LU500829B1

LU500829B1 - Groundwater management method and device

Info

Publication number: LU500829B1
Application number: LU500829A
Authority: LU
Inventors: Gang Ji; Yinhui Long; Yaru Feng; Xiaomin Xu; Rui Jiao; Yanfei Zhang; Zilong Liao; Zhenhua Han; Wentao Liang; Chuanzhe Li; Ting Wang; Yingjie Cui; Yifan Song; Hualin Liu; Yongfu Wei
Original assignee: China Inst Water Resources & Hydropower Res
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-05-05

Abstract

The embodiments of the present application provide a groundwater management method and device, and the method includes: acquiring a groundwater flow numerical model established by hydrological data in the research area, where the groundwater flow numerical model is used to describe the relationship between the groundwater level in the research area and the amount of groundwater extraction and natural climate conditions; according to the groundwater flow numerical model, an iterative calculation with the maximum groundwater extraction volume as the optimization objective and the groundwater level not lower than the minimum ecological water level as the constraint condition is performed to obtain the target extraction volume of each mining well in the study area. In this embodiment, the groundwater flow numerical model can be used to accurately simulate the groundwater level, and the extraction volume is optimized with the goal of maximizing the extraction volume of groundwater.

Description

DESCRIPTION 7500829 Groundwater management method and device

TECHNICAL FIELD This application relates to the technical field of groundwater management, and specifically to a method and device for groundwater management.

BACKGROUND Groundwater is the main source of water supply. With the increase of water consumption in various regions and limited groundwater resources, excessive exploitation of groundwater will lead to a series of environmental geological problems such as water resource depletion and land subsidence. At present, there is a lack of effective management of groundwater to realize rational exploitation of groundwater.

SUMMARY The purpose of the embodiment of the application is to provide a groundwater management method and device, which can accurately simulate the groundwater level by using a groundwater flow numerical model and take the groundwater ecological level as a constraint condition. In order to provide effective management for the exploitation of groundwater in mining wells, the groundwater exploitation is optimized with the aim of maximizing the exploitation of groundwater.

In a first aspect, an embodiment of the present application provides a groundwater management method, which comprises: Acquiring a groundwater flow numerical model established by hydrological data in the study area, wherein the groundwater flow numerical model is used for describing the relationship between groundwater level, groundwater exploitation amount and natural climate conditions in the study area; According to the groundwater flow numerical model, iterative calculation is carried out with the maximum groundwater exploitation amount as the optimization objective and the groundwater level not lower than the lowest ecological water level as the constraint condition, so as to obtain the target exploitation amount of each mining well in the study area, wherein the lowest ecological water level represents the corresponding groundwater level when the water level change caused by evaporation is zero.

Co. . LU500829 In the above process, the groundwater level of each control point in the study area 1s simulated by using the groundwater flow numerical model, and the target exploitation amount of groundwater by each exploitation well is obtained on the premise of ensuring that the groundwater level of each control point is not lower than the minimum ecological water level. According to the target amount of groundwater exploitation, the dual management of water level and water quantity is realized. Meanwhile, because the optimization is aimed at maximizing the amount of groundwater exploitation in the mining well, the maximization of economic benefits of water resources is ensured.

In some implementations of the first aspect, before obtaining the numerical model of groundwater flow established by hydrological data in the study area, the method further comprises: Acquire hydrological data in the study area; According to the hydrological data, a numerical model of groundwater flow is established as follows: BR ÉTÉ 2 rt +q+Ev+P (x,y)eD,t>0 or ox\ ox) oy\ oy H(x,y,0)=H, (x,y) (x,y)eD,1=0 Hl. =H(x,y,t) (x,y)el',t>0 rl = q(x, 3,1) (x,y)el,,t>0 on |r, Among them, D is the research area, H is the groundwater level of the control point, (x, y) is the location of the mining well or control point, t is the time, E 1s the water storage parameter, T is the hydraulic conductivity, q is the amount of groundwater extracted from the mining well, EV is the evaporation discharge, P is the precipitation replenishment, H, (x, y) is the initial water level of the control point, I’, is the first type of boundary of the study area, I', is the second type of boundary of the study area, 4 (x, 3,1 ) is the water flow through the second type of boundary, q, £V,P, H,(x,y), T,and TI’, are determined by the hydrological data, E and T are determined by the hydrological data to determine initial values and are determined after model parameter tuning.

. . . . .. , LU500829 In the above process, the groundwater flow numerical model is first established, the initial parameters in the model are determined according to the hydrological data of the study area, and then the historical observation data 1s used to train the model to achieve parameter tuning, until the difference between the groundwater level calculated by the final model and the actual observed water level meets the accuracy requirements, a groundwater flow numerical model that is finally used to simulate the groundwater system is obtained.

In some implementations of the first aspect, the groundwater flow numerical model includes an artificial flow field model and a natural flow field model, the groundwater level output by the groundwater flow numerical model is obtained by superposing the first groundwater level calculated by the artificial flow field model and the second groundwater level calculated by the natural flow field model; The artificial flow field model is: oH oH oH pe 0 T — 2 T— |+q (x,y)eD,t>0 or ox ox oy oy H,(x,y,0)=0 (x,y)e D,t=0 Hy =0 (x,y)eT,,t>0 oH T—F# =0 (x,y)eT,,t>0 on r, The natural flow field model 1s: pH, _ 2 r Hy + & ro. +P+Ev (x,y)eD,t>0 ot Ox ox Oy Oy H, (x, y,0)=H, (x, y) (x,y)e D,t=0 H,|. =H, (x, y,t) (x,y)eT,,t>0

OH ro =q(x, 1.1) (x,y)eT,,t>0 on |p, Wherein, H ,is the first groundwater level calculated by the artificial flow field model, and H, is the second groundwater level calculated by the natural flow field model.

