A method for analyzing groundwater recharge process

Abstract

The present invention discloses a method for analyzing the groundwater recharge process, which relates to the field of groundwater calculation technology. A rainfall base flow response model is obtained; the rainfall base flow response model is constructed based on the relationship between the river base flow, groundwater utilization, and base flow at the basin outlet formed by large channel preferential flow, soil preferential flow, and soil piston flow; based on the rainfall data and base flow data of the study area, the model parameters of the rainfall base flow response model are solved by genetic algorithm to obtain the target values of the model parameters in the rainfall base flow response model; according to the target values, the water retreat unit lines of the large channel preferential flow, soil preferential flow, and soil piston flow in the study area are determined; the water retreat unit lines are used to describe the groundwater recharge process in the study area. This method can accurately analyze the groundwater recharge process of large channel preferential flow, soil preferential flow, and soil piston flow in the Loess Plateau region.

Description

Technical Field

[0001] The present invention relates to the field of groundwater calculation technology, and in particular to a groundwater recharge process analysis method. Background Art

[0002] Currently, surface water resources on the Loess Plateau are scarce. Precipitation is the primary source of water recharge in the region. Shallow groundwater is the primary source of surface runoff and the freshwater resource upon which local residents depend, making it crucial for the region's sustainable socioeconomic development. A correct understanding of groundwater recharge processes (including recharge cycles, recharge modes, and their contributions) is fundamental to clarifying regional groundwater circulation mechanisms and a prerequisite for groundwater development and utilization. However, the Loess Plateau's aeration zone is deep (typically 30 to 100 m), resulting in long recharge cycles (ranging from days to decades) and diverse recharge modes (plug flow, preferential flow, or a combination of both). Accurately quantifying the processes and mechanisms of preferential and plug flow recharge is a hot topic and a challenging problem in groundwater recharge research.

[0003] In recent years, the application of stable isotope and hydrochemical tracer techniques has greatly advanced and enriched our understanding of groundwater recharge mechanisms on the Loess Plateau. Studies examining the distribution and mass balance of tracer elements in precipitation, deep soil water, and groundwater at multiple locations have been able to quantify the contributions of regional preferential flow and piston flow to groundwater recharge, but they are unable to characterize the dynamic processes of groundwater recharge. Furthermore, preferential flow at the regional scale is controlled not only by large preferential flow channels and networks, such as cracks, fissures, and pores within soil profile pores and low-lying areas and runoff pathways, but also by surface and subsurface hydrological processes. Current methods fail to effectively reflect the recharge of groundwater to groundwater through large preferential flow channels at the regional scale and are unable to characterize the dynamic processes of groundwater recharge.

[0004] Therefore, there is an urgent need for a method that can accurately analyze the groundwater recharge processes of large-channel preferential flow, soil preferential flow and soil piston flow in the Loess Plateau region. Summary of the Invention

[0005] Based on this, it is necessary to provide a groundwater recharge process analysis method to address the above technical problems. This method can accurately analyze the groundwater recharge processes of large channel preferential flow, soil preferential flow and soil piston flow in the Loess Plateau region.

[0006] The present invention adopts the following technical solutions:

[0007] The present invention provides a method for analyzing a groundwater recharge process, comprising:

[0008] Obtain a rainfall baseflow response model; the rainfall baseflow response model is constructed based on the relationship between river baseflow generated by large channel preferential flow, soil preferential flow, and soil piston flow, groundwater utilization, and baseflow at the basin outlet; the river baseflow generated by large channel preferential flow, soil preferential flow, and soil piston flow is determined based on the differences in groundwater recharge lag times for large channel preferential flow, soil preferential flow, and soil piston flow, respectively, and the unit line of water withdrawal;

[0009] Based on the rainfall data and base flow data of the study area, the model parameters of the rainfall base flow response model are solved by genetic algorithm to obtain the target values of the model parameters in the rainfall base flow response model.

[0010] Based on the target values, the unit lines of large channel preferential flow, soil preferential flow and soil piston flow in the study area are determined; the unit lines of retreat are used to describe the groundwater recharge process in the study area.

