottom interface of the second aquifer group is buried at a depth of 120-210m, the bottom boundary of the third aquifer group is buried at a depth of 250-310m, and the bottom boundary of the fourth aquifer group is to the bottom boundary of the research depth; the water-bearing media in the hilly area are divided into three types, including loose rock porous water aquifer groups in intermountain basins, carbonate rock karst aquifer groups and fracture porous water aquifer groups;

[0008] The regional station network system is selected by combining points, lines and surfaces within the defined evaluation unit. If there are multiple aquifer groups in the evaluation unit, the representative stations should be selected in layers, including the over-exploitation area evaluation station network, the river and lake water replenishment area evaluation station network and the sea saltwater intrusion area evaluation station network, to form a dynamic analysis and evaluation of water level; the over-exploitation area evaluation station network includes the shallow over-exploitation area, the deep over-exploitation area and the funnel area, and the sea / saltwater intrusion area evaluation station network is based on TDS and Cl - The evaluation indicators of sea / saltwater intrusion status are divided into seawater intrusion area and saltwater distribution area.

[0009] Based on the contour maps of the bottom elevations of different aquifer groups within the region, the monitoring layers where the groundwater monitoring stations are located are uniformly divided, and then the typical hydrogeological profiles in the region are used to verify the monitoring layers. In areas where the profiles are sparsely distributed, the hydrogeological boreholes in the region are collected, and the aquifer characteristics of the boreholes are further used to divide the hydrogeological conditions of the groundwater monitoring wells. The groundwater monitoring points in the region are divided into their respective hydrogeological profiles based on the principle of the closest distance.

[0010] When selecting a station network in a groundwater overexploitation area, all monitoring stations within the overexploitation area and near its boundaries should be selected as representative stations based on the actual distribution of the station network.

[0011] When selecting a station network in a groundwater funnel area, the evaluation unit should be determined with the goal of understanding the changes in the elements of the groundwater drawdown funnel. Representative stations should be selected in the center area, transition area, and edge area of ​​the funnel in a cross or cross shape. The production well should be selected as the representative station in the center area of ​​the funnel.

[0012] A station network is selected in the river and lake ecological water replenishment area, and representative stations are selected symmetrically in the four directions of the lake shape. Shallow stations are mainly selected to reflect the changes in shallow groundwater levels, and some deep stations are selected to compare and analyze the hydraulic connection between deep and shallow layers or to indirectly reflect the changes in groundwater extraction.

[0013] When selecting a station network in seawater intrusion areas and salt water distribution areas, representative stations should be selected in coastal plain areas, near inland salt lakes or salt ponds, and in areas where fresh and salt water alternately distribute, along the groundwater flow direction, vertically on the shore, or at the interface between fresh and salt water.

[0014] In areas where intensive exploitation of deep groundwater has caused the upper layer of water to move downward, representative stations should be selected in accordance with the principle of selecting as many as possible.

[0015] The beneficial effects of the present invention are: for the first time, the present invention divides the groundwater monitoring station network into layers according to unified standards at the river basin level, constructs a unified station network system for the river basin, strives for accurate monitoring, precise evaluation and meticulous management; and proposes different types of regional evaluation station networks for river basin plain areas, over-exploited areas, river and lake water replenishment areas and saltwater intrusion areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the principle of the present invention;

[0017] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. The present invention is described in more detail by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0021] A unified groundwater station network system, such as Figure 1 As shown, it includes the unified division of groundwater monitoring stations and the construction of a zoned station network system.

