A comprehensive assessment method for ecological impact of water conservancy planning and construction

Abstract

The present invention relates to the field of hydrological model construction and ecological impact assessment, and specifically discloses a comprehensive ecological impact assessment method for water conservancy planning and construction. The method includes: analyzing historical precipitation data in the planning area to provide a basis for subsequent precipitation level classification; classifying historical precipitation data according to different precipitation amounts to obtain different precipitation levels; calculating and determining the standard value of tributary runoff under different precipitation levels; dynamically adjusting the tributary level division based on the standard value of tributary runoff; further adjusting the tributary division level in the hydrological model according to the impact of the upstream on the downstream, and screening the key tributaries that need to be included in the model. The method can improve the accuracy and real-time performance of ecological impact assessment in water conservancy planning and construction.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrological model construction and ecological impact assessment, and in particular to a comprehensive ecological impact assessment method for water conservancy planning and construction. Background Art

[0002] In the process of water conservancy planning and construction, ecological environmental impact assessment has always been a key link. Traditional hydrological models usually rely on static historical data and simple flow prediction models. These models often cannot accurately reflect the real hydrological dynamic changes when faced with complex precipitation scenarios and terrain features, resulting in a large deviation between the ecological impact assessment results and the actual situation.

[0003] In particular, when the precipitation level changes, the runoff response characteristics of the tributaries also change accordingly, and the impact of upstream tributaries on downstream will show significant differences under different precipitation scenarios. In the existing technology, there is a lack of an effective method that can dynamically adjust the model structure according to real-time precipitation data and accurately predict the response of tributaries, which may lead to the neglect of the impact of key tributaries in the planning stage of water conservancy projects, thus having an adverse impact on the ecosystem.

[0004] Therefore, there is an urgent need for a technology that can combine historical precipitation data with the actual runoff response of tributaries, accurately classify and model under different precipitation levels, and improve the adaptability and accuracy of hydrological models by dynamically adjusting the tributary level, so as to meet the needs of scientific assessment of ecological impacts in water conservancy planning and construction. Summary of the invention

[0005] In order to solve the technical problem of "how to accurately model and dynamically adjust the hydrological system of the planning area based on historical precipitation data under different precipitation levels and the runoff response of each tributary, so as to improve the accuracy and real-time performance of the ecological impact assessment of water conservancy planning and construction", the purpose of the present invention is to provide a comprehensive ecological impact assessment method for water conservancy planning and construction. The technical scheme adopted is as follows:

[0006] The present invention relates to the field of hydrological model construction and ecological impact assessment, and specifically discloses a comprehensive ecological impact assessment method for water conservancy planning and construction. The method includes: analyzing historical precipitation data in the planning area to provide a basis for subsequent precipitation level classification; classifying historical precipitation data according to different precipitation amounts to obtain different precipitation levels; calculating and determining the standard value of tributary runoff under different precipitation levels; dynamically adjusting the tributary level division based on the standard value of tributary runoff; further adjusting the tributary division level in the hydrological model according to the impact of the upstream on the downstream, and screening the key tributaries that need to be included in the model. The method can improve the accuracy and real-time performance of ecological impact assessment in water conservancy planning and construction.

[0007] A comprehensive assessment method for the ecological impact of water conservancy planning and construction, the method comprising:

[0008] Analyze historical precipitation data in the planning area to provide a basis for subsequent precipitation level classification;

[0009] The historical precipitation data are classified according to different precipitation amounts to obtain different precipitation levels;

[0010] Calculate and determine the standard value of tributary runoff under different precipitation levels;

[0011] Dynamically adjust the tributary level division based on the standard value of the tributary runoff;

[0012] According to the impact of upstream on downstream, the tributary division level in the hydrological model is further adjusted, and the key tributaries that need to be included in the model are screened.

[0013] As a preferred solution, the comprehensive ecological impact assessment method of water conservancy planning and construction also includes:

[0014] Collect historical precipitation data and runoff data of each tributary in the planning area;

[0015] By analyzing historical precipitation data and tributary runoff data, the typical runoff variation characteristics under different precipitation conditions are identified;

[0016] The identified features are classified and the classification criteria for different precipitation conditions are preliminarily determined.

[0017] As a preferred solution, the comprehensive ecological impact assessment method of water conservancy planning and construction also includes:

[0018] Based on the classification standard, the historical precipitation data are divided into several precipitation levels;

[0019] The classification criteria were further refined based on the topographic features and flow directions of each tributary, and a cluster analysis was performed on the runoff response of each tributary;

[0020] Output the classification results to determine the response characteristics of each tributary under different precipitation levels.

[0021] As a preferred solution, the comprehensive ecological impact assessment method of water conservancy planning and construction also includes:

[0022] Analyze the runoff of each tributary under no precipitation or very low precipitation levels, calculate and determine the minimum runoff standard value;

[0023] Evaluate the runoff changes of each tributary under extreme precipitation levels and calculate the standard value of saturated runoff;

[0024] Based on the standard value of minimum runoff and standard value of saturated runoff, the incremental coefficient of each tributary under different precipitation levels is calculated.

[0025] As a preferred solution, the determination of the minimum runoff standard value includes:

[0026] By performing hierarchical cluster analysis on historical runoff data, the credibility of the minimum runoff of each tributary on a specific day was calculated, and the runoff with the highest credibility was selected as the standard value of the minimum runoff.

[0027] As a preferred solution, the determination of the saturated runoff standard value includes:

[0028] By analyzing the runoff data under extreme precipitation levels, the credibility of the saturation volume is calculated, and the runoff with the highest credibility of the saturation volume is selected as the standard value of the saturated runoff volume.