The groundwater flow numerical model is a relatively complicated non-homogeneous mathematical model, which is not convenient for superposition calculation. Therefore, in order to use the superposition principle to simplify the calculation of the groundwater resources management model, the groundwater flow numerical model can be decomposed into two parts, 7500829 the natural flow field model and the artificial flow field model. After the two models are superimposed, the groundwater flow numerical model can be obtained, and the equations of the decomposed artificial flow field model are homogeneous equations, which are easier to superimpose calculation, so the calculation process is simplified.

In some implementations of the first aspect, the groundwater in the study area is distributed in at least one aquifer, the production well is used to extract groundwater in one of the aquifers, and the groundwater flow numerical model is established based on the hydrological data of the aquifer being mined.

In some implementations of the first aspect, the optimization objective is characterized by

N a function max > 0,7, , the constraints is H > H,y » among them, N is the number of mining n=l wells, (J, is the amount of groundwater produced by the nth mining well in a unit time, 7; is the total mining time of the nth mining well and H, , is the lowest ecological water level.

In some implementations of the first aspect, according to the groundwater flow numerical model, iterative calculation is carried out with the maximum groundwater exploitation amount as the optimization objective and the groundwater level not lower than the minimum ecological water level as the constraint condition, and the target exploitation amount of each exploitation well in the study area is obtained, including: acquiring the groundwater level of each control point output by the groundwater flow numerical model; if the groundwater level of a control point is lower than the lowest ecological water level, the amount of groundwater extraction from mining wells located in the periphery of the control point is reduced, and increase the amount of groundwater extracted from mining wells located in the vicinity of the control point where the groundwater level is higher than the lowest ecological water level, and the increased amount of groundwater extracted shall not be less than the reduced amount of groundwater extracted, input new groundwater extraction into the groundwater flow numerical model, jump to the step of "obtaining the groundwater level of each control point output by the groundwater flow numerical model" step is performed iteratively, the iteration ends when the 7500829 groundwater level of all control points is not lower than the minimum ecological water level, determine the groundwater extraction volume corresponding to each mining well at the end of the iteration, and use the groundwater extraction volume as the target extraction volume for each mining well.

In the above process, through continuous optimization iterations, the water level state of the groundwater system and the amount of groundwater extraction can be adjusted according to the set optimization goals and constraints. In order to obtain the required target mining volume, it provides a basis for groundwater mining in the study area.

In some implementation manners of the first aspect, the method further includes: Select the groundwater observation data of the control point in multiple time periods, and calculate the difference between the maximum and the minimum groundwater depth in the groundwater observation data in the selected time period, and the average groundwater depth; performing a linear fitting on the ratio of the difference to the average evaporation intensity in each selected time period and the average buried depth of groundwater, and obtaining a fitting straight line; Determine the average groundwater depth corresponding to the fitting straight line when the ratio is zero, and determine the corresponding average groundwater depth as the lowest ecological water level 4, .

In some implementations of the first aspect, after obtaining the target production volume of each production well in the research area, the method further includes: determine the water source scheduling plan of the study area according to the target mining volume; the water source scheduling plan includes: if the target extraction volume meets the water demand in the study area, each extraction well is extracted according to the target extraction volume; If the target extraction volume cannot meet the water demand in the study area, the water source replacement method is used to supplement water for the mining wells in the area around the control point where the groundwater level is lower than the lowest ecological water level in the study area. 75006829 In some implementations of the first aspect, the groundwater flow numerical model is established on a pre-split three-dimensional grid, the three-dimensional grid divides the horizontal two-dimensional cross-section in the research area into a rectangular grid according to a set grid size, the three-dimensional grid divides the vertical aquifer profile in the study area according to the height of the top and bottom of the aquifer.

In the above solution, after the three-dimensional mesh is divided, the above groundwater flow numerical model is also discretized into a finite difference equation set, so that the model can be solved.

In the second aspect, an embodiment of the present application provides a groundwater management device, and the device includes: the model acquisition module is used to acquire the groundwater flow numerical model established by the hydrological data in the study area, the groundwater flow numerical model is used to describe the relationship between the groundwater level, the amount of groundwater extraction, and natural climate conditions in the study area; the optimization module is used to perform iterative calculations based on the groundwater flow numerical model with the maximum groundwater extraction as the optimization goal and the groundwater level not lower than the lowest ecological water level as the constraint condition, obtain the target mining volume of each mining well in the research area, where the lowest ecological water level represents the groundwater level corresponding to when the water level change due to evaporation is zero.

The above device effectively solves the management problem of groundwater resource exploitation, and can obtain the target groundwater exploitation plan of each mining well when the groundwater level of the control point meets the constraint conditions, it can provide a basis for the sustainable development and utilization of groundwater.