[0022] The unified division of groundwater monitoring stations is that water conservancy stations, provincial stations and natural resources stations establish a unified evaluation station network system based on the elevation contour lines of the bottom plate of the aquifer group, typical hydrogeological profiles and typical hydrogeological boreholes. The groundwater monitoring points in the region are divided into the corresponding hydrogeological profiles according to the principle of the closest distance; the plain area is divided into a single-layer structure area and a multi-layer structure area. The multi-layer structure area is divided into four aquifer groups from top to bottom. The bottom interface of the first aquifer group is buried at a depth of 10-50m, the bottom interface of the second aquifer group is buried at a depth of 120-210m, the bottom boundary of the third aquifer group is buried at a depth of 250-310m, and the bottom boundary of the fourth aquifer group is to the bottom boundary of the research depth; the water-bearing media in the hilly area are divided into three types, including loose rock porous water aquifer groups in mountain basins, carbonate rock karst aquifer groups and fissure porous water aquifer groups.

[0023] The regional station network system is selected by combining points, lines and surfaces within the defined evaluation unit. If there are multiple aquifer groups in the evaluation unit, the representative stations should be selected in layers, including the over-exploitation area evaluation station network, the river and lake water replenishment area evaluation station network and the sea saltwater intrusion area evaluation station network, to form a dynamic analysis and evaluation of water level; the over-exploitation area evaluation station network includes the shallow over-exploitation area, the deep over-exploitation area and the funnel area, and the sea / saltwater intrusion area evaluation station network is based on TDS and Cl -1 The evaluation indicators of sea / saltwater intrusion status are divided into seawater intrusion area and saltwater distribution area. Specific embodiment:

[0025] This embodiment takes the North China Plain and the Haihe River as examples.

[0026] 1. Unified division of groundwater monitoring stations

[0027] 1. Aquifer distribution characteristics

[0028] (1) Distribution characteristics of aquifers in plain areas

[0029] The water-bearing medium in the plain area is mainly loose rock porous water aquifers. Based on the geological structure characteristics of the North China Plain, the North China Plain is divided into single-layer structure areas and multi-layer structure areas. The single-layer structure area is mainly distributed at the top of the piedmont plain. The rock particles are coarse, and the clay soil is mostly distributed in a lens shape. The upper and lower hydraulic connections are good, forming a single-layer hydrogeological structure. The multi-layer structure area is distributed at the bottom of the piedmont plain, the central plain, and the coastal plain area. Sand layers and clay layers are distributed alternately. According to the division principle of the Quaternary aquifer group, the Quaternary aquifer system is divided into four aquifer groups from top to bottom.

[0030] The bottom interface of the first aquifer group is buried at a depth of 10-50m, and is an active circulation and alternation layer of groundwater; this layer is of little significance to the development and utilization of groundwater, but plays an important role in the research and protection of the ecological environment. The bottom interface of the second aquifer group is generally buried at a depth of 120-210m, which belongs to slightly pressurized and semi-pressurized groundwater, with strong groundwater circulation and alternation capabilities. It is the main groundwater exploitation layer for agricultural water use in the area. The bottom boundary of the third aquifer group is generally buried at a depth of 250-310m, and is currently the main exploitation layer for deep confined groundwater. The bottom boundary of the fourth aquifer group is to the bottom boundary of the depth of this study, and this layer is partially exploited in the coastal plain.

[0031] ① Aquifer Group I

[0032] The bottom interface of the first aquifer group is generally buried less than 50m deep. In the frontal zone and the alluvial fans in front of the mountain, the aquifer thickness decreases, the particle size becomes finer, and it presents a thin-layered multi-layer aquifer structure. There are clay layers of varying thickness between the aquifers. The permeability and conductivity of the aquifer deteriorate significantly, and the conductivity coefficient is mostly 100-500m. 2 / d, the unit water inflow is usually 5-10m 3 / (h·m), the groundwater recharge conditions also deteriorate. In the Fanqian depression area, the aquifer is composed of silt sand, the thickness is mostly less than 10m, and the hydraulic conductivity is generally less than 100m 2 / d, unit water inflow is less than 5m 3 / (h·m), developing salt water with TDS5-10gL.

