Adaptability Assessment Method for Ecological Flow Calculation Based on Aquatic Habitat Coupling

Abstract

This invention discloses an adaptive assessment method for ecological flow calculation based on aquatic habitat coupling, relating to the fields of hydrology, water resources, and aquatic ecological protection. The method includes: calculating ecological flow and its hydrological rhythm fit index with natural runoff using multiple methods based on natural runoff data; dividing daily flow events and calculating ecological water demand protection layer indicators in conjunction with the target fish's ecological window period; evaluating the habitat flow compliance index using a continuous suitability function based on the fish's life rhythm requirements; improving the Tennant method and quantifying habitat status using a continuous membership function; integrating the above indicators to construct an assessment model, and selecting the most suitable method through screening and comprehensive scoring. This invention solves the problems of existing assessment methods being single-dimensional, disconnected from aquatic organism life rhythms, and insufficient quantification of habitat suitability, achieving multi-dimensional quantitative assessment and providing reliable technical support for collaborative decision-making in water resource management and ecological protection.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary technical field of watershed water resources management and river ecological protection, specifically involving an adaptive assessment method for ecological flow calculation based on aquatic habitat coupling. Background Technology

[0002] Ecological flow is a key hydrological parameter for ensuring the structural integrity and functional stability of river ecosystems. The scientific validity and applicability of its calculation methods directly affect the effectiveness and sustainability of watershed ecological protection. Under the dual impacts of climate change and human activities, river hydrological conditions have undergone significant changes, and the quality of aquatic habitats has declined, placing higher demands on the accuracy and adaptability of ecological flow calculations.

[0003] Currently, over 200 methods for calculating ecological flow have been developed both domestically and internationally, including hydrological methods, hydraulic methods, and habitat simulation methods. Among these, hydrological methods are the most widely used mainstream methods due to readily available data and simple calculations. Typical examples include the Tennant method, the monthly flow variation method, the intra-annual distribution method, the monthly frequency calculation method, and the NGPRP method. However, these methods each have their own emphasis when calculating ecological flow, and their adaptability to different river hydrological rhythm characteristics, ecological protection goals, and habitat requirements varies significantly. Furthermore, existing assessment methods generally suffer from problems such as single-dimensionality and insufficient coupling with ecological elements, resulting in the determined ecological flow failing to match the multi-objective coordinated needs of rivers.

[0004] To address the aforementioned issues, some adaptive evaluation methods for ecological flow calculation methods have been proposed in the existing technology. For example, patent publication number CN121212511A describes an adaptive evaluation method for ecological flow calculation methods oriented towards ecological protection. This method calculates ecological flow magnitude indicators, quantifies hydrological rhythm matching degree using slope distance, constructs an ecological damage rate model to calculate guarantee rate indicators, and uses a product method to construct a comprehensive evaluation fitness function, thereby optimizing the ecological flow calculation method.

[0005] However, this method only compares the differences in changes between monthly-scale sequences by slope distance, ignoring features such as the direction and shape of natural daily flow fluctuations, making it difficult to comprehensively characterize the degree of adaptation of hydrological rhythms; its ecological guarantee rate assessment period is not linked to the key needs of aquatic organisms at specific life stages; it also lacks a quantitative assessment of habitat suitability, and the product method comprehensive evaluation cannot ensure that the optimal results meet the basic bottom-line requirements in all dimensions.

[0006] Therefore, it is necessary to further improve existing technologies and develop a multi-dimensional, quantitative, and systematic adaptive assessment system based on hydrological processes, driven by ecological needs, and constrained by habitat response. This system will enable a comprehensive evaluation and scientific optimization of different ecological flow calculation methods, providing support for the accurate determination of ecological flow. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an adaptability assessment method for ecological flow calculation based on aquatic habitat coupling. By integrating three major categories of indicators—hydrological rhythm adaptability, ecological water demand guarantee rate, and habitat suitability—a comprehensive evaluation model is constructed to achieve quantitative comparison and optimization of various ecological flow calculation methods. This provides reliable technical support for scientifically selecting the most suitable ecological flow calculation method for the coupling needs of the target river's hydrology, ecology, and habitat (aquatic habitat).

[0008] To achieve the above objectives, the present invention adopts the following technical solution: An adaptive assessment method for ecological flow calculation based on aquatic habitat coupling includes the following steps: Step S1: Based on the historical long-sequence natural daily runoff data of the target river section, integrate and generate the annual natural monthly average runoff sequence, the annual natural average runoff sequence, and the multi-year average natural monthly runoff, and use a variety of ecological flow calculation methods to calculate the river ecological flow respectively. Step S2: Using daily-scale natural runoff as a benchmark, calculate the hydrological rhythm matching index between the annual monthly average ecological flow obtained by various ecological flow calculation methods and the historical natural daily runoff process, including the average value deviation index, the average direction convergence index, and the average morphological similarity index. Step S3: Based on the frequency analysis, divide the daily flow events, combine the ecological window period of the target fish in the river channel, calculate the long-term guarantee rate of ecological flow in historical typical hydrological years and the weighted achievement rate of ecological window period under each ecological flow calculation method, and determine the guarantee coefficient of the target frequency of ecological flow in the driest month. Step S4: Based on the response requirements of the target fish's life rhythm to special flow processes, the percentage of days belonging to different flow event types of ecological flow obtained by each ecological flow calculation method within each window period is statistically analyzed. The habitat suitability of each window period is calculated using a continuous suitability function, and its average value is used as the habitat flow compliance index of each ecological flow calculation method. Step S5: Improve the traditional Tennant method by adjusting the assessment period to the ecological window period corresponding to the life rhythm of the target fish, and use a continuous membership function to replace the discrete rank score to quantify the habitat status index of the ecological flow obtained by each calculation method. Step S6: Integrate the average value deviation index, average direction convergence index, and average morphological similarity index into hydrological rhythm adaptation layer indicators; integrate the long-term guarantee rate, window period compliance rate, and dryest month guarantee coefficient into ecological water demand guarantee layer indicators; integrate the habitat flow compliance index and habitat status index into habitat suitability layer indicators; and construct a hierarchical ecological flow calculation method adaptability comprehensive evaluation model based on the screening threshold settings of each layer. Step S7: For the various ecological flow calculation methods participating in the evaluation, the hydrological rhythm adaptation layer screening and ecological water demand guarantee layer screening are performed in sequence. The method that passes both screenings is then used to conduct a comprehensive score of the habitat suitability layer, and the method with the highest comprehensive score is determined as the ecological flow calculation method that best meets the three-dimensional coupling needs of the target river's hydrology, ecology and habitat.

[0009] Specifically, in step S1, the calculation of river ecological flow includes the following steps: Step S11: Collect at least 20 years of historical long-series measured daily runoff data for the target river section, and obtain historical long-series natural daily runoff data for the target river section through hydrological reconstruction calculation; Step S12: Integrate the historical long-sequence natural daily runoff data of the target river section into the annual natural monthly average runoff sequence, the annual natural average runoff sequence, and the multi-year average natural monthly runoff. Step S13, assuming the following is adopted This hydrological method for calculating ecological flow yields the following river ecological flow: ,in , Number the ecological flow calculation method. For the first The first ecological flow calculation method determined by the method Monthly ecological flow.

[0010] Specifically, the average deviation index between the annual monthly average ecological flow and the historical natural daily runoff sequence mentioned in step S2. The calculation formula is: ; In the above formula, The year number is used as the serial number. , Total for the year; Represents the corresponding month. ; The date of the month. , Representing the Total number of days in a month; Representing the Year Month Daily natural runoff.

[0011] Specifically, the average directional convergence index between the annual monthly average ecological flow and the historical natural daily runoff sequence mentioned in step S2. The calculation formula is: ; In the above formula, Indicates the first Year Month The daily direction convergence indicator variable, when When, it indicates the first Under this method, the monthly variation direction of ecological flow is consistent with the daily rise and fall direction of natural daily runoff. When, it means that the two are in opposite directions; For the first The first method Monthly variation of ecological flow; For the first Year Month The daily fluctuation of natural daily runoff.

[0012] Specifically, the average morphological similarity index between the annual monthly average ecological flow and the historical natural daily runoff sequence mentioned in step S2. The calculation formula is: ; In the above formula, Indicates the first The first method of ecological flow calculation Coefficient of variation of daily deviation over the year; This represents the maximum value of the coefficient of variation across all years. For the first Standard deviation of daily deviation under this method; For the first The mean of daily deviations under these methods; For the first Year Month Daily natural runoff and the first day of the month The absolute deviation between ecological flows under these methods.

