Drainage basin water ecological function monitoring zoning method and device

Abstract

The invention relates to a watershed water ecological function monitoring zoning method and device. The method comprises the steps that digital elevation model data, land cover data, meteorological data and soil data of a target watershed are acquired; according to the digital elevation model data, performing sub-basin unit division on the target basin to obtain a plurality of sub-basin units and a water system network; determining an accumulated influence value of each sub-basin unit according to the water system network; evaluating the water ecological function of the target drainage basin by using an ecological system service and tradeoff comprehensive evaluation model to obtain a water yield index, a soil conservation index and a water quality purification index; according to the accumulated influence value, the soil conservation index, the water yield index and the water quality purification index, obtaining a water ecological function comprehensive index of each sub-basin unit; according to the water ecological function comprehensive index, water ecological function monitoring zoning is carried out on the target drainage basin, and pertinence of drainage basin water ecological function monitoring is improved.

Description

Technical Field

[0001] The present application relates to the technical field of water ecological monitoring, and in particular to a method and device for monitoring zoning of watershed water ecological functions. Background Art

[0002] In recent years, a variety of factors such as population growth, land use changes, and agricultural and urban expansion have led to rapid degradation and loss of water ecosystems and their ecological functions. Water ecological function monitoring is a key and basic link in achieving the protection and restoration of water ecological functions. A river basin is a relatively closed system with clear boundaries that exchanges matter, energy, and information with the outside world. Carrying out water ecological function monitoring in a river basin can comprehensively obtain basic information about the water ecosystem from the perspective of the system as a whole, and provide a scientific basis for the protection and restoration of water ecological functions in the river basin.

[0003] In related technologies, when conducting zoning monitoring of the water ecological functions of a river basin, insufficient consideration is given to the continuity, hierarchy and heterogeneity of the river basin, and the monitoring is not very targeted. Summary of the invention

[0004] Based on this, the purpose of this application is to provide a method and device for watershed water ecological function monitoring zoning, which can optimize the watershed water ecological function monitoring zoning, better adapt to the continuity, hierarchy and heterogeneity characteristics of the watershed, and improve the targeted nature of watershed water ecological function monitoring.

[0005] According to a first aspect of an embodiment of the present application, a method for monitoring and zoning water ecological functions in a watershed is provided, comprising the following steps: Obtain digital elevation model data, land cover data, meteorological data, and soil data of the target watershed; According to the digital elevation model data, the target watershed is divided into sub-watershed units to obtain several sub-watershed units and water system networks; According to the water system network, determine the cumulative impact value of each sub-basin unit; Using the comprehensive assessment model of ecosystem services and trade-offs, the water ecological function of the target watershed is evaluated based on digital elevation model data, land cover data, meteorological data, and soil data to obtain water yield indicators, soil conservation indicators, and water quality purification indicators; Based on the cumulative impact value, soil conservation index, water yield index and water purification index, the comprehensive index of water ecological function of each sub-basin unit is obtained; Based on the comprehensive index of water ecological function, the target river basin is zoned for water ecological function monitoring.

[0006] According to a second aspect of an embodiment of the present application, a watershed water ecological function monitoring zoning device is provided, comprising: A data acquisition module is used to obtain digital elevation model data, land cover data, meteorological data and soil data of the target watershed; The water system network acquisition module is used to divide the target watershed into sub-watershed units according to the digital elevation model data, and obtain several sub-watershed units and water system networks; The cumulative influence value acquisition module is used to determine the cumulative influence value of each sub-basin unit according to the water system network; The indicator acquisition module is used to evaluate the water ecological function of the target watershed using the comprehensive assessment model of ecosystem services and trade-offs, based on digital elevation model data, land cover data, meteorological data, and soil data, to obtain water yield indicators, soil conservation indicators, and water purification indicators; The index acquisition module is used to obtain the comprehensive index of water ecological function of each sub-basin unit according to the cumulative impact value, soil conservation index, water yield index and water quality purification index; The water ecological function monitoring zoning module is used to carry out water ecological function monitoring zoning of the target watershed according to the comprehensive water ecological function index.

