A method for quantifying river-groundwater response and connectivity based on event scale

Abstract

This paper discloses a method for quantifying river-groundwater response and connectivity at an event scale. The method involves: acquiring time series monitoring data on rainfall, river water levels, and groundwater levels in a study area; identifying independent precipitation events; identifying effective runoff response events and calculating and quantifying the characteristics of the river response at the event scale; identifying and classifying effective groundwater response events and calculating and quantifying the characteristics of the groundwater response at the event scale; and calculating the time lag between the peaks of the river and groundwater responses to construct a dynamic connectivity index. This method overcomes the limitations of traditional steady-state analysis methods, enabling high-temporal resolution dynamic response characterization and connectivity assessment. It is highly versatile and scalable, capable of systematically revealing the event-driven coupling process between rivers and groundwater, and is suitable for water resource assessment and connectivity diagnostic analysis in regions with complex climatic and geological conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogeology and watershed hydrological process analysis, and particularly relates to a method for quantifying river-groundwater response and its connectivity based on event scale. Background Art

[0002] The dynamic interaction between rivers and groundwater systems is central to understanding the hydrological cycle within a river basin, profoundly impacting water resource regulation, water environment protection, and ecosystem sustainability. In particular, in climate transition zones, high-altitude mountainous areas, or regions with complex hydrogeological conditions, characterized by dramatic climate variability, frequent extreme precipitation events, and highly nonlinear hydrological responses, the coupled river-groundwater relationship is more abrupt and time-varying. These characteristics pose significant challenges to the understanding and regulation of river basin hydrological processes and severely constrain traditional hydrological analysis methods.

[0003] Most existing methods for identifying and analyzing river-groundwater connectivity are based on steady-state assumptions, typically relying on water level differences between river and groundwater, comparisons of hydrochemical characteristics, or numerical simulations based on long-term average conditions. However, such methods struggle to capture the dynamics of system responses driven by climate, particularly the coordinated response patterns and response lags between river and groundwater systems at the scale of a single precipitation event. Under complex geological and climatic settings, the system's non-steady-state behavior becomes more pronounced, and the empirical thresholds or fuzzy classification criteria commonly used in traditional methods are ill-suited to addressing such rapidly changing, spatially heterogeneous coupled systems. Therefore, it is urgent to develop new methods that can identify event-driven responses at high temporal resolution and systematically quantify the dynamic evolution of river-groundwater connectivity. This approach would overcome the limitations of traditional steady-state frameworks and enhance adaptability and analytical power in extreme climates and complex geological environments. Summary of the Invention

[0004] In response to the problems that existing river-groundwater connectivity analysis methods generally rely on steady-state assumptions, have difficulty in capturing non-steady-state dynamic processes, and lack event-scale quantitative analysis capabilities, the present invention provides a river-groundwater response and connectivity quantification method based on event scale.

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

[0006] A method for quantifying river-groundwater response based on event scale, characterized by comprising the following steps:

[0007] Step S1: Obtain the time series monitoring data of rainfall, river water level and groundwater level in the study area, which are defined as P ( t ), H s (t )and H g ( t );

[0008] Step S2: Based on the double threshold criterion, the rainfall time series P ( t ) to identify independent precipitation events;

[0009] Step S3: For independent precipitation events i , by setting the search window to construct the river level time series under this independent precipitation event H s ( t ) (i) , digital filtering is used to H s ( t ) (i) Perform baseflow segmentation to extract effective runoff response events and calculate characteristics that quantify event-scale river responses, including response initiation time. , Response peak time and response amplitude ;

[0010] Step S4: For independent precipitation events i , by setting the search window to construct the groundwater level time series under this independent precipitation event H g ( t ) (i) , identify and classify effective groundwater response events, and calculate and quantify the characteristics of groundwater response at the event scale, including the time it takes to initiate the groundwater response , Response peak time and response amplitude .

[0011] For each identified independent precipitation event i , and the total rainfall (TP (i) Duration of precipitation (i) ), average precipitation intensity (PIA (i) ) and maximum precipitation intensity (PIM (i) ) to quantify the characteristics of precipitation events, and the calculation formula is as follows:

[0012]

[0013] The characteristics of the precipitation event can be further combined with the river-groundwater connectivity calculated subsequently by the present invention to analyze the relationship between the river-groundwater connectivity of a certain event and the characteristics of the precipitation event.

