Ecological restoration reconstruction method of diversion type power station system

Abstract

This invention provides an ecological restoration and renovation method for a diversion-type hydropower station system, comprising the following steps: designing a water supply pipe between the upstream of the dam and the dewatering section of the river, with the water supply pipe and the water diversion tunnel respectively located on the left and right sides of the river channel; collecting information on the flood season, freezing period, and aquatic organism types of the dewatering section within a year, and initially determining the ecological base flow of the water supply pipe; collecting the normal water level elevation and dead water level elevation of the dam, and calculating the inlet elevation, effective head, inlet velocity, and pipe diameter of the water supply pipe; initially determining the length of the water supply pipe, the relative slope between the axial direction of the water supply pipe and the horizontal plane, and calculating the water level difference between the inlet and outlet. Using the technical solution of this invention, the water supply pipe and the power station operate independently, ensuring a continuous and stable ecological discharge flow, maintaining the ecological balance of the dewatering section, avoiding damage to the dam and riverbanks, simplifying construction, and eliminating safety hazards.

Description

Technical Field

[0001] This invention relates to the field of water conservancy facilities technology, and in particular to an ecological restoration and transformation method for a water diversion power station system. Background Technology

[0002] A diversion-type hydroelectric power station is a type of hydroelectric power station that uses artificially constructed water diversion channels, tunnels, or pipelines to divert river water downstream to create a concentrated drop in elevation for power generation. Its core features include the use of low dam or damless water intake. The existing water diversion power station system includes a power station, a water diversion tunnel (1) and a dam (2) set in the river channel. One end of the water diversion tunnel (1) is connected to the upstream of the dam (2), and the other end of the water diversion tunnel (1) is connected to the tailwater outlet downstream of the dam (2). The power station is set in the middle of the water diversion tunnel (1). Water diversion power stations are suitable for mountain river sections with large drops, and the highest head can reach more than 2,000 meters. However, for water diversion power stations without ecological flow discharge facilities, when they are in operation, because some water upstream of the dam (2) flows out through the water diversion tunnel (1), the river channel between the dam (2) and the tailwater outlet is in a water-deficient section for a long time, and even dehydration and flow interruption occur. This seriously affects the ecological environment of the river channel downstream of the dam (2), causing abnormal water temperature in the river channel downstream of the dam (2), poor vegetation growth due to lack of water, and blocking the migration channel of aquatic organisms such as fish downstream of the dam (2).

[0003] In the prior art, patent document with publication number "CN120174794A" discloses an ecological flow release system and method for a hydropower station. The ecological flow release system includes a bypass pipe, the inlet end of which is connected to a pressure steel pipe, and the bypass pipe is used to divert water flow within the pressure steel pipe; a measuring weir, which is connected to the outlet end of the bypass pipe, and the measuring weir is used for ecological flow release; a monitoring module, which is installed on the measuring weir, and the monitoring module is used to monitor the water level data of the measuring weir; and a control valve, which is installed on the bypass pipe, and the control valve is used to adjust the water flow rate of the bypass pipe according to the analysis results of the water level data, so as to control the flow release amount of the measuring weir. The patented technology solution realizes the ecological flow release of the pressure steel pipe water diversion hydropower station and improves the stability and ecological benefits of the ecological flow release. However, the ecological flow release structure of the patented technology relies too much on the water diversion steel pipe. Only when the power station is running can part of the water source be diverted to the bypass pipe to realize the ecological flow release and complete the irrigation and water supply of the dewatered section (3). This results in poor sustainability and stability of the ecological flow release. In addition, most of the early water diversion hydropower stations built in China did not have ecological flow release devices. For these early water diversion hydropower stations, it is difficult to add ecological flow release devices. If holes or openings are drilled on the surface of the existing dam (2), it is very easy to cause local stress concentration on the surface of the dam (2), which will affect the stability of the dam (2) and pose a great safety risk. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an ecological restoration and transformation method for a diversion-type power station system.

[0005] The present invention is achieved through the following technical solutions.

[0006] This invention provides an ecological restoration and renovation method for a diversion-type hydropower station system, comprising the following steps: Step 1: Provide a water diversion power station system, which includes a power station, a water diversion tunnel, and a dam set in the river channel. One end of the water diversion tunnel is connected to the upstream of the dam, and the other end of the water diversion tunnel is connected to the tailrace downstream of the dam. The power station is set in the middle of the water diversion tunnel. The river channel between the dam and the tailrace is designated as a dewatering section. A water supply pipe is designed between the upstream of the dam and the dewatering section. The water supply pipe and the water diversion tunnel are respectively set on the left and right sides of the river channel, and one end of the water supply pipe is designated as the inlet and the other end as the outlet. Step Two: Collect information on the flood season, freezing period, and aquatic organism types of the dewatering river section mentioned in Step One within one year, and preliminarily estimate the ecological base flow rate of the water replenishment pipe based on the above information. ; Step 3: Collect and obtain the normal water level elevation of the dam mentioned in Step 1. and dead water level elevation The elevation of the water inlet of the water supply pipe is calculated sequentially according to the following formulas. Functional head Inlet flow rate And pipe diameter D: ; in, ; = - ; ; in: It is the flow velocity coefficient, and ; ; Step 4: Initially determine the length L of the water supply pipe, the relative slope i between the axial direction of the water supply pipe and the horizontal plane, and calculate the water level difference ∆H between the inlet and outlet according to the following formula: .

