A method for determining the necessity of stratified water intake at water intakes of water diversion and regulation projects

Abstract

The present invention discloses a method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project. The method comprises the following steps: step 1: collecting data on the parameters of the water diversion and regulation project and the environmental status of the water source area, the water diversion line area and the water receiving area; step 2: predicting the water temperature along the water diversion channel; step 3: predicting the water temperature of rivers and lakes in the water receiving area; and step 4: determining the acceptable degree of water temperature changes of ecologically sensitive targets of rivers and lakes in the water receiving area. The present invention has the advantage of being able to quickly identify the necessity of water temperature stratification.

Description

Technical Field

[0001] The invention relates to the field of environmental protection, and more specifically to a method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project. Background Art

[0002] Water diversion and regulation projects are generally composed of water source projects, water transmission projects, control and cross-buildings, regulating reservoirs, and terminal supporting projects. They are generally divided into water source areas and water source downstream areas, water transmission line areas, and water receiving areas in space. The replenishment rivers, lakes, and reservoirs are important components of the water receiving area. They are located at the end of the water transmission lines (main and branch lines) of the water diversion and regulation projects. They generally play the role of water supply sources for different industries (living, industry, or agriculture) in the water receiving area. The water diversion and regulation projects realize direct or indirect water replenishment for different industries by replenishing water to the replenishment rivers, lakes, and reservoirs. However, large-scale water diversion and regulation projects generally span two or more river basins or water resource zones, and have the characteristics of wide coverage and diverse environmental impacts. Affected by the climatic conditions of different river basins (regions), the types of water source projects, or the differences in water intake depths in the water source area, there may be differences in water temperature between the water source area and the replenishment river, lake, and reservoir basins. The implementation of water diversion and regulation projects may change the temporal and spatial distribution characteristics of the water temperature of the replenishment rivers, lakes, and reservoirs. Therefore, the construction and operation of water diversion projects may affect the water temperature of rivers, lakes and reservoirs while improving the water shortage situation in the receiving areas;

[0003] After a long period of adaptation, aquatic plants and animals complete regular reproduction and growth activities under periodically changing temperature conditions to maintain the stability of the water ecosystem. However, after the operation of the water diversion and regulation project, when the water temperature of the replenishment river, lake (reservoir) during the sensitive period is lower than the temperature required for the normal reproduction and growth of aquatic plants and animals, the key life history processes and biomass of aquatic plants and animals will be adversely affected by hysteresis and reduction, and affect the stability of the ecosystem. Therefore, the prediction of the water temperature of the replenishment river, lake (reservoir) in the water receiving area should be an important part of the ecological and environmental impact demonstration of the water diversion and regulation project. When the water flow at the water intake of the water source area water intake building at a depth or elevation is transmitted through the water transfer building (channel) and has an adverse effect on the water temperature of the replenishment river, lake (reservoir), the optimization suggestions for the water intake temperature of the water diversion and regulation project should be put forward. For water source areas with obvious water temperature stratification, stratified water intake is the main direction of water intake temperature optimization. However, the stratified water extraction scheme is mainly used for the downstream scheme of hydropower projects. Due to the complexity of water temperature influencing factors (water transmission channel length, air pressure, geothermal resources, etc.) in different water transmission channels (water transmission tunnels, water transmission channels and water transmission rivers and lakes, etc.) and the diversity of water transmission channel combinations, the current ecological and environmental impact assessment of water diversion and regulation projects mainly focuses on the hydrological situation and water quality changes of replenishment rivers and lakes (reservoirs). Even when conducting water temperature change analysis of replenishment rivers and lakes, the water temperature of the water source area is directly used as the input condition, ignoring the cooling or rewarming effect during the water transmission process. It is impossible to accurately judge the impact of water from the water source area of ​​the water diversion and regulation project on the water temperature of the replenishment rivers and lakes and whether stratified water extraction assessment is needed. For example, even though the water temperature at the water intake of the water source area's water intake building is lower than the water temperature at the replenishment point of the replenishment river or lake, after being transferred through the water transfer channel, the water temperature of the water transfer water in the water source area rises to close to the water temperature at the replenishment point of the replenishment river or lake, there is no need to further predict the change in the water temperature of the replenishment river or lake, and at the same time, it can be concluded that there is no need to conduct a stratified water intake demonstration in the water source area, which simplifies the demonstration of the impact of water temperature on the water diversion project; on the contrary, when the water temperature of the water transfer water in the water source area is significantly lower than or higher than the water temperature at the replenishment point of the replenishment river or lake after being transferred through the water transfer channel, it is necessary to further carry out water temperature prediction of the replenishment river and lake and analyze the acceptability of its changes, so as to provide a data basis for identifying the necessity of stratified water intake in the water source area. However, in the water ecological environment demonstration of water diversion and regulation projects, there is no systematic technical system for identifying the water temperature changes along the water diversion and regulation projects, the water temperature changes in the replenishment rivers and lakes, and their acceptability, which cannot provide technical support for the necessity of water temperature optimization at the water intake, resulting in a lot of time and money being wasted on unnecessary stratified water intake design work;

[0004] Therefore, there is an urgent need to develop a method for determining the necessity of stratified water intake at water intakes of water diversion and regulation projects that can quickly identify the necessity of water temperature stratification. Summary of the invention

[0005] The purpose of the present invention is to provide a method for judging the necessity of stratified water intake at the water intake of a water diversion and regulation project, taking into account the influence of the warming or cooling effect of different water transfer channels of a long-distance water diversion and regulation project on the water temperature of replenished rivers and lakes and ecologically sensitive targets, a method for judging the water temperature changes at the water intake-water transfer channel-replenishment rivers and lakes of a water diversion and regulation project driven by the inflow and water temperature of the water source area, the geothermal resources along the water transfer channel, and the meteorological and hydrological conditions of the replenished rivers and lakes in the receiving area, as well as the degree of acceptance of water temperature changes by ecologically sensitive targets in the replenishment rivers and lakes is proposed, which can quickly identify the necessity of water temperature stratification and avoid wasting a lot of time and money on unnecessary stratified water intake design work.

[0006] In order to achieve the above object, the technical solution of the present invention is: a method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project, characterized in that it comprises the following steps:

[0007] (1) Collection of data on water diversion project parameters and the environmental status of water source areas, water diversion areas and water receiving areas;

[0008] (2) Water temperature prediction along the water transfer channel;

[0009] The water transfer channels of water diversion and regulation projects mainly include water transfer tunnels, water transfer open channels and water transfer rivers and lakes, among which water transfer tunnels can be divided into pressurized water transfer tunnels and non-pressurized water transfer tunnels. Based on the water diversion flow and water temperature of the water source area and the heat source and sink (geothermal) data along the water transfer line in a certain period of time (day, ten days or month), according to the water temperature calculation models along different water transfer channels and the combination schemes between different water transfer channels (such as the water transfer tunnel-water transfer river and lake-water transfer open channel combination scheme or the water transfer open channel-water transfer river and lake-water transfer tunnel combination scheme), the water temperature along the water transfer channel of the water diversion and regulation project and the water temperature at the outlet are calculated;

[0010] (3) Water temperature forecast of rivers and lakes in the receiving area;

[0011] Based on the principle of simple application and short calculation time, the water temperature along the rivers and lakes in the receiving area is calculated based on the simplified water temperature prediction method of rivers and lakes after water replenishment, taking into account the change of hydraulic retention time of lakes and reservoirs after water replenishment.

[0012] (4) Determine the acceptable degree of water temperature change of ecologically sensitive targets of rivers and lakes in the water receiving area;

[0013] Based on the calculation results of water temperature of replenished rivers and lakes, by calculating the statistical values ​​of water temperature changes and the acceptability of water temperature changes for the ecological protection objects of replenished rivers and lakes, and according to the judgment standards for the acceptability of water temperature changes for the ecological protection objects of replenished rivers and lakes, it is judged whether it is necessary to carry out stratified water intake demonstration and design work for the water diversion project water intake.