[0014] Furthermore, the method for identifying independent precipitation events in step S2 includes:

[0015] For rainfall time series data P ( t ), define a continuous time period [ t start , t end ] is a candidate precipitation event interval, and the time step is 1 hour. The necessary conditions that must be met simultaneously for this time period to be judged as an independent precipitation event are: (1) total rainfall ; (2) End time of precipitation event The start time of the next precipitation event between P ( t ) < 0.1 mm / h, and there is a time interval of not less than 12 hours.

[0016] Furthermore, the method for identifying effective runoff response events in step S3 is:

[0017] Step S3.1: Based on i The starting time of a precipitation event , construct the river water level series under this precipitation event H s ( t ) (i) , if the next precipitation event starts at Appears in Before, ,otherwise ;

[0018] Step S3.2: Based on the determined H s ( t ) (i) , using digital filtering method to calculate the base current timing H base ( t ) (i) , and its upper confidence limit H base,95% ( t ) (i) , define the response start time as the earliest time that satisfies the following formula:

[0019] ;

[0020] in, H s ( t ) (i) For the i River level time series under a precipitation event; For the i River level time series of effective river response events in independent precipitation events; H base ( t ) (i) For H s ( t ) (i) The base flow water level time series obtained after base flow segmentation; H base,95% ( t ) (i) Base flow water level time series H base ( t ) (i) The upper limit of the confidence interval of ;

[0021] If this moment exists, it is considered that there is an effective river response, otherwise it is considered that this precipitation event has not triggered a river response; if an effective river response event is identified in step S3.2, the characteristics of the quantified event-scale river response are further calculated.

[0022] The process of calculating baseflow time series using digital filtering is a common method for baseflow separation. In this approach, a recursive digital filtering algorithm is used to process the river level time series and extract its slowly varying background component to eliminate interference caused by natural fluctuations in river levels and accurately identify effective responses triggered by precipitation events.

[0023] The calculation of the upper confidence limit of baseflow is based on the classic confidence interval estimation method. The upper confidence limit is obtained by inferring the sample mean and standard error of the baseflow sequence. It is used to statistically define the baseflow fluctuation range and serve as the threshold basis for identifying effective response events.

[0024] Furthermore, the time taken for the river response to start in step S3 is , Response peak time and response amplitude Together they characterize the river response behavior triggered by precipitation events, and the calculation formula is as follows:

[0025] ;

[0026] Where, For the i The starting time of the river response of the independent precipitation event (determined by step S3.2); The water level sequence is the peak moment of river response H s ( t ) (i) The moment when the maximum value is reached is the peak moment of response; Indicates the i Under this precipitation event, the river Water level at the moment; Indicates the i Under this precipitation event, the river Water level at the moment.

[0027] Furthermore, the method for identifying and classifying effective launching response events in step S4 is:

[0028] Step S4.1: Identify the types of phreatic and confined water responses based on i The starting time of a precipitation event , construct the groundwater depth sequence of the phreatic aquifer under this independent precipitation event H g_p ( t ) (i) and the time series of the piezometric head in the confined aquifer H g_c ( t ) (i) , if the next precipitation event starts at Appears in Before, ,otherwise ;

[0029] Step S4.2: Based on the determined H g_p ( t ) (i) and H g_c ( t ) (i) , based on the following method, groundwater response events are identified and divided into three response types, and the groundwater response starting time is determined by classification :

[0030] (1) Delayed rise response: If the groundwater level drops or remains stable at the beginning of a precipitation event and then begins to rise, the definition is for The first local minimum of the groundwater level satisfies:

[0031] ;

[0032] in, Indicates the i Under a rainfall event, groundwater Water level at the moment; represents the unit time step;

[0033] (2) Continuous rising response: If The groundwater level is already rising, i.e. , it is determined to be a response that continues the previous event, then define

[0034] for When the rate of groundwater level rise begins to increase for the first time, the following conditions are met:

[0035] ;

[0036] (3) No response: If the groundwater level does not rise significantly or continues to fall, it is defined that this precipitation event does not trigger a groundwater response;

[0037] If an effective groundwater response event is identified in step S4.2, the characteristics of the quantified event-scale groundwater response are further calculated.

