River ecological base flow estimation method and system based on improved wet weekly method

Abstract

The invention discloses a river ecological base flow estimation method based on an improved wet week method. The method comprises the following steps: S1, collecting data related to river ecological base flow; s2, the river flow of many years is decomposed according to months, and the decomposed river flow is combined with the hydraulic parameter form of the river section to calculate the monthly wetness week data of the river; s3, constructing a monthly wetted week-flow curve according to the monthly wetted week data of the river and the monthly decomposed river flow, and determining change points on the monthly wetted week-flow curve by adopting a slope 1 method and a curvature maximum method; s4, calculating the ecological flow required by the aquatic organisms according to the hydraulic parameter form of the river section and the hydraulic parameters of the aquatic organisms in different stages; s5, whether the obtained ecological base flow is larger than the calculated ecological flow needed by the aquatic organisms or not is judged, and if yes, the obtained ecological base flow is the final ecological base flow value of the river section; if not, the calculated ecological flow required by the aquatic organisms is the final ecological base flow value of the river section.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological base flow calculation, and in particular to a river ecological base flow estimation method and system based on an improved wetted perimeter method. Background Art

[0002] The wetted perimeter method, which is based on the relationship between the wetted perimeter and flow rate of the river, has a wide range of application value in calculating the ecological base flow of rivers. The wetted perimeter method uses the mutation point of the flow-wetted perimeter relationship curve as the ecological base flow value of the river section. Compared with the hydrological method, it can fully consider the river structure and hydraulic parameters such as river depth, flow velocity and wetted perimeter, so the base flow value obtained is more reasonable. The traditional wetted perimeter method constructs the flow-wetted perimeter curve using the flow and wetted perimeter data throughout the year, and then obtains an ecological base flow value for the whole year. However, the flow rates of northern rivers vary significantly in each month of the year, and a single base flow value is difficult to meet the actual situation of the river. Moreover, the traditional wetted perimeter method only considers the influencing factors related to hydrology and hydraulics, so there are the following technical problems:

[0003] 1. The baseflow value obtained by the traditional wetted perimeter method is only a single value within a year. In practice, a single baseflow value is difficult to meet the actual conditions of northern rivers.

[0004] 2. The traditional wetted perimeter method constructs the flow-wetted perimeter relationship based on various river hydraulic parameters, resulting in the resulting ecological base flow that may ignore the flow requirements of aquatic organisms at various growth stages, thereby threatening river biodiversity.

[0005] In response to the above technical problems, the present invention proposes a river ecological base flow estimation method and system based on an improved wetted perimeter method. Summary of the Invention

[0006] The purpose of the present invention is to address the defects of the existing technology and provide a river ecological base flow estimation method and system based on the improved wetted perimeter method, which takes the flow demand of aquatic organisms into consideration. The estimated ecological flow is more realistic and more conducive to the protection of river aquatic organisms.

[0007] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0008] A river ecological base flow estimation method based on the improved wetted perimeter method includes:

[0009] S1. Collect data related to river ecological base flow, including hydraulic parameters and morphology of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow;

[0010] S2. Decompose the multi-year river flow by month, and combine the decomposed river flow with the hydraulic parameters of the river section to calculate the monthly wetted perimeter data of the river;

[0011] S3. Construct a monthly wetted-period-discharge curve based on the monthly wetted-period data and the monthly river flow. Use the slope 1 method and the maximum curvature method to determine the change point on the monthly wetted-period-discharge curve. This change point is the ecological base flow.

[0012] S4. Calculate the ecological flow required by aquatic organisms based on the hydraulic parameters of the river section and the hydraulic parameters of aquatic organisms at different stages;

[0013] S5. Determine whether the ecological base flow obtained in step S3 is greater than the ecological flow required by aquatic organisms calculated in step S4. If so, the ecological base flow obtained in step S3 is the final ecological base flow value of the river section; if not, the ecological flow required by aquatic organisms calculated in step S4 is the final ecological base flow value of the river section.

