A pollution reduction-based method for drawing a red line for protecting eutrophic lakes

Abstract

The application discloses a kind of based on pollution reduction eutrophic lake protection red line demarcation method, comprising: based on the concept of "source-harbor", construct lake alongshore land use classification system;Based on the high-resolution remote sensing image data and land use classification system of lake and surrounding area, create lake alongshore type identification search area;Based on the elevation characteristics in buffer zone, generate catchment area, combine land use classification system to calculate the pollution load production and reduction capacity of catchment area, determine its dominant attribute;Based on attribute, obtain continuous reduction source line frame, extract lakeside protection red line.The application is based on catchment unit and land use type eutrophic lake pollution simulation calculation method, determines the dominant attribute of catchment unit, extracts reduction unit from the perspective of environmental protection, realizes the demarcation of lakeside protection red line, and lays a foundation for scientific demarcation of protection red line and watershed land space planning.

Description

Technical Field

[0001] This invention relates to the field of lake protection technology, and in particular to a method for delineating protection red lines for eutrophic lakes based on pollution reduction. Background Technology

[0002] Lakes are nodes where various elements of the terrestrial surface system interact. They are important freshwater resource reservoirs, flood control reservoirs, and gene banks for species on Earth, closely related to human production and life. They play an irreplaceable role in maintaining the ecological balance of watersheds, meeting water needs for production and daily life, mitigating flood disasters, and providing abundant aquatic products. Eutrophication generally refers to a pollution phenomenon caused by human activities, resulting in an increase in nutrients in water bodies, excessive plant growth, and changes in the overall ecological balance of the aquatic body, thus causing harm. According to a survey on eutrophication of water bodies conducted by the United Nations Environment Programme (UNEP), 30% to 40% of lakes and reservoirs worldwide are affected to varying degrees, with significant differences in the extent of impact across different regions. With population growth and rapid economic development in lake basins and surrounding areas, pollutants such as total nitrogen (TN) and total phosphorus (TP) entering lakes are increasing. Large lakes and rivers generally have buffer zones at certain intervals to protect them from damage, disturbance, and pollution. These are often natural or man-made spaces, using strips or areas of land with permanent vegetation to intercept pollutants or harmful substances. The lakeshore protection red line, based on the concept of a buffer zone and referencing the concept of an ecological protection red line, is a spatial concept proposed for the special area of ​​the lakeshore to facilitate pollutant control. Within the lakeshore protection red line, the focus is on the protection of lake water environment, and strict control is exercised over pollution discharge. Delineating lakeshore protection red lines for urban lakes with high human activity can protect the lake's isolated habitat, mitigate or reduce the damage, disturbance, and pollution to the lake's aquatic ecosystem caused by various human activities or natural processes within the watershed. It holds a particularly important position in the spatial layout of lake watersheds and is of great significance for ensuring the generation, confluence, and delivery of clean water into the lake, safeguarding the ecological health of the watershed, and maintaining the quality of the lake's water environment.

[0003] Existing lake buffer spaces often use simple distance buffering methods, which cannot be adapted to local conditions to maximize protection strategies. Currently, there are three main methods for delineation: (1) the method based on complex mathematical models, which simulates the entire process of sediment and pollutant deposition and migration in the riparian buffer zone. However, this method requires continuous observation data of multiple parameters. There is a lack of basic data for riparian zone research in China, and it is difficult to obtain. This limits the promotion and application of this type of model to a certain extent; (2) the method based on simple mathematical models involves fewer spatial variables and can simply and quantitatively calculate the width of the lake buffer space; (3) other methods for determining the width of the buffer space are determined by different methods depending on the specific application purpose. This invention overcomes the dilemma faced by previous lake water environment management and protection. From the perspective of lake water environment protection, it proposes a method for setting up a spatial control range of physical isolation—the lake protection red line, and based on natural water catchment units, establishes a quantitative and automatic method for extracting and delineating the lake protection red line range. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by this invention is that current methods for delineating lake shorelines mainly focus on small-scale ecosystem restoration design, which cannot meet the requirements for the protection of eutrophic lakes.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for delineating the protection red line of eutrophic lakes based on pollution reduction, comprising:

[0008] Based on the concept of "source-sink", a land use classification system for lake shores based on pollution reduction is constructed;

[0009] Based on high-resolution remote sensing image data of the lake and its surrounding areas and the aforementioned land use classification system, a search area for identifying land use types along the lake shore is created.

