A quantitative assessment method for the carbon sink effect of flood control measures in the lower reaches of the Yellow River

Abstract

This application provides a quantitative assessment method for the carbon sink effect of flood control measures in the lower reaches of the Yellow River. It relates to the field of flood control technology and fully considers the core characteristics of the lower Yellow River, including siltation, frequent floods, and a complex ecological environment. It specifically covers typical governance projects such as dike reinforcement, river regulation, Yellow River irrigation, and silt-backed dike reinforcement. The carbon sink effect is subdivided into three core scenarios: greening and carbon sequestration, sedimentary carbon storage, and flood control and emission reduction. This fills the gap in the applicability of general carbon sink methodologies in the field of watershed flood control. The methodology explicitly excludes non-core carbon sink increases from crops, forests, grasslands, flowers, and fruits, focusing on key carbon pools such as trees, shrubs, and soil organic carbon. It also specifically designs accounting logic to address special issues such as organic carbon oxidation during sediment transport and methane emissions caused by flooding, ensuring that the assessment results highly match the actual carbon sink contribution of the lower Yellow River governance and avoiding accounting biases caused by applying general methodologies.

Description

Technical Field

[0001] This application relates to the field of flood control technology, and more specifically, to a method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River. Background Technology

[0002] Flood control is a public welfare activity aimed at ensuring the ecological security of the lower reaches of the Yellow River and improving the ecological environment without the purpose of profit. It has important social and ecological benefits such as flood control and security, sediment regulation, fixing and storing carbon dioxide in the atmosphere, and improving regional productivity. However, when carrying out control activities, a large amount of funds need to be invested in engineering construction and maintenance, which is costly and not financially attractive.

[0003] Carbon sequestration in flood control refers to the process or capacity to generate carbon sequestration after projects such as dike reinforcement, river regulation, Yellow River irrigation, and siltation and backfilling are carried out to address issues such as siltation, flood threats, water shortages, and ecological degradation in the lower reaches of the Yellow River. This includes increasing green coverage and carbon sequestration, carbon sequestration through sedimentation, and flood control and emission reduction.

[0004] By utilizing the quantitative assessment of the carbon sink effect, the carbon sink data during flood control can be made more accurate, so that accurate data support can be obtained for subsequent flood control efforts, thereby improving the overall efficiency of flood control.

[0005] To overcome the above-mentioned defects, the prior art (Chinese patent with announcement number CN117789045B and announcement date of 2024-06-25) is a carbon sink monitoring method, system and device for constructing a scientific carbon sink model, which relates to the field of carbon sink monitoring technology, including S1, forest land monitoring target selection, S2, block data collection, S3, carbon storage calculation within the block, S4, forest land data acquisition, S5, carbon sink measurement and S6, carbon sink statistics. The monitoring method of this invention can meticulously count the carbon sequestration of various types of vegetation, such as arbor forests, bamboo forests, shrub forests, sparse forests, newly planted forests, and thickets, in different months based on the soil quality, altitude, and monthly climate and rainfall information of the forest land. By adding comparison items and calculating the average value, the data error caused by insufficient data can be reduced, and the accuracy of carbon sequestration monitoring can be improved. Since the monitoring data of trees is large, the difficulty of collecting tree data can be greatly simplified by using drones equipped with high-definition 3D rangefinders to measure tree data. Prior art 2 (Chinese patent publication number CN121089800A, publication date 2025-12-09) discloses a wetland carbon sink monitoring system and a carbon sink assessment method. The wetland carbon sink monitoring system is based on open-circuit / closed-circuit eddy design. The detection equipment of the wetland carbon sink monitoring system includes a carbon dioxide analyzer, a three-dimensional ultrasonic anemometer, a methane analyzer, a sunlight-induced chlorophyll fluorescence observation device, and a micrometeorological monitoring device. A carbon sink model is constructed based on the wetland carbon sink monitoring system. Compared with the prior art, the present invention monitors major greenhouse gases in real time, obtains high-frequency continuous carbon budget data of the atmosphere-vegetation interface and the atmosphere-water interface, reveals the temporal variation characteristics of carbon sinks in wetland and aquatic ecosystems, and constructs a carbon sink model by combining micrometeorological monitoring and environmental data to clarify the carbon sink pattern and influencing factors of Hongze Lake wetland and estimate the carbon sink potential of Hongze Lake wetland.

[0006] The aforementioned institutions collected various carbon sink data by using carbon sink models, but when carrying out flood control and management of the Yellow River, they did not fully cover the multi-dimensional carbon sink effects of flood control and management in the lower reaches of the Yellow River; some scenarios were not included in the accounting, resulting in an assessment gap. Summary of the Invention

[0007] This application provides a quantitative assessment method for the carbon sink effect of flood control measures in the lower reaches of the Yellow River. This method can accurately quantify the diverse carbon sink effects of flood control projects in the lower reaches of the Yellow River, covering three core scenarios: greening and carbon sequestration, carbon sequestration, and flood control and emission reduction. It avoids the adaptation bias of general methodologies. A logically closed-loop accounting system is established, ensuring the scientific validity, accuracy, and traceability of carbon sink data through dedicated formulas, clear parameters, and hierarchical carbon layer division. It connects with the national voluntary emission reduction trading mechanism, providing standardized methodological support for projects to participate in the carbon market in compliance with regulations. Simultaneously, it reflects the ecological value and carbon sink contribution of flood control measures, contributing to the coordinated advancement of dual carbon goals and watershed ecological protection.

