A method for regulating the rising and falling water process during the breeding period of fish that lay drifting eggs

Abstract

The present invention proposes a method for regulating the rising and falling water process during the breeding period of fish that lay drifting eggs. On the basis of the existing technology for regulating the rising water process during the spawning period, an optimization idea of ​​ecological scheduling of "artificial flood peaks" in different time periods and processes is proposed. Through the correlation analysis between the monitoring data of fish eggs and the water temperature during the scheduling period, the timing of different ecological scheduling and the indicative water temperature are clarified; the rising water process is divided into two stages of rising water as a whole, with the goals of stimulating fish migration and stimulating spawning respectively, and the key indicators such as initial flow, average daily flow increase, and rising water duration are further refined through comprehensive habitat evaluation and natural rising water analysis; at the same time, the receding water process is constrained by maintaining the safe drifting and hatching of fish eggs, and the receding water process is determined based on the analysis of natural hydrological processes, forming a reservoir discharge flow plan for the entire process of "migration-spawning-egg hatching" for fish that lay drifting eggs.

Description

Technical Field

[0001] The invention relates to the technical field of water rise and fall regulation for fish reproduction, and in particular to a method for regulating water rise and fall during the reproduction period of fish that lay drifting eggs. Background Art

[0002] With the rapid development of social economy, human society's interference with rivers has increased day by day. The construction of reservoirs and hydropower stations has changed the original connectivity of rivers, causing changes in the hydraulic and hydrological conditions of the upstream and downstream rivers, and has also affected the reproduction and life of native fish in the rivers. For the river sections where water conservancy projects have been built, the following problems are generally encountered when carrying out regulation and control for fish reproduction needs:

[0003] First, artificial flood peaks during the spawning period are applied to the ecological regulation practice of the Three Gorges and Jinxia cascade reservoirs. However, at this stage, little consideration is given to the water retreat process after the flood. The rapid drop in water level after the flood will affect the hatching of fish eggs. Second, research is conducted on the migration period, spawning period, and fish egg drift, and ecological flow targets and ecological regulation plans are formulated separately. The regulation targets at each stage conflict and cannot be well connected. At the same time, separate regulation increases the loss of power generation benefits. Summary of the invention

[0004] In order to solve the problem of how to comprehensively consider the ecological flow requirements of the migration period, spawning period, and egg hatching period of fish laying drifting eggs, and set a refined "artificial flood peak" process close to the fish breeding needs, the present invention provides a method for regulating the rising and falling water process during the breeding period of fish laying drifting eggs, comprising the following steps:

[0005] S1. Divide different ecological scheduling processes and indicate water temperature according to the spawning amount and water temperature monitoring data;

[0006] S2. When the water temperature in the spawning ground reaches the indicated water temperature, the discharge of the upstream reservoir is increased to start the first stage of water rise. This stage is mainly to stimulate fish migration. The reservoir discharge is the minimum flow rate Q during the migration period. 洄 , duration d 洄 ;

[0007] S3. After the migratory stimulation is completed, the second stage of water rise begins. This stage is mainly to stimulate fish spawning. The reservoir discharge gradually increases, increasing by ΔQ every day. 涨 , duration d 涨 , Q 峰 As peak flow;

[0008] S4. After the flooding process is over, a high flow rate Q must be maintained to keep the fish eggs drifting safely. 漂 , duration d 漂 ;

[0009] S5. During the water withdrawal process, according to the analysis of natural hydrological processes, set the daily water withdrawal amplitude ΔQ 退 , duration d 退 ;

[0010] S6. Form a refined control plan for the water rise and fall process in different time periods and processes, including the reservoir discharge flow and duration at each stage.

[0011] In a preferred embodiment of the present invention, the method for determining the ecological scheduling process and the indicated water temperature in S1 specifically includes: collecting daily spawning volume and water temperature monitoring data of drifting eggs; using multiple regression analysis to clarify the impact mode and threshold of water temperature on spawning scale; determining different ecological scheduling opportunities based on the water temperature threshold, and clarifying the key fish to be protected in each scheduling process.

[0012] In a preferred embodiment of the present invention, the minimum flow rate Q in the migratory period in S2 is 洄 The specific method for determining Q includes: constructing a hydrodynamic model; simulating the distribution of potential channels for fish migration under different flow rates; and determining the minimum flow rate Q that effectively stimulates fish reproductive migration based on the relationship between the distance of the potential migration channel and the flow rate. 洄 ; Determine the duration of the migration process d based on the simulation results 洄 .

