Farmland irrigation area open channel water quantity management system

Abstract

The invention discloses a farmland irrigation area open channel water volume management system, and relates to the field of farmland water conservancy, the farmland irrigation area open channel water volume management system comprises a cloud control platform, a water level detection sensor and a gate mechanism, the cloud control platform controls the flashboard assembly to open the corresponding opening degree according to transmitted surge data and the water level difference between the upstream and the downstream of the gate mechanism after water drainage is finished, water is supplemented under the condition of minimum water energy loss, the total water drainage reduction amount caused by surge is supplemented, sufficient irrigation and drainage water is achieved, and the irrigation and drainage efficiency is improved. The water flow is divided during water drainage, so that the water flow is drained to two sides, the concentrated water flow is divided into two strands, the local impact force to the downstream is reduced, the loss of the total water amount in the water drainage process can be effectively avoided, the water used in an irrigation area keeps the optimal water amount and is not too much or too little, the water drainage efficiency is high, and the water drainage effect is good. And some emergencies can be effectively handled.

Description

Technical Field

[0001] The invention relates to the field of farmland water conservancy, and in particular to an open channel water volume management system for a farmland irrigation area. Background Art

[0002] When irrigation is needed in farmland irrigation areas, the upstream open channel usually opens the gate to release water, and the amount of water released is determined by the demand of farmland in the downstream irrigation area. In order to avoid excessive surges, the gate opening needs to be controlled step by step each time the gate is opened to release water. This not only greatly affects the efficiency of water release, but also some surges will still occur downstream in this case, resulting in a loss of total water release; When emergency water is needed in farmland irrigation areas, the traditional step-by-step controlled opening of gates will result in very low water release efficiency. Moreover, traditional gates are opened up and down. Once the gates are opened directly to release water, the strong water flow will not only impact the gates and damage them, but also impact the open channels downstream, causing damage to the structure of the downstream open channels. At the same time, a large number of surges will be generated, resulting in a reduction in the total water release, which in turn affects the irrigation downstream. Summary of the invention

[0003] The purpose of the present invention is to provide an open channel water management system for farmland irrigation areas, which can avoid the loss of total water release while achieving efficient water release, and at the same time greatly reduce the scouring of the downstream open channel by water flow, so as to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an open channel water volume management system for farmland irrigation areas, comprising a cloud control platform, a water level detection sensor and a gate mechanism, wherein the water level detection sensor is respectively installed at the upstream and downstream of the gate mechanism, and the gate mechanism comprises a gate assembly for controlling the upstream water release rate and diverting the released water flow, and the gate assembly is provided with a flow baffle assembly for controlling the reduction of the upstream water release potential energy according to the downstream water flow speed, the water level detection sensor monitors the water level changes upstream and downstream in real time, and collects the data of the downstream surge during the water release process, and the cloud control platform controls the gate assembly to open the corresponding opening degree according to the transmitted surge data and the water level difference between the upstream and downstream of the gate mechanism after the water release is completed, replenishes water with minimum water energy loss, and makes up for the total water release reduction caused by the surge, so as to achieve sufficient drainage and irrigation water volume.

[0005] Preferably, the gate plate assembly comprises a main frame and two gate plates, the two gate plates are triangularly mounted on the lower end surface of the main frame, the two gate plates are hinged to each other near the triangular ends, the rear end of each gate plate is rotatably connected to a tail plate portion, the upper end of the tail plate portion is slidably mounted on the lower end surface of the main frame, and each tail plate portion is respectively mounted with an opening and closing connection piece, and the opening and closing connection piece is controlled to move toward the center direction of the main frame by a controllable power source, the two gate plates are close to each other, the opening distance between the tail plate portion and the vertical plate portion on the main frame is the opening degree of the gate, and the upstream water flow diverts the water flow flowing into the downstream through the two gate plates, and guides the openings on both sides to release water.

[0006] Preferably, the flow baffle assembly includes a float and a plurality of water baffles, an inner concave cavity is arranged on the front end face of the gate plate, a notch is arranged on the upper end face of the gate plate at the position of the inner concave cavity, a rotating shaft is rotatably installed in the notch and passes through the inner concave cavity, each of the water baffles is fixedly installed on the rotating shaft, a gear is fixedly connected to the rotating shaft, a slide groove cavity is connected in the notch, a rack is slidably installed in the slide groove cavity, the rack is meshed with the rotating shaft, a compression spring is connected between one end of the rack and the inner side wall of the slide groove cavity, and a steel wire rope is fixedly connected between the other end and the float, the float is placed in the downstream water flow and is subjected to the impact force of the water flow, and the rack is pulled to drive the water baffle to flip and open, and the magnitude of the water flow impact force is proportional to the flip-open angle of the water baffle.

