Method and system for constructing water pollution source emission inventory

Abstract

The application provides a construction method and a construction system of a water pollution source discharge list, and the method is applied to the intersection field of water environment management and geographic information system. The method firstly performs hydrological analysis on a region to be researched, divides sub-basins, generates a sub-basin layer and a sub-basin table, cuts each sub-basin into independent left and right bank catchment areas, and constructs left and right bank catchment layers. Then, an administrative region layer, a municipal drainage layer, the sub-basin layer and the left and right bank catchment layers are spatially intersected and overlaid to generate a calculation unit carrying four-dimensional attributes, the bank attribution of a pollution source is determined based on the calculation unit, and a tracing relationship table is constructed. Subsequently, taking the left and right bank catchment areas as the minimum units, the left and right bank sewage inflow amounts are calculated based on the left and right bank inflow coefficients respectively, and a discharge amount summary table is constructed. Finally, the pollution source discharge list containing a bank attribution field is generated according to the above tables, and the availability of the discharge list in water environment management is improved.

Description

Technical Field

[0001] This application relates to the interdisciplinary field of water environment management and geographic information systems, and more specifically, to a method and system for constructing a water pollution source discharge inventory in the interdisciplinary field of water environment management and geographic information systems. Background Technology

[0002] The water pollution source discharge inventory is the basic data for establishing the relationship between pollution sources and the water quality response of receiving water bodies, and it is an important support for scientific and precise pollution control.

[0003] Existing technologies construct spatial units by overlaying control section catchment areas and township administrative areas, and calculate pollution source emissions and inflows into rivers based on these spatial units as the smallest units to build pollution source emission inventories. In this process, the inflows of point source pollution sources and non-point source pollution sources are combined in the calculation. Existing pollution source emission inventories can distinguish which spatial unit the pollution source in the current river section originates from, but they cannot distinguish whether the pollution source from that spatial unit is located on the left or right bank of the river section. Therefore, it is impossible to accurately trace the specific flow path of the pollution source, resulting in low usability of the water pollution source emission inventory. Summary of the Invention

[0004] This application provides a method and system for constructing a water pollution source discharge inventory. The method divides a sub-basin into independent left-bank and right-bank catchment areas along the centerline of a river segment and performs spatial overlay. The calculation unit obtained after spatial overlay has a bank-specific attribute. The calculation unit serves as the smallest spatial unit for determining the pollution source discharge inventory. The bank-specific attribute of the calculation unit ensures that each table in the obtained pollution source discharge inventory contains a bank-specific attribute field, allowing for the calculation of pollution sources by bank, thus improving the usability of the water pollution source discharge inventory.

[0005] Firstly, a method for constructing a water pollution source emission inventory is provided. The method includes: performing hydrological analysis on a numerical elevation model of the area to be studied to divide the area into multiple sub-basins, and determining sub-basin layers and sub-basin tables based on the multiple sub-basins. Based on the centerline of the river section in the area to be studied, the sub-basin is divided into the left bank catchment area and the right bank catchment area, and the left and right bank catchment layers and tables are constructed based on the left and right bank catchment areas. Spatial intersection and overlay analysis is performed on the preset administrative region layer, preset municipal drainage layer, sub-basin layer and left and right bank water catchment layer to obtain calculation units, and a calculation unit table is constructed based on the bank attribute of the calculation units. Based on the computational unit table, the bank-specific attributes of point source pollution sources and non-point source pollution sources in the area to be studied are determined, and the source tracing relationship table is determined based on the bank-specific attributes of point source pollution sources and non-point source pollution sources. The source tracing relationship table is used to characterize the computational unit, catchment area and sub-basin to which point source pollution sources and non-point source pollution sources belong. The catchment area includes the left bank catchment area or the right bank catchment area. Based on the source tracing table, the preset left bank inflow coefficient and the preset right bank inflow coefficient, the sewage inflow from the left bank and the sewage inflow from the right bank are determined, and a discharge summary table is constructed based on the sewage inflow from the left bank and the sewage inflow from the right bank. Based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing table, and emission summary table, a pollution source emission inventory is determined.

[0006] In one possible implementation, the area under study includes multiple planning units, with any one of these planning units as the target planning unit. Based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing table, and emission summary table, a pollution source emission inventory is determined, including: Based on the source tracing table, the sewage discharge into the river from all left bank catchment areas within the target planning unit is summarized to obtain the sewage discharge into the river from the left bank of the target planning unit; and the sewage discharge into the river from all right bank catchment areas within the target planning unit is summarized to obtain the sewage discharge into the river from the right bank of the target planning unit. The total sewage inflow into the river is determined based on the sewage inflow from the left bank and the sewage inflow from the right bank for the target planning unit. The total amount of sewage discharged into the river was compared with the total amount of environmental sewage discharged in advance to obtain the comparison error; When the comparison error is less than the first preset threshold, the pollution source emission inventory is determined based on the actual measurement of sewage on the left bank and the actual measurement of sewage on the right bank, the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table.

[0007] In one possible implementation, a pollution source emission inventory is determined based on actual wastewater measurements from the left and right banks, sub-basin tables, left and right bank catchment tables, calculation unit tables, and source tracing tables, including: The first error was obtained by comparing the amount of sewage entering the river from the left bank with the actual measurement of sewage from the left bank. The second error was obtained by comparing the amount of sewage entering the river from the right bank with the actual measurement of sewage from the right bank. When either the first error or the second error is greater than or equal to the second preset threshold, the bank-specific attributes of point source pollution sources, the bank-specific attributes of non-point source pollution sources, the preset left bank inflow coefficient or the preset right bank inflow coefficient are adjusted, and the sub-basin table, left and right bank catchment tables, calculation unit table and source tracing relationship table are updated according to the adjusted information to update the pollution source emission inventory until both the first error and the second error are less than the second preset threshold.

[0008] In one possible implementation, the sub-basin is divided into a left-bank catchment area and a right-bank catchment area based on the centerline of the river segment in the area under study. Left and right bank catchment layers and tables are then constructed based on these areas, including: Based on the centerline of the river section, the sub-basin is divided into the left bank catchment area and the right bank catchment area according to the geometric difference method or the natural neighbor method. The bank attribute of the left bank catchment area is determined as left bank, and the bank attribute of the right bank catchment area is determined as right bank. Construct left and right bank water catchment layers based on the left and right bank water catchment areas; Based on the sub-basin coding and the bank-specific attributes of the catchment area, each left bank catchment area and right bank catchment area are coded to obtain the catchment area bank-specific coding; Based on the bank-specific code of the catchment area, the code of the sub-basin to which the catchment area belongs, and the area of ​​the catchment area, construct the left and right bank catchment tables.

[0009] In one possible implementation, based on a calculation unit table, the shore-based attributes of point source pollution sources and non-point source pollution sources within the study area are determined, including: For point source pollution sources, the coordinates of the corresponding sewage outlets of the point source pollution source are projected onto the centerline of the river section, and the bank-specific attribute of the point source pollution source is determined based on the riverbank where the projection point is located. For non-point source pollution sources, the shore attribute of the non-point source pollution source is determined based on the shore attribute of the computing unit where the non-point source pollution source is located.

[0010] In one possible implementation, the sewage discharge volume from the left bank and the sewage discharge volume from the right bank are determined based on a source tracing table, a preset left bank discharge coefficient, and a preset right bank discharge coefficient, including: Obtain the shore-specific attributes and wastewater discharge volume of all point source pollution sources, as well as the shore-specific attributes and wastewater discharge volume of non-point source pollution sources from the source tracing relationship table; The wastewater discharge from all point source and non-point source pollution sources with the bank-specific attribute of left bank is summarized to obtain the wastewater discharge volume of left bank. The wastewater discharge from all point source and non-point source pollution sources with the bank-specific attribute on the right bank is summarized to obtain the wastewater discharge volume on the right bank. The amount of sewage discharged from the left bank and the preset left bank inflow coefficient are used to determine the amount of sewage discharged from the left bank into the river. The amount of sewage discharged from the right bank and the preset right bank inflow coefficient are used to determine the amount of sewage discharged from the right bank into the river.

[0011] In one possible implementation, in the pollution source emission inventory, the field of the sub-basin code corresponding to the catchment area in the left and right bank catchment tables is used as a foreign key to associate with the sub-basin table, and the primary key of the left and right bank catchment tables is the field of the bank-specific code of the catchment area; the field of the sub-basin code corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the sub-basin table, and the field of the bank-specific code of the catchment area corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the left and right bank catchment tables; the source tracing relationship table includes pollution source bank-specific attributes.

[0012] In one possible implementation, the numerical elevation model is divided into multiple raster cells. Hydrological analysis is performed on the numerical elevation model of the study area to divide the study area into multiple sub-basins. Based on these sub-basins, sub-basin layers and sub-basin tables are determined, including: Hydrological analysis was performed on the numerical elevation model to determine the terrain type of each grid cell, including river network type and slope type. The river segment layer is determined based on the raster cells of the river network type terrain and the third preset threshold. Hydrological analysis was performed on the river section layer to obtain multiple sub-basins, which were then used to construct a sub-basin layer. Each sub-basin is coded to obtain a sub-basin table.

