Method for identifying dominant mechanism of solute transformation of gated river

Abstract

The invention discloses a gate-controlled river solute conversion dominant mechanism identification method. The method comprises the following steps: acquiring basic data of a target gate-controlled river reach; according to the basic data, constructing a solute multiphase transformation model covering the transformation process of the water body, the suspended solids and the bottom mud; different sluice scheduling scenes and reference scenes are set, and the space-time concentration change process of different phase state solutes in each scene is simulated; calculating a sluice scheduling total contribution rate and a contribution ratio of each reaction mechanism based on the solute multiphase conversion model; and identifying a solute conversion dominant reaction mechanism under different scheduling scenes according to the contribution ratio. The method quantitatively analyzes the influence of sluice scheduling on solute conversion, provides theoretical guidance for scientifically formulating a scheduling scheme and improving river environment quality, and is suitable for the technical field of water environment assessment and management.

Description

Technical Field

[0001] The present invention belongs to the technical field of water environment assessment and management, and in particular relates to a method for identifying a dominant mechanism of solute transformation in a gate-controlled river. Background Art

[0002] In river systems, water quality transformation is a complex process involving multiple physical, chemical, and biological processes. Particularly in river sections with sluice gates, their operation significantly alters the hydrodynamic conditions of the river channel, such as flow velocity, water level, and sediment movement. This, in turn, significantly impacts the migration and transformation of solutes in the river, as well as their distribution among the water column, suspended matter, and sediment. Traditional river simulation and water quality assessment methods often struggle to comprehensively and quantitatively capture these complex multiphase transformation processes, nor do they clearly define the extent to which sluice gate operation influences specific reaction mechanisms (such as adsorption, sedimentation, and mineralization).

[0003] Existing research has largely focused on the macro-impacts of dam construction on hydrological regimes and the water environment. However, there is a lack of systematic, quantitative analysis of how specific dam operation methods drive the various reaction mechanisms involved in multiphase transformations in water quality, and which mechanisms play a dominant role under different operation scenarios. This makes it difficult to specifically utilize or inhibit specific reaction processes when developing combined dam and sluice operation plans to improve water quality, limiting the role of dams and sluices in water environment management.

[0004] Therefore, there is an urgent need for a method that can deeply analyze and quantitatively identify the dominant reaction mechanism affecting river solute transformation under different sluice operation scenarios, so as to provide technical support for refined and scientific sluice operation practices. Summary of the Invention

[0005] The purpose of this invention is to provide a method for identifying the dominant mechanism of solute transformation in gate-controlled rivers. By constructing a multiphase transformation model and contribution rate analysis, the impact of sluice scheduling is quantitatively evaluated, the dominant reaction mechanism is identified, and a scientific basis is provided for optimizing scheduling plans and improving water quality.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for identifying a dominant mechanism of solute transformation in a gate-controlled river, the method comprising:

[0008] Obtain basic data of the target gate-controlled river section,

[0009] Constructing a solute multiphase transformation model covering the transformation processes of water, suspended matter and sediment based on the basic data;

[0010] Set different sluice operation scenarios and reference scenarios, and simulate the temporal and spatial concentration changes of different phase solutes under each scenario;

[0011] Calculate the total contribution rate of sluice operation and the contribution ratio of each reaction mechanism based on the solute multiphase transformation model;

[0012] The dominant reaction mechanism of solute transformation under different scheduling scenarios is identified based on the contribution ratio.

[0013] Furthermore, the solute multiphase conversion model includes but is not limited to simulating one or more of the following reaction mechanisms: migration and diffusion, adsorption and desorption, sedimentation and resuspension, mineralization, nitrification and denitrification.

[0014] Furthermore, the total contribution rate of sluice operation and the contribution ratio of each reaction mechanism are calculated based on the solute multiphase conversion model as follows:

[0015] Calculating the total contribution rate of sluice operation of each sluice operation scenario relative to the reference scenario based on the solute multiphase conversion model;

[0016] According to the simulation process or simulation results of the solute multiphase conversion model, the contribution of each reaction mechanism affecting the concentration change of different phase solutes is separately calculated, and the contribution ratio of each reaction mechanism in the total contribution rate is calculated.