[0011] Optionally, the rainfall baseflow response model is:

[0012] ;

[0013] in, is the base flow at the basin outlet, Respectively represent the start time and end time of the large channel priority flow, express The amount of precipitation during the period, express The proportion of rainfall during the period converted into large channel priority flow, express The weight coefficient of the water withdrawal unit line formed by the preferential flow of the large channel during the period, represent the start time and end time of soil preferential flow, express Potential recharge flux of soil preferential flow during the period, for The weight coefficient of the unit line of water withdrawal formed by soil preferential flow in the time period, Represent the start time and end time of soil piston flow, for The potential groundwater recharge flux of soil piston flow during the period, for The weight coefficient of the unit line of water withdrawal formed by the soil piston flow in the time period, is the groundwater utilization, represents the lower incomplete Gamma function, Respectively Gamma function, are all model parameters of the rainfall baseflow response model.

[0014] Optionally,

[0015] ;

[0016] in, for Surface runoff during the period, is the runoff threshold, Indicates the maximum scale;

[0017] ;

[0018] Among them, the subscript Indicates agricultural, forestry and grassland, represents the potential groundwater recharge coefficient of soil preferential flow, Indicates the land use coefficient corresponding to agriculture, forestry and grassland; express The amount of precipitation during the period;

[0019] ;

[0020] in, is the potential groundwater recharge coefficient of soil piston flow, express The amount of precipitation during the period.

[0021] Optionally, based on target values, the water withdrawal unit lines of the large channel preferential flow, soil preferential flow, and soil piston flow are determined, including:

[0022] According to the target value, the weight coefficients of the unit line of water withdrawal formed by the preferential flow of the large channel in the study area, the weight coefficients of the unit line of water withdrawal formed by the preferential flow, and the weight coefficients of the unit line of water withdrawal formed by the soil piston flow are determined;

[0023] According to the weight coefficient of the water retreat unit line formed by the large channel preferential flow, the weight coefficient of the water retreat unit line formed by the preferential flow and the weight coefficient of the water retreat unit line formed by the soil piston flow in the study area, the water retreat unit lines of the large channel preferential flow, soil preferential flow and soil piston flow are determined.

[0024] Optionally, the method further includes:

[0025] Based on the unit lines of large channel preferential flow, soil preferential flow and soil piston flow in the study area, the time lag effect of base flow on large channel preferential flow, soil preferential flow and piston flow, the recharge process, and the cumulative recharge flux are determined.

[0026] The present invention provides a groundwater recharge process analysis device, comprising:

[0027] An acquisition module is used to obtain a rainfall baseflow response model. The rainfall baseflow response model is constructed based on the relationship between the river baseflow generated by large channel preferential flow, soil preferential flow, and soil piston flow, groundwater utilization, and baseflow at the basin outlet. The river baseflow generated by large channel preferential flow, soil preferential flow, and soil piston flow is determined based on the differences in the groundwater recharge lag times of large channel preferential flow, soil preferential flow, and soil piston flow, respectively, and the water withdrawal unit line.

[0028] A solution module is used to solve the model parameters of the rainfall base flow response model through a genetic algorithm based on the rainfall data and base flow data of the study area, so as to obtain the target values of the model parameters in the rainfall base flow response model;

[0029] The analytical module is used to determine the water withdrawal unit lines of large channel preferential flow, soil preferential flow, and soil piston flow in the study area based on the target values; the water withdrawal unit lines are used to describe the groundwater recharge process in the study area.

[0030] The present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned groundwater recharge process analysis method is implemented.

[0031] The present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned groundwater recharge process analysis method when executing the program.

[0032] At least one of the above technical solutions adopted by the present invention can achieve the following beneficial effects:

[0033] Based on the differences in the lag time of groundwater recharge caused by regional large-channel preferential flow, soil preferential flow, and plug flow, this study, combined with the water retreat unit line method, links the river baseflow generated by large-channel preferential flow, soil preferential flow, and soil plug flow to groundwater recharge and baseflow. A rainfall baseflow response model was constructed, and the time series of baseflow, a hydrological signal, was used to deduce the processes and mechanisms of groundwater recharge caused by preferential flow and plug flow. Compared with existing environmental isotope and hydrochemical tracer methods, this method overcomes the heterogeneity of hydrological processes, scale effects, and tracer input uncertainty. It also overcomes the difficulty in quantitatively characterizing the impact of preferential flow on groundwater recharge at the regional scale, achieving accurate analysis of the groundwater recharge processes of large-channel preferential flow, soil preferential flow, and soil plug flow in the Loess Plateau. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0035] Figure 1 A schematic flow chart of a groundwater recharge process analysis method provided by the present invention;

