A regulation method and system for the subsurface flow position of stormwater runoff entering a stratified reservoir

Abstract

The present invention discloses a regulation method and system for the subsurface flow position of storm runoff entering a stratified reservoir, which relates to the field of reservoir flood season management. The method includes obtaining 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 upper and lower layers of water in the reservoir are mixed by turning on the forced mixing system arranged in the reservoir, and the water body stratification is destroyed to change the thermal stratification structure of the reservoir water body, so that the temperature difference between the bottom water temperature and the surface water temperature of the reservoir is within the preset range. The turbidity of the incoming reservoir runoff of the storm runoff is obtained in real time. When the turbidity of the incoming reservoir runoff is greater than or equal to the preset value, the forced mixing system is turned off to stop the mixing action of the upper and lower layers of water in the reservoir, and the incoming reservoir runoff enters the reservoir in the form of bottom subsurface flow, and the flood discharge outlet arranged at the bottom of the reservoir is opened to discharge the storm runoff from the reservoir.

Description

Technical Field

[0001] The present invention relates to the technical field of reservoir flood season management, and particularly relates to a method and system for regulating the subsurface flow position of storm runoff entering a stratified reservoir. Background Art

[0002] With the restriction of groundwater extraction and the implementation of long-distance water diversion projects, the role of reservoirs as drinking water sources has become increasingly prominent. However, their special hydrological and hydrodynamic conditions have caused water quality pollution problems such as external runoff pollution input, surface algae reproduction, and anaerobic release of sediment. Chinese Patent ZL201210090207.3 discloses a water quality improvement device for deep-water source reservoirs by pumping and aerating, which can mix and oxygenate the water body of deep-water source reservoirs, inhibit the release of sediment pollution and the growth of algae. Therefore, the internal pollution of stratified reservoirs has been effectively controlled.

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

[0004] Due to solar radiation and atmospheric heat transfer, the surface water temperature of deep-water reservoirs is high and the bottom water temperature is low in summer and autumn under natural conditions, being in a stable thermal stratification state. The water temperature of storm runoff generated by basin rainfall is lower than the surface water temperature of the reservoir and higher than the bottom water temperature, and the sediment content of most storm runoff is low (<1 kg / m³). According to the principle of density flow, storm runoff will enter the reservoir as subsurface flow in the middle under the combined action of water temperature and sediment, directly deteriorating the water quality of the water intake located in the middle of the reservoir. Moreover, the particulate pollutants carried by storm runoff will naturally settle in the main reservoir area, causing large-scale water quality pollution in the middle and lower parts of the reservoir and forming potential internal pollution sources by silt deposition at the bottom of the reservoir. Chinese Patent ZL202011609951.0 discloses a guiding device and method suitable for draining turbid water and storing clear water in a source reservoir, and the proposed movable flood discharge head can discharge high-turbidity water according to the subsurface flow position of storm runoff. However, 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 subsurface flow position of storm runoff entering a stratified reservoir to solve the above problems existing in the prior art, that is, how to quickly discharge storm runoff with a high pollution load in the prior art. The present invention provides a method for regulating the subsurface flow position of storm runoff entering a stratified reservoir, and the method includes:

[0006] Obtain the bottom water temperature and the surface water temperature of the reservoir;

[0007] When the water temperature at the surface of the reservoir exceeds the preset range of the water temperature at the bottom of the reservoir, by turning on the forced mixing system arranged in the reservoir, the upper and lower layers of water in the reservoir are mixed to break the water body stratification, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the water temperature at the bottom of the reservoir and the water temperature at the surface of the reservoir within the preset range;

[0008] Obtain the turbidity of the incoming reservoir runoff of the rainstorm runoff in real time. When the turbidity of the incoming reservoir runoff is greater than or equal to the preset value, turn off the forced mixing system to stop the mixing action of the upper and lower layers of water in the reservoir, make the incoming reservoir runoff enter the reservoir in the form of bottom underflow, and open the flood discharge outlet arranged at the bottom of the reservoir to discharge the rainstorm runoff from the reservoir.

[0009] Optionally, the elevation of the water intake of the reservoir is located in the upper middle part, or a water intake with stratified control is set in the reservoir to take water at different elevations.

[0010] Optionally, the forced mixing system specifically includes:

[0011] A water-lifting aeration system, a water-lifting cylinder system, a mechanical circulation mixing system, and an air pipe mixing system; among them, the water-lifting aeration system is installed at the bottom of the reservoir.

[0012] Optionally, when the turbidity of the incoming reservoir runoff is greater than or equal to 50 NTU, turn off the forced mixing system.