[0014] Furthermore, the hydraulic parameter form of the river section in step S1 includes the water depth in the river channel, water flow velocity, cross-sectional area, wetted perimeter, river channel cross-sectional shape, and hydraulic radius.

[0015] Furthermore, the hydraulic parameters of the aquatic organisms at different stages in step S1 include water depth, flow rate, wetted perimeter, water surface width, water flow cross-sectional area, water surface area, and water temperature.

[0016] Furthermore, in step S3, the slope 1 method is used to determine the change point on the monthly wetted perimeter-flow curve, which is expressed as:

[0017]

[0018] Among them, Q S represents the ecological base flow calculated using the slope 1 method; d represents the river section parameters.

[0019] Furthermore, in step S3, the maximum curvature method is used to determine the change point on the monthly wetted perimeter-flow curve, which is expressed as:

[0020]

[0021] Among them, Q C represents the ecological base flow calculated using the maximum curvature method; d represents the river section parameter.

[0022] Accordingly, a river ecological base flow estimation system based on the improved wetted perimeter method is also provided, comprising:

[0023] The collection module is used to collect data related to river ecological base flow, including the hydraulic parameters of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow;

[0024] The first calculation module is used to decompose the multi-year river flow by month, and calculate the monthly wetted perimeter data of the river channel by combining the decomposed river flow with the hydraulic parameter morphology of the river channel section;

[0025] A construction module is used to construct a monthly wetted-period-discharge curve based on the monthly wetted-period data of the river and the river flow decomposed by month. The slope 1 method and the maximum curvature method are used to determine the change point on the monthly wetted-period-discharge curve. This change point is the ecological base flow.

[0026] The second calculation module is used to calculate the ecological flow required by aquatic organisms based on the hydraulic parameter morphology of the river section and the hydraulic parameters of aquatic organisms at different stages;

[0027] The judgment module is used to judge whether the obtained ecological base flow is greater than the calculated ecological flow required by aquatic organisms. If so, the obtained ecological base flow is the final ecological base flow value of the river section; if not, the calculated ecological flow required by aquatic organisms is the final ecological base flow value of the river section.

[0028] Furthermore, the hydraulic parameter form of the river section in the collection module includes the water depth in the river, water flow velocity, cross-sectional area, wetted perimeter, river section shape, and hydraulic radius.

[0029] Furthermore, the hydraulic parameters of the aquatic organisms in the collection module at different stages include water depth, flow rate, wetted perimeter, water surface width, water flow cross-sectional area, water surface area, and water temperature.

[0030] Furthermore, the construction module uses the slope 1 method to determine the change point on the monthly wetted perimeter-flow curve, which is expressed as:

[0031]

[0032] Among them, Q S represents the ecological base flow calculated using the slope 1 method; d represents the river section parameters.

[0033] Furthermore, the building module uses the maximum curvature method to determine the change points on the monthly wetted perimeter-flow curve, which is expressed as:

[0034]

[0035] Among them, Q C represents the ecological base flow calculated using the maximum curvature method; d represents the river section parameter.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. Unlike the traditional wetted perimeter method, which can only estimate a single ecological base flow value throughout the year, this method determines the ecological base flow value for each month by constructing a monthly flow-wetted perimeter curve. This method is more in line with the characteristics of annual flow differences in northern rivers, provides a theoretical basis for scientific and precise flow control according to seasonal and irrigation needs in river management, and saves water transfer costs.

[0038] 2. The traditional wetted perimeter method only considers the hydraulic factors of the river channel. This method takes the flow demand of aquatic organisms into account. The determined ecological base flow value can, to a certain extent, ensure the flow demand of river aquatic organisms at different growth stages, especially the ecological water demand during the breeding period. It is conducive to the growth of aquatic organisms and the protection of river biodiversity, and has important social and ecological benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a method for estimating river ecological base flow based on an improved wetted perimeter method provided in Example 1;

[0040] Figure 2 This is a schematic diagram of the morphological structure of a certain section of a river provided in Example 2;

[0041] Figure 3 This is a schematic diagram of the ecological base flow calculation results provided in Example 2. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0043] The purpose of the present invention is to address the defects of the prior art and provide a river ecological base flow estimation method and system based on the improved wetted perimeter method.