[0008] Firstly, this application provides a method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River, the method comprising the following steps: S1. Define the scope and boundaries of the project. The scope and boundaries of the project refer to the geographical area of ​​the flood control project activities implemented by the project participants who own the land ownership or use rights. A project scenario can be carried out on several different plots of land, but each plot of land should have specific geographical boundaries. S2. Delineate the project carbon layer. The project carbon layer refers to the set of spatial units with relative internal homogeneity and significant inter-layer differences within the boundary of the Yellow River downstream flood control carbon sink project. This is determined based on key driving factors that significantly affect the spatial distribution and dynamic changes of carbon storage, such as land use, vegetation cover type, control measures, slope position, and slope gradient. It is achieved through a multi-level system combined with remote sensing, GIS, and field surveys. After delineation, the variability of carbon storage within the layer needs to be verified through one-way ANOVA to ensure that the carbon sink accounting and verification requirements are met. S3. Determine the carbon pool and emission sources. Determining the carbon pool and emission sources is a fundamental step in the accounting of the Yellow River downstream flood control carbon sink project. It refers to clarifying the types of carbon pools, greenhouse gas types and corresponding emission sources to be included in the accounting within the project boundary based on principles such as the proportion of carbon pool removal and the correlation of emission sources. S4. Collect and monitor accounting parameters. The collection and monitoring of accounting parameters is a key link in the accounting of carbon sink projects for flood control and management in the lower reaches of the Yellow River. It refers to the systematic collection, measurement or acquisition of various parameters required for carbon sink accounting according to the project design and implementation stages, to ensure that the data is true and reliable to support accurate accounting. S5. Calculate the carbon sink of the project. The calculation of the carbon sink of the project is the core link of the Yellow River downstream flood control carbon sink project. It refers to the process of calculating the greening and carbon sink increase, the carbon sequestration, and the flood control emission reduction through specified formulas based on the clear project boundary, carbon layer division, carbon pool and emission source and related accounting parameters, and finally summing them to obtain the total carbon sink of the project. S6. Conduct review and verification. The review and verification is a necessary step for the carbon sink project for flood control in the lower reaches of the Yellow River. It refers to the verification by a third-party verification agency through document review, on-site audit and feedback procedures to verify the authenticity, accuracy and confidentiality of the project, and to ensure that the carbon sink data and project compliance meet the requirements.

[0009] In this embodiment, the method for S1 to define the project scope and boundaries includes: S1-1. Use the Global Positioning System, BeiDou Navigation Satellite System or other satellite navigation systems to perform single-point positioning or differential technology to directly determine the coordinates of the inflection points of the project plot boundary, with a positioning error not exceeding ±10m; S1-2. Using high-resolution geospatial data, vegetation distribution maps, etc., the boundary coordinates of the project site can be directly read with the assistance of a geographic information system.

[0010] S1-3. Use topographic maps with a scale of not less than 1:10000 for on-site drawing, and combine them with GPS or other satellite positioning systems for accuracy control.

[0011] In this embodiment, the S2 method for dividing the carbon layer of the project includes: S2-1, Division Principles; S2-2, Basic Data Collection and Preparation; S2-3, Division steps; S2-4. Homogeneity verification and optimization.

[0012] In this embodiment, when determining the carbon pool and emission sources in S3, the baseline scenario only includes the soil organic carbon pool, while the project scenario includes aboveground biomass, underground biomass, and the soil organic carbon pool; it also includes CO2 emissions from soil organic carbon mineralization and decomposition under the baseline scenario, CH4 emissions from possible anaerobic decomposition of soil organic carbon, and CO2 emissions from mobile source fossil fuel combustion under the project scenario.

[0013] In this embodiment, the S4 collection and monitoring of accounting parameters includes parameter collection during the design phase, parameter monitoring during the implementation phase, and data management.

[0014] In this embodiment, the parameter collection during the design phase obtains fixed parameters such as vegetation carbon coefficient, biomass model, sediment organic carbon oxidation ratio, and methane emission factor from specified standards, literature, or default values, without requiring on-site monitoring. The parameter monitoring during the implementation phase obtains key dynamic parameters through field measurements and engineering data retrieval, including carbon layer area, flooded land area, soil organic carbon content, soil bulk density, biomass per unit area, sediment deposition, and effective methane emission days. Monitoring must adhere to specified methods, instruments, and quality control requirements. Data management involves establishing a monitoring plan and record-keeping system, and ensuring the authenticity, accuracy, and completeness of parameters through dedicated personnel, mutual inspection and verification, and cross-validation, providing reliable data support for carbon sink accounting.

