Single-outlet fishway and fish passing method using tail water of ecological unit

Abstract

The present application provides a single-outlet fishway and fish passing method using tail water of ecological unit, which sequentially sets fishway downstream shallow water section, fishway overflow section and fishway upstream deep water section in communication from downstream to upstream; installs fishway inlet rectifying building in the outside area of fishway inlet; fishway overflow section is the transition section of fishway upstream deep water section and fishway downstream shallow water section, which is used for adjusting the water level of fishway upstream deep water section and fishway downstream shallow water section, so that the fishway upstream deep water section and fishway downstream shallow water section smoothly connect and transition. The fishway inlet of the present application uses tail water of ecological unit and abandoned water of fishway overflow section to lure fish; the fishway outlet adopts single outlet, which solves the problems of complex water supply system construction of fishway inlet and multiple fishway outlets which must be set when the water level of upstream varies, realizes the non-gate control of fishway operation, and further saves the fishway construction investment, improves the fishway operation management level and fish passing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of hydropower engineering technology, specifically relating to a single-outlet fishway and fish passage method utilizing the tailwater of an ecological unit. Background Technology

[0002] Fishways, as artificial passageways for fish to migrate upstream through dams and other hydropower structures, play a vital ecological role in mitigating the obstructive effects of dams and facilitating their normal life activities. However, to accommodate significant upstream water level fluctuations, many existing hydropower fishway projects in China have multiple outlets at different locations and elevations. For example, the Dadu River Zhentouba I Hydropower Station has three fishway outlets to accommodate reservoir changes. Multiple-outlet fishways not only incur high investment costs but also present numerous operational and management challenges. The frequent switching of outlet gates severely impacts the fishway's passage efficiency. Furthermore, to enhance fish attraction at the fishway inlet, existing hydropower projects in China often incorporate fish attraction and replenishment systems, such as the Niyang River Duobu Hydropower Station. While these systems improve fish attraction at the inlet, they also increase the complexity of fishway operation and management, as well as investment costs. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a single-outlet fishway and fish passage method utilizing the tailwater of an ecological unit, which can effectively solve the above-mentioned problems.

[0004] The technical solution adopted in this invention is as follows:

[0005] The present invention provides a single-outlet fishway utilizing the tailwater of an ecological unit, wherein a shallow water section (1) downstream of the fishway, an overflow section (2) and a deep water section (3) upstream of the fishway are sequentially connected from downstream to upstream.

[0006] The shallow water section (1) downstream of the fishway is a normal fishway, which allows fish to swim upstream and rest. Its downstream port forms the fishway inlet (4), and its upstream port is connected to the downstream port of the fishway overflow section (3).

[0007] The overflow section (2) of the fishway is a transition section between the upstream deep water section (3) and the downstream shallow water section (1) of the fishway. It is used to adjust the water level of the upstream deep water section (3) and the downstream shallow water section (1) of the fishway so that the water flow of the upstream deep water section (3) and the downstream shallow water section (1) of the fishway can be smoothly connected and transitioned. The upstream port of the overflow section (2) of the fishway is connected to the downstream port of the upstream deep water section (3) of the fishway.

[0008] The upstream deep-water section (3) of the fishway is a normal fishway, which is used for fish to swim upstream and stay and rest. Its upstream port is a single outlet of the fishway (5), which can adapt to the large water level fluctuation of the upstream reservoir.

[0009] Preferably, a fishway inlet straightening structure (6) is installed in the outer region of the fishway inlet (4);

[0010] The fishway inlet rectifier structure (6) is an ecological unit tailwater rectifier device used to create a fish-attracting water flow at the fishway inlet;

[0011] The fishway inlet rectifying structure (6) has a fish-attracting water flow channel (6-1); one end of the fish-attracting water flow channel (6-1) is the tailwater inlet of the ecological unit, and the other end is the tailwater outlet of the ecological unit. The tailwater outlet of the ecological unit is close to the fishway inlet (4), so that an accelerated fish-attracting water flow is formed at the fishway inlet (4).

[0012] From the tailwater inlet of the ecological unit to the tailwater outlet of the ecological unit, the width of the fish-attracting water flow channel (6-1) gradually decreases.

[0013] Preferably, the fishway inlet straightening structure (6) includes a tailrace sidewall (6-2), a diversion pier (6-3), an inclined guide wall (6-4), and a straight guide wall (6-5);

[0014] According to the tailwater flow direction of the ecological unit, the diversion pier (6-3), the inclined guide wall (6-4) and the straight guide wall (6-5) are sequentially connected to form a diversion guide wall;

[0015] The fish-attracting water flow channel (6-1) is formed between the tailrace wall (6-2) and the diversion guide wall.