In some implementations of the second aspect, the device further includes: a model building module for obtaining hydrological data in the research area; and based on the hydrological data to establish a groundwater flow numerical model as shown below:

EU) Lr gpa (x,y)eD,t>0 or ox\ ox) oy\ oy H(x,y,0)=H(x,y) (x,y)e D,t=0 H| =H(x,y,1) (x,y)el',t>0 rl = q(x, 3,1) (x,y)eT,,t >0 On |r, Among them, D is the study area, H is the groundwater level of the control point, and (x, y) is the location of the mining well or control point, t is the time, E 1s the water storage parameter, T is the hydraulic conductivity, q is the groundwater extraction volume of the mining well, Ev is evaporation discharge, P is precipitation replenishment, H, (x, y) is the initial water level of the control point, and I’, is the first type boundary of the study area, l’, is the second type boundary of the study area, J (x, 3,1 ) is the water flow through the second type boundary, q, Fv, P H,(x,y), l',and l’, are determined by the hydrological data, and E and T are determined by the hydrological data to determine initial values and are determined after model parameter tuning.

In some implementation manners of the second aspect, the optimization module 1s specifically configured to: obtain the groundwater level of each control point output by the groundwater flow numerical model; if the groundwater level of a control point is lower than the lowest ecological water level, the amount of groundwater extraction from mining wells located in the periphery of the control point is reduced, and increase the amount of groundwater extraction from mining wells located in the vicinity of the control point where the groundwater level is higher than the lowest ecological water level, and increase the amount of groundwater extraction not lower than the amount of groundwater extraction reduced by the downward adjustment; inputting new groundwater extraction volume parameters into the groundwater flow numerical model; jump to the step of "obtain the groundwater level of each control point output by the groundwater flow numerical model" and iteratively execute until the groundwater level of all control points is not lower than the minimum ecological water level, and the iteration ends, determine the groundwater extraction volume corresponding to each mining well at the end of the iteration, and use the groundwater extraction volume as the target extraction volume of groundwater for each mining well. 7500829

BRIEF DESCRIPTION OF THE FIGURES In order to explain the technical solutions of the embodiments of the present application more clearly, the following will briefly introduce the drawings that need to be used in the embodiments of the present application, it should be understood that the following drawings only show certain embodiments of the application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative work, other related drawings can be obtained from these drawings.

Figure 1 is a flow chart of the groundwater management method provided by the first embodiment of the application; Figure 2 is a schematic diagram of the vertical section of the groundwater model; Figure 3 is a schematic diagram of the fitting process of multiple discrete points in the coordinate system when calculating the lowest ecological water level; Figure 4 is a flow chart of the optimization model during iterative calculations; Figure 5 is a schematic diagram of a groundwater management device provided by a second embodiment of the application.

DESCRIPTION OF THE INVENTION The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

The first embodiment Groundwater is the main source of water supply. In recent years, the excessive exploitation of groundwater has caused a series of environmental and geological problems. Moreover, due to the increase in water consumption in various regions and limited water resources, there have been more local overexploitations. At present, there is no effective means to manage the exploitation of groundwater in order to realize the rational development of groundwater resources. Therefore, this embodiment provides a groundwater management method, through mathematical simulation of the groundwater system, and an optimization model that makes the state of the groundwater system reach the optimal model according to the set target, to 7500829 determine the mining plan for groundwater, refer to Figure 1. The method includes the following steps: step 101: obtain a groundwater flow numerical model established from hydrological data in the study area.

The groundwater flow numerical model is established based on the hydrological data of the study area, and the models corresponding to different areas are different. Therefore, before the management of groundwater exploitation, the scope of the research area to be managed should be determined and get the hydrological data within the study area, among them, the hydrological data to be obtained mainly include meteorological and hydrological data, hydrogeological parameters and groundwater extraction data. For example, river water level elevations in water system maps, hydrogeological maps, and roof elevations and floor elevations of various aquifers in borehole data.

After obtaining the hydrological data of the study area, the scope, boundary conditions and initial conditions of the groundwater flow numerical model can be determined based on the hydrological data obtained. The scope of the model is consistent with the scope of the study area. The upper boundary of the model is the diving surface, through this boundary, groundwater is recharged by rainfall infiltration, and groundwater is discharged in the form of evaporation and runoff, the bottom boundary of the model is regarded as an impervious boundary, and the type of lateral boundary of the model is determined according to the specific hydrogeology at the boundary of the study area. There are underground rocks distributed between the upper boundary and the bottom boundary. The underground rocks contain groundwater in various states. Due to the different hydraulic properties of various rocks, various rock layers can be divided into aquifers, impermeable layers and impermeable aquifers, and aquifers can be divided into confined aquifers and phreatic aquifers. Figure 2 shows a schematic diagram of the vertical section of the groundwater model.

In reality, the number of aquifers contained in each region may be different. Some regions may contain two aquifers, while other regions may contain three or more aquifers. The specific number of aquifers does not affect the establishment of a groundwater flow numerical model. This embodiment takes two aquifers as an example.

In the process of establishing the numerical model of groundwater flow, there are mainly 7500829 two types of hydrogeological parameters used in the numerical model of groundwater flow. The first category is the hydrogeological parameters of aquifers, which mainly include the water supply, permeability coefficient, hydraulic conductivity of the phreatic aquifer, the permeability coefficient, hydraulic conductivity and elastic water release coefficient of the confined aquifer, the other type is used to calculate the parameters and empirical coefficients of groundwater replenishment, such as rainfall infiltration coefficient, irrigation infiltration coefficient and so on.