[0010] Based on the elevation characteristics within the buffer zone, a catchment area is generated, and based on the land use classification system, the pollution load generation and reduction capacity of each catchment area are calculated to determine the dominant attribute of the unit.

[0011] Based on the aforementioned properties, the continuous cut-off unit line border is obtained, and the lakeside protection red line boundary is extracted.

[0012] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes described in this invention, the land use classification system includes:

[0013] The land along the lake is divided into ecological, residential, and productive types. The ecological type includes mountain, wetland, and estuary types; the residential type includes rural and urban types; and the productive type includes arable land and construction land types.

[0014] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes according to the present invention, the concept of "source-sink" includes:

[0015] The sources of nitrogen and phosphorus pollutants in water bodies are called "sources". In contrast to "sources", "sinks" refer to some regions or ecosystem types that can absorb nitrogen and phosphorus pollutants. The living and productive types in the land classification of the lake shore are regarded as the "sources" of lake eutrophication, and the ecotypes in the land classification of the lake shore are regarded as the "sinks" of lake eutrophication.

[0016] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes described in this invention, the high-resolution remote sensing image data and land use classification system include:

[0017] Based on the lake's water level records, high-resolution remote sensing image data corresponding to the period of highest water level in a year are selected. The high-resolution remote sensing images are loaded using software, and the highest water level line of the lake and the surrounding land use system are obtained based on the remote sensing images.

[0018] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes according to the present invention, the step of creating a search area for lake shoreline utilization type identification includes:

[0019] The software loads linear lake boundary data and uses it as the lower boundary of the lake shore protection red line, and creates a buffer zone outward based on the highest water level.

[0020] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes according to the present invention, the method for generating catchment areas includes:

[0021] Based on digital elevation data of the lake and its surrounding area, software analysis tools are used to analyze flow direction, depression filling, flow rate, river network, and catchment area, thereby creating a watershed area with isometric features.

[0022] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes according to the present invention, the calculation of the pollution load generation and reduction capacity of each catchment area includes:

[0023] Calculate the pollution load generated by land use types of residential or industrial use along the lake shore, and calculate the pollution load reduction by land use types of ecological use along the lake shore.

[0024] As a preferred embodiment of the method for delineating the protection red line of eutrophic lakes based on pollution reduction described in this invention, the calculation of pollution load generation and reduction capacity includes:

[0025] The method for calculating the pollution load generated by urban and rural residential activities is as follows: combining the average mass concentration of each pollutant in rainfall-runoff events obtained from rainfall-runoff monitoring, the formula is expressed as:

[0026] L = 0.001 × EMC × R × A built ×P1

[0027] Where L is the pollution load generated by urban and rural land use, kg; EMC is the average concentration per rainfall, mg / L, based on field sampling; R is the annual runoff coefficient; P1 is the multi-year average rainfall, mm; A built The area of ​​construction land within the catchment area, in km² 2 ;

[0028] The method for calculating the pollution load generated by farmland production is as follows: Based on the principle of conservation of mass, the surplus or deficit of the average annual nitrogen and phosphorus nutrient load of farmland is quantitatively described and used as the farmland pollution source load in the model. The formula is expressed as follows:

[0029] P2 = Input × A crop ×r

[0030] Wherein, P2 represents the pollution load generated by cultivated land use, in kg; Input represents the annual net fertilizer application per unit of land, in t / km². 2 A crop The area is expressed as cultivated land within the catchment area, in km². 2 ; r This is expressed as the churn coefficient;

[0031] The calculation method for the reduction of pollution load in wetland ecosystems is as follows: The calculation is based on empirical values ​​of pollution load from wetland technical specifications and wetland monitoring data, expressed by the following formula:

[0032] W=A wet × x ×365*0.001

[0033] x =(mi-mo) / d *

[0034] Wherein, W represents the annual absorption capacity of wetland-type pollution load within the catchment area, in kg; xExpressed as pollutant absorption capacity, g / m 2 ·d; * indicates the wetland monitoring formula, mi represents the water quality at the wetland inlet, mo represents the water quality at the lake outlet, and A wet Indicates the area of ​​arable land within the catchment area, in km². 2 d represents the number of days;

[0035] The calculation method for the reduction of ecological pollution load in forest land is as follows: referring to the reduction parameters of similar typical forest land in China, the formula is expressed as:

[0036] F=A forest × u ×365*0.001

[0037] Wherein, F: annual absorption capacity of forest-type pollution load within the catchment area, kg; u: pollutant absorption capacity, g / m³ 2 ·d, A forest Area of ​​cultivated land within the catchment area, km² 2 .

[0038] As a preferred embodiment of the pollution reduction-based method for delineating protection red lines for eutrophic lakes described in this invention, the dominant attributes include: pollution-generating units, balance units, and reduction units; the criteria for determining the three dominant attributes are as follows:

[0039] Pollution-generating unit: Pollution load generation within the catchment area > pollution load reduction capacity;

[0040] Balance unit: Pollution load generation within the catchment area = pollution load reduction capacity;

[0041] Reduction unit: Pollution load generation in the catchment area < pollution load reduction capacity.

[0042] As a preferred embodiment of the pollution reduction-based method for delineating the protection red line of eutrophic lakes according to the present invention, the step of extracting the lake shore protection red line boundary includes:

[0043] All reduction units were extracted, and nearest neighbor analysis was performed using software analysis tools to extract the nearest reduction unit along the lake. The upper boundary of the lake protection red line was obtained by drawing a continuous line based on its outer boundary. The upper boundary was then interpreted in conjunction with high-resolution imagery and adjusted according to the actual situation around the lake. Finally, the upper and lower boundaries were combined to form the lake shore protection red line.

[0044] The beneficial effects of this invention are as follows: This invention constructs a land use classification system for lake shorelines based on high-resolution remote sensing image interpretation for pollution reduction; it delineates research units according to the elevation distribution and catchment characteristics around eutrophic lakes, and uses catchment areas with catchment characteristics to delineate lake shore protection red lines; based on the pollution simulation calculation method of eutrophic lakes using catchment units and land use types, it determines the dominant attributes of catchment units, extracts reduction units from the perspective of environmental protection, and designs a method for delineating lake shore protection red lines, laying the foundation for the scientific delineation of protection red lines for lakes and watershed territorial spatial planning. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0046] Figure 1 A flowchart illustrating an overall process for delineating protection red lines for eutrophic lakes based on pollution reduction, as provided in one embodiment of the present invention.

[0047] Figure 2 A distribution diagram of pollution-generating units, reduction units, and balancing units in Dianchi Lake provided according to an embodiment of the present invention;

[0048] Figure 3 This is a preliminary extraction result diagram of the Dianchi Lake protection red line provided in one embodiment of the present invention. Detailed Implementation

[0049] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0050] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0051] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0052] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0053] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] Example 1

[0056] Reference Figure 1 As an embodiment of the present invention, a method for delineating protection red lines for eutrophic lakes based on pollution reduction is provided, comprising:

[0057] S1: Based on the concept of "source-sink", construct a land use classification system for lake shores based on pollution reduction;

[0058] It is important to know that the source of nitrogen and phosphorus pollutants in water bodies is called a "source". In contrast to a "source", a "sink" refers to some regions or ecosystem types that can absorb nitrogen and phosphorus pollutants. The living and productive types in the land classification of the lake shore are regarded as the "source" of lake eutrophication, and the ecotypes in the land classification of the lake shore are regarded as the "sink" of lake eutrophication.

[0059] Furthermore, the land along the lake shore is divided into ecological, residential, and productive types; among them, the residential and productive types serve as the "source" of lake eutrophication, while the ecological type serves as the "sink" of lake eutrophication.

[0060] It should be noted that the ecological type includes mountain type, wetland type, and estuary type; the living type includes rural type and urban type; and the production type includes arable land type and construction land type.