[0016] Preferably, the diversion pier (6-3) has a diversion pier angle α, and the diversion water volume of the tailwater of the ecological unit is controlled by the diversion pier angle α to form a fish-attracting water flow;

[0017] The inclined guide wall (6-4) has an inclined guide wall angle β, which guides the direction of the fish-attracting water flow formed by the diversion pier (6-3) through the inclined guide wall angle β;

[0018] The straight guide wall (6-5) is used to stabilize the fish-attracting water flow passing through the inclined guide wall (6-4);

[0019] The width of the ecological unit tailwater inlet of the fish-attracting water channel (6-1) is a1, and the width of the ecological unit tailwater outlet is b1, where a1 = 3b1. The flow rate of the fish-attracting water is adjusted by the difference between the width of the ecological unit tailwater inlet and the width of the ecological unit tailwater outlet.

[0020] Preferably, the downstream shallow water section (1) of the fishway includes a fishway general pool chamber (1-1) and a fishway resting pool chamber (1-2);

[0021] After several levels of the fishway ordinary pool chambers (1-1) are connected in series, a fishway resting pool chamber (1-2) is connected in series; then several levels of the fishway ordinary pool chambers (1-1) are connected in series, and then a fishway resting pool chamber (1-2) is connected in series, and so on, to form the downstream shallow water section (1) of the fishway formed by the fishway ordinary pool chambers (1-1) and the fishway resting pool chambers (1-2) connected in series;

[0022] Wherein: the bottom slope J2 of the fishway resting pool (1-2) is less than the bottom slope J1 of the fishway ordinary pool (1-1), so that the water flow velocity in the fishway resting pool (1-2) is lower than the water flow velocity in the fishway ordinary pool (1-1), providing a resting space for fish to swim upstream.

[0023] Preferably, both the fishway ordinary pool chamber (1-1) and the fishway resting pool chamber (1-2) include multiple sets of baffle assemblies arranged at intervals along the counter-current direction of the water flow;

[0024] Each of the baffle assemblies includes a fishway partition (1-3) and a fishway guide (1-4) arranged in a relatively staggered manner; a vertical slit (1-5) is formed between the fishway partition (1-3) and the fishway guide (1-4) to allow fish to stably swim upstream, the vertical slit (1-5) having a vertical slit guide angle γ.

[0025] Preferably, the vertical slit guide angle γ is 45°.

[0026] Preferably, the fishway overflow section (2) includes an overflow pool (2-1), an overflow side weir (2-2), a fish barrier net (2-3), and a wastewater pipe (2-4);

[0027] Inside the overflow pool (2-1), two overflow side weirs (2-2) are arranged opposite each other; a fish passage is formed between the two overflow side weirs (2-2); and a fish-blocking net (2-3) is fixedly installed above each of the overflow side weirs (2-2).

[0028] An overflow space (2-5) is formed between each of the overflow side weirs (2-2) and the sidewall of the overflow pool (2-1);

[0029] One end of the wastewater discharge pipe (2-4) is connected to the overflow space (2-5), and the other end of the wastewater discharge pipe (2-4) is connected to the tailwater inlet of the ecological unit in the fish-attracting water flow channel (6-1). Through the wastewater discharge pipe (2-4), the wastewater from the overflow side weir (2-2) is led to the tailwater inlet of the ecological unit, so that the wastewater and the tailwater of the ecological unit together form a fish-attracting water flow.

[0030] Preferably, the upstream deep-water section (3) of the fishway includes multiple deep-water fishway ordinary pool chambers and multiple deep-water fishway resting pool chambers;

[0031] After several levels of the ordinary pool rooms of the deep-water fishway are connected in series, a resting pool room of the deep-water fishway is connected in series; then several levels of the ordinary pool rooms of the deep-water fishway are connected in series, and then a resting pool room of the deep-water fishway is connected in series, and so on, to form the upstream deep-water section (3) of the fishway.

[0032] This invention also provides a method for fish passage using a single-outlet fishway of an ecological unit's tailwater, comprising the following steps:

[0033] Step 1: Water Level Adjustment Phase

[0034] The water level in the upstream reservoir fluctuates between 1.0 and 6.0 m. The operating water depth of the deep water section (3) upstream of the fishway is between 1.0 and 7.0 m. After being regulated by the overflow section (2) of the fishway, the water depth is reduced to 1.0 m and flows to the shallow water section (1) downstream of the fishway. At this time, the operating water depth of the shallow water section (1) downstream of the fishway is 1.0 m.

[0035] Among them: when the deep water section (3) upstream of the fishway is running at a high water level, the water level of the deep water section (3) upstream of the fishway and the shallow water section (1) downstream of the fishway are smoothly connected through the adjustment of the overflow section (2) of the fishway. The overflow water of the overflow section (2) is introduced into the tailwater channel of the ecological unit through the wastewater pipe (2-4) and forms a fish-attracting water flow together with the tailwater of the ecological unit.

[0036] When the deep water section (3) of the upstream fishway is running at a low water level, the overflow section (2) of the fishway does not overflow, and the deep water section (3) of the upstream fishway is smoothly connected to the shallow water section (1) of the downstream fishway through a section of backwater.