[0013] Furthermore, the construction of the hydrodynamic model is as follows: the hydrodynamic model is constructed using MIKE 21, and the roughness coefficient and viscosity coefficient are verified. The fish migration trajectory discrimination formula is coupled into the hydrodynamic model through the biological behavior simulation module. The discrimination statement is as follows:

[0014] Speed: IF(HDspeed>=HDmin), THEN 0.5, ELSEHDspeed

[0015] Direction: IF(HDspeed>=HDmin), THENHDdir+180°, ELSE HDdir

[0016] Where: Direction is the swimming direction of fish, Speed ​​is the swimming speed of fish, HDspeed is the water flow velocity, HDdir is the water flow direction, and HDmin is the minimum migration stimulation flow velocity.

[0017] In a preferred embodiment of the present invention, the daily water rise amplitude ΔQ in S3 涨 and duration of flooding d 涨The specific determination methods include: analyzing the spawning data and the measured flow data of the same period to determine the minimum standard of the flood process that can stimulate fish spawning, including the total water level increase standard and the daily flow increase standard; analyzing the natural flow and water level process to clarify the natural change state and threshold of the flow, water level and flood duration during each flood process under natural conditions;

[0018] Peak flow Q 峰 According to the evaluation of fish spawning habitat suitability, the flow corresponding to 80% of the maximum suitable habitat area is used as the flood range, that is, Q 初 ~Q 峰 , where Q 初 As the initial flow rate of flooding, Q 峰 as peak flow.

[0019] Furthermore, the evaluation of fish spawning habitat suitability specifically includes: analysis of fish habitat preferences at different spawning periods, construction of habitat suitability curves for water depth and flow velocity; use of hydrodynamic models to analyze the effective habitat area under different flow rates; establishment of a fitting curve of the relationship between the effective habitat area and flow rate, and determination of the suitable ecological flow range.

[0020] In a preferred embodiment of the present invention, the flow rate Q of maintaining the safe drift of fish eggs in S4 is 漂 The specific method for determining the flow rate Q includes: simulating the drifting trajectory of fish eggs under different flow rates based on the hydrodynamic model and the fish egg drifting model, and determining the appropriate flow rate Q that can maintain the drifting of fish eggs, taking the duration d drift of more than 50% of the fish eggs as the standard. 漂 .

[0021] Furthermore, the duration of fish egg drifting in S4 is d 漂 The specific method for determining the duration of the drifting and hatching of fish eggs includes: collecting the drifting and hatching time of key protected fish species in each period; analyzing the correlation between the drifting and hatching time of fish eggs and water temperature, and determining the duration of the drifting and hatching of fish eggs based on the confidence interval. 漂 .

[0022] In a preferred embodiment of the present invention, the daily water withdrawal amplitude ΔQ in S5 退 and duration d 退 The specific method for determining the water level is as follows: analyzing the water level fluctuation within 7 days under natural conditions as the standard for daily water level fluctuation; setting the daily water level decline amplitude ΔQ according to the water level-discharge relationship curve. 退 ; Determine the duration of water withdrawal d based on the daily flow drop and the flow before water rise 退 .

[0023] In a preferred embodiment of the present invention, the fine control scheme of the water rise and water retreat process in S6 by time period and process includes: time period refers to determining different ecological scheduling periods according to the spawning water temperature, and each scheduling period corresponds to different fish needs; process refers to the water rise process being divided into two stages and the water retreat process being divided into two stages, wherein the first stage of the water rise process is mainly to stimulate fish migration, and the reservoir discharge flow is not less than Q 洄 , duration d 洄 The second stage of the flooding process is mainly to stimulate fish spawning, and the reservoir discharge gradually increases to Q 峰 , the daily increase in traffic is no less than ΔQ 涨 , the duration is not less than d 涨 ; In the first stage of the water withdrawal process, the reservoir discharge flow is not less than Q 漂 , the number of days to be maintained is not less than d 漂 In the second stage of the water withdrawal process, the reservoir discharge gradually changes from Q 漂 Reduce to the flow rate before flooding, and the daily flow rate decrease shall not be less than d 退 .

[0024] The implementation of the present invention has the following beneficial effects:

[0025] The method for regulating the rising and falling water processes during the breeding period of fishes that lay drifting eggs of the present invention comprehensively considers the hydrological needs of the entire process of "migration-spawning-egg hatching" of fishes that lay drifting eggs, comprehensively considers stimulating fish migration and spawning during the rising water process, and takes maintaining the safe drifting and hatching of fish eggs as a constraint during the receding water process, thereby forming a refined reservoir discharge flow plan that is more in line with the physiological habits of natural reproduction of fishes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be 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 these drawings without paying creative work.

