River-side water source recharge capacity evaluation method based on surface water-underground water process coupling simulation

Abstract

The invention discloses a riverside water source recharge capacity evaluation method based on surface water-underground water process coupling simulation, and relates to the technical field of water resource evaluation. The method comprises the following steps: constructing a surface water-underground water coupling model according to basic data of a target riverside water source; the surface water-underground water coupling model comprises a surface water model constructed by an MIKE 11 model and an underground water model constructed by an MIKE SHE model; based on the basic data, a surface water-underground water coupling model and a Pearson correlation analysis method, key driving factors of the underground water level in the target riverside water source are determined, and model simulation working conditions are determined according to the key driving factors; and determining the water resource quantity of water circulation conversion based on the model simulation working condition, and calculating the replenishment contribution degree of each replenishment quantity under different working conditions. The coupling process between the surface water and the underground water can be comprehensively considered, and the accuracy of riverside water source recharge capacity evaluation is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water resource assessment, and in particular to a method for evaluating the recharge capacity of a riverside water source based on surface water-groundwater process coupling simulation. Background Art

[0002] There are often technical limitations and deficiencies in the existing evaluation methods for the recharge capacity of riverside water sources. Most traditional evaluation methods rely on a single hydrological model, such as using only a surface water model or a groundwater model to evaluate the recharge capacity of a water source. However, this method ignores the complex interactions and dynamic balance between surface water and groundwater, resulting in inaccurate and incomplete evaluation results.

[0003] Specifically, there is a close water exchange and material migration process between surface water and groundwater, which has an important impact on the recharge capacity of riverside water sources. For example, the infiltration of surface water, the rise of groundwater, and the lateral flow between the two are all key factors that determine the recharge capacity of water sources. However, the traditional single model cannot effectively simulate these complex coupling processes, thus limiting the accuracy and practicality of the evaluation.

[0004] In addition, existing evaluation methods usually rely on experience and qualitative analysis when determining key driving factors and simulating working conditions, and lack scientific data support and quantitative analysis methods. This makes the evaluation results easily affected by subjective factors, making it difficult to ensure the objectivity and accuracy of the evaluation. Summary of the invention

[0005] The purpose of the present invention is to provide a method for evaluating the recharge capacity of a riverside water source based on surface water-groundwater process coupling simulation, which can comprehensively consider the coupling process between surface water and groundwater and improve the accuracy of the evaluation of the recharge capacity of a riverside water source.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A method for evaluating the recharge capacity of riverside water sources based on coupled simulation of surface water and groundwater processes, including:

[0008] Obtain basic data of target riverside water source areas;

[0009] A surface water-groundwater coupling model is constructed according to the basic data; the surface water-groundwater coupling model includes a surface water model and a groundwater model connected in sequence; the surface water model is constructed based on the MIKE 11 model; the groundwater model is constructed based on the MIKE SHE model;

[0010] Based on the basic data, the surface water-groundwater coupling model and the Pearson correlation analysis method, determine the key driving factors of the groundwater level in the target riverside water source area, and determine the model simulation conditions according to the key driving factors;

[0011] Based on the model simulation working conditions, the amount of water resources converted in the water cycle is determined, and the replenishment contribution of each replenishment amount under different working conditions is calculated.

[0012] Optionally, the construction process of the surface water-groundwater coupling model includes: coupling the surface water model and the groundwater model in time with a monthly step, and realizing the coupling of the two by using the dynamic water level in the middle of the Yellow River section simulated by the MIKE 11 model as the northern boundary input of the groundwater model.

[0013] Optionally, the MIKE 11 model is used to simulate any surface river flow, water level and sediment transport process; the MIKE SHE model is used to simulate topography, overland flow, land use, precipitation, evapotranspiration, unsaturated and saturated groundwater flow, and the interactions between various types.

[0014] Optionally, the MIKE 11 model is based on solving the Saint-Venant equations and consists of momentum and energy equations, specifically:

[0015]

[0016] Where Q is the flow rate, m is 3 / s; q is the single-width inflow, m 3 / s; A is the water flow area, m 2 ; h is the water level, m; R is the hydraulic radius, m; C is the Xie Cai coefficient; α is the momentum correction coefficient; g is the gravitational acceleration.

[0017] Optionally, the construction process of the MIKE 11 model includes:

[0018] The river network file, section file, boundary file and parameter file are input into the simulation file for coordination and integration, the simulation time step is set, the simulation status is run and checked, a complete overall file is formed, and a constructed one-dimensional hydrodynamic model is obtained; the boundary file includes a time series file.

[0019] Optionally, the river network file includes a mileage coordinate table of water sources, which is used to define the flow direction of the river; the section file includes the geometric dimensions of the section; the boundary file also includes external boundary conditions and internal boundary conditions; the parameter file includes the river leakage coefficient and Manning coefficient.

[0020] Optionally, both the external boundary conditions and the internal boundary conditions include boundaries and corresponding condition values; wherein the external boundary includes the starting point, end point and endpoint of the river channel and the end point of the sewer outlet; the internal boundary includes precipitation inflow, factory drainage and water intake of the water plant; the condition value adopts any one of a constant value, time-varying data and periodic data.

[0021] Optionally, the key driving factors are Huayuankou flow, water level and groundwater extraction and groundwater level of the southern surrounding aquifer.

[0022] Optionally, the calculation formula for the replenishment contribution is:

[0023] G=B / Z×100%

[0024] In the formula, G is the contribution of the water source, %; B is the recharge of various items, including vertical recharge of groundwater from precipitation and evaporation, boundary inflow recharge and lateral seepage recharge from the Yellow River; Z is the total recharge of the water source.