[0036] Figure 2 Schematic diagram of the unit line of water withdrawal for large channel preferential flow, soil preferential flow, soil piston flow, and the total unit line of water withdrawal;

[0037] Figure 3 A schematic diagram of a computer device for implementing a groundwater recharge process analysis method provided by the present invention. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Existing environmental isotope and hydrochemical tracer methods can quantify the contributions of preferential and plug flows to groundwater recharge, but these results are affected by spatial heterogeneity in land use, soil, and vegetation, and cannot characterize the processes by which preferential and plug flows recharge groundwater. Groundwater discharge (baseflow) is the primary source of river runoff in the Loess Plateau. Previous studies have shown that rainfall plays a decisive role in this process. Even though the rainfall signal becomes smoothed by the deep loess layer, groundwater and baseflow still record and inherit the characteristics of precipitation. Long-term baseflow signals within a watershed reveal regional groundwater recharge and storage characteristics, which are extremely valuable for inferring groundwater recharge processes and mechanisms. Therefore, based on the differences in the lag times of regional large-channel preferential flow, soil preferential flow, and plug flow in groundwater recharge, and combined with the receding unit line method, we link the groundwater recharge of preferential and plug flows to baseflow, constructing a rainfall-based baseflow response model. This time series of baseflow, a hydrological signal, is used to infer the processes and mechanisms of preferential and plug flow recharge. Compared with previous studies based on tracer elements, inferring the process (groundwater recharge) based on the results (baseflow) and using baseflow as a proxy is a new method to analyze the groundwater recharge process and mechanism in the Loess Plateau.

[0040] The execution subject of the method provided in the present invention can be a server set up on the business platform, or a device such as a desktop computer, a laptop computer, etc. that can execute the solution of the present invention. For the sake of convenience, the following description only takes the server as the execution subject.

[0041] The technical solutions provided by various embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] Figure 1 The figure is a flow chart of a method for analyzing a groundwater recharge process in the present invention, which specifically includes the following steps:

[0043] S101, obtain a rainfall base flow response model; the rainfall base flow response model is constructed based on the relationship between the river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow, groundwater utilization and base flow at the basin outlet; the river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow is determined based on the differences in the groundwater recharge lag time of large channel preferential flow, soil preferential flow and soil piston flow and the water retreat unit line.

[0044] First, the relationship between river baseflow, groundwater utilization, and baseflow at the basin outlet formed by large channel preferential flow, soil preferential flow, and soil piston flow can be used to construct an initial rainfall baseflow response model.

[0045] The initial rainfall base flow response model can describe the process and mechanism of groundwater recharge by large channel preferential flow, soil preferential flow and piston flow. Optionally, the initial rainfall base flow response model is:

[0046] (1);

[0047] in, is the base flow at the basin outlet; 、 、 They are the river base flow formed by the large channel preferential flow, the river base flow formed by the soil preferential flow and the river base flow formed by the soil piston flow; The units of the base flow at the basin outlet, the river base flow formed by the preferential flow in the large channel, the river base flow formed by the preferential flow in the soil, the river base flow formed by the soil piston flow and the groundwater utilization are all in millimeters.

[0048] Then, the calculation formula of river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow is substituted into the initial rainfall base flow response model to determine the rainfall base flow response model; the calculation formula of river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow is based on the difference in groundwater recharge lag time of large channel preferential flow, soil preferential flow and soil piston flow and is constructed in combination with the retreat unit line method.

[0049] Specifically, the calculation formula for large channel priority flow is:

[0050] (2);

[0051] (3);

[0052] in, Respectively represent the start time and end time of the large channel priority flow, express The amount of precipitation during the period, express The weight coefficient of the water withdrawal unit line formed by the preferential flow of the large channel during the period, that is, i Rainfall during g The proportion of large channel priority flows generated during the time period, g − i represents the number of lag periods of the preferential flow in the large channel relative to rainfall, for Surface runoff during the period, is the runoff threshold, express The proportion of rainfall during the period converted into large channel priority flow, Indicates the maximum proportion. Among them, the large channel preferential flow is mainly formed by the low-lying areas in the region and the preferential flow channels in the runoff path. When there is no surface runoff, this value is 0. As the surface runoff increases, more preferential flow channels are activated, and the proportion of rainfall converted into large channel preferential flow increases. When the surface runoff q ri Reaching runoff threshold q th When all preferential flow channels are activated, the proportion of rainfall converted into preferential flow in large channels reaches its maximum value. f max , that is, the ratio of rainfall converted into large channel preferential flow is f max The phase function.