[0029] As a preferred solution, the comprehensive ecological impact assessment method of water conservancy planning and construction also includes:

[0030] Based on the standard values ​​of runoff of each tributary under different precipitation levels, the dynamic hierarchical structure of tributaries is constructed;

[0031] According to the changing characteristics of runoff volume, the hierarchical relationship between tributaries is adjusted and the importance of tributaries is re-classified.

[0032] As a preferred solution, the construction of the tributary dynamic hierarchical structure includes:

[0033] Using the incremental coefficient and upstream influence coefficient, the tributaries are stratified according to their impact on the overall hydrological system, and a directed graph structure is established to represent the flow relationship between tributaries.

[0034] As a preferred solution, the comprehensive ecological impact assessment method of water conservancy planning and construction also includes:

[0035] The historical precipitation data collected in step S100 is classified using a hierarchical clustering analysis method, and the historical precipitation events are divided into different precipitation magnitudes, so as to refine the model's response simulation to each tributary under different precipitation scenarios and enhance the model's prediction accuracy.

[0036] As a preferred solution, the hydrological model is regularly updated based on the latest precipitation data to adjust the tributary hierarchy and ensure that the model can continue to reflect the current hydrological conditions.

[0037] The present invention has the following beneficial effects:

[0038] First, the present invention uses hierarchical clustering analysis of historical precipitation data to reasonably classify days with different precipitation levels, so that the hydrological model can perform more accurate simulation and prediction under the same precipitation scenario. Compared with traditional methods, the present invention can better capture the characteristics of runoff changes of each tributary due to precipitation, thereby improving the prediction accuracy of the model.

[0039] Secondly, the present invention introduces the calculation of the incremental coefficient and the upstream influence coefficient. Through complex mathematical formulas, the runoff changes of each tributary under specific precipitation conditions are closely combined with its upstream and downstream relationship, and dynamic tributary screening and hierarchical adjustment are realized through a directed graph structure. This method can reflect the comprehensive impact of upstream tributaries on downstream tributaries in real time, so that the hydrological model can be automatically optimized as the precipitation conditions change, avoiding the inefficiency and inaccuracy of traditional models in complex hydrological environments.

[0040] Finally, the dynamic update mechanism of the hydrological model proposed in this invention ensures that the model can always reflect the current hydrological conditions by regularly updating precipitation data and tributary hierarchy. Compared with traditional static models, this invention can better adapt to the dynamic changes of climate change and environmental conditions, provide more scientific and real-time ecological impact assessment, provide strong support for water conservancy planning and decision-making, and significantly improve the ecological sustainability of water conservancy projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0042] Figure 1 A flow chart of a method for comprehensive assessment of ecological impact of water conservancy planning and construction provided by an embodiment of the present invention.

[0043] Figure 2 A schematic diagram of the directed graph structure for constructing all tributaries in the planning area. DETAILED DESCRIPTION

[0044] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the ecological impact comprehensive assessment method of water conservancy planning and construction proposed by the present invention, its specific implementation method, structure, characteristics and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0045] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as understood by one of ordinary skill in the art to which this invention belongs.

[0046] The specific scheme of the comprehensive assessment method for ecological impact of water conservancy planning and construction provided by the present invention is described in detail below in conjunction with the accompanying drawings.

[0047] See also Figure 1 , which shows a flow chart of a method for comprehensive assessment of ecological impact of water conservancy planning and construction provided by an embodiment of the present invention. Specifically:

[0048] S100. Analyze historical precipitation data in the planning area to provide a basis for subsequent precipitation level classification;

[0049] S200, classifying historical precipitation data according to different precipitation amounts to obtain different precipitation levels;

[0050] S300, calculating and determining the standard value of the runoff of the tributary under different precipitation levels;

[0051] S400, dynamically adjusting the tributary level division based on the standard value of the tributary runoff;

[0052] S500. According to the impact of the upstream on the downstream, further adjust the tributary division level in the hydrological model, and screen the key tributaries that need to be included in the model.

[0053] S100: Analyze historical precipitation data in the planning area to provide a basis for subsequent precipitation level classification. Step S100 at least includes steps S110-S130:

[0054] S110. Collect historical precipitation data and runoff data of each tributary in the planning area. Specifically:

[0055] First, obtain and input the digital elevation model (DEM) data of the planning area, which comes from remote sensing mapping or existing terrain data sets. DEM data provides information on topographic undulations in the planning area and is the basis for watershed segmentation. The accuracy and integrity of the terrain data are ensured by preprocessing the DEM data, including removing noise and filling depressions.

[0056] Furthermore, the watershed tool of ArcGIS is used to perform preliminary watershed segmentation based on the preprocessed DEM data. The tool automatically identifies the natural watershed points and watershed boundaries in the terrain, and generates the main watersheds and sub-watersheds in the planning area. Specifically, the watershed tool analyzes the elevation value of each pixel, determines the direction of the water flow, and distributes it to the corresponding watershed area, thereby completing the watershed division of the entire area. In this process, the input data includes the elevation value of each pixel, the flow direction calculation parameters, and the preliminary identification criteria of the diversion point.

[0057] Furthermore, after the watershed segmentation is completed, the diversion points of the major rivers are located. The diversion points are the key locations of river branches and determine the formation and development of each tributary. By combining the DEM data and the results of the watershed tool, the location of the diversion points of each major river in the planning area is determined. The location of the diversion points is corrected by superimposing high-precision topographic maps and historical hydrological data to ensure its accuracy. The coordinates of the diversion points and their corresponding watershed ranges will be recorded in detail and used as the basic input data for subsequent analysis and model building.

