Simulation and parameter inversion method and system for surface water-groundwater interaction in riparian zone

Abstract

The application relates to a simulation and parameter inversion method and system for river bank surface water-groundwater interaction, and the method comprises the following steps: a two-dimensional phreatic groundwater unsteady flow mathematical model is established; the two-dimensional phreatic groundwater unsteady flow mathematical model is solved, and a semi-analytical expression of a groundwater head and a surface water-groundwater exchange flux is derived; water level monitoring data of an aquifer to be estimated hydrogeological parameters are collected, and dimensionless monitoring water level data are obtained by dimensionless processing of water level time series of multiple monitoring holes; the semi-analytical expression and the dimensionless monitoring water level data are fitted and wired, and the parameter value corresponding to the optimal fitting curve is taken as an estimated value of the corresponding hydrogeological parameter of the aquifer as an optimal criterion that the determination coefficient between the two is minimum; the application can simultaneously depict the influence of river geometry, free surface boundary and anisotropy of the aquifer on groundwater flow and exchange process, and has the advantages of high calculation efficiency and suitability for engineering rapid evaluation.

Description

Technical Field

[0001] This invention relates to the field of riparian groundwater flow simulation and prediction technology, and more specifically, to a method and system for simulating and parameter inversion of riparian surface water-groundwater interaction. Background Technology

[0002] Quantitative prediction of groundwater level changes in riparian zones is of great significance for water resource management, ecological environment protection, and pollution risk assessment. External driving conditions such as floods, tides, and water level fluctuations cause frequent water exchange between rivers and groundwater, which in turn affects the dynamic response characteristics of riparian groundwater systems. Traditional groundwater simulation methods are mainly based on numerical models, which can handle complex boundaries and heterogeneous conditions, but they suffer from high computational costs and difficulties in parameter sensitivity analysis, making it difficult to meet the needs of rapid engineering assessment.

[0003] To improve computational efficiency, analytical models are widely used for groundwater response analysis in riparian zones. However, existing analytical models are typically based on the assumption that the river completely penetrates the aquifer, simplifying the river boundary to a constant head or mixed boundary condition, and neglecting the influence of river geometry (such as river width and depth) on the groundwater flow process. Under actual natural conditions, especially in areas with significant sedimentation in the downstream of rivers, rivers often do not completely incise the aquifer, forming a non-deeply incised river structure. In this case, a certain thickness of aquifer medium still exists at the bottom of the river, making the hydraulic connection between the river and groundwater more complex. The traditional deep-incised river assumption is difficult to accurately describe the groundwater response process under such conditions.

[0004] Furthermore, existing models typically employ simplified boundary or overall equivalent treatment methods when dealing with the boundary area between the river lateral side and the riverbed, making it difficult to reflect local hydraulic characteristics differences. At the same time, the riparian groundwater system is also affected by the free surface boundary and the anisotropy of the aquifer. Different regions exhibit significant differences in their sensitivity to controlling factors. The aquifer on the river lateral side is mainly regulated by the free surface boundary, while the aquifer at the riverbed is more controlled by anisotropy. Existing models cannot simultaneously consider the coupling effects of these multiple factors.

[0005] Therefore, it is necessary to propose a groundwater simulation method applicable to non-deep river conditions that can simultaneously consider river geometry, free surface boundaries, and aquifer anisotropy, and improve the prediction accuracy of groundwater level and surface water-groundwater exchange flux while ensuring computational efficiency, so as to meet the needs of engineering applications. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for simulating and parameter inversion of the interaction between surface water and groundwater in riparian zones, and to provide a system for simulating and parameter inversion of the interaction between surface water and groundwater in riparian zones, in view of the above-mentioned defects of the prior art.

[0007] The technical solution adopted by this invention to solve its technical problem is: A method for simulating and retrieving parameters of surface water-groundwater interaction in riparian zones is constructed, comprising the following steps: A two-dimensional mathematical model of unsteady flow of unconfined groundwater is established under the condition that the river does not completely penetrate the aquifer, taking into account the geometric characteristics of the river's width and depth. A two-dimensional mathematical model of unsteady flow of unconfined groundwater is solved by Laplace transform, integral transform and discretization method, and semi-analytical expressions for groundwater head and surface water-groundwater exchange flux are derived. Collect aquifer water level monitoring data for hydrogeological parameters to be estimated, and perform dimensionless conversion on the water level time series of multiple monitoring wells to obtain dimensionless monitoring water level data; The semi-analytical expression is fitted with dimensionless monitoring water level data, and the minimum determination coefficient between the two is used as the optimal criterion. The parameter values ​​corresponding to the optimal fitted curve are selected as the estimated values ​​of the corresponding hydrogeological parameters of the aquifer.