[0013] Optionally, the opening degree of the gate arranged on the flood discharge outlet is adjustable.

[0014] It also includes:

[0015] When the turbidity at the bottom of the reservoir is less than 20 NTU, restart the forced mixing system to mix the upper and lower layers of water in the reservoir and break the water body stratification.

[0016] The present invention provides a regulation system for the underflow position of rainstorm runoff entering a stratified reservoir, including:

[0017] An acquisition module for acquiring the water temperature at the bottom of the reservoir and the water temperature at the surface of the reservoir;

[0018] A regulation module for, when the water temperature at the surface of the reservoir exceeds the preset range of the water temperature at the bottom of the reservoir, by turning on the forced mixing system arranged in the reservoir, mixing the upper and lower layers of water in the reservoir to break the water body stratification, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the water temperature at the bottom of the reservoir and the water temperature at the surface of the reservoir within the preset range; obtaining the turbidity of the incoming reservoir runoff of the rainstorm runoff in real time. When the turbidity of the incoming reservoir runoff is greater than or equal to the preset value, turn off the forced mixing system to stop the mixing action of the upper and lower layers of water in the reservoir, make the incoming reservoir runoff enter the reservoir in the form of bottom underflow, and open the flood discharge outlet arranged at the bottom of the reservoir to discharge the rainstorm runoff from the reservoir.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a method for regulating the position of storm runoff entering the subsurface flow of a stratified reservoir. This method guides storm runoff to enter the reservoir in the form of bottom subsurface flow through a forced mixing system, precisely regulating the subsurface flow position of storm runoff. It not only ensures the safety of the reservoir water supply quality but also effectively reduces the sedimentation of storm runoff pollutants in the reservoir, thereby avoiding the pollution of the upper and middle water bodies in the reservoir caused by storm runoff and the problem of deterioration of the water supply quality. At the same time, when there is storm runoff, the opening of the bottom flood discharge outlet realizes the rapid discharge of storm runoff with a high pollution load, achieving the purpose of "discharging turbidity and storing clarity". BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments in accordance with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0021] Figure 1 It is a flowchart of a method for regulating the position of storm runoff entering the subsurface flow of a stratified reservoir provided by an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of water supply quality pollution caused by storm runoff entering a stratified water source reservoir in the form of middle-layer subsurface flow provided by an embodiment of the present invention;

[0023] Figure 3 It is a schematic diagram of the forced mixing system inducing bottom subsurface flow to reduce storm runoff pollution provided by an embodiment of the present invention;

[0024] Among them, Figure 3 (a) of is a schematic diagram of complete mixing achieved by continuous operation of the forced mixing system before storm runoff enters the reservoir, Figure 3 and (b) of is a schematic diagram of the forced mixing system stopping operation;

[0025] Figure 4 It is the vertical water temperature and turbidity distribution after storm runoff enters a certain stratified water source reservoir in different forms provided by an embodiment of the present invention;

[0026] Among them, Figure 4 (a) of is a schematic diagram of middle-layer subsurface flow in the natural stratification state, Figure 4 and (b) of is a schematic diagram of forced mixing inducing bottom subsurface flow. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The technical solutions of the present invention and how the technical solutions of the present invention solve the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below 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 with reference to the accompanying drawings.

[0029] Embodiment 1

[0030] Figure 1 is a flowchart of a method for regulating the subsurface flow position of storm runoff entering a stratified reservoir provided by an embodiment of the present invention. As Figure 1 shown, a method for regulating the subsurface flow position of storm runoff entering a stratified reservoir shown in this embodiment includes:

[0031] S1: Obtain the water temperature at the bottom layer of the reservoir and the water temperature at the surface layer of the reservoir.

[0032] Exemplarily, before the flood season arrives, vertical water temperature monitoring of the reservoir can be continuously carried out, including obtaining the water temperature at the bottom layer of the reservoir and the water temperature at the surface layer of the reservoir.

[0033] S2: When the water temperature at the surface layer of the reservoir exceeds the preset range of the water temperature at the bottom layer of the reservoir, turn on the forced mixing system arranged in the reservoir to mix the upper and lower layers of water in the reservoir and destroy the water body stratification, so as to change the thermal stratification structure of the reservoir water body and make the temperature difference between the water temperature at the bottom layer of the reservoir and the water temperature at the surface layer of the reservoir within the preset range.

[0034] Exemplarily, 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 water body thermal stratification, increase the bottom water body temperature, and make the bottom water temperature tend to be consistent with the surface water temperature (for example, the temperature difference ≤ 1 °C).