[0058] S120. By analyzing historical precipitation data and tributary runoff data, typical runoff change characteristics under different precipitation conditions are identified. Specifically:

[0059] After completing step S110, the spatial location information and flow direction data of the rivers, tributaries, and diversion points in the planning area have been clarified. The data includes the precise coordinates of the starting point, end point, and diversion point of each tributary, as well as the flow direction within each river basin. The core data is input into the construction process of the hydrological map structure as the basic information of nodes and edges in the directed graph.

[0060] Furthermore, when constructing the hydrological graph structure, the nodes in the directed graph are first defined. According to the input diversion point information and the starting and ending points of each tributary, each tributary is defined as a node. The node marking is based on the geographical location and flow direction of the tributary, and each node represents a specific water flow area (tributary).

[0061] Furthermore, after the node marking is completed, the edge of the directed graph is created according to the input flow direction data. The direction of the edge is determined by the flow direction of the tributary, pointing from the upstream node to the downstream node. Exemplarily, if tributary A flows into tributary B, then in the directed graph, node A points to node B through a directed edge. At this time, it is also necessary to combine the diversion point data between the tributaries to ensure that all edges accurately reflect the true path of the water flow. The weight of the edge can be set based on the flow, length or other hydrological parameters of the tributary, and in the subsequent calculation, the impact of different tributaries can be weighted. Analysis.

[0062] Furthermore, when the nodes and edges are correctly created and connected, the generated directed graph structure is the hydrological map of the entire planning area. By visualizing the structure, the hydrological characteristics can be intuitively displayed in space. The visualized hydrological map can show the flow path of the river, the relative positions of the tributaries and their mutual relationships. In this step, the system verifies whether the connection relationship between the tributaries is consistent with the actual situation to ensure the correctness and integrity of the graph structure.

[0063] Furthermore, after the hydrological graph structure is constructed and verified, the final directed graph structure is stored in a standardized data format for subsequent calls and analysis. This graph structure includes not only the basic information of nodes and edges, but also additional hydrological parameters of each node and edge, such as tributary flow, length, catchment area, etc. The information will be used as input data for further analysis of the model to evaluate the ecological impact under different hydrological conditions in the planning area.

[0064] S130, classify the identified features and preliminarily determine the classification standards for different precipitation conditions. Specifically:

[0065] First, comprehensive data collection is conducted on the tributaries within the planning area. The data includes the length of the tributaries, the geographic coordinates of the starting and ending points, the direction of the river, and other basic data related to hydrological characteristics. The data can be obtained through a variety of means, such as remote sensing image analysis, on-site measurement, historical hydrological literature records, etc.

[0066] Furthermore, historical runoff data related to the tributaries in the planning area are collected. This data comes from long-term hydrological monitoring records, including runoff changes on daily, monthly and annual scales. The collected runoff data covers different precipitation conditions to ensure that subsequent models can cope with various hydrological scenarios. For tributaries with relatively missing data, they can be extrapolated from data in neighboring basins or estimated using meteorological data to ensure that the runoff data of each tributary is as complete and accurate as possible. After the data collection is completed, strict data verification and cleaning are carried out. The verification process includes checking the consistency of the geographic information and hydrological data of each tributary to ensure the logical consistency between the tributary length, flow direction and runoff data. Data cleaning includes operations such as removing outliers, filling data gaps, and unifying data formats.

[0067] Furthermore, the hydrological data is standardized to ensure the consistency of the model when processing data from different tributaries. The standardized data is input into the model as the basic data for model calculation. When the data enters the model, it is also matched with the geographical information and diversion point data of the tributaries to ensure that all key parameters of each tributary are accurately reflected in the model.

[0068] S200: classify historical precipitation data according to different precipitation amounts to obtain different precipitation levels. Specifically:

[0069] First, historical precipitation data and corresponding runoff data for the planning area are collected. This data covers multiple years and provides a detailed record of the impact of different precipitation events on each tributary. The data includes daily precipitation, runoff of each tributary, terrain characteristics (such as slope), etc.

[0070] Furthermore, the impact of precipitation on the above-mentioned tributaries is analyzed. Preliminary analysis: Due to the terrain characteristics (such as steep terrain upstream and gentle terrain downstream), precipitation has different effects on upstream and downstream tributaries. Specifically: Under low precipitation conditions, the increase in upstream runoff is small and has almost no impact on the downstream. Under medium precipitation conditions, the upstream runoff increases significantly, which has a certain impact on the downstream. Under high precipitation conditions, the upstream runoff reaches saturation, resulting in a significant increase in downstream runoff. Feature summary: Under different precipitation levels, the runoff changes of the above-mentioned tributaries show obvious stage characteristics: small, medium and large changes.

[0071] Furthermore, the hierarchical clustering analysis is performed. The historical precipitation data is clustered, with the goal of classifying daily precipitation events into different precipitation levels. Clustering method: A bottom-up hierarchical clustering method is adopted, and the sth tributary is taken as an example to perform cluster analysis on the runoff change data of all days. Initial cluster setting: The data of each day is regarded as an initial cluster, and clustering is performed in units of days. Distance metric: The difference in runoff is used as the distance metric, that is, the smaller the difference in runoff between two days, the more similar the precipitation events of these two days. Cluster merging: Gradually merge clusters with high similarity until the total number of clusters reaches a preset value (such as 3 clusters) and stop merging. In this way, the historical data of each tributary will be divided into three clusters representing different precipitation levels.