[0044] Example 1

[0045] This embodiment provides a river ecological base flow estimation method based on the improved wetted perimeter method. Figure 1 Shown, including:

[0046] S1. Data Collection: Collect data related to river ecological base flow, including hydraulic parameters and morphology of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow;

[0047] S2. Data Processing: Decompose multi-year river flow by month, and combine the decomposed river flow with the hydraulic parameters of the river section to calculate the monthly wetted perimeter data of the river;

[0048] S3. Construct monthly flow-wetted perimeter curves: Based on the monthly wetted perimeter data of the river channel and the monthly river flow, construct monthly wetted perimeter-flow curves. Use the slope 1 method and the maximum curvature method to determine the change point on the monthly wetted perimeter-flow curve. This change point is the ecological base flow.

[0049] S4. Determine the flow requirements of aquatic organisms: Calculate the ecological flow required by aquatic organisms based on the hydraulic parameters of the river section and the hydraulic parameters of aquatic organisms at different stages;

[0050] S5. Determine the ecological base flow of the river at the current section: Determine whether the ecological base flow obtained in step S3 is greater than the ecological flow required by aquatic organisms calculated in step S4. If so, the ecological base flow obtained in step S3 is the final ecological base flow value of the river section; if not, the ecological flow required by aquatic organisms calculated in step S4 is the final ecological base flow value of the river section.

[0051] In step S1, data related to river ecological base flow are collected, including hydraulic parameter morphology of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow.

[0052] The hydraulic parameters of the river section include:

[0053] Water depth (h): The depth of water in a river channel is one of the key parameters that determine the water-carrying capacity of a river channel.

[0054] Velocity (v): The speed of water flow. Usually the velocity at different locations on the cross section will be different. The distribution of velocity has an important influence on the energy and momentum transfer of the water flow.

[0055] Cross-sectional area (A): The area of ​​the river section through which water flows. It is directly related to the flow rate and is one of the basic parameters for calculating flow rate.

[0056] Wetted perimeter (X): The perimeter of the channel section in contact with water, which is very important for calculating the friction loss of water flow and the interaction between water flow and riverbed.

[0057] Hydraulic radius (R): This is the effective flow radius of water. It is related to the velocity of the water, the cross-sectional area, and the circumference of the pipe or channel. It is used to calculate hydraulic parameters such as the resistance coefficient and Reynolds number. The formula for calculating the hydraulic radius varies depending on the geometry of the pipe or channel.

[0058] River channel cross-sectional shape: including rectangle, trapezoid, semicircle, etc. Different cross-sectional shapes will affect the distribution and speed of water flow, and thus affect the hydraulic parameters.

[0059] Hydraulic parameters of aquatic organisms at different stages:

[0060] Water depth: Water depth is one of the basic conditions for the survival of aquatic organisms, especially for aquatic animals such as fish. A certain water depth can ensure their activity space and reproduction needs.

[0061] Flow rate: Flow rate affects the habitat selection and activity range of aquatic organisms. Different aquatic organisms have different adaptability to flow rates. An appropriate flow rate facilitates gas exchange and nutrient absorption for aquatic organisms, while excessively fast or slow flow rates can have adverse effects on them.

[0062] Wetted perimeter: The wetted perimeter is the length of a river's circumference in contact with water and is an important indicator of habitat quality. The relationship between wetted perimeter and flow rate reflects a river's ability to provide habitat for aquatic life.

[0063] Water surface width: Water surface width affects the fluidity of the river and the activity range of aquatic organisms, and plays an important role in maintaining the health of the river ecosystem.

[0064] Water-flow cross-sectional area: The water-flow cross-sectional area affects the distribution of water flow and the habitat of aquatic organisms, and is an important parameter for determining river flow and hydraulic conditions.

[0065] Water surface area: Water surface area is related to the evaporation of water bodies and the photosynthesis of aquatic plants, and has an important impact on the survival and reproduction of aquatic organisms.

