Reservoir sand deposition carbon emission accounting method, system, storage medium and equipment

Abstract

The present application discloses a reservoir silt net carbon emission accounting method, system, storage medium and equipment, wherein the reservoir silt net carbon emission accounting method obtains the total carbon dioxide emission equivalent under the non-reservoir construction scenario by calculating the carbon dioxide emission equivalent of river silt under the non-reservoir construction scenario and the carbon dioxide emission equivalent of estuary silt under the non-reservoir construction scenario; obtains the total carbon dioxide emission equivalent under the reservoir construction scenario by calculating the carbon dioxide emission equivalent of the reservoir, the carbon dioxide emission equivalent of river silt after the construction of the reservoir and the carbon dioxide emission equivalent of estuary silt after the construction of the reservoir; and calculates the reservoir silt net carbon emission. The method objectively quantifies the reservoir silt net carbon emission based on the basic parameters of the reservoir, the river and the estuary and the related parameters of carbon migration and transformation after the construction of the reservoir.

Description

Technical Field

[0001] This invention relates to the field of aquatic ecological environment, specifically to a method for calculating the net carbon emissions of reservoir siltation. Background Technology

[0002] Rivers transport large amounts of sediment to the ocean annually. Damming and impounding reservoirs transform river channels into waterways, altering the river's hydrological dynamics. Upstream sediment carries significant amounts of organic matter, which decomposes within the reservoir. Furthermore, the anaerobic environment at the reservoir bottom provides a favorable habitat for methanogenic bacteria. The sediment at the reservoir bottom is a major source of greenhouse gases, producing carbon dioxide (CO2) and methane (CH4), creating a carbon emission hotspot and sparking widespread debate about the "greenness" of hydropower. However, even without reservoir construction, sediment carrying organic carbon still decomposes during river transport and at the river mouth, generating substantial amounts of CO2 and CH4. Therefore, relying solely on reservoir carbon emission observations cannot objectively assess the changes in net carbon emissions from sediment deposition after reservoir construction. Summary of the Invention

[0003] Purpose of the invention: This invention provides a method for calculating the net carbon emissions from reservoir sedimentation. This method objectively quantifies the net carbon emissions from reservoir sedimentation based on the basic parameters of the reservoir, river, and estuary, as well as relevant parameters of carbon migration and transformation, after the reservoir is built.

[0004] Technical solution: This invention discloses a method for calculating the net carbon emissions from reservoir siltation, including the following steps:

[0005] S1. Calculate the total carbon dioxide emission equivalent (GWP) under the scenario without reservoir construction. 1 The specific steps are as follows:

[0006] S11, Based on the hydraulic residence time (WRT) of the river channel Ri Estimating the amount of organic carbon input to the estuary without reservoir construction based on river organic carbon flux (C0).

[0007] Where K OC K is the degradation coefficient of organic carbon in the river channel. OC =0.3829×(WRT) Ri ) -0.45 ;

[0008] S12. Calculate the carbon dioxide emission equivalent of river sedimentation under the scenario without reservoir construction.

[0009]

[0010] Where X RiIt is the CH4 / CO2 carbon emission ratio in the river environment, and K is the CH4-CO2-eq conversion factor;

[0011] S13. Calculate the decomposition rate of organic carbon in the estuary under the scenario of no reservoir construction.

[0012] S14. Calculate the carbon dioxide emission equivalent of estuary sedimentation under the scenario of no reservoir construction.

[0013]

[0014] X Es It is the CH4 / CO2 ratio of carbon emissions in the estuary environment;

[0015] S15. Obtain the total carbon dioxide emission equivalent (GWP) under the scenario without reservoir construction. 1 :

[0016]

[0017] S2. Calculate the total carbon dioxide emission equivalent (GWP) after the reservoir is built. 2 The specific steps are as follows:

[0018] S21. Calculate the carbon dioxide emission equivalent of the reservoir.

[0019]

[0020] Where K Re This represents the interception coefficient of organic carbon in the reservoir. WRT Re The hydraulic residence time of the reservoir is yr; V Re The reservoir capacity is measured in m³; D Re The discharge flow rate from the reservoir is m³ / s; k Re X represents the decomposition rate of organic carbon in the reservoir. Re The CH4 / CO2 ratio of carbon emissions from the reservoir environment;

[0021] S22. Calculate the carbon dioxide emission equivalent of river sedimentation after the construction of the reservoir.