[0037] Step 2: Fish Attraction Stage

[0038] The wastewater discharged from the tailwater of the ecological unit and the wastewater discharged from the overflow section (2) of the fishway flows together through the fishway inlet rectification structure (6). Through the diversion effect of the diversion pier (6-3), the guiding effect of the inclined guide wall (6-4), and the stabilizing effect of the straight guide wall (6-5) of the fishway inlet rectification structure (6), a stable fish-attracting water flow is formed in the straight guide wall (6-5), creating a good fish-attracting flow field, so that fish can flow into the shallow water section (1) downstream of the fishway through the fishway inlet (4);

[0039] Step 3: After passing through the shallow water section (1) downstream of the fishway, the overflow section (2) of the fishway, and the deep water section (3) upstream of the fishway in sequence, the fish flow out from the single outlet (5) of the fishway.

[0040] The single-outlet fishway and fish passage method utilizing the tailwater of an ecological unit provided by this invention have the following advantages:

[0041] The fishway inlet utilizes the tailwater from the ecological unit and the overflow section of the fishway to attract fish; the fishway outlet adopts a single outlet, which solves the problems of constructing a complex water replenishment system at the fishway inlet and having to set up multiple fishway outlets when the upstream water level fluctuates. This achieves gateless control of the fishway operation. At the same time, the shallow section of the fishway uses low side walls, which further saves investment in fishway construction and improves the level of fishway operation and management and fish passage efficiency. Attached Figure Description

[0042] Figure 1 This invention provides an overall structural diagram of a single-outlet fishway utilizing the tailwater of an ecological unit;

[0043] Figure 2 A perspective view of the fishway inlet rectifier structure provided by the present invention;

[0044] Figure 3 A top view of the fishway inlet rectifier structure provided by the present invention;

[0045] Figure 4 A simplified three-dimensional view of the downstream shallow water section, the overflow section, and the upstream deep water section of the fishway provided by the present invention;

[0046] Figure 5 A simplified top view of the downstream shallow water section, the overflow section, and the upstream deep water section of the fishway provided by the present invention;

[0047] Figure 6 A simplified side view of the downstream shallow water section, the overflow section, and the upstream deep water section of the fishway provided by the present invention;

[0048] Figure 7 A perspective view of a typical fish passage chamber provided by the present invention;

[0049] Figure 8 A top view of a typical fishway chamber provided by the present invention;

[0050] Figure 9 A top view of the fishway resting pool provided by the present invention;

[0051] Figure 10 A schematic diagram of the upstream deep-water section and downstream shallow-water section of the fishway provided by the present invention during high-water-level overflow operation;

[0052] Figure 11 This is a schematic diagram of the upstream deep water section and downstream shallow water section of the fishway provided by the present invention during low water level overflow operation. Detailed Implementation

[0053] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the invention.

[0054] This invention proposes a single-outlet fishway utilizing the tailwater of an ecological generator unit for the construction of fish passage facilities in hydropower projects. It enables the fishway outlet to be gate-free, requiring only a single outlet. Furthermore, by using the tailwater of the ecological generator unit and the overflow section of the fishway to attract fish, it reduces the need for a complex fish attraction and water replenishment system at the fishway inlet, thereby reducing investment in fishway construction, improving fish passage efficiency, and facilitating fishway operation and management.

[0055] The main concept of this invention is as follows: the fishway, from downstream to upstream, comprises: a fishway inlet rectifying structure, a shallow downstream section, a fishway overflow section, a deep upstream section, and a single outlet. The fishway utilizes the inlet rectifying structure to regulate the wastewater from the ecological power generation unit and the overflow section, creating favorable flow conditions at the fishway inlet to attract fish and reducing the need for a complex water replenishment system at the inlet. Simultaneously, the overflow section regulates the operating water levels of the deep upstream section and the shallow downstream section, achieving a smooth transition between them and solving the problem of having to install multiple outlets when the upstream water level fluctuates significantly. This single-outlet fishway fully utilizes the wastewater from the ecological power generation unit, achieving gateless operation, greatly improving fishway efficiency, and saving on construction investment.

[0056] refer to Figure 1 The present invention provides a single-outlet fishway utilizing the tailwater of an ecological unit, wherein a shallow water section 1 downstream of the fishway, an overflow section 2, and a deep water section 3 upstream of the fishway are sequentially connected from downstream to upstream.

[0057] The shallow water section 1 downstream of the fishway is a normal fishway, which allows fish to swim upstream and rest. Its downstream port forms the fishway inlet 4, and its upstream port is connected to the downstream port of the fishway overflow section 3.

[0058] The overflow section 2 of the fishway is a transition section between the deep water section 3 upstream of the fishway and the shallow water section 1 downstream of the fishway. It is used to adjust the water level of the deep water section 3 upstream of the fishway and the shallow water section 1 downstream of the fishway, so that the water flow of the deep water section 3 upstream of the fishway and the shallow water section 1 downstream of the fishway can be smoothly connected and transitioned. The upstream port of the overflow section 2 of the fishway is connected to the downstream port of the deep water section 3 upstream of the fishway.

[0059] The upstream deep-water section 3 of the fishway is a normal fishway, providing a place for fish to swim upstream and rest. Its upstream end is the single outlet 5 of the fishway, which is the upstream outlet for fish to swim upstream and adapt to the large water level fluctuations of the upstream reservoir.