[0033] In the ancient river channel belt area of ​​the central plain, it is a strip-shaped aquifer, mainly composed of silt and fine sand, with a general thickness of 10-30m and a hydraulic conductivity of 100-300m. 2 / d, unit water inflow is 5-10m 3 / (h·m). In the main river channel, the aquifers are mostly single-layer or double-layer structures, and the overlying strata are highly permeable, which is conducive to the infiltration of precipitation. The hydraulic properties of groundwater are phreatic-slightly confined water, and the water quality structure is "fresh-salty" type.

[0034] In the coastal plain, the aquifer is mainly composed of silt and fine sand, with a thickness of generally less than 10m, and 10-20m in some areas. In southern Tianjin and south of it, the aquifer has a conductivity of 10-50m 2 / d, the unit water inflow is usually less than 2.5m 3 / (h·m), mostly covered with clay or sandy clay, poor precipitation infiltration recharge, groundwater has obvious pressure-bearing capacity, strong evaporation is accompanied by the influence of marine transgression, and the TDS of groundwater is mostly greater than 5g / L.

[0035] ② Aquifer Group II

[0036] The bottom interface is generally buried at a depth of 120-210m. In the piedmont plain and the central plain of Henan Province, it has a good hydraulic connection with the first aquifer group. From west to east, 2-3 sets of medium-fine sand-medium-coarse sand-sand-gravel rhythmic layers are developed, and the permeability and conductivity of the aquifer are stronger than those of the first aquifer group.

[0037] In the central plain, the aquifer is mainly composed of medium-fine sand and fine sand formed by river alluvial action and lake sedimentation. The permeability and conductivity are significantly weaker than those in front of the mountain. The water yield of a single well is 5-10m 3 / (h·m), clay or sandy clay is generally developed between the aquifer group I, and the groundwater recharge is weak. The fresh water in the lower part of the aquifer group II is an important source of water for industrial and agricultural production.

[0038] In the coastal plain, the aquifer is mainly composed of silt and fine sand. Due to the influence of the late Middle Pleistocene marine transgression, four marine transgression layers are generally developed. The water quality is saline water in the upper part, which is continuous with the saline water of the first aquifer group, and fresh water in the lower part.

[0039] ③ Aquifer Group III

[0040] The bottom boundary of the III aquifer group is buried at a depth of 250-310m. Except for local depressions and coastal areas, it is generally fresh water.

[0041] The aquifers in the piedmont plain are fan-shaped and fan-group-shaped, and consist of 3-4 sets of medium-fine sand, medium-coarse sand, and gravel. The lower aquifers have suffered varying degrees of weathering. To the north of Shijiazhuang, the water yield of a single well in the fan is 20-50m 3 / (h·m), the water yield of a single well in the inter-fan zone is 10-20m 3 / (h·m), the III aquifer group in the foothills south of Shijiazhuang is thin, discontinuous, and contains more muddy gravel layers, with weak water-richness. In general areas, the single well yield is 5-10m 3 / (h·m).

[0042] In the central plain, the aquifer is distributed in tongue and belt shape, and is composed of 3-4 sets of fine sand and medium sand. Compared with the II aquifer group, it has coarser grain size, better sorting, thicker single layer, stronger water conductivity, and the water yield of a single well is 5-15m 3 / (h·m).

[0043] In the coastal plain, the aquifer is mainly composed of silt and fine sand, and the water-richness, water conductivity and recharge conditions are worse than those in the central plain. The water yield of a single well is generally 5-10m 3 / (h·m), slightly smaller in some places.

[0044] ④ Aquifer Group IV

[0045] The bottom boundary of the IV aquifer group is the Quaternary basement. The hydraulic properties of the groundwater in this layer are all confined water. The TDS is slightly higher than that of the III aquifer group. Except for the coastal plain area where it reaches about 2gL, other areas are less than 2gL.

[0046] The alluvial fan in front of the mountain is composed of 3-4 sets of medium-fine sand and gravelly medium-coarse sand rhythms formed by alluvial, diluvial, lacustrine and glacial-glacial water accumulation. There are thick clay layers between the aquifer groups and between them and the third aquifer group, and the vertical and lateral recharge conditions are poor.

