Fish ecological flow assessment method based on habitat simulation method and related device

Abstract

The invention discloses a fish ecological flow assessment method based on a habitat simulation method and a related device, and relates to the technical field of environmental scientificity, and the method comprises the steps: obtaining the relative multi-degree, flow velocity distribution diagram and water depth distribution diagram of each fish in a target drainage basin; constructing an ecological suitability curve based on the suitability curve index; calculating a weighted available area WUA value under a typical working condition through a River 2D model physical habitat module; according to the water depth distribution diagram and the flow velocity distribution diagram, based on the ecological suitability curve, the flow of the fish in the spawning period is calculated; according to the weighted available area WUA value and the flow, a habitat weighted available area-flow relation curve is constructed, the monthly satisfaction degree and the monthly deviation rate of the ecological flow of the target drainage basin are calculated, and a comprehensive index is calculated through a geometric mean value formula; and evaluating the health level of the target drainage basin according to the comprehensive index. According to the method, the suitable ecological flow of the fishes in the river and the health level of the drainage basin can be evaluated more accurately.

Description

Technical Field

[0001] The present application relates to the field of environmental science and technology, and in particular to a fish ecological flow assessment method based on habitat simulation and related devices. Background Art

[0002] Ecological flow is essential for maintaining the health of river ecosystems, ensuring the sustainable use of water resources, and protecting aquatic organisms. However, due to the differences in the economic and social development levels of river basins and regions and the temporal and spatial differences in different seasons (such as flood season, normal water season, and dry season), it is difficult to formulate unified ecosystem protection and restoration standards for different river basins, regions, and various water conservancy projects, as well as unified environmental impact assessment and planning environmental impact assessment criteria for water conservancy and hydropower projects. Therefore, how to evaluate ecological flow has become one of the key issues to be solved in the field of river basin management. Although some progress has been made in ensuring ecological flow, the current ecological flow assessment methods for different rivers still have defects and shortcomings. Summary of the invention

[0003] The purpose of this application is to provide a fish ecological flow assessment method and related devices based on habitat simulation method, which can more accurately assess the suitable ecological flow of fish in rivers.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In the first aspect, the present application provides a fish ecological flow assessment method based on habitat simulation method, comprising:

[0006] Obtain the relative abundance, velocity distribution map and water depth distribution map of each fish species in the target watershed; the relative abundance is calculated based on the total number of fish caught and the number of sampled fish caught within a set time; the water depth distribution map and the velocity distribution map are obtained by using the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of water depth and water flow velocity in the river under typical operating flow conditions in the target watershed;

[0007] According to the relative abundance of each fish species, water flow velocity and water depth, an ecological suitability curve is constructed based on the suitability curve index; the suitability curve index is an indicator of the survival suitability of each fish species under different water flow velocity and water depth conditions;

[0008] Based on the survival suitability index, the weighted available area (WUA) value of the target watershed under typical conditions is calculated through the physical habitat module of the River 2D model;

[0009] Calculate the flow rate during the spawning period of fish based on the water depth distribution map and flow velocity distribution map of the target watershed and the ecological suitability curve;

[0010] Construct a habitat weighted available area - flow relationship curve based on the weighted available area (WUA) value of the target river basin and the flow during the fish spawning period; use the flow corresponding to the inflection point of the curve as the ecological flow of the target river basin for the habitat weighted available area - flow relationship curve.

[0011] Calculate the monthly satisfaction degree and monthly deviation rate of the ecological flow of the target river basin, and calculate the comprehensive index through the geometric mean formula.

[0012] Evaluate the health level of the target river basin according to the comprehensive index.

[0013] Optionally, the calculation formula for the monthly satisfaction degree of the ecological flow of the target river basin is:

[0014]

[0015] where D i is the satisfaction degree of the ecological flow in the i-th month; P is the number of days in the total evaluation period; p is the number of days that meet the ecological flow in the total evaluation period N.

[0016] Optionally, the calculation formula for the monthly deviation rate of the ecological flow of the target river basin is:

[0017]

[0018] where C i is the monthly flow deviation rate; Q ei is the ecological flow value calculated in the i-th month; Q i is the median of the measured monthly average flow sequence in the i-th month.

[0019] Optionally, the calculation formula for the comprehensive index is:

[0020]

[0021] where Z i is the comprehensive index.

[0022] Optionally, evaluating the health level of the target river basin according to the comprehensive index specifically includes:

[0023] When 0.8 < Z i ≤ 1, the health level of the target river basin is excellent;

[0024] When 0.6 < Z i ≤ 0.8, the health level of the target river basin is good;

[0025] When 0.4 < Z i ≤ 0.6, the health level of the target river basin is medium;

[0026] When 0.2 < Z iWhen it is ≤ 0.4, the health level of the target basin is poor;

[0027] When 0 ≤ Z i ≤ 0.2, the health level of the target basin is extremely poor.