[0060] Install the fishway inlet rectifier 6 in the outer area of ​​the fishway inlet 4.

[0061] The following is a detailed introduction to each part:

[0062] (I) Fishway Inlet Rectifier Structure 6

[0063] The fishway inlet rectifier 6 is installed in the external area of ​​the fishway inlet 4. It is an ecological unit tailwater rectifier device used to create a fish-attracting water flow at the fishway inlet.

[0064] Combination Figure 2 and Figure 3 The fishway inlet rectifying structure 6 has a fish-attracting water flow channel 6-1; one end of the fish-attracting water flow channel 6-1 is the tailwater inlet of the ecological unit, and the other end is the tailwater outlet of the ecological unit. The tailwater outlet of the ecological unit is close to the fishway inlet 4, so that an accelerated fish-attracting water flow is formed at the fishway inlet 4.

[0065] From the tailwater inlet of the ecological unit to the tailwater outlet of the ecological unit, the width of the fish-attracting water flow channel 6-1 gradually decreases.

[0066] Specifically, the fishway inlet rectification structure 6 includes tailrace channel sidewall 6-2, diversion pier 6-3, inclined guide wall 6-4, and straight guide wall 6-5;

[0067] According to the tailwater flow direction of the ecological unit, the connected diversion piers 6-3, inclined guide walls 6-4 and straight guide walls 6-5 are set in sequence to form a diversion guide wall;

[0068] A fish-attracting water flow channel 6-1 is formed between the tailrace wall 6-2 and the diversion guide wall.

[0069] As a specific implementation method, the diversion pier 6-3 has a diversion pier angle α. By controlling the diversion pier angle α, the tailwater flow of the ecological unit is controlled, and a fish-attracting water flow is formed on the fishway inlet side; the length of the diversion pier 6-3 is l1.

[0070] The inclined guide wall 6-4 has an angle β, which guides the direction of the fish-attracting water flow formed by the diversion pier 6-3; the length of the inclined guide wall 6-4 is l2;

[0071] The straight guide wall 6-5 is used to stabilize the fish-attracting water flow passing through the inclined guide wall 6-4; the length of the straight guide wall 6-5 is l3;

[0072] The width of the tailwater inlet of the ecological unit in the fish-attracting water flow channel 6-1 is a1, and the width of the tailwater outlet of the ecological unit is b1, where a1 = 3b1. The flow rate of the fish-attracting water flow is adjusted by the difference between the width of the tailwater inlet and the width of the tailwater outlet of the ecological unit.

[0073] (II) Shallow section downstream of the fishway 1

[0074] The shallow water section 1 downstream of the fishway includes a fishway general pool chamber 1-1 and a fishway resting pool chamber 1-2, which provide a place for fish to swim upstream and stay and rest. Figure 7 and Figure 8 This is a structural diagram of the ordinary pond chamber 1-1 of the fish passage; Figure 9 This is a structural diagram of the fishway resting pool.

[0075] After several levels of fishway ordinary pool chambers 1-1 are connected in series, a fishway resting pool chamber 1-2 is connected in series; then several levels of fishway ordinary pool chambers 1-1 are connected in series, then a fishway resting pool chamber 1-2 is connected in series, and so on, forming the downstream shallow water section 1 of the fishway formed by the fishway ordinary pool chambers 1-1 and the fishway resting pool chambers 1-2 connected in series.

[0076] Among them, the bottom slope J2 of the fishway resting pool 1-2 is less than the bottom slope J1 of the fishway ordinary pool 1-1, so that the water flow velocity of the fishway resting pool 1-2 is lower than that of the fishway ordinary pool 1-1, providing a resting space for fish to swim upstream.

[0077] In this invention, both the fishway ordinary pool chamber 1-1 and the fishway resting pool chamber 1-2 include multiple sets of baffle assemblies arranged at intervals along the counter-current direction of water flow.

[0078] Each baffle assembly includes a fishway partition 1-3 and a fishway guide 1-4 that are relatively staggered; a vertical slit 1-5 is formed between the fishway partition 1-3 and the fishway guide 1-4 to allow fish to stably swim upstream, and the vertical slit 1-5 has a vertical slit guide angle γ. For example, the vertical slit guide angle γ is 45°.

[0079] As a specific implementation method, both the fishway ordinary pool chamber 1-1 and the fishway resting pool chamber 1-2 are composed of two fishway partitions 1-3 and two fishway guide plates 1-4.

[0080] The dimensions of the fishway ordinary tank chamber 1-1 are B1 × A1 (length × width), with a slope of J1 and a vertical joint width of C1. The width A2 of the fishway resting tank chamber 1-2 is the same as the width A1 of the fishway ordinary tank chamber 1-1. The length of the fishway resting tank chamber 1-2 is B2, and the bottom slope is J1. 2. The vertical slit width is C2; the fishway partitions 1-3 and 1-4 have the same thickness, d, and the vertical slit widths C1 and C2 are the same; the length of the fishway guide 1-4 is P, and the relationship between the guide length P and the width of the pool chamber is P / A1 = 0.20~0.30. A stable fish upstream passage is formed between the two vertical slits in each pool chamber, and the vertical slit guiding angle γ = 45°. In practical applications, a fishway resting pool chamber 1-2 can be set up every 20 levels of ordinary fishway pool chamber 1-1. The relationship between the length and bottom slope of the fishway resting pool chamber 1-2 and the length and bottom slope of the ordinary pool chamber is: B2 = 2B1; J 2.=J1 / 2. The flow rate in the fishway resting pool 1-2 is regulated by J2 to provide resting space for fish to move upstream.