[0015] In this embodiment, the soil organic carbon content was determined by combustion oxidation-non-dispersive infrared method specified in HJ695 or potassium dichromate oxidation-spectrophotometric method specified in HJ615. Soil bulk density was determined by the method specified in NY / T1121.4. Biomass per unit area was calculated by combining measured tree height, diameter at breast height or basal diameter data with the biomass model in Appendix A.

[0016] In this embodiment, the carbon sequestration amount of the S5 accounting project includes: S5-1. Calculate the total carbon sequestration using the formula; S5-2, Calculated by combining the changes in vegetation carbon pool and soil carbon pool storage with the carbon conversion coefficient; S5-3, calculated using siltation volume, organic carbon content of silted sediment, oxidation ratio, and carbon conversion coefficient; S5-4. Calculate by subtracting the carbon emissions from fossil fuels used in the construction of the project from the sum of direct and indirect emission reductions.

[0017] In this embodiment, step S6, which involves conducting an approval and verification process, includes: S6-1. Verify the applicable conditions of the project: verify whether the project complies with laws, regulations and industry policies, whether the land plot is qualified, and whether the land ownership is clear and has relevant supporting documents; S6-2. Verify the project start time: Verify the authenticity of the project start time by comparing supporting materials such as satellite remote sensing images, site visits and work designs, and construction contracts; S6-3. Verify project boundaries: Randomly select the measured inflection point coordinates of plots to verify the positioning and area errors; check whether the actual boundaries are consistent with the design boundaries and confirm whether the land use type has changed. S6-4. Verify the carbon sequestration calculation of the project: verify the consistency of the calculation and monitoring methods, the scientific nature of the selection of sample plots and sampling points, the rationality of the parameter selection, and the accuracy of the calculation results to ensure compliance with the principle of conservatism.

[0018] In this embodiment, the calculation scope of the carbon sink of the project excludes the carbon sink increase of crop vegetation, the carbon sink increase of forest and grassland measures such as flowers, leaves, fruits and herbaceous plants. Under the baseline scenario, only soil organic carbon is included, while under the project scenario, aboveground biomass, underground biomass and soil organic carbon are included.

[0019] The technical solutions provided by the embodiments disclosed in this application have the following beneficial effects: This study fully considers the core characteristics of the lower Yellow River, including siltation, frequent floods, and a complex ecological environment. It specifically covers typical governance projects such as dike reinforcement, river regulation, Yellow River irrigation, and silt-backed dike reinforcement. The carbon sink effect is subdivided into three core scenarios: greening and carbon sequestration, sedimentary carbon storage, and flood control and emission reduction. This fills the gap in the application of general carbon sink methodologies in the field of watershed flood control. The methodology explicitly excludes non-core carbon sink increases such as crops, forests, grasslands, flowers, and fruits, focusing on key carbon pools such as trees, shrubs, and soil organic carbon. At the same time, it specifically designs accounting logic for special issues such as organic carbon oxidation during sediment transport and methane emissions caused by flooding, ensuring that the assessment results are highly consistent with the actual carbon sink contribution of the lower Yellow River governance and avoiding accounting bias caused by the application of general methodologies.

[0020] The assessment methodology constructs a comprehensive accounting framework: "Total carbon sink = Increased carbon sink due to vegetation cover + Sedimentary carbon sequestration + Flood control emission reduction." This framework encompasses both the incremental accounting of vegetation and soil carbon pools and the carbon sequestration effect brought about by sedimentation. More innovatively, it includes the methane emission reduction from flood control measures, achieving full-dimensional coverage of carbon sink enhancement, carbon sequestration, and carbon emission reduction. In terms of accounting details, specific formulas are designed for different carbon sink types, clarifying the definitions, units, and acquisition methods of each parameter. Increased carbon sink due to vegetation cover distinguishes between changes in vegetation and soil carbon pools. Sedimentary carbon sequestration incorporates parameters such as sediment organic carbon content and oxidation ratio. Flood control emission reduction deducts fossil fuel carbon emissions from project construction. This forms a logically closed-loop, parameter-clear, and calculation-standardized accounting system, ensuring the scientific validity and accuracy of the assessment results.

[0021] The methodology outlines a core process for determining project boundaries, delineating carbon layers, identifying carbon pools and emission sources, collecting monitoring parameters, calculating carbon sinks, and conducting verification and validation. Each step clearly defines specific requirements and implementation methods. Project boundaries can be determined through various methods such as GPS / BDS positioning, GIS-assisted reading, or topographic mapping. Carbon layer delineation employs a multi-level system with primary, secondary, and optional tertiary levels, validated for homogeneity. The verification and validation process clarifies the verification dimensions and standards for third-party organizations. Furthermore, the methodology provides practical tools such as the biomass model and parameters in Appendix A, the carbon layer delineation method in Appendix B, and the field sampling method in Appendix C. This not only meets the professional requirements of carbon sink assessment but also reduces the difficulty of practical operation, enabling project owners, monitoring agencies, and verification agencies to conduct their work according to regulations, demonstrating strong operability.