[0027] Figure 1 A schematic flow chart of a method for regulating the rising and falling water process during the breeding period of fish that lay drifting eggs provided by the present invention;

[0028] Figure 2 for the correlation between spawning size and water temperature;

[0029] Figure 3 This is a simulation diagram of fish migration in the river section of the downstream protection area of ​​Xiangjiaba;

[0030] Figure 4 This is a graph showing the success rate of upstream migration at each section under different discharge rates of Xiangjiaba;

[0031] Figure 5 This is a map showing the changes in the suitable habitat area for spawning of fish species that prefer different spawning water temperatures below Xiangjiaba Dam;

[0032] Figure 6 The duration of flooding and the water level rise required to effectively stimulate fish spawning;

[0033] Figure 7 This is a chart showing the changes in indicators of the natural flooding process in the lower reaches of the Jinsha River from April to May;

[0034] Figure 8 This is a chart showing changes in indicators of natural flooding in the lower reaches of the Jinsha River from June to July;

[0035] Fig. 9 This is the natural water level variation chart of Huadan Station and Pingshan Station within 7 days. DETAILED DESCRIPTION

[0036] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] See also Figure 1 , Figure 1 A schematic flow chart of a method for regulating the rising and falling water process during the breeding period of fish that lay drifting eggs provided by the present invention.

[0038] The present invention provides a method for regulating the rising and falling water process of fishes laying drifting eggs during the breeding period, comprising the following steps:

[0039] S1. Divide different ecological scheduling processes and indicate water temperature according to the spawning amount and water temperature monitoring data;

[0040] The specific methods for determining the ecological scheduling process and indicative water temperature include: collecting daily spawning volume and water temperature monitoring data of drifting eggs; using multiple regression analysis to clarify the impact mode and threshold of water temperature on spawning scale; determining different ecological scheduling opportunities based on water temperature thresholds, and clarifying the key fish to be protected in each scheduling process.

[0041] S2. When the water temperature in the spawning ground reaches the indicated water temperature, the discharge of the upstream reservoir is increased to start the first stage of water rise. This stage is mainly to stimulate fish migration. The reservoir discharge is the minimum flow rate Q during the migration period. 洄 , duration d 洄 ;

[0042] Minimum flow rate Q during migration period 洄The specific method for determining Q includes: constructing a hydrodynamic model; simulating the distribution of potential channels for fish migration under different flow rates; and determining the minimum flow rate Q that effectively stimulates fish reproductive migration based on the relationship between the distance of the potential migration channel and the flow rate. 洄 ; Determine the duration of the migration process d based on the simulation results 洄 .

[0043] Furthermore, the construction of the hydrodynamic model is as follows: the hydrodynamic model is constructed using MIKE 21, and the roughness coefficient and viscosity coefficient are verified. The fish migration trajectory discrimination formula is coupled into the hydrodynamic model through the biological behavior simulation module. The discrimination statement is as follows:

[0044] Speed: IF(HDspeed>=HDmin), THEN 0.5, ELSEHDspeed

[0045] Direction: IF(HDspeed>=HDmin), THENHDdir+180°, ELSE HDdir

[0046] Where: Direction is the swimming direction of fish, Speed ​​is the swimming speed of fish, HDspeed is the water flow velocity, HDdir is the water flow direction, and HDmin is the minimum migration stimulation flow velocity.

[0047] S3. After the migratory stimulation is completed, the second stage of water rise begins. This stage is mainly to stimulate fish spawning. The reservoir discharge gradually increases, increasing by ΔQ every day. 涨 , duration d 涨 , Q 峰 As peak flow;

[0048] Daily water rise ΔQ 涨 and duration of flooding d 涨 The specific determination methods include: analyzing the spawning data and the measured flow data of the same period to determine the minimum standard of the flood process that can stimulate fish spawning, including the total water level increase standard and the daily flow increase standard; analyzing the natural flow and water level process to clarify the natural change state and threshold of the flow, water level and flood duration during each flood process under natural conditions;

[0049] Peak flow Q 峰 According to the evaluation of fish spawning habitat suitability, the flow corresponding to 80% of the maximum suitable habitat area is used as the flood range, that is, Q 初 ~Q 峰 , where Q 初 As the initial flow rate of flooding, Q 峰 as peak flow.

[0050] The evaluation of fish spawning habitat suitability specifically includes: analyzing fish habitat preferences at different spawning periods, constructing habitat suitability curves for water depth and flow velocity; using hydrodynamic models to analyze the effective habitat area under different flow rates; establishing a fitting curve of the relationship between the effective habitat area and flow rate, and determining the suitable ecological flow range.