It should be noted that for mining wells, some wells are dug shallowly and only mine water from phreatic aquifers, while some wells are dug deep and mine water from confined aquifers. However, the same mining well can only mine to the water level of one aquifer. If the mining well mines the groundwater of phreatic aquifer, generally, the groundwater in confined aquifer cannot be exploited, and vice versa. Without considering the overflow, the water level gauges of the two aquifers can be regarded as independent. Therefore, the numerical model of groundwater flow can be established based on the hydrological data of the aquifer being mined, and the parameters in the model are determined by the hydrological data.

The numerical model of groundwater flow is used to describe the relationship between groundwater level and groundwater exploitation and natural climate conditions such as precipitation and evaporation, according to the local water resources exploitation and climate conditions, the groundwater level at the control points can be simulated, and the model can be calculated by the following formula: PBL [rH en (x,y)eD,t>0 (1) H(x,y,0)=H,(x,y) (x,y)eD,1=0 (2) Hl. =H(x,y,t) (x,y)el',t>0 (3) rl =q(x,y,t) (x,y)eTl,,i>0 (4) on |, In the above formula, D is the study area, H is the groundwater level of the control point, (x, J ) is the location of the mining well or control point, t is the time, E is the water storage parameter, T is the hydraulic conductivity, and q is the groundwater extraction volume of the mining well, Ev is evaporation discharge, P is precipitation replenishment, Hy (x. J ) is the SRE initial water level of the control point, [, is the head boundary of the study area, I is the flow boundary of the study area, n represents the projection of the water flow entering the flow boundary to the direction perpendicular to the boundary, ¢ (x, 3,1 ) is the water flow through the flow boundary, q, Fv, PH, (x,y), land I, are determined by hydrological data, and E and T are determined by hydrological data to determine initial values and are determined after model parameter tuning.

It should be noted that the above-mentioned mining well is a well with groundwater exploitation, which is a well for extracting groundwater in actual production and life or a point generalized by well groups, while the control point is an observation well, which is used for measuring and monitoring the groundwater level and does not generally have a large exploitation amount. In some possible embodiments, the production well can also be used as an observation before the groundwater is mined, but generally do not use mining wells during or after mining as observation wells or control points After obtaining the hydrological data of the study area, an initial groundwater flow numerical model can be established based on the aquifers collected by each mining well. Exemplarily, a certain historical time is used as the initial time, and the water level of the phreatic aquifer and confined aquifer actually observed at that time is used as the initial water level of the control point, use interpolation method (such as Kriging difference method, etc.) to obtain the initial water level H, (x, y) of the aquifer, and determine the initial value of the water storage parameter E and the hydraulic conductivity T through hydrogeological data or pumping test, establish a numerical model of groundwater flow. In this initial groundwater flow numerical model, the initial values of the water storage parameter E and the hydraulic conductivity T can be determined in the following way: When the groundwater level is greater than or equal to TOP, E=S, T=KM, S is the elastic water storage coefficient, K 1s the permeability coefficient of the aquifer, M 1s the thickness of the aquifer, and TOP is the roof elevation of the aquifer; when the groundwater level is less than TOP, E=yu, u is the water supply degree of the aquifer, T=K (H-Bol), K is the permeability coefficient of the aquifer, and Bol is the floor elevation of the aquifer. The aquifer referred to above is any aquifer described. The water storage parameters E and the hydraulic conductivity T in the groundwater flow numerical models corresponding to the phreatic aquifer and the confined aquifer are all determined by the above methods.

After the initial parameters in the groundwater flow numerical model are determined by LU500829 the above method, the model is trained using historical observation data. Compare the predicted water level of the groundwater flow numerical model at the historical moment with the actual measured water level at the historical moment, and continuously adjust the parameter values of the water storage parameter E and the hydraulic conductivity T in the model, until the difference between the groundwater level H obtained by the model calculation and the actually observed groundwater level meets the accuracy requirements, the adjustment of the parameters shall be stopped. Therefore, the values of the water storage parameter E and the water conductivity T are finally adjusted from the initial value to the required target value. The E and T at this time are substituted into the model for calculation to form a groundwater flow numerical model that is finally used to simulate the groundwater system. Furthermore, the inventor found that the water storage parameter E changes very little in practice, and in an optional scheme, only the water conductivity T can be adjusted.

To obtain the groundwater level of the control point, it is necessary to solve the groundwater flow numerical model, and the groundwater flow numerical model includes continuous partial differential equations, so it can be calculated by discretizing the above equations. In one embodiment, the above-mentioned groundwater flow numerical model is established on a pre-split three-dimensional grid, and the three-dimensional grid is obtained after subdividing the three-dimensional groundwater model. The three-dimensional groundwater model is a conceptual model that describes the groundwater flow in the study area. The method of establishment is as follows: after determining the study area for groundwater management, according to the drilling geological data of the study area, determine the ground elevation, the top and bottom elevations of the phreatic aquifer and confined aquifer of known fixed points, use Kriging interpolation and other methods to calculate the surface elevation, phreatic aquifers and confined aquifers in the study area, and according to the well position information of each mining well, a three-dimensional groundwater model is established.