[0066] Water temperature: Water temperature is a key factor affecting the growth and reproduction of aquatic organisms. Different types of aquatic organisms have different adaptability ranges to water temperature. Changes in water temperature will directly affect the physiological activities and distribution of aquatic organisms.

[0067] Rapids, slow currents, shallows and deep pools: these indicators of hydraulic form have an important impact on the habitat selection and behavior patterns of aquatic organisms. They are the main hydraulic forms that affect the number and distribution of species due to flow changes.

[0068] These hydraulic parameters collectively determine the hydraulic habitats of aquatic organisms and are crucial for protecting aquatic biodiversity and maintaining the health of river ecosystems. By simulating and calculating these parameters, we can determine the flow requirements for optimal survival of aquatic organisms, providing a scientific basis for the calculation and management of ecological flows.

[0069] Multi-year river flows include:

[0070] River flow measurements: These are usually obtained regularly from river observatories or hydrological stations, and reflect the changes in river flow at different times (e.g. daily, weekly or monthly).

[0071] Seasonal variation: River flows vary with the seasons, with flows increasing during the rainy season and decreasing during the dry season. Therefore, organizing flow data by month can help analyze and understand seasonal variations in river flows.

[0072] Historical streamflow data: These data may include continuous streamflow records covering multiple years and are used to analyze long-term trends and cyclical changes in river flows.

[0073] Relationship between flow and wetted perimeter: In the wetted perimeter method, there is a relationship between flow data and wetted perimeter (i.e., the circumference of the river in contact with water). By analyzing this data, the ecological base flow of the river can be determined, which is the minimum flow required to maintain the health of the river ecosystem.

[0074] Arrangement of flow data: These flow data are arranged by month to match the wet week data, because the wet week will also change with the water level, and this change usually has seasonal characteristics.

[0075] This flow data is used to construct flow-wetted perimeter curves, which in turn estimate the ecological base flow of the river. This estimate is crucial for the conservation and management of river ecosystems because it helps determine the minimum flow required by river ecosystems in different seasons and under different water conditions.

[0076] In step S2, the multi-year river flow is decomposed by month, and the decomposed river flow is combined with the hydraulic parameter morphology of the river section to calculate the monthly wetted perimeter data of the river.

[0077] The collected river flow data over the years are sorted by month to ensure that the data for each month are complete. Then, for each month's river flow, the corresponding wetted week data for each month are calculated based on the water level changes in the hydraulic parameter form of the river section.

[0078] In step S3, a flow-wetted perimeter curve is constructed monthly: a monthly wetted perimeter-flow curve is constructed based on the monthly wetted perimeter data of the river channel and the river flow decomposed by month, and the slope 1 method and the maximum curvature method are used to determine the change point on the monthly wetted perimeter-flow curve. This change point is the ecological base flow.

[0079] For each month's wetted perimeter data, use an appropriate mathematical model (such as a power function, exponential function, etc.) to fit the monthly wetted perimeter-flow curve. During the curve fitting process, it is necessary to determine the model parameters that best suit the data. The least squares method or other optimization techniques can be used. For example:

[0080] The slope 1 method is used to determine the change point on the monthly wetted perimeter-discharge curve, which is expressed as:

[0081]

[0082] Among them, Q S represents the ecological base flow calculated using the slope 1 method; d represents the river section parameter. For actual river sections, the power exponent d is generally less than 0.5.

[0083] The maximum curvature method is used to determine the change point on the monthly wetted perimeter-discharge curve, which can be expressed as:

[0084]

[0085] Among them, Q C represents the ecological base flow calculated using the maximum curvature method; d represents the river section parameter. For actual river sections, the power exponent d is generally less than 0.5.

[0086] In step S4, the ecological flow required by aquatic organisms is calculated based on the hydraulic parameter morphology of the river section and the hydraulic parameters of aquatic organisms at different stages.

[0087] The calculation method of the ecological flow required by aquatic organisms is as follows:

[0088] Identify critical life stages: Identify the critical stages of aquatic organisms in their life cycle, such as breeding, larval development, and adulthood. Each stage may have different flow requirements.