[0007] The embodiment of the present application obtains digital elevation model data, land cover data, meteorological data and soil data of the target watershed; divides the target watershed into sub-watershed units according to the digital elevation model data to obtain a number of sub-watershed units and a water system network; determines the cumulative influence value of each sub-watershed unit according to the water system network; utilizes a comprehensive evaluation model of ecosystem services and trade-offs to evaluate the water ecological function of the target watershed according to the digital elevation model data, land cover data, meteorological data and soil data to obtain a water yield index, a soil conservation index and a water quality purification index; obtains a comprehensive water ecological function index of each sub-watershed unit according to the cumulative influence value, soil conservation index, water yield index and water quality purification index; and divides the target watershed into water ecological function monitoring zones according to the comprehensive water ecological function index. This application takes into account the propagation effect of rivers in the water network, and comprehensively evaluates the water ecological function of the basin by determining the cumulative influence value of the upstream sub-basin unit on the downstream sub-basin unit, the soil conservation index, water production index and water quality purification index of the sub-basin unit. It can accurately identify important areas of water ecological function in the basin, implement zoning monitoring, and improve the targeted monitoring.

[0008] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application.

[0009] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A schematic diagram of a flow chart of a method for monitoring and zoning water ecological functions in a watershed provided in one embodiment of the present application; Figure 2 A structural block diagram of a watershed water ecological function monitoring zoning device provided for one embodiment of the present application. DETAILED DESCRIPTION

[0011] In order to make the objectives, technical solutions and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0012] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0013] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0014] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0015] In addition, in the description of this application, unless otherwise specified, "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0016] See also Figure 1 , which is a flow chart of a method for monitoring and zoning water ecological functions in a watershed provided in an embodiment of the present application. The method for monitoring and zoning water ecological functions in a watershed provided in an embodiment of the present application comprises the following steps: S10: Acquire digital elevation model data, land cover data, meteorological data, and soil data of the target watershed.

[0017] Among them, the target watershed is the watershed where water ecological function monitoring zoning is to be carried out.

[0018] Digital Elevation Model (DEM) data, DEM data is a digital simulation of landforms through limited terrain elevation data.

[0019] Land cover data refers to the data information about the complex of natural and artificial creations covering the surface of the earth, which can reflect the quantity and spatial distribution characteristics of land cover types in the target watershed.

[0020] Meteorological data include precipitation data and evapotranspiration data; soil data include the content of sand, silt, clay, organic carbon, plant available water content data and limiting root depth data.

[0021] In an embodiment of the present application, digital elevation model data of the target watershed can be downloaded from the geospatial data cloud, land cover data of the target watershed can be obtained from the global land cover database, meteorological data of the target watershed can be obtained from the China Meteorological Data Network, and soil data of the target watershed can be obtained from the National Soil Database of China.

[0022] S20: Divide the target watershed into sub-watershed units according to the digital elevation model data to obtain a number of sub-watershed units and a water system network.

[0023] Among them, the sub-basin unit refers to the closed surface area through which surface runoff flows when it converges to a common outlet.

[0024] A water network refers to a river network system composed of numerous tributaries and main streams, which is gradually formed after a long period of erosion of the surface soil by surface runoff.

[0025] In the embodiment of the present application, hydrological analysis software can be used to process and analyze DEM data, divide the target watershed into sub-watershed units, and obtain multiple sub-watershed units and a water system network.

[0026] S30: Determine the cumulative influence value of each sub-basin unit based on the water system network.

[0027] Among them, the cumulative influence value is used to evaluate the cumulative influence of a sub-basin unit on the downstream sub-basin unit. The larger the cumulative influence value, the greater the cumulative influence of the sub-basin unit on the downstream sub-basin unit.

[0028] In the embodiment of the present application, the cumulative influence value of each sub-basin unit can be determined based on the number and flow direction of the main stream and each tributary in the water network, and the sub-basin units to which the main stream and the tributaries belong.

[0029] S40: Using the comprehensive assessment model of ecosystem services and trade-offs, the water ecological function of the target watershed is evaluated based on digital elevation model data, land cover data, meteorological data, and soil data to obtain water yield indicators, soil conservation indicators, and water purification indicators; Among them, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST model) aims to spatialize the quantitative evaluation of the value of ecosystem service functions by simulating the changes in the physical quantity and value of the ecosystem service system under different land cover scenarios, providing a scientific basis for decision makers to weigh the benefits and impacts of human activities.