[0014] In the above technical solution, in step (1), the water diversion project parameters and the environmental status data of the water source area, the water diversion area and the water receiving area mainly include:

[0015] The water replenishment flow of the project in different typical years (flood, normal, dry and extremely dry years) and different periods (day, ten days, month); the parameters of the project water intake, mainly including the shape, size and bottom plate elevation of the water intake; the type of water transmission channel, mainly including the length, cross-sectional size and bottom plate elevation of tunnels, open channels and rivers and lakes;

[0016] Water temperature data at different water levels and depths at the project water intake (water source area) in different periods (daily, ten-day, monthly, covering the flood, normal and dry seasons) in the past three years;

[0017] The types of geothermal resources distributed along the water transfer channel, the temperature at the center of the geothermal resource, the vertical distance from the center of the geothermal resource to the water transfer channel, and the equivalent thermal conductivity and heat flux density of the geothermal resources;

[0018] The upstream inflow flow of the replenishment point of the replenishment river and lake, and the water temperature data (vertical mixed water sample measurement data) along the replenishment river and lake (including the upstream inflow of the replenishment point) in different periods (daily, ten days, monthly, covering the wet, normal and dry seasons) in the past three years;

[0019] Meteorological data such as air pressure and temperature at major meteorological stations in water source areas, water delivery channels, and water replenishment rivers and lakes in different periods (daily, ten-day, monthly, covering wet, normal, and dry seasons) over the past three years;

[0020] Replenish water to ecologically sensitive targets of rivers and lakes (aquatic germplasm resources protection areas, fish “three fields and one channel”) and the water temperature requirements for reproduction and growth.

[0021] In the above technical solution, in step (2), the water temperature prediction method along different water conveyance channels such as water conveyance rivers, lakes, and water conveyance tunnels is as follows:

[0022] The calculation method of water temperature along the water supply river and lake is as follows:

[0023] Considering the flow characteristics of water-carrying rivers and lakes, assuming that the water-carrying rivers and lakes are evenly mixed along the cross section, the water-carrying rivers and lakes are divided into River and lake section Water temperature at outlet time t The calculation is as follows:

[0024] (1)

[0025] In the formula, Segmentation of water channels Inlet water temperature, °C; Segmentation of water channels Length, m; Segmentation of water channels Average flow velocity, m / s; , and Divide rivers and lakes into sections for water delivery Calculation coefficient of ; is numbered;

[0026] (2)

[0027] (3)

[0028] (4)

[0029] (5)

[0030] In the formula, is the density of water, kg / m 3 ; is the specific heat of water, J / (kg·℃); Segmentation of water channels Lateral inflow per unit river length, m 2 / s; Segmentation of water channels Water temperature of the side inflow, ℃; Divide rivers and lakes into sections for water delivery Section width, m; Segmentation of water channels Local atmospheric pressure, hPa; Segmentation of water channels Atmospheric temperature, °C; Segmentation of water channels Air-water convection heat exchange coefficient, W / (m 2 ℃); Segmentation of water channels The speed of the atmosphere relative to the water flow, m / s; , , Divide rivers and lakes into sections for water delivery Calculation parameters of , , Segmentation of water channels Calculated variables of

[0031] The starting point of the water supply river-lake section ( The water temperature at time t is closely related to the flow rate and temperature of the water from the upstream of the water supply river and lake section and the water source area. This is equivalent to the boundary conditions of formulas (1)-(5); It can be expressed as:

[0032] (6)

[0033] In the formula, , They are the water from the upstream of the water-transfer river and lake section and the water from the water source area (after being transferred through the water transfer channel), m 3 / s; , are the water temperatures of the upstream water from the water supply river and lake section and the water source area, ℃; , They are , Density of water at temperature, kg / m 3 ; , They are , Constant pressure hot melt at temperature, kJ / (kg℃);

[0034] Water transfer tunnels are divided into two types: pressure tunnels and non-pressure tunnels. The water temperature along the tunnel is calculated as follows:

[0035] Pressure tunnel: Considering the temperature transfer between water flow and rock medium in the water conveyance tunnel, the tunnel is divided into Section, hole section Water temperature at outlet time t The calculation is as follows:

[0036] (7)

[0037] In the formula, Segmentation of water channels Flow rate, m 3 / s; Segmentation of water channels Length, m; and Segmentation of pressurized tunnels The calculation parameters are expressed as , ,in, For the tunnel The inner diameter of the tunnel, m; For the tunnel The water temperature of the isothermal layer, ℃; For the tunnel Heat exchange coefficient between water and tunnel, W / (m 2 ℃); other symbols have the same meanings as above;

[0038] (8)

[0039] (9)

[0040] In the formula, For the tunnel The outer diameter of the tunnel lining, m; For the tunnel The outer diameter of the temperature-changing layer is 2~3 times of, m; and The tunnel sections Thermal conductivity of lining and thermal conductivity of surrounding rock temperature-varying layer, W / (m·℃); For the tunnel Height of ground point above sea level, m; For the tunnel Temperature at the center of geothermal resources, °C; For the tunnel Distance from geothermal center to water delivery channel, m; For the tunnel Equivalent thermal conductivity of geothermal resources, W / (m·℃); For the tunnel Geothermal resource heat flux, W / m 2 ; The meanings of other symbols are the same as before;

[0041] Pressureless tunnel: Pressureless tunnel is connected to the atmosphere. The change of water temperature along the pressureless tunnel is related to the temperature transfer process between rock medium and atmosphere. Water temperature at outlet time t The calculation is as follows:

[0042] (10)

[0043] (11)

[0044] (12)

[0045] (13)

[0046] in, For the tunnel Tunnel bottom width, m; Segmentation of water channels Water flow area, m 2 ; Segmentation of unpressured tunnels Heat exchange coefficient between water and tunnel, W / (m 2 ℃); For the tunnel Thickness of lining vertical wall or base plate, m; For the tunnel The thickness of the surrounding rock temperature change layer is the diameter of the hole. 1~2 times of, m; For the tunnel Wet perimeter, m; , and Segmentation of unpressured tunnels Calculation coefficient of ; , , Segmentation of unpressured tunnels Calculation parameters of; other symbols have the same meanings as before;

[0047] The water temperature along the open channel is calculated as follows:

[0048] The water temperature of the open channel is related to the air temperature, the structure and length of the open channel. When the temperature When the temperature is less than -10℃, the channel section Water temperature at outlet time t It is expressed as:

[0049] (14)

[0050] (15)

[0051] (16)

[0052] (17)

[0053] (18)

[0054] (19)

[0055] In the formula, For channel section Water surface width, m; Divide the open channel into sections Heat exchange coefficient, W / (m 2 ℃); Divide the open channel into sections Equivalent heat exchange coefficient between water body and channel bed, W / (m 2 ℃); Divide the open channel into sections Equivalent ground temperature of the channel bed, ℃; Divide the open channel into sections Average ground temperature of the subgrade under the channel floor, °C; Divide the open channel into sections Average ground temperature of the slope substratum, °C; Divide the open channel into sections The heat exchange coefficient between the water body and the channel is used to calculate the heat exchange coefficient between the water body and the slope , heat exchange coefficient between water and bottom plate ,W / (m2 ℃); Divide the open channel into sections The wet week, The bottom of the canal is wet. is the wetted perimeter of the channel slope, , m; Divide the open channel into sections The number of layers of the slope or channel bottom cross-section structure; Indicates the water channel segmentation Middle slope or channel bottom Thickness of the layer, m; Indicates the water channel segmentation Middle slope or channel bottom Thermal conductivity of the layer, W / (m 2 ℃); , For temperature Open channel segmentation for water supply when <-10℃ Calculation parameters of; other symbols have the same meanings as before;

[0056] When the temperature ≥-10℃, channel section Water temperature at outlet time t It is expressed as:

[0057] (20)

[0058] (twenty one)

[0059] (twenty two)

[0060] In the formula, , and Divide the open channel into sections Calculation coefficient of ; , , For temperature ≥-10℃ water delivery open channel segmentation Calculation parameters of =0.158×10 -3 p a ; The meanings of other symbols are the same as before.