[0022] Therefore, this application enables the quantitative assessment of the carbon sink effect of flood control measures. First, the project scope is clearly defined by defining the basic project, and then the carbon layer is divided and its homogeneity is verified. Next, the carbon pool and emission sources are determined, and the accounting scope is clarified. Carbon sink is calculated through parameter collection and monitoring. Finally, the entire process is completed through review and verification.

[0023] In summary, the technical solution adopted in this application can realize the quantitative assessment of the carbon sink effect of flood control measures. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this embodiment of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1This is a flowchart of the basic steps of a quantitative assessment method for the carbon sink effect of flood control measures in the lower reaches of the Yellow River, provided in this application. Figure 2 This is based on the S2 step flowchart provided in this application; Figure 3 This is based on the S5 step flowchart provided in this application; Figure 4 The carbon pool is selected or not selected based on the project boundaries provided in this application; Figure 5 This is based on the emission sources and types of greenhouse gases included within the project boundary provided in this application. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] This application provides a method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River. Its core is to achieve accurate quantification of the diverse carbon sink effects of flood control projects in the lower reaches of the Yellow River through a standardized design of the entire process, which includes clearly defining boundaries and carbon pools, scientific hierarchical accounting, standardized data monitoring, and strict review and verification. This method covers three core scenarios: greening and carbon sink enhancement, carbon sequestration, and flood control and emission reduction, thus avoiding the adaptation bias of general methodologies.

[0028] Example 1: To better understand the above technical solution, the following will provide a detailed description of the technical solution in conjunction with the accompanying drawings and specific implementation methods. (Refer to...) Figure 1 As shown in the figure, this is an exemplary flowchart of a method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River according to this embodiment of the application. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River includes the following steps: S1. Define the scope and boundaries of the project. The scope and boundaries of the project refer to the geographical area of ​​the flood control project activities implemented by the project participants who own the land ownership or use rights. A project scenario can be carried out on several different plots of land, but each plot of land should have specific geographical boundaries. S2. Delineate the project carbon layer. The project carbon layer refers to the set of spatial units with relative internal homogeneity and significant inter-layer differences within the boundary of the Yellow River downstream flood control carbon sink project. This is determined based on key driving factors that significantly affect the spatial distribution and dynamic changes of carbon storage, such as land use, vegetation cover type, control measures, slope position, and slope gradient. It is achieved through a multi-level system combined with remote sensing, GIS, and field surveys. After delineation, the variability of carbon storage within the layer needs to be verified through one-way ANOVA to ensure that the carbon sink accounting and verification requirements are met. S3. Determine the carbon pool and emission sources. Determining the carbon pool and emission sources is a fundamental step in the accounting of the Yellow River downstream flood control carbon sink project. It refers to clarifying the types of carbon pools, greenhouse gas types and corresponding emission sources to be included in the accounting within the project boundary based on principles such as the proportion of carbon pool removal and the correlation of emission sources. S4. Collect and monitor accounting parameters. The collection and monitoring of accounting parameters is a key link in the accounting of carbon sink projects for flood control and management in the lower reaches of the Yellow River. It refers to the systematic collection, measurement or acquisition of various parameters required for carbon sink accounting according to the project design and implementation stages, to ensure that the data is true and reliable to support accurate accounting. S5. Calculate the carbon sink of the project. The calculation of the carbon sink of the project is the core link of the Yellow River downstream flood control carbon sink project. It refers to the process of calculating the greening and carbon sink increase, the carbon sequestration, and the flood control emission reduction through specified formulas based on the clear project boundary, carbon layer division, carbon pool and emission source and related accounting parameters, and finally summing them to obtain the total carbon sink of the project. S6. Conduct review and verification. The review and verification is a necessary step for the carbon sink project for flood control in the lower reaches of the Yellow River. It refers to the verification by a third-party verification agency through document review, on-site audit and feedback procedures to verify the authenticity, accuracy and confidentiality of the project, and to ensure that the carbon sink data and project compliance meet the requirements.

[0029] It should be noted that S1 defines the project scope and boundaries using the following methods: S1-1. Use the Global Positioning System, BeiDou Navigation Satellite System or other satellite navigation systems to perform single-point positioning or differential technology to directly determine the coordinates of the inflection points of the project plot boundary, with a positioning error not exceeding ±10 m; S1-2. Using high-resolution geospatial data, vegetation distribution maps, etc., the boundary coordinates of the project site can be directly read with the assistance of a geographic information system.

[0030] S1-3. Use topographic maps with a scale of not less than 1:10000 for on-site drawing, and combine them with GPS or other satellite positioning systems for accuracy control.