[0072] Further, the precipitation magnitude is determined. Unified precipitation magnitude classification: The clustering results of each tributary are compared to find the days in the same cluster. If some days belong to the same cluster in the clustering results of all tributaries, then the days can be regarded as belonging to the same precipitation magnitude. Discrete day processing: For discrete days (i.e., days that do not clearly belong to a certain cluster), they are divided into the precipitation magnitude with the most similar clusters. In this way, all days in the historical data are reasonably classified into several precipitation magnitudes.

[0073] Finally, the precipitation level classification results are output. Through the above analysis, several precipitation levels are finally obtained. The days contained in each precipitation level represent typical precipitation events under this level, and the days have similar precipitation characteristics and impacts on the runoff of each tributary. Further analysis: The classification results of the precipitation level will be used for subsequent model construction and analysis, so that the model can accurately predict and simulate future hydrological changes based on historical data under the same precipitation level.

[0074] S300, calculating and determining the standard value of the runoff of the tributary under different precipitation levels. Step S300 at least includes steps S310-S330:

[0075] S310, analyze the runoff of each tributary under no precipitation or very low precipitation levels, and calculate and determine the minimum runoff standard value. Specifically:

[0076] First, collect historical runoff data of each tributary under no precipitation or very low precipitation levels. The data covers observation records of multiple years to ensure the representativeness and stability of the data. The collected data should include the runoff of each tributary in different periods, especially in the dry season or the period of time with little precipitation. The data will be used to analyze the basic flow level of the tributary, that is, the flow naturally formed by the tributary when there is no significant precipitation input. Exemplarily, first obtain the minimum runoff standard value and the saturated runoff standard value of each tributary. The minimum runoff standard value reflects the runoff level of each tributary when there is no precipitation in the past year, and the saturated runoff reflects the runoff level when the runoff of each tributary increases to saturation.

[0077] Furthermore, the minimum runoff standard value of each tributary is calculated based on the collected historical runoff data. Specifically, for each tributary, its minimum runoff standard value during the observation period is identified, and its preliminary minimum runoff standard value is determined by statistical methods. The purpose of the step is to obtain the natural flow of each tributary under no precipitation or very low precipitation levels as a basis for subsequent analysis.

[0078] Taking the sth tributary as an example, the cluster with the smallest average runoff in the clustering results of the tributary is recorded as the smallest cluster, and the standard value of the runoff on each day in the smallest cluster is calculated as the credibility of the minimum runoff, which is recorded as the minimum credibility of the sth tributary on the tth day. :

[0079]

[0080] Among them, s represents the number of tributaries, t represents the number of days, represents the minimum credibility of the s-th tributary on the t-th day, The frequency of the runoff value of the s-th tributary on the t-th day in the smallest cluster of the s-th tributary is represented by represents the total frequency of all runoff values ​​in the smallest cluster of the sth tributary, represents the runoff of the sth tributary on the tth day, represents the average value of all runoff in the smallest cluster of the sth tributary, Prevent the denominator from being 0. The Sigmoid function represents the normalization of the data.

[0081] Indicates the frequency ratio of the runoff value on day t in the smallest cluster. The larger this item is, the higher the frequency of the runoff value on day t in this cluster is, indicating that the flow on this day is more typical under no precipitation or very little precipitation conditions. Therefore, the larger this value is, the more likely the flow on that day is to represent the basic flow of the tributary.

[0082] It is used to measure the deviation between the runoff value on day t and the average value of the standard runoff value in the smallest cluster of the tributary. If the runoff on day t is close to the average value of the smallest cluster (i.e. ≈ ), the term is close to 1; if the deviation is large (i.e. keep away ), the term becomes smaller. This means that when When it is close to the mean, the confidence is higher, indicating that this value is more representative of the base flow under no or very little precipitation conditions.

[0083] The result of multiplying the two is nonlinearly compressed by the Sigmoid function, so that the final credibility value Normalized to the interval (0,1). This process can smooth the impact of extreme values ​​and make the calculation results more robust.

[0084] The logical implication is to determine through statistical analysis whether the standard value of runoff on a certain day can represent the basic flow of the tributary under a series of low or no precipitation conditions. The typicality (i.e., frequency) of this flow value in this situation and the difference (i.e., the degree of deviation from the average) of the flow values ​​on other similar days are taken into account to calculate a reliability. This reliability can be used to assess whether the standard value of the runoff on a certain day can be used as the representative value of the minimum runoff of the tributary.

[0085] In order to ensure the accuracy of the minimum runoff standard value, a minimum credibility analysis is further performed. The credibility of the minimum runoff standard value of each tributary on a specific day is calculated by using the statistical method of the Sigmoid function. This process involves hierarchical clustering of the tributary runoff standard value data, classifying similar runoff standard value data into one category, so as to more accurately identify the time period representing the basic flow of the tributary. Credibility analysis helps to eliminate the influence of outliers or extreme weather conditions on the calculation of the minimum runoff standard value and ensure the representativeness of the standard value.

[0086] After the credibility analysis, the most representative minimum runoff standard value is selected as the standard value of the tributary. This standard value reflects the basic flow of the tributary under no precipitation or very little precipitation, and can truly represent the minimum ecological demand flow of the tributary. The determined minimum runoff standard value will be recorded and stored as the benchmark value for subsequent incremental analysis of runoff standard values. This standard value plays a key role in the subsequent hydrological model to ensure that the model can accurately simulate the response of the tributary under different precipitation conditions.