[0061] In the above technical solution, in step (3), the water replenishment rivers and lakes in the water receiving area include water replenishment rivers and water replenishment lakes and reservoirs. The water temperature calculation method of the water replenishment rivers and water replenishment lakes and reservoirs in the water receiving area is as follows:

[0062] The water temperature forecast range of the replenishment rivers in the water receiving area includes the river section below the replenishment point to the estuary, and the replenishment rivers are divided into Section, water supply river section of the receiving area Water temperature at the end time t The calculation is as follows:

[0063] (twenty three)

[0064] In the formula, Divide the river into sections for water replenishment Water temperature at the starting end, °C; Divide the river into sections for water replenishment Length, m; Divide the river into sections for water replenishment Average flow velocity, m / s; , and Divide the river into sections for water replenishment Calculation coefficient of ; is numbered;

[0065] (twenty four)

[0066] (25)

[0067] (26)

[0068] (27)

[0069] In the formula, is the density of water, kg / m 3 ; is the specific heat of water, J / (kg·℃); Divide the river into sections for water replenishment Lateral inflow per unit river length, m 2 / s; Divide the river into sections for water replenishment Water temperature of the side inflow, ℃; Divide the river into sections for water replenishment Average section width, m; Divide the river into sections for water replenishment Local atmospheric pressure, hPa; Divide the river into sections for water replenishment Atmospheric temperature, °C; Divide the river into sections for water replenishment Air-water convection heat exchange coefficient, W / (m 2 ℃); Divide the river into sections for water replenishment The speed of the atmosphere relative to the water flow, m / s; , , Divide the river into sections for water replenishment Calculation parameters of

[0070] is the water temperature at the starting end of the replenishment river at time t, which is closely related to the flow rate and temperature of the upstream water of the replenishment river and the replenishment point at the end of the water transfer channel, and is expressed as:

[0071] (28)

[0072] In the formula, , The water from the upstream of the replenishment point of the replenishment river and the replenishment point at the end of the water transfer channel are respectively, m 3 / s; , are the water temperatures of the upstream water from the water supply river and lake section and the replenishment point at the end of the water supply channel, ℃; , They are , Density of water at temperature, kg / m 3 ; , They are , Constant pressure hot melt at temperature, kJ / (kg℃); according to different water delivery channel combination schemes, is the water temperature at the outlet of the last type of water delivery channel at time t, i.e., the water delivery river, lake, tunnel or open channel segment in step (2). The calculated value at time t;

[0073] After the implementation of the water diversion project, the water temperature of the water supply lakes and reservoirs in the receiving area is affected by the inflow and water temperature conditions of the basin, the water supply volume and water temperature conditions:

[0074] When the hydraulic retention time of the water supply lakes and reservoirs in the receiving area is less than or equal to 14 days after the water diversion project is implemented, the prediction method of the water temperature impact of the water supply lakes and reservoirs in the receiving area is the same as the prediction method of the water temperature of the water supply river;

[0075] When the water diversion project is implemented, the hydraulic retention time of the water supply lake in the receiving area is greater than 14 days. tributaries into the lake, the water temperature at any point in the water area of ​​the lake is It is expressed as:

[0076] (29)

[0077] In the formula, , The water inflow within the reservoir catchment area and the water replenishment at the end of the water delivery channel are respectively, m 3 / s; , They are the water temperatures of the tributaries within the reservoir catchment area and the replenishment water temperature at the replenishment point at the end of the water transfer channel, ℃; , They are , Density of water at temperature, kg / m 3 ; , They are , Constant pressure hot melt at temperature, kJ / (kg℃); according to different water delivery channel combination schemes, is the water temperature at the outlet of the last type of water channel at time t, i.e., the water temperature of the water conveyance river, lake, tunnel or open channel segment in step (2). The calculated value at time t.

[0078] In the above technical solution, in step (4), the method for calculating the statistical value of water temperature change of the ecological protection object of the water supply river and lake in the water receiving area is as follows:

[0079] Divide the replenished rivers and lakes into Section, with water replenishment river and lake sections There are H water ecological protection objects distributed in the During the sensitive period , The suitable temperature upper and lower limits are and , Statistical value of water temperature change at time t It is expressed as:

[0080] (30)

[0081] (31)

[0082] In the formula, t is At the time of analysis, a full calendar year is sorted from 1 to 365 days, then 1≤ ≤365; for Water supply river and lake segment Temperature at the end at time t, ℃; Water ecological protection object Water temperature change statistics It is expressed as:

[0083] (32).

[0084] In the above technical solution, in step (4), the method for calculating the acceptable degree of water temperature change of the ecological protection object of the water supply river and lake in the water receiving area is as follows:

[0085] Statistics of water replenishment for rivers and lakes The total number of water ecological protection objects in river sections is , the acceptable degree of water temperature change of water ecological protection objects in replenished rivers and lakes The degree of change in water temperature of water ecological protection objects of replenished rivers and lakes 2. Importance of water ecological protection objects Related, expressed as:

[0086] (33)

[0087] Degree of change in water temperature of water ecological protection objects It indicates the ratio of the total number of analysis periods that meet the water temperature requirements during the sensitive period after the water temperature changes to the total length of the sensitive period, expressed as:

[0088] (34)

[0089] In the formula, when When the value is 1, it means that the water temperature change has an impact on the water ecological protection object. No effect; when When the value is 0.7, it means that the water temperature change has an impact on the water ecological protection object. Causes minor impact; when When the value is 0.4, it means that the water temperature change has a great impact on the water ecological protection object. Cause a greater impact; when When the value is 0.1, it means that the water temperature change has an impact on the water ecological protection object. Cause serious impact;

[0090] Importance of water ecological protection objects and protection levels of water ecological protection objects About, The importance of each water ecological protection object It is expressed as:

[0091] (35)

[0092] In the formula, when =1, the water ecological protection object is the endangered species or above listed in the Red List of Endangered Animals of China, the Red List of Biodiversity of China or the IUCN List; =2, the objects of water ecological protection are species listed in the national and local key protected wild animals and plants list; =3, the objects of water ecological protection are rare, unique or important aquatic germplasm resources; =4, the objects of water ecological protection are other species with important ecological, scientific and social values ​​and in need of protection.

[0093] In the above technical solution, in step (4), the criteria for judging the acceptability of water temperature changes of water ecological protection objects in the water-receiving area are as follows:

[0094] Acceptable degree of water temperature change of water ecological protection objects in water-replenishing rivers and lakes in the water receiving area It is the overall acceptability of water temperature changes for multiple water ecological protection objects, referring to the water temperature change degree of water ecological protection objects. Take value, when When it is less than or equal to 0.7, the water intake of the water diversion project needs to carry out in-depth demonstration and design work on stratified water intake; otherwise, there is no need to carry out demonstration and design work on stratified water intake.