[0007] Preferably, the opening and closing connecting piece includes a connecting block fixedly mounted on the tail plate portion, a connecting rod is hinged on the connecting block, a servo motor is fixedly mounted on the upper end surface of the main frame, a lead screw is fixedly connected to the output end of the servo motor, a threaded sleeve is threadedly connected to the lead screw, the connecting rod and the threaded sleeve are hinged, and the cloud control platform issues an opening command to control the number of rotations of the lead screw to control the moving distance of the tail plate portion.

[0008] Preferably, the water baffle is arranged in an arc shape, and the width of the water baffle gradually increases from top to bottom.

[0009] Preferably, water contact plates are installed on both sides of the float.

[0010] Preferably, the method for replenishing the water loss caused by downstream surge specifically comprises the following steps: S1: Send a water release command to the cloud control platform based on the downstream water demand. The cloud control platform controls the gate to open and discharge the theoretical water volume within time T; S2: Using a water level detection sensor to detect the number and height of the surge waves generated downstream within a time T, the cloud control platform calculates the actual water release volume based on the collected surge data, the gate data when the water is released, and the initial water levels of the upstream and downstream, thereby obtaining the loss of water release volume △V caused by the surge; S3: After obtaining the lost water release volume, the gate opening is dynamically controlled to replenish water according to the upstream and downstream water level data before replenishment, and the gate opening is synchronously changed according to the upstream and downstream water level difference changes to complete water release and replenishment in the shortest time while minimizing the loss of water energy.

[0011] Preferably, the method for detecting the number and height of the swells generated downstream comprises the following steps: First, the static water level data at least ten minutes before the gate is opened to release water is extracted as a benchmark; Secondly, the minimum peak height threshold is set to control the sampling frequency, the number of surges is identified through peak detection, and finally the surge height is calculated by calculating the difference between each peak and its adjacent trough, and the maximum, average and standard deviation are recorded in time series.

[0012] Preferably, the specific method for obtaining the loss of water discharge ΔV comprises the following steps: Q1: Add a correction coefficient to the average surge height as the amplitude of the downstream water level fluctuation due to the surge, and use the water level data of the downstream water level and the amplitude of the fluctuation to obtain the instantaneous value of the downstream water level; Q2: The difference between the monitored upstream water level data and the instantaneous value of the downstream water level is used as the effective water head, and then the instantaneous flow is obtained by using the opened gate parameters and the effective water head; Q3: The instantaneous flow rate is numerically integrated within time T to obtain the actual water release volume. The difference between the theoretical water release volume and the actual water release volume is the loss water release volume △V.

[0013] Preferably, the dynamic control of the gate opening in step S3 specifically includes the following method: The water replenishment flow rate per unit time is calculated using the lost water discharge volume △V and the water replenishment time set according to demand. It is only necessary to maintain the water replenishment flow rate unchanged, and adjust the gate opening according to the water level difference between upstream and downstream. When the water level difference between upstream and downstream gradually decreases, the gate opening is gradually expanded.