[0061] Furthermore, a land use classification system for lake shorelines based on pollution reduction was constructed, as shown in Table 1;

[0062] Table 1. Land use classification system along lake shores based on pollution reduction

[0063]

[0064] S2: Based on high-resolution remote sensing image data and land use classification data of the lake and its surrounding areas, create a search area for identifying land use types along the lake shore.

[0065] Furthermore, based on the lake water level records, select the corresponding high-resolution remote sensing image data (images) for the period of highest water level in a year, create a new project file using ArcGIS software, and load the high-resolution remote sensing image data (Images). The resolution of the remote sensing images should be better than 2m.

[0066] It should be noted that when delineating the protection red line for lakes, the lower boundary of the protection red line needs to be determined based on the highest water level of the lake. Therefore, when selecting high-resolution remote sensing image data, it is necessary to select the data corresponding to the highest water level period of the year based on the lake water level record in order to obtain the highest water level data of the lake.

[0067] Furthermore, based on high-resolution remote sensing images, the highest water level of the lake and land use data along the lake shore were extracted. The linear feature lake boundary data (SHP linear format) L_lower was loaded using ArcGIS software as the lower boundary of the protection red line. A strip-shaped buffer P_buffer was created outward from the highest water level.

[0068] It should be noted that the width of the strip buffer zone (generally 300-500 meters) should be reasonably set according to the size of the lake. This area is the search area for identifying the utilization type along the lake shore. This area is the maximum delineation range of the lake protection red line. The subsequent delineation of the catchment area and the calculation of regional nitrogen and phosphorus pollutant emission characteristics will be carried out within this range.

[0069] S3: Based on the elevation characteristics within the buffer zone, generate catchment areas, and calculate the pollution load generation and reduction capacity of each catchment area based on the land use classification data, and determine the dominant attribute of the unit;

[0070] Furthermore, digital elevation data of the lake and its surrounding area are loaded, and ArcGIS software analysis tools are used to analyze flow direction, depression filling, flow rate, river network, and catchment area, thereby creating a surface feature catchment area (SHP linear format) P_watershed;

[0071] It should be noted that the same unit has the same water catchment direction and characteristics.

[0072] Furthermore, land use data is loaded, land use type is extracted for each watershed P_watershed, and based on the land use type and area of ​​each watershed, the pollution load generation and pollution load reduction capacity in each watershed are calculated. The pollution simulation calculation methods for different land use classification systems are shown in Table 2.

[0073] Table 2. Pollution Simulation Calculation Methods for Different Land Use Classification Systems

[0074]

[0075] It should be noted that the pollution load generation is calculated for the land use types that generate pollution, and the pollution load reduction is calculated for the land use types that absorb pollution. The main types for which the pollution load generation needs to be calculated are urban and rural residential land and cultivated land production land, while the main types for which the pollution load reduction needs to be calculated are wetland ecological land and forest ecological land.

[0076] Furthermore, the dominant attributes of a unit are determined based on the amount of pollution load generated and the capacity to reduce pollution load within the catchment area.

[0077] It should be noted that the dominant attributes mainly include pollution-generating units, balancing units, and reduction units; the criteria for determining pollution-generating units are: pollution load generation in the catchment area > pollution load reduction capacity; the criteria for determining balancing units are: pollution load generation in the catchment area = pollution load reduction capacity; and the criteria for determining reduction units are: pollution load generation in the catchment area < pollution load reduction capacity.

[0078] S4: Based on the aforementioned attributes, obtain the continuous cut-off unit line border and extract the lakeside protection red line boundary.

[0079] Furthermore, based on the attributes of each unit, all reduction units are extracted, and nearest neighbor analysis is performed using ArcGIS software analysis tools to extract the nearest reduction unit along the lake. Based on its outer boundary, continuity is drawn to obtain the upper boundary L_upper of the lake protection red line.

[0080] It should be noted that, according to the definition of a reduction unit, the catchment area of ​​a reduction unit mainly functions to absorb and purify nitrogen and phosphorus pollutants in the water. Therefore, in order to maximize the protection of the natural purification capacity of the catchment area around the lake, all reduction units along the lake are extracted here as the boundary of the lake shore protection red line.

[0081] Furthermore, by combining high-resolution imagery for interpretation and adjusting L_upper according to the actual situation around the lake, and combining it with L_lower obtained based on the highest water level of the lake, a lakeshore protection red line is formed.