[0025] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0026] The present invention discloses a method for evaluating the recharge capacity of a riverside water source based on surface water-groundwater process coupling simulation, the method comprising obtaining basic data of a target riverside water source; constructing a surface water-groundwater coupling model according to the basic data; the surface water-groundwater coupling model comprising a surface water model constructed by a MIKE 11 model and a groundwater model constructed by a MIKESHE model; based on the basic data, the surface water-groundwater coupling model and the Pearson correlation analysis method, determining the key driving factors of the groundwater level in the target riverside water source, and determining the model simulation conditions according to the key driving factors; determining the amount of water resources converted by water cycle based on the model simulation conditions, and calculating the recharge contribution of each recharge amount under different conditions. The present invention can comprehensively consider the coupling process between surface water and groundwater, simulate the amount of water resources converted by water cycle by constructing a surface water-groundwater coupling model, and determine the key driving factors and simulation conditions based on a scientific analysis method, thereby accurately evaluating the recharge capacity of the riverside water source. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1It is a schematic flow chart of the method for evaluating the replenishment capacity of a riverside water source area of ​​the present invention;

[0029] Figure 2 A logical schematic diagram for the overall construction of contribution evaluation in this embodiment;

[0030] Figure 3 Schematic diagram of ground elevation in this embodiment;

[0031] Figure 4 Schematic diagram of the bottom plate elevation of the aquifer in this embodiment;

[0032] Figure 5 This is the initial groundwater level map of the model in this embodiment. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The purpose of the present invention is to provide a method for evaluating the recharge capacity of a riverside water source based on surface water-groundwater process coupling simulation, which can comprehensively consider the coupling process between surface water and groundwater and improve the accuracy of the evaluation of the recharge capacity of a riverside water source.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1-Figure 2 As shown, the present invention provides a method for evaluating the recharge capacity of a riverside water source based on coupled simulation of surface water and groundwater processes, comprising:

[0037] Step 100: Obtain basic data of the target riverside water source.

[0038] Step 200: construct a surface water-groundwater coupling model based on the basic data; the surface water-groundwater coupling model includes a surface water model and a groundwater model connected in sequence; the surface water model is constructed based on the MIKE 11 model; the groundwater model is constructed based on the MIKE SHE model.

[0039] Step 300: Based on the basic data, the surface water-groundwater coupling model and the Pearson correlation analysis method, determine the key driving factors of the groundwater level in the target riverside water source, and determine the model simulation conditions according to the key driving factors.

[0040] Step 400: Determine the amount of water resources converted by water circulation based on the model simulation working conditions, and calculate the replenishment contribution of each replenishment amount under different working conditions.

[0041] Based on the above technical solution, a detailed processing process of each step is provided.

[0042] As a specific implementation, step 200 is described in detail.

[0043] The basic models MIKE 11 and MIKE SHE are used in constructing the surface water-groundwater coupling model. For the basic model MIKE 11, MIKE 11 includes one-dimensional, two-dimensional and three-dimensional models according to the characteristics of the river channel morphology. The Yellow River channel in the northern part of the study area belongs to the lower reaches of the Yellow River. The river channel is relatively wide. In theory, a two-dimensional hydrodynamic model should be established. However, in this study, only the surface water model is used to calculate the dynamic water level in the middle section of the Yellow River and input it into the groundwater model to complete the coupling. The focus is on the water recharge interaction between the Yellow River and groundwater, so the one-dimensional MIKE 11 model is simplified. The MIKE 11 model is based on the solution of the Saint-Venant equations and consists of momentum and energy equations. The specific formula is as follows:

[0044]

[0045] Where Q is the flow rate, m is 3 / s; q is the single-width inflow, m 3 / s; A is the water flow area, m 2 ; h is the water level, m; R is the hydraulic radius, m; C is the Xie Cai coefficient; α is the momentum correction coefficient; g is the gravitational acceleration.

[0046] For the basic model MIKE SHE, it has a complete set of pre-processing and post-processing tools, mainly including process models of evapotranspiration, surface flow, unsaturated flow, groundwater flow and channel flow and their interactions. The MIKE series of models include many categories such as MIKE 11, MIKE 21, MIKE 31 and MIKE SHE, and users can flexibly combine them according to their needs. Among them, MIKE SHE is a unique software package for simulating all major processes in the land stage of the hydrological cycle. It is a dynamic, user-friendly modeling tool that can be applied to diversified scales from local infiltration studies to regional watershed studies.

[0047] Therefore, based on the basic principles of the above model, the MIKE 11 model is first constructed:

[0048] The MKE11 model is a software system used to simulate the flow, water level, and sediment transport of any surface river. Specifically, it can simulate the one-dimensional river network flow dynamics, floods, water quality, sediment transport, dam breaches, etc. This study requires the establishment of a one-dimensional Yellow River hydrodynamic model, so only the one-dimensional river network hydrodynamic module is used. A complete one-dimensional Yellow River hydrodynamic model is constructed by inputting the river network, section, boundary (including time series file) and parameter file into the simulation file.

[0049] River network file: The river network file (nwk11) needs to define the flow direction of the river. This study imported the existing river file (shape) from ArcGIS and manually modified the starting point of the river mileage according to the actual situation. The final Yellow River mileage coordinates are shown in Table 1.