[0008] The method for simulating and inverting parameters of riparian surface water-groundwater interaction described in this invention, wherein the mathematical model for unsteady groundwater flow is a two-dimensional saturated zone coupled profile model of a near-river unconfined aquifer, and must satisfy the following conditions: 1) Take the horizontal right direction as the positive direction, and the zero point is located at the intersection of the left boundary of the river and the bottom plate of the aquifer; 2) Initially, both the saturation zone and the river level are 0. 3) The river does not completely penetrate the entire aquifer. The aquifer is divided into two parts: the aquifer outside the river and the aquifer at the bottom of the river, with the left side of the river as the boundary. 4) The saturated zone is a homogeneous anisotropic medium in which water flow is a two-dimensional profile flow and its permeability coefficient does not change with time. 5) There are no other sources of water besides river water.

[0009] The method for simulating and inverting parameters of riparian surface water-groundwater interaction described in this invention, wherein the two-dimensional unsteady flow mathematical model of unconfined groundwater and its boundary conditions adopt the following formula: , (1a) , (1b) (1c) , (1d) , (1e) , (1f) The governing equations and boundary value conditions for the aquifer at the bottom of the river are given by the following formulas: ,0 (2a) , (2b) , (2c) , (2d) , (2e) , (2f) The aquifer on the left side of the river and the aquifer at the bottom of the river can be coupled through interface conditions of equal flow and equal drawdown, using the formula: , (3a) , (3b) In the formula, and These are the horizontal and vertical permeability coefficients, respectively. For water storage rate, For water supply degree; This refers to the groundwater drawdown at the boundary between the aquifer on the left side of the river and the aquifer at the bottom of the river. To account for changes in river water level, a piecewise linear interpolation function is used: (4) A dimensionless transformation is performed on equation (4), and the dimensionless variables are defined as follows: , , , , , , , , And using the variable substitution method, let After homogenization, we get: , (5a) , (5b) (5c) , (5d) , (5e) , (5f) , (6a) , (6b) , (6c) , (6d) , (6e) , (6f) , (7a) , (7b) Based on the Laplace transform, and Transforming from the time domain to the Laplace domain, the integral can be expressed in the following form: (7c) (7d) Where the superscript of the variable - indicates the Laplace transform; Here are the Laplace transform parameters, corresponding to time t; using the Laplace transform, we obtain the new governing equations: , (8a) (8b) , (8c) , (8d) (8e) , (9a) , (9b) , (9c) , (9d) , (9e) , (10a) , (10b) The solution satisfying the boundary condition (8c) satisfies the following formula: (11a) Substituting formula (11a) into (8b), we get: (11b) Substituting formula (11a) into (8a), then multiplying both sides of the equation by... , and in Integrating from 0 to 1 in the direction of 0 yields the following formula: , (12a) , (12b) (12c) In the formula, , ; The general solution of formula (12a) has the following form: (12d) In the formula Substituting formulas (12b) and (12c) into formula (12d), the coefficients can be obtained. and They are respectively: (12e) (12f) In the formula, , ; The solution that satisfies boundary condition (9b) has the following form: (13a) Substituting formula (13a) into formula (9d), we get: (13b) Substituting formula (13a) into (9a), then multiplying both sides of the equation by... , and in Direction 0 to Integrating, we obtain the following formula: , (14a) , (14b) , (14c) In the formula, , ; The general solution of formula (14a) has the following form: (14d) In the formula , Substituting formulas (14b) and (14c) into formula (14d), the coefficients can be obtained. and They are respectively: (14e) (14f) In the formula, , At this point, the side of the river in the model and the bottom of the river The solutions for surface water-groundwater interaction in the Laplace domain are as follows: (15a) (15b) coefficient , , and There are unknown variables in the integral terms. Using a discrete method, the boundary conditions of equation (10a) are used to solve the problem, dividing the open segment length into M segments of length. Discrete elements, and assume depth of cut within each element. Given a uniform distribution, replacing the integral with a summation, we obtain: (16a) (16b) set up , Then we have: (16c) (16d) By employing a discretization method and assuming that the average flow rates inside and outside each unit segment at the interface between the aquifer on the left side of the river and the aquifer at the bottom of the river are equal, the flow rate given by equation (10a) in the... The boundary conditions at the given location are rewritten as follows: (17) Substituting formulas (15c) and (15d) into (16), we get: (18a) In the formula: (18b) (18c) In the formula, , ; at this time It can be estimated using the following formula (19) In the formula For matrix The inverse matrix; Substitution coefficient , , and The changes in aquifer water levels at the bottom and sides of the river and the interaction between the river and groundwater are obtained.