[0022]

[0023] in This represents the amount of organic carbon input into the river channel under the reservoir construction scenario.

[0024] The input amount of estuarine organic carbon in the reservoir construction scenario, in tons.

[0025] S23. Calculate the carbon dioxide emission equivalent of river estuary sedimentation after reservoir construction.

[0026]

[0027] in The decomposition rate of organic carbon in the estuary under the reservoir construction scenario;

[0028] S24. Obtain the total carbon dioxide emission equivalent (GWP) under the reservoir construction scenario. 2 :

[0029]

[0030] S3, Net Carbon Emissions from Reservoir Silt (GWP) 0 For: GWP 0 =GWP 2 -GWP 1 .

[0031] Further, the river organic carbon flux C0 is the product of the river sediment flux and the organic carbon content; the method for determining the organic carbon content includes the following steps:

[0032] River sediment was collected and frozen at low temperature. After being dried in a freeze dryer, inorganic carbon components were removed by fumigation with hydrochloric acid. The sediment was wrapped in a tin boat to make a sample. The organic carbon content of the sample was determined on a CHNOS elemental analyzer.

[0033] Before use, the CHNOS elemental analyzer was tested for precision by using acetanilide as a standard sample, performing three blank injections, three injections without weighing the standard sample, and three weighed injections of the standard sample.

[0034] Furthermore, the hydraulic residence time (WRT) of the river channel Ri The calculation can be performed in one of the following ways:

[0035] Method 1:

[0036] Where s is the river length and v is the river flow velocity;

[0037] Method 2:

[0038] Where h is the reservoir elevation, α is the river gradient, and D Re This refers to the discharge flow from the reservoir.

[0039] Furthermore, the CH4 / CO2 ratio X in the river environment... Ri The determination steps are as follows:

[0040] A1. Determination of CO2 concentration on the river surface using gas chromatography. CH4 concentration at water surface

[0041] A2. A volume of V is extracted from the river channel. W The liquid was placed into a container and then filled with a volume of V. h High-purity nitrogen or air of known concentration was used, and the mixture was vigorously shaken for 2 minutes. After equilibration for 2 hours, the CO2 concentration in the headspace was determined by gas chromatography. and CH4 gas concentration

[0042] Calculate the theoretical concentration of CO2 after equilibrium.

[0043] in The Henry's constant coefficient for CO2 is 3.491 × 10⁻⁶. -2 molL -1 atm -1 , This refers to the partial pressure of CO2 in the headspace;

[0044] Calculate the theoretical concentration of CH4 after equilibrium.

[0045] in The Bunsen constant for CH4 has a value of 0.0319.

[0046] A3. Monitor the wind speed U at point z above the water surface. z And convert it to wind speed U at 10m above the water surface. 10 :

[0047]

[0048] Where C d10 The drag coefficient at 10m is taken as 0.0013; k is the Von Karman constant, taken as 0.41;

[0049] Calculate the mass transfer coefficient of CO2

[0050] Calculate the mass transfer coefficient of CH4

[0051] Where K 600 =2.07 + 0.215(U) 10 ) 1.7 , and Let be the Schmidt constants for CO2 and CH4 at the measurement temperature t, respectively. For freshwater, they are calculated using the following formula:

[0052]

[0053]

[0054] When U 10 When ≤3.7, n=-2 / 3, when U 10 When n > 3.7, n = -1 / 2;

[0055] A4. Calculate the diffusion flux of CO2 and CH4 respectively. and

[0056]

[0057]

[0058] Obtain the CH4 / CO2 ratio X in the river environment Ri :

[0059] Furthermore, the CH4 / CO2 ratio X in the estuarine environment... Es The determination steps are as follows:

[0060] The static chamber was placed on the water surface of the estuary, and the gas intake port was opened to equalize the internal and external pressures. The fan inside the chamber was turned on 10 seconds before sampling. Every 5 minutes, 20 mL of gas was extracted from the chamber using a syringe and stored in a vacuum sample bottle. Five samples were taken at each sampling point. The concentrations of CO2 and CH4 in each gas sample were measured using a gas chromatograph. Based on linear fitting, the rate of change of CO2 and CH4 concentrations inside the static chamber was calculated. and Obtain the CH4 / CO2 ratio X in the estuarine environment Es :