[0047] In the central plain and coastal plain areas, the aquifers are mainly composed of medium-fine sand and fine sand, which are deposited alternately by thick layers of clay, silty clay and water-bearing sand layers. The weathering and cementation degree is high, and the permeability and water-richness are weak. The unit yield of a single well is 5-10m 3 / (h·m) and 2.5-5.0m 3 / (h·m) is mainly used.

[0048] (2) Distribution characteristics of aquifers in mountainous areas

[0049] The water-bearing media in mountainous areas can be divided into three types, including the loose rock pore water aquifer group in intermountain basins, the carbonate rock karst aquifer group and the fissure pore water aquifer group.

[0050] ① Loose rock pore water aquifer group in intermountain basin

[0051] It is mainly distributed in Datong Basin, Xinzhou Basin and Changzhi Basin in Shanxi Province, and is mainly composed of loose rock porous water-bearing rock groups. The main water-taking layer is 200m or shallower. It is generally believed that 50m is shallow groundwater, 50-200 is medium-deep layer, and more than 200m is basically unused. The difference between intermountain basins and plain areas is that the continuity of the impermeable layer is poor, and the aquifers are mostly lenses, because the specific aquifer groups are no longer distinguished, only the deep and shallow layers are distinguished.

[0052] ② Fracture pore water-bearing rock group

[0053] Clastic rock fissure pore water is mainly distributed in the Yangquan-Yuci-Tunliu County area of ​​Shanxi Province, the Shuozhou City-Datong City area of ​​Shanxi Province, the Chicheng County-Xuanhua area of ​​Zhangjiakou City, the Xinghe County area of ​​Inner Mongolia Autonomous Region, and the Chengde City-Pingquan County area. Among them, the Yangquan-Yuci-Tunliu County area has a distribution area of ​​10,880 km 2 The water-rich properties of the fissures and pores of clastic rocks are extremely weak; the distribution area is 4000km from Shuozhou City to Datong City. 2 The water-richness of the cracks and pores in clastic rocks is weak, and the groundwater runoff modulus is 1.6-2.3L / s·km 2 ; Chicheng County-Xuanhua area of ​​Zhangjiakou City, with a distribution area of ​​2400km 2 , clastic rock fissure pores are moderately water-rich; Xinghe County, Inner Mongolia Autonomous Region, with a distribution area of ​​2500km 2 The pore water in the clastic rock is rich; in the Chengde City-Pingquan County area, the distribution area is 3200km 2 , the pores in the fissures of clastic rocks are highly water-rich. The water-bearing groups in the fissures of magmatic rocks are divided into the fissure water-bearing groups of intrusive rocks and the fissure water-bearing groups of extrusive rocks. Among them, the fissure water-bearing groups of intrusive rocks are mainly distributed in the Yanshan Mountains, the Fengxian Manchu Autonomous Region-Pingquan County area, and the Qinglong Manchu Autonomous County area. The distribution area in the Fengxian Manchu Autonomous Region-Pingquan County area is 5400km 2 , the water-rich degree is weak; the distribution area in Qinglong Manchu Autonomous County is 2100km 2 The water-rich degree of the eruptive rock fissure water-bearing group is widely distributed in the Yanshan Mountains, Duolun County of Inner Mongolia Autonomous Region, and Weichang Manchu Administrative Area of ​​Chengde City, with a distribution area of ​​17,200 km 2 The second largest area is Lingyuan City, Liaoning Province, with an area of ​​1800km 2 , the water-rich degree is weak. Metamorphic rock fissure water-bearing groups are widely distributed in the Yanshan Mountains, mainly in Zhangjiakou Shangyi County-Fengning Manchu Autonomous Region, Beijing Pinggu County East-Qianxi County, Hebei Province Fuping County-Pingshan County, Zanhuang County-Xingtai County, Shanxi Province Hunyuan County-Fanshi County-Yu County North. Zhangjiakou Shangyi County-Fengning Manchu Autonomous Region has a distribution area of ​​more than 10,000 km2, with weak water-richness, and Beijing Pinggu County East-Qianxi County has a distribution area of ​​2,800 km 2 , but weak in water-richness; the distribution area in Fuping County-Pingshan County, Hebei Province is 6600km 2 , but weak in water-richness; the distribution area in the Zanhuang County-Xingtai County area is 3000km 2 , rich in water but weak in quality; in the area of ​​Hunyuan County, Fanshi County, and the north of Yu County, Shanxi Province, with a distribution area of ​​7600km 2 , the water-richness is extremely weak.