[0010] The method for simulating and inverting parameters of surface water-groundwater interaction in riparian zones as described in this invention includes hydrogeological data comprising water level data and time series data of water level changes from site experimental monitoring wells.

[0011] The method for simulating and inverting parameters of riparian surface water-groundwater interaction described in this invention includes the following dimensionless processing of aquifer water level monitoring data: The aquifer water level monitoring data and equation (4) are transformed together to obtain dimensionless monitoring water level data.

[0012] The method for simulating and inverting parameters of surface water-groundwater interaction in riparian zones as described in this invention involves fitting a semi-analytical expression to dimensionless monitoring water level data, using the minimum coefficient of determination between the two as the optimal criterion, and selecting the parameter values ​​corresponding to the optimal fitting curve as the estimated values ​​of the corresponding hydrogeological parameters of the aquifer. Plot the water level changes over time based on the monitoring data, and then use the analytical expression of water head to gradually adjust the relevant hydrogeological parameters for fitting until the analytical solution can fit the monitoring data. At this point, the parameter values ​​corresponding to the analytical solution are used to estimate the range of hydrogeological parameters in the region.

[0013] A simulation and parameter inversion system for riparian surface water-groundwater interaction is provided to implement the simulation and parameter inversion method for riparian surface water-groundwater interaction as described above. The system comprises: The model building module is used to establish a two-dimensional mathematical model of unsteady flow of unconfined groundwater under the condition that the river does not completely penetrate the aquifer, taking into account the geometric characteristics of the river's width and depth. The data processing module is used to solve the two-dimensional unsteady flow mathematical model of unconfined groundwater using Laplace transform, integral transform and discretization method, and to derive semi-analytical expressions for groundwater head and surface water-groundwater exchange flux. The data acquisition module is used to collect aquifer water level monitoring data for hydrogeological parameters to be estimated, and to perform dimensionless conversion on the water level time series of multiple monitoring wells to obtain dimensionless monitoring water level data. The fitting curve module is used to fit the semi-analytical expression with the dimensionless monitoring water level data. The minimum determination coefficient between the two is used as the optimal criterion, and the parameter value corresponding to the optimal fitting curve is selected as the estimated value of the corresponding hydrogeological parameters of the aquifer.

[0014] The beneficial effects of this invention are as follows: 1. This invention breaks through the assumption in traditional analytical models that the river completely penetrates the aquifer. By introducing parameters of river width and depth, it can quantitatively analyze the influence of river geometry on groundwater response and exchange process, improve the physical realism of the model, and truly reflect the characteristics of groundwater flow under non-deeply incised river conditions. 2. This invention derives semi-analytical expressions for groundwater head and surface water-groundwater interaction flux based on mathematical analytical methods. Using existing experimental observation data, the corresponding aquifer hydrogeological parameters are determined through optimal fitting curves, linking the measured results with theoretical results and fully utilizing the value of existing data. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a flowchart of a preferred embodiment of the method for simulating and inverting parameters of riparian surface water-groundwater interaction in the present invention; Figure 2 This is a cross-sectional conceptual model diagram of saturated-unsaturated flow driven by river water ripples; Figure 3 This is a schematic diagram showing the changes in water level and interaction flux at observation points under different river depth conditions; Figure 4 This is a schematic diagram of water level changes at observation points under anisotropic conditions of the aquifer; Figure 5 This is the best-fit wiring diagram of water level changes in different monitoring wells and analytical solutions; Figure 6 This is a schematic diagram of the simulation and parameter inversion system for riparian surface water-groundwater interaction according to a preferred embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0017] The preferred embodiment of the present invention provides a method for simulating and inverting parameters of riparian surface water-groundwater interaction, such as... Figure 1 As shown, see also Figures 2-5 This includes the following steps: S01: Establish a two-dimensional mathematical model of unsteady flow of unconfined groundwater under the condition that the river does not completely penetrate the aquifer, considering the geometric characteristics of the river's width and depth; S02: The mathematical model of unsteady flow of two-dimensional unconfined groundwater is solved by Laplace transform, integral transform and discretization method, and semi-analytical expressions of groundwater head and surface water-groundwater exchange flux are derived. S03: Collect aquifer water level monitoring data for hydrogeological parameters to be estimated, and perform dimensionless conversion on the water level time series of multiple monitoring wells to obtain dimensionless monitoring water level data; S04: Fit the semi-analytical expression to the dimensionless monitoring water level data, and use the minimum determination coefficient between the two as the optimal criterion. Select the parameter value corresponding to the optimal fitting curve as the estimated value of the corresponding hydrogeological parameters of the aquifer.