[0061] Furthermore, the decomposition rate of organic carbon in the estuary under the scenario without reservoir construction... for:

[0062] BE Re For the organic carbon burial rate of reservoirs, BE Re =30.7 + 27.7 × logS Re S Re The sediment settling rate in the reservoir. Where δ is 210 Pb decay constant, Z Re The depth for determining the sediment settling rate in a reservoir is ReC0, where ReC0 represents the surface layer of the reservoir.210 Pb excess value, ReC Z For the reservoir at a depth of Z Re place 210 Pb excess value.

[0063] Furthermore, the decomposition rate k of the organic carbon in the reservoir Re for:

[0064] On the other hand, the present invention also discloses a system for calculating the net carbon emissions from reservoir siltation, comprising:

[0065] Total CO2 Emission Equivalent (GWP) under the scenario without storage 1 Module 1 is used to estimate the total carbon dioxide emission equivalent (GWP) under the scenario without a reservoir. 1 ;

[0066] Total CO2 Emissions Equivalent (GWP) after reservoir construction 2 Module 2 is used to estimate the total carbon dioxide emission equivalent (GWP) after the construction of the reservoir. 2 ;

[0067] Net carbon emissions (GWP) from reservoir sediment 0 Accounting module 3 is used to calculate based on GWP 0 =GWP 2 -GWP 1 Calculate the net carbon emissions (GWP) of reservoir sediment. 0 .

[0068] The present invention also discloses a computer storage medium storing a computer program, which, when executed by a processor, implements the method for calculating net carbon emissions from reservoir siltation as described above.

[0069] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method for calculating net carbon emissions from reservoir siltation as described above.

[0070] Beneficial Effects: This invention establishes the carbon emission relationships among various components of a reservoir-river (including the channel and estuary) system, transforming the actual carbon emissions of the reservoir into a relationship solely dependent on the reservoir's own parameters and the river's natural hydrology. This allows for the objective quantification of net carbon emissions from reservoir sedimentation. This invention eliminates the need for complex model simulations or long-term, extensive field sampling and monitoring; it directly calculates net carbon emissions caused by reservoir sedimentation using readily available parameters. The method is simple, feasible, intuitive, and practical. Attached Figure Description

[0071] Figure 1 A schematic diagram for calculating net carbon emissions from reservoir siltation.

[0072] Figure 2 This is a flowchart of the method for calculating net carbon emissions from reservoir siltation disclosed in this invention;

[0073] Figure 3 This is a schematic diagram of the composition of the reservoir silt net carbon emission accounting system disclosed in this invention;

[0074] Figure 4 A comparison chart showing the calculation results of net carbon emissions from sedimentation in the Three Gorges Reservoir. Detailed Implementation

[0075] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0076] This invention discloses a method for calculating the net carbon emissions from reservoir siltation. For example... Figure 1 As shown, calculating the net carbon emissions from reservoir sedimentation requires calculating the carbon emissions from the river channel and estuary before and after the reservoir's construction. In practice, it's impossible to use methods that span the entire reservoir construction period for carbon emission calculations. This embodiment establishes the carbon emission relationships between different parts of the reservoir-river system, thereby transforming the reservoir's actual carbon emissions into a relationship that depends only on the reservoir's own parameters and the river's natural hydrology. For example... Figure 2 As shown, the steps include:

[0077] S1. Calculate the total carbon dioxide emission equivalent (GWP) under the scenario without reservoir construction. 1 The specific steps are as follows:

[0078] S11, Based on the hydraulic residence time (WRT) of the river channel Ri Estimating the amount of organic carbon input to the estuary without reservoir construction based on river organic carbon flux (C0).

[0079]

[0080] Where K OC The degradation coefficient of organic carbon in the river channel:

[0081] K OC =0.3829×(WRT) Ri ) -0.45 (2)

[0082] River organic carbon flux C0 is the product of river sediment flux and organic carbon content; the method for determining the organic carbon content includes the following steps:

[0083] River sediment was collected and frozen in a -24°C freezer. After vacuum drying in a freeze dryer (FD-1A-50), inorganic carbon components were removed by fumigation with hydrochloric acid. The sediment was then wrapped in a tin boat to prepare a sample. The organic carbon content of the sample was determined on a CHNOS elemental analyzer (Elementar Vario EL III, Elementar Analysensysteme GmbH).