[0013] Specifically, the process of calculating the long-term guarantee rate, the ecological window period weighted compliance rate, and the guarantee coefficient of the ecological flow target frequency in step S3 is as follows: Step S31: Perform frequency analysis on the natural annual average runoff sequence of the target river section, and select the historical typical hydrological years corresponding to the frequency values ​​of 25%, 50%, 75% and 90%, and define them as historical typical high water year, historical typical normal water year, historical typical low water year and historical typical extremely low water year, respectively. Step S32: Based on the time series of natural daily runoff in typical historical hydrological years, calculate the average long-term guarantee rate of ecological flow under various ecological flow calculation methods. The calculation formula is: ; In the above formula, Indicates the type of a typical historical hydrological year; This represents a collection of typical historical hydrological years. ; Indicates the first Typical historical hydrological data of the year The total number of days in a month; Indicates the first Under the various ecological flow calculation methods, the first Typical historical hydrological data of the year Month The ecological flow target indicator variable is set to 1 if the daily natural runoff is not lower than the corresponding ecological flow, and 0 otherwise. Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; Step S33: Perform frequency ranking analysis on the historical long-term natural daily runoff sequence of the target river section, and select the daily runoff corresponding to the frequency values ​​of 25%, 50%, and 90%, respectively. , and ; Step S34: Using the three daily runoff volumes selected in step S33 as flow thresholds, and combining the dynamic duration and recovery interval, the natural daily runoff sequences of each historical typical hydrological year are divided into extremely low flow volumes. Low flow High-flow pulse Small flood and the Great Flood Five types; Step S35: Conduct an annual life rhythm survey of the main target fish species in the target river section, and divide it into four stages: upstream migration period, spawning and reproduction period, juvenile feeding period, and overwintering period. These are identified as four ecological window periods, and the specific start and end dates of each window period are determined. Step S36: Based on the differences in the importance of each ecological window period to the life rhythm of domestic fish and their special needs for flow events, differentiated weights are assigned. The weighted average method is used to calculate the average compliance rate of ecological flow under different ecological flow calculation methods during the ecological window periods of each historical typical hydrological year. The calculation formula is: ; In the above formula, , , and They represent the first time. Under the various ecological flow calculation methods, the first The ecological flow compliance rate during the upstream intrusion period, spawning and reproduction period, juvenile feeding period, and overwintering period of typical historical hydrological data within the year. , , and These are the compliance weighting coefficients for the corresponding window periods. , , and Satisfies the weight normalization constraint; Further, the first step described in step S36 The compliance rate of ecological flow during the upstream period of typical historical hydrological events within the year The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first The first typical historical hydrological year during the upstream period Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological runoff, and if it also falls under an extremely low flow event... The value is 1 if it also belongs to a low-traffic event. The value is 0.5 if the condition is met, otherwise it is 0. This represents the retrospective period. The moon; Indicates the upstream period of the target domestic fish The set of months included; In the first Typical historical hydrological upstream period within the year No. The total number of days in a month; Indicates the first Typical historical hydrological upstream period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; Further, the first step described in step S36 Ecological flow compliance rate during the spawning and reproduction period of typical historical hydrological conditions The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first During the spawning and reproduction period of a typical historical hydrological year, the first Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological flow, and if it also falls under the category of a major flood event... The value is 1 if it also belongs to a high-flow pulse event. or minor flood events The value is 0.5 if the condition is met, otherwise it is 0. This indicates that the period is for egg-laying and reproduction. The moon; Indicates the spawning and breeding season of the target fish. The set of months included; In the first Typical historical hydrological spawning and reproduction period within the year No. The total number of days in a month; Indicates the first Typical historical hydrological spawning and reproduction period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow.

[0014] Further, the first step described in step S36 Ecological flow compliance rate during the juvenile fish feeding period in typical historical hydrological years The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first Typical hydrological data during the feeding period of juvenile fish Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological flow, and if it also falls under the category of a minor flood event... The value is 1 if it also belongs to a high-flow pulse event. or major flood event The value is 0.5 if the condition is met, otherwise it is 0. This indicates that the fish are in the feeding stage of juvenile fish. The moon; Indicates the feeding period of the target juvenile fish. The set of months included; In the first Typical hydrological data for juvenile fish feeding period within the year No. The total number of days in a month; Indicates the first Typical hydrological data for juvenile fish feeding period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; Further, the first step described in step S36 Ecological flow compliance rate during the wintering period of typical historical hydrological conditions The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first During the wintering period of typical historical hydrological years, the first Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological runoff, and if it also falls under a low-flow event... The value is 1 if it also belongs to an extremely low traffic event. The value is 0.5 if the condition is met, otherwise it is 0. This indicates that it belongs to the overwintering period. The moon; Indicates the overwintering period of the target domestic fish The set of months included; In the first Typical historical hydrological overwintering period No. The total number of days in a month; Indicates the first Typical historical hydrological overwintering period Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; Step S37: From the historical natural monthly average runoff sequence of the target river section generated in Step S1, extract the month with the smallest natural monthly average runoff and its corresponding monthly runoff for each year to form the historical dryest natural monthly average runoff sequence, and perform frequency analysis on it to determine the frequency value of the dryest month ecological flow obtained by each ecological flow calculation method in the frequency analysis results. Based on this, the guarantee coefficient for the target frequency of ecological flow in the driest month is calculated. The calculation formula is: ; In the above formula, This represents the target frequency value of ecological flow in the driest month of the target river channel.

[0015] Specifically, the habitat flow compliance index mentioned in step S4 The calculation process is as follows: Step S41: Based on the traffic event classification criteria in step S34, determine the type of traffic event to which the monthly ecological traffic calculated by each method belongs, and calculate the ratio of the number of days of each type of traffic event to the total number of days in each ecological window period of the target fish. Step S42: Combining the life rhythm of the target fish with the response requirements of special flow processes in each ecological window period, construct continuous suitability functions for each ecological window period and calculate the habitat suitability for each window period. Furthermore, the construction process of the continuous suitability function for each ecological window period mentioned in step S42 is as follows: During the upstream migration period, the target fish prefer low-velocity environments. Extremely low flow rates and low-flow events are conducive to upstream migration, while high flow rates generated by high-flow pulses and flood events hinder upstream migration. Based on this, appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the upstream migration period is constructed as follows: ; In the above formula, Indicates the first The habitat suitability of ecological flows obtained under various ecological flow calculation methods during the upstream period; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the upstream period obtained by various ecological flow calculation methods to the total number of days in that window period; In the constructed upstream continuous fitness function, positive values ​​of the weight coefficients represent favorable migration events, while negative values ​​of the fitness weight coefficients represent unfavorable migration events. During the spawning and breeding season, the target fish require flood pulse stimulation to spawn, preferring high-flow pulses and flood events, and disliking extremely low-flow events. Furthermore, the larger the flood magnitude, the stronger the stimulus. Based on this, appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the spawning and breeding season is constructed as follows: ; In the above formula, Indicates the first The habitat suitability during the spawning and reproduction period based on the ecological flow calculated using various ecological flow calculation methods; , , and They represent the first time. The ratio of the number of days with extremely low flow, low flow, high flow pulses and flood events during the spawning and reproduction period to the total number of days in the window period, obtained under various ecological flow calculation methods; The overall contribution value of the flood pulse; For the first The ratio of the number of days in a major flood event to the total number of days in the spawning and reproduction window, wherein the flood events include minor flood events and major flood events; flood events are classified into four recurrence period levels. ,Right now These represent flood levels of less than once a year, once every 1-2 years, once every 2-5 years, and once every 5 years or more, respectively, and their corresponding ecological stimulus weights. The values ​​were set to 0.3, 0.6, 0.8, and 1.0 respectively. In the constructed continuous suitability function for the spawning and reproduction period, positive values ​​of the weight coefficients represent favorable spawning and reproduction events, while negative values ​​of the suitability weight coefficients represent events that hinder spawning and reproduction. During the feeding period of juvenile fish, the target domestic fish prefer a medium flow velocity environment. High flow pulses and minor floods are conducive to food aggregation and diffusion, while extremely low flow events and major floods are unfavorable to juvenile fish activity and feeding. Based on this, appropriate weight coefficients are configured for each flow event, and a continuous suitability function for the feeding period of juvenile fish is constructed as follows: ; In the above formula, Indicates the first The habitat suitability of ecological flow obtained under various ecological flow calculation methods during the feeding period of juvenile fish; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the juvenile fish feeding period to the total number of days in the window period, obtained under various ecological flow calculation methods. In the constructed continuous suitability function for the feeding period of juvenile fish, positive values ​​of the weight coefficients represent favorable food aggregation and diffusion events, while negative values ​​of the suitability weight coefficients represent events that hinder juvenile fish activity and feeding. During the overwintering period, the target fish species require stable flow rates and relatively high water depths. Low flow events are conducive to maintaining a stable overwintering environment, while high flow pulses and flood events will disrupt the stability of the overwintering habitat. Based on this, appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the overwintering period is constructed as follows: ; In the above formula, Indicates the first The habitat suitability during the overwintering period based on the ecological flow calculated using various ecological flow methods; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the wintering period to the total number of days in the window period, obtained under various ecological flow calculation methods. In the constructed continuous suitability function for the overwintering period, positive values ​​of the weight coefficients represent environmental events that are conducive to maintaining the overwintering habitat, while negative values ​​of the suitability weight coefficients represent environmental events that disrupt the overwintering habitat. Step S43: Based on the differences in the importance of each ecological window period to the life rhythm of domestic fish, assign differentiated weights, and then use a weighted summation method to calculate the habitat flow compliance index for the entire life cycle corresponding to different ecological flow calculation methods. The calculation formula is: ; In the above formula, , , and They represent the first time. The habitat suitability of ecological flow obtained under various ecological flow calculation methods during the upstream migration period, spawning and reproduction period, juvenile foraging period, and overwintering period. , , and These are the appropriate weighting coefficients for the corresponding window periods. , , and It satisfies the weight normalization constraint.