Choose an appropriate grid size and perform 3D meshing on the established 3D groundwater model. Among them, the horizontal two-dimensional plane is divided into rectangular grids according to the selected grid size, and the vertical aquifer section is divided according to the elevation of the top and bottom of the aquifer to form a three-dimensional grid. For example, spatially divide the horizontal two-dimensional plane of the entire three- dimensional groundwater model into a regular matrix grid of 50 rows and 30 columns, and each layer adopts a subdivision format of 800m*800m, when splitting, the number of rows and columns selected is not strictly required, but the smaller the grid, the more accurate the final calculation result will be, and the slower the calculation speed will be. After the three- LU500829 dimensional mesh is divided, the above-mentioned groundwater flow numerical model is also discretized into a finite difference equation set, so that the model can be solved.

Step 102: According to the groundwater flow numerical model, perform iterative calculation with the maximum groundwater extraction volume as the optimization objective and the groundwater level not lower than the minimum ecological water level as the constraint condition to obtain the target extraction volume of each mining well in the research area.

According to the accurate simulation of the groundwater system based on the groundwater flow numerical model, the groundwater level of each control point at different times can be determined, and the groundwater level can be used in the optimization model for optimization calculation. The optimization model takes the maximum amount of groundwater exploitation as the optimization objective, and the groundwater level is not lower than the minimum ecological water level as the constraint condition, so that the artificial groundwater exploitation can not only achieve the maximum amount of exploitation, but also maintain the good development and growth of vegetation and realize the rational and sustainable development of

N water resources. The optimization objective can be characterized by function max > 0,7, , n=l constraints can be expressed by Formula H =H, - In which n is the number of mining wells, O, is the groundwater exploitation amount of the nth mining well in unit time, 7, is the total mining time of the nth mining well, the lowest ecological water level H,, represents the lowest groundwater level that can maintain the well-developed growth of typical vegetation. O, is obtained after discrete groundwater extraction q in the model.

The lowest ecological water level in the optimization model is obtained based on the observation data of the control points. First, select the groundwater observation data of the control points in multiple time periods, calculate the difference A/ between the maximum and minimum groundwater depths in the groundwater observation data during the selected time period, and the average groundwater depth h- AR = Pax —h, - 7 _ ho + in 2 2 h . . . . . h..

max is the maximum value of groundwater depth in the selected time period, and min is the minimum value of groundwater depth in the selected time period. In order to ensure the LU500829 generality of the data, the number of selected time periods can be as large as possible.

Then, according to the difference Ah corresponding to each time period, calculate the ratio X of the difference to the average evaporation intensity & . Take the average groundwater depth h as the abscissa, and the ratio X as the ordinate, draw multiple discrete points formed by multiple time periods in a coordinate system, and perform linear fitting on the multiple discrete points in the coordinate system to obtain a fitting straight line, the fitting straight line passes through the center of the point group, and its intersection with the abscissa indicates the average groundwater depth when the water level change due to evaporation is zero. The lowest ecological water level H,, is the average groundwater depth corresponding to the intersection of the fitted straight line and the abscissa (that is, the point on the straight line where the ratio X is zero). It should be noted that the selected time period will have a certain impact on the final fitting straight line, which will affect the final lowest ecological water level. Figure 3 shows the fitting process of multiple discrete points in the coordinate system.

After determining the optimization objectives and constraints of the optimization model, the specific calculation of the optimization model is a mathematical optimization problem. Iterative calculation is used to obtain the target solution that meets the set conditions. The variables that exist are divided into state variables and decision variables, the state variable is the groundwater level, which is obtained through the partial differential equation in the groundwater flow numerical model, and the decision variables are the production volume, number, and location of the well. Referring to Figure 4, the iterative calculation process includes the following steps: Step 201: obtain the groundwater level of each control point output by the groundwater flow numerical model.

Step 202: adjust the groundwater extraction volume of each mining well according to the groundwater level of each control point.

If the groundwater level of a control point is lower than the lowest ecological water level, the amount of groundwater extraction from mining wells located in the vicinity of the control point will be reduced. At the same time, for the control point where the groundwater level is higher than the lowest ecological water level, increase the amount of groundwater extracted from the mining wells around the control point. When adjusting the extraction volume, it is LU500829 necessary to ensure that the increased amount of groundwater extraction is not lower than the reduced amount of groundwater extraction. The model is continuously optimized in the direction of greater mining volume to find the maximum value of mining volume.

Step 203: input the new groundwater extraction amount into the groundwater flow numerical model.

Substitute the adjusted extraction volume into the groundwater flow numerical model for calculation, and perform steps 201-203 again. The iterative process ends when the groundwater level of all control points is higher than or equal to the lowest ecological water level, the groundwater production volume corresponding to each mining well at the end of the iteration is taken as the target production volume of each mining well, the target mining volume at this time is the maximum mining volume that meets the water level constraint. So as to maximize the amount of groundwater extraction in the study area, and to ensure that the groundwater level will not be lower than the minimum ecological water level.

Through the above scheme, the groundwater flow numerical model established by the hydrological data of the study area is used to accurately simulate the water level changes of the groundwater system at different times and different mining wells and different production volumes. Provide a basis for the optimal management of the groundwater system, so as to perform iterative calculations through the set optimization goals and constraint conditions, make the water level state of the groundwater system and the amount of groundwater extracted can be adjusted according to the set iterative conditions, so as to obtain the required target exploitation amount and provide a basis for groundwater exploitation in the study area, further, the above optimization objective is to maximize the amount of groundwater exploitation. However, maximizing the exploitation of underground water in a certain area often means that the area can obtain the greatest economic benefits. Therefore, the above scheme can also maximize the economic benefits in the study area.