[0084] Before use, the CHNOS elemental analyzer was tested for precision by using acetanilide as a standard sample, performing three blank injections, three injections without weighing the standard sample, and three weighed injections of the standard sample.

[0085] The hydraulic residence time (WRT) of the river channel Ri The calculation can be performed in one of the following ways:

[0086] Method 1:

[0087] Where s is the river length and v is the river flow velocity; in this embodiment, the river flow velocity v is measured using a dual-frequency ADCP manufactured by RDI Corporation of the United States, with frequencies of 300kHz and 600kHz.

[0088] Method 2:

[0089] Where h is the reservoir elevation, α is the river gradient, and D Re This refers to the discharge flow from the reservoir.

[0090] S12. Calculate the carbon dioxide emission equivalent of river sedimentation under the scenario without reservoir construction.

[0091]

[0092] Where X Ri This is the CH4 / CO2 carbon emission ratio in the river environment, where K is the CH4-CO2-eq conversion factor. Here, it is based on 27.2 on a 100-year scale from the IPCC Sixth Assessment Report, and this value will be used in all subsequent calculations. The constants 3.67 and 1.33 in the above formula are the mass ratios of C converted to CO2 and CH4, respectively.

[0093] In this embodiment, the CH4 / CO2 emission value X in the river environment Ri The measurement was performed using a thin film boundary layer model, and the steps were as follows:

[0094] A1. Determination of CO2 concentration on the river surface using gas chromatography. CH4 concentration at water surface

[0095] A2. A volume of V is extracted from the river channel. W The liquid is placed into a container. This invention uses a 100ml syringe, removes air bubbles from the liquid, and then fills it with a volume of V. h High-purity nitrogen or air of known concentration was used, and the mixture was vigorously shaken for 2 minutes. After equilibration for 2 hours, the CO2 concentration in the headspace was determined by gas chromatography. and CH4 gas concentration

[0096] Calculate the theoretical concentration of CO2 after equilibrium.

[0097]

[0098] in The Henry's constant coefficient for CO2 is 3.491 × 10⁻⁶. -2 molL -1 atm -1 , This refers to the partial pressure of CO2 in the headspace;

[0099] Calculate the theoretical concentration of CH4 after equilibrium.

[0100]

[0101] in The Bunsen constant for CH4 has a value of 0.0319.

[0102] A3. Monitor the wind speed U at point z above the water surface. z And convert it to wind speed U at 10m above the water surface. 10 :

[0103]

[0104] Where C d10 The drag coefficient at 10m is taken as 0.0013; k is the Von Karman constant, taken as 0.41; calculate the mass transfer coefficient of CO2.

[0105]

[0106] Calculate the mass transfer coefficient of CH4

[0107]

[0108] Where K 600 =2.07 + 0.215(U) 10 ) 1.7 , and Let be the Schmidt constants for CO2 and CH4 at the measurement temperature t, respectively. For freshwater, they are calculated using the following formula:

[0109]

[0110]

[0111] When U 10 When ≤3.7, n=-2 / 3, when U 10 When n > 3.7, n = -1 / 2;

[0112] A4. Calculate the diffusion flux of CO2 and CH4 respectively. and

[0113]

[0114]

[0115] Obtain the CH4 / CO2 ratio X in the river environment Ri :

[0116]

[0117] S13. Calculate the decomposition rate of organic carbon in the estuary under the scenario of no reservoir construction.

[0118] In this embodiment,

[0119] BE Re For the organic carbon burial rate of reservoirs, BE Re =30.7 + 27.7 × logS Re S Re The sediment settling rate in the reservoir. Where δ is 210 Pb decay constant, Z Re The depth for determining the sediment settling rate in a reservoir is ReC0, where ReC0 represents the surface layer of the reservoir. 210 Pb excess value, ReC Z For the reservoir at a depth of Z Re place 210 Pb excess value.

[0120] S14. Calculate the carbon dioxide emission equivalent of estuary sedimentation under the scenario of no reservoir construction.