[0017] Furthermore, the calculation formula for the total contribution rate of sluice scheduling is:

[0018]

[0019] in, is the average concentration value of a phase solute under a certain sluice operation scenario; is the average concentration value of the solute in the phase without a gate or in the reference scenario.

[0020] Furthermore, the separate calculation of the contribution of each reaction mechanism affecting the concentration change of different phase solutes includes: separating the concentration change of a specific phase solute caused by each reaction mechanism within a unit time step or a simulation cycle from the calculation process of the solute multiphase conversion model.

[0021] Furthermore, the formula for calculating the contribution ratio of each reaction mechanism to the total contribution ratio is:

[0022]

[0023] Where, ΔC i is the total concentration change of the specific phase solute caused by the i-th reaction mechanism during the simulation period; Σ|ΔC j | is the sum of the absolute values ​​of the total concentration change caused by all reaction mechanisms j affecting the specific phase solute.

[0024] Furthermore, the dominant reaction mechanism of solute conversion under different scheduling scenarios is identified based on the contribution ratio as follows:

[0025] A grading standard for the contribution ratio is set, and the dominance of the reaction mechanism is determined based on the grading standard.

[0026] Furthermore, the sluice gate scheduling scenario includes different gate opening modes and / or different gate opening degrees.

[0027] Furthermore, the basic data includes river geometry data, hydrological data, meteorological data, water quality monitoring data and sediment characteristic data.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] This invention provides a method for identifying the dominant mechanisms of solute transformation in gate-controlled rivers. By constructing a multiphase solute transformation model that considers the coupled processes of water, suspended matter, sediment, and their interfaces, and introducing the concepts of the total contribution rate of sluice operation and the contribution ratio of each reaction mechanism, this method quantitatively analyzes the impact of different sluice operation scenarios on river solute transformation and scientifically identifies the key reaction mechanisms that dominate under specific operation modes. This method overcomes the limitations of traditional methods in quantitatively assessing the impact of sluice operation and identifying the dominance of specific mechanisms. It provides a powerful technical tool for water quality management and operation optimization in gate-controlled rivers, and facilitates more effective utilization of sluice and dam projects to improve river environmental quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings illustrate various embodiments generally by way of example and not limitation, and together with the description and claims, serve to explain embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive of the embodiments of the present apparatus or method.

[0031] Figure 1 A schematic flow chart of the method of the present invention is shown. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] The purpose of this invention is to provide a method for identifying the dominant mechanism of solute transformation in gate-controlled rivers, which can quantitatively evaluate the impact of sluice operation on the multiphase transformation of river solutes and identify the dominant reaction mechanism under different operation scenarios, thereby providing a scientific basis for optimizing sluice operation to improve water quality.

[0034] like Figure 1As shown, the present invention provides a method for identifying the dominant mechanism of solute transformation in a gate-controlled river, comprising:

[0035] Step 100: Obtain basic data of the target gate-controlled river section.

[0036] The basic data used to construct and run the solute multiphase transformation model include, but are not limited to, river reach geometry data (e.g., river cross-section, topography), hydrological data (e.g., upstream inflow, downstream water level boundaries), meteorological data (e.g., precipitation, evaporation, and temperature), water quality monitoring data (covering different solutes in the dissolved, suspended, and sediment phases, such as nitrogen, phosphorus, and organic matter), and sediment physicochemical properties. This data can be obtained through field surveys, remote sensing, historical data collection, and monitoring.

[0037] Step 200: Constructing a solute multiphase transformation model for the target gate-controlled river section based on the basic data.

[0038] The solute multiphase transformation model is a mathematical model that simulates the migration, transformation, and exchange of solutes between the water, suspended matter, and sediment phases in a river system. The model should be able to describe key reaction mechanisms, such as:

[0039] a) Physical processes: convection and diffusion of solutes in water; sedimentation and resuspension of suspended matter; exchange between water and sediment.

[0040] b) Biochemical processes: mineralization, nitrification, and denitrification of organic matter; consumption and replenishment of dissolved oxygen; adsorption and desorption of solutes on the surface of water bodies, suspended matter, and bottom mud; growth and death and decomposition of algae (if a biological phase is involved).