[0054] ③Carbonate rock fissure karst water-bearing rock group

[0055] It is mainly distributed in the southern section, middle and northern section of Taihang Mountain and the southern area of ​​Yanshan Mountain in Hebei Province, including Baiquan Spring Area, Heilongdong Spring Area, Yimu Spring Area, Laiyuan Spring Area, Weizhou Spring Area, Shigu Spring Area and Dongfeng Lake Spring Area, covering an area of ​​about 12,900 km 2 Carbonate rock fissure karst water-bearing rock groups are also distributed in Bo'ai County-Pingshun County of Henan Province, the northern part of Shuozhou City of Shanxi Province, Hunyuan County of Shanxi Province, and Lingchuan County-Licheng County.

[0056] 2. Stratum division method and results

[0057] Based on the contour maps of the floor elevations of different aquifer groups in the North China Plain, the monitoring layers of the groundwater monitoring stations in the plain area are uniformly divided. The monitoring layers are then verified using 30 typical hydrogeological profiles in the North China Plain. In areas where the profiles are sparsely distributed, hydrogeological boreholes in the plain are collected, and the aquifer characteristics of the boreholes are further used to divide the hydrogeological conditions of the groundwater monitoring wells.

[0058] The shallow groundwater system in the North China Plain is the aquifer group I and II in the piedmont plain, and the aquifer group I in the central plain and coastal plain. The deep groundwater system is the aquifer group III in the piedmont plain, and the aquifer groups II and III in the central plain and coastal plain. According to the classification standard of shallow and deep groundwater, there are 2,158 shallow groundwater monitoring stations and 3,371 deep groundwater monitoring stations.

[0059] The groundwater monitoring points in the plain area are divided into the hydrogeological profiles according to the principle of the closest distance. According to the collected groundwater monitoring well depth information, the aquifer group where each well is located is read. In this way, the information of the groundwater monitoring wells closest to the profile is read one by one. In places where the distribution of some profiles is relatively sparse, the monitoring layer is read according to the nearby hydrogeological boreholes.

[0060] According to the above principles, 5935 groundwater monitoring points in the plain area are divided into four aquifers, including 1079 sites for monitoring aquifer group I, 2084 sites for aquifer group II, 1350 sites for aquifer group III, and 401 sites for aquifer group IV. In addition, 381 sites are for mixed layer monitoring, 97 sites are for fissure water and karst water, and 542 sites lack well data and cannot determine the monitoring layer.

[0061] According to the characteristics of groundwater aquifer groups in plain areas and mountainous areas, the specific aquifer groups and groundwater types monitored by groundwater monitoring stations in plain areas and mountainous areas within the Haihe River Basin are classified.