[0081] (III) Fishway Overflow Section 2

[0082] The overflow section 2 of the fishway serves as a transition section between the shallow water section 1 downstream of the fishway and the deep water section 3 upstream of the fishway. It plays a role in adjusting the water level of the deep water section 3 upstream of the fishway and the shallow water section 1 downstream of the fishway, so that the water flow of the deep water section 3 upstream of the fishway and the shallow water section 1 downstream of the fishway can be smoothly connected.

[0083] Combination Figure 4 , Figure 5 and Figure 6 The fishway overflow section 2 includes an overflow pool 2-1, an overflow side weir 2-2, a fish barrier net 2-3, and a wastewater pipe 2-4;

[0084] Inside the overflow pool 2-1, two overflow side weirs 2-2 are set opposite each other; a fish passage is formed between the two overflow side weirs 2-2; a fish-blocking net 2-3 is fixedly installed above each overflow side weir 2-2;

[0085] An overflow space 2-5 is formed between the sidewall of each overflow side weir 2-2 and the overflow pool 2-1;

[0086] One end of the wastewater discharge pipe 2-4 is connected to the overflow space 2-5, and the other end of the wastewater discharge pipe 2-4 is connected to the tailwater inlet of the ecological unit in the fish-attracting water flow channel 6-1. Through the wastewater discharge pipe 2-4, the wastewater from the overflow side weir 2-2 is led to the tailwater inlet of the ecological unit, so that the wastewater and the tailwater of the ecological unit together form a fish-attracting water flow.

[0087] Specifically, the elevation h1 between the crest of the side weir and the top of the side wall; the wastewater pipe 2-4 is used to collect the wastewater from the overflow side weir 2-2, with its lower end 1m away from the power generation water level of the ecological unit's tailrace channel, and the distance c between the water supply pipe and the inlet rectifying structure, forming a fish-attracting flow together with the tailrace of the ecological unit, with a pipe diameter φ; at the same time, to prevent fish from jumping out of the overflow pool 2-1, a fish-blocking net 2-3 is installed on top of the overflow side weir 2-2. When the deep water section of the fishway is operating at a high water level, the double overflow side weirs are used to adjust the connection between the deep water section and the shallow water section of the fishway. A collection pool is set up outside the overflow water from the overflow side weirs, and the collected water is introduced into the tailrace channel of the ecological unit through the wastewater pipe, forming a new fish-attracting flow after passing through the diversion pier; when the deep water section of the fishway is operating at a low water level, the double overflow side weirs will not overflow, and the upstream deep water section is smoothly connected to the downstream shallow water section through a section of backwater.

[0088] (iv) Deep water section upstream of the fishway 3

[0089] The upstream deep-water section 3 of the fishway includes multiple deep-water fishway ordinary pool rooms and multiple deep-water fishway resting pool rooms;

[0090] After several stages of deep-water fishway ordinary pool rooms are connected in series, a deep-water fishway resting pool room is connected in series; then several stages of deep-water fishway ordinary pool rooms are connected in series, and then a deep-water fishway resting pool room is connected in series, and so on, to form the upstream deep-water section 3 of the fishway.

[0091] In this invention, the structure of the upstream deep-water section 3 of the fishway is the same as the structure and principle of the downstream shallow-water section 1 of the fishway, and will not be described again here.

[0092] This invention also provides a method for fish passage using a single-outlet fishway of an ecological unit's tailwater, comprising the following steps:

[0093] Step 1: Water Level Adjustment Phase

[0094] The water level in the upstream reservoir fluctuates between 1.0 and 6.0 m. The operating water depth of the deep water section 3 upstream of the fishway is between 1.0 and 7.0 m. After being regulated by the overflow section 2 of the fishway, the water depth is reduced to 1.0 m and flows to the shallow water section 1 downstream of the fishway. At this time, the operating water depth of the shallow water section 1 downstream of the fishway is 1.0 m.

[0095] Among them: such as Figure 10 As shown, when the deep water section 3 upstream of the fishway is running at a high water level, the water levels of the deep water section 3 upstream of the fishway and the shallow water section 1 downstream of the fishway are smoothly connected through the adjustment of the overflow section 2 of the fishway. The overflow water from the overflow section 2 of the fishway is introduced into the tailwater channel of the ecological unit through the wastewater pipe 2-4, and together with the tailwater of the ecological unit, they form a fish-attracting water flow.

[0096] like Figure 11 As shown, when the upstream deep water section 3 of the fishway is operating at a low water level, the overflow section 2 of the fishway does not overflow, and the upstream deep water section 3 of the fishway is smoothly connected to the downstream shallow water section 1 of the fishway through a section of backwater.