[0038] Furthermore, the groundwater response start-up time in step S4 is , Response peak time and response amplitude Together they characterize the groundwater response behavior triggered by precipitation events, and the calculation formula is as follows:

[0039] ;

[0040] Where, For the i The peak moment of groundwater response in a precipitation event; is the moment when the groundwater level reaches its highest value in the i-th independent precipitation event; Indicates the groundwater level in the i-th independent precipitation event Water level at the moment; Indicates the i Groundwater in an independent precipitation event Water level at the moment.

[0041] The response of rivers and groundwater to precipitation can be measured along two core dimensions: temporal characteristics and response intensity. The three metrics selected in this method—response onset time, response peak time, and response amplitude—quantify the response process along these two dimensions.

[0042] The response start time is used to measure the time required for the system to start responding, the response peak time represents the time required from the occurrence of a precipitation event to the system reaching its most active state, and the response amplitude quantifies the intensity of the system's response to a precipitation event, that is, the amplitude of the change in "quantity".

[0043] A method for quantifying river-groundwater connectivity based on an event scale, further comprising step S5:

[0044] Based on the firsti Peak time of river response corresponding to a precipitation event and groundwater response peak moment , the river-groundwater connectivity index for this event is defined as:

[0045] ;

[0046] Where, Indicates the i The lag time between river and groundwater responses to a precipitation event, Smaller values ​​indicate more synchronous river-groundwater responses and stronger hydraulic connectivity.

[0047] Furthermore, based on the relative relationship between the peak response time of the river and the groundwater, the first i Field events are divided into two typical connectivity patterns: (1) Pattern 1: , characterizing the river's priority response type; (2) Mode 2: , characterizing the groundwater priority response type.

[0048] In this invention, the river-groundwater hydraulic connectivity index It is the peak moment of response of rivers and groundwater to each rainfall event. t peak Calculated (Formula 14), where: Extracted by step S3.3; groundwater Extracted via step S4.3. t peak It represents the moment when the river or groundwater system responds most strongly and actively to the precipitation event. It is the point when the river and groundwater system reaches the maximum hydrological response driven by the precipitation event. t rise compared to, t peak The time has integrated the comprehensive effects of multiple physical processes including infiltration, retention, confluence, and transmission paths, and can reflect the actual connectivity efficiency within the river-groundwater system.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. This method breaks through the limitation of traditional connectivity analysis that relies on steady-state assumptions. It can identify the coupling relationship between rivers and groundwater in non-steady-state, fast-responding hydrological processes. It is suitable for analyzing hydrological processes in areas with strong climate variability or frequent extreme events.

[0051] 2. The present invention constructs a characteristic indicator system for river and groundwater event responses, including multiple dimensions such as response start-up time, peak time, and response amplitude, to effectively quantify the coordinated response process of different water bodies under a single precipitation event, overcoming the shortcomings of traditional methods that rely on long-term average indicators and lack process sensitivity.

[0052] 3. The present invention introduces the response lag time of river and groundwater T lag As a dynamic connectivity index, it converts the temporal synchronization of the two into a quantifiable indicator, providing a systematic and objective method for measuring hydraulic connectivity, replacing previous indirect analysis methods that rely on empirical judgment or water chemical differences.

[0053] 4. The event-scale response and connectivity analysis method provided by the present invention has good versatility and scalability. It relies only on basic hydrological monitoring data and controllable parameter settings, and does not rely on complex models or subjective assumptions. It is suitable for rapid identification and classification analysis of connectivity under different hydrogeological backgrounds and climatic conditions.

[0054] 5. By identifying and classifying river-groundwater response patterns, the present invention can systematically reveal the coupling process of rivers and groundwater driven by events, and reveal the time-varying and asymmetric nature of connectivity relationships under different events. This can be used for in-depth analysis of the connectivity evolution mechanism, and provide technical support and theoretical basis for river basin water resources management, hydrological response prediction, and ecological regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 Schematic diagram of the process of the present invention;

[0056] Figure 2 The time series data of precipitation, river flow and groundwater in the embodiment of the present invention;

[0057] Figure 3 Schematic diagram for independent precipitation event detection and definition;

[0058] Figure 4 Schematic diagram of event-scale river response identification and quantification, where a is the schematic diagram of river response event quantification, and b is the schematic diagram of no effective river response event;