[0014] In summary, the beneficial effects of the present invention are: 1. The present invention performs diversion through the triangular ends formed by two gate plates, so that the water flow is discharged to both sides, and the concentrated water flow is divided into two streams, thereby reducing the local impact force on the downstream, avoiding damage to the structure of the downstream open channel caused by concentrated scouring, and the water flow velocity distribution is more uniform after diversion, reducing the continuous erosion of high-speed water flow on specific areas, and extending the life of water conservancy facilities. At the same time, the triangular ends formed by the two gate plates guide the water flow to turn smoothly, reduce the generation of turbulence and harmful vortices, thereby reducing energy loss and improving water flow efficiency; 2. When discharging water from the upstream, if the water flow speed in the downstream is too fast, the water baffle will flip open and the water flow will impact the water baffle. The curvature of the water baffle will guide the water flow to form a certain collision with the other positively discharged water flow, thereby reducing the upstream water flow and avoiding excessive flow speed of the downstream water flow; 3. When releasing water, you can ignore the gradual opening of the gate and directly open the opening of the corresponding gate to release water in the fastest and most efficient way. After the release, the lost water is replenished by dynamically controlling the corresponding opening of the gate assembly according to the detected surge data and the water level difference between the upstream and downstream. In this way, combined with the previous efficient release method, the actual required water release can be completed in the shortest time, and the loss of total water volume during the release process can be effectively avoided. Compared with the uncertainty of water volume caused by the opening time of the traditional delayed gate, it effectively guarantees the total water supply to the downstream, keeps the water use in the irrigation area at the optimal level, neither too much nor too little, and has high release efficiency, which can effectively deal with some emergencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the invention or the technical solutions in 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a schematic diagram of the overall structure of an open channel water volume management system for a farmland irrigation area according to the present invention; Figure 2 It is a structural schematic diagram of a gate mechanism in an open channel water volume management system for a farmland irrigation area according to the present invention; Figure 3 It is a schematic diagram of the top view of the gate mechanism in an open channel water volume management system for a farmland irrigation area according to the present invention; Figure 4 It is a schematic diagram of a gate mechanism in an open channel water volume management system for a farmland irrigation area from a rear view perspective of the present invention; Figure 5It is a schematic diagram of the position structure of the component fixing blocks of the gate mechanism in an open channel water volume management system for farmland irrigation areas according to the present invention; Figure 6 It is a schematic diagram of the gate plate structure of a gate mechanism in an open channel water volume management system for farmland irrigation areas according to the present invention; Figure 7 It is a schematic diagram of the gate plate structure of a gate mechanism in an open channel water volume management system for farmland irrigation areas according to the present invention; Figure 8 The present invention is a schematic diagram of the open structure of a water retaining plate of a gate mechanism in an open channel water volume management system for a farmland irrigation area.

[0017] The symbols in the accompanying drawings are described as follows: gate mechanism 1; water level detection sensor 2; downstream water channel 3; upstream water channel 4; main frame 10; servo motor 11; gate plate 12; tail plate part 13; notch 14; rotating shaft 15; gear 16; rack 17; slide groove cavity 18; inner concave cavity 19; water baffle 20; connecting block 21; screw 22; connecting rod 23; threaded sleeve 24; wire rope 25; float 26; water contact plate 27; fixing block 28. DETAILED DESCRIPTION

[0018] The present invention will now be further described in detail in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic way, and therefore they only show the structures related to the present invention.

[0019] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0020] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0021] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0022] In the present invention, unless otherwise clearly defined and specified, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of at least two elements or the interaction relationship between at least two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Combine the following Figure 1-8 The present invention is described in detail. An embodiment of the present invention is: an open channel water management system for a farmland irrigation area, comprising a cloud control platform, a water level detection sensor 2 and a gate mechanism 1. The water level detection sensor 2 is respectively installed in an upstream water channel 4 and a downstream water channel 3 to detect water level data of the upstream and downstream, and the gate mechanism 1 is installed between the upstream water channel 4 and the downstream water channel 3 to control the discharge of water from the upstream to the downstream. Since surges are generated downstream when the gate is opened to release water, and the surges affect the amount of water released, resulting in a decrease in the amount of water released, the water level detection sensor 2 is used to monitor the water levels of the upstream and downstream, and the data of the downstream surges during the water release process are collected, and the data are transmitted to the cloud control platform. After the water release is completed, the cloud control platform controls the gate assembly to open a corresponding opening according to the transmitted surge data and the water level difference between the upstream and downstream of the gate mechanism 1, replenishes water with minimum water energy loss, and replenishes the total reduction in water release caused by the surge, so as to achieve sufficient drainage and irrigation water.

[0024] It is worth mentioning that, in the present embodiment, the gate mechanism 1 includes a gate assembly which controls the upstream water discharge rate and diverts the discharged water flow. The flow rate of the upstream water discharge is controlled by controlling the opening degree of the gate assembly. The gate assembly is provided with a flow blocking assembly which controls the reduction of the upstream water discharge potential energy according to the downstream water flow speed. Once the downstream water flow speed is too fast during water discharge, the flow blocking assembly will be driven to partially guide the upstream water flow back, thereby forming a water flow impact upstream to limit the speed.