[0051] S4. After the flooding process is over, a high flow rate Q must be maintained to keep the fish eggs drifting safely. 漂 , duration d 漂 ;

[0052] Flow rate Q to maintain safe drift of fish eggs 漂 The specific method for determining the flow rate Q includes: simulating the drifting trajectory of fish eggs under different flow rates based on the hydrodynamic model and the fish egg drifting model, and determining the appropriate flow rate Q that can maintain the drifting of fish eggs, taking the duration d drift of more than 50% of the fish eggs as the standard. 漂 .

[0053] Drifting duration of fish eggs 漂 The specific method for determining the duration of the drifting and hatching of fish eggs includes: collecting the drifting and hatching time of key protected fish species in each period; analyzing the correlation between the drifting and hatching time of fish eggs and water temperature, and determining the duration of the drifting and hatching of fish eggs based on the confidence interval. 漂 .

[0054] S5. During the water withdrawal process, according to the analysis of natural hydrological processes, set the daily water withdrawal amplitude ΔQ 退 , duration d 退 ;

[0055] Daily water withdrawal amplitude ΔQ 退 and duration d 退 The specific method for determining the water level is as follows: analyzing the water level fluctuation within 7 days under natural conditions as the standard for daily water level fluctuation; setting the daily water level decline amplitude ΔQ during the water level decline period according to the water level-discharge relationship curve. 退 ; Determine the duration of water withdrawal d based on the daily flow drop and the flow before water rise 退 .

[0056] S6. Form a refined control plan for the water rise and fall process in different time periods and processes, including the reservoir discharge flow and duration at each stage;

[0057] The fine-grained control scheme of the flooding-recession process in different time periods and processes includes: time periods refer to different ecological dispatching periods determined according to the spawning water temperature, and each dispatching period corresponds to different fish needs; process division refers to the flooding process being divided into two stages and the retreating process being divided into two stages. The first stage of the flooding process is mainly to stimulate fish migration, and the reservoir discharge flow is not less than Q 洄 , duration d 洄 The second stage of the flooding process is mainly to stimulate fish spawning, and the reservoir discharge gradually increases to Q峰 , the daily increase in traffic is no less than ΔQ 涨 , the duration is not less than d 涨 ; In the first stage of the water withdrawal process, the reservoir discharge flow is not less than Q 漂 , the number of days to be maintained is not less than d 漂 In the second stage of the water withdrawal process, the reservoir discharge gradually changes from Q 漂 Reduce to the flow rate before flooding, and the daily flow rate decrease shall not be less than d 退 . Specific embodiments

[0059] 1. Division of ecological scheduling process:

[0060] Based on the daily water temperature and drifting egg monitoring data during the "artificial flood peak" ecological regulation of the cascade reservoirs in the upper reaches of the Yangtze River from 2021 to 2023, through linear regression and one-way analysis of variance, please see Figure 2 , Figure 2 The correlation between spawning scale and water temperature was studied. It was found that when the water temperature was below 21.5℃, the spawning scale of fish that lay drifting eggs was significantly positively correlated with the water temperature; when the water temperature exceeded 21.5℃, the change in water temperature had no significant effect on the spawning scale of fish that lay drifting eggs. This shows that for spawning fish (such as the "four major carps") during this period (late May to late June), although the critical water temperature for spawning is around 18℃, the spawning scale is greatly affected by water temperature at 18-21℃. After exceeding 21℃, the spawning scale is no longer restricted by water temperature. Therefore, it can be considered that the water temperature during the peak spawning period of fish that prefer high temperature spawning is 21-22℃, and the ecological scheduling effect is best at this time.

[0061] In addition, according to the ecological scheduling experiment and spawning fish monitoring statistics in the lower reaches of the Jinsha River, the monitoring volume of fish eggs such as round-mouthed copper fish and long-finned goby with relatively low spawning water temperatures during the scheduling period was very small. Therefore, for fish that mostly spawn below 20°C, targeted ecological scheduling is still needed. According to the experiment on the synergistic influence of water temperature and flow rate on fish migration, in the water temperature range of 14-18°C, increasing the flow rate can effectively stimulate the reproductive migration behavior of fish that lay drifting eggs, and the suitable water temperature for spawning of fish that lay drifting eggs in the lower reaches of the Jinsha River is mainly between 16-25°C. Therefore, when the water temperature reaches 16-18°C, it is suitable to carry out ecological scheduling for spawning fish that prefer to spawn at low temperatures. The ecological scheduling for drifting egg-laying fish at different times is shown in Table 1:

[0062] Table 1 Fish species that lay drifting eggs in different water temperature ranges during the peak spawning period

[0063]

[0064] 2. Determine the first stage of flood flow based on fish migration needs:

[0065] A hydrodynamic model of the Xiangjiaba-Luzhou section was constructed, coupled with the biological behavior simulation (ABM) module, and Luzhou, the lower boundary, was used as the fish release point. The fish that migrated to Lizhuang and above the Yibin section were considered successful migratory fish. By analyzing the changes in the proportion of successfully migrating fish under different downstream discharges of the Xiangjiaba Hydropower Station, the recommended discharge plan for fish migration in the downstream section of the dam was determined. The Xiangjiaba downstream discharge scenario was set to 2000-4000m during the model simulation. 3 / s, flow gradient interval is 250m 3 / s, the downstream water level is set according to the flow-water level fitting curve, and the corresponding water level under different discharge flows of Xiangjiaba is set. The model parameters related to the model are set as follows:

[0066] ① Force setting: During model simulation, the main forces are flow velocity and flow direction, and the simulation results of the hydrodynamic module are used. ② Model fish release setting: In the ABM module, the number of released particles is directly related to the simulation calculation time. In order to control the simulation calculation time, the simulation adopts the method of releasing 100 particles (model fish) at a time. At the beginning of the simulation, the reservoir area sets the release positions according to the distribution of flow velocity channels with different flow rates greater than 0.3m / s. The lower section of the dam is released in the downstream Luzhou section, and all releases are made on the water surface. ③ Setting of fish migration discrimination conditions: When particles (model fish) move, only horizontal movement is considered. The direction in the horizontal movement state is judged according to the flow velocity in the calculation of the hydrodynamic simulation results. The corresponding statement is:

[0067] Direction: IF(HDspeed>=HDmin), THEN HDdir+180°, ELSE HDdir

[0068] Speed: IF(HDspeed>=HDmin), THEN 0.5, ELSE HDspeed

[0069] Where: Direction is the swimming direction of fish, Speed ​​is the swimming speed of fish, HDspeed is the water flow velocity, HDdir is the water flow direction, and HDmin is the minimum migration stimulation flow velocity.

[0070] With a flow rate of 0.6 m / s as the limiting condition, the fish migration route from Xiangjiaba Dam to Luzhou River was simulated. Figure 3 By counting the changes in the proportion of model fish that successfully migrated in the river section downstream of the dam, the appropriate downstream flow rate of Xiangjiaba Dam to ensure fish migration upstream was determined. The changes in the success rate of model fish upstream are shown in Figure 4 shown.

[0071] In general, as the discharge from Xiangjiaba increased, the proportion of model fish migrating to Lizhuang and Yibin sections gradually increased, and the success rate of upstream migration gradually increased, and the overall change trend showed a step-like growth.3 / s The success rate of upstream tracing increased the most in the downstream flow range, with an average increase of about 55% in the two sections. When the downstream flow was greater than 3000m 3 / s, the increase in the success rate of upstream migration slowed down. Taking into account the changes in the success rate of upstream migration and the natural water supply, in order to ensure that fish can migrate smoothly upstream to the spawning grounds at a lower water temperature, the recommended discharge flow rate for Xiangjiaba is 3000m 3 / s, at this time, the proportion of fish migrating to Yibin and Lizhuang sections is 60% and 69% respectively.

[0072] 3. Determine the rising flow and peak flow of the second stage based on the habitat simulation method:

[0073] The hydrodynamic simulation results of MIKE21 in the Xiangjiaba-Luzhou section were constructed, and the habitat simulation method was used to analyze the changes in the suitable habitat area for spawning of drifting-egg fish in the downstream section of the dam under different discharge flow scenarios. Taking 80% of the maximum suitable habitat area as the control target, the suitable discharge flow to stimulate the spawning of drifting-egg fish was determined. The changes in the weighted available area (WUA) of suitable habitat for spawning of drifting-egg fish under different discharge scenarios are shown in Figure 2. Figure 5 shown.