[0007] The ecological restoration and transformation method for the diversion hydropower station system also includes the following steps: Step 1: After performing Step 4, obtain the intersection angle between the axial direction of the water supply pipe and the length direction of the dewatering river section by drawing a plan view. ; Step 2: Calculate the outlet flow velocity according to the following formulas. : ; in, It is the head loss along the route. It is a localized head loss, and , Calculate according to the following formulas respectively: λ× ; Where λ is the friction coefficient; ; in, It is the local loss coefficient; Step 3: Collect the average flow velocity of the dehydrated river section over one year. Then, compare it with the outlet flow rate. Compare the cosine components, if If cosθ, then repeat step four.

[0008] The angle between the axial direction of the water supply pipe and the length direction of the dehydration river section Satisfy the following relationship: 0° < <30°.

[0009] The local loss coefficient The value range is: 0.1 < <1.

[0010] The friction coefficient λ is calculated according to the following formula: ; Where Re is the Reynolds number, It is the kinematic viscosity of water at a water temperature of 20℃. =1.0×10⁻⁶ m² / s; when hour, ; when hour, ; when hour, ; in, It is the roughness of the inner wall surface of the water supply pipe.

[0011] The ecological restoration and transformation method for the diversion hydropower station system also includes the following steps: After performing step four, proceed according to the inlet elevation. The water supply pipe is constructed with a diameter D and a water level difference ∆H between the inlet and outlet. The inlet is connected to the upstream of the dam, and the outlet is connected to the dewatering section of the river.

[0012] The ecological restoration and renovation method of the water diversion power station system also includes the following steps: excavating and removing the soil and rocks near the water intake to form a buffer pool, and making the buffer pool adjacent to the upstream of the dam.

[0013] The ecological restoration and renovation method of the diversion power station system also includes the following steps: constructing a first cofferdam at the connection between the buffer pool and the upstream of the dam.

[0014] The ecological restoration and renovation method of the diversion-type power station system also includes the following steps: excavating and removing the soil and rocks near the outlet to form a stilling basin, and making the stilling basin adjacent to the dewatering river section.

[0015] The ecological restoration and renovation method of the diversion power station system also includes the following steps: constructing a second cofferdam at the connection between the stilling basin and the dewatering river section.

[0016] The beneficial effects of this invention are as follows: By adopting the technical solution of this invention, the water supply pipe and the power station operate independently of each other. Even if the power station stops operating, the water supply pipe can still maintain continuous operation, introducing part of the water flow upstream of the dam into the dewatering section, maintaining the basic needs of vegetation and organisms near the dewatering section, and maintaining the ecological balance. In addition, the inlet and outlet positions and pipe diameter of the water supply pipe have been calculated in detail, and a stable ecological flow can be maintained during the flood season, dry season, or freezing season. The location of the water supply pipe does not damage existing dams and other water conservancy facilities, and the construction is simple and convenient, eliminating safety hazards. Attached Figure Description

[0017] Figure 1 This is a plan view of the present invention.

[0018] In the diagram: 1-Water diversion tunnel, 2-Dam, 3-Dewatering section, 4-Water supply pipe, 5-Buffer pool, 6-First cofferdam, 7-Energy stilling basin, 8-Second cofferdam. Detailed Implementation

[0019] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0020] like Figure 1 As shown, this invention provides an ecological restoration and renovation method for a diversion-type hydropower station system, comprising the following steps: Step 1: Provide a water diversion power station system, which includes a power station, a water diversion tunnel 1, and a dam 2 set in the river channel. One end of the water diversion tunnel 1 is connected to the upstream of the dam 2, and the other end of the water diversion tunnel 1 is connected to the tailrace downstream of the dam 2. The power station is set in the middle of the water diversion tunnel 1. The river channel between the dam 2 and the tailrace is designated as the dewatering section 3. A water supply pipe 4 is designed between the upstream of the dam 2 and the dewatering section 3. The water supply pipe 4 and the water diversion tunnel 1 are respectively set on the left and right sides of the river channel, and one end of the water supply pipe 4 is used as the inlet and the other end of the water supply pipe 4 is used as the outlet. Step Two: Collect information on the flood season, freezing period, and aquatic organism types of the dewatering section 3 from Step One within one year, and preliminarily determine the ecological base flow rate of the water supply pipe 4 based on the above information. ; Step 3: Collect and obtain the normal water level elevation of Dam 2 from Step 1. and dead water level elevation The elevation of the inlet of water supply pipe 4 is calculated sequentially according to the following formulas. Functional head Inlet flow rate And pipe diameter D: ; in, ; = - ; ; in: It is the flow velocity coefficient, and ; ; Step 4: Initially determine the length L of the water supply pipe 4, the relative slope i between the axial direction of the water supply pipe 4 and the horizontal plane, and calculate the water level difference ∆H between the inlet and outlet according to the following formula: .