[0053] The calculation formula of soil preferential flow is:

[0054] (4);

[0055] (5);

[0056] in, represent the start time and end time of soil preferential flow, express Potential recharge flux of soil preferential flow during the period, for The weight coefficient of the unit line of water withdrawal formed by soil preferential flow in the period, that is, j Rainfall during p The proportion of priority flows generated during a time period, p − j The number of lag periods of preferential flow relative to rainfall, subscript Representing agriculture, forestry and grassland respectively. represents the potential groundwater recharge coefficient of soil preferential flow, Indicates the land use coefficient corresponding to agriculture, forestry and grassland; express The precipitation amount during the period, in mm. For model parameters, their range can be determined through experiments or literature research, or attempts can be made to establish a multivariate statistical mathematical relationship between them and influencing factors to reduce the workload of model parameter inversion. Obtained through land use type survey statistical data or remote sensing data.

[0057] The calculation formula for soil piston flow is:

[0058] (6);

[0059] (7);

[0060] in, Represent the start time and end time of soil piston flow, for The potential groundwater recharge flux of soil piston flow during the period, for The weight coefficient of the unit line of water withdrawal formed by the soil piston flow during the period, that is, k Rainfall during w The proportion of priority flows generated during a time period, w − k represents the number of lag periods of plug flow relative to rainfall; are the potential groundwater recharge coefficients of soil piston flow, express The amount of precipitation during the period. For model parameters, their range can be determined through experiments or literature research, or attempts can be made to establish a multivariate statistical mathematical relationship between them and influencing factors to reduce the workload of model parameter inversion.

[0061] It should be noted that the amount of groundwater used It is uniform throughout the year and can be obtained from regional water resources bulletins or estimated based on population and economic data.

[0062] The aeration zone and aquifer with storage function can be regarded as a series of linear reservoirs. According to the principle of multiple ratio and superposition, the rainfall base flow response model determined by the above formula (1) to formula (7) is:

[0063] (8);

[0064] in, represents the lower incomplete Gamma function, Respectively Gamma function, are all model parameters of the rainfall baseflow response model.

[0065] S102 , based on the rainfall and baseflow data of the study area, solving the model parameters of the rainfall baseflow response model by using a genetic algorithm to obtain target values of the model parameters in the rainfall baseflow response model.

[0066] The study area can be the Loess Plateau, the rainfall data include the precipitation in each period, and the base flow data include the outlet base flow and groundwater utilization in each period.

[0067] Obtain the outlet base flow of the study area at each time period , Groundwater utilization in each period , precipitation in each period, 、 、 , using genetic algorithm to adjust the model parameters based on formula (8) 、 、 、 、 、 、 Perform optimization to obtain the optimal value of the model parameter, which is the target value of the model parameter.

[0068] S103. Determine the water withdrawal unit lines of the large channel preferential flow, soil preferential flow, and soil piston flow in the study area based on the target value; the water withdrawal unit lines are used to describe the groundwater recharge process in the study area.

[0069] Optionally, according to the target value, the water withdrawal unit lines of the large channel preferential flow, soil preferential flow and soil piston flow are determined, including: determining the weight coefficient of the water withdrawal unit line formed by the large channel preferential flow, the weight coefficient of the water withdrawal unit line formed by the preferential flow and the weight coefficient of the water withdrawal unit line formed by the soil piston flow according to the target value; determining the water withdrawal unit lines of the large channel preferential flow, soil preferential flow and soil piston flow according to the weight coefficient of the water withdrawal unit line formed by the large channel preferential flow, the weight coefficient of the water withdrawal unit line formed by the preferential flow and the weight coefficient of the water withdrawal unit line formed by the soil piston flow.

[0070] For the weight coefficients of the retreat unit line of large channel preferential flow, soil preferential flow and soil piston flow at any time period, the target values of the determined model parameters are substituted into , the obtained value is The weight coefficient of the water withdrawal unit line formed by the preferential flow of the large channel during the period; Substitute the target value of the determined model parameter into , the obtained value is The weight coefficient of the unit line of water withdrawal formed by soil preferential flow in the period is substituted into the target value of the determined model parameter. , the obtained value is The weight coefficient of the unit line of water withdrawal formed by soil plug flow in this period.