[0041] The construction of the model requires the selection of appropriate modules and parameterization schemes based on the characteristics of the actual river section, and the calibration and verification of the model to ensure that it can accurately simulate the hydrodynamic and water quality processes of the study river section.

[0042] Step 300: setting different sluice operation scenarios for the sluice-controlled river section, and setting a no-sluice or reference scenario.

[0043] The sluice gate operation scenarios are intended to reflect the impact of different gate operation modes on the hydrodynamic conditions of the river section. This can include changing the gate opening method (such as opening some or all gates) and / or changing the gate opening (such as closing, small opening, large opening). A series of representative operation scenarios should be set to cover actual or potential operation modes. At the same time, a no-sluice or reference scenario needs to be set as a control benchmark, such as no sluice gates at all or fully open sluice gates (simulating natural river conditions) to evaluate the changes caused by sluice gate operation.

[0044] Step 400: Based on the solute multiphase conversion model, simulate the different sluice operation scenarios and the no-sluice or reference scenario to obtain the spatiotemporal concentration variation process of different phase solutes under each scenario.

[0045] The scheduling scenarios set in step 300 are input into the model as boundary conditions or internal control parameters. Simulation calculations are performed using the solute multiphase transformation model constructed in step 200. The simulation should cover a sufficiently long time period to capture the dynamic process of solute transformation. The simulation output is the concentration of each target solute in the dissolved, suspended, and sediment phases of the water at different time points and spatial locations (e.g., sections above and below the gate).

[0046] Step 500: Based on the simulation results, calculate the total contribution rate of the sluice operation of each sluice operation scenario relative to the no-sluice or reference scenario.

[0047] The total contribution rate of sluice operation is used to quantitatively evaluate the degree to which a specific sluice operation mode changes the overall solute conversion state of the river section. The average concentration of a specific phase solute (for example, the concentration of dissolved nitrogen in the water body) under a certain sluice operation scenario can be calculated. and compared with the average concentration under no-gate or reference scenarios The calculation formula for the total contribution rate (γ) of sluice gate scheduling is:

[0048]

[0049] A higher absolute value of the contribution rate indicates that the scheduling scenario has a greater impact on the water quality transformation state.

[0050] Step 600: Based on the simulation process or simulation results of the solute multiphase conversion model, separately calculate the contribution of each reaction mechanism that affects the concentration change of different phase solutes, and calculate the contribution ratio of each reaction mechanism in the total contribution rate of the sluice operation.

[0051] When calculating the concentration change of each phase solute, the solute multiphase transformation model usually calculates the concentration change rate or change amount caused by different reaction mechanisms separately. For example, the concentration change of dissolved ammonia nitrogen (DNH3) in water may be affected by mechanisms such as mineralization (increase DNH3), nitrification (reduce DNH3), denitrification (increase DNH3 if nitrate is reduced) and algae ingestion (reduce DNH3). By recording during the calculation process of the model or analyzing from the output results the contribution of each mechanism to the change in specific solute concentration per unit time step or the entire simulation period (ΔC i ), the intensity of each mechanism can be quantitatively analyzed.

[0052] On this basis, the contribution ratio of each reaction mechanism is calculated The contribution ratio reflects the relative importance of a specific reaction mechanism in causing the total change of a certain phase solute. The formula can be defined as:

[0053]

[0054] Where, ΔC i is the total concentration change of the specific phase solute caused by the i-th reaction mechanism during the simulation period; Σ|ΔC j | is the sum of the absolute values ​​of the total concentration change caused by all reaction mechanisms j affecting the specific phase solute. The total concentration change here can be calculated within a specific time period or cumulatively.

[0055] Step 700: Identify the dominant reaction mechanism of the solute transformation under different sluice operation scenarios based on the contribution ratio.