[0013] In one possible implementation, a spatial intersection and overlay analysis is performed on a preset administrative region layer, a preset municipal drainage layer, a sub-basin layer, and left and right bank catchment layers to obtain a calculation unit, including: Spatial intersection overlay analysis is performed on the preset administrative region layer, preset municipal drainage layer, sub-basin layer, and left and right bank catchment layers to obtain the intersection area; The calculation unit is obtained from the intersecting region.

[0014] Secondly, a system for constructing water pollution source emission inventories is provided, including: The analysis module is used to perform hydrological analysis on the numerical elevation model of the study area to divide the study area into multiple sub-basins, and to determine the sub-basin layers and sub-basin tables based on the multiple sub-basins. The processing module is used to divide the sub-basin into the left bank catchment area and the right bank catchment area based on the centerline of the river section in the area to be studied, and to construct the left and right bank catchment layers and the left and right bank catchment tables based on the left and right bank catchment areas. Spatial intersection and overlay analysis is performed on the preset administrative region layer, preset municipal drainage layer, sub-basin layer and left and right bank water catchment layer to obtain calculation units, and a calculation unit table is constructed based on the bank attribute of the calculation units. The processing module is used to determine the bank-specific attributes of point source pollution sources and non-point source pollution sources within the study area based on the calculation unit table, and to determine the source tracing relationship table based on the bank-specific attributes of point source pollution sources and non-point source pollution sources. The source tracing relationship table is used to characterize the calculation unit, catchment area and sub-basin to which point source pollution sources and non-point source pollution sources belong. The catchment area includes the left bank catchment area or the right bank catchment area. The processing module is used to determine the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank based on the source tracing relationship table, the preset left bank river entry coefficient and the preset right bank river entry coefficient, and to construct a discharge summary table based on the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank. The determination module is used to determine the pollution source emission inventory based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing relationship table, and emission summary table. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] Figure 1 A schematic diagram of a method for constructing a water pollution source emission inventory provided in this application embodiment. Figure 1 ; Figure 2 A schematic diagram of a method for constructing a water pollution source emission inventory provided in this application embodiment. Figure 2 ; Figure 3 A schematic diagram of a method for constructing a water pollution source emission inventory provided in this application embodiment. Figure 3 ; Figure 4 A schematic diagram of a method for constructing a water pollution source emission inventory provided in this application embodiment. Figure 4 ; Figure 5 A schematic diagram of a method for constructing a water pollution source emission inventory provided in this application embodiment. Figure 5 ; Figure 6 This is a schematic diagram of a system for constructing a water pollution source emission inventory, provided in an embodiment of this application.

[0017] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0018] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and B can represent: A alone, A and B simultaneously, and B alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0019] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0020] Before introducing the embodiments of this application, the technical terms used in the embodiments of this application will be explained first: Control section: This is a water quality monitoring cross section set up on the river channel. It is located downstream of the sewage confluence and at a position where sewage and river water are fully mixed. It is used to monitor the comprehensive water quality after the confluence of the entire river section and is the core point for watershed water quality assessment and pollution load verification.

[0021] Control unit: It is a water outflow node with a certain control section as the water outlet, and all tributaries eventually flow into the entire land catchment area of ​​that section. It is delineated by combining the natural watershed and the administrative boundaries of the township. It is the smallest control unit for pollution load accounting, water environment capacity allocation and the division of local pollution control responsibilities.

[0022] Next, the application background of the embodiments of this application will be explained: Pollution source emission inventories are the basic data for establishing the water quality response relationship between pollution sources and receiving water bodies, and are an important support for scientific and precise pollution control. In the prior art, a framework for calculating emissions and inflows into rivers has been established with "computation units" as the basic spatial units. This calculation unit is formed by superimposing the control section catchment area and the township administrative division, and a pollution source emission path analysis method has been constructed, which includes "pollution generation source, pollution emission path, pollution flowing into the river to the pollution inflow control section".

[0023] However, the aforementioned existing technologies have the following shortcomings in determining whether the pollution source originates from the left or right bank of the main river section: First, the bank-specific attribute of left bank and right bank is only defined as a spatial topological relationship description item or an attribute field on the record of sewage outlets into the river in the existing pollution source emission inventory. In the existing pollution source emission inventory, the bank-specific attribute is only a note for a certain control section or river segment, without spatial boundaries, and it is impossible to distinguish which specific water catchment areas belong to the left bank and which water catchment areas belong to the right bank.

[0024] Secondly, the catchment area of ​​the control section includes both the runoff generation area on the left bank and the runoff generation area on the right bank of the river. The emissions of point source pollution sources and non-point source pollution sources falling into the same calculation unit are mixed together for calculation, making it impossible to distinguish whether the specific source of pollutants appearing in the downstream of the river is a point source pollution source or a non-point source pollution source, whether the pollution source comes from the left bank catchment area or the right bank catchment area, and which sub-basin it originates from.

[0025] Furthermore, in the sewage flow path from point source pollution sources, pollution source discharge outlets, and sewage discharge outlets to the sewage receiving section, the bank-type attribute information only stays at the sewage discharge outlet node. That is, only the sewage discharge outlet has a bank-type attribute label. As for point source pollution sources and pollution source discharge outlets, they are not involved in bank-type attribute labels, which makes it impossible to determine the bank-type attributes of point source pollution sources and pollution source discharge outlets. In other words, it is impossible to determine the specific bank-type of the discharging pollution source based on the existing pollution source discharge inventory.

[0026] Finally, after non-point source pollution sources such as agricultural pollution sources, rural domestic pollution sources, and urban pollution sources are allocated to the corresponding control units by township, the control units span both banks of the river, making it impossible to achieve per-bank runoff allocation. This makes it difficult to cross-verify the pollution source emission inventory results with the pollution source emission results obtained from water environment numerical models based on the left or right bank, and thus the accuracy of the existing pollution source emission inventory cannot be determined.

[0027] In summary, most existing technologies construct spatial units by superimposing the catchment area of ​​the control section and the township administrative area, and calculate the discharge and inflow of pollution sources based on the spatial unit as the smallest unit to construct a pollution source discharge inventory. Among them, the inflow of point source pollution sources and non-point source pollution sources is combined in the calculation. The existing pollution source discharge inventory can distinguish which spatial unit the pollution source in the current river section originates from, but it cannot distinguish whether the pollution source from that spatial unit is located on the left bank or the right bank of the river section. Therefore, it is impossible to accurately trace the specific flow path of the pollution source, resulting in low usability of the water pollution source discharge inventory (hereinafter referred to as the pollution source discharge inventory).

[0028] To address the technical problems existing in related technologies, the inventors of this application propose the following approach: To address the low usability of existing pollution source emission inventories, this application first performs hydrological analysis on the digital elevation model of the study area to divide it into multiple sub-basins. Based on these sub-basins, sub-basin layers and sub-basin tables are determined. Then, using the river segment centerline as the dividing line, each sub-basin is divided along the river channel into left-bank and right-bank catchment areas using the buffer zone geometric difference method or the natural neighbor method, forming left and right bank catchment layers with unique codes and bank-specific attributes. On this basis, the four layers—preset administrative region layer, preset municipal drainage layer, sub-basin layer, and left and right bank catchment layers—are spatially intersected and overlaid to generate calculation units carrying four-dimensional attributes: administrative region affiliation, drainage affiliation, sub-basin affiliation, and left / right bank affiliation. Furthermore, based on the bank-specific attributes of the calculation units, the bank-specific affiliation of point source pollution sources and non-point source pollution sources is determined, constructing a source tracing relationship table. This table represents the calculation unit, catchment area, and sub-basin to which the pollution source belongs. Subsequently, using the catchment areas of the left and right banks as the smallest aggregation unit, and based on preset left-bank and right-bank inflow coefficients, the sewage inflow volumes from the left and right banks were determined, and a summary table of discharge volumes was constructed. Finally, based on the sub-basin table, left and right bank catchment tables, calculation unit table, and source tracing table, a refined pollution source discharge inventory including bank-specific attribute fields was determined. Thus, all four tables involved in the pollution source discharge inventory include bank-specific attribute fields, enabling accurate tracing of the specific flow paths of pollution sources by bank, thereby improving the usability of the pollution source discharge inventory. Simultaneously, since all four tables in the pollution source discharge inventory include bank-specific attribute fields, the inflow volume of a single bank can be determined based on the bank-specific attributes, and the single-bank inflow volume can be cross-checked with the measured single-bank inflow volume to update the pollution source discharge inventory and improve its accuracy, further enhancing the usability of the pollution source discharge inventory in refined water environment management.