[0031] It should be noted that the S2 method for dividing the carbon layers of a project includes: S2-1. Classification Principles: Within the same carbon layer, the key environmental factors affecting carbon storage, current and historical land use / vegetation cover, and remediation measures of the plots should be highly similar to ensure that the spatial variability of the total carbon storage in that layer is minimized. Priority should be given to factors that play a decisive role in the spatial differentiation of carbon storage in the lower reaches of the Yellow River and are easy to obtain / measure. A multi-level classification system should be adopted, gradually refining from macro to micro to ensure that the classification of each layer has clear basis and operability. The basis for classification should be objectively obtained through remote sensing, GIS, field surveys, etc., and the classification results should be able to verify the homogeneity within the layer through statistical testing. S2-2, Basic Data Collection and Preparation; Before carbon layer partitioning, the following basic data collection and preparation work should be carried out: High-resolution land use map: Based on the latest remote sensing image interpretation and combined with field verification, detailed land use patches are drawn.

[0032] The classification system should include: arbor forests, shrub forests, natural grasslands, artificial grasslands, farmland, bare / degraded land, water bodies, and construction land.

[0033] Distribution map of governance measures: Record in detail and spatialize the core governance measures implemented in the project area. Among them, engineering measures should indicate the year of construction, type of coverage, etc., and vegetation measures should indicate the tree species, age of forest, and whether tending is required, etc.

[0034] Topographic data: Acquire digital elevation data for slope grading and slope position classification with a resolution of ≤5 m.

[0035] Auxiliary data on vegetation characteristics: Dominant species, average height, canopy coverage, diameter at breast height (DBH), base diameter, forest / grass age, etc., were investigated in field sample plots. Remote sensing vegetation indices were used to help determine the growth status and spatial coverage, which showed differences.

[0036] Soil baseline data: Soil type map, soil sand, silt, and clay content range map or regional typical values.

[0037] S2-3. Delineation steps: Delineate the first-level carbon layer, and spatially overlay the land use map and the governance measure map based on the main land use / vegetation cover types and governance measure categories.

[0038] To divide the carbon layer into two levels, based on slope position and slope grade, slope position and slope maps are overlaid on each patch of the first-level carbon layer for further subdivision, prioritizing slope position factors. When there are large differences in slope at the same slope position, it is necessary to distinguish between them.

[0039] Divide the carbon layer into three levels (only when data supports this and it can significantly improve the homogeneity within the layer). Further subdivision is performed when the carbon reserves within the second-level carbon layer may still vary significantly due to the following factors: Soil texture / thickness: If there is detailed soil data for the project area, and the soil texture or thickness varies significantly within the same secondary layer, then this subdivision applies.

[0040] Differences in vegetation growth: If, through remote sensing indices (or field surveys), it is found that there are significant spatial differences in vegetation growth under the same Level 1 and Level 2 conditions, it can be further subdivided according to slope aspect, vegetation cover / canopy density level, and measured growth index level.

[0041] It should be noted that when determining the carbon pool and emission sources in S3, the baseline scenario only includes the soil organic carbon pool, while the project scenario includes aboveground biomass, underground biomass, and the soil organic carbon pool; it also includes CO2 emissions from soil organic carbon mineralization and decomposition under the baseline scenario, CH4 emissions from possible anaerobic decomposition of soil organic carbon, and CO2 emissions from mobile source fossil fuel combustion under the project scenario.

[0042] Verify whether the variability of carbon reserves within each carbon layer after partitioning is sufficiently small, significantly smaller than the interlayer differences: Within each final determined carbon layer, a certain number of verification plots are randomly distributed; Within each plot, vegetation carbon storage and soil organic carbon storage shall be measured in accordance with the provisions of this document; One-way ANOVA was conducted to compare whether there were significant differences in the average total carbon storage of sample plots among different carbon layers.

[0043] If the verification reveals excessive variability within certain carbon layers, the classification criteria need to be re-examined. This includes checking for any omissions of key influencing factors, verifying the reasonableness of the threshold settings for primary or secondary classification, considering whether to add new classification levels, or splitting the current layer into smaller ones. Based on the verification results, the classification scheme should be adjusted, GIS overlay and mapping should be redone, and sampling verification should be repeated until the homogeneity requirements are met.

[0044] It should be noted that the S4 collection and monitoring of accounting parameters includes parameter collection during the design phase, parameter monitoring during the implementation phase, and data management.

[0045] It should be noted that the parameter collection in the design phase obtains fixed parameters such as vegetation carbon coefficient, biomass model, sediment organic carbon oxidation ratio, and methane emission factor from specified standards, literature, or default values, without the need for on-site monitoring. The parameter monitoring in the implementation phase obtains key dynamic parameters through field measurements and engineering data retrieval, including carbon layer area, flooded land area, soil organic carbon content, soil bulk density, biomass per unit area, sediment deposition, and effective methane emission days. Monitoring must follow specified methods, instruments, and quality control requirements. Data management: Establish a monitoring plan and ledger system, and ensure the authenticity, accuracy, and completeness of parameters through measures such as dedicated personnel, mutual inspection and verification, and cross-validation, providing reliable data support for carbon sink accounting.