[0062] 2. Construction and application of regional station network system

[0063] 1. Principles for selecting station networks

[0064] The representative stations for water level evaluation should be selected in combination with points, lines and surfaces within the designated evaluation unit. If there are multiple aquifer groups within the evaluation unit, the representative stations should be selected in layers. The principles for selecting station networks are different for over-exploited areas, funnel areas, seawater intrusion areas, saltwater distribution areas, and river and lake ecological water replenishment areas. When selecting station networks in groundwater over-exploited areas, all monitoring stations within and near the boundaries of the over-exploited areas should be selected as representative stations based on the actual distribution of the station network. When selecting station networks in groundwater funnel areas, the evaluation unit should be determined with the purpose of mastering the changes in the elements of the groundwater drop funnel. Representative stations should be selected in the center area, transition area, and edge area of ​​the funnel in a cross shape. The mining well can be selected as the representative station in the center area of ​​the funnel. When selecting station networks in river and lake ecological water replenishment areas, representative stations should be selected symmetrically in four directions according to the shape of the lake (wetland). Shallow stations should be mainly used to reflect the changes in shallow groundwater levels, and some deep stations should be selected to compare and analyze the hydraulic connection between deep and shallow layers or to reflect the changes in groundwater extraction volume. When selecting station networks in seawater intrusion areas and salt water distribution areas, representative stations should be selected in coastal plains, near inland salt lakes or salt ponds, and in areas where fresh and salt water alternate, along the groundwater flow direction, vertically along the shore or at the interface between fresh and salt water. In areas where intensive exploitation of deep groundwater has caused the upper layer of water to move downward, representative stations should be selected in accordance with the principle of selecting as many as possible.

[0065] 2. Overexploitation area assessment station network

[0066] The station network selection in the over-exploitation area is based on the principle of "selecting as many as possible", including 2717 national stations, 2400 local stations, and a shallow station network density of 33 stations / 1000km 2 The density of deep-seated stations is 23 / 1000km. 2 Using the results of the new round of overexploitation zone delineation in the Haihe River Basin, 1,336 monitoring sites in the shallow groundwater overexploitation zone, 134 points in the shallow groundwater overexploitation critical zone, 2,075 monitoring sites in the deep groundwater overexploitation zone, and 241 points in the deep groundwater overexploitation critical zone were selected.

[0067] Table 1 Number of groundwater monitoring stations in deep and shallow groundwater overexploitation areas

[0068]

[0069] 3. Evaluation station network for river and lake water replenishment areas

[0070] According to key water replenishment actions such as ecological water replenishment for river and lake recovery in North China, the full connection of the Beijing-Hangzhou Grand Canal and Zhanghe River, ecological water dispatch of Yongding River, and mother river recovery action, the evaluation station network was selected and determined. For the ecological environment recovery action of rivers and lakes in North China, 608 groundwater monitoring stations were selected within 5 kilometers on both sides of 22 typical rivers and lakes, and 1,067 groundwater monitoring stations were selected within 10 kilometers. For the water replenishment action for the full connection of the Beijing-Hangzhou Grand Canal, 161 shallow and deep groundwater monitoring stations within 0-10 kilometers were selected. For the ecological water dispatch of Yongding River, 83 stations within 10 km around Yongding River in the plain area below Guanting Reservoir (42 stations within 5 km), 27 in Yuquan Mountain and surrounding areas of Yongding River, and 469 groundwater monitoring stations in the plain area of ​​the lower reaches of the North Four Rivers were selected.

[0071] 4. Sea (salt) water intrusion area assessment station network and its application

[0072] (1) Site selection

[0073] The distribution of shallow salty and brackish water in the eastern part of the North China Plain has led to the main exploitation of deep groundwater. The deep groundwater is in a state of overexploitation, and the salt water level has obviously moved down, causing large-scale salt water intrusion into fresh water. The sea (salty) water intrusion area in the Haihe River Basin is distributed in the southern part of Tianjin, the western part of Cangzhou, the southern part of Hengshui, and most of the northern Shandong Plain. There are 314 shallow groundwater monitoring stations distributed in the salt water area.