[0021] Using the technical solution of this invention, the water supply pipe and the power station operate independently of each other. Even if the power station stops operating, the water supply pipe can still maintain continuous operation, introducing a portion of the water flow upstream of the dam into the dewatering section of the river, maintaining the basic needs of vegetation and organisms near the dewatering section, and maintaining the ecological balance. In addition, the inlet and outlet positions and pipe diameter of the water supply pipe have been calculated in detail, ensuring a stable ecological flow discharge regardless of whether it is during the flood season, dry season, or freezing season. Furthermore, the location of the water supply pipe does not damage existing dams or other water conservancy facilities, making construction simple and convenient, and eliminating safety hazards.

[0022] Specifically, the ecological restoration and renovation methods for diversion-type hydropower systems also include the following steps: Step 1: After performing Step 4, obtain the intersection angle between the axial direction of the water supply pipe 4 and the length direction of the dewatering river section 3 by drawing a plan view. ; Step 2: Calculate the outlet flow velocity according to the following formulas. : ; in, It is the head loss along the route. It is a localized head loss, and , Calculate according to the following formulas respectively: λ× ; Where λ is the friction coefficient; ; in, It is the local loss coefficient; Step 3: Collect the average flow velocity of the river in section 3 of the dehydrated river in Step 1. Then, compare it with the outlet flow rate. Compare the cosine components, if If cosθ, then repeat step four.

[0023] By employing the technical solution of this invention, the average flow velocity of the river water is... With outlet flow velocity By comparing the cosine components, it is possible to avoid the impact of the water flow at the outlet on both banks of the dewatering section, prevent soil erosion on both banks of the dewatering section, and avoid excessive flow velocity at the outlet of the newly built ecological base flow discharge facility, which could damage various existing buildings on both banks of the dewatering section.

[0024] In addition, the angle between the axial direction of the water supply pipe 4 and the length direction of the dewatering river section 3 is... Satisfy the following relationship: 0° < <30°. Experience shows that when the angle between the axis of the water supply pipe 4 and the length direction of the dewatering section 3 is less than 30°. When the angle is less than 30°, the water flow at the outlet has less impact and damage on both banks of the dewatering section, thus eliminating safety hazards.

[0025] In addition, the local loss coefficient The value range is: 0.1 < <1. The friction coefficient λ is calculated according to the following formula: ; Where Re is the Reynolds number, It is the kinematic viscosity of water at a water temperature of 20℃. =1.0×10⁻⁶ m² / s; when hour, ; when hour, ; when hour, ; in, It refers to the roughness of the inner wall surface of the water supply pipe 4.

[0026] Specifically, the ecological restoration and renovation method for diversion-type hydropower station systems also includes the following steps: After performing step four, according to the intake elevation... Construct water supply pipe 4 with pipe diameter D and water level difference ∆H between inlet and outlet, and connect the inlet to the upstream of dam 2 and the outlet to the dewatering section 3.

[0027] In addition, the ecological restoration and renovation method for the diversion-type hydropower station system also includes the following steps: excavating and removing earth and rock near the intake to form a buffer pool 5. When constructing the buffer pool 5, excess water in the buffer pool 5 can be removed first by pumping facilities. The buffer pool 5 is used to initially buffer and dissipate energy for the water flow entering the water supply pipe 4. The ecological restoration and renovation method for the diversion-type hydropower station system also includes the following steps: constructing a first cofferdam 6 at the connection between the buffer pool 5 and the upstream of the dam 2. The first cofferdam 6 resists the impact force of the water flow inside the water supply pipe 4, further dissipating the energy of the water flow.

[0028] In addition, the ecological restoration and renovation method for the diversion-type hydropower station system also includes the following steps: excavating and removing earth and rock near the outlet to form a stilling basin 7, and ensuring that the stilling basin 7 is adjacent to the dewatering section 3 to prevent water from the outlet of the water supply pipe 4 from flowing back into the stilling basin 7 during the downstream construction of the dam, thus avoiding any impact on the construction process. The ecological restoration and renovation method for the diversion-type hydropower station system also includes the following steps: constructing a second cofferdam 8 at the connection between the stilling basin 7 and the dewatering section 3.