[0035] Exemplarily, a forced mixing system may include, for example, a pumping aeration system, a pumping cylinder system, a mechanical circulation mixing system, and an air pipe mixing system. The pumping aeration system includes a multi-functional pumping aerator, a compressed air preparation system, and an air supply pipeline. The pumping aerator mainly includes a microporous aerator, an aeration chamber, a reflux chamber, an air chamber, a rising cylinder, a watertight bin, 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 through the air supply pipeline in a continuous flow manner, 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 accumulates in the air chamber, and an inverted U-shaped water seal device is provided in the air chamber. When the air accumulates to the lower edge of the water seal chamber and breaks the water seal, it is instantaneously released into the rising cylinder to form an air slug, which accelerates upward along the rising cylinder, forming 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 downward, forming a water body movement from top to bottom outside the device, so as to achieve the purpose of mixing the upper and lower water layers and destroying the water body stratification.

[0036] The pumping cylinder system includes a pumping cylinder, a compressed air preparation system, and an air supply pipeline; among them, the pumping 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 the pumping aerator. That is, the air in the air chamber accumulates and is instantaneously released into the rising cylinder to form an air slug and accelerates upward, driving the bottom water body to rise, so as to form a water body movement from bottom to top inside the device and from top to bottom outside the device, realizing the mixing of the upper and lower water layers. Compared with the pumping aeration system, the pumping cylinder system does not have the function of directly oxygenating the bottom water body.

[0037] The mechanical circulation mixing system includes an axial flow impeller, a motor, and a draft tube. The motor drives the axial flow impeller to move to drain the bottom water body of the reservoir along the draft tube to the surface layer or drain the surface water body to the bottom layer, so as to form a circulating flow of the upper and lower water bodies, achieving the purpose of destroying the water body stratification.

[0038] The air pipe mixing system includes an air compressor, an air release device, and an air supply pipeline. The air release device is installed at the bottom of the reservoir. The compressed air generated by the air compressor is transported to the air release device through the air supply pipeline and continuously released in the form of small bubbles. When the bubbles rise, they entrain the denser water body in the lower layer to the surface layer. After the bubbles escape into the atmosphere, the high-density water body diffuses around, and after mixing with the lower-density water body in the surface layer, it sinks outside the rising bubble plume, gradually realizing the mixing of the upper and lower water bodies.

[0039] As Figure 2 shown, when the storm runoff enters the reservoir, it will enter the stratified water source reservoir in the form of middle-layer subsurface flow, which will cause water quality pollution of the water supply; as Figure 3 shown in (a) of

[0040] S3: Obtain the turbidity of the incoming reservoir runoff of the rainstorm runoff in real time. When the turbidity of the incoming reservoir runoff is greater than or equal to the preset value, turn off the forced mixing system to stop the mixing action of the upper and lower layers of water in the reservoir, allow the incoming reservoir runoff to enter the reservoir in the form of bottom underflow, and open the flood discharge outlet set at the bottom of the reservoir to discharge the rainstorm runoff from the reservoir.

[0041] Exemplarily, as the rainfall in the basin and the flow rate of the incoming reservoir runoff increase, the turbidity and sediment content of the incoming reservoir runoff correspondingly increase. When the turbidity of the incoming reservoir runoff ≥ 50 NTU, the forced mixing system can be turned off. Under the action of density flow, the incoming reservoir runoff with lower water temperature, higher sediment content, and larger water body density enters the reservoir in the form of bottom underflow, as shown in (b) of Figure 3 ; Water is supplied by the water intake located in the upper-middle part of the reservoir where the water quality is not affected by the rainstorm runoff to ensure high-quality water supply; at the same time, open the bottom flood discharge outlet to discharge the rainstorm runoff with a higher pollution load from the reservoir, reducing the deposition of particulate pollutants in the reservoir.

[0042] Exemplarily, for example, after the peak runoff of the flood is over, continuous vertical turbidity monitoring of the reservoir area can be carried out. When the turbidity at the bottom of the reservoir drops to < 20 NTU, the forced mixing system is restarted to keep the reservoir in a fully mixed state to cope with the next rainstorm runoff.

[0043] Optionally, water is taken through a water intake set in the upper-middle part of the reservoir.

[0044] Exemplarily, the water intake can be a fixed water intake located in the upper-middle part of the reservoir, or an adjustable water intake device that can selectively take water at different elevations. The flood discharge outlet can be set at the bottom of the reservoir and the opening degree of the flood discharge outlet gate can be adjusted. The rainstorm runoff with a high pollution load is discharged from the reservoir through the flood discharge outlet to avoid long-term and large-scale water quality pollution in the middle and lower parts of the water body caused by the settlement of particulate pollutants in the reservoir area and the accumulation of pollutants at the bottom of the reservoir.