[0046] It should be noted that the soil organic carbon content was determined using the combustion oxidation-non-dispersive infrared method specified in HJ 695 or the potassium dichromate oxidation-spectrophotometric method specified in HJ 615, the soil bulk density was determined using the method specified in NY / T 1121.4, and the biomass per unit area was calculated by combining the measured tree height, diameter at breast height or basal diameter data with the biomass model in Appendix A.

[0047] It should be noted that the carbon sink of the project calculated in S5 includes: S5-1, calculating the total carbon sink using a formula; S5-2, calculating the carbon sink by combining the changes in vegetation carbon pool and soil carbon pool with the carbon conversion coefficient; S5-3, calculating the carbon sink by combining the amount of sediment deposition, the organic carbon content of sediment, the oxidation ratio, and the carbon conversion coefficient; and S5-4, calculating the carbon sink by subtracting the carbon emissions from fossil fuels used in the project construction from the sum of direct and indirect emission reductions.

[0048] It should be noted that the relevant terms and definitions mentioned in this application are as follows: Increase green coverage and carbon sequestration: Implementing measures such as planting trees and grasses to increase the biomass of surface vegetation, and inputting organic matter into the surface through forest and grass litter and root exudates, thereby increasing the organic carbon content of the topsoil and increasing the increase of soil carbon sequestration.

[0049] Carbon sequestration: Implement measures such as mechanical siltation and dike reinforcement to pump and deposit river sediment, thereby reducing the CO2 released by organic carbon mineralization during sediment transport.

[0050] Flood control and emission reduction: Implement measures such as dike reinforcement and river regulation to prevent large amounts of methane emissions caused by floods breaching dams and submerging soil and vegetation.

[0051] Baseline scenario: A scenario that represents the vegetation and soil carbon sequestration within the project boundary when no remediation activities are implemented. Land use and management practices remain unchanged in the baseline scenario.

[0052] Project Scenario: The scenario of the carbon sink situation of the accounting object during carbon sink accounting.

[0053] Carbon layer: Within the project boundary, a set of spatial units with relative internal homogeneity and significant interlayer differences are delineated using a scientific stratification method based on key driving factors that significantly affect the spatial distribution pattern and dynamic changes of carbon reserves.

[0054] Carbon sequestration calculation method: (1) In the formula: C p —Project carbon sink, t CO2e (tons of carbon dioxide equivalent). C VS —Project-related increase in green carbon dioxide emissions, t CO2e; C S —Project carbon sequestration amount, t CO2e; C FR —Project flood control and emission reduction, t CO2e; L K —Project leakage: According to the applicable conditions of this document, the project activities will not cause a change in the land use patterns that may be carried out in the future within the project boundary. Therefore, under this document, there is no potential leakage of flood control activities, i.e., LK=0.

[0055] Increase in green exchange rate: (2) (3) (4) (5) (6) In the formula: C VS —Project-related increase in green carbon dioxide emissions, t CO2e; ∆ vc —Changes in carbon storage in the vegetation carbon pool of the project, t C; ∆ sc —Changes in soil carbon storage in the project, t C; i — Project carbon layer, i = 1, 2, 3, ..., n-1, n, dimensionless; V cp,i —In the project scenario, the vegetation carbon storage per unit area of ​​the i-th carbon layer is t C / hm. 2 ; V co,i — Under the baseline scenario, the vegetation carbon storage per unit area of ​​the i-th carbon layer is t C / hm. 2 ; A i—The area of ​​the i-th carbon layer in the project, hm 2 ; S cp,i —In the project scenario, the soil organic carbon density t C / hm² of the i-th carbon layer. 2 ; S co,i —Soil organic carbon density of the i-th carbon layer under the baseline scenario, t C / hm 2 ; SOC i —The soil organic carbon content of the i-th carbon layer in the project is divided into baseline scenario (SOCo) ,i ) and project scenarios (SOCp) ,i ), g / kg; BD i —The soil bulk density of the i-th carbon layer in the project is divided into baseline scenario (BDo). ,i ) and project scenarios (BDp) ,i ), g / cm 3 ; D—Soil layer thickness, cm; B i —Biomass per unit area of ​​the i-th carbon layer in the project, t / hm 2 ; f c,i —The vegetation carbon content coefficient of the i-th carbon layer of the project, dimensionless.

[0056] Deposited carbon sequestration: (7) In the formula: C S —Project carbon sequestration amount, t CO2e; S M — Project sediment deposition volume, tons.

[0057] SOC M —Organic carbon content of the silt deposited in the project, g / kg; P se —The proportion of soil organic carbon oxidized during sediment transport, dimensionless.