[0087] S320: Evaluate the runoff changes of each tributary under extreme precipitation levels and calculate the standard value of saturated runoff. Specifically:

[0088] First, collect data on extreme precipitation events that have occurred in the planning area in history. Extreme precipitation magnitude refers to heavy rain or rainstorm levels, which have the greatest impact on the standard value of tributary runoff. The required data include the standard value of daily runoff, precipitation intensity, duration, etc. of each tributary under the extreme precipitation conditions. The data provide a basis for analyzing the runoff response of tributaries under extreme precipitation conditions.

[0089] After obtaining the runoff data under extreme precipitation levels, a preliminary analysis of the maximum runoff standard value was performed for each tributary. The maximum runoff standard value was identified by statistically analyzing the runoff standard value of each tributary during the extreme precipitation event. The goal of this step is to determine the maximum flow of each tributary under extreme precipitation conditions in order to subsequently calculate the saturated runoff standard value.

[0090] In order to ensure the accuracy of the saturated runoff standard value, the credibility of the maximum runoff standard value was further analyzed. The statistical method used in the analysis of the minimum runoff standard value was used to calculate the credibility of the saturation of each tributary in extreme precipitation events. This process involves hierarchical clustering of the tributary runoff standard values, comparing the maximum runoff standard value reached under extreme precipitation conditions with the runoff standard values ​​under other smaller precipitation conditions to identify which runoff standard values ​​can be considered saturated. Through this analysis, the excessive influence of outliers or single extreme events on the calculation of saturated runoff standard values ​​can be ruled out.

[0091] Specifically, the minimum credibility of the s-th tributary on all days is obtained, and the standard value of runoff corresponding to the maximum credibility is taken as the minimum standard value of runoff of the s-th tributary.

[0092] The cluster with the largest average runoff standard value in the clustering results of the s-th tributary is recorded as the largest cluster. The daily runoff standard value in the largest cluster is calculated as the credibility of the saturated runoff, which is recorded as the credibility of the saturated runoff on the d-th day of the s-th tributary. :

[0093]

[0094] Where: It represents the total frequency of all values ​​greater than the runoff value of the s-th tributary on the d-th day appearing in the largest cluster of the s-th tributary. This parameter is used to measure whether the standard value of the runoff on that day is close to the maximum standard value of the runoff of the tributary under extreme precipitation conditions. It represents the runoff of the s-th tributary on the d-th day, which is the standard value of the runoff actually observed on a certain day. The minimum value of all runoffs of the sth tributary. This parameter is used as a benchmark to calculate the degree of deviation of the standard value of runoff on a certain day relative to the minimum value of all observed values ​​of the tributary. Prevent the denominator from being 0.

[0095] The smaller the value of is, the less likely it is that the runoff of the s-th tributary on the d-th day is greater than that of the s-th tributary on the d-th day, and the runoff of the s-th tributary on the d-th day is more saturated. The larger the value of is, the larger the runoff of the sth tributary on the dth day is, and the more saturated the runoff is.

[0096] This formula To calculate the runoff volume for a particular day Whether it can represent the saturated runoff state of the tributary, that is, the maximum flow that the tributary may reach under extreme precipitation conditions. The logical meaning of the calculation result is that through the formula Evaluate the credibility of the runoff on a certain day (i.e., the credibility of the saturation volume) to determine whether the flow on that day can be used as the saturation flow of the tributary.

[0097] Specifically: when A small value means the runoff volume for that day It is close to the extreme runoff standard value of the tributary, so the flow on that day is highly credible, indicating that the runoff standard value at this time is close to saturation. The value is large, and If the value is small, the standard value of runoff on that day is likely to have reached the saturation flow level of the tributary. and The credibility of the saturation volume on a certain day is calculated comprehensively, so as to judge whether the flow on that day can reflect the saturation state of the tributary under extreme precipitation conditions. Finally, by calculating the credibility of the saturation volume on all days, the standard value of the runoff on the day with the highest credibility is selected as the standard value of the saturated runoff volume of the tributary. This calculation result is an important parameter for evaluating the extreme response of the tributary in subsequent model analysis and decision-making.

[0098] S330: Based on the minimum runoff standard value and the saturated runoff standard value, calculate the incremental coefficient of each tributary under different precipitation levels. Specifically:

[0099] The calculation of the incremental coefficient is based on the previously determined minimum runoff and saturated runoff standard values. Therefore, the minimum runoff standard value and saturated runoff data of each tributary are first input into the model. The data are derived from the basic flow (minimum runoff standard value) under no precipitation or very low precipitation levels and the maximum flow (saturated runoff standard value) under extreme precipitation levels, respectively reflecting the runoff standard value boundaries of the tributary under two extreme conditions.

[0100] For each tributary, the average runoff standard value for each day is calculated using the historical runoff standard value data at different precipitation levels. The calculated average value represents the typical flow level of the tributary at a specific precipitation level. This step ensures that the results are statistically significant by analyzing the multi-day runoff standard value data at each precipitation level in the historical data. The average runoff standard value data will serve as the basis for the calculation of the increment coefficient.

[0101] The incremental coefficient of each tributary under each type of precipitation level is calculated to reflect the increase in the standard value of runoff of each tributary under each precipitation level. The calculation method is:

[0102]

[0103] Where: represents the average runoff of the sth tributary on all days under the rth precipitation level, represents the saturated runoff of the sth tributary, represents the minimum runoff of the sth tributary, represents all days within the rth precipitation level, represents the kth day within the rth precipitation level, represents the runoff of the sth tributary on the kth day under the rth precipitation level, represents the linear normalization function.

