Method and system for regulating and controlling undercurrent position of rainstorm runoff entering stratified reservoir

Abstract

The invention discloses a method and a system for regulating and controlling the underflow position of rainstorm runoff entering a stratified reservoir, and relates to the field of reservoir flood season management. When the water temperature of the surface layer of the reservoir exceeds the preset range of the water temperature of the bottom layer of the reservoir, starting a forced mixing system arranged in the reservoir, mixing upper and lower layers of water in the reservoir and breaking water layering so as to change the thermal layering structure of the water in the reservoir and enable the temperature difference between the water temperature of the bottom layer of the reservoir and the water temperature of the surface layer of the reservoir to be within the preset range; the reservoir runoff turbidity of the rainstorm runoff is obtained in real time, when the reservoir runoff turbidity is larger than or equal to a preset value, the forced mixing system is closed so as to stop the action of mixing upper-layer water and lower-layer water in the reservoir, the reservoir runoff enters the reservoir in a bottom-layer underflow mode, and a flood discharge opening formed in the bottom of the reservoir is opened so that the rainstorm runoff can be discharged out of the reservoir.

Description

Technical Field

[0001] The invention relates to the technical field of reservoir flood season management, and in particular to a method and system for regulating the entry of storm runoff into the undercurrent position of a stratified reservoir. Background Art

[0002] With the restriction of groundwater exploitation and the implementation of long-distance water diversion projects, the role of reservoirs as drinking water sources has become increasingly prominent, but their special hydrological and hydrodynamic conditions have caused water pollution problems such as external runoff pollution input, surface algae reproduction, and anaerobic release of bottom mud. Chinese patent ZL201210090207.3 discloses a deep-water source reservoir pumping aeration water quality improvement device, which can mix and oxygenate the water body of the deep-water source reservoir, inhibit the release of bottom mud pollution and algae growth, so that the endogenous pollution of the stratified reservoir can be effectively controlled.

[0003] In terms of external pollution of reservoirs, although point source pollution such as domestic and industrial pollution has been effectively controlled, non-point source pollution cannot be avoided. Even in river basins dominated by natural forests and grasslands, rainstorm runoff will carry a large amount of natural organic matter, nutrients, minerals, etc. into the reservoir. The greater the runoff volume, the higher the sand content and pollution load of the rainstorm runoff.

[0004] Due to solar radiation and atmospheric heat transfer, the surface water temperature of deep-water reservoirs in summer and autumn is high and the bottom water temperature is low under natural conditions, and they are in a stable thermal stratification state. The water temperature of the storm runoff generated by rainfall in the basin is lower than the surface water temperature of the reservoir but higher than the bottom water temperature, and most of the storm runoff has a low sand content (<1kg / m3). According to the density flow principle, the storm runoff will enter the reservoir as a middle undercurrent under the combined action of water temperature and sediment, directly causing the water quality of the water intake located in the middle of the reservoir to deteriorate, and the particulate pollutants carried by the storm runoff will naturally settle in the main reservoir area, causing large-scale water pollution in the middle and lower water bodies of the reservoir, and silting up at the bottom of the reservoir to form a potential endogenous pollution source. Chinese Patent ZL202011609951.0 discloses a guiding device and method suitable for draining turbid water and storing clear water in water source reservoirs. The proposed movable flood discharge head can discharge highly turbid water according to the position of the storm runoff undercurrent, but due to its complex structure, it is difficult to quickly discharge the storm runoff entering the reservoir. Summary of the invention

[0005] The present invention provides a method and system for regulating the entry of storm runoff into the subsurface flow position of a stratified reservoir, which is used to solve the above-mentioned problem existing in the prior art, that is, how to achieve the rapid discharge of storm runoff with high pollution load in the prior art. The present invention provides a method for regulating the entry of storm runoff into the subsurface flow position of a stratified reservoir, and the method comprises: Obtain the bottom water temperature and the surface water temperature of the reservoir; When the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature of the reservoir, the forced mixing system arranged in the reservoir is turned on to mix the upper and lower water layers in the reservoir and destroy the water stratification, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the bottom water temperature of the reservoir and the surface water temperature of the reservoir within the preset range; The turbidity of the inflow runoff of the storm runoff is obtained in real time. When the turbidity of the inflow runoff is greater than or equal to the preset value, the forced mixing system is closed to stop the mixing of the upper and lower layers of water in the reservoir, and the inflow runoff enters the reservoir in the form of bottom undercurrent, and the flood discharge port set at the bottom of the reservoir is opened to discharge the storm runoff from the reservoir.