[0097] Step 2: Fish Attraction Stage

[0098] The tailwater of the ecological unit and the wastewater discharged from the overflow section 2 of the fishway through the overflow pipe 2-4 flow together through the fishway inlet rectifying structure 6. Through the diversion effect of the diversion pier 6-3 of the fishway inlet rectifying structure 6, the guiding effect of the inclined guide wall 6-4, and the stabilizing effect of the straight guide wall 6-5, a stable fish-attracting water flow is formed at the straight guide wall 6-5, creating a good fish-attracting flow field, so that fish can flow into the shallow water section 1 of the downstream of the fishway through the fishway inlet 4.

[0099] Step 3: After passing through the shallow water section 1 downstream of the fishway, the overflow section 2 of the fishway, and the deep water section 3 upstream of the fishway in sequence, the fish flow out from the single outlet 5 of the fishway.

[0100] The following is a specific example:

[0101] The power station adopts a hybrid development approach, consisting of the headworks (dam, right bank spillway and sediment flushing outlet, riverbed dam body overflow outlet, left bank downstream ecological powerhouse, fish passage structure), right bank underground water diversion system, and downstream surface powerhouse. The dam is a concrete gravity dam with a maximum height of 67 meters and a total reservoir capacity of 121 million cubic meters. 3 As a daily regulating reservoir, the upstream water level fluctuates by 3 meters. The design of the fish passage facilities should be able to adapt to the changes in the reservoir water level during the operation of the power station.

[0102] To adapt to significant changes in upstream water levels, the fishway pattern of "using ecological unit tailwater + overflow pool + single outlet" provided by this invention is adopted. After adopting this arrangement, the original design length of the fishway of 1800m is shortened to 1400m, saving engineering work.

[0103] A single-outlet fishway utilizing the tailwater of an ecological unit to adapt to upstream water level fluctuations, comprising, from downstream to upstream: a fishway inlet rectifying structure 6, a shallow downstream section 1, a fishway overflow section 2, a deep upstream section 3, and a single fishway outlet 5.

[0104] Among them, the fishway inlet rectification structure 6 includes tailrace channel sidewall 6-2, diversion pier 6-3, inclined guide wall 6-4 and straight guide wall 6-5;

[0105] The angle α of the diversion pier is 20°, the angle β of the inclined guide wall is 36°, the length l2 of the inclined guide wall 6-4 is 16.34m, the length l3 of the straight guide wall 6-5 is 25m, the inlet width a of the rectifier structure is 15m, and the outlet width b is 5m.

[0106] The downstream shallow water section 1 of the fishway consists of a general fishway chamber 1-1 and a resting fishway chamber 1-2. The general fishway chamber 1-1 has a length B1 of 2.25m, a width A1 of 2.0m, a slope of 2.76%, a partition thickness of 0.2m, a vertical joint width C1 of 0.3m, and a guide angle of 45°. The resting fishway chamber 1-2 has a length B2 of 4.5m, a width A2 of 2.0m, a partition thickness of 0.2m, a vertical joint width C2 of 0.3m, a guide angle of 45°, and a bottom slope of 1.4%.

[0107] The fishway overflow section 2 includes an overflow pool 2-1, an overflow side weir 2-2, a fish barrier net 2-3, and a wastewater pipe 2-4. The overflow pool 2-1 has dimensions of 12m × 9.2m × 4.5m (length × width × depth). The top of the overflow side weir 2-2 is 0.4m above the top of the side wall. The wastewater pipe 2-4 has a diameter of 100mm and its lower end is 1m above the water level of the tailwater channel of the ecological generator unit. The water supply pipe is 10m away from the inlet rectifier structure and together with the tailwater of the ecological generator unit, they form a fish-attracting water flow.

[0108] The upstream deep-water section 3 of the fishway consists of a regular fishway chamber and a resting fishway chamber. The regular fishway chamber measures 2.25m × 2.0m × 4.5m (length × width × height) with a slope of 2.76%. The resting fishway chamber measures 4.5m × 2.0m × 4.5m (length × width × height) with a bottom slope of 1.4%.

[0109] The fishway has a single outlet 5 with a flat bottom. The bottom elevation is 1.0m lower than the dead water level of 3203m in the reservoir area, and the bottom elevation is 3202m.

[0110] The operation and management steps of this fishway are as follows:

[0111] (1) Water level adjustment phase:

[0112] The water level in the upstream reservoir ranges from 3203m to 3206m, with a variation of 1.0 to 4.0m. The operating water depth of the deep water section 3 upstream of the fishway is 1.0 to 4.0m. After the overflow section 2 of the fishway discharges water through the side weir, the water depth drops to 1.0m and flows to the shallow water section 1 downstream of the fishway. At this time, the operating water depth of the shallow water section 1 downstream of the fishway is 1.0m.

[0113] (2) Fish attraction stage:

[0114] The wastewater discharged from the tailwater of the ecological unit and the wastewater pipes 2-4 of the fishway overflow section 2 flows out through the fishway inlet rectifier 6 to attract fish, creating a good flow field at the fishway inlet, and the fish enter the downstream inlet of the fishway.