[0028] Optionally, the calculation formula for the relative abundance of each fish is:

[0029]

[0030] Wherein, RD is the relative abundance of a certain specified fish; N is the total number of caught fish; n is the number of caught fish sampled for the target fish.

[0031] In a second aspect, the present application provides a fish ecological flow evaluation device based on a habitat simulation method, including:

[0032] An information acquisition module, configured to acquire the relative abundance of each fish, the flow velocity distribution map, and the water depth distribution map in the target basin; the relative abundance is calculated according to the total number of caught fish and the number of caught fish sampled for the target fish within a set time; the water depth distribution map and the flow velocity distribution map are obtained by using the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of the water depth in the river channel and the spatial distribution characteristics of the water flow velocity under the typical working condition flow of the target basin respectively;

[0033] An ecological suitability curve construction module, configured to construct an ecological suitability curve based on the relative abundance of each fish, the water flow velocity, and the water depth, based on the suitability curve index; the suitability curve index is the survival suitability index of each fish under different water flow velocity and water depth conditions;

[0034] A WUA value calculation module, configured to calculate the weighted available area WUA value of the target basin under typical working conditions through the physical habitat module of the River 2D model based on the survival suitability index;

[0035] A flow calculation module, configured to calculate the flow during the fish spawning period based on the water depth distribution map and the flow velocity distribution map of the target basin, based on the ecological suitability curve;

[0036] A habitat weighted available area - flow relationship curve construction module, configured to construct a habitat weighted available area - flow relationship curve according to the weighted available area WUA value of the target basin and the flow during the fish spawning period; the habitat weighted available area - flow relationship curve takes the flow corresponding to the inflection point of the curve as the ecological flow of the target basin;

[0037] A comprehensive index calculation module, configured to calculate the monthly satisfaction degree and the monthly deviation rate of the ecological flow of the target basin, and calculate the comprehensive index through the geometric mean formula;

[0038] An evaluation module for evaluating the health level of a target river basin according to comprehensive indicators.

[0039] In a third aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement a fish ecological flow evaluation method based on a habitat simulation method as described in any one of the above.

[0040] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements a fish ecological flow evaluation method based on a habitat simulation method as described in any one of the above.

[0041] In a fifth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements a fish ecological flow evaluation method based on a habitat simulation method as described in any one of the above.

[0042] According to the specific embodiments provided by the present application, the following technical effects are disclosed in the present application:

[0043] The present application provides a method and related device for evaluating fish ecological flow based on the habitat simulation method. First, by obtaining the relative abundance of each fish species, the flow velocity distribution map, and the water depth distribution map in the target watershed, the distribution of fish and the water flow environment in the target watershed can be comprehensively understood. The calculation of relative abundance takes into account the total number of catches within a set time and the number of sampled catches of the target fish species, ensuring the accuracy and representativeness of the data. At the same time, the two-dimensional hydrodynamic module of the River 2D model is used to simulate the spatial distribution characteristics of water depth and water flow velocity under typical working conditions of the target watershed, providing detailed water flow environment data. Secondly, based on the relative abundance of each fish species, water flow velocity, and water depth, combined with the suitability curve index, an ecological suitability curve is constructed. This step takes into account the survival suitability of fish under different water flow conditions, thus being able to more accurately reflect the adaptation of fish to the water flow environment. Then, the weighted available area (WUA) value of the target watershed under typical working conditions is calculated through the physical habitat module of the River 2D model, further quantifying the living space of fish in the target watershed. This step takes into account the available habitat area of fish under different water flow conditions, providing a basis for evaluating ecological flow. Next, according to the water depth distribution map and flow velocity distribution map of the target watershed, combined with the ecological suitability curve, the flow rate during the fish spawning period is calculated. This step takes into account the special requirements of fish for the water flow environment during the spawning period, thus being able to more accurately evaluate the survival status of fish during the spawning period. Subsequently, based on the weighted available area (WUA) value of the target watershed and the flow rate during the fish spawning period, a relationship curve between the habitat weighted available area and the flow rate is constructed. This step determines the ecological flow of the target watershed through the flow rate corresponding to the inflection point of the curve, providing a scientific basis for formulating reasonable water resource management strategies. Finally, the monthly satisfaction and monthly deviation rate of the ecological flow of the target watershed are calculated, and the comprehensive index is calculated through the geometric mean formula. This step takes into account the satisfaction of ecological flow in different months, thus being able to more comprehensively evaluate the health level of the target watershed. According to the comprehensive index, the health status of the target watershed can be accurately quantified and evaluated. Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 It is an application environment diagram of a method for evaluating fish ecological flow based on the habitat simulation method in an embodiment of the present application;