[0059] Figure 5 This is a quantitative diagram of the delayed rising response in the event-scale groundwater response classification;

[0060] Figure 6 This is a quantitative diagram of the sustained rise response in the event-scale groundwater response classification;

[0061] Figure 7 This is a schematic diagram of the untriggered effective groundwater response classification at the event scale;

[0062] Figure 8 Statistics of quantitative results of river and groundwater responses in different seasons, where a is the time taken for the response to start, b is the time taken for the response to reach its peak, and c is the response amplitude;

[0063] Figure 9 Schematic diagram of event-scale river-groundwater connectivity pattern 1 and connectivity quantification;

[0064] Figure 10 Schematic diagram of event-scale river-groundwater connectivity pattern 2 and connectivity quantification;

[0065] Figure 11 The river-groundwater connectivity patterns and their connectivity dynamics. DETAILED DESCRIPTION

[0066] To more clearly understand the technical solution of the present invention, the event-scale-based river-groundwater response and connectivity quantification method described in the present invention are described in detail below with reference to the embodiments and drawings. However, the scope of protection of the present invention is not limited to the embodiments.

[0067] Example 1:

[0068] This example selects the Tianyu River Basin, located at the northern foot of the Qinling Mountains in China, as the study area. This region lies within the climatic transition zone where the westerly winds meet the East Asian monsoon, and has a warm temperate semi-humid continental monsoon climate. It exhibits typical warm temperate semi-humid continental monsoon climate characteristics, with significant seasonal variations, strong interannual fluctuations, and frequent extreme precipitation events. This region is typical and representative for conducting event-scale hydrological response research. The main water system in the study area is the Tianyu River, which originates in the Qinling Mountains. Within the mountains, the river extends for approximately 36 km, extending for approximately 12 km beyond the mountains before merging into the Heihe River and, through the Heihe River, into the Weihe River. The river flows through a mountainous region, a piedmont alluvial fan, and a plain terrace. The terrain is highly undulating and the geological structure is complex. The surface and groundwater systems exhibit significant nonlinear and dynamic coupling characteristics in both spatial distribution and hydraulic response, making it a suitable candidate for the event-scale response and connectivity analysis described in this invention.

[0069] In this embodiment, if Figure 1 As shown in Figure 2, the event-scale-based river-groundwater response quantification method includes the following steps:

[0070] Step S1: Collect the time series monitoring data of rainfall, river water level and groundwater in the study area from 2017 to 2024, where groundwater includes the time series data of groundwater depth in the phreatic aquifer and water head in the piezometric pipe of the confined aquifer. All data are processed by outlier removal and interpolation, and the constructed time series data is as follows: Figure 2 As shown, the uniform time step is Δt=1h.

[0071] Step S2: Based on the double threshold standard, Figure 2 The precipitation time series shown P ( t ) to identify independent precipitation events and calculate the characteristic parameters of independent precipitation events, as shown in the schematic diagram Figure 3 shown.

[0072] For the rainfall time series data from 2017 to 2024 in the study area, a total of 252 independent precipitation events were identified and their characteristic parameters are shown in Table 1.

[0073] Table 1 Independent precipitation events and their characteristics

[0074]

[0075] Step S3: For the 252 independent precipitation events determined in step S2, set the search window in sequence to construct the river water level time series under the corresponding events H s ( t ) (i) , digital filtering is used to H s ( t ) (i) Perform base flow segmentation to extract effective runoff response events and calculate the response start time , Response peak time and response amplitude To quantify the river response characteristics under the corresponding precipitation events, the schematic diagram is as follows Figure 4 As shown in a and b.

[0076] In this embodiment, 141 valid river response events are determined through step S3.

[0077] Step S4: For the 252 precipitation events determined in step S2, identify the response types of phreatic and confined water, and set the search window in sequence to construct the groundwater depth sequence of the phreatic aquifer under the corresponding events. H g_p ( t ) (i) and the time series of the piezometric head in the confined aquifer H g_c ( t ) (i) , calculate the start-up time of groundwater response in different aquifers respectively , Response peak time and response amplitude To quantify the event-scale groundwater response characteristics, the schematic diagram is as follows Figure 5 、 6 , as shown in 7.

[0078] In this embodiment, 174 valid phreatic aquifer response events and 178 valid confined aquifer response events are identified in step S4. The quantitative results of the response characteristics are as follows: Figure 8 As shown in a, b, and c.