[0029] By adopting the technical solution of the present invention, the water flowing into the dewatering section of the river through the water supply pipe is subjected to two energy dissipation treatments by setting up a buffer pool 5 and an energy dissipation pool 7, thereby reducing the impact force of the water flow. Furthermore, by setting up a first cofferdam 6 and a second cofferdam 8, the impact force of the water flow is further reduced, thereby preventing the water flow from impacting the banks of the dewatering section and nearby buildings, preventing soil erosion, and reducing safety hazards.

Claims

1. A method of ecological rehabilitation of a run-of-river power plant system, characterized in that: Includes the following steps: Step 1: Provide a water diversion power station system, which includes a power station, a water diversion tunnel (1) and a dam (2) set in the river channel. One end of the water diversion tunnel (1) is connected to the upstream of the dam (2), and the other end of the water diversion tunnel (1) is connected to the tailrace downstream of the dam (2). The power station is set in the middle of the water diversion tunnel (1). The river channel between the dam (2) and the tailrace is designated as the dewatering section (3). A water supply pipe (4) is designed between the upstream of the dam (2) and the dewatering section (3). The water supply pipe (4) and the water diversion tunnel (1) are respectively set on the left and right sides of the river channel. One end of the water supply pipe (4) is designated as the inlet, and the other end of the water supply pipe (4) is designated as the outlet. Step two: collect the information of flood season time, freezing time and aquatic organism type of the de-watered river section (3) in a year, and preliminarily determine the ecological base flow of the water supplement pipe (4) according to the above information ; Step 3: Collect and obtain the normal water level elevation of the dam (2) mentioned in Step 1. and dead water level elevation The inlet elevation of the water supply pipe (4) is calculated sequentially according to the following formulas. Functional head Inlet flow rate And pipe diameter D: ； in, ; = - ； ； in: It is the flow velocity coefficient, and ; ； Step 4: Initially determine the length L of the water supply pipe (4), the relative slope i between the axial direction of the water supply pipe (4) and the horizontal plane, and calculate the water level difference between the inlet and outlet according to the following formula. H: ； The ecological restoration and transformation method of the water diversion power station system also includes the following steps: excavating and removing the soil and rock near the water intake to form a buffer pool (5), and making the buffer pool (5) adjacent to the upstream of the dam (2); constructing a first cofferdam (6) at the connection between the buffer pool (5) and the upstream of the dam (2). The ecological restoration and transformation method of the water diversion power station system also includes the following steps: excavating and removing the soil and rocks near the outlet to form a stilling pool (7), and making the stilling pool (7) adjacent to the dewatering section (3); constructing a second cofferdam (8) at the connection between the stilling pool (7) and the dewatering section (3).

2. The ecological restoration and renovation method for a diversion-type hydropower station system as described in claim 1, characterized in that: The ecological restoration and transformation method for the diversion hydropower station system also includes the following steps: Step 1: After performing step four, obtain the intersection angle between the axial direction of the water supply pipe (4) and the length direction of the dewatering river section (3) by drawing a plan view. ; Step 2: Calculate the outlet flow velocity according to the following formulas. : ; in, It is the head loss along the route. It is a localized head loss, and , Calculate according to the following formulas respectively: λ× ; Where λ is the friction coefficient; ； in, It is the local loss coefficient; Step 3: Collect the average flow velocity of the dehydrated river section (3) over one year. Then, combine it with the outlet flow rate. Compare the cosine components, if If cosθ, then repeat step four.

3. The ecological restoration and renovation method for a diversion-type hydropower station system as described in claim 2, characterized in that: The angle between the axial direction of the water supply pipe (4) and the length direction of the dewatering river section (3) Satisfy the following relationship: 0° < <30°.

4. The ecological restoration and renovation method for a diversion-type hydropower station system as described in claim 2, characterized in that: The local loss coefficient The value range is: 0.1 < <1.

5. The ecological restoration and renovation method for a diversion-type hydropower station system as described in claim 2, characterized in that: The friction coefficient λ is calculated according to the following formula: ； Where Re is the Reynolds number, It is the kinematic viscosity of water at a water temperature of 20℃. =1.0×10⁻⁶ m² / s; when hour, ; when hour, ; when hour, ; in, It is the roughness of the inner wall surface of the water supply pipe (4).

6. The ecological restoration and renovation method for a diversion-type hydropower station system as described in claim 1, characterized in that: The ecological restoration and transformation method for the diversion hydropower station system also includes the following steps: After performing step four, proceed according to the inlet elevation. Pipe diameter D, water level difference between the inlet and outlet The water supply pipe (4) is constructed and the water inlet is connected to the upstream of the dam (2), and the water outlet is connected to the dewatering section (3).

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