It should be noted that the above numerical model of groundwater flow is a more complex mathematical model. It is composed of non-homogeneous partial differential equations and their definite solution conditions. It does not satisfy the superposition principle and cannot simply use the linear system iterative method for groundwater resources management research. Therefore, in order to use the superposition principle to simplify the calculation of the groundwater resources management model, the groundwater flow numerical model can be decomposed into two parts, the natural flow field model and the artificial flow field model. After the two models are superimposed, the groundwater flow numerical model can be obtained.

In the following formula of this embodiment, the subscript n represents the symbol of the LU500829 natural flow field, and the subscript p represents the symbol of the artificial flow field. Other symbols themselves have the same meaning as the groundwater flow numerical model. The decomposed natural flow field model and artificial flow field model are as follows: po _ © r Hy a r Hy +P+Ev (x,y)e D,t>0 ot Ox ox Oy Oy H, (x, y,0)=H, (x, y) (x,y)e D,t=0 H,|. =H, (x, y,t) (x,y)eT,,t>0

OH ro =q(x, 1.1) (x,y)eT,,t>0 on |p, oH oH oH pe 0 T — 2 T— |+q (x,y)eD,t>0 or ox ox oy oy H,(x,y,0)=0 (x,y)e D,t=0 Hy =0 (x,y)eT,,t>0 oH T—F# =0 (x,y)eT,,t>0 on r, In the above formula, His the groundwater level calculated by the natural flow field model, and H , is the groundwater level calculated by the artificial flow field model, regardless of the factors of artificial groundwater extraction, the natural water level H, of each control point at different times can be obtained according to the natural flow field model. Combined with the water level À , obtained under the action of manual pumping, after the groundwater level obtained by the two models is superimposed, the groundwater level H in the groundwater flow numerical model can be obtained, the equations of the decomposed artificial flow field model belong to homogeneous equations, which are easier to superimpose calculation, which simplifies the calculation process of the model and increases iteration rate.

The groundwater level H ,is the water level change caused by artificial pumping and mining. In the process of solving the above artificial flow field model, the response matrix method can be used, the response matrix is obtained by superimposing the impulse response of each control point, that is, the water level change in the artificial flow field model is calculated

N by formula f(x,y) = Dax, VOI, . Among them, n=1,2,3,..,N, N is the number of mining n=l wells, Œ, (x > y) is the groundwater level drop of the control point caused by the nth mining 7500829 well under the unit time and unit mining volume, that is, the impulse response corresponding to the control point, O, and T have the same meaning as in the function of the optimization objective.

If the above two models are used to calculate the groundwater level H, then in the process of iterative optimization, it is also possible to simplify the calculation amount in the iterative process only by calculating the groundwater level of the artificial flow field model. For example, after the first iterative calculation, adjust the groundwater extraction volume of each mining well, and substitute the updated groundwater extraction volume q into the artificial flow field model for calculation. Obtain the groundwater level # ,, and then superimpose it with the natural water level H, obtained by the natural flow field model to obtain the groundwater level H at each control point in the new iteration. In the entire iterative process, the natural water level H, obtained by the natural flow field model is not affected by changes in the extraction volume. Therefore, there is no need to calculate the natural water level H, after the initial calculation. From each iteration, only the artificial flow field model needs to be calculated separately, and then it can be superimposed with the natural water level H,, which greatly reduces the iteration calculation amount.

After obtaining the target production volume of each mining well through step 102, the local water source scheduling plan in the study area can be determined according to the target production volume. If the target mining volume can meet the water demand in the study area, then the mining plan at this time is considered to be the optimal mining plan. The mining plan of key mining wells can be formulated according to the target mining volume. If the target mining volume cannot meet the water demand in the study area, then, water source replacement, such as surface water or external water transfer, should be used to replenish the mining wells near the control point where the groundwater level is lower than the lowest ecological water level.

In summary, the groundwater management method provided in this embodiment uses the inherent hydrogeological characteristics of the groundwater system to establish a groundwater flow numerical model. It is used to simulate and describe the groundwater level of each control point in the study area, and use an optimized model based on the groundwater level obtained by the simulation, by optimizing and regulating the artificial extraction volume of the groundwater system, the groundwater system finally reaches a balanced state according to the LU500829 set optimization goals and constraints and get the target mining volume in this equilibrium state.

The mining of each mining well through the optimized target mining volume is a reasonable mining of groundwater resources. After mining, the groundwater level of each control point is not lower than the minimum ecological water level. So as to solve the problem of excessive exploitation of groundwater resources and realize the sustainable development and utilization of groundwater resources. Furthermore, it also enables limited groundwater resources to maximize economic benefits.

The second embodiment This embodiment provides a groundwater management device. Referring to FIG. 5, the device includes: the model acquisition module 301 is used to acquire the groundwater flow numerical model established by the hydrological data in the research area, the groundwater flow numerical model is used to describe the relationship between the groundwater level in the study area, the amount of groundwater extracted, and the natural climate conditions.

The optimization module 302 is used to perform iterative calculations based on the groundwater flow numerical model with the maximum groundwater extraction as the optimization objective and the groundwater level not lower than the minimum ecological water level as the constraint condition, obtain the target mining volume of each mining well in the research area, where the lowest ecological water level represents the groundwater level corresponding to when the water level change due to evaporation is zero.