[0046] Figure 2Schematic flowchart of a fish ecological flow assessment method based on a habitat simulation method provided by an embodiment of the present application;

[0047] Figure 3 Habitat suitability curve graph of an indicative fish for a protection target provided by an embodiment of the present application;

[0048] Figure 4 For a 30m 3 Water depth distribution map at a flow rate of / s;

[0049] Figure 5 For a 30m 3 Flow velocity distribution map at a flow rate of / s;

[0050] Figure 6 Relationship curve graph between habitat weighted available area and flow rate change provided by an embodiment of the present application;

[0051] Figure 7 Comprehensive index curve graph of the annual target ecological flow at Station A in the target basin provided by an embodiment of the present application;

[0052] Figure 8 Schematic diagram of functional modules of a fish ecological flow assessment device based on a habitat simulation method provided by an embodiment of the present application;

[0053] Figure 9 Schematic diagram of the structure of a computer device provided by an embodiment of the present application. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0055] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0056] The fish ecological flow assessment method based on the habitat simulation method provided by the embodiments of the present application can be applied to, for example Figure 1In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set separately, integrated on the server 104, placed on the cloud or other servers. The terminal 102 can send the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin to the server 104. After receiving the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin, for the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin, the server 104 constructs an ecological suitability curve based on the relative abundance of each fish, water flow velocity, and water depth, and based on the suitability curve index; the suitability curve index is the survival suitability index of each fish under different water flow velocity and water depth conditions; based on the survival suitability index, the weighted available area (WUA) value of the target basin under typical working conditions is calculated through the physical habitat module of the River 2D model; according to the water depth distribution map and flow velocity distribution map of the target basin, based on the ecological suitability curve, the flow rate during the fish spawning period is calculated; according to the weighted available area (WUA) value of the target basin and the flow rate during the fish spawning period, a relationship curve of habitat weighted available area - flow rate is constructed; the relationship curve of habitat weighted available area - flow rate uses the flow rate corresponding to the inflection point of the curve as the ecological flow rate of the target basin; the monthly satisfaction degree and monthly deviation rate of the ecological flow rate of the target basin are calculated, and the comprehensive index is calculated through the geometric mean formula; the health level of the target basin is evaluated according to the comprehensive index. The server 104 can feedback the obtained health level of the target basin to the terminal 102. In addition, in some embodiments, the fish ecological flow rate evaluation method based on the habitat simulation method can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly process the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin, or the server 104 can obtain the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin from the data storage system and process the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin.

[0057] Among them, the terminal 102 can be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0058] In an exemplary embodiment, such as Figure 2As shown, a method for evaluating the ecological flow of fish based on the habitat simulation method is provided. This method is executed by a computer device, specifically, it can be executed alone by a computer device such as a terminal or a server, or jointly executed by a terminal and a server. In the embodiments of the present application, taking the method applied to Figure 1 server 104 in [reference] as an example for illustration, it includes the following steps 201 to 207. Among them:

[0059] Step 201: Obtain the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin; the relative abundance is calculated based on the total number of catches and the number of sampled catches of the target fish within a set time; the water depth distribution map and the flow velocity distribution map are obtained by using the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of the water depth and the water flow velocity in the river channel under the typical working condition flow of the target basin respectively;

[0060] Step 202: Based on the relative abundance, water flow velocity, and water depth of each fish, construct an ecological suitability curve based on the suitability curve index; the suitability curve index is the survival suitability index of each fish under different water flow velocity and water depth conditions;

[0061] Step 203: Based on the survival suitability index, calculate the weighted available area (WUA) value of the target basin under typical working conditions through the physical habitat module of the River 2D model;

[0062] Step 204: Based on the ecological suitability curve, calculate the flow rate during the spawning period of fish according to the water depth distribution map and the flow velocity distribution map of the target basin;

[0063] Step 205: Based on the weighted available area (WUA) value of the target basin and the flow rate during the spawning period of fish, construct a relationship curve between the habitat weighted available area and the flow rate; the flow rate corresponding to the inflection point of the curve of the relationship curve between the habitat weighted available area and the flow rate is used as the ecological flow rate of the target basin;

[0064] Step 206: Calculate the monthly satisfaction degree and the monthly deviation rate of the ecological flow rate of the target basin, and calculate the comprehensive index through the geometric mean formula;

[0065] Step 207: Evaluate the health level of the target basin according to the comprehensive index.

[0066] Among them, in an exemplary embodiment, when executing step 201, specifically, it can be as follows:

[0067] Based on the data analysis method of fish relative abundance, select indicative species.

[0068] Its specific calculation formula is as follows:

[0069]

[0070] In the formula: RD is the relative abundance of a certain specified fish, %; N is the total number of caught fish, tails; n is the number of sampled caught fish of a certain specified fish, tails.