[0016] Specifically, in step S5, the habitat status index... The calculation process is as follows: Step S51: Based on the target fish ecological window period divided in step S35, the assessment period of the traditional Tennant method is adjusted to the upstream period, spawning and reproduction period, juvenile feeding period and overwintering period. Step S52: Based on the specific ecological flow and water depth requirements of the target fish species during each ecological window period, set the lower limit of the base flow standard according to the differences in the window periods: During the upstream migration period, the basic water depth should be guaranteed while taking into account the flow conditions to meet the migration needs, with the preferred lower limit being 20% ​​of the multi-year average flow; During the spawning and reproduction period, a high water level environment should be created to ensure the suspended development of drifting fish eggs, with the preferred lower limit being 40% of the multi-year average flow; During the juvenile feeding period, a medium water depth should be maintained to maintain the habitat of prey organisms, with the preferred lower limit being 30% of the multi-year average flow; During the overwintering period, a deep water environment should be maintained to improve the water body's heat retention capacity and stabilize the overwintering habitat, with the preferred lower limit being 30% of the multi-year average flow. Step S53: Construct a piecewise continuous membership scoring function, using the percentage of ecological flow value in the corresponding month of each window period to the multi-year average natural flow as the independent variable. This is directly mapped to obtain the continuous habitat status score for each month. The mathematical expression of the continuous membership function is: ; In the above formula, Indicates the first The habitat status of each month's ecological flow, obtained under various ecological flow calculation methods, is continuously scored within the corresponding ecological window period. This is the lower limit of the baseflow standard corresponding to the ecological window period; Step S54: Calculate the average habitat status score for the corresponding month within each window period, then take the arithmetic mean of the average scores for the four window periods, and define it as the habitat status index of this ecological flow calculation method. .

[0017] Specifically, the construction process of the adaptive comprehensive evaluation model based on the hierarchical ecological flow calculation method in step S6 is as follows: Step S61: Calculate the average deviation index. Average directional convergence index and average morphological similarity index Normalization , , Subsequently, the indicators were integrated into a hydrological rhythm adaptation layer, and the weights of each indicator were determined using an objective weighting method. , , The comprehensive score for hydrological rhythm adaptation was calculated using the weighted summation method. The calculation formula is: ; Step S62: Calculate the long-term guarantee rate. Window period compliance rate And the guarantee coefficient of the driest month Normalization , , Subsequently, these were integrated into ecological water demand protection layer indicators, and the weights of each indicator were determined using an objective weighting method. , , The comprehensive score for ecological water demand protection was calculated using the weighted summation method. The calculation formula is: ; Step S63: Calculate the habitat flow compliance index. and habitat status index Normalization , Subsequently, the indicators were integrated into a habitat suitability layer index, and the weights of each indicator were determined using an objective weighting method. , The comprehensive score of habitat suitability was calculated using the weighted summation method. The calculation formula is: ; Step S64: Based on the sensitivity of the target river section to hydrological rhythms and the goals of ecological protection and management, set the screening thresholds for the hydrological rhythm adaptation layer. Screening thresholds for ecological water demand protection layers ; Step S65: Based on the criteria of hierarchical screening of hydrological rhythm adaptation and ecological water demand guarantee, and comprehensive scoring and ranking of habitat suitability layers, construct a comprehensive assessment model for the adaptability of ecological flow calculation methods. This involves first screening the hydrological rhythm adaptation layers, and if... If it proceeds to the next screening layer, it will be eliminated; otherwise, the ecological water demand protection layer screening will be performed. Those that make it to the final habitat suitability layer will be selected based on a comprehensive score and ranking; otherwise, they will be eliminated.

[0018] Specifically, in step S7, if there is only one method that passes both the hydrological rhythm adaptation layer screening and the ecological water demand guarantee layer screening, then that method is directly determined as the optimal method; if no method passes both layers of screening, then feedback is provided to adjust or relax the screening thresholds and re-evaluate.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The method of this invention breaks through the limitations of traditional assessments that only focus on magnitude or a single hydrological indicator. It constructs a systematic assessment framework from three dimensions: hydrological rhythm adaptation, ecological water demand guarantee, and habitat suitability. Furthermore, it determines the weight of indicators through the objective weighting method (CRITIC), reducing the interference of subjective factors and avoiding the one-sidedness of single-dimensional evaluation.

[0020] 2. The method of the present invention integrates the average magnitude deviation index, the average direction convergence index, and the average morphological similarity index to comprehensively characterize the matching degree between ecological flow and natural runoff in terms of magnitude, fluctuation direction, and process morphology, thus making up for the shortcomings of existing technologies that only use slope distance to compare monthly-scale sequence changes.

[0021] 3. The method of this invention divides the target domestic fish into four ecological window periods: the upstream period, the spawning and reproduction period, the juvenile feeding period, and the overwintering period. Differentiated weights are configured to calculate the compliance rate of the window period. At the same time, the driest month guarantee coefficient is introduced to make the ecological water demand guarantee assessment accurately match the hydrological needs of fish at different life stages.

[0022] 4. The method of this invention constructs a continuous suitability function (non-discrete scoring) based on the response pattern of domestic fish to specific flow events during each ecological window period, and quantifies the habitat flow compliance index. At the same time, it improves the Tennant method by adjusting the assessment period to the ecological window period and using a piecewise continuous membership function to replace the discrete level score, thereby realizing the continuous quantification of habitat status.

[0023] 5. The method of this invention is based on long-sequence runoff data (which is easy to obtain). The weights of each layer, the division of the window period, the screening threshold and other parameters can be flexibly adjusted according to the hydrological characteristics and ecological protection goals of different watersheds. It does not require complex technical investment and can accurately screen ecological flow calculation methods that meet the hydrological-ecological-habitat coupling needs of the target river. It is applicable to assessment scenarios of different watersheds and different protected species. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the adaptability assessment method for the ecological flow calculation method based on aquatic habitat coupling of the present invention.

[0026] Figure 2 This is a schematic diagram of the annual average monthly ecological flow obtained under various ecological flow calculation methods in the embodiments of the present invention.

[0027] Figure 3 This is a time series curve of natural daily runoff for a typical historical hydrological year in the target river section of this invention.

[0028] Figure 4 This is the theoretical frequency curve of the lowest monthly runoff of the target river section in each year in this embodiment of the invention.