[0071] According to the weight coefficients of the water retreat unit line formed by the large channel preferential flow, the weight coefficients of the water retreat unit line formed by the preferential flow and the weight coefficients of the water retreat unit line formed by the soil piston flow in the study area, the water retreat unit lines of the large channel preferential flow, soil preferential flow and soil piston flow are drawn.

[0072] The total water retreat unit line can also be drawn based on the water retreat unit lines of large channel preferential flow, soil preferential flow and soil piston flow. The total water retreat unit line is the accumulation of the water retreat unit lines of large channel preferential flow, soil preferential flow and soil piston flow in the corresponding period.

[0073] like Figure 2 As shown, Figure 2 Schematic diagram of the unit water withdrawal lines for large channel preferential flow, soil preferential flow, soil piston flow, and the total unit water withdrawal line.

[0074] In one embodiment, the time lag effect of base flow on the macrochannel preferential flow, soil preferential flow, and plug flow, the recharge process, and the cumulative recharge flux are determined based on the retreat unit lines of the macrochannel preferential flow, soil preferential flow, and soil plug flow in the study area.

[0075] Specifically, based on the unit lines of large-channel preferential flow, soil preferential flow, and soil piston flow, the time lag effect of base flow on them and the recharge process can be obtained. By calculating their cumulative recharge flux, the contributions of the three and the dominant form of regional groundwater recharge can be clarified, thereby realizing the analysis of the groundwater recharge process and mechanism on the Loess Plateau.

[0076] Specifically, the time lag effect of large channel preferential flow, soil preferential flow, and plug flow is the time when the unit line approaches 0, that is, g -g1, p - p 1 and w - w 1; The recharge processes of large channel preferential flow, soil preferential flow, and piston flow are: 、 、 .

[0077] The cumulative recharge flux is the sum of the recharge amounts of large channel preferential flow, soil preferential flow, and piston flow in each period.

[0078] Groundwater recharge on the Loess Plateau is influenced not only by soil preferential flow and plug flow, but also by macrochannel preferential flow composed of fractures, pores, and other structures, as well as watershed characteristics. This paper utilizes temporal differences in groundwater recharge caused by regional macrochannel preferential flow, soil preferential flow, and plug flow, combined with the watershed unit line method to construct a basin rainfall baseflow response model that considers land use change. This method achieves a quantitative characterization of the preferential flow and plug flow recharge processes on the Loess Plateau. Compared with existing environmental isotope and hydrochemical tracer methods, this method overcomes the heterogeneity of hydrological processes, scale effects, and tracer input uncertainty that affect the results, and overcomes the difficulty in quantitatively characterizing the preferential flow effect on groundwater recharge processes at the regional scale. The proposed model method has clear physical significance, few parameters, and a wide range of applicability. It can be used to evaluate groundwater recharge characteristics before and after land use changes caused by human activities on the Loess Plateau. This invention has important scientific significance and value in enriching the research methods of groundwater recharge mechanisms and has important application value in ensuring regional water security, the sustainable development and utilization of groundwater resources, and serving regional ecological protection.

[0079] When applying the groundwater recharge process analysis method provided by the present invention, it is not necessary to Figure 1 The steps are executed in the order shown. The specific execution order of the steps can be determined according to needs, and the present invention does not limit this.

[0080] The above is a groundwater recharge process analysis method provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding groundwater recharge process analysis device, which includes:

[0081] The acquisition module is used to obtain the rainfall base flow response model; the rainfall base flow response model is constructed based on the relationship between the river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow, groundwater utilization and base flow at the basin outlet; the river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow is determined based on the difference in the groundwater recharge lag time of large channel preferential flow, soil preferential flow and soil piston flow and the water retreat unit line.

[0082] The solution module is used to solve the model parameters of the rainfall base flow response model through a genetic algorithm based on the rainfall data and base flow data of the study area, and obtain the target values of the model parameters in the rainfall base flow response model.

[0083] The analytical module is used to determine the water withdrawal unit lines of large channel preferential flow, soil preferential flow, and soil piston flow in the study area based on the target values; the water withdrawal unit lines are used to describe the groundwater recharge process in the study area.