[0006] Optionally, the water intake elevation of the reservoir is located in the upper middle part, or a stratified controlled water intake is set in the reservoir to draw water at different elevations.

[0007] Optionally, the forced mixing system specifically includes: Water lifting and aeration system, water lifting cylinder system, mechanical circulation mixing system, air pipe mixing system; wherein the water lifting and aeration system is installed at the bottom of the reservoir.

[0008] Optionally, when the turbidity of the inflow runoff is greater than or equal to 50 NTU, the forced mixing system is turned off.

[0009] Optionally, the gate opening provided on the flood discharge outlet is adjustable.

[0010] Also includes: When the turbidity at the bottom of the reservoir is less than 20 NTU, the forced mixing system is reopened to mix the upper and lower layers of water in the reservoir and destroy the water stratification.

[0011] The present invention provides a control system for storm runoff entering the undercurrent position of a stratified reservoir, comprising: An acquisition module is used to obtain the bottom water temperature and the surface water temperature of the reservoir; The control module is used to start the forced mixing system arranged in the reservoir to mix the upper and lower water layers in the reservoir and destroy the water stratification when the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature of the reservoir, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the bottom water temperature of the reservoir and the surface water temperature of the reservoir within a preset range; obtain the turbidity of the inflow runoff of the storm runoff in real time, and when the turbidity of the inflow runoff is greater than or equal to the preset value, close the forced mixing system to stop the mixing of the upper and lower water layers in the reservoir, let the inflow runoff enter the reservoir in the form of bottom undercurrent, and open the flood discharge port arranged at the bottom of the reservoir to discharge the storm runoff out of the reservoir.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a method for regulating the undercurrent position of storm runoff entering a stratified reservoir, which guides the storm runoff into the reservoir in the form of bottom undercurrent through a forced mixing system, and accurately regulates the undercurrent position of the storm runoff, which not only ensures the safety of the water quality of the reservoir water supply, but also effectively reduces the siltation of storm runoff pollutants in the reservoir, thereby avoiding the pollution of the upper and middle water bodies of the reservoir by storm runoff, causing the deterioration of the water quality of the water supply; at the same time, when the storm runoff passes, the bottom flood discharge port is opened, which realizes the rapid discharge of storm runoff with high pollution load, and achieves the purpose of "draining turbid water and storing clear water". BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0014] Figure 1 A flow chart of a method for regulating the entry of storm runoff into the undercurrent position of a stratified reservoir provided by an embodiment of the present invention; Figure 2 A schematic diagram of a rainstorm runoff according to an embodiment of the present invention entering a stratified water source reservoir as a mid-layer undercurrent causing water pollution; Figure 3 A schematic diagram of a forced mixing system provided in an embodiment of the present invention that induces bottom undercurrent to reduce rainstorm runoff pollution; in, Figure 3 (a) is a schematic diagram of the forced mixing system before the storm runoff enters the reservoir to achieve complete mixing. Figure 3 (b) is a schematic diagram of the forced mixing system stopping operation; Figure 4 The vertical water temperature and turbidity distribution of storm runoff from a stratified water source reservoir after entering the reservoir in different forms provided by an embodiment of the present invention; in, Figure 4 (a) is a schematic diagram of the middle-layer undercurrent under natural stratification. Figure 4 (b) is a schematic diagram of forced mixing induced bottom undercurrent. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] The technical solution of the present invention and how the technical solution of the present invention solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0017] Example 1 Figure 1 is a flow chart of a method for regulating the undercurrent position of a storm runoff entering a stratified reservoir provided by an embodiment of the present invention, such as Figure 1 As shown, this embodiment shows a method for regulating the rainstorm runoff entering the undercurrent position of the stratified reservoir, comprising: S1: Obtain the bottom water temperature and the surface water temperature of the reservoir.

[0018] For example, before the flood season arrives, vertical water temperature monitoring of the reservoir can be continuously carried out, including obtaining the bottom water temperature of the reservoir and the surface water temperature of the reservoir.