[0025] It should be noted that, in this embodiment, the gate assembly includes a main frame 10 and two gate plates 12, the main frame 10 is installed across the canal, and the two gate plates 12 are installed in a triangular shape on the lower end surface of the main frame 10, the two gate plates 12 are hinged to each other near the triangular ends, so that the triangular ends of the two gate plates 12 can divert the water flow, and the rear end of each gate plate 12 is rotatably connected to a tail plate portion 13, and the upper end of the tail plate portion 13 is slidably installed on the lower end surface of the main frame 10, so that when the tail plate portion 13 slides open, the triangular ends of the two gate plates 12 will move in the upstream direction, and at the same time, the angle of the triangular end becomes smaller, so that the larger the opening, the more obvious the effect of diverting the water flow to both sides; An opening and closing connection piece is respectively installed on each of the tail plate parts 13, and the opening and closing connection piece is controlled by a controllable power source to move toward the center direction of the main frame 10. The two gate plates 12 are close to each other, and the opening distance between the tail plate part 13 and the vertical plate part on the main frame 10 is the opening degree of the gate. The upstream water flow is diverted to the water flow flowing into the downstream through the two gate plates 12, and is guided to the openings on both sides for water release.

[0026] The opening and closing connection member includes two connecting blocks 21 fixedly mounted on the tail plate portion 13, each of the connecting blocks 21 is hinged with a connecting rod 23, the upper end surface of the main frame 10 is fixedly mounted with a servo motor 11, the output end of the servo motor 11 is fixedly connected with a lead screw 22, a threaded sleeve 24 is threadedly connected to the lead screw 22, the connecting rod 23 is hinged with the corresponding threaded sleeve 24, when the lead screw 22 rotates clockwise, the threaded sleeve 24 located on the upper side is driven to move upward, and the threaded sleeve 24 located on the lower side is driven to move downward, so that the up and down movement of the threaded sleeve 24 is used to drive the opening and closing of the tail plate portion 13, and the cloud control platform issues an opening command to control the number of rotations of the lead screw 22 to control the moving distance of the tail plate portion 13.

[0027] In addition, in one embodiment, the flow blocking assembly includes a float 26 and a plurality of water baffles 20, an inner concave cavity 19 is provided on the front end surface of the gate plate 12, a notch 14 is provided on the upper end surface of the gate plate 12 at the position of the inner concave cavity 19, a rotating shaft 15 is rotatably installed in the notch 14 and penetrates into the inner concave cavity 19, each of the water baffles 20 is fixedly installed on the rotating shaft 15, a gear 16 is fixedly connected to the rotating shaft 15, a chute cavity 18 is connected in the notch 14, a rack 17 is slidably installed in the chute cavity 18, the rack 17 is meshed with the rotating shaft 15, a compression spring is connected between one end of the rack 17 and the inner side wall of the chute cavity 18, and a wire rope 25 is fixedly connected between the other end and the float 26, the wire rope 25 is fixedly guided on the gate plate 12 by a fixing block 28, and at the opening of the chute cavity 18, a gear 16 is fixedly connected to the chute cavity 18. A guide column is provided, and the float 26 is placed in the downstream water flow to be impacted by the water flow, and the rack 17 is pulled to drive the water baffle 20 to flip and open. The magnitude of the water flow impact force is proportional to the angle at which the water baffle 20 is flipped and opened. Since the water flow velocity at the bottom of the canal is lower than the water flow velocity on the surface, the width of the water baffle 20 gradually increases from top to bottom, which is convenient for opening the water baffle 20. At the same time, the water baffle 20 can be set to be arc-shaped. After the water baffle 20 is flipped and opened, the water flow impacts the water baffle 20. The curvature of the water baffle 20 guides the water flow to form a certain collision with the rest of the positively discharged water flow, thereby reducing the upstream water flow and avoiding excessive downstream water flow velocity. At the same time, in order to allow the float 26 to better contact the water flow effect, water contact plates 27 are respectively installed on both sides of the float 26. The water contact plates 27 can be arc-shaped, which has a better effect of sensing the water flow velocity.