[0071] According to the fish sampling survey results of the middle and lower reaches of the target watershed by Ding Yang et al. in 2015: A total of 10,166 fish samples were collected, mainly belonging to 5 orders, 15 families, 57 genera, and a total of 74 species. The relative abundance of fish can be calculated according to formula (1). Cypriniformes accounted for the largest proportion of the total sampling, 67.57%; Perciformes accounted for 16.22% of the total; Siluriformes accounted for 10.81% of the total; Cyprinodontiformes accounted for 1.35% of the total; Synbranchiformes accounted for 4.05% of the total.

[0072] The middle and lower reaches of the target watershed (section A to B) is a natural spawning fish river course, with good spawning conditions, diverse water ecological environments, excellent water quality physical and chemical factors, and relatively superior hydrological conditions; among Cypriniformes in the river section, economic fish represented by the "Four Major Domestic Fishes" (black carp Mylopharyngodon piceus, grass carp Ctenopharyngodon idellus, silver carp Hypophthalmichthys molitrix, and bighead carp Aristichys nobilis) are widely distributed and relatively suitable for spawning here. With the development of tourism and the reduction of suitable habitats for fish to survive, the species and quantity of fish in the target watershed are decreasing, and the biodiversity of fish in the river course is in jeopardy; the overall quantity of the "Four Major Domestic Fishes" shows a downward and decreasing trend. Therefore, the typical representatives of economic fish, the "Four Major Domestic Fishes", are selected as the protected target fish of the indicator species.

[0073] Among them, the two-dimensional hydrodynamic module of the River 2D model simulates the spatial distribution characteristics of water depth and the spatial distribution characteristics of flow velocity in the river course under 8 typical working condition flows.

[0074] The hydrodynamic module of the River 2D model is based on the Saint-Venant equation of two-dimensional average water depth, and the main principle includes three control equations: mass conservation, momentum conservation in the x-plane coordinate direction, and momentum conservation in the y direction:

[0075] q x = HU (5).

[0076] q y = HV (6).

[0077] In the formula: H is the water depth, m; U and V are the average flow velocities in the x and y directions respectively, m / s; q x and q yThe partial flow rates on the x and y coordinate axes are m 2 / s; S ix and S iy are the riverbed slopes in the x and y directions respectively; S fx and S fy are the friction resistance slopes in the x and y directions respectively; τ xx , τ xy , τ yx and τ yy are the partial tensor components of the shear stress in each horizontal direction, N / m 2 .

[0078] According to the classification criteria of different evaluation levels of the Tennant method during the fish spawning period: when the multi-year average monthly average flow rate is lower than 40% of the multi-year average annual flow rate, the multi-year average monthly average flow rate is taken as the ecological flow rate; when the multi-year average monthly average flow rate is between 40% and 100% of the multi-year average annual flow rate, 40% of the multi-year average annual flow rate is taken as the ecological flow rate; when the multi-year average monthly average flow rate is higher than the multi-year average annual flow rate, 40% of the multi-year average monthly average flow rate is taken as the ecological flow rate.

[0079] Therefore, in this application, flow rate values of 10%, 30%, 40%, 50%, 60% and 100% (29.1, 87.1, 116.1, 145.1, 174.1 and 290.2 m3 / s) under the multi-year average runoff conditions during the fish spawning period are respectively selected as the flow input conditions for 6 different working conditions of the upstream boundary of the model simulation analysis, and in addition, the one-way navigation standard flow rate of 30 m 3 / s and the two-way navigation standard flow rate of 60 m 3 / s for these 2 working conditions are added.

[0080] Use the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of the water depth and the spatial distribution characteristics of the flow velocity in the river under the flow rates of the above 8 typical working conditions respectively, and obtain the corresponding water depth distribution map and flow velocity distribution map ( Figures 4 - 5 , only some of the result maps are shown).

[0081] Among them, in an exemplary embodiment, when performing step 202, it can be specifically as follows:

[0082] In this embodiment, the critical values of the suitable water depth and flow velocity condition parameters are set such that the suitability curve index HSI = 0, and the most suitable range of the parameter HSI value is set to HSI = 1 ( Figure 3 ). The larger the HSI suitability index, the more suitable the hydraulic parameter conditions are for the survival of the specified protected target fish species.