[0029] Figure 5 This is a hierarchical structure diagram of the adaptive comprehensive evaluation model of the ecological flow calculation method in this embodiment of the invention. Detailed Implementation

[0030] To facilitate understanding and implementation of the present invention by those skilled in the art, the various steps of the method proposed in this invention are described in detail below. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various modifications or alterations to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0031] Example Please see Figure 1 In this embodiment, taking the downstream river ecological control section of a sub-basin as an example, the adaptability assessment method of the ecological flow calculation method based on aquatic habitat coupling provided by the present invention is described in detail. The method of the present invention specifically includes the following steps: Step S1: Collect measured daily runoff data from 1953 to 2018 at the ecological control section of the downstream river in the sub-basin. Obtain historical long-sequence natural daily runoff data through hydrological restoration calculations, and integrate them into the annual natural monthly average runoff sequence, the annual natural average runoff sequence, and the multi-year average natural monthly runoff. In this embodiment, eight hydrological methods for calculating ecological flow are selected, including the monthly flow variation method, the DC method, the multi-year daily flow frequency distribution method, and the annual distribution method, and are assigned numbers. In order ;like Figure 2 As shown, Figure 2 (A) to Figure 2 The (H) in the text corresponds to the numbers in sequence as follows: The target river ecological flow is calculated using the ecological flow calculation method described above. In other regions or embodiments, other hydrological methods may also be used for ecological flow calculation. Step S2: As shown in Table 1 below, calculate the hydrological rhythm fit index between the annual monthly average ecological flow obtained from each ecological flow calculation method and the historical natural daily runoff process, including the average value deviation index. Average directional convergence index and average morphological similarity index ; The average deviation index between the annual monthly average ecological flow and the historical natural daily runoff sequence The calculation formula is: ; In the above formula, The year number is used as the serial number. , Total for the year; Represents the corresponding month. ; The date of the month. , Representing the Total number of days in a month; Representing the Year Month Daily natural runoff; The average directional convergence index between the annual average monthly ecological flow and the historical natural daily runoff series The calculation formula is: ; In the above formula, Indicates the first Year Month The daily direction convergence indicator variable, when When, it indicates the first Under this method, the monthly variation direction of ecological flow is consistent with the daily rise and fall direction of natural daily runoff. When, it means that the two are in opposite directions; For the first The first method Monthly variation of ecological flow; For the first Year Month The daily fluctuations in natural daily runoff; The average morphological similarity index between the annual monthly average ecological flow and the historical natural daily runoff sequence The calculation formula is as follows: ; In the above formula, Indicates the first The first method of ecological flow calculation Coefficient of variation of daily deviation over the year; This represents the maximum value of the coefficient of variation across all years. For the first Standard deviation of daily deviation under this method; For the first The mean of daily deviations under these methods; For the first Year Month Daily natural runoff and the first day of the month The absolute deviation between ecological flows under these methods.

[0032] Table 1. Results of Hydrological Rhythm Adaptability Assessment for Different Ecological Flow Calculation Methods in the Target River Channel ; Step S3: Based on frequency analysis, daily flow events are divided. Combined with the ecological window period of the target fish in the river channel, the long-term guarantee rate of ecological flow in historical typical hydrological years and the weighted achievement rate of ecological window period are calculated under each ecological flow calculation method. The guarantee coefficient of the target frequency of ecological flow in the driest month is determined. The results are shown in Table 2 below. The specific calculation process is as follows: Step S31: Perform frequency analysis on the natural annual average runoff sequence of the target river section, select the historical typical hydrological years corresponding to the frequency values ​​of 25%, 50%, 75% and 90%, namely 1961, 1989, 2008 and 1974, respectively, and define them as historical typical high water year, historical typical normal water year, historical typical low water year and historical typical extremely low water year, respectively. Step S32, as follows Figure 3 As shown, based on the time series of natural daily flows in typical historical high-water years, typical normal-water years, typical low-water years, and typical extremely low-water years, the average long-term guarantee rate of ecological flows under various ecological flow calculation methods is calculated. The calculation formula is: ; In the above formula, Indicates the type of a typical historical hydrological year; This represents a collection of typical historical hydrological years. ; Indicates the first Typical historical hydrological data of the year The total number of days in a month; Indicates the first Under the various ecological flow calculation methods, the first Typical historical hydrological data of the year Month The ecological flow target indicator variable is set to 1 if the daily natural runoff is not lower than the corresponding ecological flow, and 0 otherwise. Indicates the first Typical historical hydrological data of the year Month Natural runoff per day.

[0033] Table 2. Evaluation results of ecological flow guarantee rate for different ecological flow calculation methods for the target river channel ; Step S33: Perform frequency ranking analysis on the historical long-term natural daily runoff sequence of the target river section, and select the daily runoff corresponding to the frequency values ​​of 25%, 50%, and 90%, respectively. , and , respectively 595m 3 / d、250m 3 / d and 74.4m 3 / d, and use it as the traffic threshold for dividing traffic events; Step S34, at 595m 3 / d、250m 3 / d and 74.4m 3 Using three daily runoff rates as thresholds, combined with dynamic duration and recovery interval, the natural daily runoff sequences of each historical typical hydrological year were divided into extremely low flow rates. Low flow High-flow pulse Small flood and the Great Flood The five types of traffic events are categorized according to the specific criteria shown in Table 3 below. Table 3. Criteria for Classifying Traffic Events ; Step S35: Conduct an annual life rhythm survey of the main target fish species in the target river section, and divide it into four stages: upstream migration period, spawning and reproduction period, juvenile feeding period, and overwintering period. These are identified as four ecological window periods, and the specific start and end dates of each window period are determined. In this embodiment, the main domesticated fish in the selected target river section are black carp, grass carp, silver carp, and bighead carp. Among them, black carp has the greatest ecological and economic value, so black carp is selected as the target domesticated fish. The life rhythm of black carp is investigated, and the ecological window period is divided as follows: the upstream period is from March to April each year, the spawning and reproduction period is from May to July, the juvenile feeding period is from August to October, and the overwintering period is from November to February of the following year.

[0034] Step S36: Since the spawning and reproduction period is most important for the life rhythm of the target fish, its ecological flow compliance weighting coefficient is set to 0.4, and the compliance weighting coefficients for the other ecological window periods are all set to 0.2. The weighted average method is used to calculate the average compliance rate of ecological flow in each typical historical hydrological year ecological window period under different ecological flow calculation methods. The calculation formula is: ; In the above formula, , , and They represent the first time. Under the various ecological flow calculation methods, the first Ecological flow compliance rates during the annual upstream intrusion period, spawning and reproduction period, juvenile fish feeding period, and overwintering period of typical historical hydrological data; Among them, the first The compliance rate of ecological flow during the upstream period of typical historical hydrological events within the year The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first The first typical historical hydrological year during the upstream period Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological runoff, and if it also falls under an extremely low flow event... The value is 1 if it also belongs to a low-traffic event. The value is 0.5 if the condition is met, otherwise it is 0. This represents the retrospective period. The moon; Indicates the upstream period of the target domestic fish The set of months included; In the first Typical historical hydrological upstream period within the year No. The total number of days in a month; Indicates the first Typical historical hydrological upstream period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; The first Ecological flow compliance rate during the spawning and reproduction period of typical historical hydrological conditions The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first During the spawning and reproduction period of a typical historical hydrological year, the first Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological flow, and if it also falls under the category of a major flood event... The value is 1 if it also belongs to a high-flow pulse event. or minor flood events The value is 0.5 if the condition is met, otherwise it is 0. This indicates that the period is for egg-laying and reproduction. The moon; Indicates the spawning and breeding season of the target fish. The set of months included; In the first Typical historical hydrological spawning and reproduction period within the year No. The total number of days in a month; Indicates the first Typical historical hydrological spawning and reproduction period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; The first Ecological flow compliance rate during the juvenile fish feeding period in typical historical hydrological years The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first Typical hydrological data during the feeding period of juvenile fish Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological flow, and if it also falls under the category of a minor flood event... The value is 1 if it also belongs to a high-flow pulse event. or major flood event The value is 0.5 if the condition is met, otherwise it is 0. This indicates that the fish are in the feeding stage of juvenile fish. The moon; Indicates the feeding period of the target juvenile fish. The set of months included; In the first Typical hydrological data for juvenile fish feeding period within the year No. The total number of days in a month; Indicates the first Typical hydrological data for juvenile fish feeding period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; The first Ecological flow compliance rate during the wintering period of typical historical hydrological conditions The calculation formula is: ; In the above formula, Indicates the first Under the various ecological flow calculation methods, the first During the wintering period of typical historical hydrological years, the first Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological runoff, and if it also falls under a low-flow event... The value is 1 if it also belongs to an extremely low traffic event. The value is 0.5 if the condition is met, otherwise it is 0. This indicates that it belongs to the overwintering period. The moon; Indicates the overwintering period of the target domestic fish The set of months included; In the first Typical historical hydrological overwintering period No. The total number of days in a month; Indicates the first Typical historical hydrological overwintering period Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow.