[0028] When it is necessary to open the gate to release water, the cloud control platform receives the water release instruction, controls the servo motor 11 to start, and uses the rotation of the lead screw 22 to drive the threaded sleeve 24 to move up and down, thereby pulling the tail plate part 13 to slide toward the center of the main frame 10, so that the gate opens to a corresponding opening degree b, and the left and right gate plates 12 are opened by a distance of b / 2. The upstream water flow is diverted by the triangular ends formed by the two gate plates 12, so that the water flow is discharged to both sides, dividing the concentrated water flow into two streams, reducing the local impact force on the downstream, and avoiding damage to the structure of the downstream open channel due to concentrated scouring. After diversion, the water flow velocity distribution is more even, reducing the continuous erosion of high-speed water flow on specific areas, and extending the life of water conservancy facilities. The triangular ends formed by the two gate plates 12 guide the water flow to turn smoothly, reduce the generation of turbulence and harmful vortices, thereby reducing energy loss and improving water flow efficiency. Moreover, when discharging water upstream, if the water flow speed downstream is too fast, it will impact the float 26, so that the float 26 is subjected to the impact force of the water flow and pulls the steel wire rope 25 downstream, thereby driving the rack 17 to slide, so that the water baffle 20 is flipped open, and the flipping and opening angle of the water baffle 20 is proportional to the magnitude of the water flow impact force. After the water baffle 20 is flipped open, the water flow impacts the water baffle 20, and the curvature of the water baffle 20 guides the water flow to form a certain collision with the rest of the water flow discharged in the forward direction, thereby reducing the upstream water flow and avoiding excessive flow rate of the downstream water flow.

[0029] When the gate is opened to release water to the downstream, surge waves will appear in the downstream, and the formation of surge waves will cause the total water release within a period of time to decrease. The traditional method is to control the gradual opening of the gate to reduce the formation of surge waves downstream. This method has low uneven drainage efficiency and cannot cope with the situation where water is needed. In addition, there will still be certain surge waves that cause the total water release to decrease, causing deviations in the downstream water demand, affecting the growth of crops in the irrigation area. For this reason, the present invention also proposes a method for replenishing the lost water release caused by surge waves when the gate is opened to release water, so that the gradual opening of the gate can be ignored when releasing water, and the opening degree of the corresponding gate can be opened to release water in the fastest and most efficient way. After the release is completed, the lost water release volume is replenished by dynamically controlling the gate assembly to open the corresponding opening degree according to the detected surge data and the water level difference between the upstream and downstream, thereby ensuring the total water supply to the downstream and maintaining the optimal water volume in the irrigation area.

[0030] The specific method includes the following steps: first step: The water level detection sensor 2 installed in the upstream and downstream open channels is used to monitor the upstream and downstream water levels in real time. When the gate is opened to release water, the theoretical water release volume must be discharged within time T according to the demand. First, the static water level data at least ten minutes before the downstream gate is opened to release water is extracted as a benchmark. After the gate is opened to release water, the water level detection sensor 2 located downstream captures transient fluctuations at a sampling frequency of 20Hz, sets the minimum peak height threshold, and identifies the number of surges through peak detection; Finally, the difference between each crest and its adjacent trough is calculated to calculate the surge height, and the maximum, average and standard deviation are recorded in time series; Statistics output: Surge times: the number of fluctuation events exceeding the threshold per unit time; Swell height: record the maximum, average and standard deviation in time series.

[0031] At the same time, the upstream and downstream water level detection sensors 2 synchronously transmit the water level data when the water is released to the cloud control platform, and the cloud control platform calculates the actual water release volume according to the opening degree b of the gate when the water is released, thereby obtaining the loss of water release volume △V caused by the surge; First, the downstream water level fluctuates due to the surge, causing the effective water head H(t) to change over time. H(t)=h(t) 上游 -h(t) 下游 ; The downstream water level fluctuates due to the presence of surges. After testing, a correction coefficient k is added to the average surge height obtained downstream. The value of k is between 0.6 and 0.8, which is the amplitude of the downstream water level fluctuation due to surges. The correction coefficient k is related to the width of the channel upstream and downstream of the gate. The larger the width ratio of the upstream and downstream channels, the larger the value of k, so that h(t) 下游 There is a fluctuating water level change value, so the final H(t)=h(t) 上游 -h(t) 下游 -k*mean swell height; So the actual flow is:

[0032] : Flow coefficient (related to gate type, such as 0.6~0.7 for flat gate); b is: the opening degree of the gate; h is: the height of the water level when flowing through the gate; g is: acceleration due to gravity.