[0045] Embodiment 2

[0046] To further clarify the objectives and technical solutions of the present application, next, a certain stratified water source reservoir in a certain place is taken as an example to illustrate the technical solutions of this invention.

[0047] The maximum storage capacity of a certain stratified water source reservoir in a certain place is 52.6 million m 3 , the maximum water depth is 80 m, and the base flow rate of the incoming reservoir during the non-rainy season in summer is 0.7 - 0.8 m 3 / s.

[0048] In 2017, the pumping aeration forced mixing system was not installed in this reservoir, and the reservoir was in a stable thermal stratification state in summer and autumn. On September 28, the water temperatures of the surface layer and the bottom layer were 20.3 and 6.7 °C respectively; the flow rate of the incoming rainstorm runoff was 26.1 m 3 / s, the water temperature is 14.2 °C, and the density of the incoming runoff water body is between the densities of the surface water body and the bottom water body of the reservoir. Therefore, the runoff enters the reservoir in the form of middle-layer subsurface flow, resulting in a significant increase in turbidity in the range of elevation 820 - 850 m near the water intake (the elevation of the water intake is 840 m), reaching a maximum of 254 NTU, as shown in Figure 4 (a) of

[0049] From September 1st to 19th, 2023, the pumping and aeration forced mixing system of this reservoir was continuously operated, achieving complete mixing. On September 29th, the surface and bottom water temperatures were 20.2 and 18.6 °C respectively; the flow rate of the incoming rainstorm runoff on that day was 127 m 3 / s, the water temperature is 12.0 °C, and the density of the incoming runoff water body is significantly higher than the density of the bottom water body of the reservoir. Therefore, the runoff enters the reservoir in the form of bottom-layer subsurface flow, and there is only a significant increase in turbidity and pollutant concentration in the range below elevation 830 m, and the water body above elevation 830 m is basically not affected, as shown in Figure 4 (b) of. Comparing with the subsurface flow situation and water quality impact of the same period in 2017, it is proved that forcing the subsurface flow of rainstorm runoff through forced mixing can effectively reduce the pollution of the water quality of the water supply at the water intake by rainstorm runoff.

[0050] The present invention provides a method for regulating the subsurface flow position of rainstorm runoff entering a stratified reservoir. Before rainfall, the operation of the forced mixing system is used to destroy the water body stratification structure, significantly increase the temperature of the bottom water body, reduce the density of the bottom water body, and induce the formation of bottom-layer subsurface flow of rainstorm runoff, so as to avoid the pollution of the middle and upper water bodies in the reservoir and ensure the water supply quality.

[0051] Embodiment 3

[0052] The above is the method for regulating the subsurface flow position of rainstorm runoff entering a stratified reservoir provided by one or more embodiments of this specification. Based on the same idea, this specification also provides a corresponding system for regulating the subsurface flow position of rainstorm runoff entering a stratified reservoir, including:

[0053] An acquisition module for acquiring the bottom water temperature and the surface water temperature of the reservoir;

[0054] A regulation module for, when the surface water temperature of the reservoir exceeds the preset range of the bottom water temperature, mixing the upper and lower layers of water in the reservoir and destroying the water body stratification by turning on the forced mixing system disposed in the reservoir to change the thermal stratification structure of the reservoir water body so that the temperature difference between the bottom water temperature and the surface water temperature of the reservoir is within the preset range; acquiring the incoming runoff turbidity of the rainstorm runoff in real time, and when the incoming runoff turbidity is greater than or equal to the preset value, turning off the forced mixing system to stop the mixing action of the upper and lower layers of water in the reservoir, allowing the incoming runoff to enter the reservoir in the form of bottom-layer subsurface flow, and opening the flood discharge outlet provided at the bottom of the reservoir to discharge the rainstorm runoff from the reservoir.

[0055] For the specific limitations of the control system for the subsurface flow position of storm runoff entering a stratified reservoir, reference can be made to the limitations of the control method for the subsurface flow position of storm runoff entering a stratified reservoir in the foregoing text, which will not be elaborated herein. Each module in the above control system for the subsurface flow position of storm runoff entering a stratified reservoir can be implemented in whole or in part through software, hardware, and their combinations. The above-mentioned modules can be embedded in or independent of the processor in a computer device in the form of hardware, or stored in the memory of the computer device in the form of software, so as to facilitate the processor to call and execute the operations corresponding to each of the above modules.

[0056] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope recorded in 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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