[0056] By comparing the contribution ratios of different reaction mechanisms, we can identify the dominant mechanism that plays a decisive role in the transformation of a certain phase solute under a specific sluice operation scenario. In order to more clearly judge the strength of the dominant mechanism, we can set the level of contribution ratio. For example, the contribution ratio can be divided into multiple levels, such as "strong", "slightly strong", "basically unchanged", "slightly weak", "weak", and set the corresponding judgment interval. For example:

[0057] Table 1 Discrimination interval

[0058] grade Dominance discrimination interval powerful ＞0.40 Slightly stronger 0.20～0.40 basically unchanged 0.00～0.05 slightly weak 0.10～0.20 weak 0.05～0.10

[0059] The calculated contribution ratios of each reaction mechanism can be used to determine its dominance under the current sluice operation scenario. By comparing the dominant mechanism identification results under different operation scenarios, it is possible to clearly reveal how sluice operation changes the intrinsic driving force of solute transformation in the river.

[0060] The above methods can be used to determine the relative contributions of key reaction mechanisms to solute transformation (e.g., dissolved oxygen, dissolved organic matter, different forms of nitrogen, suspended solids concentration, etc.) under different sluice gate operation modes. For example, when the gate is closed and the flow rate is low, sedimentation and biochemical processes within the sediment (such as mineralization and denitrification) may become dominant; while when the gate is open and the discharge flow is large, resuspension at the interface between the water body and the sediment, nitrification in the water body, or adsorption / desorption processes may become more dominant. Understanding these dominant mechanisms helps to make informed decisions about how to operate the sluice gate to achieve desired water quality goals, such as minimizing pollutant accumulation upstream of the gate or controlling pollutant peaks downstream.

[0061] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A method for identifying the dominant mechanism of solute transformation in a gate-controlled river, characterized in that: The method comprises: Obtain basic data of the target gate-controlled river section; Constructing a solute multiphase transformation model covering the transformation processes of water, suspended matter and sediment based on the basic data; Set different sluice operation scenarios and reference scenarios, and simulate the temporal and spatial concentration changes of different phase solutes under each scenario; Calculate the total contribution rate of sluice operation and the contribution ratio of each reaction mechanism based on the solute multiphase transformation model; The dominant reaction mechanism of solute transformation under different scheduling scenarios is identified based on the contribution ratio.

2. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 1, characterized in that: The solute multiphase conversion model includes but is not limited to simulating one or more of the following reaction mechanisms: migration and diffusion, adsorption and desorption, sedimentation and resuspension, mineralization, nitrification and denitrification.

3. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 1, characterized in that: The total contribution rate of sluice operation and the contribution ratio of each reaction mechanism are calculated based on the solute multiphase conversion model as follows: Calculating the total contribution rate of sluice operation of each sluice operation scenario relative to the reference scenario based on the solute multiphase conversion model; According to the simulation process or simulation results of the solute multiphase conversion model, the contribution of each reaction mechanism affecting the concentration change of different phase solutes is separately calculated, and the contribution ratio of each reaction mechanism in the total contribution rate is calculated.

4. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 3, characterized in that: The calculation formula for the total contribution rate of sluice gate scheduling is: in, is the average concentration value of a phase solute under a certain sluice operation scenario; is the average concentration value of the solute in the phase without a gate or in the reference scenario.

5. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 3, characterized in that: The separate calculation of the contribution of each reaction mechanism affecting the concentration change of different phase solutes includes: separating the concentration change of a specific phase solute caused by each reaction mechanism within a unit time step or a simulation cycle from the calculation process of the solute multiphase conversion model.

6. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 3, characterized in that: The formula for calculating the contribution ratio of each reaction mechanism to the total contribution ratio is: Where, ΔC i is the total concentration change of the specific phase solute caused by the i-th reaction mechanism during the simulation period; Σ|ΔC j | is the sum of the absolute values ​​of the total concentration change caused by all reaction mechanisms j affecting the specific phase solute.

7. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 1, characterized in that: According to the contribution ratio, the dominant reaction mechanism of solute transformation under different scheduling scenarios is identified as follows: A grading standard for the contribution ratio is set, and the dominance of the reaction mechanism is determined based on the grading standard.

8. The method for identifying the dominant mechanism of solute transformation in gate-controlled rivers according to claim 1, characterized in that: The sluice gate scheduling scenarios include different gate opening modes and / or different gate opening degrees.

9. The method for identifying the dominant mechanism of solute transformation in a gate-controlled river according to claim 1, characterized in that: The basic data include river geometry data, hydrological data, meteorological data, water quality monitoring data and sediment characteristics data.

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