[0018] like Figure 2 As shown, this invention establishes a groundwater flow model in a non-confined aquifer driven by river water level fluctuations. In this model, the right side represents the river, and the left boundary is the impermeable boundary. Based on the river's geometric characteristics, the aquifer is divided into two parts: the outer aquifer and the bottom aquifer, with the left side of the river as the boundary. Their hydraulic heads are denoted as follows: and The aquifer is an anisotropic medium. and These are the horizontal and vertical permeability coefficients, respectively. The length of the aquifer at the bottom of the river is... Depth is The length of the outer aquifer is... Depth is In the saturated zone, water flows in a two-dimensional plane, with no other sources or sinks besides river replenishment.

[0019] More specifically, the mathematical model for the unsteady flow of two-dimensional unconfined groundwater in the saturated zone and its boundary conditions are expressed by the following formula: , (1a) , (1b) (1c) , (1d) , (1e) , (1f) The governing equations and boundary value conditions for the aquifer at the bottom of the river are given by the following formulas: ,0 (2a) , (2b) , (2c) , (2d) , (2e) , (2f) The aquifer on the left side of the river and the aquifer at the bottom of the river can be coupled through interface conditions of equal flow and equal drawdown, using the formula: , (3a) , (3b) In the formula, and These are the horizontal and vertical permeability coefficients, respectively. For water storage rate, For water supply degree; This refers to the groundwater drawdown at the boundary between the aquifer on the left side of the river and the aquifer at the bottom of the river. To account for changes in river water level, a piecewise linear interpolation function is used: (4) A dimensionless transformation is performed on equation (4), and the dimensionless variables are defined as follows: , , , , , , , , And using the variable substitution method, let After homogenization, we get: , (5a) , (5b) (5c) , (5d) , (5e) , (5f) , (6a) , (6b) , (6c) , (6d) , (6e) , (6f) , (7a) , (7b) Based on the Laplace transform, and Transforming from the time domain to the Laplace domain, the integral can be expressed in the following form: (7c) (7d) Where the superscript of the variable - indicates the Laplace transform; Here are the Laplace transform parameters, corresponding to time t; using the Laplace transform, we obtain the new governing equations: , (8a) (8b) , (8c) , (8d) (8e) , (9a) , (9b) , (9c) , (9d) , (9e) , (10a) , (10b) The solution satisfying the boundary condition (8c) satisfies the following formula: (11a) Substituting formula (11a) into (8b), we get: (11b) Substituting formula (11a) into (8a), then multiplying both sides of the equation by... , and in Integrating from 0 to 1 in the direction of 0 yields the following formula: , (12a) , (12b) (12c) In the formula, , ; The general solution of formula (12a) has the following form: (12d) In the formula Substituting formulas (12b) and (12c) into formula (12d), the coefficients can be obtained. and They are respectively: (12e) (12f) In the formula, , ; The solution that satisfies boundary condition (9b) has the following form: (13a) Substituting formula (13a) into formula (9d), we get: (13b) Substituting formula (13a) into (9a), then multiplying both sides of the equation by... , and in Direction 0 to Integrating, we obtain the following formula: , (14a) , (14b) , (14c) In the formula, , ; The general solution of formula (14a) has the following form: (14d) In the formula , Substituting formulas (14b) and (14c) into formula (14d), the coefficients can be obtained. and They are respectively: (14e) (14f) In the formula, , At this point, the side of the river in the model and the bottom of the river The solutions for surface water-groundwater interaction in the Laplace domain are as follows: (15a) (15b) coefficient , , and There are unknown variables in the integral terms. Using a discrete method, the boundary conditions of equation (10a) are used to solve the problem, dividing the open segment length into M segments of length. Discrete elements, and assume depth of cut within each element. Given a uniform distribution, replacing the integral with a summation, we obtain: (16a) (16b) set up , Then we have: (16c) (16d) By employing a discretization method and assuming that the average flow rates inside and outside each unit segment at the interface between the aquifer on the left side of the river and the aquifer at the bottom of the river are equal, the flow rate given by equation (10a) in the... The boundary conditions at the given location are rewritten as follows: (17) Substituting formulas (15c) and (15d) into (16), we get: (18a) In the formula: (18b) (18c) In the formula, , ; at this time It can be estimated using the following formula (19) In the formula For matrix The inverse matrix; Substitution coefficient , , and The changes in aquifer water levels at the bottom and sides of the river and the interaction between the river and groundwater are obtained.