[0035] Step S37, as follows Figure 4 As shown, from the historical natural monthly average runoff sequence of the target river section generated in step S1, the month with the smallest natural monthly average runoff and its corresponding monthly runoff are extracted year by year to form the historical dryest natural monthly average runoff sequence. Frequency analysis is performed on the historical dryest natural monthly average runoff sequence to determine the frequency values ​​of the dryest monthly ecological flow calculated by the monthly flow variation method, DC method, multi-year daily flow frequency analysis method, monthly minimum daily flow method, intra-annual distribution method, Texas method, NGPRP method, and monthly minimum method in normal water years in the frequency analysis results. The percentages are 30.80%, 95.57%, 95.08%, 68.94%, 86.50%, 76.48%, 70.26%, and 67.38%, respectively. Based on these percentages, the guarantee coefficient for the target frequency of ecological flow in the driest month is calculated. The calculation formula is: ; In the above formula, In this embodiment, the target frequency value of ecological flow for the dryest month of the target river channel is represented. =50%.

[0036] Step S4: Based on the target fish's circadian rhythm response to specific flow processes, statistically analyze the percentage of days with different flow event types corresponding to the ecological flow calculated by each method within each window period. Calculate the habitat suitability for each window period using a continuous suitability function, and use its average as the habitat flow compliance index for each ecological flow calculation method. The specific calculation process is as follows: Step S41: Based on the traffic event classification criteria in step S34, determine the type of traffic event to which the monthly ecological traffic calculated by each method belongs, and calculate the ratio of the number of days of each type of traffic event to the total number of days in each ecological window period of the target fish. Step S42: Combining the life rhythm of the target fish with the response requirements of special flow processes in each ecological window period, construct continuous suitability functions for each ecological window period and calculate the habitat suitability for each window period. The construction process of the continuous suitability function for each ecological window period is as follows: Based on the ecological requirement that the target fish prefers a low-flow-velocity environment during its upstream migration period, appropriate weight coefficients are configured for each flow event, and a continuous suitability function for the upstream migration period is constructed as follows: ; In the above formula, Indicates the first The habitat suitability of ecological flows obtained under various ecological flow calculation methods during the upstream period; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the upstream period obtained by various ecological flow calculation methods to the total number of days in that window period; In the constructed upstream continuous fitness function, positive values ​​of the weight coefficients represent favorable migration events, while negative values ​​of the fitness weight coefficients represent unfavorable migration events. Based on the ecological requirement that the target fish requires flood pulse stimulation for spawning during its spawning and breeding season, it prefers high-flow pulses and flood events, with stronger stimulation occurring at larger flood volumes. Appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the spawning and breeding season is constructed as follows: ; In the above formula, Indicates the first The habitat suitability during the spawning and reproduction period based on the ecological flow calculated using various ecological flow calculation methods; , , and They represent the first time. The ratio of the number of days with extremely low flow, low flow, high flow pulses and flood events during the spawning and reproduction period to the total number of days in the window period, obtained under various ecological flow calculation methods; The overall contribution value of the flood pulse; For the first The ratio of the number of days in a major flood event to the total number of days in the spawning and reproduction window, wherein the flood events include minor flood events and major flood events; flood events are classified into four recurrence period levels. ,Right now These represent flood levels of less than once a year, once every 1-2 years, once every 2-5 years, and once every 5 years or more, respectively, and their corresponding ecological stimulus weights. The values ​​were set to 0.3, 0.6, 0.8, and 1.0 respectively. Based on the ecological requirement that juvenile fish prefer a medium-velocity environment during their feeding period, appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the juvenile feeding period is constructed as follows: ; In the above formula, Indicates the first The habitat suitability of ecological flow obtained under various ecological flow calculation methods during the feeding period of juvenile fish; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the juvenile fish feeding period to the total number of days in the window period, obtained under various ecological flow calculation methods. Based on the ecological requirements of the target fish during the wintering period, which require stable flow and relatively high water depth, appropriate weight coefficients are configured for each flow event, and a continuous suitability function for the wintering period is constructed as follows: ; In the above formula, Indicates the first The habitat suitability during the overwintering period based on the ecological flow calculated using various ecological flow methods; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the wintering period to the total number of days in the window period, obtained under various ecological flow calculation methods. In the constructed continuous suitability function for the overwintering period, positive values ​​of the weight coefficients represent environmental events that are conducive to maintaining the overwintering habitat, while negative values ​​of the suitability weight coefficients represent environmental events that disrupt the overwintering habitat.

[0037] Step S43: Since the spawning and reproduction period is the most important for the life rhythm of the target fish, its appropriate weighting coefficient is set to 0.4, and the appropriate weighting coefficients for the other ecological window periods are all set to 0.2. Then, the habitat suitability of each window period is weighted and summed to calculate the habitat flow compliance index for the whole life cycle corresponding to different ecological flow calculation methods. , The calculation formula is as follows, and the calculation results are shown in Table 4 below; ; Table 4. Calculation results of habitat flow compliance index for different ecological flow calculation methods for the target river channel ; Step S5: Improve the traditional Tennant method by adjusting the assessment period to the ecological window period corresponding to the life rhythm of the target fish, and use a continuous membership function to replace the discrete rank scoring to quantify the habitat status index of ecological flow obtained by each calculation method. The specific calculation process is as follows: Step S51: Based on the target fish ecological window period divided in step S35, the assessment period of the traditional Tennant method is adjusted to the upstream period, spawning and reproduction period, juvenile feeding period and overwintering period. Step S52: Based on the specific ecological flow and water depth requirements of the target fish species during each ecological window period, set differentiated lower limits for baseflow standards for each window period. See Table 5 below for details; Table 5. Recommended Lower Limits of Baseflow Standards and Explanation of Ecological Requirements for Each Ecological Window Period ; Step S53: Construct a piecewise continuous membership scoring function, using the percentage of ecological flow value in the corresponding month of each window period to the multi-year average natural flow as the independent variable. This is directly mapped to obtain the continuous habitat status score for each month. The mathematical expression of the continuous membership function is: ; In the above formula, Indicates the first The habitat status of each month's ecological flow, obtained under various ecological flow calculation methods, is continuously scored within the corresponding ecological window period. This represents the lower limit of the baseflow standard for the corresponding ecological window period.

[0038] Step S54: Calculate the average habitat status score for the corresponding month within each window period, then take the arithmetic mean of the average scores for the four window periods, and define it as the habitat status index of this ecological flow calculation method. The calculation results are shown in Table 6 below.

[0039] Table 6. Calculation results of habitat status index for different ecological flow calculation methods for the target river channel. ; Step S6: Calculate the average deviation index. Average directional convergence index and average morphological similarity index Integrating into hydrological rhythm adaptation layer indicators will ensure long-term reliability. Ecological window period weighted compliance rate The guarantee coefficient for the target frequency of ecological flow in the driest month Integrate into ecological water demand protection layer indicators, and include habitat flow compliance index and habitat status index The indicators were integrated into a habitat suitability layer index, and based on the screening thresholds for each layer, a hierarchical comprehensive assessment model for the adaptability of ecological flow calculation methods was constructed. The specific construction process is as follows: The deviation index of the normalized average value within the hydrological rhythm adaptation layer. Average directional convergence index Average morphological similarity index and the normalized long-term guarantee rate within the ecological water demand protection layer Ecological window period weighted compliance rate Guarantee coefficient for the target frequency of ecological flow in the driest month and the normalized habitat flow compliance index within the habitat suitability layer. Habitat status index The weights of each indicator were determined using an objective weighting method, and then the comprehensive score for hydrological rhythm adaptation was calculated using a weighted summation method. Comprehensive score for ecological water demand guarantee Habitat suitability comprehensive score ; In this embodiment, the CRITIC method is selected as the objective weighting method. In other regions or embodiments, other objective weighting methods may also be used, depending on the actual applicability. Based on the CRITIC method, the calculation process for determining the objective weights of individual indicators at each layer is as follows: Step S611: Calculate the standard deviation of each indicator within the same layer under different ecological flow calculation methods, and quantify its information content: ; In the above formula, Represents the first in the same layer The standard deviation of the indicators; Representing the Various ecological flow calculation methods within the same layer The normalized values ​​of the indicators; within the hydrological rhythm adaptation layer, These correspond sequentially to the average value deviation index, the average direction convergence index, and the average morphological similarity index; within the ecological water demand protection layer... These correspond to the long-term guarantee rate, the window period compliance rate, and the dryest month guarantee coefficient, respectively; within the habitat suitability layer, These correspond to the habitat flow compliance index and the habitat status index, respectively. Representing the The sample mean of the indicator. .