[0083] Specifically, considering the overall characteristics of the four selected economic fish species in this embodiment, the optimal spawning period for the "Four Major Chinese Carps" is from April to July when there is a flood peak in the target river basin. The average body length of the "Four Major Chinese Carps" is usually between 0.2 m and 0.5 m, and they are all drift-spawning fish species. When the flow velocity is less than 0.2 m / s, the drift eggs start to sink due to insufficient flow velocity. Referring to the standard of "Design Guidelines for Fish Passes of Water Conservancy and Hydropower Projects" (SL 609-2013), the suitable flow velocity range is approximately 0.2 m / s to 1.9 m / s. The flow velocity range that simultaneously meets the preferences of the four economic fish species is approximately 0.6 m / s to 0.8 m / s. According to the standard of "Calculation Specification for Ecological Flow of Hydropower Projects" (NB / T 35091-2016), the most suitable water depth for fish is 2 to 3 times the body length. Therefore, in this application, the most suitable water depth is taken as 0.4 m to 1.5 m. Since the influence of water depth on fish spawning and growth conditions is relatively small, and at the same time, to meet the conditions for migration, spawning, rearing, and adult fish habitat, the water depth in this embodiment is set with a value range of 0.2 m to 5 m as the suitable condition. In this embodiment, the river channel substrate is not the dominant influencing factor for the habitat and spawning of the target indicator fish species. Therefore, the river channel substrate is generalized to have a suitability index of 1.

[0084] Among them, in an exemplary embodiment, when performing steps 203-205, it can be specifically as follows:

[0085] The physical habitat component module of the River 2D model is based on the concept of Weighted Usable Area (WUA), which is derived from the Physical Habitat Simulation System (PHABSIM). The WUA value is a composite function calculated for each node and its associated "sub-basin" in the study area, that is, the product of the Habitat Suitability Index (HSI, ranging from 0.0 to 1.0). In the River 2D model, a node refers to the calculation point of the finite element grid, and the sub-basin area corresponds to the area of the "Thiessen polygon", which covers the adjacent area of this point.

[0086] The River 2D model is one of the two-dimensional models for simulating instream habitats in the IFIM method (Instream Flow Incremental Methodology). The IFIM method believes that water depth, flow velocity, substrate, and cover are the key factors affecting the species number and distribution due to flow changes. Through investigation and analysis, the suitability requirements of indicator species for environmental factors such as water depth and flow velocity are determined, and the suitability curves between environmental parameters (such as water depth and flow velocity) and preference levels (expressed as values between 0 and 1) are drawn. Furthermore, the weighted usable area (WUA) of indicator species is calculated, and the specific calculation method for determining the combined suitability of habitats is as follows using the comprehensive impact factor formula:

[0087]

[0088] CSF i = V i D i C i (8).

[0089] In the formula: WUA is the weighted usable area of the indicator species, m 2 ; CSF(V i , D i , C i ) is the combined suitability value of the i-th impact factor; D i is the water depth suitability index of the i-th unit; V i is the flow velocity suitability index of the i-th unit; C i is the river substrate suitability index of the i-th unit; A is the horizontal area of the i-th unit, m 2 .

[0090] Among them, according to the two-dimensional hydrodynamic simulation results of the study reach of the target basin under different working condition flows, by inputting the flow velocity, water depth suitability files of the four major Chinese carps and the river substrate index file, the weighted usable area (WUA) values of habitats are simulated and calculated using the physical habitat module under different working condition flows during the fish spawning period (flow values of 10%, 30%, 40%, 50%, 60%, and 100% of the multi-year average runoff during the fish spawning period, as well as the one-way navigation standard flow of 30 m3 / s and the two-way navigation standard flow of 60 m 3 / s).

[0091] Based on the calculated weighted usable area of habitats (WUA value) and flow, a relationship curve of weighted usable area of habitats - flow is drawn (such as Figure 6As shown, observe the change of the weighted available habitat area (WUA) value shown by the curve with the rise and fall of the ecological flow. Find the turning point of the weighted available habitat area-flow relationship curve at the maximum value of the weighted available habitat area (WUA). The flow value corresponding to the inflection point is the most suitable sensitive ecological flow.

[0092] In this embodiment, 145.1 m 3 / s (the flow value under the condition that the fish spawning period accounts for 50% of the multi-year average runoff) is determined as the sensitive ecological flow value during the fish spawning period, which can maximize the survival environmental conditions of the "Four Major Chinese Carps" in the river channel of the target basin and more effectively protect the indicator species, and further maintain the rich situation of fish resources and the health of the river ecosystem in the target basin water system protection target. Therefore, this embodiment takes 145.1 m3 / s as the most suitable sensitive ecological flow value for the protection target during the fish spawning period.

[0093] Among them, in an exemplary embodiment, when performing steps 206-207, specifically as follows:

[0094] The geometric mean method is used to comprehensively organize the monthly deviation rate and monthly satisfaction index of the ecological flow into a comprehensive index as a reference for the previously calculated ecological flow value.