[0020] Hydrogeological data include water level data from site experimental monitoring wells and time series data of water level changes. Dimensionless processing of aquifer water level monitoring data is performed by transforming the aquifer water level monitoring data together with equation (4) to obtain dimensionless monitoring water level data.

[0021] The semi-analytical expression is fitted to the dimensionless monitoring water level data, and the minimum determination coefficient between the two is used as the optimal criterion. The parameter values ​​corresponding to the optimal fitted curve are selected as the estimated values ​​of the corresponding hydrogeological parameters of the aquifer. The process involves plotting the water level change over time using the monitoring data, and then using the analytical expression of the head to gradually adjust the relevant hydrogeological parameters for fitting until the analytical solution can fit the monitoring data. At this point, the parameter values ​​corresponding to the analytical solution are used to estimate the range of hydrogeological parameters in the region.

[0022] like Figure 3 As shown, this method can be used to predict the changes in water head and the changes in the interaction flux between the river and the aquifer at any observation location under different river depth conditions. Figure 3 a and 3b are observation points respectively. and A dimensionless water level time series graph. Figure 3 c and 3d are time series diagrams showing the changes in the dimensionless interaction between the river side and the surface water and groundwater on the river surface.

[0023] like Figure 4As shown, this method can be used to predict the changes in hydraulic head and the changes in the interaction flux between the river and the aquifer at any observation location under conditions of aquifer permeability anisotropy. Figure 4 a and 4b are observation points respectively. and A dimensionless water level time series graph.

[0024] The following is an explanation of the above steps using a specific simulation example based on the water level data from the site monitoring points.

[0025] Specific implementation case data: like Figure 5 As shown, using the same set of parameters, the theoretical analytical expressions for water levels at different observation points are compared and matched with monitoring data. When the optimal matching combination is found, the estimated values ​​of each hydrogeological parameter are determined as follows: , , , .

[0026] A simulation and parameter inversion system for riparian surface water-groundwater interaction is provided to implement the simulation and parameter inversion method for riparian surface water-groundwater interaction as described above. Figure 6 As shown, the system includes: Model building module 100 is used to establish a two-dimensional mathematical model of unsteady flow of unconfined groundwater under the condition that the river does not completely penetrate the aquifer, taking into account the geometric characteristics of the river's width and depth. Data processing module 101 is used to solve the two-dimensional unsteady flow mathematical model of unconfined groundwater using Laplace transform, integral transform and discretization method, and to derive semi-analytical expressions for groundwater head and surface water-groundwater exchange flux. Data acquisition module 102 is used to collect aquifer water level monitoring data of hydrogeological parameters to be estimated, and to perform dimensionless conversion on the water level time series of multiple monitoring wells to obtain dimensionless monitoring water level data. The fitting curve module 103 is used to fit the semi-analytical expression with the dimensionless monitoring water level data, and select the parameter value corresponding to the optimal fitting curve as the estimated value of the corresponding hydrogeological parameters of the aquifer, with the minimum determination coefficient between the two as the optimal criterion.