[0084] The specific limitations of the groundwater recharge process analysis device can be found in the limitations of the groundwater recharge process analysis method described above and will not be repeated here. Each module in the above-mentioned groundwater recharge process analysis device can be implemented in whole or in part through software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in a computer device in software form, so that the processor can call and execute the corresponding operations of each of the above modules.

[0085] The present invention also provides a computer-readable storage medium, which stores a computer program, which can be used to execute the above Figure 1 Provided is an analytical method for the groundwater recharge process.

[0086] The present invention also provides Figure 3 The structural diagram of the computer equipment shown in FIG. Figure 3 As shown in the figure, at the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory. Of course, it may also include other hardware required for the business. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to achieve the above Figure 1 Provided is an analytical method for the groundwater recharge process.

[0087] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware using a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes in the above-described method embodiments. Any reference to memory, storage, database, or other media used in the various embodiments provided herein may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0088] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A method for analyzing groundwater recharge process, characterized in that: include: Obtaining a rainfall base flow response model; the rainfall base flow response model is constructed based on the relationship between river base flow formed by large channel preferential flow, soil preferential flow and soil piston flow, groundwater utilization, and base flow at the basin outlet; The river base flow formed by large channel preferential flow, soil preferential flow and soil plug flow is determined based on the difference in groundwater recharge lag time of large channel preferential flow, soil preferential flow and soil plug flow and the unit line of water withdrawal. Based on the rainfall data and base flow data of the study area, the model parameters of the rainfall base flow response model are solved by genetic algorithm to obtain the target values of the model parameters in the rainfall base flow response model. According to the target values, the unit lines of water withdrawal for the large channel preferential flow, soil preferential flow and soil piston flow in the study area are determined; The water withdrawal unit line is used to describe the groundwater recharge process in the study area; The rainfall base flow response model is: Among them, R e(m) is the base flow at the basin outlet, g1 and g represent the start and end time of the large channel priority flow, respectively, and P (i) represents the precipitation in period i, f 1,i It represents the proportion of rainfall in period i that is converted into large channel preferential flow, represents the weight coefficient of the water withdrawal unit line formed by the preferential flow of the large channel during period i, p1 and p represent the start time and end time of the soil preferential flow, respectively, and DP p(j) represents the potential recharge flux of soil preferential flow in period j, is the weight coefficient of the unit line of water withdrawal formed by soil preferential flow in period j, w1 and w represent the start time and end time of soil piston flow respectively, DP m(k) is the potential groundwater recharge flux of soil piston flow during period k, is the weight coefficient of the unit line of water withdrawal formed by soil piston flow in period k, R w(m) is the groundwater utilization, γ represents the lower incomplete Gamma function, Γ(n1), Γ(n2), and Γ(n3) represent the Gamma functions of n1, n2, and n3, respectively, and n1, K1, n2, K2, n3, and K3 are all model parameters of the rainfall baseflow response model; Among them, q ri is the surface runoff in period i, q th is the runoff threshold, f max Indicates the maximum scale; Where, subscript t represents agriculture, forestry and grassland, β t represents the potential groundwater recharge coefficient of soil preferential flow, η t represents the land use coefficient corresponding to agriculture, forestry and grassland; P (j) represents the precipitation in period j; Among them, λ t is the potential recharge coefficient of soil piston flow to groundwater, P (k) represents the precipitation in period k.

2. The method according to claim 1, characterized in that According to the target value, determine the water withdrawal unit line of large channel preferential flow, soil preferential flow and soil piston flow, including: According to the target value, the weight coefficients of the unit line of water withdrawal formed by the preferential flow of the large channel in the study area, the weight coefficients of the unit line of water withdrawal formed by the preferential flow, and the weight coefficients of the unit line of water withdrawal formed by the soil piston flow are determined; According to the weight coefficient of the water retreat unit line formed by the large channel preferential flow, the weight coefficient of the water retreat unit line formed by the preferential flow and the weight coefficient of the water retreat unit line formed by the soil piston flow in the study area, the water retreat unit lines of the large channel preferential flow, soil preferential flow and soil piston flow are determined.

3. The method according to claim 1, characterized in that The method further comprises: Based on the unit lines of large channel preferential flow, soil preferential flow and soil piston flow in the study area, the time lag effect of base flow on large channel preferential flow, soil preferential flow and piston flow, the recharge process, and the cumulative recharge flux are determined.

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