[0030] Among them, the soil conservation index is used to evaluate the soil conservation function. The larger the value, the stronger the soil conservation function. The water yield index is used to evaluate the water yield function. The larger the value, the better the water yield function. The water purification index is used to evaluate the water purification function, which refers to the interception capacity of vegetation and soil for nutrients (nitrogen and phosphorus). The larger the value, the weaker the water purification capacity.

[0031] In an embodiment of the present application, the soil conservation function, water yield function and water quality purification function are evaluated based on the InVEST model to determine the soil conservation index, water yield index and water quality purification index of each sub-basin unit.

[0032] S50: Based on the cumulative impact value, soil conservation index, water yield index and water quality purification index, the comprehensive index of water ecological function of each sub-basin unit is obtained.

[0033] In an embodiment of the present application, corresponding weights are assigned to the cumulative influence value, soil conservation index, water production index and water quality purification index of each sub-basin unit, and the weights are used to perform weighted summation on the cumulative influence value, soil conservation index, water production index and water quality purification index of each sub-basin unit to obtain the comprehensive index of water ecological function of each sub-basin unit.

[0034] S60: Based on the comprehensive index of water ecological function, the target watershed is zoned for water ecological function monitoring.

[0035] In the embodiment of the present application, the index interval of the comprehensive index of the water ecological function of each sub-basin unit can be determined, and the water ecological function monitoring area of ​​each sub-basin unit can be determined according to the mapping relationship between the preset index interval and the water ecological function monitoring area. Among them, the water ecological function monitoring area includes extremely important water ecological function monitoring areas, important water ecological function monitoring areas and general water ecological function monitoring areas.

[0036] By using the embodiments of the present application, digital elevation model data, land cover data, meteorological data and soil data of the target watershed are obtained; according to the digital elevation model data, the target watershed is divided into sub-watershed units to obtain a number of sub-watershed units and a water system network; according to the water system network, the cumulative influence value of each sub-watershed unit is determined; using a comprehensive evaluation model of ecosystem services and trade-offs, the water ecological function of the target watershed is evaluated according to the digital elevation model data, land cover data, meteorological data and soil data to obtain water production indicators, soil conservation indicators and water quality purification indicators; according to the cumulative influence value, soil conservation index, water production index and water quality purification index, a comprehensive water ecological function index of each sub-watershed unit is obtained; according to the comprehensive water ecological function index, the target watershed is zoned for water ecological function monitoring. This application takes into account the propagation effect of rivers in the water network, and comprehensively evaluates the water ecological function of the basin by determining the cumulative influence value of the upstream sub-basin unit on the downstream sub-basin unit, the soil conservation index, water production index and water quality purification index of the sub-basin unit. It can accurately identify important areas of water ecological function in the basin, implement zoning monitoring, and improve the targeted monitoring.

[0037] In one embodiment, step S20 includes steps S201 to S206, which are specifically as follows: S201: Use the depression-filling tool of the hydrological analysis software to perform depression-filling processing on the digital elevation model data to obtain digital elevation model data without depressions.

[0038] In the embodiment of the present application, due to the terrain, there will be depressed areas in the DEM data. In the depressed areas, unreasonable or erroneous water flow direction data will be obtained. Therefore, before calculating the water flow direction data, the DEM data must be filled to obtain DEM data without depressions.

[0039] S202: Using the flow direction tool of the hydrological analysis software and the maximum slope method on the digital elevation model data without depressions, obtain the water flow direction data of each grid of the digital elevation model data without depressions.

[0040] Among them, the maximum slope method is a terrain analysis method used to calculate the water flow accumulation matrix. The water flow accumulation matrix refers to the cumulative value of water flowing from different locations into a specific point in an area. By calculating the water flow accumulation matrix, information such as the path of the water flow, the convergence area of ​​the water flow, and the direction of the water flow can be determined.

[0041] In the embodiment of the present application, the elevation difference of each grid is obtained through DEM data. The slope is determined according to the elevation difference. The flow direction of the water flow is determined according to the magnitude of the slope. In the maximum slope drop method, the basic principle of calculating the flow direction data of the water flow is that water flows to a lower place, and the flow direction is limited to flowing along the direction of the maximum slope, that is, the greater the slope, the easier it is for the water flow to flow to a lower place. S203: According to the water flow direction data of each grid, the flow tool of the hydrological analysis software is used to calculate the cumulative flow of the digital elevation model data without depressions.