[0079] Figure 8 The statistical results of the quantitative response characteristics of rivers, unconfined aquifers and confined aquifers in the study area of ​​this embodiment of the present invention are presented and classified according to different seasons. Figure 8 It can be seen that rivers and groundwater systems exhibit significant seasonal differences in response onset time, response peak time, and response amplitude. These results verify that the event-scale response identification and quantification method constructed in this paper can accurately capture the response behavior of rivers and different types of groundwater systems under complex climatic and hydrogeological conditions.

[0080] Example 2:

[0081] Based on Example 1, continue with step S5: calculate the peak time lag of river and groundwater response T lag (i) , construct the river-groundwater dynamic connectivity index, and divide the connectivity patterns under each event based on the temporal relationship between river and groundwater responses, as shown in the schematic diagram Figure 9 、 10 shown.

[0082] Based on the first i Peak time of river response corresponding to a precipitation event and groundwater response peak moment The connectivity indices of the river-unconfined aquifer and river-confined aquifer of the event are calculated by the following formulas:

[0083]

[0084] Figure 11 The quantitative results of river-groundwater connectivity are shown, and the continuous distribution in time can be seen. The changes in the dynamic connectivity index of river-unconfined aquifer and river-confined aquifer under different precipitation events and their connectivity patterns can be seen. Figure 11 The size of the circles represents the strength of connectivity, the color of the circles (red / black) represents different connectivity patterns, and the triangles represent that the river and groundwater do not respond to the event, that is, they are not connected.

[0085] from Figure 11 It can be seen that the connectivity between the two types of groundwater systems and rivers shows high time-variability and event-dependence. Figure 11The connectivity index shown in the article is based on the event-scale response feature extraction method constructed by the present invention. It realizes quantitative calculation by integrating the response characteristics of rivers and groundwater, and effectively reflects the degree and pattern type of coordinated response between rivers and different types of groundwater during the event process.

[0086] In summary, the present invention constructs a hydrological response analysis framework driven by precipitation events, identifies the coordinated response characteristics of rivers and groundwater systems to a single precipitation event from high-temporal-resolution monitoring data, realizes high-temporal-resolution dynamic response characteristics and connectivity assessment, and then quantifies the hydraulic connectivity between the two and its evolution law. It is suitable for water resource assessment and connectivity diagnostic analysis in areas with complex climate-geological conditions.

[0087] The above is only a specific implementation example of the present invention in a specific research basin, which is used to illustrate the principles and technical effects of the present invention and to help understand the core idea of ​​the present invention. However, it should be understood that the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, without departing from the purpose of the present invention, equivalent replacements, modifications or other forms of technical solutions made based on the concept of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for quantifying river-groundwater responses based on event scale, characterized by: The following steps are involved: Step S1: Obtain the time series monitoring data of rainfall, river water level and groundwater level in the study area, which are defined as P ( t ), H s ( t )and H g ( t ); Step S2: Based on the double threshold criterion, the rainfall time series P ( t ) to identify independent precipitation events; Step S3: For independent precipitation events i , by setting the search window to construct the river level time series under this independent precipitation event H s ( t ) (i) , digital filtering is used to H s ( t ) (i) Perform baseflow segmentation to extract effective runoff response events and calculate characteristics that quantify event-scale river responses, including response initiation time. , Response peak time and response amplitude ; Methods for identifying effective runoff response events are: Step S3.1: Based on i The starting time of a precipitation event , construct the river water level series under this precipitation event H s ( t ) (i) , if the next precipitation event starts at Appears in Before, ,otherwise ; Step S3.2: Based on the determined H s ( t ) (i) , using digital filtering method to calculate the base current timing H base ( t ) (i) , and its upper confidence limit H base,95% ( t ) (i) , define the response start time as the earliest time that satisfies the following formula: ； in, H s ( t ) (i) For the i River level time series under a precipitation event; For the i River level time series of effective river response events in independent precipitation events; H base ( t ) (i) For H s ( t ) (i) The base flow water level time series obtained after base flow segmentation; H base,95% ( t ) (i) is the base flow water level time series H base ( t ) (i) The upper limit of the confidence interval of ; If this moment exists, it is considered that there is a valid river response, otherwise it is considered that this precipitation event has not triggered a river response; If a valid river response event is identified in step S3.2, the characteristics of the quantified event-scale river response are further calculated; Step S4: For independent precipitation events i , by setting the search window to construct the groundwater level time series under this independent precipitation event H g ( t ) (i) , identify and classify effective groundwater response events, and calculate and quantify the characteristics of groundwater response at the event scale, including the time it takes to initiate the groundwater response , Response peak time and response amplitude .