Optionally, the device further includes a model building module for acquiring hydrological data in the study area, and establishing a groundwater flow numerical model as shown below based on the hydrological data: POELE gpa (x,y)eD,t>0 or ox\ ox) oy\ oy H(x,y,0)=H(x,y) (x,y)e D,t=0 H| =H(x,y,1) (x,y)el',t>0 rl = q(x, 3,1) (x,y)eT,,t >0 On |r, Among them, D is the study area, H is the groundwater level of the control point, (x, y) is the location of the mining well or control point, tis the time, E 1s the water storage parameter, T is the hydraulic conductivity, and q is the groundwater extraction volume of the mining well,

Ev is evaporation discharge, P is precipitation replenishment, #, (x, y) is the initial water L 7900829 level of the control point, I’, is the first type of boundary of the study area, 1°, is the second type of boundary of the study area, q(x,y,t ) is the water flow through the second type boundary, q, Ev, PH,(x,y), ljand l', are determined by the hydrological data, and E and T are determined by the hydrological data to determine initial values and are determined after model parameter tuning.

Optionally, the optimization module 302 is specifically configured to: obtain the groundwater level of each control point output by the groundwater flow numerical model; if the groundwater level of a control point is lower than the lowest ecological water level, the amount of groundwater extraction from mining wells located in the periphery of the control point is reduced, and increase the amount of groundwater extracted from mining wells located in the vicinity of the control point where the groundwater level is higher than the lowest ecological water level, the groundwater extraction volume increased by the upward adjustment shall not be lower than the reduction volume by the downward adjustment; inputting new groundwater extraction volume parameters into the groundwater flow numerical model; jump to the step of "obtaining the groundwater level of each control point output by the groundwater flow numerical model" step is performed iteratively, the iteration ends when the groundwater level of all control points is not lower than the minimum ecological water level, determine the groundwater extraction volume corresponding to each mining well at the end of the iteration, and use the groundwater extraction volume as the target extraction volume of groundwater for each mining well.

Optionally, the device further includes a lower limit calculation module for selecting groundwater observation data of the control point in multiple time periods, calculate the difference between the maximum value and the minimum value of the groundwater depth in the groundwater observation data in the selected time period, and the average groundwater depth; performing a linear fitting on the ratio of the difference to the average evaporation intensity in each selected time period and the average buried depth of groundwater, and obtaining a fitting straight line; determine the average groundwater depth corresponding to the fitting straight line when the ratio is zero, and determine the corresponding average groundwater depth as the lowest ecological water level fH, - It should be understood that the groundwater management device provided in this embodiment and the groundwater management method provided in the first embodiment are based on the same inventive concept. As for the device embodiment, since it is basically similar LU500829 to the method embodiment, the description is relatively simple. For related parts, please refer to the part of the description of the method embodiment, which will not be described in detail here.

In the several embodiments provided in this application, it should be understood that the disclosed device and method may also be implemented in other ways. The above-described device embodiments are only schematic, for example, the flowcharts and block diagrams in the drawings show the architecture, functions and operations of possible implementations of devices, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, program segment or part of code that contains one or more executable instructions for implementing specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the block may also occur in a different order from the order marked in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, or they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and/or flowchart, and combinations of blocks in the block diagram and/or flowchart, may be implemented by dedicated hardware-based systems that perform specified functions or actions, or may be implemented by combinations of dedicated hardware and computer instructions.

In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist alone, or two or more modules may be integrated to form an independent part.

If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence or the part that contributes to the existing technology or the part of the technical solution. The computer software product is stored in a storage medium and includes a number of instructions to enable a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read only memory (ROM), random access memory (RAM), magnetic disk or optical disk and other media that can store program code.

The above descriptions are only examples of the application, and are not used to limit the protection scope of the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made LV500829 within the spirit and principle of this application shall be included in the protection scope of this application.

It should be noted that in this article, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, as a result, a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to the process, method, article, or device. If there are no more restrictions, the element defined by the sentence "including a..." does not exclude the existence of other identical elements in the process, method, article, or equipment that includes the element.

Claims

CLAIMS LU500829

1. À groundwater management method, characterized in that it comprises: acquiring a groundwater flow numerical model established by hydrological data in the research area, where the groundwater flow numerical model is used to describe the relationship between the groundwater level in the research area and the amount of groundwater extraction and natural climate conditions: according to the numerical model of groundwater flow, an iterative calculation with maximum groundwater extraction as the optimization goal and groundwater level not lower than the lowest ecological water level as the constraint condition is carried out, obtaining the target mining volume of each mining well in the research area, where the lowest ecological water level refers to the corresponding groundwater level when the water level fluctuation caused by evaporation becomes zero.