[0095] Compared with the prior art, the present invention has the following advantages:

[0096] (1) The present invention considers the influence of geothermal, meteorological and hydrological conditions near water transfer channels such as tunnels, open channels, rivers and lakes on the temperature rise or fall of water transfer, and proposes a method for calculating the water temperature along different water transfer channels, providing a method for predicting the water temperature at the outlet of the water transfer channel of the water diversion project with different water transfer channel combinations such as tunnels, open channels and rivers and lakes (such as tunnel-river-lake-open channel or open channel-river-lake-tunnel, etc.), thereby improving the reliability of the water temperature prediction results of the replenishment rivers and lakes; and solves the problem that the traditional method system for the construction, calibration and verification of hydrodynamic water temperature models does not consider the influence of water transfer channels on the temperature rise or fall of water, and directly uses the water temperature of the water source area as the boundary condition for predicting the water temperature of the replenishment rivers and lakes in the water receiving area, resulting in water temperature calculation deviation, which makes the reliability of the water temperature prediction results of the replenishment rivers and lakes questionable;

[0097] (2) Considering the change of hydraulic retention time of the water-replenishing lakes and reservoirs in the receiving area after water replenishment, a simplified water temperature prediction method along the rivers and lakes is proposed, which saves about 92% of the working time compared with the traditional method system of hydrodynamic water temperature model construction, calibration and verification. It also solves the shortcomings of the traditional method system, such as the key processes of hydrodynamic water temperature model construction, calibration and verification require a lot of time and financial costs;

[0098] (3) Taking into account the differences in the sensitive periods and suitable water temperature ranges of different water ecological protection objects, a method for calculating the statistical value of water temperature changes of a single water ecological protection object was proposed; considering the importance of different water ecological protection objects, from the perspective of coordinated protection of multiple water ecological protection objects, a calculation method and judgment standard for the acceptability of water temperature changes of water ecological protection objects in the water-receiving area were proposed, creatively realizing the rapid judgment of the acceptability of water temperature changes for the coordinated protection of multiple water ecological protection objects, filling the current technical gap in the judgment of the acceptability of water temperature changes for the coordinated protection of multiple water ecological protection objects;

[0099] (4) The present invention comprehensively considers the water temperature prediction of the water transfer channel, the water temperature prediction of the replenishment river and lake, and the analysis of the acceptability of the water temperature change of the replenishment river and lake, and proposes a method for judging the necessity of stratified water intake at the water intake of the water diversion project, which creates conditions for quickly identifying the necessity of stratified water intake and can quickly identify the necessity of water temperature stratification, thus avoiding wasting a lot of time and money on unnecessary stratified water intake design work. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 It is a flow chart of the present invention;

[0101] Figure 2 The water replenishment process of a water diversion project in different typical years in the embodiment of the present invention;

[0102] Figure 3 The upstream water inflow process in different typical years after the implementation of a water diversion project in the embodiment of the present invention;

[0103] Figure 4 The water temperature characteristics of the water area near the water replenishment point of a water diversion project in the embodiment of the present invention;

[0104] Figure 5 The difference in water temperature along the replenishment river after the implementation of the test example and the embodiment of the present invention (in a normal water year);

[0105] Figure 6 The water temperature difference along the replenishment river after the implementation of the test example and the embodiment of the present invention (dry year);

[0106] Figure 7 It is the water temperature difference along the replenishment river after the implementation of the test example and the embodiment project in the present invention (in an extremely dry year). DETAILED DESCRIPTION

[0107] The following is a detailed description of the implementation of the present invention in conjunction with the accompanying drawings, but they do not constitute a limitation of the present invention and are only given as examples. At the same time, the advantages of the present invention are made clearer and easier to understand through the description.

[0108] At present, stratified water intake at water intakes is mainly used in the downstream discharge scheme of hydropower projects, which can effectively prevent the discharge of low-temperature water from causing adverse effects on the reproduction or normal growth of downstream water ecological protection objects (such as delayed reproduction period, slow growth, etc.). Similar to hydropower projects, affected by meteorological conditions or geothermal resources, long-distance water transportation of water diversion and regulation projects may cause the water temperature to drop or rise, further causing adverse effects on water ecological protection objects in replenished rivers and lakes (such as increased water temperature may shorten the reproduction period). In order to avoid the above-mentioned adverse effects, the present invention proposes a technical system for determining the necessity of stratified water intake at water diversion and regulation project intakes, filling the gap in the research on the necessity of determining stratified water intake at water diversion and regulation project intakes;

[0109] The present invention firstly collects the parameters of the water diversion and regulation project to grasp the elevation of the water intake of the project and its water intake process at different periods of the year, the combination form of water transmission channels and its spatial distribution; collects the environmental status data of the water source area, the water transmission line area and the receiving area of ​​the water diversion and regulation project to grasp the water level (water depth) process and vertical water temperature distribution characteristics of the water source area at different periods of the year, the spatiotemporal distribution characteristics of meteorological parameters such as air temperature and air pressure in the water transmission line area, the topographic and geomorphic characteristics, the spatial distribution of geothermal resources and their heat transfer parameters, the spatiotemporal distribution characteristics of meteorological parameters such as air temperature and air pressure in the receiving area, and the annual runoff process and water temperature data of the main control sections of the replenishment rivers and lakes in different typical years.

[0110] Furthermore, based on the elevation of the water intake and the vertical water temperature distribution characteristics of the water source area, the water flow rate and water temperature of the water intake under the condition of non-stratified water intake are determined, and the meteorological and heat source sink (geothermal) data along the water transmission line are considered. According to the water temperature calculation method along different water transmission channels and the combination schemes between different water transmission channels (such as the combination scheme of water transmission tunnel-water transmission river and lake-water transmission open channel or the combination scheme of water transmission open channel-water transmission river and lake-water transmission tunnel), the water temperature at the outlet of the water transmission channel of the water diversion project is calculated.

[0111] Furthermore, taking into account the differences in flow regimes of rivers and lakes and using hydraulic retention time as a parameter, the transformation of flow regimes from lakes to rivers after the implementation of the water diversion project is focused on. Based on a simplified method for predicting water temperature along rivers and lakes, the water temperature along the rivers and lakes in the receiving areas after the implementation of the water diversion project is calculated.

[0112] Furthermore, based on the calculation results of water temperature along the replenished rivers and lakes, combined with the types of water ecological protection objects distributed along the replenished rivers and lakes, sensitive periods (breeding periods) and the characteristics of suitable water temperature differences, by calculating the statistical values ​​of water temperature changes of water ecological protection objects and the acceptability of water temperature changes, and based on the criteria for judging the acceptability of water temperature changes of water ecological protection objects, suggestions are put forward on whether it is necessary to carry out stratified water intake demonstration and design work at the water intake of water diversion projects (such as Figure 1 As shown, Figure 1 The middle dotted lines indicate different combinations of water delivery channels).

[0113] In general, the various steps of the present invention are closely linked and easy to operate. They can quickly provide feedback on the changes in water temperature of rivers and lakes replenished after the implementation of the water diversion and regulation project and the degree of acceptance of water temperature changes by water ecological protection objects, thereby realizing rapid identification of the necessity of water temperature stratified water intake with high judgment accuracy, and providing a preliminary judgment basis for the demonstration and design of stratified water intake at the water diversion and regulation project water intake.

[0114] Embodiment: The present invention is now described in detail by taking the application of the present invention to a water diversion project to determine the necessity of stratified water intake, to verify the effectiveness of the present invention in rapidly identifying the necessity of stratified water intake by water temperature, with high judgment accuracy, and saving time and money. The present invention also has a guiding role in the application of the present invention to other long-distance water diversion projects.

[0115] In this embodiment, the water transfer channel of a water diversion project is a combination of tunnel-open channel-river, and there are many rare aquatic plants and animals in the water transfer channel;

[0116] In order to reduce the damage of the water diversion project to the rare aquatic plants and animals in the replenishment river, a water diversion project spent about 3 million yuan, used the traditional hydrodynamic water temperature model construction, calibration and verification methods, and spent one year to study the impact of the project implementation on the water temperature and ecosystem of the replenishment rivers and lakes in the water receiving area, carried out stratified water intake research and formulated a stratified water intake plan for the water intake. However, the verification conclusion showed that the implementation of the project would not affect the water ecosystem of the replenishment river and lake; the water diversion project spent a lot of time and money on unnecessary stratified water intake design work, and ignored the impact of the water transfer channel on the water temperature in the calculation, and directly used the water temperature in the water source area as the replenishment water temperature of the replenishment river replenishment point, which would affect the accuracy of the stratified water intake judgment (for example, when the water temperature at the starting end and the outlet end of the water transfer channel is different, the water temperature in the water source area is directly used as the replenishment water temperature of the replenishment river replenishment point. The source data error is large, which will lead to a large error in the result obtained by using the source data calculation, affecting the accuracy of the judgment).