2. The event-scale-based river-groundwater response quantification method according to claim 1, characterized in that: The method for identifying independent precipitation events in step S2 includes: For rainfall time series data P ( t ), define a continuous time period [ t start , t end ] is a candidate precipitation event interval, and the time step is 1 hour. The necessary conditions that must be met simultaneously for this time period to be judged as an independent precipitation event are: (1) total rainfall ; (2) End time of precipitation event The start time of the next precipitation event between P ( t ) < 0.1 mm / h with a time interval of not less than 12 hours.

3. The event-scale-based river-groundwater response quantification method according to claim 1, characterized in that: In step S3, the time it takes to start the river response , Response peak time and response amplitude Together they characterize the river response behavior triggered by precipitation events, and the calculation formula is as follows: ； Where, For the i The peak moment of river response in a precipitation event; For the i The starting time of river response to an independent precipitation event; Indicates the i Under this precipitation event, the river Water level at the moment; Indicates the i Under this precipitation event, the river Water level at the moment.

4. The event-scale-based river-groundwater response quantification method according to claim 1, characterized in that: In step S4, effective launching response events are identified and the response types are classified: Step S4.1: Identify the types of phreatic and confined water responses based on i The starting time of a precipitation event , construct the groundwater depth sequence of the phreatic aquifer under this independent precipitation event H g_p ( t ) (i) and the time series of the piezometric head in the confined aquifer H g_c ( t ) (i) , if the next precipitation event starts at Appears in Before, ,otherwise ; Step S4.2: Based on the determined H g_p ( t ) (i) and H g_c ( t ) (i) , based on the following method, groundwater response events are identified and divided into three response types, and the groundwater response starting time is determined by classification : (1) Delayed rise response: If the groundwater level drops or remains stable at the beginning of a precipitation event and then begins to rise, the definition is for The first local minimum of the groundwater level satisfies: ； in, Indicates the i Under a rainfall event, groundwater Water level at the moment; represents the unit time step; (2) Continuous rising response: If The groundwater level is already rising, i.e. , it is determined to be a response that continues the previous event, then define for When the rate of groundwater level rise begins to increase for the first time, the following conditions are met: ； (3) No response: If the groundwater level does not rise significantly or continues to fall, it is defined that this precipitation event does not trigger a groundwater response; If an effective groundwater response event is identified in step S4.2, the characteristics of the quantified event-scale groundwater response are further calculated.

5. The event-scale-based river-groundwater response quantification method according to claim 4, characterized in that: Time taken to start groundwater response in step S4 , Response peak time and response amplitude Together they characterize the groundwater response behavior triggered by precipitation events, and the calculation formula is as follows: ； Where, For the i The peak moment of groundwater response in a precipitation event; is the moment when the groundwater level reaches its highest value in the i-th independent precipitation event; Indicates the groundwater level in the i-th independent precipitation event Water level at the moment; Indicates the i Groundwater in an independent precipitation event Water level at the moment.

6. A method for quantifying river-groundwater connectivity based on an event scale, based on the method for quantifying river-groundwater response based on an event scale according to claim 1, characterized in that: Also includes: Step S5: Calculate the peak time lag of river and groundwater response T lag (i) , construct a dynamic connectivity index, including: Based on the first i Peak time of river response corresponding to a precipitation event and groundwater response peak moment , the river-groundwater connectivity index for this event is defined as: ； Where, Indicates the i The lag time between river and groundwater responses to a precipitation event, Smaller values ​​indicate more synchronous river-groundwater responses and stronger hydraulic connectivity.

7. The event-scale-based river-groundwater connectivity quantification method according to claim 6, characterized in that: Based on the relative relationship between the peak response time of river and groundwater, the i Field events are divided into two typical connectivity patterns: (1) Pattern 1: , characterizing the river's priority response type; (2) Mode 2: , characterizing the groundwater priority response type.

Images