[0027] This invention considers the actual hydrogeological conditions where the river does not completely penetrate the aquifer. By introducing parameters of river width and depth, a mathematical model of river-groundwater interaction driven by changes in river water level is constructed. Semi-analytical expressions for groundwater head and surface water-groundwater interaction flux are derived using analytical mathematical methods such as Laplace transform, integral transform, and discretization. Compared with existing technologies, this invention has the following advantages: 1. This invention breaks through the assumption in traditional analytical models that the river completely penetrates the aquifer. By introducing parameters of river width and depth, it can quantitatively analyze the influence of river geometry on groundwater response and exchange process, improve the physical realism of the model, and truly reflect the characteristics of groundwater flow under non-deeply incised river conditions. 2. This invention derives semi-analytical expressions for groundwater head and surface water-groundwater interaction flux based on mathematical analytical methods. Using existing experimental observation data, the corresponding aquifer hydrogeological parameters are determined through optimal fitting curves, linking the measured results with theoretical results and fully utilizing the value of existing data.

[0028] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for simulating and retrieving parameters of surface water-groundwater interaction in riparian zones, characterized in that, Includes the following steps: A two-dimensional mathematical model of unsteady flow of unconfined groundwater is established under the condition that the river does not completely penetrate the aquifer, taking into account the geometric characteristics of the river's width and depth. A two-dimensional mathematical model of unsteady flow of unconfined groundwater is solved by Laplace transform, integral transform and discretization method, and semi-analytical expressions for groundwater head and surface water-groundwater exchange flux are derived. Collect aquifer water level monitoring data for hydrogeological parameters to be estimated, and perform dimensionless conversion on the water level time series of multiple monitoring wells to obtain dimensionless monitoring water level data; The semi-analytical expression is fitted with dimensionless monitoring water level data, and the minimum determination coefficient between the two is used as the optimal criterion. The parameter values ​​corresponding to the optimal fitted curve are selected as the estimated values ​​of the corresponding hydrogeological parameters of the aquifer.

2. The method for simulating and inverting parameters of riparian surface water-groundwater interaction according to claim 1, characterized in that, The mathematical model for unsteady groundwater flow is a two-dimensional coupled profile model of a near-river, unconfined aquifer with saturated zones, and must satisfy the following conditions: 1) Take the horizontal right direction as the positive direction, and the zero point is located at the intersection of the left boundary of the river and the bottom plate of the aquifer; 2) Initially, both the saturation zone and the river level are 0. 3) The river does not completely penetrate the entire aquifer. The aquifer is divided into two parts: the aquifer outside the river and the aquifer at the bottom of the river, with the left side of the river as the boundary. 4) The saturated zone is a homogeneous anisotropic medium in which water flow is a two-dimensional profile flow and its permeability coefficient does not change with time. 5) There are no other sources of water besides river water.