[0033] Therefore, the actual water release volume is obtained by numerically integrating the instantaneous flow rate within time T.

[0034] The loss of water discharge △V is the theoretical water discharge minus the actual water discharge.

[0035] Step 2: After obtaining the lost water volume △V, the water release time can actually be reasonably extended according to the lost water release to replenish this part of the water volume. However, during the extended water release time, surges will still occur, making the final water release volume always have a certain difference. Therefore, the most efficient water release should be selected when the gate is opened for the first time, and the water energy loss should be minimized when replenishing water later, so as to perfectly compensate for the loss during the first water release, thereby achieving a closed loop of effect. After obtaining the lost water discharge volume △V, the gate opening is dynamically controlled to replenish water according to the upstream and downstream water level data before water replenishment, so as to complete water discharge and replenishment in the shortest time while minimizing the loss of water energy. The water replenishment flow per unit time is calculated using the lost water discharge volume △V and the water replenishment time set according to demand. There is no surge during water replenishment, so H(t) = the upstream and downstream water level difference, and the upstream and downstream water level difference will not be very large after the water discharge is completed; Therefore, the water replenishment flow rate is:

[0036] It is only necessary to maintain the water replenishment flow rate unchanged, and adjust the gate opening b according to the water level difference between upstream and downstream. When the water level difference between upstream and downstream gradually decreases, gradually expand the gate opening to carry out the most efficient water replenishment while maximizing the reduction of water energy loss during water replenishment.

[0037] Therefore, combined with the previous efficient water release method, the water release volume actually required can be completed in the shortest time, and the loss of total water volume during the water release process can be effectively avoided. Compared with the uncertainty of water volume caused by the opening time of the traditional delayed gate, the present invention effectively guarantees the total water supply to the downstream, so that the irrigation area can maintain the optimal water volume, neither too much nor too little, and the water release efficiency is high, which can effectively deal with some emergencies.

[0038] The above is only a specific implementation of the invention, but the protection scope of the invention is not limited to it. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the invention. Therefore, the protection scope of the invention should be based on the protection scope defined in the claims.

Claims

1. An open channel water volume management system for a farmland irrigation area, comprising a cloud control platform, a water level detection sensor (2) and a gate mechanism (1), wherein the water level detection sensor (2) is respectively installed upstream and downstream of the gate mechanism (1), and is characterized in that: The gate mechanism (1) comprises a gate assembly capable of controlling the upstream water discharge rate and diverting the discharged water flow, the gate assembly being provided with a flow blocking assembly capable of reducing the upstream water discharge potential energy according to the downstream water flow speed control, the water level detection sensor (2) monitoring the water level changes upstream and downstream in real time, and collecting the downstream surge data during the water discharge process, and the cloud control platform controlling the gate assembly to open the corresponding opening degree according to the transmitted surge data and the water level difference upstream and downstream of the gate mechanism (1) after the water discharge is completed, replenishing water with minimum water energy loss, compensating for the total water discharge reduction caused by the surge, and achieving sufficient drainage and irrigation water volume.

2. The open channel water management system for farmland irrigation area according to claim 1, characterized in that: The gate assembly comprises a main frame (10) and two gate plates (12). The two gate plates (12) are triangularly mounted on the lower end surface of the main frame (10). The two gate plates (12) are hinged to each other near the triangular ends. The rear end of each gate plate (12) is rotatably connected to a tail plate portion (13). The upper end of the tail plate portion (13) is slidably mounted on the lower end surface of the main frame (10). An opening and closing connecting piece is mounted on each tail plate portion (13). The opening and closing connecting piece is controlled to move toward the center direction of the main frame (10) by a controllable power source. The two gate plates (12) are close to each other. The opening distance between the tail plate portion (13) and the vertical plate portion on the main frame (10) is the opening degree of the gate. The upstream water flow passes through the two gate plates (12) to divert the water flow flowing into the downstream and guides the water to the openings on both sides for release.