[0089] Collect ecological demand data: Collect data on the ecological flow requirements of specific aquatic organisms at various key stages.

[0090] Analyze hydraulic parameters: Analyze various hydraulic parameters that affect aquatic organisms, such as flow rate, water depth, wetted perimeter, hydraulic radius, etc., because these parameters directly affect the habitat quality of aquatic organisms.

[0091] Develop flow requirement models: Using data on hydraulic parameters and the ecological requirements of aquatic organisms, mathematical models are developed to estimate the minimum flow required for different life stages. These models may be based on the physiological requirements, behavioral habits, or population dynamics of aquatic organisms.

[0092] Consider seasonal variations: Take into account seasonal flow variations in rivers to ensure that rivers can provide sufficient flow at critical times when aquatic life needs it.

[0093] Integrate multi-species needs: If a variety of aquatic organisms exist in a river, the flow requirements of various organisms need to be integrated to ensure the overall health of the river ecosystem.

[0094] Apply ecological flow calculation methods: Use specific ecological flow calculation methods, such as the ecological hydraulic radius method and the multi-objective wetted perimeter method, to determine the ecological flow that meets the needs of all key substances.

[0095] Verification and adjustment: Verify the accuracy of the calculation results through field observations or model simulations, and make necessary adjustments based on actual conditions.

[0096] For example, if the calculation results show that a certain minimum flow is required during the fish breeding season to ensure spawning and the development of juveniles, then this flow value will be determined as the ecological base flow for that period.

[0097] In this embodiment, the ecological flow required for the growth stage of fish is calculated by combining the ecological flow data required for the growth stage of fish and the river morphology and structure, which is recorded as Q f .

[0098] In step S5, it is determined whether the ecological base flow obtained in step S3 is greater than the ecological flow required by aquatic organisms calculated in step S4. If so, the ecological base flow obtained in step S3 is the final ecological base flow value of the river section; if not, the ecological flow required by aquatic organisms calculated in step S4 is the final ecological base flow value of the river section.

[0099] Comparison Q S and Q f The size of, or compare Q C and Q f The maximum value is taken as the final ecological base flow value of the river section.

[0100] The beneficial effects of this embodiment are:

[0101] 1. Unlike the traditional wetted perimeter method, which can only estimate a single ecological base flow value throughout the year, this method determines the ecological base flow value for each month by constructing a monthly flow-wetted perimeter curve. This method is more in line with the characteristics of annual flow differences in northern rivers, provides a theoretical basis for scientific and precise flow control according to seasonal and irrigation needs in river management, and saves water transfer costs.

[0102] 2. The traditional wetted perimeter method only considers the hydraulic factors of the river channel. This method takes the flow demand of aquatic organisms into account. The determined ecological base flow value can, to a certain extent, ensure the flow demand of river aquatic organisms at different growth stages, especially the ecological water demand during the breeding period. It is conducive to the growth of aquatic organisms and the protection of river biodiversity, and has important social and ecological benefits.

[0103] Accordingly, this embodiment further provides a river ecological base flow estimation system based on the improved wetted perimeter method, comprising:

[0104] The collection module is used to collect data related to river ecological base flow, including the hydraulic parameters of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow;

[0105] The first calculation module is used to decompose the multi-year river flow by month, and calculate the monthly wetted perimeter data of the river channel by combining the decomposed river flow with the hydraulic parameter morphology of the river channel section;

[0106] A construction module is used to construct a monthly wetted-period-discharge curve based on the monthly wetted-period data of the river and the river flow decomposed by month. The slope 1 method and the maximum curvature method are used to determine the change point on the monthly wetted-period-discharge curve. This change point is the ecological base flow.

[0107] The second calculation module is used to calculate the ecological flow required by aquatic organisms based on the hydraulic parameter morphology of the river section and the hydraulic parameters of aquatic organisms at different stages;

[0108] The judgment module is used to judge whether the obtained ecological base flow is greater than the calculated ecological flow required by aquatic organisms. If so, the obtained ecological base flow is the final ecological base flow value of the river section; if not, the calculated ecological flow required by aquatic organisms is the final ecological base flow value of the river section.