[0115] Repeat the above steps to keep the fishway working continuously.

[0116] The fish passageway chamber and overflow tank 2-1 shall meet the following control conditions:

[0117] (1) The flow velocity at the vertical gap of the fishway shall not exceed 1.2 m / s;

[0118] (2) The operating water depth of the shallow water section 1 downstream of the fishway is designed to be 1.0m, and the operating water depth of the deep water section 3 upstream of the fishway is 1.0m to 4.0m;

[0119] (3) The water level fluctuation at the upstream outlet of the fishway shall not exceed 3m.

[0120] The main hydraulic parameters of the fishway operation are shown in Table 1. As can be seen from Table 1, the water level variation at the fishway outlet reservoir is 4m, the operating water depth in the upstream deep section is 1m to 4m, the operating water depth in the downstream shallow section is 1m, and the flow velocity at the vertical joint of the fishway is 0.6m / s to 1.2m / s, which meets the requirements for fish to swim upstream.

[0121] Table 1 shows the main hydraulic characteristics of the fishway operation.

[0122]

[0123] The benefits of this invention are:

[0124] The fishway inlet utilizes the tailwater from the ecological unit and the overflow section of the fishway to attract fish; the fishway outlet adopts a single outlet, which solves the problems of constructing a complex water replenishment system at the fishway inlet and having to set up multiple fishway outlets when the upstream water level fluctuates. This achieves gateless control of the fishway operation. At the same time, the shallow section of the fishway uses low side walls, which further saves investment in fishway construction and improves the level of fishway operation and management and fish passage efficiency.

[0125] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A single-outlet fishway utilizing the tailwater of an ecological unit, characterized in that, The fishway is connected from downstream to upstream in the following order: the downstream shallow water section (1), the fishway overflow section (2), and the upstream deep water section (3). The shallow water section (1) downstream of the fishway is a normal fishway, which allows fish to swim upstream and rest. Its downstream port forms the fishway inlet (4), and its upstream port is connected to the downstream port of the fishway overflow section (2). The overflow section (2) of the fishway is a transition section between the upstream deep water section (3) and the downstream shallow water section (1) of the fishway. It is used to adjust the water level of the upstream deep water section (3) and the downstream shallow water section (1) of the fishway so that the water flow of the upstream deep water section (3) and the downstream shallow water section (1) of the fishway can be smoothly connected and transitioned. The upstream port of the overflow section (2) of the fishway is connected to the downstream port of the upstream deep water section (3) of the fishway. The upstream deep water section (3) of the fishway is a normal fishway, which is used for fish to swim upstream and stay and rest. Its upstream port is a single outlet of the fishway (5), which can adapt to the large water level fluctuation of the upstream reservoir. Among them, a fishway inlet rectifier (6) is installed in the outer region of the fishway inlet (4). The fishway inlet rectifier structure (6) is an ecological unit tailwater rectifier device used to create a fish-attracting water flow at the fishway inlet; The fishway inlet rectifying structure (6) has a fish-attracting water flow channel (6-1); one end of the fish-attracting water flow channel (6-1) is the tailwater inlet of the ecological unit, and the other end is the tailwater outlet of the ecological unit. The tailwater outlet of the ecological unit is close to the fishway inlet (4), so that an accelerated fish-attracting water flow is formed at the fishway inlet (4). From the tailwater inlet of the ecological unit to the tailwater outlet of the ecological unit, the width of the fish-attracting water flow channel (6-1) gradually decreases; The fishway inlet straightening structure (6) includes a tailrace sidewall (6-2), a diversion pier (6-3), an inclined guide wall (6-4), and a straight guide wall (6-5). According to the tailwater flow direction of the ecological unit, the diversion pier (6-3), the inclined guide wall (6-4) and the straight guide wall (6-5) are sequentially connected to form a diversion guide wall; The fish-attracting water flow channel (6-1) is formed between the tailwater channel sidewall (6-2) and the diversion guide wall. The diversion pier (6-3) has a diversion pier angle α. The diversion pier angle α controls the amount of tailwater flowing from the ecological unit, forming a fish-attracting water flow. The inclined guide wall (6-4) has an inclined guide wall angle β, which guides the direction of the fish-attracting water flow formed by the diversion pier (6-3) through the inclined guide wall angle β; The straight guide wall (6-5) is used to stabilize the fish-attracting water flow passing through the inclined guide wall (6-4); The width of the ecological unit tailwater inlet of the fish-attracting water channel (6-1) is a1, and the width of the ecological unit tailwater outlet is b1, where a1=3b1. The flow rate of the fish-attracting water is adjusted by the difference between the width of the ecological unit tailwater inlet and the width of the ecological unit tailwater outlet.