[0050] Table 1 Yellow River Mileage Coordinates

[0051]

[0052]

[0053] Section file: The geometric dimensions of the section have a key impact on the water flow, flow rate and flow velocity of the river. According to the existing data files, the data of 10 sections from Taohuayu to Huayuankou are selected and imported to form a complete section file (xns11).

[0054] Boundary file: MIKE 11 contains two types of boundaries, namely external boundary conditions (Open boundary) and internal boundary conditions (Additional boundary). External boundaries are endpoints such as the start and end points of rivers and sewer outlets. The inflow and outflow of water flow mean the increase and decrease of regional water volume respectively. Internal boundaries are places such as precipitation inflow, factory drainage and water plant water intake that flow into or out of the model. External boundaries must be set, while internal boundaries are not required.

[0055] The value of the boundary condition can be a constant value, time-varying data (dfs0 file) or periodic data. This study uses time-varying data (dfs0 file). The river channel in the northern part of the study area is the Yellow River section from Taohuayu section to Huayuankou section. The daily water level of Huayuankou from 2016 to 2018 downloaded from the "Official Website of the Yellow River Conservancy Commission" is used as the lower boundary condition, and the upstream flow boundary is the daily flow data of Taohuayu upstream from 2016 to 2018 downloaded from the "Official Website of the Yellow River Conservancy Commission".

[0056] Parameter file: The parameter file (HD 11) mainly defines basic hydraulic variables and parameters. The parameter file of this study mainly sets parameters such as river leakage coefficient and Manning coefficient. The initial value range of river permeability coefficient is generally 1×10-5~1×10-6, and the initial value range of Manning coefficient is generally 10~50. The initial values ​​of this study are 1*10-5 and 30, and they will be calibrated later.

[0057] Simulation file: The simulation file coordinates and integrates the constructed river network file, section file, boundary file and parameter file to form a complete overall file. In the simulation file, set the simulation time step, run and view the simulation status.

[0058] Then, the MIKE SHE model is constructed:

[0059] The main processes simulated by MIKE SHE include topography, land use, precipitation, evapotranspiration, snowmelt, irrigation, surface runoff, unsaturated flow and saturated zone groundwater flow and their interactions. Modelers can flexibly combine various modules according to actual research needs. This study mainly covers modules such as topography, overland flow, land use, precipitation, evapotranspiration, unsaturated zone and saturated zone. Due to the rapid urbanization of Jiuwutan Water Source in recent years, the area of ​​impervious ground has increased significantly, and the irrigation infiltration recharge of groundwater is negligible relative to precipitation and the recharge flow of surrounding aquifers, so the irrigation module is no longer considered.

[0060] Grid division: Import the remote sensing map of the study area into ArcGIS software, and draw the corresponding study boundary based on the land use and other conditions of the study area. Finally, export the vector format file (shape) containing the boundary information and input it into the corresponding model range and boundary module of MIKESHE. The model origin coordinates X0 = 3864169, Y0 = 452881. Divide the study area into 3520 grids, with N horizontal directions. x =88, vertical direction N y =40, and the grid size is set to 119m×119m.

[0061] Topography: Jiuwutan water source is a floodplain landform in the Huangqin (Yellow River, Qin River) alluvial plain. The terrain in this area is flat, with a ground elevation of 92 to 95 meters, and it is generally slightly inclined to the southeast. The surface elevation diagram is shown in Figure 3 The southern part of this area is adjacent to the Huanghuai alluvial plain. Based on the existing elevation points in Huiji District, ArcGIS was used to cut out the elevation points within the Jiuwutan water source area, and the elevation data was input into the terrain module in MIKE SHE. The bilinear interpolation method was used, and the search radius was set to 1km to automatically generate a terrain interpolation map.

[0062] Slope flow: Slope flow simulates the flow of surface water along with terrain and other factors. It can be used to calculate the flow in floodplains or the flow of runoff to streams. The finite difference method uses the diffusion wave approximation. When calculating local surface flow and runoff, it should be used to simulate the slope flow calculation. The basic parameters required for its calculation are the Manning coefficient, the detention depth and the initial water depth. The Manning coefficient is the reciprocal of the roughness n, and generally takes a value of 10 to 100. The detention depth refers to the maximum depth of water flowing over the ground. The initial water depth of the model is usually set to 0m, otherwise as long as the internal water level is lower than the non-zero initial water depth value, water will flow into the boundary, and the boundary will be regarded as a water source. This study takes the initial values ​​of the three as 2m respectively. 1 / 3 / s, 2mm and 0m.

[0063] Land use: In 2016, the land use types in the study area were mainly divided into five categories: fields, forests, grasslands, water bodies and impervious surfaces. Among them, fields accounted for the largest proportion of 59.20%, followed by impervious surfaces accounting for 33.83%, and the remaining water bodies, forests and grasslands accounted for 3.88%, 3.07% and 0.03% respectively. Due to the rapid development of the region in the past decade, a large amount of land has been expropriated, and the irrigation volume of the remaining land has gradually decreased. In this example, the irrigation recharge infiltration volume is no longer considered.

[0064] The leaf area index and root depth values ​​for different land use types are shown in Table 2.