3. The open channel water management system for farmland irrigation area according to claim 2, characterized in that: The flow blocking assembly comprises a float (26) and a plurality of water baffles (20); an inner concave cavity (19) is arranged on the front end surface of the gate plate (12); a notch (14) is arranged on the upper end surface of the gate plate (12) at the position of the inner concave cavity (19); a rotating shaft (15) is rotatably installed in the notch (14) and penetrates into the inner concave cavity (19); each of the water baffles (20) is fixedly installed on the rotating shaft (15); a gear (16) is fixedly connected to the rotating shaft (15); a slide groove cavity (18) is arranged in the notch (14) and communicates with the slide groove cavity (18) ), a rack (17) is slidably installed in the chute cavity (18), the rack (17) is meshed with the rotating shaft (15), one end of the rack (17) is connected to the inner wall of the chute cavity (18) by a compression spring, and the other end is fixedly connected to the float (26) by a wire rope (25), the float (26) is placed in the downstream water flow and is subjected to the impact force of the water flow, and pulls the rack (17) to drive the water baffle (20) to flip open, and the magnitude of the water flow impact force is proportional to the flip-open angle of the water baffle (20).

4. The open channel water management system for farmland irrigation area according to claim 3, characterized in that: The opening and closing connection member comprises a connection block (21) fixedly mounted on the tail plate portion (13), a connecting rod (23) being hinged on the connection block (21), a servo motor (11) being fixedly mounted on the upper end surface of the main frame (10), a lead screw (22) being fixedly connected to the output end of the servo motor (11), a threaded sleeve (24) being threadedly connected to the lead screw (22), the connecting rod (23) being hingedly connected to the threaded sleeve (24), and the cloud control platform issuing an opening command to control the number of rotations of the lead screw (22) to control the moving distance of the tail plate portion (13).

5. The open channel water management system for farmland irrigation area according to claim 4, characterized in that: The water baffle (20) is arranged in an arc shape, and the width of the water baffle (20) gradually increases from top to bottom.

6. The open channel water management system for farmland irrigation area according to claim 5, characterized in that: Water contact plates (27) are respectively installed on both sides of the floating member (26).

7. The open channel water management system for farmland irrigation area according to claim 1, characterized in that: The method for replenishing the water loss caused by surge specifically comprises the following steps: S1: Send a water release command to the cloud control platform based on the downstream water demand. The cloud control platform controls the gate to open and discharge the theoretical water volume within time T; S2: Using a water level detection sensor to detect the number and height of the surge waves generated downstream within a time T, the cloud control platform calculates the actual water release volume based on the collected surge data, the gate data when the water is released, and the initial water levels of the upstream and downstream, thereby obtaining the loss of water release volume △V caused by the surge; S3: After obtaining the lost water release volume, the gate opening is dynamically controlled to replenish water according to the upstream and downstream water level data before replenishment, and the gate opening is synchronously changed according to the upstream and downstream water level difference changes to complete water release and replenishment in the shortest time while minimizing the loss of water energy.

8. The open channel water management system for farmland irrigation area according to claim 7, characterized in that: The method for detecting the number and height of the swells generated downstream comprises the following steps: First, the static water level data at least ten minutes before the gate is opened to release water is extracted as a benchmark; Secondly, the minimum wave crest height threshold is set to control the sampling frequency and the number of surges is identified through wave crest detection; Finally, the difference between each wave crest and its adjacent wave trough is calculated to calculate the surge height, and the maximum surge height and the average surge height are recorded in time series.

9. The open channel water management system for farmland irrigation area according to claim 8, characterized in that: Specific method for obtaining the loss of water discharge △V The following steps are involved: Q1: Add a correction coefficient to the average surge height as the amplitude of the downstream water level fluctuation due to the surge, and use the water level data of the downstream water level and the amplitude of the fluctuation to obtain the instantaneous value of the downstream water level; Q2: The difference between the monitored upstream water level data and the instantaneous value of the downstream water level is used as the effective water head, and then the instantaneous flow is obtained by using the opened gate parameters and the effective water head; Q3: The instantaneous flow rate is numerically integrated within time T to obtain the actual water release volume. The difference between the theoretical water release volume and the actual water release volume is the loss water release volume △V.

10. The open channel water management system for farmland irrigation area according to claim 9, characterized in that: The dynamic control of the gate opening in step S3 specifically includes the following methods: The water replenishment flow rate per unit time is calculated using the lost water discharge volume △V and the water replenishment time set according to demand. It is only necessary to maintain the water replenishment flow rate unchanged, and adjust the gate opening according to the water level difference between upstream and downstream. When the water level difference between upstream and downstream gradually decreases, the gate opening is gradually expanded.

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