[0117] The method of the present invention is now used to determine the necessity of stratified water intake at a water intake of a water diversion project in this embodiment, which mainly includes the following steps:

[0118] (1) Collect data on water diversion project parameters and the environmental status of water source areas, water diversion areas, and water receiving areas

[0119] 1) A water diversion project uses a tower-type water intake for water intake. The water intake tower is 26m long and 30m wide in the downstream direction, with a bottom plate top elevation of 127.0m and a tower top elevation of 175.3m. The project water supply main line consists of inlet buildings, water supply tunnels-open channels-rivers, outlet buildings, and maintenance traffic tunnels, with a total length of about 194.8km, of which the water inlet is 26.0m long, the water supply tunnel is about 128.2km long, the water supply river is about 30.5km long, the water supply open channel is about 35.6km long, and the outlet building is 475.0m long. The water supply tunnel adopts a single-hole pressurized water supply scheme, and the cross-section is a circular section with an inner diameter of 7.6m. The water diversion tunnel adopts the combination of "TBM method + drilling and blasting method" construction, of which the shield TBM section is 25.52km long with a lining thickness of 60cm; the open TBM section is 63.99km long with a lining thickness of 50cm; the drilling and blasting section is 38.69km long with a lining thickness of 80cm; the bottom width of the water diversion open channel is 8.0m, the slope coefficient is 3.0, the designed water depth is 2m, and the thickness of the top concrete lining plate of the slope and the bottom plate is 0.05m and 0.06m respectively; the middle layer is paved with a composite geomembrane anti-seepage layer of two cloths and one membrane; and a 0.003-0.005m thick polystyrene foam insulation board is laid under the anti-seepage layer. The riverbed width of the water diversion river is 10m, the slope coefficient is 2.0~3.0, the designed water depth is 2.0m, and the slopes are all natural slopes;

[0120] Combined with the water replenishment demand of the replenishment river, the water diversion flow of the project changes with the water level of the water source area. In a typical flood year, the water diversion period is from May to June, and the water diversion flow is between 175 and 192 m 3 / s; In a typical normal water year, water is not diverted for only a few decades, and the diversion flow rate in other periods is between 170~212m 3 / s; in typical dry years and extremely dry years, water is diverted throughout the year, with the diversion flow rate ranging from 170 to 212m 3 / s (such as Figure 2 shown);

[0121] 2) The water level in the water area where the water intake is located is between 145 and 175m. Measured data show that the monthly surface water temperature in the water area where the water intake is located from 2018 to 2021 was between 12.4 and 26.1℃, 11.9 and 25.7℃, 13.4 and 25.3℃, and 12.3 and 26.9℃, respectively; the reservoir bottom water temperature was between 12.4 and 26.1℃, 11.9 and 25.7℃, 13.4 and 25.3℃, and 12.3 and 26.9℃, respectively; the maximum vertical water temperature gradient was between 0 and 0.034℃ / m, 0℃ / m, 0 and 0.029℃ / m, and 0 and 0.007℃ / m, respectively;

[0122] 3) According to the investigation, the geothermal resources near the water channel are hot springs, namely C1, located on the west side of the water channel, 1.0 km vertically away from the water channel, with a water temperature of 39.5°C at the center; C2, located on the east side of the water channel, 0.8 km vertically away from the water channel, with a water temperature of about 40°C at the center; the equivalent thermal conductivity and heat flux of the geothermal resources are 0.633 W / (m·K) and 41.686 mW / m 2 ;

[0123] 4) After the implementation of a water diversion project, the water flow process upstream of the project water replenishment point changed. According to statistics, the water flow upstream of the water replenishment point in a typical flood year, normal year, dry year and extremely dry year ranged from 298 to 6282 m 3 / s, 277~4348m 3 / s, 277~494m 3 / s and 72~547m 3 / s (such as Figure 3 According to the monitoring results of water quality stations near the water replenishment points, the monthly water temperatures at the water replenishment points from 2015 to 2018 were between 8.4 and 28.5°C, 7.0 and 26.4°C, 9.1 and 24.7°C, and 6.9 and 26.8°C, respectively, and the annual average temperatures were 17.7°C, 18.5°C, 17.7°C, and 15.8°C, respectively (see Figure 2). Figure 4 shown);

[0124] 5) The areas where meteorological factors directly affect the water temperature within the water temperature forecast range are the water supply rivers in the water receiving area. According to the statistical information of the China Meteorological Data Network, five national meteorological stations, B1, B2, B3, B4 and B5, were selected within the water temperature forecast range, and the daily pressure and temperature ranges along the water supply rivers in different typical years were statistically shown in Table 1 below;

[0125] Table 1 Daily pressure and temperature at stations A1, A2, A3, A4, and A5 in different typical years

[0126] ;

[0127] 6) The ecologically sensitive target type of the replenishment river that is more sensitive to water temperature is the aquatic germplasm resource protection area. The river section below the replenishment point of the replenishment river is 652km long, with a water surface width of 400~3000m; the main control stations include HJZ, HZ, XT, etc., with an average annual runoff of 34.7 billion m 3 45.6 billion m 3 39.9 billion m 3. The annual runoff process of the river section has a bimodal feature, and the runoff from May to October during the flood season accounts for about 67.4% of the annual runoff. From the water replenishment point down to the estuary, the aquatic germplasm resources protection area includes the Changchun bream national aquatic germplasm resources protection area, the longnose catfish and yellow catfish national aquatic germplasm resources protection area, the bighead carp national aquatic germplasm resources protection area, the four major carps national aquatic germplasm resources protection area, and a national aquatic germplasm resources protection area. All fish species lay drifting eggs. According to relevant research, the breeding period of fish that lay drifting eggs in the replenishment river is from April to August, mostly from May to July, and the suitable water temperature for breeding is between 16 and 32°C;

[0128] (2) Water temperature prediction along the water transfer channel

[0129] According to the water temperature at the water intake of the water source area, the distribution of geothermal resources and meteorological conditions along the water transmission line, and the water replenishment process in different typical years, the water temperature at the outlet of different water transmission channels in different typical years is calculated. After analysis, the relative error between the water temperature prediction value calculated by the prediction method proposed in the present invention and the measured value is small (as shown in Table 2 to Table 4), indicating that the method proposed in the present invention can be used to simulate the water temperature changes along different water transmission channels. The temperature difference between the end of the water transmission river and the water source area can be up to about 24% (as shown in Table 5, generally when the temperature difference between the end of the water transmission channel and the water source area is less than 20%, the water temperature of the water source area can be used as the boundary condition for predicting the water temperature of the replenishment river and lake), indicating that it is not appropriate to directly use the water temperature of the water source area as the boundary condition for predicting the water temperature of the replenishment river, but the method proposed in the present invention must be used to predict the water temperature along the water transmission channel;

[0130] Table 2 Tunnel outlet temperature prediction

[0131] ;

[0132] Table 3 Temperature prediction at the end of the open channel

[0133] ;

[0134] Table 4 Temperature prediction at the end of the water supply river

[0135] ;

[0136] Table 5 Temperature difference between the end of the water supply river and the water source area

[0137] ;

[0138] (3) Water temperature forecast of the replenishment river in the receiving area

[0139] Since there are fewer water diversion periods in typical flood years, this paper focuses on analyzing the changes in water temperature along the replenishment river after water replenishment in typical normal water years, dry years and extremely dry years. After replenishment, the water temperature at the replenishment point in January-February and November-December is significantly higher than that of the upstream water, and the difference in other months is small (as shown in Table 6). According to calculations, the water temperature along the replenishment river in different months in typical normal water years, dry years and extremely dry years is between 6.48-36.83℃, 6.40-33.12℃ and 8.87-28.27℃ respectively. Among them, the water temperature along the course from April to August was between 15.65~30.81℃, 15.92~31.1℃ and 16.23~28.46℃, and the water temperature along the course from May to July was between 19.72~29.66℃, 20.57~27.63℃ and 20.27~26.20℃ (as shown in Table 7). At present, water temperature monitoring sections are distributed in the river sections of replenishment point-A1, A3-A4, and A4-A5. According to statistics, the difference between the predicted value and the measured value of water temperature is small (as shown in Table 8), indicating that the method proposed in the present invention can be used to simulate the water temperature changes along the course of the water replenishment river in the water receiving area;