[0042] Among them, in the process of surface runoff simulation, the runoff accumulation is calculated based on the water flow direction data. Specifically, there is a unit of water at each point in the digital ground elevation model represented by a grid. According to the natural law that water flows from high to low, the water flow value flowing at each point is calculated based on the water flow direction data of the regional terrain to obtain the runoff accumulation of the area.

[0043] In the embodiment of the present application, the water flow direction data of each grid is input into the flow tool of the hydrological analysis software to obtain the cumulative flow of the digital elevation model data without depressions.

[0044] S204: Based on the preset minimum cumulative runoff, using the grid calculator of the hydrological analysis software, extracting water network grid data from grids whose runoff accumulation is greater than the preset minimum cumulative runoff.

[0045] Among them, the minimum cumulative runoff determines the scope of the target watershed watershed unit division.

[0046] In the embodiment of the present application, the cumulative runoff of each grid is compared with the preset minimum cumulative runoff to determine the grid whose cumulative runoff is greater than the preset minimum cumulative runoff. The grid calculator of the hydrological analysis software is used to calculate these grids to obtain the target river network grid data.

[0047] S205: Use the vectorization tool of the hydrological analysis software to convert the water network raster data into a water network.

[0048] In an embodiment of the present application, water network raster data is vectorized to generate water network vector data, and the generated water network vector data is the required water network.

[0049] S206: Use the watershed tool of the hydrological analysis software to divide the water system network into sub-basin units to obtain a number of sub-basin units.

[0050] In an embodiment of the present application, the water system network is input into the watershed tool of the hydrological analysis software to obtain a number of sub-basin units.

[0051] By using the fill tool, flow direction tool, flow tool, raster calculator, vectorization tool and watershed tool of the hydrological analysis software, you can automatically and quickly obtain several water catchment units and water system networks.

[0052] In one embodiment, step S30 includes steps S301-S302, which are specifically as follows: S301: According to the water system network, the number of downstream sub-basin units through which the water system in the sub-basin unit flows is obtained; S302: Taking the number of downstream sub-basin units as the cumulative influence value of the sub-basin units.

[0053] In the embodiment of the present application, based on the water system network, the cumulative influence of the sub-basin unit is evaluated according to the cumulative number of sub-basin units downstream of the sub-basin unit. The more sub-basin units the water system in the sub-basin unit flows through, the greater the cumulative influence of the sub-basin unit on the downstream sub-basin units. Among them, the cumulative influence of the sub-basin unit without downstream is assigned a value of 0. For example, if the number of sub-basin units that the water system in the current sub-basin unit flows through downstream is 2, the cumulative influence value of the current sub-basin unit is 2.

[0054] The embodiment of the present application can automatically and quickly determine the cumulative influence value of the sub-basin unit by obtaining the number of downstream sub-basin units through which the water system in the sub-basin unit flows.

[0055] In one embodiment, the comprehensive assessment model of ecosystem services and trade-offs includes a water yield module, a sediment transport ratio module, and a nutrient transport ratio module. Step S40 includes step S401, which is as follows: S401: Inputting digital elevation model data, land cover data, meteorological data and soil data into a water yield module, a sediment transport ratio module and a nutrient transport ratio module to obtain water yield indicators, soil conservation indicators and water quality purification indicators.

[0056] The input data of the water yield module include but are not limited to precipitation, potential evapotranspiration, root depth, available moisture content of vegetation, etc. The input data of the sediment transport ratio module include but are not limited to digital elevation model data, soil texture data, land use data, and soil and water conservation measures. The input data of the nutrient transport ratio module include but are not limited to land use data, runoff potential index data, and nutrient transport coefficient.

[0057] In an embodiment of the present application, data required by the water production module, the sediment transport ratio module and the nutrient transport ratio module are obtained from digital elevation model data, land cover data, meteorological data and soil data. The water production module outputs a water production index, the sediment transport ratio module outputs a soil conservation index, and the nutrient transport ratio module outputs a water quality purification index.

[0058] In one embodiment, the water purification index includes a nitrogen purification evaluation value and a phosphorus purification evaluation value. Step S50 includes step S501, which is specifically as follows: S501: Perform weighted summation of the cumulative impact value, soil conservation index, water yield index, nitrogen purification assessment value, and phosphorus purification assessment value to obtain a comprehensive water ecological function index for each sub-basin unit.