[0082] It should be noted that the interpretation based on the impact of high scores and the adjustments made according to the actual situation are for the purpose of reviewing the delineated lakeside protection red line to ensure its accuracy.

[0083] Furthermore, use ArcGIS's New Database feature to store all the above data in a database.

[0084] Example 2

[0085] Reference Figure 2 As an embodiment of the present invention, a method for delineating the protection red line of eutrophic lakes based on pollution reduction is provided. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiment.

[0086] The method described in this invention uses Dianchi Lake as a case lake for the application of the technology.

[0087] First, the land around Dianchi Lake is classified using a lake shoreline land classification system;

[0088] Secondly, based on the water level records of Dianchi Lake, remote sensing images from the ZY-3 satellite with a resolution of 2.0m were loaded; an ArcGIS project file Example.mxd was created, the images were loaded, and the Dianchi Lake L_lower.shp data, i.e., the highest water level line data of Dianchi Lake, was drawn. The total length of the line was 141km. A 2km buffer was established based on the highest water level line to obtain the strip data L_buffer.

[0089] Next, based on the digital elevation data of Dianchi Lake, ArcGIS software was used to analyze flow direction, depression filling, flow rate, river network, and catchment area to obtain the areal data P_watershed, which includes 518 catchment areas. Using the calculation formulas in Table 2 and the data in Tables 3, 4, and 5, the pollution load generation and reduction capacity within each catchment area were calculated. Attributes were assigned to each catchment area, resulting in 165 pollution-generating units, 353 reduction units, and 0 balancing units. Table 3 shows the reference values ​​for the measured runoff pollution index of construction land in the Dianchi Lake basin; Table 4 shows the loss coefficient of fertilizer application (pure) in farmland in the Dianchi Lake basin; and Table 5 shows the pollutant absorption coefficient of ecological land use in the basin (unit: g / m³). 2 *d).

[0090] Table 3 Reference values ​​of measured runoff pollution index from construction land in Dianchi Lake Basin

[0091]

[0092] Table 4. Loss Coefficient of Chemical Fertilizer Application (Pure) in Farmland of Dianchi Lake Basin

[0093]

[0094] Table 5 Pollutant absorption coefficients for ecological land use in the watershed (unit: g / m³) 2 *d)

[0095]

[0096] Finally, using ArcGIS software analysis tools, nearest neighbor analysis was performed on all reduction units, and 251 units were selected for inclusion. Combined with the images, the upper boundary was extracted to obtain the linear data L_upper. Subsequently, the shoreline use type dataset of the areal features and the lake shore protection red line dataset of the linear features were obtained by projection, thus completing the extraction.

[0097] Therefore, this invention can accurately divide the research units based on the land type, elevation distribution and water catchment characteristics around Dianchi Lake, and delineate the lake protection red line based on the dominant attributes of the divided research units.

[0098] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for delineating protection red lines for eutrophic lakes based on pollution reduction, characterized in that, include: Based on the concept of "source-sink", a land use classification system for lake shores based on pollution reduction is constructed; Based on high-resolution remote sensing image data of the lake and its surrounding areas and the aforementioned land use classification system, a search area for identifying land use types along the lake shore is created. Based on the elevation characteristics within the buffer zone, a catchment area is generated, and the pollution load generation and reduction capacity of each catchment area are calculated based on the land use classification system to determine the dominant attribute of the unit. Based on the aforementioned properties, the continuous cut-off unit line border is obtained, and the lakeside protection red line boundary is extracted. The creation of the lake shoreline using type identification search area includes: The software loads linear lake boundary data and uses it as the lower boundary of the lake shore protection red line, and creates a buffer zone outward based on the highest water level line; The dominant attributes include: pollution-generating units, balancing units, and reduction units; the criteria for determining the three dominant attributes are as follows: Pollution-generating unit: Pollution load generation within the catchment area > pollution load reduction capacity; Balance unit: Pollution load generation within the catchment area = pollution load reduction capacity; Reduction unit: Pollution load generation in the catchment area < pollution load reduction capacity.

2. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 1, characterized in that: The land use classification system includes The land along the lake is divided into ecological, residential, and productive types. The ecological type includes mountain, wetland, and estuary types; the residential type includes rural and urban types; and the productive type includes arable land and construction land types.

3. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 2, characterized in that: The concept of "source-sink" includes: The sources of nitrogen and phosphorus pollutants in water bodies are called "sources". In contrast to "sources", "sinks" refer to some regions or ecosystem types that can absorb nitrogen and phosphorus pollutants. The living and productive types in the land classification of the lake shore are regarded as the "sources" of lake eutrophication, and the ecotypes in the land classification of the lake shore are regarded as the "sinks" of lake eutrophication.

4. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 3, characterized in that: The high-resolution remote sensing image data and land use classification system include: Based on the lake's water level records, high-resolution remote sensing image data corresponding to the period of highest water level in a year are selected. The high-resolution remote sensing images are loaded using software, and the highest water level line of the lake and surrounding land use data are obtained based on the remote sensing images.

5. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 4, characterized in that: The generated catchment area includes: Based on digital elevation data of the lake and its surrounding area, software analysis tools are used to analyze flow direction, depression filling, flow rate, river network, and catchment area, thereby creating a watershed area with isometric features.

6. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 5, characterized in that: The calculation of pollution load generation and reduction capacity for each catchment area includes: Calculate the pollution load generated by land use types of residential or industrial use along the lake shore, and calculate the pollution load reduction by land use types of ecological use along the lake shore.

7. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 6, characterized in that: The calculation of pollution load generation and reduction capacity includes: The method for calculating the pollution load generated by urban and rural residential activities is as follows: combining the average mass concentration of each pollutant in rainfall-runoff events obtained from rainfall-runoff monitoring, the formula is expressed as: L=0.001×EMC×R×A built ×P1 Where L is the pollution load generated by urban and rural land use, kg; EMC is the average concentration per rainfall, mg / L, based on field sampling; R is the annual runoff coefficient; P1 is the multi-year average rainfall, mm; A built The area of ​​construction land within the catchment area, in km² 2 ; The method for calculating the pollution load generated by farmland production is as follows: Based on the principle of conservation of mass, the surplus or deficit of the average annual nitrogen and phosphorus nutrient load of farmland is quantitatively described and used as the farmland pollution source load in the model. The formula is expressed as follows: P2=Input×A crop ×r Wherein, P2 represents the pollution load generated by cultivated land use, in kg; Input represents the annual net fertilizer application per unit land area, in t / km². 2 A crop The area is expressed as cultivated land within the catchment area, in km². 2 ; r This is expressed as the churn coefficient; The calculation method for the reduction of pollution load in wetland ecosystems is as follows: The calculation is based on empirical values ​​of pollution load from wetland technical specifications and wetland monitoring data, expressed by the following formula: W=A wet x x ×365*0.001 x =(mi-mo) / d * Wherein, W represents the annual absorption capacity of wetland-type pollution load within the catchment area, in kg; x Expressed as pollutant absorption capacity, g / m 2 ·d; * represents the wetland monitoring formula, mi represents the water quality at the wetland inlet, mo represents the water quality at the lake outlet, and A wet Indicates the area of ​​arable land within the catchment area, in km². 2 d represents the number of days; The calculation method for the reduction of ecological pollution load in forest land is as follows: referring to the reduction parameters of similar typical forest land in China, the formula is expressed as: F=A forest × u ×365*0.001 Wherein, F: annual absorption capacity of forest-type pollution load within the catchment area, kg; u: pollutant absorption capacity, g / m³ 2 ·d, A forest Area of ​​cultivated land within the catchment area, km² 2 .

8. The method for delineating the protection red line of eutrophic lakes based on pollution reduction as described in claim 7, characterized in that: The extraction of the lakeside protection boundary includes: All reduction units were extracted, and nearest neighbor analysis was performed using software analysis tools to extract the nearest reduction unit along the lake. The upper boundary of the lake protection red line was obtained by drawing a continuous line based on its outer boundary. The upper boundary was then interpreted in conjunction with high-resolution imagery and adjusted according to the actual situation around the lake. Finally, the upper and lower boundaries were combined to form the lake shore protection red line.

Images