[0058] Flood control and emission reduction: (8) (9) (10) In the formula: C FR —Project flood control and emission reduction, t CO2e; F DR—Direct emission reduction from flood control by the project, t CO2e; A w —The area of ​​land submerged by floodwaters, hm2; t e —The number of days of effective methane emissions during a flood event, in days; 25 — Global warming potential of methane, dimensionless; EF m —Methane emission factor, g / (m 2 d); E f —Carbon emissions from the combustion of fossil fuels by vehicles and machinery during project construction, t CO2e; M a —Diesel consumption, tons; 42.652 — Lower heating value of diesel oil, GJ / t; 0.0202 — Carbon content per unit of calorific value, t C / GJ; F IR —The project's indirect emission reduction from flood control is calculated by referring to the type and quantity of fossil fuels used in vehicles and machinery required for post-flood reconstruction, as well as the CO2 coefficient generated by their combustion.

[0059] It should be noted that the S6 review and verification process includes: S6-1. Verify the applicable conditions of the project: verify whether the project complies with laws, regulations and industry policies, whether the land plot is qualified, and whether the land ownership is clear and has relevant supporting documents; S6-2. Verify the project start time: Verify the authenticity of the project start time by comparing supporting materials such as satellite remote sensing images, site visits and work designs, and construction contracts; S6-3. Verify project boundaries: Randomly select the measured inflection point coordinates of plots to verify the positioning and area errors; check whether the actual boundaries are consistent with the design boundaries and confirm whether the land use type has changed. S6-4. Verify the carbon sequestration calculation of the project: verify the consistency of the calculation and monitoring methods, the scientific nature of the selection of sample plots and sampling points, the rationality of the parameter selection, and the accuracy of the calculation results to ensure compliance with the principle of conservatism.

[0060] It should be noted that the calculation scope of the carbon sink of the project excludes the carbon sink increase of crop vegetation, the carbon sink increase of forest and grassland measures such as flowers, leaves, fruits and herbaceous plants. Under the baseline scenario, only soil organic carbon is included, while under the project scenario, aboveground biomass, underground biomass and soil organic carbon are included.

[0061] In summary, the technical solution adopted in this application can fully combine the core characteristics of the lower Yellow River, such as siltation, frequent floods, and complex ecological environment. It specifically covers typical governance projects such as dike reinforcement, river regulation, Yellow River irrigation and silt-backed dike reinforcement. The carbon sink effect is subdivided into three core scenarios: greening and carbon sequestration, sedimentary carbon storage, and flood control and emission reduction. This fills the gap in the application of general carbon sink methodologies in the field of watershed flood control. The methodology explicitly excludes non-core carbon sink increases such as crops, forests, grasses, flowers and fruits, focusing on key carbon pools such as trees, shrubs and soil organic carbon. At the same time, it specifically designs accounting logic for special issues such as organic carbon oxidation during sediment transport and methane emissions caused by flooding, ensuring that the assessment results are highly consistent with the actual carbon sink contribution of the lower Yellow River governance and avoiding accounting deviations caused by the application of general methodologies.

[0062] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

Claims

1. A method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River, characterized in that, The method for quantitatively assessing the carbon sink effect includes the following steps: S1. Define the scope and boundaries of the project. The scope and boundaries of the project refer to the geographical area of ​​the flood control project activities implemented by the project participants who own the land ownership or use rights. A project scenario can be carried out on several different plots of land, but each plot of land should have specific geographical boundaries. S2. Delineate the project carbon layer. The project carbon layer refers to the set of spatial units with relative internal homogeneity and significant inter-layer differences within the boundary of the Yellow River downstream flood control carbon sink project. This is determined based on key driving factors that significantly affect the spatial distribution and dynamic changes of carbon storage, such as land use, vegetation cover type, control measures, slope position, and slope gradient. It is achieved through a multi-level system combined with remote sensing, GIS, and field surveys. After delineation, the variability of carbon storage within the layer needs to be verified through one-way ANOVA to ensure that the carbon sink accounting and verification requirements are met. S3. Determine the carbon pool and emission sources. Determining the carbon pool and emission sources is a fundamental step in the accounting of the Yellow River downstream flood control carbon sink project. It refers to clarifying the types of carbon pools, greenhouse gas types and corresponding emission sources to be included in the accounting within the project boundary based on principles such as the proportion of carbon pool removal and the correlation of emission sources. S4. Collect and monitor accounting parameters. The collection and monitoring of accounting parameters is a key link in the accounting of carbon sink projects for flood control and management in the lower reaches of the Yellow River. It refers to the systematic collection, measurement or acquisition of various parameters required for carbon sink accounting according to the project design and implementation stages, to ensure that the data is true and reliable to support accurate accounting. S5. Calculate the carbon sink of the project. The calculation of the carbon sink of the project is the core link of the Yellow River downstream flood control carbon sink project. It refers to the process of calculating the greening and carbon sink increase, the carbon sequestration, and the flood control emission reduction through specified formulas based on the clear project boundary, carbon layer division, carbon pool and emission source and related accounting parameters, and finally summing them to obtain the total carbon sink of the project. S6. Conduct review and verification. The review and verification is a necessary step for the carbon sink project for flood control in the lower reaches of the Yellow River. It refers to the verification by a third-party verification agency through document review, on-site audit and feedback procedures to verify the authenticity, accuracy and confidentiality of the project, and to ensure that the carbon sink data and project compliance meet the requirements.

2. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 1, characterized in that, S1 methods for defining project scope and boundaries include: S1-1. Use the Global Positioning System, BeiDou Navigation Satellite System or other satellite navigation systems to perform single-point positioning or differential technology to directly determine the coordinates of the inflection points of the project plot boundary, with a positioning error not exceeding ±10m; S1-2. Using high-resolution geospatial data, vegetation distribution maps, etc., the boundary coordinates of the project site can be directly read with the assistance of a geographic information system. S1-3. Use topographic maps with a scale of not less than 1:10000 for on-site drawing, and combine them with GPS or other satellite positioning systems for accuracy control.

3. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 2, characterized in that, The S2 method for dividing carbon layers in a project includes: S2-1, Division Principles; S2-2, Basic Data Collection and Preparation; S2-3, Division steps; S2-4. Homogeneity verification and optimization.

4. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 3, characterized in that, When determining the carbon pool and emission sources in S3, the baseline scenario only includes the soil organic carbon pool, while the project scenario includes aboveground biomass, underground biomass, and the soil organic carbon pool; it also includes CO2 emissions from soil organic carbon mineralization and decomposition under the baseline scenario, CH4 emissions from possible anaerobic decomposition of soil organic carbon, and CO2 emissions from mobile source fossil fuel combustion under the project scenario.

5. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 4, characterized in that, The S4 collection and monitoring of accounting parameters includes parameter collection during the design phase, parameter monitoring during the implementation phase, and data management.

6. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 5, characterized in that, The design phase parameter collection obtains fixed parameters such as vegetation carbon coefficient, biomass model, sediment organic carbon oxidation ratio, and methane emission factor from specified standards, literature, or default values, without requiring on-site monitoring. The implementation phase parameter monitoring obtains key dynamic parameters through field measurements and engineering data retrieval, including carbon layer area, flood-inundated land area, soil organic carbon content, soil bulk density, biomass per unit area, sediment deposition, and effective methane emission days. Monitoring must follow specified methods, instruments, and quality control requirements. The data management involves establishing a monitoring plan and ledger system, and ensuring the authenticity, accuracy, and completeness of parameters through measures such as designated personnel, mutual inspection and verification, and cross-validation, providing reliable data support for carbon sink accounting.

7. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 6, characterized in that, The soil organic carbon content was determined using the combustion oxidation-non-dispersive infrared method specified in HJ695 or the potassium dichromate oxidation-spectrophotometric method specified in HJ615. Soil bulk density was determined using the method specified in NY / T1121.

4. Biomass per unit area was calculated by combining measured tree height, diameter at breast height (DBH), or basal diameter data with the biomass model in Appendix A.

8. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 7, characterized in that, The carbon sequestration amount of the S5 accounting project includes: S5-1. Calculate the total carbon sequestration using the formula; S5-2, Calculated by combining the changes in vegetation carbon pool and soil carbon pool storage with the carbon conversion coefficient; S5-3, calculated using siltation volume, organic carbon content of silted sediment, oxidation ratio, and carbon conversion coefficient; S5-4. Calculate by subtracting the carbon emissions from fossil fuels used in the construction of the project from the sum of direct and indirect emission reductions.

9. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 8, characterized in that, The S6 review and verification process includes: S6-1. Verify the applicable conditions of the project: verify whether the project complies with laws, regulations and industry policies, whether the land plot is qualified, and whether the land ownership is clear and has relevant supporting documents; S6-2. Verify the project start time: Verify the authenticity of the project start time by comparing supporting materials such as satellite remote sensing images, site visits and work designs, and construction contracts; S6-3. Verify project boundaries: Randomly select the measured inflection point coordinates of plots to verify the positioning and area errors; check whether the actual boundaries are consistent with the design boundaries and confirm whether the land use type has changed. S6-4. Verify the carbon sequestration calculation of the project: verify the consistency of the calculation and monitoring methods, the scientific nature of the selection of sample plots and sampling points, the rationality of the parameter selection, and the accuracy of the calculation results to ensure compliance with the principle of conservatism.

10. The method for quantitatively assessing the carbon sink effect of flood control measures in the lower reaches of the Yellow River as described in claim 9, characterized in that, The scope of carbon sequestration calculation for the aforementioned projects excludes the carbon sequestration from crop vegetation, forestry and grassland measures, flowers, leaves, fruits, and herbaceous plants. Under the baseline scenario, only soil organic carbon is included in the carbon pool selection, while under the project scenario, aboveground biomass, underground biomass, and soil organic carbon are included.

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