2. The single-outlet fishway utilizing the tailwater of an ecological unit according to claim 1, characterized in that, The downstream shallow water section (1) of the fishway includes a fishway general pool chamber (1-1) and a fishway resting pool chamber (1-2). After several levels of the fishway ordinary pool chambers (1-1) are connected in series, a fishway resting pool chamber (1-2) is connected in series; then several levels of the fishway ordinary pool chambers (1-1) are connected in series, and then a fishway resting pool chamber (1-2) is connected in series, and so on, to form the downstream shallow water section (1) of the fishway formed by the fishway ordinary pool chambers (1-1) and the fishway resting pool chambers (1-2) connected in series. Wherein: the bottom slope J2 of the fishway resting pool (1-2) is less than the bottom slope J1 of the fishway ordinary pool (1-1), so that the water flow velocity in the fishway resting pool (1-2) is lower than the water flow velocity in the fishway ordinary pool (1-1), providing a resting space for fish to swim upstream.

3. A single-outlet fishway utilizing the tailwater of an ecological unit according to claim 2, characterized in that, Both the fishway ordinary pool chamber (1-1) and the fishway resting pool chamber (1-2) include multiple sets of baffle assemblies arranged at intervals along the counter-current direction of water flow; Each of the baffle assemblies includes a fishway partition (1-3) and a fishway guide (1-4) arranged in a relatively staggered manner; a vertical slit (1-5) is formed between the fishway partition (1-3) and the fishway guide (1-4) to allow fish to stably swim upstream, the vertical slit (1-5) having a vertical slit guide angle γ.

4. A single-outlet fishway utilizing the tailwater of an ecological unit according to claim 3, characterized in that, The vertical slit guide angle γ is 45°.

5. A single-outlet fishway utilizing the tailwater of an ecological unit according to claim 1, characterized in that, The fishway overflow section (2) includes an overflow pool (2-1), an overflow side weir (2-2), a fish barrier net (2-3), and a wastewater pipe (2-4). Inside the overflow pool (2-1), two overflow side weirs (2-2) are arranged opposite each other; a fish passage is formed between the two overflow side weirs (2-2); and the fish-blocking net (2-3) is fixedly installed above each of the overflow side weirs (2-2). An overflow space (2-5) is formed between each of the overflow side weirs (2-2) and the sidewall of the overflow pool (2-1). One end of the wastewater discharge pipe (2-4) is connected to the overflow space (2-5), and the other end of the wastewater discharge pipe (2-4) is connected to the tailwater inlet of the ecological unit in the fish-attracting water flow channel (6-1). Through the wastewater discharge pipe (2-4), the wastewater from the overflow side weir (2-2) is led to the tailwater inlet of the ecological unit, so that the wastewater and the tailwater of the ecological unit together form a fish-attracting water flow.

6. A single-outlet fishway utilizing the tailwater of an ecological unit according to claim 1, characterized in that, The upstream deep-water section (3) of the fishway includes multiple deep-water fishway ordinary pool rooms and multiple deep-water fishway resting pool rooms; After several levels of the ordinary pool rooms of the deep-water fishway are connected in series, a resting pool room of the deep-water fishway is connected in series; then several levels of the ordinary pool rooms of the deep-water fishway are connected in series, and then a resting pool room of the deep-water fishway is connected in series, and so on, to form the upstream deep-water section (3) of the fishway.

7. A method for passing fish using a single-outlet fishway of an ecological unit tailwater as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Water Level Adjustment Phase The water level in the upstream reservoir fluctuates between 1.0 and 6.0 m. The operating water depth of the deep water section (3) upstream of the fishway is 1.0 to 7.0 m. After being regulated by the overflow section (2) of the fishway, the water depth is reduced to 1.0 m and flows to the shallow water section (1) downstream of the fishway. At this time, the operating water depth of the shallow water section (1) downstream of the fishway is 1.0 m. Among them: when the deep water section (3) upstream of the fishway is running at a high water level, the water level of the deep water section (3) upstream of the fishway and the shallow water section (1) downstream of the fishway are smoothly connected through the adjustment of the overflow section (2) of the fishway. The overflow water of the overflow section (2) is introduced into the tailwater channel of the ecological unit through the wastewater pipe (2-4) and forms a fish-attracting water flow together with the tailwater of the ecological unit. When the deep water section (3) of the fishway is running at a low water level, the overflow section (2) of the fishway does not overflow, and the deep water section (3) of the fishway is smoothly connected to the shallow water section (1) of the fishway by a section of backwater. Step 2: Fish Attraction Stage The wastewater discharged from the tailwater of the ecological unit and the wastewater discharged from the overflow section (2) of the fishway flows together through the fishway inlet rectification structure (6). Through the diversion effect of the diversion pier (6-3), the guiding effect of the inclined guide wall (6-4), and the stabilizing effect of the straight guide wall (6-5) of the fishway inlet rectification structure (6), a stable fish-attracting water flow is formed at the straight guide wall (6-5), creating a good fish-attracting flow field, so that fish can flow into the shallow water section (1) of the downstream of the fishway through the fishway inlet (4). Step 3: After passing through the shallow water section (1) downstream of the fishway, the overflow section (2) of the fishway, and the deep water section (3) upstream of the fishway in sequence, the fish flow out from the single outlet (5) of the fishway.

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