[0104] It reflects the overall runoff level of the sth tributary under the rth precipitation level. The larger the value, the represents the difference between the saturated runoff and the minimum runoff of the sth tributary, expressed as The value of is used as the weight in the calculation of the incremental coefficient of the sth tributary. The smaller the value of is, the smaller the increase in the overall runoff of the sth tributary is. When the runoff of the sth tributary increases, the greater the impact is, the greater the incremental coefficient is. When the sth tributary has no saturated runoff, The value of 2 times, then The result is , It represents the average value of the increase in runoff of the sth tributary on all days under the rth precipitation level. The larger the value, the greater the increase in runoff of the sth tributary under the rth precipitation level, and the greater the increment coefficient of the sth tributary under the rth precipitation level. When the saturated flow represented by does not exist (i.e. the tributary has not reached saturation), the formula will be Set to 2× , which indicates that even under extreme precipitation conditions, the increment coefficient of tributaries should not be too large to prevent the distortion of model prediction results.

[0105] The logical meaning of this formula is to calculate the incremental coefficient of each tributary under different precipitation levels, thereby quantifying the response intensity of the tributary to different precipitation conditions. Specifically:

[0106] Meaning of the incremental coefficient: The incremental coefficient is used to measure the increase in the standard value of the tributary's runoff relative to its basic flow under a certain precipitation level. The larger the coefficient, the more significant the increase in the standard value of the tributary's runoff relative to its basic flow under the precipitation conditions, indicating that the tributary is very sensitive to precipitation.

[0107] The overall logic of the formula: By combining the minimum runoff standard value, saturated runoff standard value and actual observed runoff standard value of the tributary, the formula comprehensively considers the flow change amplitude of the tributary under different precipitation conditions and normalizes the said change. The final incremental coefficient provides a relatively unified standard to help evaluate the response capacity of different tributaries under different precipitation scenarios.

[0108] S400: dynamically adjust the tributary level division based on the standard value of the tributary runoff. Step S400 at least includes steps S410-S420:

[0109] S410: Based on the standard values ​​of runoff of each tributary under different precipitation levels, a dynamic hierarchical structure of the tributaries is constructed. Specifically:

[0110] The calculation of the upstream impact coefficient takes into account key data such as the increment coefficient of each tributary, the length of the tributary, and the position of the tributary in the hydrological map structure. First, the increment coefficient of each tributary at different precipitation levels (already calculated by the previous submodules) is input into the model. In addition, the physical length data of the tributaries is also input, which can be obtained through geographic information system (GIS) tools. The length of the tributary determines the degree of dissipation of water when it propagates between tributaries, so it is crucial in calculating the upstream impact coefficient.

[0111] Figure 2 To construct a directed graph structure diagram of all tributaries in the planning area. Take each tributary as each vertex in the directed graph, and each upstream tributary points to the downstream tributary. The schematic diagram is as follows: the left side is a river schematic diagram, black lines represent rivers, white dots represent diversion points, and diversion points divide the river into several tributaries. The right side is a directed graph structure diagram corresponding to the river in the left figure. A vertex in the directed graph represents a tributary, and the direction of the arrow is determined by the flow direction of the river, from the upstream tributary to the downstream tributary. The upstream influence coefficient of the sth tributary under the rth precipitation level The calculation method is:

[0112]

[0113] in, represents the length of the adjacent upstream tributary of the sth tributary, represents the increment coefficient of the adjacent upstream tributary of the sth tributary under the rth precipitation level, represents the increment coefficient of the sth tributary under the rth precipitation level, represents the variance of the runoff of the sth tributary on all days under the rth precipitation level, It represents the number of edges from the corresponding vertex of the sth tributary in the directed graph to the vertex with in-degree 0, that is, the number of tributaries between the sth tributary and the most upstream tributary.

[0114] The larger the value of is, the larger the increment coefficient of the sth tributary and its adjacent upstream tributaries is. The larger the value is, the greater the increase in runoff of the sth tributary and its adjacent upstream tributaries is under the rth precipitation level. The larger the value of indicates, the greater the change in the runoff of the sth tributary under the rth precipitation level. The larger the value of is, the longer the length of the adjacent upstream tributary of the sth tributary is, and the smaller the impact on the sth tributary is. The larger the value of is, the lower the sth tributary is, and the smaller the upstream influence is. The upstream influence coefficient of the most upstream tributary is 1.

[0115] The larger the upstream influence coefficient, the greater the change in the corresponding sth tributary when the adjacent upstream of the sth tributary changes. Therefore, if there are small tributaries with large upstream influence coefficients, such small tributaries cannot be ignored when constructing the hydrological model because they will have large changes in the standard value of runoff according to changes in precipitation.

[0116] Calculated upstream impact coefficient It is used to quantify the influence of upstream tributaries on downstream tributaries under specific precipitation levels. This coefficient reflects how the change in the standard value of the runoff of the upstream tributary affects the flow change of the current tributary under the current precipitation conditions. Specifically: if A large value means that the change in the standard value of the runoff of the upstream tributary has a significant impact on the current tributary, indicating that the flow change in the upstream can be significantly transmitted to the downstream. This situation is crucial in hydrological models because it shows that the upstream tributaries cannot be ignored and should be considered in detail in the model. If the value is small, it means that the upstream tributary has limited impact on the current tributary, and the model can be appropriately simplified to reduce the computational complexity.

[0117] S420. According to the changing characteristics of runoff, adjust the hierarchical relationship between tributaries and reclassify the importance of tributaries. Specifically:

[0118] After the upstream influence coefficient is calculated, it is applied to the hydrological directed graph structure in the planning area. Each node in the directed graph represents a tributary, and the edge represents the direction and interaction of the water flow. Through the directed graph, the connection relationship between the tributaries and the conduction path of the water flow can be intuitively expressed. This information is the basis for analyzing the upstream and downstream hydrological relationship.