[0095] The monthly satisfaction of the ecological flow is an important measurement index for maintaining the river ecosystem and also an important scientific support for river ecological regulation. The satisfaction of the ecological flow is generally reflected by the historical water inflow guarantee rate. The satisfaction guarantee rate of the ecological flow refers to the ratio of the series length of the flow in the river channel that can meet the ecological water demand to the total series length within a certain period. The specific calculation formula of its guarantee rate is as follows:

[0096]

[0097] Among them, D i is the ecological flow satisfaction in the i-th month; P is the number of days in the total evaluation period; p is the number of days that meet the ecological flow in the total evaluation period N.

[0098] The ratio D i The larger it is, the higher the ecological flow satisfaction. The closer its value is to 1, the more the natural flow can meet the demand of the river ecological flow, and the healthier the river ecosystem is during this period.

[0099] The monthly deviation rate of the ecological flow refers to the ratio of the calculated ecological flow value to the median of the measured monthly average flow sequence. This index can reflect the deviation degree between the ecological flow and the measured flow. Its specific calculation formula is:

[0100]

[0101] Among them, C iis the monthly flow deviation rate, %; Q ei is the ecological flow value calculated for the i-th month, m 3 / s; Q i is the median of the measured monthly average flow sequence for the i-th month, m 3 / s. C i The closer the C value is to 1, the closer the calculated ecological flow is to the natural flow.

[0102] The monthly satisfaction degree of ecological flow and the monthly ecological flow deviation rate index depict the relationship between ecological flow and actual flow from different perspectives. Considering the two indicators comprehensively can more accurately reflect the relationship between natural flow and ecological flow. Therefore, the geometric mean method is used to comprehensively calculate the two indicators as the comprehensive index of ecological flow, and its calculation formula is:

[0103]

[0104] where Z i is the comprehensive index, and the closer the Z i value is to 1, the closer the ecological flow is to the actual flow, that is, the more the actual flow can meet the requirements of ecological flow, which means the healthier the river ecosystem is. Therefore, according to the Z i value, the river health status can be divided into five levels: 0.8 < Z i ≤1 is excellent, 0.6 < Z i ≤0.8 is good, 0.4 < Z i ≤0.6 is medium, 0.2 < Z i ≤0.4 is poor, 0 ≤ Z i ≤0.2 is extremely poor.

[0105] In addition, in an exemplary embodiment, after performing step 207, it further includes: determining the target ecological flow suitable for the target watershed based on the habitat simulation method and the hydrological method, and then evaluating whether the target ecological flow of the target watershed meets the standard of a healthy river according to the comprehensive index.

[0106] Specifically, referring to the annual monthly basic ecological flow values of the typical control section of Station A in the target watershed calculated by the hydrological method, and combining with the sensitive ecological flow during the fish spawning period determined by the habitat simulation method research, it can be found that the ecological flow values determined by the habitat simulation method are greater than the results of the basic ecological flow calculated by the hydrological method in most months during the fish spawning period. And considering that the flow required during the fish spawning period is large, sufficient flow is needed for pulses, and the sensitive ecological flow during the fish spawning period determined by the habitat simulation method is more targeted for protecting the target indicator species "four major Chinese carps", so the sensitive ecological flow determined by the habitat simulation method is selected as the ecological flow value during this period.

[0107] This application believes that the monthly basic ecological flow values calculated by the Texas method are also optimal in terms of water demand at both the annual and general water use periods. The Texas method uses long-term monthly runoff data, takes into account the seasonal variation factors of the river, and takes the monthly average flow value corresponding to the 50% guarantee rate at a specific percentage as the ecological flow. In this application, a specific percentage of 40% is taken according to the characteristics of the target basin. Therefore, for the basic ecological flow value of Station A in the general water use period of the target basin, it is recommended in this application to use the calculation results of the Texas method, and in combination with the determination of the sensitive ecological flow value during the fish spawning period by the habitat simulation method, further propose the annual monthly target ecological flow values for the typical control section of Station A in the target basin (Table 1).

[0108] Table 1 Annual Target Ecological Flow Values of Station A in the Target Basin

[0109]

[0110] Table 2 Annual Target Ecological Flow Deviation Rate and Satisfaction Degree of Station A in the Target Basin

[0111]

[0112] Table 3 Annual Target Ecological Flow Comprehensive Index Evaluation Values of Station A in the Target Basin

[0113] January February March April May June July August September October November December 0.56 0.49 0.55 0.58 0.63 0.62 0.55 0.56 0.56 0.58 0.48 0.54 Medium Medium Medium Medium Good Good Medium Medium Medium Medium Medium Medium

[0114] Among them, Figure 7 Table 2 and Table 3 respectively show the annual target ecological flow comprehensive indexes of Station A in the target basin and their evaluation grades. From the perspective of satisfaction degree, the satisfaction degrees from August to December are relatively high, all above 0.9; the satisfaction degrees from February to March and from May to June are relatively low, all below 0.8. From the perspective of deviation rate, the deviation rate from May to June is above 0.5, the deviation rate in April is 0.42, and the deviation rates in other months are all below 0.4. From the perspective of the comprehensive index evaluation value, only the ecological flow comprehensive index value from May to June is above 0.6, and the evaluation grade is "good"; the values in the remaining months are all in the range of 0.5 - 0.6, and the evaluation grades are all medium.