[0109] Furthermore, the hydraulic parameter form of the river section in the collection module includes the water depth in the river, water flow velocity, cross-sectional area, wetted perimeter, river section shape, and hydraulic radius.

[0110] Furthermore, the hydraulic parameters of the aquatic organisms in the collection module at different stages include water depth, flow rate, wetted perimeter, water surface width, water flow cross-sectional area, water surface area, and water temperature.

[0111] Furthermore, the construction module uses the slope 1 method to determine the change point on the monthly wetted perimeter-flow curve, which is expressed as:

[0112]

[0113] Among them, Q S represents the ecological base flow calculated using the slope 1 method; d represents the river section parameters.

[0114] Furthermore, the building module uses the maximum curvature method to determine the change points on the monthly wetted perimeter-flow curve, which is expressed as:

[0115]

[0116] Among them, Q C represents the ecological base flow calculated using the maximum curvature method; d represents the river section parameter.

[0117] Example 2

[0118] The difference between the river ecological base flow estimation method based on the improved wetted perimeter method provided in this embodiment and the first embodiment is that:

[0119] like Figure 2 The figure shows the morphological structure of a certain section of the river. Figure 2 The structural diagram and collected water level data were used to calculate the wetted perimeter data at a specific flow rate. Based on the monthly wetted perimeter flow data, monthly flow-wetted perimeter curves were constructed and the points with the maximum slope and curvature on the curves were calculated. Combined with the water level data for this section, the river channel shape is approximately triangular, making it suitable for fitting the relationship using a power function. For ease of calculation, the wetted perimeter-flow data was dimensionless, using the following formula:

[0120]

[0121] Among them, q and p are relative ecological base flow and relative wet perimeter (Q m Select the maximum flow rate, P m The maximum wetted perimeter is selected, and d is a parameter related to the cross-sectional shape. For actual river sections, the power exponent d is generally less than 0.5. S is the ecological base flow calculated by the slope method, Q C is the ecological base flow calculated by the curvature method, m 3 / s.

[0122] Based on the collected data of aquatic organisms (mainly fish, including flow velocity and water depth data during the spawning period of fish) and river morphology and structure, the ecological flow Q required for the growth stage of fish is calculated. f , and Q f With Q S , Q C Compare and determine the appropriate ecological base flow. The fish growth flow mainly considers the fish growth flow during the breeding season. March to April is the breeding season for the Fenhe River's unique fish, the Walleye, and May to June is the breeding season for the four major carps. Figure 3 As can be seen from the figure, Q determined by the slope method S The values ​​in each month are greater than Q C , except March, the rest of Q S The values ​​of are all within the flow range suitable for fish growth and can meet the flow demand of fish during the breeding season. S The value is greater than the maximum flow required for the reproduction of Walleye fish, and needs to be adjusted. Therefore, the maximum flow rate during the fish breeding period Q is taken. fmax (4.41m3 / s) is the ecological base flow of the month. In summary, the ecological base flow values ​​for the whole year are determined to be 0.49m 3 / s,0.77m 3 / s,4.41m 3 / s,0.76m 3 / s,1.16m 3 / s,1.16m 3 / s,1.17m3 / s,1.68m 3 / s,0.96m 3 / s,1.04m 3 / s,0.98m 3 / s,0.64m 3 / s.

[0123] By improving the traditional wetted perimeter method, on the one hand, the monthly ecological base flow was obtained, providing a theoretical basis for river management throughout the year; on the other hand, the ecological base flow determined based on the flow demand of river aquatic organisms meets the needs of the local river aquatic organism growth stage, is conducive to the reproduction and growth of aquatic organisms, and further protects the river's biodiversity.