[0019] S2: When the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature of the reservoir, the forced mixing system installed in the reservoir is turned on to mix the upper and lower water layers in the reservoir and destroy the water stratification, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the bottom water temperature of the reservoir and the surface water temperature of the reservoir within the preset range.

[0020] For example, the forced mixing system can be started when the surface water temperature exceeds the bottom water temperature by more than 2°C, and the forced mixing system arranged in the reservoir can be continuously operated to destroy the thermal stratification of the water body, increase the bottom water temperature, and make the bottom water temperature tend to be consistent with the surface water temperature (for example, the temperature difference is ≤1°C).

[0021] Exemplary forced mixing systems may include, for example, a water-lifting aeration system, a water-lifting cylinder system, a mechanical circulation mixing system, and an air pipe mixing system. The water-lifting aeration system includes a multifunctional water-lifting aerator, a compressed air preparation system, and an air supply pipeline. The water-lifting aerator mainly includes a microporous aerator, an aeration chamber, a reflux chamber, an air chamber, a riser, a watertight chamber, an anchor pier, etc., and is vertically installed at the bottom of the reservoir. The compressed air prepared by the air compressor is transported to the microporous aerator in a continuous flow through the air supply pipeline, and is released to the aeration chamber through the microporous aerator, and the bottom water body is efficiently oxygenated in the aeration chamber; the compressed air overflowing from the aeration chamber is accumulated in the air chamber, and an inverted U-shaped water seal device is provided in the air chamber. After the air accumulates at the lower edge of the water seal chamber and destroys the water seal, it is instantly released into the riser to form an air bomb, which accelerates and rises along the riser to form a piston flow, driving the lower low-temperature water body to move upward. After the lifted bottom water is mixed with the surface water, the water temperature decreases, the density increases, and it migrates to the lower layer, forming a top-down water body movement outside the equipment, thereby achieving the purpose of mixing the upper and lower water layers and destroying the water body stratification.

[0022] The water-lifting cylinder system includes a water-lifting cylinder, a compressed air preparation system, and an air supply pipeline; the water-lifting cylinder includes a straight cylinder, an air chamber, a float, and an anchor pier, and is vertically installed at the bottom of the reservoir. Its air chamber structure is similar to that of a water-lifting aerator, and the air in the air chamber is accumulated and then instantly released into the rising cylinder to form an air bomb and accelerate the rise, driving the bottom water body to rise, thereby forming a water body movement from bottom to top inside the equipment and from top to bottom outside the equipment, achieving mixing of the upper and lower water layers. Compared with the water-lifting aeration system, the water-lifting cylinder system does not have the function of directly oxygenating the bottom water body.

[0023] The mechanical circulation mixing system includes an axial flow impeller, a motor, and a guide tube. The motor drives the axial flow impeller to move and divert the bottom water of the reservoir to the surface along the guide tube, or diverts the surface water to the bottom, thereby forming a circulating flow of the upper and lower water bodies, achieving the purpose of destroying the water stratification.

[0024] The air pipe mixing system includes an air compressor, an air releaser, and an air supply pipeline. The air releaser is installed at the bottom of the reservoir. The compressed air generated by the air compressor is transported to the air releaser through the air supply pipeline and released continuously in the form of small bubbles. When the bubbles rise, they carry the water with higher density in the lower layer to the surface. After the bubbles escape into the atmosphere, the high-density water diffuses to the surroundings, mixes with the water with lower density on the surface, and sinks outside the rising bubble plume, gradually achieving mixing of the upper and lower water bodies.

[0025] like Figure 2 As shown in Figure 1, when storm runoff enters the reservoir, it will enter the stratified water source reservoir as a mid-layer undercurrent, thus causing water pollution; Figure 3 As shown in (a), before the storm runoff enters the reservoir, the base flow water and the original reservoir water are completely mixed through the operation of the forced mixing system.

[0026] S3: The turbidity of the inflow runoff of the storm runoff is obtained in real time. When the turbidity of the inflow runoff is greater than or equal to the preset value, the forced mixing system is closed to stop the mixing of the upper and lower layers of water in the reservoir, and the inflow runoff enters the reservoir in the form of bottom undercurrent, and the flood discharge port set at the bottom of the reservoir is opened to discharge the storm runoff from the reservoir.