[0074] from Figure 5 It can be seen from the figure that the weighted available area (WUA) of fish suitable for spawning under different spawning water temperature preferences downstream of Xiangjiaba Dam has a similar trend with the increase of reservoir discharge, showing a trend of first increasing and then slowly decreasing. For fish that prefer to spawn under low temperatures, when the discharge of Xiangjiaba Dam is 1000m3 / s, the WUA downstream of the dam is the smallest, which is 7.57km 2 ; Then, as the discharge flow increases, it gradually increases. When the discharge flow increases to 4000m 3 / s, the corresponding WUA below the dam is the largest, which is 11.58 km 2 ; As the discharge further increases, the WUA below the dam shows a slow decreasing trend. When the discharge reaches 6000m3 / s, the WUA below the dam is 10.23km 2 For fish that prefer high temperatures to spawn, when the discharge from Xiangjiaba is 1000m3 / s, the WUA downstream of the dam is the smallest, at 3.05km. 2 ; Then, as the discharge flow increases, it gradually increases. When the discharge flow increases to 4600m 3 / s, the corresponding WUA below the dam is the largest, which is 12.05km 2 As the discharge further increases, the WUA below the dam shows a slow decreasing trend. When the discharge reaches 6000m3 / s, the WUA below the dam is 11.79km 2 .

[0075] The flow corresponding to the maximum WUA is taken as the most suitable discharge flow, and the flow corresponding to 80% of the maximum WUA is taken as the appropriate discharge flow range, and then the starting flow is determined according to the lower boundary of the appropriate flow range. The appropriate discharge flow for spawning drifting eggs under Xiangjiaba at different dispatching times is shown in Table 2.

[0076] Table 2 Suitable discharge flow of Xiangjiaba Hydropower Station to stimulate spawning of drifting egg-laying fish

[0077]

[0078] 4. Analysis of natural flooding process:

[0079] The flood indexes were analyzed based on the natural hydrological process during the spawning period (April-July), including the duration of flood, daily increase in water level, and daily increase in flow. First, combined with the fish egg monitoring data of the Yibin and Jiangjin sections of the Yangtze River mainstream in 2022-2023 and the daily flow and water level data of the same period, the effective flood process standards for stimulating the spawning of drifting egg-laying fish were defined as constraints for subsequent statistical flood indexes. The results are as follows Figure 6 shown.

[0080] According to the 75% guarantee rate standard, the minimum requirements for each parameter of the effective water rise process are determined. The effective water rise process should last no less than 3 days, which is consistent with the result that the spawning scale is greatly affected by the flow increase in the 2 days before spawning. The total water level increase in April and May should be no less than 1m, and the total water level increase in June and July should be no less than 2.5m. The average daily flow increase in April and May should be no less than 213m. 3 / s, the total water level increase from June to July should not be less than 653m 3 / s. The water level rise process standards for effectively stimulating the spawning of drifting egg-laying fishes during different spawning periods are shown in Table 3.

[0081] Table 3 Standards for effective water rise process to stimulate fish spawning

[0082] Spawning time Duration of flood Total water level rise Average daily traffic growth April-May No less than 3 days Not less than 1m <![CDATA[Not less than 213m 3 / s]]> June-July No less than 3 days Not less than 2.5m <![CDATA[Not less than 653m 3 / s]]>

[0083] Based on the above-mentioned flooding process standards, and according to the measured daily flow and water level data from Huadan Station and Pingshan Station in the lower reaches of the Jinsha River from April to July 1956 to 1998, the natural flooding process that effectively stimulates fish spawning is analyzed, and the relevant parameters of the flooding process that stimulates the spawning of fish that lay drifting eggs are determined, namely, the proportion of the average daily flow increase to the multi-year average flow and the duration of the flooding. Figure 7 and Figure 8 shown.

[0084] According to the statistical results, from April to May, under natural conditions, the duration of water rise at Huadan Station was concentrated in 6-8 days, and the average daily flow rate increased by 7%-12% of the multi-year average flow rate; the duration of water rise at Pingshan Station was concentrated in 5-6 days, and the average daily flow rate increased by 5%-9% of the multi-year average flow rate; from June to July, under natural conditions, the duration of water rise at Huadan Station was concentrated in 5-8 days, and the average daily flow rate increased by 20%-27% of the multi-year average flow rate; the duration of water rise at Pingshan Station was concentrated in 4-7 days, and the average daily flow rate increased by 18%-24% of the multi-year average flow rate.

[0085] Based on the analysis results of the natural flood process indicators of Huadan Station and Pingshan Station, the flood process requirements of Xiangjiaba Dam were set according to the 75% guarantee rate standard. In order to meet the spawning requirements of drifting egg-laying fish in April and May, the flooding duration is at least 6 days, and the daily flow increase is not less than 7% of the multi-year average flow, that is, 325m 3 / s; In order to meet the spawning requirements of drifting egg-laying fish in June and July, the water level rises for about 5 days, and the daily flow rate increase is not less than 20% of the multi-year average flow rate, that is, 926m 3 / s, the results are shown in Table 4.