[0029] Figure 1 This is a schematic diagram of a method for constructing a water pollution source discharge inventory provided in an embodiment of this application. Figure 1 ,like Figure 1 As shown, the method for constructing a pollution source emission inventory includes the following steps: Step 101: Perform hydrological analysis on the numerical elevation model of the study area to divide the study area into multiple sub-basins, and determine the sub-basin layers and sub-basin tables based on the multiple sub-basins.

[0030] In this step, hydrological analysis is performed on the numerical elevation model of the area under study. The digital elevation model includes multiple raster cells. Each raster cell is preprocessed, and then the runoff accumulation of the preprocessed raster cells is calculated. Raster cells with runoff accumulation greater than a third preset threshold are taken as river network raster cells. All river network raster cells are connected to obtain the river network. The river network is vectorized to obtain the river segment layer. Then, the pre-set control section is taken as the outlet point of the sub-basin. Hydrological analysis tools are used to divide the river segment layer to obtain multiple sub-basins. Based on the multiple sub-basins, the sub-basin layer and sub-basin table are determined.

[0031] The study area refers to the geographical region where a pollution source emission inventory needs to be established. The numerical elevation model of the study area is a raster elevation dataset extracted from publicly available datasets, using the geographical boundaries of the study area as the clipping range, and covering only the clipped range. A sub-basin is a closed catchment unit delineated through hydrological analysis based on the numerical elevation model of the study area. All precipitation or surface runoff within each sub-basin converges to the same outlet location through a catchment network. Adjacent sub-basins are separated by ridgelines or watersheds, do not overlap, and collectively cover the entire study area. The sub-basin layer is the result of organizing and managing all the above sub-basin regions as a unified GIS vector layer. Each feature in this layer (i.e., each sub-basin) corresponds to a record, associated with attribute information such as a unique code, area, outlet location, and vector geometric boundaries.

[0032] In one embodiment, the sub-basin table includes a sub-basin code, a river segment ID to which the sub-basin belongs, and a river segment length to which the sub-basin belongs, wherein the river segment ID and the river segment length to which the sub-basin belongs are determined based on the intersection relationship between the sub-basin and the river segment.

[0033] For example, the hydrological analysis algorithm can be a single-flow-direction algorithm, a multi-flow-direction algorithm, or a D-Infinity algorithm, etc., without specific limitations here.

[0034] Step 102: Based on the centerline of the river section in the area to be studied, the sub-basin is divided into the left bank catchment area and the right bank catchment area, and the left and right bank catchment layers and tables are constructed based on the left and right bank catchment areas.

[0035] In this step, the river segment centerline is first obtained. Then, using the river segment centerline as the basis for division, a Geographic Information System (GIS) geometric algorithm is employed to divide each sub-basin along the river segment centerline into left-bank and right-bank catchment areas. Each left-bank and right-bank catchment area is assigned a bank attribute, with the left-bank catchment area labeled as left bank (L) and the right-bank catchment area labeled as right bank (R). Subsequently, based on the divided left and right bank catchment areas, left and right bank catchment layers are constructed. Then, each left and right bank catchment area is encoded according to a preset format based on the sub-basin code (for example, SB-0001-L represents the catchment area of ​​the sub-basin SB-0001 located on the left bank, and SB-0001-R represents the catchment area of ​​the sub-basin SB-0001 located on the right bank), to obtain the bank code of the catchment area. Then, based on the bank code of the catchment area, the sub-basin code to which the catchment area belongs, the river segment code to which the catchment area belongs, and the area of ​​the catchment area, a left and right bank catchment table is established in a relational database.

[0036] The river segment centerline can be obtained by connecting the center points of the river network cross-sections in the river segment layer, or it can be extracted from the river segment layer using a GIS geometric algorithm for river centerlines. The GIS geometric algorithm used in this step can be either the geometric difference method or the natural neighbor method.

[0037] In one embodiment, the area under study is the coverage area of ​​a city along a river. Using the method described above, the area is divided into sub-basins along the river's centerline, resulting in 47 left-bank and 47 right-bank catchment areas. Each catchment area has independent geometric boundaries and bank-specific attribute markers. Based on this, the catchment areas are treated as independent geometric surface features, rather than the existing logical labels attached to control sections, river segments, or sewage outlets. This provides a geometric data foundation for the subsequent spatial overlay analysis of the left and right bank catchment areas as independent layers.

[0038] Step 103: Perform spatial intersection and overlay analysis on the preset administrative region layer, preset municipal drainage layer, sub-basin layer and left and right bank catchment layers to obtain calculation units, and construct a calculation unit table based on the bank attribute of the calculation units.

[0039] In this step, the first step is to obtain the preset administrative region layer and the preset municipal drainage layer for the area under study. The preset administrative region layer contains administrative boundary information at all levels, such as city, district / county, and township. The preset municipal drainage layer contains municipal drainage zoning boundary information for urban built-up areas. For non-built-up areas such as rural areas, farmland, and forests, which lack municipal drainage zoning information, sub-basin boundaries can be directly used to replace municipal drainage zoning. Then, the preset administrative region layer, the preset municipal drainage layer, the sub-basin layer, and the left and right bank catchment layers are subjected to intersection and overlay analysis. Each smallest broken polygon obtained from the intersection and overlay is defined as a computational unit. Since each computational unit inherits the bank-specific attributes from its respective left and right bank catchment layers, each computational unit carries a bank-specific label (i.e., L or R). Finally, a computational unit table is constructed based on all computational units and their attribute information.

[0040] In one embodiment, the calculation unit table records at least the unique code of each calculation unit, the township identifier, the drainage zone identifier, the sub-basin code, the catchment area code, the bank attribute, and the area of ​​the calculation unit.

[0041] Intersection overlay analysis involves geometrically intersecting the spatial extent of all polygons in the four layers to generate a set of minimum broken polygons. Each minimum broken polygon carries attribute information from four layers, specifically: township information from the preset administrative region layer, drainage zone information from the preset municipal drainage layer, sub-basin information from the sub-basin layer, and left and right bank catchment area information from the left and right bank catchment layers. By dividing the geographical areas on both sides of the river into different calculation units, the shortcomings of existing preset administrative region, preset municipal drainage, and sub-basin layer overlays that do not include bank-specific attribute analysis are fundamentally eliminated. This allows subsequent pollution source accounting to be performed on a single bank, further improving the accuracy of the pollution source emission inventory.

[0042] Step 104: Based on the calculation unit table, determine the shore-specific attributes of point source pollution sources and non-point source pollution sources within the area to be studied, and determine the source tracing relationship table based on the shore-specific attributes of point source pollution sources and non-point source pollution sources.

[0043] The source tracing table is used to characterize the calculation unit, catchment area, and sub-basin to which point source pollution sources and non-point source pollution sources belong. The catchment area includes the left bank catchment area or the right bank catchment area.

[0044] In this step, based on the shore-based attribute field in the calculation unit table, the shore-based attribute of the non-point source pollution source is read from the calculation unit table according to which calculation unit the non-point source pollution source is located on, and this shore-based attribute is used as the shore-based attribute of the non-point source pollution source. Point source pollution sources have fixed discharge outlet coordinates, and the shore-based attribute of point source pollution sources can be analyzed using GIS geometric algorithms.

[0045] After determining the shoreline attributes of all point source and non-point source pollution sources, a source tracing table is constructed based on the shoreline attributes of each pollution source and its corresponding computational unit, catchment area, and sub-basin information. The source tracing table records at least the unique identifier, pollution source type (i.e., point source or non-point source), shoreline attribute, computational unit identifier, catchment area shoreline code, and sub-basin code for each pollution source. Through the source tracing table, the emission shoreline of any pollution source and its hierarchical affiliation within the entire study area can be traced.

[0046] In one embodiment, the GIS geometric algorithm used in this step may be the vector cross product method or a built-in function of a GIS geometric algorithm, such as ArcGIS or PostGIS.

[0047] Step 105: Based on the source tracing relationship table, the preset left bank inflow coefficient and the preset right bank inflow coefficient, determine the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank, and construct a discharge summary table based on the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank.

[0048] In this step, the bank-specific attributes and wastewater discharge volumes (e.g., the total amount of pollutants such as ammonia nitrogen discharged from pollution sources) of all point source pollution sources, as well as the bank-specific attributes and wastewater discharge volumes of all non-point source pollution sources, are first obtained from the source tracing table. Then, the wastewater discharge volumes of all point source and non-point source pollution sources with the bank-specific attribute of left bank are summarized to obtain the total wastewater discharge volume on the left bank. Similarly, the wastewater discharge volumes of all point source and non-point source pollution sources with the bank-specific attribute of right bank are summarized to obtain the total wastewater discharge volume on the right bank. The wastewater discharge volume on the left bank is determined by multiplying the wastewater discharge volume on the left bank by a preset left bank inflow coefficient, and the wastewater discharge volume on the right bank is determined by multiplying the wastewater discharge volume on the right bank by a preset right bank inflow coefficient.