[0121]

[0122] X EsIt is the CH4 / CO2 ratio of carbon emissions in the estuarine environment; the CH4 / CO2 ratio of carbon emissions in the estuarine environment X Es The static chamber method was used for determination, and the steps were as follows:

[0123] The static chamber was placed on the water surface of the estuary. In this embodiment, the static chamber was cylindrical (base area: 330 cm², height: 20 cm), made of plexiglass, and equipped with a small fan inside. The chamber was lined with foam for buoyancy support. The gas intake port was opened to equalize the internal and external pressures. The fan inside the chamber was turned on 10 seconds before sampling to ensure uniform air mixing and stable sampling. Every 5 minutes, 20 mL of gas was extracted from the chamber using a syringe and stored in a vacuum sample vial. Five samples were taken at each sampling point, and the entire gas collection process took 20 minutes. The concentrations of CO₂ and CH₄ in each gas sample were measured using a gas chromatograph. Based on linear fitting, the rate of change of CO₂ and CH₄ concentrations within the static chamber was calculated. and Obtain the CH4 / CO2 ratio X in the estuarine environment Es :

[0124] S15. Obtain the total carbon dioxide emission equivalent (GWP) under the scenario without reservoir construction. 1 :

[0125] S2. Calculate the total carbon dioxide emission equivalent (GWP) after the reservoir is built. 2 The specific steps are as follows:

[0126] S21. Calculate the carbon dioxide emission equivalent of the reservoir.

[0127]

[0128] Where K Re This represents the interception coefficient of organic carbon in the reservoir. WRT Re The hydraulic residence time of the reservoir is yr; V Re The reservoir capacity is measured in m³; D Re The discharge flow from the reservoir is m 3 / s;k Re In this embodiment, the decomposition rate of organic carbon in the reservoir is given.

[0129] X Re The CH4 / CO2 ratio of carbon emissions in the reservoir environment is X; compared with the CH4 / CO2 ratio of carbon emissions in the estuary environment. Es The measurement method is similar to that used for the reservoir environmental carbon emission CH4 / CO2 value X. ReThe static box method was also used for measurement. The static box was cylindrical (base area: 330 cm²). 2 The static chamber (height: 20cm) is made of plexiglass and equipped with a small internal fan. Foam lining the sides provides buoyancy support. After placing the static chamber on the surface of the reservoir, the gas inlet is opened to equalize the internal and external pressures. The fan is turned on 10 seconds before sampling. Every 5 minutes, 20mL of gas is extracted from the chamber using a syringe and stored in a vacuum sample vial. Five samples are taken at each sampling point, for a total sampling time of 20 minutes. The concentrations of CO2 and CH4 in each gas sample are measured using gas chromatography. Based on linear fitting, the rate of change of CO2 and CH4 concentrations within the static chamber is calculated. and Obtain the CH4 / CO2 ratio X in the reservoir environment. Re :

[0130] S22. Calculate the carbon dioxide emission equivalent of river sedimentation after the construction of the reservoir.

[0131]

[0132] in This represents the amount of organic carbon input into the river channel under the reservoir construction scenario.

[0133] The input amount of estuarine organic carbon in the reservoir construction scenario, in tons.

[0134] S23. Calculate the carbon dioxide emission equivalent of river estuary sedimentation after reservoir construction.

[0135]

[0136] in The decomposition rate of organic carbon in the estuary under the reservoir construction scenario;

[0137] The organic carbon burial rate in the estuary under the reservoir construction scenario. The sediment settling rate at the river mouth under the scenario of reservoir construction;

[0138] in The depth for measuring sediment settling rate in the estuary under the reservoir construction scenario is given by Es2C0, where Es2C0 represents the surface sediment depth in the estuary under the reservoir construction scenario. 210 Pb excess value, EsC Z For the reservoir construction scenario, the estuary at a depth of place 210 Pb excess value.

[0139] S24. Obtain the total carbon dioxide emission equivalent (GWP) under the reservoir construction scenario. 2 :

[0140]

[0141] S3, Net Carbon Emissions from Reservoir Silt (GWP) 0 For: GWP 0 =GWP 2 -GWP 1 .