[0115] Based on the same inventive concept, the embodiment of this application also provides a fish ecological flow evaluation device for implementing the above-mentioned fish ecological flow evaluation method based on the habitat simulation method. The implementation solutions provided by this device to solve problems are similar to the implementation solutions recorded in the above method. Therefore, the specific limitations in one or more of the following processing device embodiments can refer to the limitations on the fish ecological flow evaluation method based on the habitat simulation method in the above text, and will not be elaborated here.

[0116] In an exemplary embodiment, as Figure 8As shown, a fish ecological flow evaluation device based on a habitat simulation method is provided, including:

[0117] An information acquisition module 801, configured to acquire the relative abundance, flow velocity distribution map, and water depth distribution map of each fish in the target basin; the relative abundance is calculated based on the total number of catches and the number of sampled catches of the target fish within a set time; the water depth distribution map and the flow velocity distribution map are obtained by using the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of the water depth and the water flow velocity in the river channel under the typical working condition flow of the target basin respectively;

[0118] An ecological suitability curve construction module 802, configured to construct an ecological suitability curve based on the relative abundance, water flow velocity, and water depth of each fish, based on the suitability curve index; the suitability curve index is the survival suitability index of each fish under different water flow velocity and water depth conditions;

[0119] A WUA value calculation module 803, configured to calculate the weighted available area (WUA) value of the target basin under typical working conditions through the physical habitat module of the River 2D model based on the survival suitability index;

[0120] A flow calculation module 804, configured to calculate the flow during the fish spawning period based on the water depth distribution map and the flow velocity distribution map of the target basin, based on the ecological suitability curve;

[0121] A habitat weighted available area-flow relationship curve construction module 805, configured to construct a habitat weighted available area-flow relationship curve based on the weighted available area (WUA) value of the target basin and the flow during the fish spawning period; the flow corresponding to the inflection point of the habitat weighted available area-flow relationship curve is used as the ecological flow of the target basin;

[0122] A comprehensive index calculation module 806, configured to calculate the monthly satisfaction degree and the monthly deviation rate of the ecological flow of the target basin, and calculate the comprehensive index through the geometric mean formula;

[0123] An evaluation module 807, configured to evaluate the health level of the target basin according to the comprehensive index.

[0124] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 9As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store processed data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a method for evaluating the ecological flow of fish based on the habitat simulation method.

[0125] Those skilled in the art can understand that Figure 9 the structure shown in the figure is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0126] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in the above method embodiments are implemented.

[0127] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0128] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by the processor, the steps in the above method embodiments are implemented.

[0129] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0130] Those of ordinary skill in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0131] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logic devices based on quantum computing, etc., without limitation.

[0132] In summary, the present application has the following technical effects:

[0133] 1) The present application uses the habitat simulation method to construct the spatial distribution characteristics of water depth and flow velocity in the river channel based on a two-dimensional hydrodynamic model, and uses a physical habitat model to calculate and draw the relationship curve of available habitat area - discharge based on the habitat suitability index curve, so as to analyze and obtain the ecological flow for the indicative aquatic species to inhabit during the sensitive period in the typical river section of the target basin. Then, based on this flow rate, the monthly deviation rate and monthly satisfaction index of the ecological flow rate are comprehensively sorted into a comprehensive index for reference. In this way, the obtained ecological flow rate can more accurately reflect the relationship between natural flow rate and ecological flow rate and conform to the actual situation than a single evaluation.

[0134] 2) In this application, during the evaluation process of the target ecological flow suitability, the ecological flow values determined by the comparative habitat simulation method in most months of the fish spawning period are compared with the basic ecological flow values calculated by the hydrological method. Considering the flow required during the fish spawning period and the need for sufficient flow for pulses, it makes up for the problems of the hydrological method, which has low requirements for data and simple calculations but ignores the influence between biological parameters and flow, and the hydraulic method, which is not applicable to rivers with large seasonal variations and lacks consideration of biological parameters. Moreover, the sensitive ecological flow during the fish spawning period determined by the habitat simulation method is more targeted for protecting the target indicator species, the "four major Chinese carps".