[0049] Furthermore, after calculating the wastewater discharge from the left bank and the right bank separately, a summary table of discharges is constructed based on these discharge volumes. This summary table includes at least the wastewater discharge volumes from the left and right banks, as well as the discharge volumes and bank-specific attributes for the catchment areas, control sections, compilation units, and the compilation scope. This allows for independent calculation of wastewater discharges from point source and non-point source pollution sources according to bank-specific attributes. The calculation results can then be directly compared with the actual monitored wastewater discharge volumes in the catchment areas of a single bank. Based on this comparison, the attribute information in the pollution source discharge inventory can be adjusted, thereby improving the accuracy and usability of the pollution source discharge inventory.

[0050] In one embodiment, the scope of the compilation refers to the entire geographical area of ​​the region to be studied. A compilation unit refers to several relatively independent sub-regions into which the scope of the compilation is divided according to certain rules (such as administrative divisions, watershed boundaries, drainage zones, etc.) to facilitate the work by dividing the area into zones and blocks.

[0051] In another embodiment, a certain planning area includes one planning unit, which contains two control sections (A and B). A includes a left-bank catchment area and a right-bank catchment area, and B includes a left-bank catchment area and a right-bank catchment area. The inflow of all left-bank catchment areas belonging to the same control section's catchment area is summed to obtain the left-bank inflow of the control section. Similarly, the inflow of all right-bank catchment areas belonging to the same control section's catchment area is summed to obtain the right-bank inflow of the control section. Further, the inflow of all left-bank catchment areas belonging to the same planning unit is summed to obtain the left-bank inflow of the planning unit. The inflow of all right-bank catchment areas belonging to the same planning unit is summed to obtain the right-bank inflow of the planning unit. Finally, the inflow of all left-bank catchment areas belonging to the same planning area is summed to obtain the left-bank inflow of the planning area. The inflow of all right-bank catchment areas belonging to the same planning unit is summed to obtain the right-bank inflow of the planning area. Finally, the inflow volume on the left bank of the control section, the inflow volume on the right bank of the control section, the inflow volume on the left bank of the planning unit, the inflow volume on the right bank of the planning unit, the inflow volume on the left bank of the planning scope, and the inflow volume on the right bank of the planning scope are stored in the following summary view of the discharge volume by bank.

[0052] Step 106: Determine the pollution source emission inventory based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing relationship table, and emission summary table.

[0053] In this step, the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing relationship table, and emission summary table are first obtained by forming a complete spatial data link through foreign key association, thus obtaining the pollution source emission inventory.

[0054] For example, in the pollution source emission inventory, the field of the sub-basin code corresponding to the catchment area in the left and right bank catchment tables is used as a foreign key to associate with the sub-basin table, and the primary key of the left and right bank catchment tables is the field of the bank code of the catchment area; the field of the sub-basin code corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the sub-basin table, and the field of the bank code of the catchment area corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the left and right bank catchment tables; the source tracing relationship table includes the pollution source bank attribute.

[0055] Among them, the emission summary table is the data query entry point for the pollution source emission inventory. All the bank-specific summary data in the inventory are obtained in real time from the sub-basin table, left and right bank catchment table, calculation unit table and source tracing relationship table through the emission summary table.

[0056] Then, based on the relationships between the aforementioned sub-basin tables, left and right bank catchment tables, calculation unit tables, and source tracing tables, the emission data and bank-specific attribute data of each pollution source are integrated with the data of their respective calculation units, catchment areas, and sub-basins. For example, for each pollution source, the bank-specific attribute and calculation unit identifier of the pollution source are obtained from the source tracing table; the bank-specific code and sub-basin identifier of the catchment area of ​​the calculation unit are obtained from the calculation unit table; the geometric boundary and area information of the catchment area are obtained from the left and right bank catchment tables; and the code and river segment information of the sub-basin are obtained from the sub-basin table. This information is then integrated with the emission and inflow data of each pollution source to form a complete pollution source emission data record. Finally, the integrated pollution source emission records of all pollution sources are organized and output according to a preset list format to obtain a pollution source emission list for the area under study. The pollution source emission list can be directly used for verifying the pollution source emission paths, left bank sewage inflow, and right bank sewage inflow against actual measurements.

[0057] In one embodiment, a pollution source emission inventory may include a basic pollution source table, a basic river segment table, a basic discharge outlet table, and a summary view of discharges by bank. The summary view of discharges by bank is a virtual statistical table generated in real time by using SQL queries to associate the bank-specific attributes in the source tracing table with the emission data in the basic pollution source table, grouping and summarizing the data by bank. For example, the contents of the sub-basin table, left and right bank catchment tables, calculation unit table, and source tracing table are as follows: Table 1: Sub-basin table

[0058] Table 2: Water Catch-up Tables for Left and Right Banks

[0059] Table 3: Calculation Unit Table

[0060] Table 4: Source Tracing Relationship Table

[0061] Of the four tables mentioned above, the pollution source basic table, river section basic table, and sewage outlet basic table were all obtained from publicly available datasets or collected from the field in the area under study.

[0062] In one embodiment, when a sudden increase in pollutant concentration is detected at the main control section, a summary view of discharges from each bank is retrieved. From this summary view, the identifier of the target river segment to which the control section belongs, the left bank inflow volume of that target river segment, and the right bank inflow volume of that target river segment are selected. If the left bank inflow volume is significantly higher than the right bank inflow volume, a source tracing table is further referenced. From this table, complete pollution source discharge data records for all sewage outlets and pollution sources on the left bank of the target river segment are selected. This accurately identifies polluting enterprises and agricultural non-point source pollution areas within the right bank catchment area, facilitating on-site investigation of pollution sources by staff.

[0063] Furthermore, such as Figure 2 As shown, the target compilation unit is any one of the multiple compilation units divided into the area to be studied. Based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing relationship table, and emission summary table, the pollution source emission inventory is determined. Step 106 specifically includes the following steps: Step 1061: Based on the source tracing table, summarize the sewage inflow of all left bank catchment areas within the target planning unit to obtain the sewage inflow of the left bank of the target planning unit, and summarize the sewage inflow of all right bank catchment areas within the target planning unit to obtain the sewage inflow of the right bank of the target planning unit.

[0064] Step 1062: Determine the total sewage inflow to the target planning unit based on the sewage inflow from the left bank and the sewage inflow from the right bank.

[0065] Step 1063: Compare the total amount of sewage entering the river with the total amount of environmental sewage discharged in advance to obtain the comparison error.

[0066] Step 1064: When the comparison error is less than the first preset threshold, determine the pollution source emission inventory based on the actual measurement of sewage on the left bank and the actual measurement of sewage on the right bank, the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table.

[0067] For example, the first preset threshold is preferably 20%, which can be adjusted according to actual management requirements.

[0068] In the above steps, firstly, the target compilation unit that needs to be summarized is determined. Using the source relationship table as the data source, all left-bank catchment areas belonging to the target compilation unit are selected. The sewage discharge volumes of these left-bank catchment areas are then summed to obtain the left-bank sewage discharge volume of the target compilation unit. Similarly, all right-bank catchment areas belonging to the target compilation unit are selected, and the sewage discharge volumes of these right-bank catchment areas are summed to obtain the right-bank sewage discharge volume of the target compilation unit.

[0069] In this application, the calculation results for each compilation unit are split into two independent components: left bank and right bank, providing a data foundation for subsequent bank-by-bank verification. This differs from existing technologies that only summarize the inflow volume by compilation unit without distinguishing between the inflow volume on the left and right banks, demonstrating the refined improvement in inflow volume calculation in this application.

[0070] Secondly, after obtaining the sewage inflow volumes from the left and right banks of the target planning unit, the two volumes are summed to obtain the total sewage inflow volume for that target planning unit. The total environmental pollution discharge volume for that target planning unit is then obtained from pre-collected data. The total sewage inflow volume is compared with this total environmental pollution discharge volume, and the percentage difference between the two is calculated as the comparison error.

[0071] Among them, the total amount of environmental pollutant discharge data can be obtained from authoritative data sources such as environmental statistics annual reports, pollutant discharge permit databases or pollution source censuses, which represent the statistical benchmark value of the total amount of pollutant discharge in the compilation unit.

[0072] Then, a total amount verification is performed between the total amount of pollution entering the river and the amount of pollution entering the river in the pollution source discharge inventory, that is, comparing the comparison error with a first preset threshold. When the comparison error is less than the first preset threshold, it indicates that the sewage discharge result calculated in this application has passed the credibility test. On this basis, a bank-specific verification mechanism is introduced, that is, comparing the sewage discharge volume on the left bank with the obtained actual sewage volume on the left bank, and comparing the sewage discharge volume on the right bank with the obtained actual sewage volume on the right bank. Only when the bank-specific verification is also passed, the pollution source discharge inventory containing bank-specific markers is finally determined and output based on the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table. Through the above-mentioned dual verification mechanism of total amount verification and bank-specific verification, the technical problem that bank-specific deviations cannot be detected by total amount verification alone in the prior art is solved, and the credibility of the pollution source discharge inventory is significantly improved.