[0065] Table 2 Leaf area index and root depth values

[0066]

[0067]

[0068] Meteorological data: Jiuwutan water source is located in the northern part of Zhengzhou City. It has a warm temperate semi-humid climate with distinct four seasons. Precipitation is mainly concentrated in July to September, and the temperature difference between day and night is large. The model selects the precipitation and evaporation data of Zhengzhou Hydrological Station from 2016 to 2018. The average annual precipitation in the region is 680.2mm, the maximum monthly precipitation is 243.7mm in July 2016, and there is no precipitation in October 2018. It can be seen that the precipitation distribution is uneven during the year, with precipitation concentrated in July to September, accounting for about 53% of the annual precipitation. The average annual evaporation in the region is 1193.4mm, the maximum monthly evaporation is 148.9mm in June 2016, and the minimum monthly evaporation is 36.3mm in January 2016. It can be seen that the evaporation is unevenly distributed during the year, with evaporation mostly concentrated in June to September, accounting for about 53% of the annual evaporation.

[0069] Unsaturated zone: The water flow in the unsaturated zone is mainly affected by gravity, so it is set as one-dimensional vertical flow. The soil in the unsaturated zone of the study area is mainly Holocene alluvial powder and fine sand layer, which is relatively loose. According to its hydrogeological conditions, the top plate of the aquifer section above the groundwater is buried at a depth of 2 to 4 meters, and the thickness of the soil layer is taken as 3 meters. The specific division is shown in Table 3.

[0070] Table 3 Vertical division of unsaturated zone

[0071]

[0072] Saturated zone: The saturated zone module needs to define mainly geological layers, numerical layers and production well information.

[0073] (1) Geological layer: The regional soil is mainly Holocene and Upper Pleistocene alluvial-lacustrine silt, fine sand and medium-coarse sand, without a continuous and stable aquiclude. Therefore, the model is generalized into a single-layer, isotropic, non-steady flow three-dimensional model. According to the "Ninth Five-Year Plan Beach Water Supply Hydrogeological Survey Report for the Northern Suburbs of Zhengzhou City, Henan Province", the thickness of the aquifer at the relevant points was queried, and the bottom elevation of the aquifer was obtained by kriging interpolation using ArcGIS. Figure 4 The main parameters are: the elevation of the aquifer bottom plate, the vertical and horizontal permeability coefficients of the aquifer, the water supply degree and the water storage coefficient.

[0074] (2) Numerical layer: As an independent layer, the numerical layer needs to define the initial water depth and external boundary. Since the study area is small, the initial water depth is set based on the buried depth points near and within the study area. Figure 5 The northern edge of the Yellow River receives recharge from the Yellow River and takes the variable head boundary. The western mountainous area receives lateral seepage recharge and takes the fixed head boundary. The southern part is the discharge boundary and takes the fixed head boundary. The upper part is the precipitation infiltration and evaporation boundary. The groundwater mainly considers shallow water, and the junction of shallow and deep groundwater is generalized as a water-proof bottom plate.

[0075] (3) Production wells: The annual production of water wells in the study area during the simulation period was 17.947 million m 3 , 17.41 million m 3 and 17.2 million m 3 According to calculations, the daily production of each well is basically 1300m 3 about.

[0076] Finally, a surface water-groundwater coupling model was constructed and the model was calibrated and verified.

[0077] As a specific implementation, step 300 and step 400 are described in detail.

[0078] Based on the above-mentioned model, the Pearson correlation analysis method is first used to obtain the key driving factors of the groundwater level in the study area, and the source of the contribution and the calculation principle in this study are introduced. Then, the simulation conditions of the model are reasonably determined according to the key factors obtained. Finally, the amount of water resources transformed by the water cycle of the Jiuwutan water source is obtained, the recharge contribution of each recharge amount under different conditions is calculated, and the distribution characteristics of regional groundwater are discussed and analyzed.

[0079] The sources and calculations of contribution specifically include:

[0080] Contribution is an indicator for exploring economic benefits. It refers to the ratio of the number of effective results to the amount of resource consumption and occupation, that is, the ratio of output to input, or the ratio of income to expenditure. Calculation formula:

[0081] Contribution (%) = contribution (output, income) / input (consumption, occupation) × 100%

[0082] This study is to quantitatively study the proportion of various recharges in the water source to the total recharge of the water source, borrowing the term contribution in economics. The contribution is set as the proportion of various recharges in the water source to the sum of the recharges of the water source, and the calculation formula is:

[0083] G=B / Z×100%

[0084] Where G is the contribution of the water source, %; B is the recharge of each item. This study mainly calculates the vertical recharge of groundwater including precipitation and evaporation, boundary inflow recharge and lateral seepage recharge of the Yellow River; Z is the total recharge of the water source, which is obtained through the groundwater balance item of the WaterBalance model. The specific contribution can reflect the recharge contribution of each recharge source.

[0085] The groundwater balance term of the WaterBalance model mainly includes the following five parts:

[0086] ① Vertical groundwater recharge (discharge) refers to the difference between precipitation infiltration and groundwater evaporation. A negative value (-) indicates groundwater discharge, that is, precipitation infiltration is less than groundwater evaporation; a positive value (+) indicates groundwater recharge, that is, precipitation infiltration is greater than groundwater evaporation.

[0087] ② Boundary inflow (outflow) refers to the amount of water flowing out or in through the lateral boundary of the model. Among them, negative values ​​(-) represent groundwater discharge, that is, groundwater flows from the study area to the outside of the boundary, and positive values ​​(+) represent groundwater recharge, that is, groundwater flows from the outside of the boundary into the study area.

[0088] ③ Groundwater storage variable refers to the groundwater storage variable caused by groundwater level changes, where a negative value (-) is the change in aquifer storage caused by rising groundwater levels; a positive value (+) is the change in aquifer storage caused by lowering groundwater levels.