[0124] Example 3

[0125] The difference between the river ecological base flow estimation method based on the improved wetted perimeter method provided in this embodiment and the first embodiment is that:

[0126] In order to improve the accuracy of ecological base flow estimation, this embodiment also combines environmental gradient and seasonal variation factors, specifically:

[0127] In the data collection of step S1, in addition to the hydraulic parameter morphology of the river section, the hydraulic parameters of aquatic organisms at different stages, and the multi-year river flow, this embodiment also needs to collect data on environmental gradient and seasonal changes.

[0128] 1. Improve the Tennant method by introducing environmental gradient and seasonal coefficient

[0129] Environmental gradient: refers to the natural slope of the river and the impact of human activities on the river slope. This embodiment also takes into account the natural slope of the river and the impact of human activities on the river slope. Therefore, the environmental gradient is introduced as a correction factor to adjust the calculation of the ecological base flow, which is expressed as:

[0130] Q eco =Q base ×(1+α×S)

[0131] Among them, Q eco represents the adjusted ecological base flow; Q base represents the basic ecological base flow calculated based on the Tennant method; α represents the correction coefficient, which is used to adjust the impact of the environmental gradient; S represents the environmental gradient;

[0132] Seasonal coefficient: Based on the needs of aquatic organisms and changes in river flow in different seasons, seasonal coefficients are introduced to adjust the ecological base flow. For example, increasing the base flow during the fish breeding season to meet the breeding needs is expressed as:

[0133] Q eco =Q base×C season

[0134] Among them, C season Identification number seasonal coefficient, adjusted according to different seasons.

[0135] In the data processing of step S2, when decomposing the multi-year river flow by month, it is necessary to consider seasonal changes and adjust the flow data using seasonal coefficients.

[0136] Flow adjustments involve correcting flows in both recharged and unrecharged rivers to account for the impact of human activities on river flows. Based on historical flow data, changes in flow before and after human activities are analyzed to adjust ecological base flows.

[0137] In step S3, when constructing the monthly flow-wetted perimeter curve, the improved Tennant method is used to calculate the ecological base flow of each month, taking into account the influence of the environmental gradient and the seasonal coefficient.

[0138] The improved Tennant method is expressed as:

[0139]

[0140] Among them, W eco Represents the ecological base flow of the river, M i represents the average annual flow rate in the i-th month of the year; N i Indicates the percentage of ecological base flow corresponding to month i.

[0141] According to the improved formula, the monthly flow data is calculated to obtain the ecological base flow value for each month. The calculation results are adjusted according to the actual needs of aquatic organisms and river conditions to ensure that the ecological base flow value can not only meet the needs of aquatic organisms but also take into account the impact of human activities.

[0142] In determining the flow demand of aquatic organisms in step S4, when calculating the ecological flow required by aquatic organisms, the impact of seasonal changes on the demand of aquatic organisms is taken into account, and the ecological flow demand is adjusted using a seasonal coefficient.

[0143] Monthly ecological flow calculation: Calculate the monthly ecological flow based on the needs of aquatic organisms and seasonal factors. For example, during the fish breeding season, the flow may need to be increased to meet breeding needs; during the dry season, the flow may need to be reduced to protect the aquatic habitat.

[0144] In determining the river ecological base flow of the current section in step S5, when finally determining the river ecological base flow value, the ecological base flow value after considering the environmental gradient and seasonal coefficient is compared with the ecological flow required by aquatic organisms, and the larger value is taken as the final ecological base flow value.

[0145] Through the above method, environmental gradient and seasonal variation factors can be considered more comprehensively, thereby improving the accuracy and applicability of ecological base flow estimation.

[0146] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A river ecological base flow estimation method based on the improved wetted perimeter method, characterized in that: include: S1. Collect data related to river ecological base flow, including hydraulic parameter morphology of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow; S2. Decompose the multi-year river flow by month, and calculate the monthly wetted perimeter data of the river channel by combining the decomposed river flow with the hydraulic parameter morphology of the river channel section; S3. Construct a monthly wetted-period-discharge curve based on the monthly wetted-period data of the river and the monthly river flow. Use the slope 1 method and the maximum curvature method to determine the change point on the monthly wetted-period-discharge curve. This change point is the ecological base flow. S4. Calculate the ecological flow required by aquatic organisms based on the hydraulic parameters of the river section and the hydraulic parameters of aquatic organisms at different stages; S5. Determine whether the ecological base flow obtained in step S3 is greater than the ecological flow required by aquatic organisms calculated in step S4. If so, the ecological base flow obtained in step S3 is the final ecological base flow value of the river section; if not, the ecological flow required by aquatic organisms calculated in step S4 is the final ecological base flow value of the river section.