[0073] Among them, the actual wastewater measurement on the left bank and the actual wastewater measurement on the right bank refer to the actual inflow data of the left and right banks obtained through single-bank measurement methods. These data can originate from measured data at single-bank water quality monitoring sections or from single-bank load estimates derived from single-bank water quality models. Specifically, a single-bank water quality model refers to a model that separately simulates the impact of the inflow load on water quality from the left bank and the impact of the inflow load on water quality from the right bank.

[0074] Furthermore, when the comparison error is less than the first preset threshold, a pollution source emission inventory is determined based on the actual measurements of sewage from the left bank and the right bank, the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table. Step 1064 may also include the following implementation methods: Step 10641: Compare the amount of sewage entering the river from the left bank with the actual measurement of sewage from the left bank to obtain the first error.

[0075] Step 10642: Compare the amount of sewage entering the river from the right bank with the actual measurement of sewage from the right bank to obtain the second error.

[0076] Step 10643: When either the first error or the second error is greater than or equal to the second preset threshold, adjust the bank-specific attributes of point source pollution sources, the bank-specific attributes of non-point source pollution sources, the preset left bank inflow coefficient or the preset right bank inflow coefficient, and update the sub-basin table, left and right bank catchment tables, calculation unit table and source tracing relationship table according to the adjusted information to update the pollution source emission inventory until both the first error and the second error are less than the second preset threshold.

[0077] The second preset threshold is preferably 30%, and its value can be adjusted adaptively according to actual management requirements, monitoring data quality and other factors.

[0078] In the above steps, the actual wastewater measurement on the left bank refers to the actual inflow data of the left bank into the river obtained through measurement methods independent of the calculation process, thus obtaining the actual wastewater measurement on the left bank of the target planning unit. Similarly, the actual wastewater measurement on the right bank refers to the actual inflow data of the right bank into the river obtained through measurement methods independent of the calculation process, thus obtaining the actual wastewater measurement on the left bank of the target planning unit. The wastewater inflow on the left bank is compared with the actual wastewater measurement on the left bank to obtain the first error, and the wastewater inflow on the right bank is compared with the actual wastewater measurement on the right bank to obtain the second error.

[0079] Then, the first error and the second error are compared with the second preset threshold, respectively. When both the first error and the second error are less than the second preset threshold, it indicates that the cross-bank verification has passed, that is, the calculation results of both the left and right banks are consistent with the measured values. At this time, the pollution source emission inventory can be confirmed as valid.

[0080] Specifically, when either the first error or the second error is greater than or equal to the second preset threshold, it indicates a discrepancy in the calculation results for one or both banks, requiring investigation and correction. The following priority order should be followed during the correction process: The first priority is to check the accuracy of the shore-based attribute assignments. This involves verifying whether there are any errors in the shore-based attributes of point source pollution sources and non-point source pollution sources. If errors are found, they should be corrected and the corresponding records in the source tracing table should be updated.

[0081] The second priority is to check the rationality of the inflow coefficient value. That is, to compare it with the standard value range in the industry guidelines, and to judge it in combination with the underlying surface conditions of regional ditches and ponds. When there is single-bank monitoring data, the inflow coefficient is reasonable if the error of the measured load rate meets the standard. If the inflow coefficient value is found to be inappropriate, the inflow coefficient of the corresponding bank is adjusted according to the single-bank measured rate rate results, and the corresponding record in the source tracing table is updated.

[0082] The third priority is to check the accuracy of the non-point source area weight allocation, that is, to verify whether there are any unreasonable spatial allocations in the process of allocating non-point source emissions according to the proportion of the calculation unit area to the township area. If so, the allocation weights are adjusted and the corresponding records in the source tracing relationship table are updated.

[0083] After completing the above investigation and correction, the sub-basin table, left and right bank catchment tables, calculation unit table and source tracing table are updated according to the adjusted information. The bank-by-bank calculation in step 105 and the verification process in steps 1061 to 10642 are re-executed until the first error and the second error are both less than the second preset threshold, and the final pollution source emission list is obtained. The pollution source emission list is corrected through steps 10641 to 10643 to improve the accuracy of the pollution source emission list.

[0084] Furthermore, based on the centerline of the river segment in the area under study, the sub-basin is divided into a left-bank catchment area and a right-bank catchment area. Left and right bank catchment layers and tables are then constructed based on these areas, such as... Figure 3 As shown, step 102 specifically includes the following implementation steps: Step 1021: Based on the centerline of the river section, divide the sub-basin into the left bank catchment area and the right bank catchment area according to the geometric difference method or the natural neighbor method, and determine the bank attribute of the left bank catchment area as left bank, and determine the bank attribute of the right bank catchment area as right bank.

[0085] Step 1022: Construct left and right bank water catchment layers based on the left and right bank water catchment areas.

[0086] Step 1023: Based on the sub-basin coding and the bank-specific attributes of the catchment area, code each left bank catchment area and right bank catchment area to obtain the catchment area bank-specific code.

[0087] Step 1024: Construct left and right bank catchment tables based on the bank code of the catchment area, the code of the sub-basin to which the catchment area belongs, and the area of ​​the catchment area.

[0088] The left and right bank catchment layers contain vector geometric boundary information for each left and right bank catchment area.

[0089] In one embodiment, when using the geometric difference method, a buffer zone with a very small width is first generated for the centerline of the river segment. The buffer zone is then subjected to a GIS difference operation with the sub-basin to obtain the remaining catchment area after removing the river channel. Then, based on the spatial position of each part in the remaining catchment area relative to the left or right side of the centerline of the river segment, it is determined whether the remaining catchment area belongs to the left bank or the right bank, thereby obtaining the left bank catchment area and the right bank catchment area.

[0090] In another embodiment, when using the natural neighbor method, sample points are set up on both sides of the controlled river section. The sample points are used as seed points to construct a natural neighbor map. The natural neighbor map divides the sub-basin into several natural neighbor units. Each natural neighbor unit corresponds to the nearest neighbor region of a seed point. The bank attribute of each grid unit is determined according to the bank attribute of the natural neighbor region to which each grid unit belongs. All grid units with the bank attribute of left bank are aggregated to form the left bank catchment area, and all grid units with the bank attribute of right bank are aggregated to form the right bank catchment area.

[0091] In steps 1022 to 1024, after determining the left and right bank catchment areas of the sub-basin, left and right bank catchment layers of the area under study are constructed based on the divided left and right bank catchment areas. Then, each left and right bank catchment area is coded separately. Specifically, the sub-basin code of the sub-basin to which the catchment area belongs is obtained, and the sub-basin code is combined with the bank attribute of the catchment area to generate the bank attribute code of the catchment area. For example, for a sub-basin with the sub-basin code "SB-001", the code of its left bank catchment area is "SB-001-L", and the code of its right bank catchment area is "SB-001-R", thus giving each left and right bank catchment area a globally unique identifier.

[0092] Based on this, according to the catchment area bank code, sub-basin code, and catchment area of ​​each catchment area, left and right bank catchment tables are constructed. The left and right banks are treated as geometric entities that can participate in spatial analysis independently, i.e., left and right bank catchment layers. This provides a core layer for the four-layer overlay analysis, so that the calculation units generated after the overlay analysis carry bank attributes, which facilitates the subsequent calculation of river inflow by bank. Based on the calculation results, the pollution source emission inventory is corrected, and the final corrected pollution source emission inventory has higher accuracy.

[0093] Furthermore, based on the calculation unit table, the shore-based attributes of point source pollution sources and non-point source pollution sources within the study area are determined, such as... Figure 4 As shown, step 104 specifically includes the following implementation steps: Step 1041: For point source pollution sources, project the coordinates of the corresponding sewage outlets of the point source pollution source onto the center line of the river section, and determine the bank-specific attribute of the point source pollution source based on the riverbank where the projection point is located.

[0094] Step 1042: For non-point source pollution sources, determine the shore attribute of the non-point source pollution source based on the shore attribute of the computing unit where the non-point source pollution source is located.

[0095] Step 1043: Determine the source tracing relationship table based on the shore-specific attributes of point source pollution sources and the shore-specific attributes of non-point source pollution sources.

[0096] In this step, for point source pollution sources with direct discharge outlets, a GIS geometric algorithm is used to automatically determine the bank-side attribute of the point source pollution source. Specifically, firstly, the coordinate data of the discharge outlets of each point source pollution source are obtained. For each discharge outlet into the river, based on the spatial distance between its coordinates and the centerline of each control river segment, a point-line distance matching algorithm is used to determine the control river segment to which the discharge outlet belongs. Then, the vertical projection point of the discharge outlet coordinates on the centerline of its river segment is calculated to determine the vertical landing point of the discharge outlet on the river segment. Afterwards, taking the vertical projection point as the starting point and taking the downstream direction along the centerline of the river segment, a flow direction vector is taken. Combined with the offset vector of the discharge outlet coordinates relative to the projection point, a cross product operation is used to determine whether the discharge outlet is located on the left or right side of the flow direction vector. Specifically, if the result of the cross product operation is greater than zero, the bank-side attribute of the point source pollution source is determined to be on the left bank; if the result of the cross product operation is less than or equal to zero, the bank-side attribute of the point source pollution source is determined to be on the right bank.