[0089] ④ Water source extraction volume, that is, the extraction volume of water source extraction wells from the water source. A negative value (-) indicates the extraction volume of water source extraction wells from the water source.

[0090] ⑤Yellow River recharge refers to the recharge of the Yellow River to groundwater, where a positive value (+) indicates that the river water recharges groundwater.

[0091] Analysis on water source conversion process and contribution under the condition of Yellow River water level change

[0092] Analysis of different recharge conditions of the Yellow River: According to the "Nine-Five" Beach Water Supply Hydrogeological Survey Report in the Northern Suburbs of Zhengzhou City, Henan Province, the average water level of the Yellow River for many years is 91.70m, the highest water level is 94.08m, and the lowest water level is not less than 90m. Therefore, although the riverbed of the Yellow River in this section is still lower than the surface of both banks, it does not present a typical "hanging river on the ground". According to the water level and flow data collected from the Huayuankou Hydrological Station of the Yellow River from 2016 to 2018, the water level of the Yellow River during this period was 90.88m at the highest level, not less than 87.07m at the lowest level, 4470m3 / s at the maximum flow, and 168m3 / s at the minimum flow. By comparing the water level data before the construction of the Jiuwutan Water Source (1989) and the water level data of the Huayuankou Hydrological Station of the Yellow River after the construction, it can be seen that the riverbed of the Yellow River at the Huayuankou Hydrological Station is severely cut, and the highest water level has dropped by about 3m. Before water and sediment regulation, the riverbed of the Yellow River rose by about 0.05 to 0.1 m per year, and the riverbed was usually 4 to 6 m higher than the back river ground. After the water and sediment regulation of Xiaolangdi and other reservoirs in 2003, the riverbed of the lower reaches of the Yellow River dropped by 1 to 2 m. After the water and sediment regulation of the Yellow River, the riverbed elevation and corresponding water level changed, and the lateral recharge capacity of the Yellow River changed accordingly. Therefore, the following three working conditions are set.

[0093] (1) Yellow River high water level condition (H1 before water and sediment diversion): This condition is before the Yellow River is diverted and silted, when the riverbed and water level of the Yellow River are relatively high. By setting this condition, the replenishment and drainage conditions of the Yellow River before water and sediment diversion can be simulated;

[0094] (2) Yellow River low water level condition (after water and sediment diversion, i.e., current condition H2): This condition is after the Yellow River has been diverted and silted. Under current conditions, the Yellow River bed has been cut more severely than before the diversion and silt diversion, and the Yellow River water level has also dropped significantly compared to before the diversion and silt diversion. By setting this condition, the replenishment and drainage conditions of the Yellow River under the current conditions can be simulated;

[0095] (3) Future conditions of the Yellow River (further water and sediment regulation of the Yellow River H3): This condition is that as the water and sediment regulation of the Yellow River continues, the water level of the Yellow River bed will further drop. Through the setting of this condition, the drainage conditions of the Yellow River under the condition of further cutting of the Yellow River bed in the future can be simulated.

[0096] Analysis of the water source conversion process and contribution evaluation before the Yellow River water and sediment diversion: Under this condition, it is assumed that the Yellow River water and sediment diversion has not been carried out and the water level of the Yellow River is relatively high. The water balance calculation results of the groundwater in the study area based on the model WaterBalance module show that the underground vertical recharge is 886,400 m 3 , the lateral recharge of the aquifer is 1.8743 million m 3 , the Yellow River recharge is 33.0438 million m3, and the boundary outflow is -5.6387 million m 3 , groundwater storage volume -12.7561 million m 3 , water source extraction volume - 17.4105 million m 3 The balance error is -0.08 million m 3 .

[0097] It can be seen that under this condition, due to the high water level of the Yellow River, which is higher than the ground elevation on both sides of the Yellow River, the groundwater level is shallow and the evaporation is large, but the groundwater is very susceptible to precipitation recharge. The groundwater level of the No. 310 groundwater observation well increased by 0.24m during the simulation period, and the groundwater flow rate in the north was significantly greater than that in the south. According to calculations, the contribution of vertical groundwater recharge is 2.48%, the contribution of lateral aquifer recharge is 5.23%, and the contribution of Yellow River recharge is 92.29%.

[0098] Analysis of water source conversion process and contribution evaluation after the Yellow River water and sediment diversion: After the Yellow River water and sediment diversion, the riverbed of the Yellow River in the region was severely cut. According to the water balance calculation results of the model WaterBalance module for the groundwater in the study area, the vertical recharge of groundwater is 871,200 m 3 , the lateral recharge of the aquifer is 1.8653 million m 3 The Yellow River recharge is 27.886 million m 3 , Boundary outflow - 4.2899 million m 3 , groundwater storage volume -8.9232 million m 3 , water source extraction volume - 17.4105 million m 3 , balance error -1200m 3 .

[0099] Under this condition, since the Yellow River bed is cut down by 1-2m compared with the Yellow River before water and sediment regulation, the water level of the Yellow River has also dropped to a certain extent. The groundwater level on both sides of the Yellow River is relatively deep compared with the Yellow River before water and sediment regulation, and the evaporation is correspondingly reduced compared with the Yellow River before water and sediment regulation. The groundwater level of the No. 310 groundwater observation well decreased by 0.08m during the simulation period, and the groundwater flow velocity in the north was significantly greater than that in the south. According to calculations, the contribution of groundwater vertical recharge is 2.84%, the contribution of aquifer lateral recharge is 6.09%, and the contribution of Yellow River recharge is 91.07%.