[0119] Under a specific precipitation level, the correlation between the upstream influence coefficient and the change in the standard value of the downstream runoff is calculated for each tributary. This process involves analyzing how the flow changes of the upstream tributaries are transmitted to the downstream tributaries through the hydrological system. Specifically, the method of correlation calculation is as follows: First, the standard value data of the runoff of each tributary under different precipitation levels and its corresponding upstream influence coefficient are obtained. Then, the correlation between the upstream influence coefficient and the change in the standard value of the downstream runoff is calculated by statistical methods, such as the Pearson correlation coefficient or other applicable regression analysis techniques. The higher the correlation coefficient, the greater the impact of the upstream flow change on the downstream flow. In addition, considering factors such as the length of the tributary, the terrain characteristics, and the position of the tributary in the directed graph, the correlation calculation results are adjusted and corrected. The adjustment helps to improve the accuracy of the analysis and ensure that the calculated correlation can truly reflect the actual hydrological process.

[0120] Furthermore, the model is verified by calculating the correlation results. The analysis results are compared with historical hydrological events to check whether the actual impact of upstream flow changes on downstream flow is consistent with the model prediction. If inconsistency or large deviation is found, it is necessary to return to adjust the upstream influence coefficient or correlation calculation method to improve the accuracy of the model.

[0121] Finally, based on the results of the upstream and downstream hydrological relationship analysis, key tributaries with greater impact on the downstream are identified. The key tributaries will receive special attention in water conservancy planning, especially when formulating scheduling and management plans. The analysis results will also be used as input data to optimize the hierarchical division of the hydrological model to ensure that the model can accurately predict flow conduction and impact under different precipitation conditions.

[0122] S500: Further adjust the tributary classification level in the hydrological model according to the impact of the upstream on the downstream, and select the key tributaries that need to be included in the model. Specifically:

[0123] First, the division weights of the tributaries are calculated. Input parameters: The increment coefficient of each tributary at a specific precipitation level and upstream impact coefficient . The incremental coefficient of each tributary is and upstream impact coefficient Multiply them to reflect the importance of the tributary to the overall hydrological model under this precipitation level. This product reflects the combined effect of the tributary's runoff changes and upstream influences. The above product is normalized to obtain a standardized partition weight. The purpose of normalization is to adjust the influence values ​​of each tributary to a unified scale, and the normalized result is usually between 0 and 1. This partition weight can be understood as the importance score of the tributary to the entire hydrological system under the current precipitation scenario.

[0124] Furthermore, a tributary effective threshold is set and key tributaries are screened. A predefined effective threshold is set, such as 0.2. This threshold is used to distinguish important tributaries from minor tributaries. According to the normalized division weights, all tributaries whose division weights are greater than the effective threshold are screened out. The tributaries are considered to have a significant impact on the hydrological dynamics under the current precipitation level, so they must be taken into account when constructing the hydrological model. On the contrary, tributaries with division weights lower than the threshold may have less impact on the overall hydrological dynamics and can be simplified or ignored.

[0125] Furthermore, a hydrological model is constructed using the selected key tributaries. This model aims to simulate the changes in hydrological resources in the planning area, including flow changes, distribution, and potential impacts on the surrounding ecosystem. By integrating the dynamic data of the important tributaries, the model can more accurately predict and observe the hydrological changes in the region. The model is updated regularly to maintain its accuracy. For example, precipitation levels may change over time, which will affect the division weights of tributaries and their importance in the model. According to the monthly or weekly precipitation data, the division weights of tributaries and the model structure are adjusted in real time to ensure that the model can continue to reflect the latest hydrological dynamics.

[0126] After the model is built, it is used to observe the changes in hydrological resources in the planning area in real time. The model's predictions are verified by comparing them with actual observation data. This step not only helps the model adapt to changing environmental conditions, but also verifies the model's accuracy. Based on the observations, the model's predictions are compared and analyzed with the actual observed hydrological data. If a deviation is found between the model prediction and the actual situation, the model parameters and structure need to be further optimized to ensure that it can predict the changes in hydrological resources more accurately.

[0127] The ecological impact of water conservancy planning and construction is evaluated using validated model results. The forecast data provided by the model can help decision makers understand the potential impact of different planning schemes on the ecosystem, thereby optimizing the design and implementation of water conservancy projects and minimizing adverse impacts on the environment. Based on the real-time observation results of the model, the planning scheme is adjusted to ensure that the water conservancy project can dynamically adapt to environmental changes during implementation and achieve the best ecological and social benefits.

[0128] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or advantageous.

[0129] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0130] The key innovations of the present invention are:

[0131] (1) Combination of incremental coefficient and upstream influence coefficient: The product of the incremental coefficient and the upstream influence coefficient is calculated and used to screen and adjust the key tributaries in the hydrological model to ensure that the model can dynamically reflect the actual hydrological changes of each tributary.

[0132] (2) Dynamic tributary screening based on directed graph structure: A directed graph structure is introduced to represent the relationship between tributaries, and the tributary hierarchy is adjusted according to real-time precipitation data, so that the hydrological model can be dynamically adjusted as environmental conditions change.

[0133] (3) Hierarchical clustering analysis of historical precipitation data: Hierarchical clustering is used to classify historical precipitation events into different precipitation magnitudes, further refining the model’s simulation of tributary responses under different precipitation scenarios and enhancing the model’s prediction accuracy.

[0134] (4) Real-time update mechanism of the hydrological model: The model is regularly adjusted according to the latest precipitation data to ensure that it always reflects the current hydrological conditions and improves the accuracy of the prediction.