[0059] In this embodiment of the present application, a weight of 0.25 is assigned to the cumulative influence value, soil conservation index and water yield index, and a weight of 0.125 is assigned to the nitrogen purification assessment value and the phosphorus purification assessment value, respectively. These weights are used to perform weighted summation on the cumulative influence value, soil conservation index, water yield index, nitrogen purification assessment value and phosphorus purification assessment value to obtain the comprehensive index of water ecological function of each sub-basin unit.

[0060] In one embodiment, step S60 includes step S601, which is specifically as follows: S601: Using the natural breakpoint method, the target river basin is divided into first-level water ecological function monitoring areas, second-level water ecological function monitoring areas and third-level water ecological function monitoring areas according to the comprehensive index of water ecological function; among them, the importance of the first-level water ecological function monitoring areas is greater than that of the second-level water ecological function monitoring areas, and the importance of the second-level water ecological function monitoring areas is greater than that of the third-level water ecological function monitoring areas.

[0061] Among them, the natural breakpoint method is to divide the data into several groups by finding natural breakpoints in the data (i.e. natural turning points or characteristic points of the data). The data in each group has similar properties, while the properties between groups are quite different. This method can maximize the differences between classes and help to better understand and analyze the data.

[0062] In the embodiment of the present application, after obtaining the comprehensive index of water ecological function of each sub-basin unit, the comprehensive index of water ecological function of each sub-basin unit is grouped by natural breakpoint method, and the sub-basin units of the same group are regarded as a water ecological function monitoring zone. Among them, the first-level water ecological function monitoring zone is a very important water ecological function monitoring zone, the second-level water ecological function monitoring zone is an important water ecological function monitoring zone, and the third-level water ecological function monitoring zone is a general water ecological function monitoring zone.

[0063] The following is an embodiment of the device of the present application, which can be used to execute the content of the method in the embodiment of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the content of the method in the embodiment of the present application.

[0064] See also Figure 2 , which shows a schematic diagram of the structure of a watershed water ecological function monitoring zoning device provided in an embodiment of the present application. The watershed water ecological function monitoring zoning device 7 provided in an embodiment of the present application includes: The data acquisition module 71 is used to acquire digital elevation model data, land cover data, meteorological data and soil data of the target watershed; The water system network acquisition module 72 is used to divide the target watershed into sub-watershed units according to the digital elevation model data, and obtain a plurality of sub-watershed units and a water system network; The cumulative influence value obtaining module 73 is used to determine the cumulative influence value of each sub-basin unit according to the water system network; An indicator acquisition module 74 is used to evaluate the water ecological function of the target watershed by using the comprehensive assessment model of ecosystem services and trade-offs based on digital elevation model data, land cover data, meteorological data, and soil data to obtain water yield indicators, soil conservation indicators, and water purification indicators; An index obtaining module 75 is used to obtain a comprehensive index of water ecological function of each sub-basin unit according to the cumulative impact value, soil conservation index, water yield index and water purification index; The water ecological function monitoring zoning module 76 is used to perform water ecological function monitoring zoning for the target watershed according to the comprehensive water ecological function index.

[0065] It should be noted that the watershed water ecological function monitoring zoning device provided in the above embodiment only uses the division of the above-mentioned functional modules as an example when executing the watershed water ecological function monitoring zoning method. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the watershed water ecological function monitoring zoning device provided in the above embodiment and the watershed water ecological function monitoring zoning method belong to the same concept, and the implementation process thereof is detailed in the method embodiment, which will not be repeated here.

[0066] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0067] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for monitoring and zoning water ecological functions in a watershed, characterized in that: The steps include: Obtain digital elevation model data, land cover data, meteorological data, and soil data of the target watershed; Dividing the target watershed into sub-watershed units according to the digital elevation model data to obtain a plurality of sub-watershed units and a water system network; Determining the cumulative influence value of each of the sub-basin units according to the water system network; Using a comprehensive assessment model of ecosystem services and trade-offs, the water ecological function of the target watershed is assessed based on the digital elevation model data, the land cover data, the meteorological data, and the soil data to obtain water yield indicators, soil conservation indicators, and water purification indicators; Obtaining a comprehensive water ecological function index for each sub-basin unit according to the cumulative influence value, the soil conservation index, the water yield index, and the water quality purification index; Based on the comprehensive index of water ecological function, the target watershed is zoned for water ecological function monitoring.