[0135] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0136] Specific examples are used in this article to elaborate on the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, based on the idea of this application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A fish ecological flow assessment method based on habitat simulation method, characterized in that: include: Obtain the relative abundance, flow velocity distribution map and water depth distribution map of each fish species in the target watershed; The relative abundance is calculated based on the total number of fish caught and the number of sampled fish caught within a set time; the water depth distribution map and the flow velocity distribution map are obtained by using the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of water depth and water flow velocity in the river under typical operating flow conditions in the target basin; According to the relative abundance of each fish species, water flow velocity and water depth, an ecological suitability curve is constructed based on the suitability curve index; the suitability curve index is an indicator of the survival suitability of each fish species under different water flow velocity and water depth conditions; Based on the survival suitability index, the weighted available area (WUA) value of the target watershed under typical conditions is calculated through the physical habitat module of the River 2D model; Calculate the flow rate during the spawning period of fish based on the water depth distribution map and flow velocity distribution map of the target watershed and the ecological suitability curve; According to the WUA value of the target watershed and the flow rate during the spawning period of fish, a habitat weighted available area-flow relationship curve is constructed; The habitat weighted available area-flow relationship curve uses the flow corresponding to the curve inflection point as the ecological flow of the target watershed; Calculate the monthly satisfaction and monthly deviation rate of ecological flow in the target watershed, and calculate the comprehensive index through the geometric mean formula; Assess the health level of the target watershed based on comprehensive indicators.

2. The fish ecological flow assessment method based on habitat simulation method according to claim 1 is characterized in that: The calculation formula for the monthly satisfaction of ecological flow in the target watershed is: Among them, D i is the ecological flow satisfaction of the i-th month; P is the number of days in the total evaluation period; p is the number of days that meet the ecological flow in the total evaluation period N.

3. The fish ecological flow assessment method based on habitat simulation method according to claim 1 is characterized in that: The calculation formula for the monthly deviation rate of ecological flow in the target watershed is: Among them, C i is the monthly flow deviation rate; Q ei is the ecological flow value calculated in the i-th month; Q i is the median of the measured monthly average flow series in the ith month.

4. The fish ecological flow assessment method based on habitat simulation method according to claim 1 is characterized in that: The calculation formula of the comprehensive index is: Among them, Z i It is a comprehensive indicator.

5. The fish ecological flow assessment method based on habitat simulation method according to claim 4 is characterized in that: The health level of the target watershed is assessed based on comprehensive indicators, including: When 0.8<Z i When ≤1, the health level of the target watershed is excellent; When 0.6<Z i When ≤0.8, the health level of the target watershed is good; When 0.4<Z i When ≤0.6, the health level of the target watershed is moderate; When 0.2<Z i When ≤0.4, the health level of the target watershed is poor; When 0≤Z i When ≤0.2, the health level of the target watershed is extremely poor.

6. The fish ecological flow assessment method based on habitat simulation method according to claim 1 is characterized in that: The calculation formula for the relative abundance of each fish species is: Among them, RD is the relative abundance of a certain specified fish; N is the total number of catches; and n is the number of sampled catches of the target fish.

7. A fish ecological flow assessment device based on habitat simulation method, characterized in that: include: An information acquisition module is used to obtain the relative abundance, flow velocity distribution map and water depth distribution map of each fish species in the target watershed; The relative abundance is calculated based on the total number of fish caught and the number of sampled fish caught within a set time; the water depth distribution map and the flow velocity distribution map are obtained by using the two-dimensional hydrodynamic module of the River 2D model to simulate the spatial distribution characteristics of water depth and water flow velocity in the river under typical operating flow conditions in the target basin; The ecological suitability curve construction module is used to construct an ecological suitability curve based on the suitability curve index according to the relative abundance of each fish species, water flow velocity and water depth; the suitability curve index is an indicator of the survival suitability of each fish species under different water flow velocity and water depth conditions; The WUA value calculation module is used to calculate the WUA value of the target watershed weighted available area under typical conditions through the physical habitat module of the River 2D model based on the survival suitability index; A flow calculation module, used to calculate the flow during the fish spawning period according to the water depth distribution map and flow velocity distribution map of the target watershed and based on the ecological suitability curve; A habitat weighted available area-flow relationship curve construction module is used to construct a habitat weighted available area-flow relationship curve according to the weighted available area WUA value of the target watershed and the flow rate during the fish spawning period; The habitat weighted available area-flow relationship curve uses the flow corresponding to the curve inflection point as the ecological flow of the target watershed; The comprehensive index calculation module is used to calculate the monthly satisfaction and monthly deviation rate of the ecological flow of the target watershed, and calculate the comprehensive index through the geometric mean formula; The evaluation module is used to evaluate the health level of the target watershed based on comprehensive indicators.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a fish ecological flow assessment method based on habitat simulation as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements a fish ecological flow assessment method based on habitat simulation method as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, it implements a fish ecological flow assessment method based on habitat simulation method as described in any one of claims 1-6.

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