[0135] The present invention has the following beneficial effects:

[0136] First, the present invention uses hierarchical clustering analysis of historical precipitation data to reasonably classify days with different precipitation levels, so that the hydrological model can perform more accurate simulation and prediction under the same precipitation scenario. Compared with traditional methods, the present invention can better capture the characteristics of runoff changes of each tributary due to precipitation, thereby improving the prediction accuracy of the model.

[0137] Secondly, the present invention introduces the calculation of the incremental coefficient and the upstream influence coefficient. Through complex mathematical formulas, the runoff changes of each tributary under specific precipitation conditions are closely combined with its upstream and downstream relationship, and dynamic tributary screening and hierarchical adjustment are realized through a directed graph structure. This method can reflect the comprehensive impact of upstream tributaries on downstream tributaries in real time, so that the hydrological model can be automatically optimized as the precipitation conditions change, avoiding the inefficiency and inaccuracy of traditional models in complex hydrological environments.

[0138] Finally, the dynamic update mechanism of the hydrological model proposed in this invention ensures that the model can always reflect the current hydrological conditions by regularly updating precipitation data and tributary hierarchy. Compared with traditional static models, this invention can better adapt to the dynamic changes of climate change and environmental conditions, provide more scientific and real-time ecological impact assessment, provide strong support for water conservancy planning and decision-making, and significantly improve the ecological sustainability of water conservancy projects.

Claims

1. A comprehensive assessment method for the ecological impact of water conservancy planning and construction, characterized in that: The method comprises: S100. Analyze historical precipitation data in the planning area to provide a basis for subsequent precipitation level classification; S200, classifying historical precipitation data according to different precipitation amounts to obtain different precipitation levels; S300, calculating and determining the standard value of the runoff of the tributary under different precipitation levels; S400, dynamically adjusting the tributary level division based on the standard value of the tributary runoff; S500, further adjusting the tributary division level in the hydrological model according to the impact of the upstream on the downstream, and screening the key tributaries that need to be included in the model; wherein the incremental coefficient of each tributary is multiplied by the upstream influence coefficient, and the product is normalized to obtain a standardized division weight, and all tributaries whose division weights are greater than the effective threshold are screened as key tributaries; Among them, the upstream impact coefficient of the sth tributary under the rth precipitation level is The calculation method is: in, represents the length of the adjacent upstream tributary of the sth tributary, represents the increment coefficient of the adjacent upstream tributary of the sth tributary under the rth precipitation level, represents the increment coefficient of the sth tributary under the rth precipitation level, represents the variance of the runoff of the sth tributary on all days under the rth precipitation level, It represents the number of edges from the corresponding vertex of the sth tributary in the directed graph to the vertex with in-degree 0, that is, the number of tributaries between the sth tributary and the most upstream tributary.

2. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 1 is characterized in that: Step S100 includes: S110. Collect historical precipitation data and runoff data of each tributary in the planning area; S120. By analyzing historical precipitation data and tributary runoff data, identify typical runoff change characteristics under different precipitation conditions; S130, classifying the identified features and preliminarily determining classification standards for different precipitation conditions.

3. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 2 is characterized in that: Step S200 includes: Based on the classification standard in step S130, the historical precipitation data is classified into a number of precipitation levels; The classification criteria were further refined based on the topographic features and flow directions of each tributary, and a cluster analysis was performed on the runoff response of each tributary; Output the classification results to determine the response characteristics of each tributary under different precipitation levels.

4. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 1 is characterized in that: Step S300 includes: S310, analyzing the runoff of each tributary under no precipitation or very low precipitation levels, and calculating and determining the minimum runoff standard value; S320, evaluate the runoff change of each tributary under extreme precipitation levels and calculate the standard value of saturated runoff; S330. Based on the minimum runoff standard value and the saturated runoff standard value, calculate the incremental coefficient of each tributary under different precipitation levels.

5. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 4 is characterized in that: The determination of the minimum runoff standard value in step S310 includes: By performing hierarchical cluster analysis on historical runoff data, the credibility of the minimum runoff of each tributary on a specific day was calculated, and the runoff with the highest credibility was selected as the standard value of the minimum runoff.

6. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 4 is characterized in that: The determination of the saturated runoff standard value in step S320 includes: By analyzing the runoff data under extreme precipitation levels, the credibility of the saturation volume is calculated, and the runoff with the highest credibility of the saturation volume is selected as the standard value of the saturated runoff volume.

7. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 1 is characterized in that: Step S400 includes: S410, constructing a dynamic hierarchical structure of tributaries based on the standard values ​​of runoff of each tributary under different precipitation levels; S420. Adjust the hierarchical relationship between tributaries according to the changing characteristics of runoff volume and reclassify the importance of tributaries.

8. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 7 is characterized in that: The construction of the tributary dynamic hierarchical structure in step S410 includes: Using the incremental coefficient and upstream influence coefficient, the tributaries are stratified according to their impact on the overall hydrological system, and a directed graph structure is established to represent the flow relationship between tributaries.

9. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 1 is characterized in that: The method further comprises: The historical precipitation data collected in step S100 is classified using a hierarchical clustering analysis method, and the historical precipitation events are divided into different precipitation magnitudes, so as to refine the model's response simulation to each tributary under different precipitation scenarios and enhance the model's prediction accuracy.

10. The method for comprehensive assessment of ecological impact of water conservancy planning and construction according to claim 9 is characterized in that: The hydrological model is regularly updated based on the latest precipitation data to adjust the tributary hierarchy and ensure that the model continues to reflect current hydrological conditions.

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