[0142] This embodiment also discloses a system for calculating the net carbon emissions from reservoir siltation, such as... Figure 2 As shown, it includes:

[0143] Total CO2 Emission Equivalent (GWP) under the scenario without storage 1 Module 1 is used to estimate the total carbon dioxide emission equivalent (GWP) under the scenario without a reservoir. 1 ;

[0144] Total CO2 Emissions Equivalent (GWP) after reservoir construction 2 Module 2 is used to estimate the total carbon dioxide emission equivalent (GWP) after the construction of the reservoir. 2 ;

[0145] Net carbon emissions (GWP) from reservoir sediment 0 Accounting module 3 is used to calculate based on GWP 0 =GWP 2 -GWP 1 Calculate the net carbon emissions (GWP) of reservoir sediment. 0 .

[0146] The present invention also discloses a computer storage medium storing a computer program, which, when executed by a processor, implements the method for calculating net carbon emissions from reservoir siltation as described above.

[0147] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method for calculating net carbon emissions from reservoir siltation as described above.

[0148] Net carbon emissions from sedimentation were calculated using the Three Gorges Reservoir as the case study. The Three Gorges Reservoir has an average annual capacity of 30.77 billion cubic meters. 3 The average annual discharge is approximately 12550.7 m³. 3The hydraulic residence time of the river is calculated using flow velocity and river length. The average flow velocity from the dam to the river mouth is 0.82 m / s, and the river length from the Three Gorges Dam to the Yangtze River estuary is 1893 km. In the scenario without the reservoir, the starting point of the river is taken as the tail end of the Three Gorges Reservoir after its construction, approximately 2556 km from the river mouth. The average annual sediment deposition in the Three Gorges Reservoir is 113.8 million tons, with an average organic carbon content of 3.2%, resulting in an organic carbon flux of 3,641,600 tons. The CH4 / CO2 ratio within the Three Gorges Reservoir is 0.001424; the CH4 / CO2 ratio of river carbon emissions is 0.000351; and the CH4 / CO2 ratio at the Yangtze River estuary is 0.000369. The organic carbon decomposition rate in the reservoir is 55%; the organic carbon decomposition rate at the river estuary is 75%.

[0149] like Figure 4 As shown, the calculation results indicate that the Three Gorges Dam reduced the carbon emission flux generated during the transport of organic carbon in the river. Without the Three Gorges Dam, the carbon emission CO2-eq would be 1.04 × 10⁻⁶. 7 Under the scenario of the Three Gorges Dam construction, carbon emissions (CO2-eq) are 7.96 × 10⁻⁶. 6 t / yr, decreased by approximately 23.4%.

Claims

1. A method for calculating net carbon emissions from reservoir siltation, characterized in that, Including the following steps: S1. Calculate the total carbon dioxide emission equivalent under the scenario without reservoir construction. The specific steps are as follows: S11. Based on the hydraulic residence time in the river channel and river organic carbon flux Estimate the amount of organic carbon input to the estuary under the scenario of no reservoir construction. : ; in This represents the degradation coefficient of organic carbon in the river channel. ; S12. Calculate the carbon dioxide emission equivalent of river sedimentation under the scenario without reservoir construction. : in Carbon emissions in the river environment value, yes CO2-eq conversion factor; S13. Calculate the decomposition rate of organic carbon in the estuary under the scenario of no reservoir construction. ; S14. Calculate the carbon dioxide emission equivalent of estuary sedimentation under the scenario of no reservoir construction. : Carbon emissions in the estuarine environment value; S15. Obtain the total carbon dioxide emission equivalent under the scenario without reservoir construction. : ; S2. Calculate the total carbon dioxide emission equivalent after the construction of the reservoir. The specific steps are as follows: S21. Calculate the carbon dioxide emission equivalent of the reservoir. : in This represents the interception coefficient of organic carbon in the reservoir. , The hydraulic residence time of the reservoir; ; For the reservoir capacity; This refers to the discharge flow from the reservoir. The decomposition rate of organic carbon in the reservoir. Carbon emissions from reservoir environment value; S22. Calculate the carbon dioxide emission equivalent of river sedimentation after the construction of the reservoir. : in This represents the amount of organic carbon input into the river channel under the reservoir construction scenario. ; This represents the amount of organic carbon input to the estuary under the reservoir construction scenario. ; S23. Calculate the carbon dioxide emission equivalent of river estuary sedimentation after reservoir construction. : in The decomposition rate of organic carbon in the estuary under the reservoir construction scenario; S24. Obtain the total carbon dioxide emission equivalent under the reservoir construction scenario. : S3, Net carbon emissions from reservoir siltation for: ; The decomposition rate of organic carbon in the estuary under the scenario without reservoir construction for: ; The organic carbon burial rate of the reservoir, , The sediment settling rate in the reservoir. , where δ is decay constant, Depth is used to determine the sediment settling rate in a reservoir. For the surface of the reservoir Excess value For the reservoir at a depth of place Excess value; The decomposition rate of organic carbon in the reservoir for: ; Under the proposed reservoir construction scenario, the decomposition rate of organic carbon in the estuary for: .