2. The method for estimating river ecological base flow based on the improved wetted perimeter method according to claim 1, characterized in that: The hydraulic parameters of the river section in step S1 include water depth in the river, water flow velocity, cross-sectional area, wetted perimeter, river section shape, and hydraulic radius.

3. The method for estimating river ecological base flow based on the improved wetted perimeter method according to claim 1, characterized in that: In step S1, the hydraulic parameters of aquatic organisms at different stages include water depth, flow rate, wetted perimeter, water surface width, water flow cross-sectional area, water surface area, and water temperature.

4. The method for estimating river ecological base flow based on the improved wetted perimeter method according to claim 1, characterized in that: In step S3, the slope 1 method is used to determine the change point on the monthly wetted period-flow curve, which is expressed as: Among them, Q S represents the ecological base flow calculated by the slope 1 method; d represents the river section parameter.

5. The method for estimating river ecological base flow based on the improved wetted perimeter method according to claim 1, characterized in that: In step S3, the maximum curvature method is used to determine the change point on the monthly wetted perimeter-flow curve, which is expressed as: Among them, Q C represents the ecological base flow calculated by the maximum curvature method; d represents the river section parameter.

6. A river ecological base flow estimation system based on the improved wetted perimeter method, characterized in that: include: The collection module is used to collect data related to river ecological base flow, including hydraulic parameter morphology of river sections, hydraulic parameters of aquatic organisms at different stages, and multi-year river flow; The first calculation module is used to decompose the multi-year river flow by month, and calculate the monthly wetted perimeter data of the river channel by combining the decomposed river flow with the hydraulic parameter morphology of the river channel section; A construction module is used to construct a monthly wetted-circumference-discharge curve based on the monthly wetted-circumference data of the river channel and the river flow decomposed by month, and the change point on the monthly wetted-circumference-discharge curve is determined by using the slope 1 method and the maximum curvature method. The change point is the ecological base flow; The second calculation module is used to calculate the ecological flow required by aquatic organisms based on the hydraulic parameter morphology of the river section and the hydraulic parameters of aquatic organisms at different stages; The judgment module is used to judge whether the obtained ecological base flow is greater than the calculated ecological flow required by aquatic organisms. If so, the obtained ecological base flow is the final ecological base flow value of the river section; if not, the calculated ecological flow required by aquatic organisms is the final ecological base flow value of the river section.

7. A river ecological base flow estimation system based on improved wetted perimeter method according to claim 6, characterized in that: The hydraulic parameter forms of the river section in the collection module include water depth in the river, water flow velocity, cross-sectional area, wetted perimeter, river section shape, and hydraulic radius.

8. The river ecological base flow estimation system based on the improved wetted perimeter method according to claim 6 is characterized in that: The hydraulic parameters of the aquatic organisms in the collection module at different stages include water depth, flow rate, wetted perimeter, water surface width, water flow cross-sectional area, water surface area, and water temperature.

9. The river ecological base flow estimation system based on the improved wetted perimeter method according to claim 6 is characterized in that: The construction module uses the slope 1 method to determine the change point on the monthly wetted week-flow curve, expressed as: Among them, Q S represents the ecological base flow calculated by the slope 1 method; d represents the river section parameter.

10. The river ecological base flow estimation system based on the improved wetted perimeter method according to claim 6, characterized in that: The building module uses the maximum curvature method to determine the change points on the monthly wetted perimeter-flow curve, which is expressed as: Among them, Q C represents the ecological base flow calculated by the maximum curvature method; d represents the river section parameter.

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