[0074] Table 2 Distribution of shallow groundwater monitoring stations in saline areas

[0075] province Area (square kilometers) Number of sites Tianjin 1528.38 20 Hebei 6253.56 71 Shandong 30015.31 224

[0076] (2) Analysis and application

[0077] Using the evaluation station network, the year 2018, before the implementation of comprehensive management of groundwater overexploitation and large-scale ecological water replenishment in North China, was used as the base year, and 2023 was used as the current year to analyze the TDS and Cl values ​​of shallow and deep groundwater in key areas. - The concentration distribution range has changed, and a preliminary assessment of the sea (salt) water intrusion situation in the Haihe River Basin has been conducted:

[0078] From the perspective of spatial distribution, the shallow groundwater TDS>2gL and Cl - Salt water bodies with TDS>250mg / L are mainly distributed in the central plain and eastern coastal areas, including Qinhuangdao, Tangshan, Tianlu, Cangzhou, Hengshui, etc. The salinity of shallow groundwater gradually increases from inland to coastal areas. Deep groundwater is mainly freshwater, with TDS>2g / L and Cl - Salt water bodies with a salinity of >250 mg / L are mainly distributed in the southern plains and the eastern coastal areas, including Tianlu, Handan, Langfang, etc. The salinity of deep groundwater is generally high in the southeast and low in the northwest.

[0079] From the evolution law, compared with 2018, the TDS of shallow groundwater in the plain area of ​​the Haihe River Basin will be less than 2g / L and Cl - The area of ​​freshwater areas with concentrations below 250 mg / L is generally increasing, while the area of ​​saltwater areas is decreasing and the degree of salinization is decreasing, showing an overall phenomenon of "saltwater retreating eastward". Compared with 2018, the area of ​​deep groundwater salt and freshwater areas is generally stable from 2021 to 2023.

[0080] 3. Research conclusions and application effects of the present invention:

[0081] (1) For the first time, a unified groundwater station network system was constructed at the basin level in the Haihe River Basin. Based on the classification of aquifer groups in the North China Plain, combined with hydrogeological profiles and drilling data, and making full use of the existing national and provincial groundwater station network distribution and monitoring information, more than 6,700 groundwater monitoring stations in the basin were uniformly stratified and grouped. The monitoring stations in the plain area used the aquifer bottom elevation data to divide the aquifer groups. At the same time, 30 hydrogeological profiles in the plain area were used for verification. The 5,935 groundwater monitoring stations in the plain area were divided into four aquifers, and the 770 monitoring stations in the mountainous area were divided according to pore water, fissure water and karst water, forming a set of stratification results for groundwater monitoring stations in the entire basin.

[0082] (2) A regional station network system was constructed and applied to the dynamic evaluation of groundwater in key areas. Based on the key evaluation areas of different types of basins, the over-exploitation areas, river and lake water replenishment areas, and sea (salty) water intrusion areas were divided according to the evaluation station network determination principle, forming an evaluation station network system for different types of areas. It was applied to the evaluation of water replenishment effects such as ecological water replenishment for river and lake recovery in North China, the full connection of the Beijing-Hangzhou Grand Canal and Zhanghe River, the ecological water dispatch of the Yongding River, and the Mother River Recovery Action, which effectively supported the evaluation of river and lake recovery and groundwater over-exploitation control.

[0083] (3) Based on the work of groundwater station network construction and analysis and evaluation, three technical guidelines applicable to the whole country were formulated, namely, groundwater funnel evaluation, river and lake water replenishment monitoring and evaluation, and groundwater dynamic evaluation. The technical guidelines for groundwater funnel evaluation specifically stipulate the data, evaluation indicators, evaluation methods, classification standards and results of funnel evaluation, and provide technical specifications for the distribution, scale and change of evaluation funnels. The technical guidelines for river and lake water replenishment monitoring and evaluation specifically stipulate the selection and layout of surface water volume, river and lake water surface area, groundwater level, water quality, water body sedimentation, aquatic biological monitoring station network, monitoring items, monitoring frequency, etc., and clarify the main content and technical methods of ecological water replenishment effect evaluation. The technical guidelines for groundwater dynamic evaluation stipulate the determination of evaluation units and station networks, groundwater monitoring data processing, dynamic analysis and evaluation methods of various elements, and analysis and evaluation results. The three technical system standards provide key technical support for groundwater early warning control, over-exploitation management evaluation, etc., and have important promotion and guidance significance.