[0086] Table 4 Requirements for the flooding process below Wudongde Dam and Xiangjia Dam

[0087]

[0088] 5. Analysis of natural water withdrawal process

[0089] After the flooding process is met, the reduction of daily flow and the time of water withdrawal need to be constrained. The water level fluctuation within 7 days under natural conditions is used as the indicator of water withdrawal process. According to the measured water level data of Huadan Station and Pingshan Station from April to July 1956 to 2000, the fluctuation of natural water level within 7 days is analyzed. The results are as follows: Fig. 9 shown.

[0090] Under natural conditions, the median water level fluctuation within 7 days at Huadan Station is about 0.75m, and that at Pingshan Station is about 1.31m. Therefore, when ecological regulation is in the process of water withdrawal, the daily water level drop below Wudongde Dam should be less than 0.75m, and the corresponding flow fluctuation should be less than 560m. 3 / s; the daily water level drop below Xiangjiaba should be less than 1.31m, and the corresponding flow amplitude should be less than 1200m 3 Considering that there are few natural river channels below Wudongde Dam, it is difficult to meet the hydrodynamic conditions required for fish eggs to drift when the water is withdrawn according to the indicators under the natural state. Combined with the above research, the absolute flow rate must always be greater than 5000m in the first three days of the withdrawal period below Wudongde Dam. 3 / s. The requirements for the water withdrawal process below the dam are as shown in Table 5:

[0091] Table 5 Requirements for water withdrawal process below Wudongde Dam and Xiangjia Dam

[0092]

[0093] 6. “Artificial flood peak” scheme for spawning needs of fish with drifting eggs:

[0094] According to the above research, based on the appropriate discharge flow index for spawning of fish that lay drifting eggs and the requirements of the relevant water rise and fall process, an "artificial flood peak" ecological dispatching scheme for the spawning needs of fish that lay drifting eggs below Wudongde Dam and Xiangjiaba Dam is proposed. When the water temperature below Xiangjiaba Dam reaches 16-18℃, the "artificial flood peak" ecological dispatching for the spawning of fish that prefer to lay eggs under low temperatures will be started. Combined with the relevant research results above, the outflow flow in the first stage of the water rise process is set according to the needs of fish migration stimulation, which is 3000m 3 / s, the total duration of the flood is no less than 4 days, and the daily increase in flow is 500m 3 / s, peak flow rate is greater than 5000m 3 / s; the duration of the water withdrawal process should be no less than 3 days, and the daily flow rate drop should not exceed 1200m 3 / s. When the water temperature downstream of Xiangjia Dam reaches 21-22℃, the "artificial flood peak" ecological dispatch for spawning fish that prefer high temperature to spawn is started. Combined with the above research results, the outflow flow in the first stage of the flooding process is 3000m 3 / s, the total duration of the flood is no less than 4 days, and the daily increase in flow is 950m 3 / s, peak flow rate is 6800m 3 / s; the duration of the water withdrawal process should be no less than 3 days, and the daily flow rate drop should not exceed 1200m 3 / s. The specific process of water rise and fall is shown in Table 6.

[0095] Table 6 The process of “artificial flood peak” under Xiangjiaba Dam

[0096]

[0097]