[0100] Analysis of the water source conversion process and contribution evaluation after the Yellow River further diverts water and sediment: This condition is based on the current riverbed of the Yellow River. As the Yellow River further diverts water and sediment, the riverbed of the Yellow River continues to cut down on the existing basis. Under this condition, the water balance calculation results of the groundwater in the study area based on the model WaterBalance module show that the underground vertical recharge is 820,200 m 3 , the lateral recharge of the aquifer is 1.8195 million m 3 The Yellow River recharge is 24.1087 million m 3 , Boundary outflow - 3.0221 million m 3 , groundwater storage volume -6.3171 million m 3 , water source extraction volume - 17.4105 million m 3 The balance error is -1300m 3 .

[0101] Through the above equilibrium analysis, under this condition, as the Yellow River bed continues to cut down 1-2m compared with the current situation, the Yellow River water level further drops, the groundwater level on both sides of the Yellow River is further increased, and the evaporation is reduced compared with the current situation. The groundwater level of the No. 310 groundwater observation well decreased by 0.36m during the simulation period, and the groundwater flow rate in the north is significantly greater than that in the south. According to calculations, the contribution of vertical groundwater recharge is 3.07%, the contribution of lateral aquifer recharge is 6.80%, and the contribution of Yellow River recharge is 90.13%.

[0102] Analysis of water source conversion process and contribution under different exploitation conditions in water source areas

[0103] Analysis of different exploitation conditions in water sources: After the water supply of the middle line project, various groundwater pressure extraction measures have been continuously implemented. Although the Jiuwutan water source is still in operation, the extraction volume has been decreasing in recent years. With the continuous increase in water supply, the extraction volume of the Jiuwutan water source has been decreasing. Under the current conditions, the annual extraction volume is about 10 million m 3 Therefore, three working conditions are set:

[0104] (1) Increased mining conditions: This condition is before water is delivered. Jiuwutan Water Source is one of the main water sources for Zhengzhou City. According to the historical mining data of the water source, the maximum annual mining volume of Jiuwutan Water Source is about 20 million m3. 3 Therefore, the annual water extraction volume under this working condition is 20 million m 3 .

[0105] (2) Current mining conditions: This condition mainly considers that after the water is released, although the Jiuwutan water source is still in operation, the mining volume has been decreasing in recent years, from 22.1249 million m in 2009 to 22.1249 million m in 2010. 3 Reduced to 16.0934 million m in 2019 3As the water supply continues to increase, the amount of water extracted from the Jiuwutan water source has been decreasing. Under the current conditions, the annual extraction volume is 10 million m 3 Therefore, the annual water extraction volume under this working condition is 10 million m 3 .

[0106] (3) Future mining conditions: This condition takes into account that as the water supply continues to increase, the Jiuwutan water source will be shut down as a regular water supply source and converted to emergency backup mining. Under this condition, the annual mining volume of the emergency backup water source is about 1 million m 3 Therefore, the annual water extraction volume under this working condition is 1 million m 3 .

[0107] Analysis of water source conversion process and contribution evaluation under the condition of increasing annual extraction volume: Under this condition, the groundwater extraction volume is 20 million m 3 According to the calculation results of the groundwater balance of the study area by the WaterBalance module of the model, the vertical recharge of underground water is 924,200 m 3 , the lateral recharge of the aquifer is 1.8827 million m 3 , the Yellow River recharge is 29.2625 million m 3 , Boundary outflow - 4.2905 million m 3 , groundwater storage volume -7.7784 million m 3 , water source extraction volume - 20 million m 3 , the equilibrium error is 0.05 thousand m3. The groundwater level of the 310 groundwater observation well decreased by 0.43 m during the simulation period, and the groundwater flow velocity in the north was significantly greater than that in the south. According to calculations, the contribution of groundwater vertical recharge is 2.88%, the contribution of aquifer lateral recharge is 5.87%, and the contribution of Yellow River recharge is 91.25%.

[0108] Analysis of water source conversion process and contribution evaluation under the current annual extraction volume: Under this condition, the groundwater extraction volume is 10 million m 3 According to the calculation results of the groundwater balance of the study area by the WaterBalance module of the model, the vertical recharge of underground water is 762,100 m 3 , the lateral recharge of the aquifer is 1.8472 million m 3 The Yellow River recharge is 24.5571 million m 3 , Boundary outflow - 4.4177 million m 3 , groundwater storage volume -12.7478 million m 3 , water source extraction volume - 10 million m 3 The balance error is 0.08 million m 3The groundwater level of the No. 310 groundwater observation well increased by 0.90 m during the simulation period, and the groundwater flow velocity in the north was significantly greater than that in the south. It was calculated that the contribution of vertical groundwater recharge was 2.81%, the contribution of lateral aquifer recharge was 6.80%, and the contribution of Yellow River recharge was 90.39%.

[0109] Analysis of water source conversion process and contribution evaluation under the future annual extraction condition: Under this condition, the groundwater extraction volume is 1 million m 3 The Jiuwutan water source was converted into an emergency backup water source. The water balance calculation results of the groundwater in the study area based on the WaterBalance module of the model showed that the underground vertical recharge volume was 673,200 m 3 , the lateral recharge of the aquifer is 1.8496 million m 3 , the Yellow River recharge is 21.1326 million m 3 , border outflow - 5.0184 million m 3 , groundwater storage volume -17.6359 million m 3 , water source extraction volume - 1 million m 3 The balance error is 1100m 3 The groundwater level of groundwater observation well No. 310 increased by 2.09m during the simulation period, and the groundwater flow velocity in the north was significantly greater than that in the south. It was calculated that the contribution of vertical groundwater recharge was 2.85%, the contribution of lateral aquifer recharge was 7.82%, and the contribution of Yellow River recharge was 89.34%.