[0097] Furthermore, for point source pollution sources with indirect discharge outlets, such as those collected through pipelines and flowing into river outlets, the bank-side attribute of the nearest river outlet into which the point source pollution source flows is used as the bank-side attribute of the point source pollution source. For point source pollution sources that directly discharge into rivers, lakes, and reservoirs but are not registered in the river outlet registration database, the coordinates of the discharge outlet are first spatially matched with the records in the river outlet registration database. If no matching record is found, it is confirmed as an unregistered discharge outlet, and the aforementioned vector dot product algorithm and cross product operation process are reused to automatically determine its bank-side attribute based on the spatial geometric relationship between the coordinates of the unregistered discharge outlet and the river centerline. The entire discrimination process is executed in batches by GIS geometric algorithms, without the need for manual on-site annotation, ensuring the efficiency and consistency of bank-side attribute discrimination.

[0098] Since non-point sources have no fixed emission outlets, their shore-based attributes cannot be directly determined by projecting the coordinates of the emission outlets. Therefore, the spatial location of each non-point source pollution source is first determined. Then, based on which calculation unit the spatial location falls into, the shore-based attribute of that calculation unit is determined as the shore-based attribute of the non-point source pollution source. Finally, a source tracing relationship table is determined based on the shore-based attributes of point source pollution sources and non-point source pollution sources.

[0099] In steps 1041 to 1043 above, different determination schemes for point source pollution sources and non-point source pollution sources are distinguished. The bank affiliation of point source pollution sources is determined by the projection of the sewage outlet coordinates onto the center line of the river section. The bank affiliation of non-point source pollution sources is determined by the inheritance of the bank affiliation attribute of the calculation unit to which the non-point source pollution source belongs. The determination results are uniformly written into the source tracing relationship table, so that the bank affiliation information is completely transmitted along the source tracing link. This realizes the automated processing of bank affiliation and full-link traceability, and provides a data foundation that can be directly called for subsequent bank affiliation river inflow verification.

[0100] Furthermore, based on the source tracing table, the preset left bank inflow coefficient, and the preset right bank inflow coefficient, the sewage inflow from the left bank and the sewage inflow from the right bank are determined. Step 105 specifically includes the following implementation steps: Step 1051: Obtain the shore-specific attributes and wastewater discharge volume of all point source pollution sources, as well as the shore-specific attributes and wastewater discharge volume of non-point source pollution sources from the source tracing relationship table.

[0101] Step 1052: Summarize the wastewater discharge from all point source pollution sources and non-point source pollution sources whose shore attribute is left bank to obtain the wastewater discharge volume of left bank.

[0102] Step 1053: Summarize the wastewater discharge from all point source pollution sources and non-point source pollution sources whose shore attribute is right bank to obtain the wastewater discharge volume of right bank.

[0103] Step 1054: Determine the amount of sewage discharged from the left bank into the river based on the left bank sewage discharge volume and the preset left bank river inflow coefficient.

[0104] Step 1055: Determine the amount of sewage entering the river from the right bank based on the sewage discharge volume from the right bank and the preset right bank river inflow coefficient.

[0105] For example, the amount of sewage entering the river is the total amount of sewage from various types of wastewater and tributaries that eventually flow into the river. As sewage travels from the pollution source to the river, it will be lost through sedimentation in ditches, infiltration into the soil, and degradation in ponds and dams. Therefore, it is necessary to preset the inflow coefficient to balance the loss. The preset inflow coefficient represents the remaining proportion of sewage after the loss when it reaches the river.

[0106] In steps 1051 to 1055, firstly, the shore-specific attributes and wastewater discharge volumes of all point source pollution sources and all non-point source pollution sources are obtained from the source tracing table. Then, the wastewater discharge volumes of all point source and non-point source pollution sources with the shore-specific attribute on the left bank are summarized, yielding the total wastewater discharge volume on the left bank. Similarly, the wastewater discharge volumes of all point source and non-point source pollution sources with the shore-specific attribute on the right bank are summarized, yielding the total wastewater discharge volume on the right bank. Subsequently, based on the hydrogeological conditions and pollutant migration and transformation characteristics of the area under study, preset left bank inflow coefficients and preset right bank inflow coefficients are obtained. The total wastewater discharge volume on the left bank is multiplied by the preset left bank inflow coefficient to obtain the wastewater inflow volume on the left bank. Finally, the total wastewater discharge volume on the right bank is multiplied by the preset right bank inflow coefficient to obtain the wastewater inflow volume on the right bank. This enables independent accounting of point source pollutant and non-point source pollutant emissions in the left and right bank catchment areas, allowing the accounting results to be directly used for bank-specific verification and input into single-bank water quality models in subsequent steps.

[0107] Steps 1051 to 1055 above extract the pollution source discharge from the source tracing table by bank group, and multiply them by the preset left bank inflow coefficient and preset right bank inflow coefficient respectively to calculate the sewage inflow from the left bank and the sewage inflow from the right bank. This allows the left bank inflow and right bank inflow to be written into the source tracing table, facilitating the direct comparison of the calculation results with the actual inflow from the left and right banks respectively. This provides a data foundation for subsequent bank-specific inflow verification and single-bank water quality model docking.

[0108] Furthermore, the numerical elevation model is divided into multiple raster cells. Hydrological analysis is performed on the numerical elevation model of the study area to divide the study area into multiple sub-basins. Based on the multiple sub-basins, sub-basin layers and sub-basin tables are determined. Step 101 specifically includes the following implementation steps: Step 1011: Perform hydrological analysis on the numerical elevation model to determine the terrain type of each grid cell. The terrain type includes river network type and slope type.

[0109] Step 1012: Determine the river segment layer based on the raster cells of the river network type terrain and the third preset threshold.

[0110] Step 1013: Perform hydrological analysis on the river section layer to obtain multiple sub-basins, and construct sub-basin layers.

[0111] Step 1014: Encode each sub-basin to obtain the sub-basin table.

[0112] In steps 1011 to 1014, hydrological analysis tools are used to fill depressions in the raster cells of the numerical elevation model, eliminating false depressions and indentations caused by raster position errors, and removing the interference of topographic anomalies on the calculation of water flow direction and cumulative runoff, resulting in a depression-free numerical elevation model. Then, hydrological analysis algorithms are used to calculate the sewage flow direction of each raster cell, and based on the sewage flow direction of each raster cell, the cumulative runoff of sewage in each raster cell is calculated, which is the sum of the runoff from all upstream raster cells that ultimately flow into that raster cell along the sewage flow direction. When the cumulative runoff of a raster cell is greater than or equal to a third preset threshold, that raster cell is defined as a river network raster; otherwise, it is defined as a slope raster. All river network raster cells are connected to obtain river segments, which are then vectorized to construct a river segment layer. Finally, each river segment is coded to obtain a river segment ID.

[0113] The study uses a numerical elevation model without depressions as input and pre-defined control section locations as sub-basin outlet points. Hydrological analysis tools are employed to spatially segment the study area according to topographic watersheds, generating several independent, closed catchment units, each constituting a sub-basin. Sub-basin layers are then constructed, and each sub-basin is coded. Based on the intersection relationships between the sub-basins and river segments in the sub-basin layers, the river segment ID and length information of each sub-basin are determined. A sub-basin table is then constructed based on the sub-basin code, the river segment ID, and the river segment length information.

[0114] In steps 1011 to 1014 above, hydrological analysis is performed on the numerical elevation model to identify river network grids and slope grids. Based on the cumulative runoff of the river network grids and combined with a third preset threshold, the river segment layer is extracted. After further dividing the sub-basins, the sub-basins are coded, and then a sub-basin table is generated based on the sub-basin codes. This divides the area under study into several natural watershed units that can independently participate in spatial analysis and river inflow calculation, providing a basic data framework and correlation basis for the division of left and right banks, the division of calculation units, and the spatial attribution of pollution sources.

[0115] Furthermore, spatial overlay analysis is performed on the preset administrative region layer, preset municipal drainage layer, sub-basin layer, and left and right bank catchment layers to obtain calculation units, such as... Figure 5 As shown, step 103 specifically includes the following implementation steps: Step 1031: Perform spatial intersection overlay analysis on the preset administrative region layer, preset municipal drainage layer, sub-basin layer and left and right bank catchment layers to obtain the intersection area.

[0116] Step 1032: Obtain the calculation unit based on the intersecting region.

[0117] The preset administrative region layer includes the administrative boundaries of cities, districts / counties, and townships. The preset municipal drainage layer includes the drainage zone boundaries of urban built-up areas, while non-built-up areas are represented by the boundaries of their respective sub-basins.