[0140] Table 6 Water temperature prediction at water replenishment point

[0141] ;

[0142] Table 7 Monthly average change of water temperature along the replenishment river after water replenishment project Unit: ℃

[0143] ;

[0144] Table 8 Relative difference between the predicted and measured water temperature of the replenishment river after the project replenishment Unit: %

[0145] ;

[0146] (4) Determination of the acceptable degree of water temperature change of ecologically sensitive targets in the water-receiving areas;

[0147] The aquatic germplasm resource protection areas of drifting spawning fish in the mainstream below the project water replenishment point are mainly distributed in the A1-A2, A2-A3, A3-A4 and A4-A5 river sections. Therefore, the focus is on analyzing the acceptability of water temperature changes in the ecologically sensitive targets in the above river sections;

[0148] The water temperature of each river section from April to August in typical normal water years, dry years and extremely dry years is between 17.42 and 31.10℃, which is within the suitable breeding water temperature range. Both were 153, indicating that the daily water temperature did not exceed the suitable breeding water temperature range from April to August after the project was implemented; the degree of change of water temperature of the water ecological protection object All are 1; considering the importance of the water ecological protection object, the acceptable degree of water temperature change in the replenishment river S is determined to be 1 (as shown in Table 9), indicating that the water temperature change caused by the implementation of the project has no impact on the water ecological protection object, and it is determined that the project does not need to carry out stratified water extraction demonstration and design work;

[0149] Table 9 Determination of the acceptability of water temperature changes in ecologically sensitive targets

[0150] ;

[0151] Compared with the time and money spent on studying the changes in water temperature of a river in the receiving area of ​​a water diversion project and its impact on the ecosystem, the present invention only takes about 3 weeks and zero cost to obtain the same conclusion as the prior art method (that is, the water temperature changes caused by the implementation of a water diversion project in this embodiment have no impact on the water ecological protection object), which can save a lot of time (saving about 1 year) and money (saving about 3 million yuan) for the early stage demonstration of the project.

[0152] Comparative test example: In the present invention, the water temperature prediction method along the water conveyance channel under different water conveyance channel combination scenarios and the calculation method for judging the acceptable degree of water temperature change of ecological sensitive targets of rivers and lakes in the water receiving area are both proposed for the first time. The accuracy of the water temperature prediction method along the water conveyance channel under different water conveyance channel combination scenarios has been compared and analyzed with the measured value and the predicted value. It can be seen that the predicted value obtained by the water temperature prediction method along the water conveyance channel under different water conveyance channel combination scenarios of the present invention is highly accurate and basically consistent with the measured value; this comparative test example mainly uses the existing technology to predict the water temperature of the replenishment river. By explaining the time-consuming and cost-consuming characteristics of the existing technology, it reversely verifies the conclusion that the present invention can quickly identify the necessity of stratified water intake at the water intake and has a high judgment accuracy;

[0153] The specific instructions are as follows:

[0154] (1) Existing model methods

[0155] 1) Model Principle

[0156] ①Continuity equation and hydrodynamic equation

[0157] ;

[0158] Where x, y are the longitudinal and transverse coordinates, m; u, v are the vertical average velocity in the longitudinal and transverse directions, m / s; f is the Coriolis coefficient, 1 / s; C Z is Xie Cai coefficient, m 1 / 2 / s;z b is the riverbed elevation, m; τ sx , τ sy are the wind stress on the water surface, A m is the horizontal eddy viscosity coefficient, m 2 / s; S is the source (sink) term, s -1 ; The other symbols are the same as above;

[0159] ②Water temperature equation

[0160] ;

[0161] Where, T is water temperature, °C; E tx , E ty are the diffusion coefficients of water temperature in the x and y directions, m 2 / s; Sφ is the net heat exchange flux obtained by the water flow boundary surface, J / (m 2 ·s); T S is the water temperature source (sink), ℃; the other symbols are the same as above;

[0162] 2) Model construction

[0163] The topography of the river section with a scale of 1:2000 was measured for a 600km section of the replenishment river. The hydrodynamic and water temperature model was input, the calculation grid was divided, the main tributaries were set as source and sink items, and the upstream water level and downstream water level were selected as boundary conditions.

[0164] (2) Calibration of existing models

[0165] The model was calibrated using the daily measured water temperature data of the XY, HZ, SY and QJ hydrological stations in the water replenishment rivers in 2018. Among them, the fluctuation range of the measured water temperature and the simulated water temperature at the XY hydrological station was 0.0~9.3℃, and the fluctuation range of the relative error was 0.36%~41.89%, with the largest difference in August; the fluctuation range of the measured water temperature and the simulated water temperature at the HZ hydrological station was 0.2~6.7℃, and the fluctuation range of the relative error was 0.90%~35.73%, with the largest difference in June; the fluctuation range of the measured water temperature and the simulated water temperature at the QJ hydrological station was 0.1~3.9℃, and the fluctuation range of the relative error was 0.34%~19.33%, with the largest difference in December. Comparing the measured water temperature and simulated water temperature data of the hydrological stations, except for the large relative error in some periods, the simulated water temperature process of each hydrological station is generally consistent with the measured data;

[0166] (3) Verification of existing models

[0167] The model was calibrated using the daily measured water temperatures at the SY and QJ hydrological stations on the replenishment rivers in 2019; the fluctuation range of the measured water temperature at the SY water level station and the simulated water temperature was 0.01~6℃, and the fluctuation range of the relative error was 0.1%~40%, with the largest difference in June; the fluctuation range of the measured water temperature at the QJ hydrological station and the simulated water temperature was 0.2~4℃, with the largest difference in August. The differences between the simulation results and the measured data mainly occurred in the highest and lowest temperatures of the year. In general, the simulation results are close to the actual results, and it can be considered that the model can be used to predict the water temperature of the replenishment rivers;

[0168] (4) Existing model prediction

[0169] The water temperature model with calibration verification is used to predict the monthly water temperature process of a typical normal water year, dry water year and extremely dry water year in a river replenished by a water diversion project.

[0170] After water diversion, in a typical normal water year, the simulated annual average water temperature at the outlet section increased by 1.0℃ compared with the measured value, of which the maximum change value was 2.3℃ in July and the minimum change value was 0.3℃ in January. The water temperature along the river section below the HZ section was the same as before water diversion. In a typical dry year, the annual average water temperature at the outlet section increased by 1.0℃, of which the maximum change value was 2.3℃ in August and the minimum change value was 0.3℃ in January. The water temperature along the river section below the HZ section was the same as before water diversion. In a typical extremely dry year, the annual average water temperature at the outlet section increased by 1.2℃, of which the maximum change value was 2.2℃ in July and the minimum change value was 0.3℃ in January. The water temperature along the river section below the HZ section was the same as before water diversion;

[0171] (5) The comparison between the prior art and the present invention is as follows:

[0172] ① Comparison of basic data requirements

[0173] According to the conditions of use of the calculation method, both the prior art and the present invention require upstream flow and water temperature process data of different typical years of water replenishment points, engineering water replenishment flow and water temperature process data, main tributary flow and water temperature process data and regional meteorological data, but the prior art requires additional topographic data of the water replenishment river section, which costs about 800,000 monitoring funds to obtain; while the method of the present invention does not require topographic data of the water replenishment river section, which saves about 800,000 monitoring funds compared to the prior art;

[0174] ② Comparison of simulation time

[0175] According to the statistics of computational time consumption, under the condition that the basic data is fully prepared, the key links such as modeling, calibration, verification and simulation of the existing technology take about 12 weeks; the present invention only takes 1 week, saving about 92% of the working time compared with the existing technology;

[0176] ③Comparison of simulation effects

[0177] By comparing the water temperature difference along the replenishment river after the existing technology and the implementation of the project of the present invention, it can be seen that the relative deviations of the errors of the existing technology and the present invention in different typical years are small (e.g. Figure 5~Figure 7 As shown, in Figure 5 , Figure 6 and Figure 7 In the figure, water replenishment points-A1, A1-A2, A2-A3, A3-A4, A4-A5 all represent river sections; A1, A2, A3, A4 and A5 respectively represent the upper and lower sections dividing the corresponding river sections), indicating that the prior art and the present invention can be used for water temperature prediction of replenishment rivers and lakes;

[0178] Conclusion: By comparing the above-mentioned prior art with the present invention for the prediction of water temperature in replenishment rivers, it can be seen that, compared with the prior art, the present invention takes less time, can quickly identify the necessity of stratified water intake at the water intake, has high judgment accuracy, and the judgment result is consistent with the result of the prior art using the hydrodynamic water temperature model to construct, calibrate and verify, and saves a lot of money.