[0027] For example, as the rainfall in the basin and the flow rate of inflow increases, the turbidity and sediment content of the inflow increase accordingly. When the turbidity of the inflow is ≥50 NTU, the forced mixing system can be turned off, and the inflow with low water temperature, high sediment content and high water density enters the reservoir in the form of bottom undercurrent under the action of density flow, such as Figure 3 As shown in (b); use a water intake located in the upper and middle part of the reservoir where the water quality is not affected by storm runoff to ensure high-quality water supply; at the same time, open the bottom flood discharge port to discharge storm runoff with a higher pollution load out of the reservoir, reducing the accumulation of particulate pollutants in the reservoir.

[0028] For example, after the peak runoff ends, vertical turbidity monitoring of the reservoir area can be continuously carried out. When the turbidity at the bottom of the reservoir drops to <20 NTU, the forced mixing system can be restarted to keep the reservoir in a completely mixed state to prepare for the next rainstorm runoff.

[0029] Optionally, water is taken in by setting a water intake in the upper middle part of the reservoir.

[0030] Exemplarily, the water intake may be a fixed water intake located in the middle and upper part of the reservoir, or an adjustable water intake device that can selectively draw water at different elevations. The flood discharge outlet may be set at the bottom of the reservoir and the flood discharge outlet gate opening may be adjustable. Storm runoff with a high pollution load may be discharged from the reservoir through the flood discharge outlet, thereby avoiding long-term, large-scale water quality pollution in the middle and lower water bodies caused by the sedimentation of particulate pollutants in the reservoir area and the accumulation of pollutants at the bottom of the reservoir.

[0031] Example 2 In order to further clarify the objectives and technical solutions of the present application, the technical solution of this invention is explained below by taking a stratified water source reservoir in a certain place as an example.

[0032] The maximum storage capacity of a stratified water source reservoir in a certain place is 52.6 million m 3 The maximum water depth is 80m, and the base flow into the reservoir during the non-rainy period in summer is 0.7-0.8 m 3 / s.

[0033] In 2017, the reservoir was not equipped with a pumping aeration forced mixing system, and the reservoir was in a stable thermal stratification state in summer and autumn. On September 28, the surface and bottom water temperatures were 20.3 and 6.7℃ respectively; the storm runoff flow into the reservoir was 26.1m 3 / s, the water temperature is 14.2℃, and the density of the water body of the runoff entering the reservoir is between the density of the surface water body and the bottom water body of the reservoir. Therefore, the runoff enters the reservoir in the form of mid-layer undercurrent, causing a significant increase in turbidity in the range of 820-850m near the water intake (the water intake elevation is 840m), with the highest reaching 254NTU. Figure 4 As shown in (a).

[0034] From September 1 to 19, 2023, the reservoir's pumping aeration forced mixing system operated continuously, achieving complete mixing. On September 29, the surface and bottom water temperatures were 20.2 and 18.6°C respectively; the storm runoff flow into the reservoir on that day was 127m 3 / s, the water temperature is 12.0℃, and the density of the water body of the runoff entering the reservoir is significantly higher than that of the bottom water body of the reservoir. Therefore, the runoff enters the reservoir in the form of bottom undercurrent. Only in the area below 830m in elevation, the turbidity and pollutant concentrations increase significantly. The water bodies above 830m in elevation are basically unaffected. Figure 4(b) shows that the comparison with the runoff infiltration and water quality impact in the same period of 2017 proves that forced mixing to induce bottom undercurrent of storm runoff can effectively reduce the pollution of storm runoff to the water quality of water intake.

[0035] The present invention provides a method for regulating the position of undercurrent of storm runoff entering a stratified reservoir. Before rainfall, the stratified structure of the water body is destroyed, the temperature of the bottom water body is greatly increased, and the density of the bottom water body is reduced through the operation of a forced mixing system, so as to induce the storm runoff to form a bottom undercurrent, thereby avoiding the pollution of the upper water body in the reservoir by the storm runoff and ensuring the water quality of the water supply.