2. The method for calculating net carbon emissions from reservoir siltation according to claim 1, characterized in that, The river organic carbon flux The product of river sediment flux and organic carbon content; the method for determining the organic carbon content includes the following steps: River sediment was collected and frozen at low temperature. After being dried in a freeze dryer under vacuum, inorganic carbon components were removed by fumigation with hydrochloric acid. The sediment was then wrapped in a tin boat to prepare a sample. The organic carbon content of the sample was determined on a CHNOS elemental analyzer. Before use, the CHNOS elemental analyzer was tested for precision by using acetanilide as a standard sample, performing three blank injections, three injections without weighing the standard sample, and three weighed injections of the standard sample.

3. The method for calculating net carbon emissions from reservoir siltation according to claim 1, characterized in that, The hydraulic residence time of the river channel The calculation can be performed in one of the following ways: Method 1: in For the length of the river, The river's flow velocity; Method 2: ; in The elevation of the reservoir. To facilitate the dam construction, the river slope was lowered. This refers to the discharge flow from the reservoir.

4. The method for calculating net carbon emissions from reservoir siltation according to claim 1, characterized in that, Carbon emissions in the river environment value The determination steps are as follows: A1. Determination of river water surface using gas chromatography concentration and water surface concentration ; A2. The volume extracted from the river is... The liquid was placed into a container and then filled with a volume of [missing information]. High-purity nitrogen or air of known concentration was used, and the mixture was vigorously shaken for 2 minutes, allowed to equilibrate for 2 hours, and then analyzed by gas chromatography to determine the headspace composition. gas concentration and gas concentration ; After calculating equilibrium Theoretical concentration : in for Henry's constant coefficient, taking values ​​of , For the top of the sky partial pressure; After calculating equilibrium Theoretical concentration : in for The Bunsen constant has a value of 0.0319; A3. Monitoring above the water surface wind speed at the location And converted to wind speed at 10 m above the water surface. : in The drag coefficient at 10 m is taken as 0.0013; is the Von Karman constant, taken as 0.41; calculate mass transfer coefficient : calculate mass transfer coefficient : in , and They are respectively and The measured temperature is The Schmidt constant for freshwater is calculated using the following formula: when hour ,when hour ; A4. Calculate separately and diffusion flux and : Carbon emissions from the river environment value : .

5. The method for calculating net carbon emissions from reservoir siltation according to claim 1, characterized in that, Carbon emissions in the estuary environment value The determination steps are as follows: The static chamber was placed on the water surface of the estuary, and the gas sampling port was opened to equalize the internal and external pressures. The fan inside the chamber was turned on 10 seconds before sampling. Every 5 minutes, 20 mL of gas was extracted from the chamber using a syringe and stored in a vacuum sample bottle. Five samples were taken at each sampling point. The concentration of each gas sample was measured using a gas chromatograph. and The concentration within the static chamber was calculated based on linear fitting. and rate of concentration change and Carbon emissions in the estuary environment value : .

6. An accounting system for calculating the net carbon emissions from reservoir siltation according to claim 1, characterized in that, include: Total CO2 emission equivalent under the scenario without reservoir construction The estimation module (1) is used to estimate the total carbon dioxide emission equivalent under the scenario of no reservoir construction. , : ; Total carbon dioxide emission equivalent after the construction of the reservoir The estimation module (2) is used to estimate the total carbon dioxide emission equivalent after the construction of the reservoir. , ; Net carbon emissions from reservoir siltation The accounting module (3) is used to calculate based on Calculate the net carbon emissions from reservoir siltation .

7. A computer storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for calculating net carbon emissions from reservoir siltation as described in any one of claims 1-5.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for calculating net carbon emissions from reservoir siltation as described in any one of claims 1-5.

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