[0110] Analysis on water source conversion process and contribution of different groundwater levels in the southern peripheral aquifer

[0111] Analysis of different groundwater level conditions in the southern surrounding aquifer: After the operation of the middle line project, the groundwater level continued to rise, and the groundwater level near the Jiuwutan water source rose by 0-1m, which had a profound impact on the recharge and discharge of the regional groundwater aquifer. Therefore, three different water level conditions were set for the southern fixed head boundary, as shown in Table 4.

[0112] (1) Condition of continued drainage of the southern aquifer (D1): Mainly before water is delivered, groundwater is the main water source of Zhengzhou City, and the groundwater extraction volume is large. Therefore, under this condition, the groundwater level of the aquifer in the southern part of the Jiuwutan water source in Zhengzhou City is relatively low.

[0113] (2) Moderate recovery condition of the southern aquifer (D2): After the water was put into operation, the groundwater extraction was greatly reduced, and the groundwater level of the aquifer in the southern part of the Jiuwu Beach Water Source in Zhengzhou City was restored.

[0114] (3) Increased recovery condition of the southern aquifer (D3): mainly due to the fact that with the water supply, the groundwater extraction volume is further reduced compared with the current situation, and the groundwater level of the aquifer in the southern part of the Jiuwu Beach Water Source in Zhengzhou City is further restored compared with the current situation.

[0115] Table 4 Different working conditions settings

[0116]

[0117] Analysis of water source conversion process and contribution evaluation under the condition of water level decline in the southern surrounding aquifer: This condition refers to the situation before water is delivered. Groundwater is the main water source of Zhengzhou City, and the groundwater extraction volume is large. The southern boundary of the Jiuwutan water source is far from the Yellow River, and the groundwater level is small. Under this condition, the water balance calculation results of the groundwater in the study area based on the model WaterBalance module show that the underground vertical recharge is 928,900 m 3 , the lateral recharge of the aquifer is 2.0306 million m 3 The Yellow River recharge is 26.8983 million m 3 , Boundary outflow - 4.8576 million m 3 , groundwater storage volume -7.5908 million m 3 , water source extraction volume - 17.4105 million m 3 The balance error is -1100m 3 Under this condition, the groundwater level in the No. 310 groundwater observation well decreased by 0.23m during the simulation period, and the groundwater flow rate in the north was significantly greater than that in the south. It was calculated that the contribution of vertical groundwater recharge was 3.11%, the contribution of lateral aquifer recharge was 6.80%, and the contribution of Yellow River recharge was 90.09%.

[0118] Analysis of water source conversion process and contribution evaluation under the condition of unchanged water level in the southern surrounding aquifer: This condition means that after the water is turned on, the groundwater extraction volume is greatly reduced, the groundwater level in Zhengzhou has recovered, and the groundwater level at the southern boundary of the Jiuwutan water source has increased compared with before the water was turned on. Under this condition, the water balance calculation results of the groundwater in the study area based on the model WaterBalance module show that the underground vertical recharge volume is 846,800 m 3 , the lateral recharge of the aquifer is 3.8054 million m 3 The Yellow River recharge is 26.69 million m 3 , Boundary outflow - 3.6638 million m 3 , groundwater storage volume -10.2688 million m 3 , water source extraction volume - 17.4105 million m 3 , the balance error is 0.1 million m 3 .

[0119] Under this condition, the groundwater level of groundwater observation well No. 310 increased by 0.07m during the simulation period, and the groundwater flow velocity in the north was significantly greater than that in the south. It was calculated that the contribution of vertical groundwater recharge was 2.70%, the contribution of lateral aquifer recharge was 12.14%, and the contribution of Yellow River recharge was 85.16%.

[0120] Analysis of water source conversion process and contribution evaluation under the condition of increased water level in the southern surrounding aquifer: In this condition, as the water is released, groundwater extraction is further reduced compared to the current situation, the groundwater level in Zhengzhou City is further restored compared to the current situation, and the groundwater level at the southern boundary of the Jiuwutan water source is further increased compared to the current situation.

[0121] Under this condition, the water balance calculation results of the groundwater in the study area based on the model WaterBalance module show that the underground vertical recharge is 823,500 m 3 , the lateral recharge of the aquifer is 5.6084 million m 3 The Yellow River recharge is 26.9407 million m 3 , Boundary outflow - 2.934 million m 3 , groundwater storage volume -13.0287 million m 3 , water source extraction volume - 17.4105 million m 3 The balance error is 0.08 million m 3 The groundwater level of groundwater observation well No. 310 increased by 0.38m during the simulation period, and the groundwater flow velocity in the north was significantly greater than that in the south. It was calculated that the contribution of vertical groundwater recharge was 2.47%, the contribution of lateral aquifer recharge was 16.81%, and the contribution of Yellow River recharge was 80.73%.

[0122] This example explains the relationship between groundwater level replenishment and drainage and the contribution principle in the study area, and uses the Pearson correlation analysis method to find that the key driving factors of groundwater level changes are Huayuankou flow, water level, groundwater extraction, and groundwater level in the southern surrounding aquifer. The Yellow River flow and water level are closely related, so the water level changes caused by the Yellow River water and sediment diversion, the changes in groundwater extraction, and the water level changes in the southern surrounding aquifer caused by the project are introduced into the model.