[0118] In steps 1031 and 1032 above, the intersection overlay analysis involves geometrically intersecting the spatial extent of all polygons in the four layers to generate a set of minimum broken polygons, which constitute the intersection region. Each minimum broken polygon in the intersection region is defined as a calculation unit. Since the calculation unit inherits the bank-specific attributes from the left and right bank catchment layers after intersection overlay, each calculation unit carries a bank-specific marker, i.e., left bank or right bank. This allows subsequent calculations of the left bank inflow and right bank inflow based on the bank-specific marker, eliminating the shortcomings of existing technologies that directly merge and calculate inflow into the study area without distinguishing between left and right banks. This provides a refined calculation unit containing bank-specific attributes for subsequent pollution source tracing and bank-specific inflow calculation.

[0119] The following are system embodiments of this application, which can be used to execute the method embodiments of this application. For details not disclosed in the system embodiments of this application, please refer to the method embodiments of this application.

[0120] Figure 6 This is a schematic diagram of the structure of the water pollution source emission inventory construction system provided in the embodiments of this application. Figure 6 As shown, the system includes: Analysis module 601 is used to perform hydrological analysis on the numerical elevation model of the study area to divide the study area into multiple sub-basins, and to determine the sub-basin layer and sub-basin table based on the multiple sub-basins. The processing module 602 is used to divide the sub-basin into the left bank catchment area and the right bank catchment area based on the center line of the river section in the area to be studied, and to construct the left and right bank catchment layers and the left and right bank catchment tables based on the left and right bank catchment areas. Spatial intersection and overlay analysis is performed on the preset administrative region layer, preset municipal drainage layer, sub-basin layer and left and right bank water catchment layer to obtain calculation units, and a calculation unit table is constructed based on the bank attribute of the calculation units. The processing module 602 is used to determine the bank-specific attributes of point source pollution sources and non-point source pollution sources in the area to be studied based on the calculation unit table, and to determine the source tracing relationship table based on the bank-specific attributes of point source pollution sources and non-point source pollution sources. The source tracing relationship table is used to characterize the calculation unit, catchment area and sub-basin to which point source pollution sources and non-point source pollution sources belong. The catchment area includes the left bank catchment area or the right bank catchment area. The processing module 602 is used to determine the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank based on the source tracing relationship table, the preset left bank river entry coefficient and the preset right bank river entry coefficient, and to construct a discharge summary table based on the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank. The determination module 603 is used to determine the pollution source emission inventory based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing relationship table, and emission summary table.

[0121] In one possible implementation, the area to be studied includes multiple compilation units, with any one of these compilation units as the target compilation unit. A pollution source emission inventory is determined based on the sub-basin table, left and right bank catchment tables, calculation unit table, source tracing table, and emission summary table. The determination module 603 includes: Based on the source tracing table, the sewage discharge into the river from all left bank catchment areas within the target planning unit is summarized to obtain the sewage discharge into the river from the left bank of the target planning unit; and the sewage discharge into the river from all right bank catchment areas within the target planning unit is summarized to obtain the sewage discharge into the river from the right bank of the target planning unit. The total sewage inflow into the river is determined based on the sewage inflow from the left bank and the sewage inflow from the right bank for the target planning unit. The total amount of sewage discharged into the river was compared with the total amount of environmental sewage discharged in advance to obtain the comparison error; When the comparison error is less than the first preset threshold, the pollution source emission inventory is determined based on the actual measurement of sewage on the left bank and the actual measurement of sewage on the right bank, the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table.

[0122] In one possible implementation, a pollution source emission inventory is determined based on actual wastewater measurements from the left and right banks, a sub-basin table, left and right bank catchment tables, a calculation unit table, and a source tracing relationship table. The determination module 603 includes: The first error was obtained by comparing the amount of sewage entering the river from the left bank with the actual measurement of sewage from the left bank. The second error was obtained by comparing the amount of sewage entering the river from the right bank with the actual measurement of sewage from the right bank. When either the first error or the second error is greater than or equal to the second preset threshold, the bank-specific attributes of point source pollution sources, the bank-specific attributes of non-point source pollution sources, the preset left bank inflow coefficient or the preset right bank inflow coefficient are adjusted, and the sub-basin table, left and right bank catchment tables, calculation unit table and source tracing relationship table are updated according to the adjusted information to update the pollution source emission inventory until both the first error and the second error are less than the second preset threshold.

[0123] In one possible implementation, the sub-basin is divided into a left-bank catchment area and a right-bank catchment area based on the centerline of the river segment in the area to be studied. Left and right bank catchment layers and tables are then constructed based on these areas. The processing module 602 includes: Based on the centerline of the river section, the sub-basin is divided into the left bank catchment area and the right bank catchment area according to the geometric difference method or the natural neighbor method. The bank attribute of the left bank catchment area is determined as left bank, and the bank attribute of the right bank catchment area is determined as right bank. Construct left and right bank water catchment layers based on the left and right bank water catchment areas; Based on the sub-basin coding and the bank-specific attributes of the catchment area, each left bank catchment area and right bank catchment area are coded to obtain the catchment area bank-specific coding; Based on the bank-specific code of the catchment area, the code of the sub-basin to which the catchment area belongs, and the area of ​​the catchment area, construct the left and right bank catchment tables.

[0124] In one possible implementation, based on a calculation unit table, the shore-based attributes of point source pollution sources and non-point source pollution sources within the study area are determined. The determination module 603 includes: For point source pollution sources, the coordinates of the corresponding sewage outlets of the point source pollution source are projected onto the centerline of the river section, and the bank-specific attribute of the point source pollution source is determined based on the riverbank where the projection point is located. For non-point source pollution sources, the shore attribute of the non-point source pollution source is determined based on the shore attribute of the computing unit where the non-point source pollution source is located.

[0125] In one possible implementation, based on the source tracing table, a preset left bank inflow coefficient, and a preset right bank inflow coefficient, the sewage inflow from the left bank and the sewage inflow from the right bank are determined. The determining module 603 includes: Obtain the shore-specific attributes and wastewater discharge volume of all point source pollution sources, as well as the shore-specific attributes and wastewater discharge volume of non-point source pollution sources from the source tracing relationship table; The wastewater discharge from all point source and non-point source pollution sources with the bank-specific attribute of left bank is summarized to obtain the wastewater discharge volume of left bank. The wastewater discharge from all point source and non-point source pollution sources with the bank-specific attribute on the right bank is summarized to obtain the wastewater discharge volume on the right bank. The amount of sewage discharged from the left bank and the preset left bank inflow coefficient are used to determine the amount of sewage discharged from the left bank into the river. The amount of sewage discharged from the right bank and the preset right bank inflow coefficient are used to determine the amount of sewage discharged from the right bank into the river.

[0126] In one possible implementation, in the pollution source emission inventory, the field of the sub-basin code corresponding to the catchment area in the left and right bank catchment tables is used as a foreign key to associate with the sub-basin table, and the primary key of the left and right bank catchment tables is the field of the bank-specific code of the catchment area; the field of the sub-basin code corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the sub-basin table, and the field of the bank-specific code of the catchment area corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the left and right bank catchment tables; the source tracing relationship table includes pollution source bank-specific attributes.

[0127] In one possible implementation, the numerical elevation model is divided into multiple raster cells. Hydrological analysis is performed on the numerical elevation model of the area to be studied to divide the area into multiple sub-basins. Based on the multiple sub-basins, sub-basin layers and sub-basin tables are determined. The processing module 602 includes: Hydrological analysis was performed on the numerical elevation model to determine the terrain type of each grid cell, including river network type and slope type. The river segment layer is determined based on the raster cells of the river network type terrain and the third preset threshold. Hydrological analysis was performed on the river section layer to obtain multiple sub-basins, which were then used to construct a sub-basin layer. Each sub-basin is coded to obtain a sub-basin table.

[0128] In one possible implementation, a spatial intersection and overlay analysis is performed on a preset administrative region layer, a preset municipal drainage layer, a sub-basin layer, and left and right bank catchment layers to obtain a calculation unit. The processing module 602 includes: Spatial intersection overlay analysis is performed on the preset administrative region layer, preset municipal drainage layer, sub-basin layer, and left and right bank catchment layers to obtain the intersection area; The calculation unit is obtained from the intersecting region.

[0129] The system provided in this application embodiment can be used to execute the determination method in any of the above embodiments. Its implementation principle and technical effect are similar, and will not be described again here.

[0130] It should be noted that the division of the various modules in the above system is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, these modules can be implemented entirely in software through processing element calls; they can be implemented entirely in hardware; or some modules can be implemented through processing element calls in software, while others are implemented in hardware. Additionally, these modules can be integrated together or implemented independently. The processing element here can be an integrated circuit with signal processing capabilities. During implementation, the steps of the above method or the various modules can be completed through integrated logic circuits in the hardware of the processor element or through software instructions.