2. The method according to claim 1, characterized in that, before obtaining a groundwater flow numerical model established from hydrological data in the study area, the method further comprises: obtaining hydrological data in the study area; according to the hydrological data, the groundwater flow numerical model as shown below is established: BR ÉTÉ 2 r CH +q+Ev+P (x,y)eD,t>0 or ox\ ox) oy\ oy H(x,y,0)=H(x,y) (x,y)e D,t=0 H| =H(x,y,1) (x,y)el',t>0

H rf = q(x, 3.1) (x,y)el,,t>0 on |r, among them, D is the study area, H is the groundwater level of the control point, (x, y) is the location of the mining well or control point, tis the time, E 1s the water storage parameter, and T is the hydraulic conductivity, q 1s the groundwater extraction volume of the mining well, Ev is the evaporation discharge, P is the precipitation replenishment, H, (x, y) is the initial water level of the control point, I’, is the first type boundary of the study area, I’, is the second type boundary of the study area, ¢ (x, 3,1 ) is the water flow through the second type boundary, q, £V, P, H,(x,y), land I, are determined by the hydrological data, the initial values of E and T are determined by the hydrological data and determined after model parameter tuning. LU500829

3. The method of claim 2, wherein the groundwater flow numerical model includes an artificial flow field model and a natural flow field model, the groundwater level output by the groundwater flow numerical model is obtained by superposing the first groundwater level calculated by the artificial flow field model and the second groundwater level calculated by the natural flow field model; the artificial flow field model is: oH oH oH pe 0 T — 2 T— |+q (x,y)eD,t>0 or ox ox oy oy H,(x,y,0)=0 (x,y)e D,t=0 Hy =0 (x,y)eT,,t>0 oH T—F# =0 (x,y)eT,,t>0 on r, the natural flow field model is: pu _ r Hy a r Hy +P+Ev (x,y)eD,t>0 ot Ox ox Oy Oy H,(x,y,0)= H,, (x,y) (x,y)e D,t =0 H,|. =H, (x,y,1) (x,y)eT,,t>0 ro =q(x,y.t) (x, y) eT,,t >0 On |p, wherein, 1 is the first groundwater level calculated by the artificial flow field model, and 2 1s the second groundwater level calculated by the natural flow field model.

4. The method of claim 2, wherein the groundwater in the study area is distributed in at least one aquifer, and the mining well is used to extract the groundwater in one of the aquifers, the groundwater flow numerical model is established based on the hydrological data of the aquifer being mined.

5. The method of claim 2, wherein the optimization objective is characterized by function

N max > 0,7, , and the constraint condition is A > H,,» among them, N is the number of n=l mining wells, J, is the amount of groundwater produced by the nth mining well in a unit time, 7, is the total mining time of the nth mining well, and H,, is the lowest ecological water level.

6. The method according to claim 3, characterized in that, according to the groundwater flow numerical model, carry out iterative calculations with the maximum groundwater LU500829 extraction volume as the optimization goal and the groundwater level not lower than the lowest ecological water level as the constraint condition to obtain the target extraction volume of each mining well in the study area, including: acquiring the groundwater level of each control point output by the groundwater flow numerical model; if the groundwater level of a control point is lower than the lowest ecological water level, the amount of groundwater extraction from mining wells located in the periphery of the control point is decreased, and increase the amount of groundwater extracted from mining wells located in the vicinity of the control point where the groundwater level is higher than the lowest ecological water level, the increased amount of groundwater extraction is not less than the decreased amount of groundwater extraction; inputting new groundwater extraction into the groundwater flow numerical model; jump to the step of "obtain the groundwater level of each control point output by the groundwater flow numerical model" and execute iteratively, the iteration ends when the groundwater level of all control points is not lower than the minimum ecological water level, determine the groundwater extraction volume corresponding to each mining well at the end of the iteration, and use the groundwater extraction volume as the target extraction volume for each mining well.

7. The method according to claim 5, wherein the method further comprises: select the groundwater observation data of the control point in multiple time periods, and calculate the difference between the maximum and the minimum groundwater depth in the groundwater observation data in the selected time period, and the average groundwater depth; performing a linear fitting on the ratio of the difference to the average evaporation intensity in each selected time period and the average buried depth of groundwater, and obtaining a fitting straight line; determine the average groundwater depth corresponding to the fitting straight line when the ratio is zero, and determine the corresponding average groundwater depth as the lowest ecological water level H, -

8. The method according to claim 1, wherein after obtaining the target production volume of each production well in the research area, the method further comprises: determine the water source scheduling plan of the study area according to the target mining volume;

the water source scheduling plan includes: LU500829 if the target extraction volume meets the water demand in the study area, each extraction well is extracted according to the target extraction volume; if the target extraction volume cannot meet the water demand in the study area, the water source replacement method is used to supplement water for the mining wells in the area around the control point where the groundwater level is lower than the lowest ecological water level in the study area.

9. The method according to claim 2, wherein the groundwater flow numerical model is established on a pre-split three-dimensional grid, the three-dimensional grid divides the horizontal two-dimensional cross-section in the research area into a rectangular grid according to a set grid size, and the three-dimensional grid divides the vertical aquifer profile in the research area according to the aquifer top plate elevation and the aquifer bottom plate elevation.

10. A groundwater management device, characterized in that the device includes: the model acquisition module is used to acquire the groundwater flow numerical model established by the hydrological data in the study area, the groundwater flow numerical model is used to describe the relationship between the groundwater level, the amount of groundwater extraction, and natural climate conditions in the study area; the optimization module is used to perform iterative calculations based on the groundwater flow numerical model with the maximum groundwater extraction as the optimization goal and the groundwater level not lower than the lowest ecological water level as the constraint condition, obtain the target exploitation amount of each exploitation well in the study area, wherein, the lowest ecological water level represents the corresponding groundwater level when the water level change caused by evaporation is zero.