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for regulating the rising and falling water process of fish that lay drifting eggs during the breeding period, characterized in that: The following steps are involved: S1. Divide different ecological scheduling processes and indicate water temperature according to the spawning amount and water temperature monitoring data; S2. When the water temperature in the spawning ground reaches the indicated water temperature, the discharge of the upstream reservoir is increased to start the first stage of water rise. This stage is mainly to stimulate fish migration. The reservoir discharge is the minimum flow rate Q during the migration period. 洄 , duration d 洄 ; Minimum flow rate Q during migration period 洄 The specific methods for determining include: The hydrodynamic model was constructed using MIKE 21, and the roughness coefficient and viscosity coefficient were verified. The fish migration trajectory discrimination formula was coupled into the hydrodynamic model through the biological behavior simulation module. The discrimination statement is as follows: Speed: IF(HDspeed>=HDmin), THEN 0.5, ELSEHDspeed Direction: IF(HDspeed>=HDmin), THENHDdir+180°, ELSE HDdir Where: Direction is the swimming direction of the fish, Speed ​​is the swimming speed of the fish, HDspeed is the water flow velocity, HDdir is the water flow direction, and HDmin is the minimum migration stimulation flow velocity; Simulate the distribution of potential channels for fish migration under different flow rates; According to the relationship between the distance of potential migration channel and flow rate, the minimum flow rate Q that can effectively stimulate fish reproductive migration is determined. 洄 ; Determine the duration d of the migration process based on the simulation results 洄 ; S3. After the migratory stimulation is completed, the second stage of water rise begins. This stage is mainly to stimulate fish spawning. The reservoir discharge gradually increases, increasing by ΔQ every day. 涨 , duration d 涨 , Q 峰 As peak flow; Daily water rise ΔQ 涨 and duration of flooding d 涨 The specific determination methods include: analyzing the spawning data and the measured flow data of the same period to determine the minimum standard of the flood process that can stimulate fish spawning, including the total water level increase standard and the daily flow increase standard; analyzing the natural flow and water level process to clarify the natural change state and threshold of the flow, water level and flood duration during each flood process under natural conditions; Peak flow Q 峰 According to the evaluation of fish spawning habitat suitability, the flow corresponding to 80% of the maximum suitable habitat area is used as the flood range, that is, Q 初 ~Q 峰 , where Q 初 As the initial flow rate of flooding, Q 峰 As peak flow; S4. After the flooding process is over, a high flow rate Q is required to keep the fish eggs drifting safely. 漂 , duration d 漂 ; Flow rate Q to maintain safe drift of fish eggs 漂 The specific method for determining the flow rate Q includes: simulating the drifting trajectory of fish eggs under different flow rates based on the hydrodynamic model and the fish egg drifting model, and determining the appropriate flow rate Q that can maintain the drifting of fish eggs, taking the duration d drift of more than 50% of the fish eggs as the standard. 漂 ; Drifting duration of fish eggs 漂 The specific method for determining the duration of the drifting and hatching of fish eggs includes: collecting the drifting and hatching time of key protected fish species in each period; analyzing the correlation between the drifting and hatching time of fish eggs and water temperature, and determining the duration of the drifting and hatching of fish eggs based on the confidence interval. 漂 ; S5. During the water withdrawal process, according to the analysis of natural hydrological processes, set the daily water withdrawal amplitude ΔQ 退 , duration d 退 ; Daily water withdrawal amplitude ΔQ 退 and duration d 退 The specific method for determining ΔQ includes: analyzing the water level fluctuation within 7 days under natural conditions as the standard of daily water level fluctuation; setting the daily water withdrawal amplitude ΔQ according to the water level-discharge relationship curve. 退 ; Determine the duration of water withdrawal d based on the daily flow drop and the flow before water rise 退 ; S6. Form a refined control plan for the flooding and receding process in different time periods and processes, including the reservoir discharge flow and duration at each stage; the process refers to the flooding process being divided into two stages and the receding process being divided into two stages. The first stage of the flooding process is mainly to stimulate fish migration, and the reservoir discharge flow is not less than Q 洄 , duration d 洄 The second stage of the flooding process is mainly to stimulate fish spawning, and the reservoir discharge gradually increases to Q 峰 , the daily increase in traffic is no less than ΔQ 涨 , the duration is not less than d 涨 ; In the first stage of the water withdrawal process, the reservoir discharge flow is not less than Q 漂 , the number of days to be maintained is not less than d 漂 In the second stage of the water withdrawal process, the reservoir discharge gradually changes from Q 漂 Reduce to the flow rate before flooding, and the daily flow rate decrease shall not be less than d 退 .

2. The method for controlling the water rise and fall process during the breeding period of fishes that lay drifting eggs according to claim 1, characterized in that: The method for determining the ecological scheduling process and the indicated water temperature in S1 specifically includes: collecting daily spawning volume and water temperature monitoring data of drifting eggs; using multiple regression analysis to clarify the impact mode and threshold of water temperature on spawning scale; determining different ecological scheduling opportunities based on the water temperature threshold, and clarifying the key fish to be protected in each scheduling process.

3. The method for controlling the water rise and fall process during the breeding period of fishes laying drifting eggs according to claim 1, characterized in that: The fish spawning habitat suitability evaluation specifically includes: analyzing fish habitat preferences at different spawning periods, constructing habitat suitability curves for water depth and flow velocity; using a hydrodynamic model to analyze the effective habitat area under different flow rates; establishing a fitting curve of the relationship between the effective habitat area and flow rate, and determining the suitable ecological flow range.

4. The method for controlling the water rise and fall process during the breeding period of fishes laying drifting eggs according to claim 1, characterized in that: In the detailed control scheme of the water rise and fall process in S6, the time periods refer to different ecological scheduling periods determined according to the spawning water temperature, and each scheduling period corresponds to different fish needs.

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