[0040] Step S612: Calculate any two indices within the same layer. and correlation coefficient : ; In the above formula, This represents the Pearson correlation coefficient function, used to measure the degree of linear correlation between two variable series, with a value range of [value missing]. ; and Representing the first in the same layer Item and the first The sequence of normalized values ​​for each indicator, where each element corresponds to the normalized value of the indicator under each ecological flow calculation method. , , .

[0041] Step S613: Calculate the first [item] within the same layer. The degree of conflict between this indicator and other indicators : ; Step S614: Calculate the first [item] within the same layer. The comprehensive information content of each indicator : ; Step S615: Normalize the total information to obtain the objective weights of each indicator within the same layer. : ; In this embodiment, the objective weights of the average magnitude deviation index, average direction convergence index, and average morphological similarity index within the hydrological rhythm adaptation layer are calculated to be 0.379, 0.317, and 0.304, respectively. The objective weights of the long-term guarantee rate, window period compliance rate, and dryest month guarantee coefficient within the ecological water demand guarantee layer are 0.370, 0.330, and 0.300, respectively. The objective weights of the habitat flow compliance index and habitat status index within the habitat suitability layer are 0.497 and 0.503, respectively. Therefore, the comprehensive score for hydrological rhythm adaptation is calculated. Comprehensive score for ecological water demand guarantee Habitat suitability comprehensive score The calculation formulas are as follows: ; ; ; Step S62: Based on the sensitivity of the target river section to hydrological rhythms and the goals of ecological protection and management, set the screening thresholds for the hydrological rhythm adaptation layer. Screening thresholds for ecological water demand protection layers In this embodiment, they are respectively set as , ; Step S63, as follows Figure 5 As shown, based on the criteria of hierarchical screening of hydrological rhythm adaptation and ecological water demand guarantee, and comprehensive scoring and ranking of habitat suitability layers, an adaptive comprehensive evaluation model for ecological flow calculation methods is constructed. This involves first performing the hydrological rhythm adaptation layer screening, and if... If it proceeds to the next screening layer, it will be eliminated; otherwise, the ecological water demand protection layer screening will be performed. Those that make it to the final habitat suitability layer will be selected based on a comprehensive score and ranking; otherwise, they will be eliminated.

[0042] Step S7: For the various ecological flow calculation methods participating in the evaluation, perform hydrological rhythm adaptation layer screening and ecological water demand guarantee layer screening in sequence. For methods that pass both screening layers, conduct a comprehensive score of habitat suitability layer, and determine the ecological flow calculation method with the highest comprehensive score as the most suitable for the three-dimensional coupling needs of the target river's hydrology, ecology, and habitat. If only one method passes both hydrological rhythm adaptation layer screening and ecological water demand guarantee layer screening, then directly determine that method as the optimal method. If no method passes both screening layers, then provide feedback to adjust or relax the screening threshold and re-evaluate.

[0043] In this embodiment, the eight selected ecological flow calculation methods were first screened using a hydrological rhythm adaptation layer. Only the multi-year daily flow frequency distribution method had a hydrological rhythm adaptation comprehensive score less than the threshold and failed the first layer of screening. The other seven methods passed the first layer and proceeded to the next layer. Next, after screening using an ecological water demand guarantee layer, only the monthly flow variation method had an ecological water demand guarantee comprehensive score less than the threshold and failed the second layer of screening. The other six methods passed the second layer and proceeded to the final layer. Finally, based on the habitat suitability layer comprehensive score, the DC method scored 0.08, the monthly minimum daily flow method scored 0.45, and the annual distribution method scored 0.50. The Texas method scored 0.17, the NGPRP method scored 0.62, and the monthly minimum method for normal water year scored 0.48. Among them, the NGPRP method ranked the highest in comprehensive score, indicating that this method is most suitable for the coupling needs of the target river's hydrological rhythm characteristics, ecological water demand guarantee requirements, and habitat suitability, and can be used as the optimal method for calculating the ecological flow of the target river section. The annual distribution method, the monthly minimum method for normal water year, and the monthly minimum daily flow method scored the next highest in comprehensive score and can be used as alternative engineering solutions. The other methods cannot simultaneously meet the core needs of the coordinated protection of hydrology, ecology, and habitat of the target river section and are not suitable for calculating the ecological flow of this river section.

[0044] In summary, the ecological flow process determined by the NGPRP method ultimately selected in this invention can comprehensively meet the core needs of the target river in multiple dimensions, including hydrological rhythm adaptation, ecological water demand guarantee, and habitat suitability, thus providing excellent living conditions for the river ecosystem. Furthermore, this invention employs a hierarchical progressive screening mechanism with the life rhythm of the target species as the core constraint, achieving a comprehensive and quantitative assessment from hydrological rhythm adaptation and ecological water demand guarantee to habitat suitability. This fundamentally solves the common industry problems of traditional ecological flow calculation methods, such as a single adaptive assessment dimension, disconnect from aquatic organism life rhythms, and coarse habitat suitability assessment. The assessment results can accurately match the aquatic organism protection and ecological health needs of the target river and effectively support the coordinated development goals of watershed water resource allocation and ecological protection.

[0045] The above are merely preferred embodiments of the present invention and do not constitute a limiting interpretation of the present invention. Those skilled in the art can make equivalent modifications, variations, and optimizations to the above embodiments without departing from the technical essence of the present invention, and all resulting equivalent embodiments fall within the protection scope of the present invention.

Claims

1. An adaptability assessment method for ecological flow calculation based on aquatic habitat coupling, characterized in that, Includes the following steps: Step S1: Based on the historical long-sequence natural daily runoff data of the target river section, integrate and generate the annual natural monthly average runoff sequence, the annual natural average runoff sequence, and the multi-year average natural monthly runoff, and use a variety of ecological flow calculation methods to calculate the river ecological flow respectively. Step S2: Using daily-scale natural runoff as a benchmark, calculate the hydrological rhythm matching index between the annual monthly average ecological flow obtained by various ecological flow calculation methods and the historical natural daily runoff process, including the average value deviation index, the average direction convergence index, and the average morphological similarity index. Step S3: Based on the frequency analysis, divide the daily flow events, combine the ecological window period of the target fish in the river channel, calculate the long-term guarantee rate of ecological flow in historical typical hydrological years and the weighted achievement rate of ecological window period under each ecological flow calculation method, and determine the guarantee coefficient of the target frequency of ecological flow in the driest month. Step S4: Based on the response requirements of the target fish's life rhythm to special flow processes, the percentage of days belonging to different flow event types of ecological flow obtained by each ecological flow calculation method within each window period is statistically analyzed. The habitat suitability of each window period is calculated using a continuous suitability function, and its average value is used as the habitat flow compliance index of each ecological flow calculation method. Step S5: Improve the traditional Tennant method by adjusting the assessment period to the ecological window period corresponding to the life rhythm of the target fish, and use a continuous membership function to replace the discrete rank score to quantify the habitat status index of the ecological flow obtained by each calculation method. Step S6: Integrate the average value deviation index, average direction convergence index, and average morphological similarity index into hydrological rhythm adaptation layer indicators; integrate the long-term guarantee rate, window period compliance rate, and dryest month guarantee coefficient into ecological water demand guarantee layer indicators; integrate the habitat flow compliance index and habitat status index into habitat suitability layer indicators; and construct a hierarchical ecological flow calculation method adaptability comprehensive evaluation model based on the screening threshold settings of each layer. Step S7: For the various ecological flow calculation methods participating in the evaluation, the hydrological rhythm adaptation layer screening and ecological water demand guarantee layer screening are performed in sequence. The method that passes both screenings is then used to conduct a comprehensive score of the habitat suitability layer, and the method with the highest comprehensive score is determined as the ecological flow calculation method that best meets the three-dimensional coupling needs of the target river's hydrology, ecology and habitat.

2. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 1, characterized in that, The calculation of river ecological flow in step S1 includes the following steps: Step S11: Collect at least 20 years of historical long-series measured daily runoff data for the target river section, and obtain historical long-series natural daily runoff data for the target river section through hydrological reconstruction calculation; Step S12: Integrate the historical long-sequence natural daily runoff data of the target river section into the annual natural monthly average runoff sequence, the annual natural average runoff sequence, and the multi-year average natural monthly runoff. Step S13, assuming the following is adopted This hydrological method for calculating ecological flow yields the following river ecological flow: ,in , Number the ecological flow calculation method. For the first The first ecological flow calculation method determined by the method Monthly ecological flow.

3. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 2, characterized in that, The calculation formulas for each hydrological rhythm adaptation index in step S2 are as follows: The average deviation index between the annual monthly average ecological flow and the historical natural daily runoff sequence The calculation formula is: ； In the above formula, For year serial number, , Total for the year; Represents the corresponding month. ; The date of the month. , Representing the Total number of days in a month; Representing the Year Month Daily natural runoff; The average directional convergence index between the annual average monthly ecological flow and the historical natural daily runoff series The calculation formula is: ； In the above formula, Indicates the first Year Month The daily direction convergence indicator variable, when When, it indicates the first Under this method, the monthly variation direction of ecological flow is consistent with the daily rise and fall direction of natural daily runoff. When, it means that the two are in opposite directions; For the first The first method Monthly variation of ecological flow; For the first Year Month Daily fluctuations in natural daily runoff; The average morphological similarity index between the annual monthly average ecological flow and the historical natural daily runoff sequence The calculation formula is: ； In the above formula, Indicates the first The first method of ecological flow calculation Coefficient of variation of daily deviation over the year; This represents the maximum value of the coefficient of variation across all years. For the first Standard deviation of daily deviation under this method; For the first The mean of daily deviations under these methods; For the first Year Month Daily natural runoff and the first day of the month The absolute deviation between ecological flows under these methods.

4. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 3, characterized in that, The process of calculating the long-term guarantee rate, the ecological window period weighted compliance rate, and the guarantee coefficient of the ecological flow target frequency in step S3 is as follows: Step S31: Perform frequency analysis on the natural annual average runoff sequence of the target river section, and select the historical typical hydrological years corresponding to the frequency values ​​of 25%, 50%, 75% and 90%, and define them as historical typical high water year, historical typical normal water year, historical typical low water year and historical typical extremely low water year, respectively. Step S32: Based on the time series of natural daily runoff in typical historical hydrological years, calculate the average long-term guarantee rate of ecological flow under various ecological flow calculation methods. The calculation formula is: ； In the above formula, Indicates the type of a typical historical hydrological year; This represents a collection of typical historical hydrological years. ; Indicates the first Typical historical hydrological data of the year Total number of days in a month; Indicates the first Under the various ecological flow calculation methods, the first Typical historical hydrological data of the year Month The ecological flow target indicator variable is set to 1 if the daily natural runoff is not lower than the corresponding ecological flow, and 0 otherwise. Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; Step S33: Perform frequency ranking analysis on the historical long-term natural daily runoff sequence of the target river section, and select the daily runoff corresponding to the frequency values ​​of 25%, 50%, and 90%, respectively. , and ; Step S34: Using the three daily runoff volumes selected in step S33 as flow thresholds, and combining the dynamic duration and recovery interval, the natural daily runoff sequences of each historical typical hydrological year are divided into extremely low flow volumes. Low flow High-flow pulse Small flood and the Great Flood Five types; Step S35: Conduct an annual life rhythm survey of the main target fish species in the target river section, and divide it into four stages: upstream migration period, spawning and reproduction period, juvenile feeding period, and overwintering period. These are identified as four ecological window periods, and the specific start and end dates of each window period are determined. Step S36: Based on the differences in the importance of each ecological window period to the life rhythm of domestic fish and their special needs for flow events, differentiated weights are assigned. The weighted average method is used to calculate the average compliance rate of ecological flow under different ecological flow calculation methods during the ecological window periods of each historical typical hydrological year. The calculation formula is: ； In the above formula, , , and They represent the first time. Under the various ecological flow calculation methods, the first The ecological flow compliance rate during the upstream intrusion period, spawning and reproduction period, juvenile feeding period, and overwintering period of typical historical hydrological data within the year. , , and These are the compliance weighting coefficients for the corresponding window periods. , , and Satisfies the weight normalization constraint; Step S37: From the historical natural monthly average runoff sequence of the target river section generated in Step S1, extract the month with the smallest natural monthly average runoff and its corresponding monthly runoff for each year to form the historical dryest natural monthly average runoff sequence, and perform frequency analysis on it to determine the frequency value of the dryest month ecological flow obtained by each ecological flow calculation method in the frequency analysis results. Based on this, the guarantee coefficient for the target frequency of ecological flow in the driest month is calculated. The calculation formula is: ； In the above formula, This represents the target frequency value of ecological flow in the driest month of the target river channel.

5. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 4, characterized in that, The formula for calculating the ecological flow compliance rate for each ecological window period in step S36 is as follows: The first The compliance rate of ecological flow during the upstream period of typical historical hydrological events within the year The calculation formula is: ； In the above formula, Indicates the first Under the various ecological flow calculation methods, the first The first typical historical hydrological year during the upstream period Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological runoff, and if it also falls under an extremely low flow event... The value is 1 if it also belongs to a low-traffic event. The value is 0.5 if the condition is met, otherwise it is 0. This represents the retrospective period. The moon; Indicates the upstream period of the target domestic fish The set of months included; In the first Typical historical hydrological upstream period within the year No. Total number of days in a month; Indicates the first Typical historical hydrological upstream period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; The first Ecological flow compliance rate during the spawning and reproduction period of typical historical hydrological conditions The calculation formula is: ； In the above formula, Indicates the first Under the various ecological flow calculation methods, the first During the spawning and reproduction period of a typical historical hydrological year, the first Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological flow, and if it also falls under the category of a major flood event... The value is 1 if it also belongs to a high-flow pulse event. or minor flood events The value is 0.5 if the condition is met, otherwise it is 0. This indicates that the period is for egg-laying and reproduction. The moon; Indicates the spawning and breeding season of the target fish. The set of months included; In the first Typical historical hydrological spawning and reproduction period within the year No. Total number of days in a month; Indicates the first Typical historical hydrological spawning and reproduction period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; The first Ecological flow compliance rate during the juvenile fish feeding period in typical historical hydrological years The calculation formula is: ； In the above formula, Indicates the first Under the various ecological flow calculation methods, the first Typical hydrological data during the feeding period of juvenile fish Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological flow, and if it also falls under the category of a minor flood event... The value is 1 if it also belongs to a high-flow pulse event. or major flood event The value is 0.5 if the condition is met, otherwise it is 0. This indicates that the fish are in the feeding stage of juvenile fish. The moon; Indicates the feeding period of the target juvenile fish. The set of months included; In the first Typical hydrological data for juvenile fish feeding period within the year No. Total number of days in a month; Indicates the first Typical hydrological data for juvenile fish feeding period within the year Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow; The first Ecological flow compliance rate during the wintering period of typical historical hydrological conditions The calculation formula is: ； In the above formula, Indicates the first Under the various ecological flow calculation methods, the first The first typical historical hydrological year during the wintering period Month The ecological flow rate of a day is an indicator variable. The value is determined using a three-day sliding window: when the natural runoff over the three days is not lower than the corresponding month's ecological runoff, and if it also falls under a low-flow event... The value is 1 if it also belongs to an extremely low traffic event. The value is 0.5 if the condition is met, otherwise it is 0. This indicates that it belongs to the overwintering period. The moon; Indicates the overwintering period of the target domestic fish. The set of months included; In the first Typical historical hydrological overwintering period No. Total number of days in a month; Indicates the first Typical historical hydrological overwintering period Total number of days; Indicates the first Typical historical hydrological data of the year Month Natural runoff per day; For the first The first ecological flow calculation method determined by the method Monthly ecological flow.

6. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 5, characterized in that, The calculation process for the habitat flow compliance index in step S4 is as follows: Step S41: Based on the traffic event classification criteria in step S34, determine the type of traffic event to which the monthly ecological traffic calculated by each method belongs, and calculate the ratio of the number of days of each type of traffic event to the total number of days in each ecological window period of the target fish. Step S42: Combining the life rhythm of the target fish with the response requirements of special flow processes in each ecological window period, construct continuous suitability functions for each ecological window period and calculate the habitat suitability for each window period. Step S43: Based on the differences in the importance of each ecological window period to the life rhythm of domestic fish, assign differentiated weights, and then use a weighted summation method to calculate the habitat flow compliance index for the entire life cycle corresponding to different ecological flow calculation methods. The calculation formula is: ； In the above formula, , , and They represent the first time. The habitat suitability of ecological flow obtained under various ecological flow calculation methods during the upstream migration period, spawning and reproduction period, juvenile foraging period, and overwintering period. , , and These are the appropriate weighting coefficients for the corresponding window periods. , , and It satisfies the weight normalization constraint.

7. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 6, characterized in that, The construction process of the continuous suitability function for each ecological window period mentioned in step S42 is as follows: During the upstream migration period, the target fish prefer low-velocity environments. Extremely low flow rates and low-flow events are conducive to upstream migration, while high flow rates generated by high-flow pulses and flood events hinder upstream migration. Based on this, appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the upstream migration period is constructed as follows: ； In the above formula, Indicates the first The habitat suitability of ecological flows obtained under various ecological flow calculation methods during the upstream period; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the upstream period obtained by various ecological flow calculation methods to the total number of days in that window period; In the constructed upstream continuous fitness function, positive values ​​of the weight coefficients represent favorable migration events, while negative values ​​of the fitness weight coefficients represent unfavorable migration events. During the spawning and breeding season, the target fish require flood pulse stimulation to spawn, preferring high-flow pulses and flood events, and disliking extremely low-flow events. Furthermore, the larger the flood magnitude, the stronger the stimulus. Based on this, appropriate weighting coefficients are configured for each flow event, and a continuous suitability function for the spawning and breeding season is constructed as follows: ； In the above formula, Indicates the first The habitat suitability during the spawning and reproduction period based on the ecological flow calculated using various ecological flow calculation methods; , , and They represent the first time. The ratio of the number of days with extremely low flow, low flow, high flow pulses and flood events during the spawning and reproduction period to the total number of days in the window period, obtained under various ecological flow calculation methods; The overall contribution value of the flood pulse; For the first The ratio of the number of days in a major flood event to the total number of days in the spawning and reproduction window, wherein the flood events include minor flood events and major flood events; flood events are classified into four recurrence period levels. ,Right now These represent flood levels of less than once a year, once every 1-2 years, once every 2-5 years, and once every 5 years or more, respectively, and their corresponding ecological stimulus weights. The values ​​were set to 0.3, 0.6, 0.8, and 1.0 respectively. In the constructed continuous suitability function for the spawning and reproduction period, positive values ​​of the weight coefficients represent favorable spawning and reproduction events, while negative values ​​of the suitability weight coefficients represent events that hinder spawning and reproduction. During the feeding period of juvenile fish, the target domestic fish prefer a medium flow velocity environment. High flow pulses and minor floods are conducive to food aggregation and diffusion, while extremely low flow events and major floods are unfavorable to juvenile fish activity and feeding. Based on this, appropriate weight coefficients are configured for each flow event, and a continuous suitability function for the feeding period of juvenile fish is constructed as follows: ； In the above formula, Indicates the first The habitat suitability of ecological flow obtained under various ecological flow calculation methods during the feeding period of juvenile fish; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the juvenile fish feeding period to the total number of days in the window period, obtained under various ecological flow calculation methods. In the constructed continuous suitability function for the feeding period of juvenile fish, positive values ​​of the weight coefficients represent favorable food aggregation and diffusion events, while negative values ​​of the suitability weight coefficients represent events that hinder juvenile fish activity and feeding. The target fish species require stable flow and high water depth during the overwintering period. Low flow events are conducive to maintaining a stable overwintering environment, while high flow pulses and flood events will disrupt the stability of the overwintering habitat. Based on this, appropriate weight coefficients are configured for each flow event, and a continuous suitability function for the overwintering period is constructed as follows: ； In the above formula, Indicates the first The habitat suitability during the overwintering period based on the ecological flow calculated using various ecological flow methods; , , , and They represent the first The ratio of the number of days with extremely low flow, low flow, high flow pulse, minor flood, and major flood events during the wintering period to the total number of days in the window period, obtained under various ecological flow calculation methods. In the constructed continuous suitability function for the overwintering period, positive values ​​of the weight coefficients represent environmental events that are conducive to maintaining the overwintering habitat, while negative values ​​of the suitability weight coefficients represent environmental events that disrupt the overwintering habitat.

8. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 7, characterized in that, The calculation process for the habitat status index in step S5 is as follows: Step S51: Based on the target fish ecological window period divided in step S35, the assessment period of the traditional Tennant method is adjusted to the upstream period, spawning and reproduction period, juvenile feeding period and overwintering period. Step S52: Based on the specific ecological flow and water depth requirements of the target fish during each ecological window period, set the lower limit of the base flow standard according to the differences in the window period: During the upstream migration period, the basic water depth should be guaranteed while taking into account the flow conditions to meet the migration needs; during the spawning and reproduction period, a high water level environment should be created to ensure the suspended development of drifting fish eggs; during the feeding period of juvenile fish, a medium water depth should be maintained to maintain the habitat of prey organisms; during the overwintering period, a deep water environment should be maintained to improve the water body's heat preservation capacity and stabilize the overwintering habitat. Step S53: Construct a piecewise continuous membership scoring function, using the percentage of ecological flow value in the corresponding month of each window period to the multi-year average natural flow as the independent variable. This is directly mapped to obtain the continuous habitat status score for each month. The mathematical expression of the continuous membership function is: ； In the above formula, Indicates the first The habitat status of each month's ecological flow, obtained under various ecological flow calculation methods, is continuously scored within the corresponding ecological window period. This is the lower limit of the baseflow standard corresponding to the ecological window period; Step S54: Calculate the average habitat status score for the corresponding month within each window period, then take the arithmetic mean of the average scores for the four window periods, and define it as the habitat status index of this ecological flow calculation method. .

9. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 8, characterized in that, The construction process of the adaptive comprehensive evaluation model based on the hierarchical ecological flow calculation method in step S6 is as follows: Step S61: Calculate the average deviation index. Average directional convergence index and average morphological similarity index Normalization , , Subsequently, the indicators were integrated into a hydrological rhythm adaptation layer, and the weights of each indicator were determined using an objective weighting method. , , The comprehensive score for hydrological rhythm adaptation was calculated using the weighted summation method. The calculation formula is: ； Step S62: Calculate the long-term guarantee rate. Ecological window period weighted compliance rate The guarantee coefficient for the target frequency of ecological flow in the driest month Normalization , , Subsequently, these were integrated into ecological water demand protection layer indicators, and the weights of each indicator were determined using an objective weighting method. , , The comprehensive score for ecological water demand protection was calculated using the weighted summation method. The calculation formula is: ； Step S63: Calculate the habitat flow compliance index. and habitat status index Normalization , Subsequently, the indicators were integrated into a habitat suitability layer index, and the weights of each indicator were determined using an objective weighting method. , The comprehensive score of habitat suitability was calculated using the weighted summation method. The calculation formula is: ； Step S64: Based on the sensitivity of the target river section to hydrological rhythms and the goals of ecological protection and management, set the screening thresholds for the hydrological rhythm adaptation layer. Screening thresholds for ecological water demand protection layers ; Step S65: Based on the criteria of hierarchical screening of hydrological rhythm adaptation and ecological water demand guarantee, and comprehensive scoring and ranking of habitat suitability layers, construct a comprehensive assessment model for the adaptability of ecological flow calculation methods. This involves first screening the hydrological rhythm adaptation layers, and if... If it proceeds to the next screening layer, it will be eliminated; otherwise, the ecological water demand protection layer screening will be performed. Those that make it to the final habitat suitability layer will be selected based on a comprehensive score and ranking; otherwise, they will be eliminated.

10. The adaptability assessment method for an ecological flow calculation method based on aquatic habitat coupling according to claim 9, characterized in that, In step S7, if there is only one method that passes both the hydrological rhythm adaptation layer screening and the ecological water demand guarantee layer screening, then that method is directly determined as the optimal method; if no method passes both layers of screening, then feedback is provided to adjust or relax the screening thresholds and re-evaluate.

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