[0084] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A unified groundwater station network system, characterized in that: It includes unified division of groundwater monitoring stations and construction of regional station network system; The unified division of groundwater monitoring stations is that water conservancy stations, provincial stations and natural resources stations establish a unified evaluation station network system based on the elevation contour lines of the bottom plate of the aquifer group, typical hydrogeological profiles and typical hydrogeological boreholes. The groundwater monitoring points in the region are divided into the corresponding hydrogeological profiles according to the principle of the closest distance; the plain area is divided into a single-layer structure area and a multi-layer structure area. The multi-layer structure area is divided into four aquifer groups from top to bottom. The bottom interface of the first aquifer group is buried at a depth of 10-50m, the bottom interface of the second aquifer group is buried at a depth of 120-210m, the bottom boundary of the third aquifer group is buried at a depth of 250-310m, and the bottom boundary of the fourth aquifer group is to the bottom boundary of the research depth; the water-bearing media in the hilly area are divided into three types, including loose rock porous water aquifer groups in intermountain basins, carbonate rock karst aquifer groups and fracture porous water aquifer groups; The regional station network system is selected by combining points, lines and surfaces within the delineated evaluation unit. If there are multiple aquifer groups in the evaluation unit, the representative stations should be selected in layers, including the over-exploitation area evaluation station network, the river and lake water replenishment area evaluation station network and the sea / saltwater intrusion area evaluation station network, to form a dynamic analysis and evaluation of water level; the over-exploitation area evaluation station network includes shallow over-exploitation area, deep over-exploitation area and funnel area, and the sea / saltwater intrusion area evaluation station network is based on TDS and Cl - The evaluation indicators of sea / saltwater intrusion status are divided into seawater intrusion area and saltwater distribution area.

2. A groundwater unified station network system according to claim 1, characterized in that: Based on the contour maps of the bottom elevations of different aquifer groups within the region, the monitoring layers where the groundwater monitoring stations are located are uniformly divided, and then the typical hydrogeological profiles in the region are used to verify the monitoring layers. In areas where the profiles are sparsely distributed, the hydrogeological boreholes in the region are collected, and the aquifer characteristics of the boreholes are further used to divide the hydrogeological conditions of the groundwater monitoring wells. The groundwater monitoring points in the region are divided into their respective hydrogeological profiles based on the principle of the closest distance.

3. A groundwater unified station network system according to claim 1, characterized in that: When selecting a station network in a groundwater overexploitation area, all monitoring stations within the overexploitation area and near its boundaries should be selected as representative stations based on the actual distribution of the station network.

4. A groundwater unified station network system according to claim 3, characterized in that: When selecting a station network in a groundwater funnel area, the evaluation unit should be determined with the goal of understanding the changes in the elements of the groundwater drawdown funnel. Representative stations should be selected in the center area, transition area, and edge area of ​​the funnel in a cross or cross shape. The production well should be selected as the representative station in the center area of ​​the funnel.

5. A groundwater unified station network system according to claim 4, characterized in that: A station network is selected in the river and lake ecological water replenishment area, and representative stations are selected symmetrically in the four directions of the lake shape. Shallow stations are mainly selected to reflect the changes in shallow groundwater levels, and some deep stations are selected to compare and analyze the hydraulic connection between deep and shallow layers or to indirectly reflect the changes in groundwater extraction.

6. A groundwater unified station network system according to claim 5, characterized in that: When selecting a station network in seawater intrusion areas and salt water distribution areas, representative stations should be selected in coastal plain areas, near inland salt lakes or salt ponds, and in areas where fresh and salt water alternately distribute, along the groundwater flow direction, vertically on the shore, or at the interface between fresh and salt water.

7. A groundwater unified station network system according to claim 6, characterized in that: In areas where intense exploitation of deep groundwater has caused the upper layer of water to move downward, representative stations should be selected in accordance with the principle of selecting as many as possible.

Images