2. The method for monitoring and zoning water ecological functions in a watershed according to claim 1 is characterized by: The step of determining the cumulative influence value of each sub-basin unit according to the water system network comprises: According to the water system network, obtaining the number of downstream sub-basin units through which the water system in the sub-basin unit flows; The number of the downstream sub-basin units is taken as the cumulative influence value of the sub-basin units.

3. The method for monitoring and zoning water ecological functions in a watershed according to claim 1 is characterized by: The comprehensive assessment model of ecosystem services and trade-offs includes a water yield module, a sediment transport ratio module, and a nutrient transport ratio module; The step of using the comprehensive assessment model of ecosystem services and trade-offs to assess the water ecological function of the target watershed based on the digital elevation model data, the land cover data, the meteorological data, and the soil data to obtain water yield indicators, soil conservation indicators, and water purification indicators includes: The digital elevation model data, the land cover data, the meteorological data and the soil data are input into the water production module, the sediment transport ratio module and the nutrient transport ratio module to obtain water production indicators, soil conservation indicators and water quality purification indicators.

4. The method for monitoring and zoning watershed water ecological functions according to claim 1 is characterized by: The water purification index includes a nitrogen purification assessment value and a phosphorus purification assessment value; The step of obtaining the comprehensive index of water ecological function of each sub-basin unit according to the cumulative influence value, the soil conservation index, the water yield index and the water quality purification index comprises: The cumulative influence value, the soil conservation index, the water yield index, the nitrogen purification assessment value and the phosphorus purification assessment value are weightedly summed to obtain a comprehensive index of water ecological function of each sub-basin unit.

5. The method for monitoring and zoning watershed water ecological functions according to claim 1 is characterized by: The step of zoning the target watershed for water ecological function monitoring according to the comprehensive water ecological function index comprises: Using the natural breakpoint method, the target river basin is divided into first-level water ecological function monitoring areas, second-level water ecological function monitoring areas and third-level water ecological function monitoring areas according to the comprehensive water ecological function index; among which, the first-level water ecological function monitoring area is more important than the second-level water ecological function monitoring area, and the second-level water ecological function monitoring area is more important than the third-level water ecological function monitoring area.

6. The method for monitoring and zoning watershed water ecological functions according to any one of claims 1 to 5, characterized in that: The step of dividing the target watershed into sub-watershed units according to the digital elevation model data to obtain a plurality of sub-watershed units and a water system network comprises: Using a depression-filling tool of a hydrological analysis software to perform depression-filling processing on the digital elevation model data to obtain digital elevation model data without depressions; Using the flow direction tool of the hydrological analysis software to obtain the water flow direction data of each grid of the digital elevation model data without depressions by using the maximum slope drop method on the digital elevation model data without depressions; According to the water flow direction data of each grid, the flow accumulation of the digital elevation model data without depressions is calculated using the flow tool of the hydrological analysis software; Based on a preset minimum cumulative runoff, using a grid calculator of the hydrological analysis software, extracting water network grid data from grids whose confluence accumulation is greater than the preset minimum cumulative runoff; Using the vectorization tool of the hydrological analysis software to convert the water system network raster data into a water system network; The watershed tool of the hydrological analysis software is used to divide the water system network into sub-basin units to obtain a plurality of sub-basin units.

7. A watershed water ecological function monitoring zoning device, characterized in that: include: A data acquisition module is used to obtain digital elevation model data, land cover data, meteorological data and soil data of the target watershed; A water system network acquisition module is used to divide the target watershed into sub-watershed units according to the digital elevation model data, and obtain a plurality of sub-watershed units and a water system network; A cumulative influence value obtaining module, used for determining the cumulative influence value of each sub-basin unit according to the water system network; An indicator acquisition module is used to evaluate the water ecological function of the target watershed by using a comprehensive evaluation model of ecosystem services and trade-offs according to the digital elevation model data, the land cover data, the meteorological data and the soil data, and obtain a water yield index, a soil conservation index and a water purification index; An index obtaining module, used for obtaining a comprehensive water ecological function index of each sub-basin unit according to the cumulative influence value, the soil conservation index, the water yield index and the water quality purification index; The water ecological function monitoring zoning module is used to carry out water ecological function monitoring zoning for the target watershed according to the comprehensive water ecological function index.

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