[0179] In general, the method for predicting water temperature along the water transfer channel under different water transfer channel combination scenarios and the method for determining the acceptable degree of water temperature change of ecologically sensitive targets of rivers and lakes in the water receiving area are both first-of-its-kind. The present invention achieves the same simulation effect while having the advantages of less data requirements, shorter working time, and higher judgment accuracy compared with the existing technology by simplifying the water temperature prediction method along rivers and lakes.

[0180] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

[0181] Other parts not described belong to the prior art.

Claims

1. A method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project, characterized in that: The following steps are included: Step 1: Collect data on water diversion project parameters and environmental status of water source areas, water diversion areas and receiving areas; Step 2: Prediction of water temperature along the water delivery channel; Based on the water flow and water temperature of the water source area, the heat source and sink data along the water transmission line, and the water temperature calculation models along different water transmission channels and the combination schemes between different water transmission channels, the water temperature along the water transmission channel of the water diversion project is calculated; Step 3: Prediction of water temperature of rivers and lakes in the receiving area; Based on the principle of simple application and short calculation time, the water temperature along the rivers and lakes in the receiving area is calculated by using the water temperature prediction method along the rivers and lakes after water replenishment, taking into account the change of hydraulic retention time of lakes and reservoirs after water replenishment. Step 4: Determine the acceptable degree of water temperature change of ecologically sensitive targets of rivers and lakes in the water receiving area; Based on the calculation results of water temperature of replenished rivers and lakes, by calculating the statistical values ​​of water temperature changes and the acceptability of water temperature changes for the ecological protection objects of replenished rivers and lakes, and according to the judgment standards for the acceptability of water temperature changes for the ecological protection objects of replenished rivers and lakes, it is judged whether it is necessary to carry out stratified water intake demonstration and design work for the water diversion project water intake.

2. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 1 is characterized in that: In step 1, the water diversion project parameters and the environmental status data of the water source area, water diversion area and water receiving area include: Project water replenishment flow data at different periods in different typical years; Project water intake parameters, including the shape, size and bottom plate elevation data of the water intake; The type of water channel, including the length, cross-sectional dimensions and base elevation data of the water channel; Water temperature data of different water levels and depths at the project water intake area in different periods over the past three years; The types of geothermal resources distributed along the water transfer channel, the temperature at the center of the geothermal resource, the vertical distance from the center of the geothermal resource to the water transfer channel, and the equivalent thermal conductivity and heat flux density of the geothermal resources; The upstream inflow flow of the replenishment points of the replenishment rivers and lakes, and the water temperature data along the replenishment rivers and lakes at different times in the past three years; Meteorological data of air pressure and temperature at water source areas, water delivery channels, and water replenishment river and lake meteorological stations at different periods in the past three years; Replenish water to sensitive ecological targets of rivers and lakes and the water temperature requirements for reproduction and growth.

3. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 1 or 2, characterized in that: In step 2, the water delivery channels include water delivery rivers and lakes, water delivery tunnels, and water delivery open channels; The calculation method of water temperature along the water supply river and lake is as follows: Considering the flow characteristics of water-carrying rivers and lakes, assuming that the water-carrying rivers and lakes are evenly mixed along the cross section, the water-carrying rivers and lakes are divided into River and lake section Water temperature at outlet time t The calculation is as follows: (1) In the formula, Segmentation of water channels Inlet water temperature, °C; Segmentation of water channels Length, m; Segmentation of water channels Average flow velocity, m / s; , and Divide rivers and lakes into sections for water delivery Calculation coefficient of ; For numbering; (2) (3) (4) (5) In the formula, is the density of water, kg / m 3 ; is the specific heat of water, J / (kg·℃); Segmentation of water channels Lateral inflow per unit river length, m 2 / s; Segmentation of water channels Water temperature of the side inflow, ℃; Divide rivers and lakes into sections for water delivery Section width, m; Segmentation of water channels Local atmospheric pressure, hPa; Segmentation of water channels Atmospheric temperature, °C; Segmentation of water channels Air-water convection heat exchange coefficient, W / (m 2 ℃); Segmentation of water channels The speed of the atmosphere relative to the water flow, m / s; , , Divide rivers and lakes into sections for water delivery Calculation parameters of , , Segmentation of water channels Calculated variables of is the water temperature at the starting point of the water-conveying river-lake section at time t, which is closely related to the flow and temperature of the water from the upstream of the water-conveying river-lake section and the water source area, and is expressed as: (6) In the formula, , They are the water from the upstream of the river and lake section and the water from the water source area, m 3 / s; , are the water temperatures of the upstream water from the water supply river and lake section and the water source area, ℃; , They are , Density of water at temperature, kg / m 3 ; , They are , Constant pressure hot melt at temperature, kJ / (kg℃).

4. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 3 is characterized in that: In step 2, water transfer tunnels are divided into two types: pressure tunnels and non-pressure tunnels. The water temperature along the tunnel is calculated as follows: (1) Pressurized tunnel: Considering the temperature transfer between water flow and rock medium in the water conveyance tunnel, the tunnel is divided into Section, hole section Water temperature at outlet time t The calculation is as follows: (7) In the formula, Segmentation of water channels Flow rate, m 3 / s; Segmentation of water channels Length, m; and Segmentation of pressurized tunnels Calculate the parameters, expressed as , ,in, For the tunnel The inner diameter of the tunnel, m; For the tunnel The water temperature of the constant temperature layer, ℃; Segmentation of pressurized tunnels Heat exchange coefficient between water and tunnel, W / (m 2 ℃); (8) (9) In the formula, For the tunnel The outer diameter of the tunnel lining, m; For the tunnel The outer diameter of the temperature change layer is 2~3 times of, m; and The tunnel sections Thermal conductivity of lining and thermal conductivity of surrounding rock temperature-varying layer, W / (m·℃); For the tunnel Height of ground point above sea level, m; For the tunnel Temperature at the center of geothermal resources, °C; For the tunnel Distance from geothermal center to water delivery channel, m; For the tunnel Equivalent thermal conductivity of geothermal resources, W / (m·℃); For the tunnel Geothermal resource heat flux, W / m 2 ; (2) Pressureless tunnel: Pressureless tunnel is connected to the atmosphere. The change of water temperature along the pressureless tunnel is related to the temperature transfer process between rock medium and atmosphere. Water temperature at outlet time t The calculation is as follows: (10) (11) (12) (13) in, For the tunnel Tunnel bottom width, m; Segmentation of water channels Water flow area, m 2 ; Segmentation of unpressured tunnels Heat exchange coefficient between water and tunnel, W / (m 2 ℃); For the tunnel Thickness of lining vertical wall or base plate, m; For the tunnel The thickness of the surrounding rock temperature change layer is the diameter of the hole. 1~2 times of, m; For the tunnel Wet perimeter, m; , and Segmentation of unpressured tunnels Calculation coefficient of ; , , Segmentation of unpressured tunnels Calculation parameters.

5. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 4 is characterized in that: In step 2, the water temperature along the open channel is calculated as follows: The water temperature of the water delivery channel is related to the air temperature, the structure and length of the open channel; the water delivery channel is divided into When the temperature When the water temperature at the outlet of channel section i at time t is less than -10℃, It is expressed as: (14) (15) (16) (17) (18) (19) In the formula, For channel section Water surface width, m; Divide the open channel into sections Heat exchange coefficient, W / (m 2 ℃); Divide the open channel into sections Equivalent heat exchange coefficient between water body and channel bed, W / (m 2 ℃); Divide the open channel into sections Equivalent ground temperature of the channel bed, ℃; Divide the open channel into sections Average ground temperature of the subgrade under the channel floor, °C; Divide the open channel into sections Average ground temperature of the slope substratum, °C; Divide the open channel into sections The heat exchange coefficient between the water body and the channel is used to calculate the heat exchange coefficient between the water body and the slope , heat exchange coefficient between water and bottom plate ,W / (m 2 ℃); Divide the open channel into sections The wet week, The bottom of the canal is wet. is the wetted perimeter of the channel slope, , m; Divide the open channel into sections The number of layers of the slope or channel bottom cross-section structure; Indicates the water channel segmentation Middle slope or channel bottom Thickness of the layer, m; Indicates the water channel segmentation Middle slope or channel bottom Thermal conductivity of the layer, W / (m 2 ℃); , For temperature Open channel segmentation for water supply when <-10℃ Calculation parameters of When the temperature ≥-10℃, channel section Water temperature at outlet time t It is expressed as: (20) (21) (22) In the formula, , and Divide the open channel into sections Calculation coefficient of ; , , For temperature ≥-10℃ water delivery open channel segmentation Calculation parameters of =0.158×10 -3 p a .

6. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 5, characterized in that: In step 3, the water replenishment rivers and lakes in the water receiving area include replenishment rivers and replenishment lakes and reservoirs. The water temperature calculation method of the replenishment rivers and replenishment lakes and reservoirs in the water receiving area is as follows: The water temperature forecast range of the replenishment rivers in the water receiving area includes the river section below the replenishment point to the estuary, and the replenishment rivers are divided into Section, water supply river section of the receiving area Water temperature at the end time t The calculation is as follows: (23) In the formula, Divide the river into sections for water replenishment Water temperature at the starting end, °C; Divide the river into sections for water replenishment Length, m; Divide the river into sections for water replenishment Average flow velocity, m / s; , and Divide the river into sections for water replenishment Calculation coefficient of ; For numbering; (24) (25) (26) (27) In the formula, is the density of water, kg / m 3 ; is the specific heat of water, J / (kg·℃); Divide the river into sections for water replenishment Lateral inflow per unit river length, m 2 / s; Divide the river into sections for water replenishment Water temperature of the side inflow, ℃; Divide the river into sections for water replenishment Average section width, m; Divide the river into sections for water replenishment Local atmospheric pressure, hPa; Divide the river into sections for water replenishment Atmospheric temperature, °C; Divide the river into sections for water replenishment Air-water convection heat exchange coefficient, W / (m 2 ℃); Divide the river into sections for water replenishment The speed of the atmosphere relative to the water flow, m / s; , , Divide the river into sections for water replenishment Calculation parameters of is the water temperature at the starting end of the replenishment river at time t, which is closely related to the flow rate and temperature of the upstream water of the replenishment river and the replenishment point at the end of the water transfer channel, and is expressed as: (28) In the formula, , The water from the upstream of the replenishment point of the replenishment river and the replenishment point at the end of the water transfer channel are respectively, m 3 / s; , are the water temperatures of the upstream water from the water supply river and lake section and the replenishment point at the end of the water supply channel, ℃; , They are , Density of water at temperature, kg / m 3 ; , They are , Constant pressure hot melt at temperature, kJ / (kg℃); according to different water delivery channel combination schemes, is the water temperature at the outlet of the last type of water delivery channel at time t, i.e., the water delivery river, lake, tunnel or open channel segment in step 2 The calculated value at time t; After the implementation of the water diversion project, the water temperature of the water supply lakes and reservoirs in the receiving area is affected by the inflow and water temperature conditions of the basin, the water supply volume and water temperature conditions: When the hydraulic retention time of the water supply lakes and reservoirs in the receiving area is less than or equal to 14 days after the water diversion project is implemented, the prediction method of the water temperature impact of the water supply lakes and reservoirs in the receiving area is the same as the prediction method of the water temperature of the water supply river; When the water diversion project is implemented, the hydraulic retention time of the water supply lake in the receiving area is greater than 14 days. tributaries into the lake, the water temperature at any point in the water area of ​​the lake is It is expressed as: (29) In the formula, , The water inflow within the reservoir catchment area and the water replenishment at the end of the water delivery channel are respectively, m 3 / s; , They are the water temperatures of the tributaries within the reservoir catchment area and the replenishment water temperature at the replenishment point at the end of the water transfer channel, ℃; , They are , Density of water at temperature, kg / m 3 ; , They are , Constant pressure hot melt at temperature, kJ / (kg℃); according to different water delivery channel combination schemes, is the water temperature at the outlet of the last type of water channel at time t, i.e., the water temperature of the river, lake, tunnel or open channel segment in step 2. The calculated value at time t.

7. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 6 is characterized in that: In step 4, the calculation method for the statistical value of water temperature change of the ecological protection objects of rivers and lakes in the water receiving area is as follows: Divide the replenished rivers and lakes into Section, with water replenishment river and lake sections There are H water ecological protection objects distributed in the During the sensitive period , The upper and lower limits of the suitable temperature are and , Statistical value of water temperature change at time t It is expressed as: (30) (31) In the formula, t is At the time of analysis, a full calendar year is sorted from 1 to 365 days, then 1≤ ≤365; for Water supply river and lake segment The terminal temperature at the tth moment, °C; Water ecological protection objects Water temperature change statistics It is expressed as: (32)。 8. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 7, characterized in that: In step 4, the method for calculating the acceptable degree of water temperature change of the ecological protection objects of the rivers and lakes in the water receiving area is as follows: Statistics of water replenishment for rivers and lakes The total number of water ecological protection objects in the river sections is , the acceptable degree of water temperature change of water ecological protection objects in replenished rivers and lakes The degree of change in water temperature of water ecological protection objects of replenished rivers and lakes 2. Importance of water ecological protection objects Related, expressed as: (33) Degree of change in water temperature of water ecological protection objects It indicates the ratio of the total number of analysis periods that meet the water temperature requirements during the sensitive period after the water temperature changes to the total length of the sensitive period, expressed as: (34) In the formula, when When the value is 1, it means that the water temperature change has an impact on the water ecological protection object. No effect; when When the value is 0.7, it means that the water temperature change has an impact on the water ecological protection object. Causes minor impact; when When the value is 0.4, it means that the water temperature change has a great impact on the water ecological protection object. Cause a greater impact; when When the value is 0.1, it means that the water temperature change has an impact on the water ecological protection object. Cause serious impact; Importance of water ecological protection objects and protection levels of water ecological protection objects About, The importance of each water ecological protection object It is expressed as: (35) In the formula, when =1, the water ecological protection object is the endangered species or above listed in the Red List of Endangered Animals of China, the Red List of Biodiversity of China or the IUCN List; =2, the objects of water ecological protection are species listed in the national and local key protected wild animals and plants list; =3, the objects of water ecological protection are rare, unique or important aquatic germplasm resources; =4, the objects of water ecological protection are other species with important ecological, scientific and social values ​​and in need of protection.

9. The method for determining the necessity of stratified water intake at a water intake of a water diversion and regulation project according to claim 8, characterized in that: In step 4, the criteria for determining the acceptable degree of water temperature changes for water ecological protection objects in the water-receiving area are as follows: Acceptable degree of water temperature change of water ecological protection objects in water-replenishing rivers and lakes in the water receiving area It is the overall acceptability of water temperature changes for multiple water ecological protection objects, referring to the water temperature change degree of water ecological protection objects. Take value, when When it is less than or equal to 0.7, the water intake of the water diversion project needs to carry out in-depth demonstration and design work on stratified water intake; otherwise, there is no need to carry out demonstration and design work on stratified water intake.

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