[0131] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for constructing a water pollution source emission inventory, characterized in that, The method includes: Hydrological analysis is performed on the numerical elevation model of the study area to divide the study area into multiple sub-basins, and sub-basin layers and sub-basin tables are determined based on the multiple sub-basins. Based on the centerline of the river section in the area to be studied, the sub-basin is divided into a left bank catchment area and a right bank catchment area, and left and right bank catchment layers and tables are constructed based on the left bank catchment area and the right bank catchment area. Spatial intersection and overlay analysis is performed on the preset administrative region layer, the preset municipal drainage layer, the sub-basin layer, and the left and right bank catchment layers to obtain calculation units, and a calculation unit table is constructed based on the bank attribute of the calculation units. Based on the calculation unit table, the bank-specific attributes of point source pollution sources and non-point source pollution sources within the area to be studied are determined, and a source tracing relationship table is determined based on the bank-specific attributes of the point source pollution sources and the non-point source pollution sources. The source tracing relationship table is used to characterize the calculation unit, catchment area, and sub-basin to which the point source pollution sources and non-point source pollution sources belong. The catchment area includes the left bank catchment area or the right bank catchment area. Based on the source tracing table, the preset left bank inflow coefficient and the preset right bank inflow coefficient, the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank are determined, and a discharge summary table is constructed based on the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank. Based on the sub-basin table, the left and right bank catchment tables, the calculation unit table, the source tracing table, and the emission summary table, a pollution source emission inventory is determined.

2. The method according to claim 1, characterized in that, The area to be studied includes multiple compilation units, with any one of these units being the target compilation unit. The process of determining the pollution source emission inventory based on the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table includes: Based on the source tracing table, the sewage discharge into the river from all the left bank catchment areas within the target planning unit is summarized to obtain the left bank sewage discharge into the river for the target planning unit; and the sewage discharge into the river from all the right bank catchment areas within the target planning unit is summarized to obtain the right bank sewage discharge into the river for the target planning unit. The total amount of sewage entering the river for the target planning unit is determined based on the sewage inflow from the left bank and the sewage inflow from the right bank. The total amount of sewage entering the river is compared with the total amount of environmental sewage discharged in advance to obtain the comparison error; When the comparison error is less than the first preset threshold, a pollution source emission inventory is determined based on the actual measurement of sewage on the left bank and the actual measurement of sewage on the right bank, the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table.

3. The method according to claim 2, characterized in that, The process of determining a pollution source emission inventory based on actual wastewater measurements from the left and right banks, the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing table includes: The first error is obtained by comparing the amount of sewage entering the river from the left bank with the actual measurement of sewage from the left bank. The second error is obtained by comparing the amount of sewage entering the river from the right bank with the actual measurement of sewage from the right bank. When either the first error or the second error is greater than or equal to the second preset threshold, the bank-specific attributes of the point source pollution source, the bank-specific attributes of the non-point source pollution source, the preset left bank inflow coefficient, or the preset right bank inflow coefficient are adjusted, and the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table are updated according to the adjusted information to update the pollution source emission inventory until both the first error and the second error are less than the second preset threshold.

4. The method according to claim 1, characterized in that, The sub-basin is divided into a left-bank catchment area and a right-bank catchment area based on the centerline of the river segment in the area under study, and left and right bank catchment layers and tables are constructed based on the left-bank and right-bank catchment areas, including: Based on the centerline of the river section, the sub-basin is divided into the left bank catchment area and the right bank catchment area according to the geometric difference method or the natural neighbor method. The bank attribute of the left bank catchment area is determined to be left bank, and the bank attribute of the right bank catchment area is determined to be right bank. Based on the left bank catchment area and the right bank catchment area, construct the left and right bank catchment layers; Based on the coding of the sub-basin and the bank-specific attributes of the catchment area, each left bank catchment area and each right bank catchment area are coded to obtain the bank-specific coding of the catchment area; Based on the bank-specific code of the catchment area, the code of the sub-basin to which the catchment area belongs, and the area of ​​the catchment area, a catchment table for the left and right banks is constructed.

5. The method according to claim 1, characterized in that, The determination of the shore-based attributes of point source pollution sources and non-point source pollution sources within the study area based on the calculation unit table includes: For the point source pollution source, the coordinates of the sewage outlet corresponding to the point source pollution source are projected onto the centerline of the river section, and the bank attribute of the point source pollution source is determined based on the riverbank where the projection point is located. For the non-point source pollution source, the shore attribute of the non-point source pollution source is determined according to the shore attribute of the computing unit where the non-point source pollution source is located; The source tracing relationship table is determined based on the shore-specific attributes of the point source pollution sources and the shore-specific attributes of the non-point source pollution sources.

6. The method according to claim 1, characterized in that, The determination of the sewage discharge volume from the left bank and the sewage discharge volume from the right bank based on the source tracing table, the preset left bank discharge coefficient, and the preset right bank discharge coefficient includes: Obtain the shore-specific attributes and wastewater discharge volume of all point source pollution sources, as well as the shore-specific attributes and wastewater discharge volume of non-point source pollution sources, from the source tracing relationship table; The wastewater discharge volume of the left bank is obtained by summing up the wastewater discharge volumes of all point source pollution sources and non-point source pollution sources whose bank-specific attributes are on the left bank. The wastewater discharge volume of the right bank is obtained by summing up the wastewater discharge volumes of all point source pollution sources and non-point source pollution sources whose bank-specific attributes are on the right bank. The amount of sewage discharged from the left bank and the preset left bank inflow coefficient are used to determine the amount of sewage discharged from the left bank into the river. The amount of sewage discharged from the right bank and the preset right bank inflow coefficient are used to determine the amount of sewage discharged from the right bank into the river.

7. The method according to claim 1, characterized in that, In the pollution source emission inventory, the field of the sub-basin code corresponding to the catchment area in the left and right bank catchment tables is used as a foreign key to associate with the sub-basin table, and the primary key of the left and right bank catchment tables is the field of the bank identification code of the catchment area; the field of the sub-basin code corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the sub-basin table, and the field of the bank identification code of the catchment area corresponding to the calculation unit in the calculation unit table is used as a foreign key to associate with the left and right bank catchment tables; the source tracing relationship table includes pollution source bank identification attributes.

8. The method according to claim 1, characterized in that, The numerical elevation model is divided into multiple raster cells. Hydrological analysis is performed on the numerical elevation model of the area under study to divide the area into multiple sub-basins. Based on these sub-basins, sub-basin layers and sub-basin tables are determined, including: Hydrological analysis is performed on the numerical elevation model to determine the terrain type of each grid cell, including river network type and slope type; The river segment layer is determined based on the grid cells of the river network type terrain and the third preset threshold. Hydrological analysis is performed on the river section layer to obtain multiple sub-basins, and the sub-basin layers are constructed accordingly. Each of the sub-basins is encoded to obtain the sub-basin table.

9. The method according to claim 1, characterized in that, The step involves performing spatial intersection and overlay analysis on the preset administrative region layer, the preset municipal drainage layer, the sub-basin layer, and the left and right bank catchment layers to obtain a calculation unit, including: Spatial intersection overlay analysis is performed on the preset administrative region layer, the preset municipal drainage layer, the sub-basin layer, and the left and right bank catchment layers to obtain the intersection area; The calculation unit is obtained based on the intersecting region.

10. A system for constructing a water pollution source emission inventory, characterized in that, The system includes: The analysis module is used to perform hydrological analysis on the numerical elevation model of the area under study, so as to divide the area under study into multiple sub-basins, and determine the sub-basin layer and sub-basin table based on the multiple sub-basins. The processing module is used to divide the sub-basin into a left bank catchment area and a right bank catchment area based on the center line of the river section in the area to be studied, and to construct left and right bank catchment layers and left and right bank catchment tables based on the left bank catchment area and the right bank catchment area. Spatial intersection and overlay analysis is performed on the preset administrative region layer, the preset municipal drainage layer, the sub-basin layer, and the left and right bank catchment layers to obtain calculation units, and a calculation unit table is constructed based on the bank attribute of the calculation units. The processing module is used to determine the bank-specific attributes of point source pollution sources and non-point source pollution sources in the area to be studied based on the calculation unit table, and to determine the source tracing relationship table based on the bank-specific attributes of the point source pollution sources and the non-point source pollution sources. The source tracing relationship table is used to characterize the calculation unit, catchment area and sub-basin to which the point source pollution sources and non-point source pollution sources belong. The catchment area includes the left bank catchment area or the right bank catchment area. The processing module is used to determine the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank based on the source tracing relationship table, the preset left bank river entry coefficient and the preset right bank river entry coefficient, and to construct a discharge summary table based on the amount of sewage entering the river from the left bank and the amount of sewage entering the river from the right bank. The determination module is used to determine the pollution source emission inventory based on the sub-basin table, the left and right bank catchment tables, the calculation unit table, and the source tracing relationship table.

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