3. The method according to claim 2, wherein, The mathematical model for the unsteady flow of two-dimensional unconfined groundwater and its boundary conditions are based on the following formula: , ；(1a) , ；(1b) ；(1c) , ； (1d) , ；(1e) , ；(1f) The governing equations and boundary conditions for the aquifer at the bottom of the river are given by the following formulas: ,0 ； (2a) , ； (2b) , ；(2c) , ；(2d) , ；(2e) , ；(2f) The aquifer on the left side of the river and the aquifer at the bottom of the river can be coupled through interface conditions of equal flow and equal drawdown, using the formula: , ；(3a) ， ； (3b) where, and Kxand Kyare horizontal and vertical hydraulic conductivity, respectively, is the storage rate, is the specific yield; is the groundwater drawdown at the intersection of the left-bank aquifer and the riverbed aquifer, is the river stage variation, which is approximated by a piecewise linear interpolation function: ；(4) The dimensionless transformation is carried out on equation (4), and the dimensionless variable definition is adopted: , , , , , , , , And the variable substitution method is adopted, that is, Homogenization treatment is carried out to obtain: , ；(5a) , ； (5b) ；(5c) , ；(5d) , ；(5e) , ；(5f) , ；(6a) , ；(6b) , ；(6c) , ； (6d) , ；(6e) , ；(6f) , ；(7a) , ； (7b) Based on the Laplace transform, the and Transformed from the time domain to the Laplace domain, it is expressed in the following integral form: ；(7c) ；(7d) Where the superscript of the variable - indicates the Laplace transform; Here are the Laplace transform parameters, corresponding to time t; using the Laplace transform, we obtain the new governing equations: , ；(8a) ；(8b) , ；(8c) , ； (8d) ；(8e) , ；(9a) , ；(9b) , ；(9c) , ；(9d) , ；(9e) , ；(10a) , ；(10b) The solution satisfying the boundary condition (8c) satisfies the following formula: ；(11a) Substituting formula (11a) into (8b), we get: ；(11b) Substituting formula (11a) into (8a), then multiplying both sides of the equation by... , and in Integrating from 0 to 1 in the direction yields the following formula: , ；(12a) , ；(12b) ；(12c) In the formulae, , ; The general solution of formula (12a) has the following form: ；(12d) wherein ; substituting equations (12b) and (12c) into equation (12d), the coefficients and are respectively: ；(12e) ；(12f) In the formulae, , ; The solution that satisfies boundary condition (9b) has the following form: ；(13a) Substituting formula (13a) into formula (9d), we get: ；(13b) Substituting formula (13a) into (9a), then multiplying both sides of the equation by... , and in Direction 0 to Integrating, we obtain the following formula: , ；(14a) , ；(14b) , ；(14c) In the formulae, , ; The general solution of formula (14a) has the following form: ；(14d) In the formula , ; formula (14b) and (14c) into formula (14d), the coefficient and are respectively: ；(14e) ；(14f) In the formula, , ; at this time, the river side and river bottom of the groundwater unsteady flow mathematical model The solutions of the river surface water and groundwater interaction in the Laplace domain are respectively: ；(15a) ；(15b) coefficient , , and There are unknown variables in the integral terms. The discretization method is adopted, and the boundary conditions of equation (10a) are used to solve it, dividing the length of the open segment into M segments of length. Discrete elements, and assume depth of cut within each element. Given a uniform distribution, replacing the integral with a summation, we obtain: ；(16a) ；(16b) Let , then ；(16c) ；(16d) By employing a discretization method and assuming that the average flow rates inside and outside each unit segment at the interface between the aquifer on the left side of the river and the aquifer at the bottom of the river are equal, the flow rate given by equation (10a) in the... The boundary conditions at the given location are rewritten as follows: ；(17) Substituting formulas (15c) and (15d) into (16), we get: ；(18a) In the formula: ；(18b) ；(18c) In the formulae, , ; At this time may be estimated by the equation ；(19) where is the inverse matrix of the matrix ; substituting into the coefficients , , and gives the water level changes in the river bottom and side aquifers and the exchange between the river and the groundwater.

4. The method of claim 1, wherein, The hydrogeological data includes water level data and time series data of water level changes from the site experimental monitoring wells.

5. The method for simulating and inverting parameters of riparian surface water-groundwater interaction according to claim 1, characterized in that, Dimensionless processing of aquifer water level monitoring data was performed using: The aquifer water level monitoring data and equation (4) are transformed together to obtain dimensionless monitoring water level data.

6. The method of riverbank zone surface water-groundwater interaction simulation and parameter inversion according to claim 1, characterized in that, The process involves fitting the semi-analytical expression to the dimensionless monitoring water level data, using the minimum coefficient of determination between the two as the optimal criterion, and selecting the parameter values ​​corresponding to the optimal fitted curve as the estimated values ​​of the corresponding hydrogeological parameters of the aquifer. Plot the water level changes over time based on the monitoring data, and then use the analytical expression of water head to gradually adjust the relevant hydrogeological parameters for fitting until the analytical solution can fit the monitoring data. At this point, the parameter values ​​corresponding to the analytical solution are used to estimate the range of hydrogeological parameters in the region.

7. A riparian zone surface water-groundwater interaction simulation and parameter inversion system for implementing the riparian zone surface water-groundwater interaction simulation and parameter inversion method of any one of claims 1-6, characterized in that, The system includes: The model building module is used to establish a two-dimensional mathematical model of unsteady flow of unconfined groundwater under the condition that the river does not completely penetrate the aquifer, taking into account the geometric characteristics of the river's width and depth. The data processing module is used to solve the two-dimensional unsteady flow mathematical model of unconfined groundwater using Laplace transform, integral transform and discretization method, and to derive semi-analytical expressions for groundwater head and surface water-groundwater exchange flux. The data acquisition module is used to collect aquifer water level monitoring data for hydrogeological parameters to be estimated, and to perform dimensionless conversion on the water level time series of multiple monitoring wells to obtain dimensionless monitoring water level data. The fitting curve module is used to fit the semi-analytical expression with the dimensionless monitoring water level data. The minimum determination coefficient between the two is used as the optimal criterion, and the parameter value corresponding to the optimal fitting curve is selected as the estimated value of the corresponding hydrogeological parameters of the aquifer.

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