[0123] According to the key factors affecting the groundwater level, three working conditions were proposed under different recharge conditions of the Yellow River, different exploitation conditions of the water source, and different groundwater levels of the southern surrounding aquifers. The water source transformation process under different recharge and discharge conditions of the Jiuwutan water source was analyzed for 9 different types of working conditions. The simulation results show that under different recharge conditions of the Yellow River, as the water and sediment regulation of the Yellow River proceeds, the Yellow River bed continues to cut down, the water level of the Yellow River drops, and the recharge of the Yellow River water to groundwater also shows a downward trend. The water level of the plains on both sides of the Yellow River increases, and the contribution of the Yellow River recharge water resources to the groundwater in the water source also decreases from 92.29% to 90.13%. Under different exploitation conditions of the Jiuwutan water source, as the exploitation of the Jiuwutan water source continues to decrease, the recharge of the Yellow River to the water source continues to decrease, and the contribution of the Yellow River recharge water resources to the groundwater in the water source also continues to decrease, from 91.25% to 89.34%. Under different water level conditions of the surrounding aquifers in the south, as the surrounding aquifers continue to recover,

[0124] The Yellow River's recharge volume has been declining, and the contribution of the Yellow River's recharge water resources to the groundwater in the water source area has also been gradually declining, from 90.09% to 80.73%.

[0125] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0126] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for evaluating the recharge capacity of riverside water sources based on coupled simulation of surface water and groundwater processes, characterized in that: include: Obtain basic data of target riverside water source areas; A surface water-groundwater coupling model is constructed according to the basic data; the surface water-groundwater coupling model includes a surface water model and a groundwater model connected in sequence; the surface water model is constructed based on the MIKE 11 model; the groundwater model is constructed based on the MIKE SHE model; Based on the basic data, the surface water-groundwater coupling model and the Pearson correlation analysis method, determine the key driving factors of the groundwater level in the target riverside water source area, and determine the model simulation conditions according to the key driving factors; Based on the model simulation working conditions, the amount of water resources converted in the water cycle is determined, and the replenishment contribution of each replenishment amount under different working conditions is calculated.

2. The method for evaluating the recharge capacity of riverside water sources based on coupled simulation of surface water and groundwater processes according to claim 1 is characterized in that: The construction process of the surface water-groundwater coupling model includes: coupling the surface water model and the groundwater model in time with a monthly step, and realizing the coupling of the two by using the dynamic water level in the middle of the Yellow River section simulated by the MIKE 11 model as the northern boundary input of the groundwater model.

3. The method for evaluating the recharge capacity of riverside water sources based on surface water-groundwater process coupling simulation according to claim 1 is characterized in that: The MIKE 11 model is used to simulate any surface river flow, water level and sediment transport process; the MIKE SHE model is used to simulate topography, overland flow, land use, precipitation, evapotranspiration, unsaturated and saturated groundwater flow, and the interactions between various types.

4. The method for evaluating the recharge capacity of riverside water sources based on surface water-groundwater process coupling simulation according to claim 1 is characterized in that: The MIKE 11 model is based on solving the Saint-Venant equations and consists of momentum and energy equations, specifically: Where Q is the flow rate, m is 3 / s; q is the single-width inflow, m 3 / s; A is the water flow area, m 2 ; h is the water level, m; R is the hydraulic radius, m; C is the Xie Cai coefficient; α is the momentum correction coefficient; g is the gravitational acceleration.

5. The method for evaluating the recharge capacity of riverside water sources based on surface water-groundwater process coupling simulation according to claim 1 is characterized in that: The construction process of the MIKE 11 model includes: The river network file, section file, boundary file and parameter file are input into the simulation file for coordination and integration, the simulation time step is set, the simulation status is run and checked, a complete overall file is formed, and a constructed one-dimensional hydrodynamic model is obtained; the boundary file includes a time series file.

6. The method for evaluating the recharge capacity of riverside water sources based on coupled simulation of surface water and groundwater processes according to claim 5 is characterized in that: The river network file includes a mileage coordinate table of water sources, which is used to define the flow direction of the river; the section file includes the geometric dimensions of the section; the boundary file also includes external boundary conditions and internal boundary conditions; the parameter file includes the river leakage coefficient and Manning coefficient.

7. The method for evaluating the recharge capacity of riverside water sources based on coupled simulation of surface water and groundwater processes according to claim 5 is characterized in that: Both the external boundary conditions and the internal boundary conditions include boundaries and corresponding condition values; wherein the external boundary includes the starting point, the end point and the end point of the sewer outlet of the river; the internal boundary includes the places where precipitation inflows, factory drainage and water intake of the water plant are located; and the condition value adopts any one of a constant value, time-varying data and periodic data.

8. The method for evaluating the recharge capacity of riverside water sources based on surface water-groundwater process coupling simulation according to claim 1 is characterized in that: The key drivers are Huayuankou flow, water level, and groundwater extraction and groundwater levels in the southern peripheral aquifer.

9. The method for evaluating the recharge capacity of riverside water sources based on surface water-groundwater process coupling simulation according to claim 1 is characterized in that: The calculation formula of the replenishment contribution is: G=B / Z×100% In the formula, G is the contribution of the water source, %; B is the recharge of various items, including vertical recharge of groundwater from precipitation and evaporation, boundary inflow recharge and lateral seepage recharge from the Yellow River; Z is the total recharge of the water source.

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