[0036] Example 3 The above is a method for regulating the storm runoff entering the undercurrent position of a stratified reservoir provided by one or more embodiments of this specification. Based on the same idea, this specification also provides a corresponding regulation system for storm runoff entering the undercurrent position of a stratified reservoir, including: An acquisition module is used to obtain the bottom water temperature and the surface water temperature of the reservoir; The control module is used to start the forced mixing system arranged in the reservoir to mix the upper and lower water layers in the reservoir and destroy the water stratification when the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature of the reservoir, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the bottom water temperature of the reservoir and the surface water temperature of the reservoir within a preset range; obtain the turbidity of the inflow runoff of the storm runoff in real time, and when the turbidity of the inflow runoff is greater than or equal to the preset value, close the forced mixing system to stop the mixing of the upper and lower water layers in the reservoir, let the inflow runoff enter the reservoir in the form of bottom undercurrent, and open the flood discharge port arranged at the bottom of the reservoir to discharge the storm runoff out of the reservoir.

[0037] Regarding the specific definition of the control system for storm runoff entering the undercurrent position of the stratified reservoir, please refer to the definition of the control method for storm runoff entering the undercurrent position of the stratified reservoir above, which will not be repeated here. Each module in the above-mentioned control system for storm runoff entering the undercurrent position of the stratified reservoir can be implemented in whole or in part through software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0038] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A method for regulating the undercurrent position of rainstorm runoff entering a stratified reservoir, characterized in that: include: Obtain the bottom water temperature and the surface water temperature of the reservoir; When the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature of the reservoir, the forced mixing system arranged in the reservoir is turned on to mix the upper and lower water layers in the reservoir and destroy the water stratification, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the bottom water temperature of the reservoir and the surface water temperature of the reservoir within the preset range; The turbidity of the inflow runoff of the storm runoff is obtained in real time. When the turbidity of the inflow runoff is greater than or equal to the preset value, the forced mixing system is closed to stop the mixing of the upper and lower layers of water in the reservoir, and the inflow runoff enters the reservoir in the form of bottom undercurrent, and the flood discharge port set at the bottom of the reservoir is opened to discharge the storm runoff from the reservoir.

2. The method for regulating the rainstorm runoff entering the undercurrent position of the stratified reservoir as claimed in claim 1, characterized in that: The water intake elevation of the reservoir is located in the middle and upper part, or a layered controlled water intake is set in the reservoir to take water at different elevations.

3. The method for regulating the rainstorm runoff entering the undercurrent position of the stratified reservoir as claimed in claim 1, characterized in that: The forced mixing system specifically comprises: Water lifting and aeration system, water lifting cylinder system, mechanical circulation mixing system, air pipe mixing system; wherein the water lifting and aeration system is installed at the bottom of the reservoir.

4. The method for regulating the rainstorm runoff entering the undercurrent position of the stratified reservoir as claimed in claim 1, characterized in that: When the turbidity of the inflow runoff is greater than or equal to 50 NTU, the forced mixing system is turned off.

5. The method for regulating the rainstorm runoff entering the undercurrent position of the stratified reservoir as claimed in claim 1, characterized in that: The gate opening arranged on the flood discharge outlet is adjustable.

6. The method for regulating the storm runoff entering the undercurrent position of the stratified reservoir as claimed in claim 1, characterized in that: Also includes: When the turbidity at the bottom of the reservoir is less than 20 NTU, the forced mixing system is reopened to mix the upper and lower layers of water in the reservoir and destroy the water stratification.

7. A control system for storm runoff entering the undercurrent position of a stratified reservoir, characterized in that: include: An acquisition module is used to obtain the bottom water temperature and the surface water temperature of the reservoir; The water layer mixing module is used to start the forced mixing system arranged in the reservoir to mix the upper and lower layers of water in the reservoir and destroy the water stratification when the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature of the reservoir, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the bottom water temperature of the reservoir and the surface water temperature of the reservoir within the preset range; The control module is used to obtain the turbidity of the incoming runoff of the storm runoff in real time. When the turbidity of the incoming runoff is greater than or equal to the preset value, the forced mixing system is closed to stop the mixing of the upper and lower layers of water in the reservoir, and the incoming runoff enters the reservoir in the form of bottom undercurrent, and the flood discharge port set at the bottom of the reservoir is opened to discharge the storm runoff from the reservoir.

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