CN-117127547-B - Fish collecting system based on fish blocking weir

CN117127547BCN 117127547 BCN117127547 BCN 117127547BCN-117127547-B

Abstract

The invention discloses a fish collecting system based on a fish blocking weir, which is characterized in that after a tail water channel is divided into a thin-wall weir water channel and a fish collecting water channel, on one hand, the thin-wall weir has a certain height, so that fish is prevented from swimming into the thin-wall weir water channel from the thin-wall weir, and therefore, the fish only swims into a fish collecting tank of the fish collecting water channel, and on the other hand, the fish collecting system enables the water flow velocity flowing out of the fish collecting tank to be not greater than the swimming capability of the fish by designing the proper thin-wall weir height, so that most of the fish can swim without obstruction. The simple structure of the invention is suitable for river development hydroelectric power generation with small runoff, the cost investment is low, and the complex fish collecting and attracting system is not required to be redesigned.

Inventors

Hou Diequn
CHEN XIAOJUAN
ZHANG XIAOMIN
LI BAOTING
YU DELONG
ZHAI YONG
PAN CHAO
LI SHAOHUA

Assignees

水利部中国科学院水工程生态研究所
河南省出山店水库运行中心

Dates

Publication Date: 20260508
Application Date: 20230825

Claims (3)

1. A fish collecting system based on a fish blocking weir comprises a tail water channel of a hydropower station, wherein a diversion retaining wall is arranged in the tail water channel to divide the tail water channel into a fish collecting water channel and a thin-wall weir water channel with widths of B J and B Y respectively along the water flow direction, a thin-wall weir vertical to the water flow direction is arranged in the thin-wall weir water channel and used for blocking fish from flowing back and forth, and a fish collecting box is arranged in the fish collecting water channel along the water flow direction; The method is characterized in that the height of the thin-wall weir is designed according to the following steps: Step 1, firstly, assume that the thin wall weir height a= H0 ,H 0 is the upstream water level of the tail water channel, namely, assume that the thin wall weir upper head HY is 0, the thin wall weir water channel is completely blocked, water only flows into the downstream from the fish collecting water channel, the tail water channel flow Q is equal to the fish collecting water channel flow Q J , and the fish collecting water channel flow Q J is calculated according to a broadtop weir flow formula: (1) m is obtained by inquiring a flow coefficient table of a wide top weir with an inclined upstream surface or a flow coefficient table of a wide top weir without a bank, an upstream water head H J of the fish collecting canal is calculated according to the formula (1), the value of H 0 is obtained according to the assumed equal height of the upstream water head H J of the fish collecting canal and the height a of the thin wall weir, and the flow velocity V J =Q J /(B J *H J of the fish collecting canal is calculated; step 2, if V J exceeds the fish swimming speed, reducing the value of the height a of the thin-wall weir, and leading the water head H Y =H 0 -a on the thin-wall weir; According to a calculation formula of the thin wall weir canal flow Q Y , calculating the thin wall weir canal flow velocity V Y =Q Y /(H Y *B Y ): (2) (3) In order for the flow to be excessive, Is the flow coefficient, HY is the water head on the weir; Calculating the flow rate Q J =Q-Q Y of the fish collecting canal, then calculating H J according to the formula (1), and calculating the flow rate V J =Q J /(B J *H J of the fish collecting canal; Step 3, comparing Q (H Y +a)+ QV 2 /2 g and Q Y (H Y +a)+Q Y V Y 2 /2g+ Q J H J +Q J V J 2 /2g difference value according to the principle of energy conservation, if the difference value is positive value and the difference value is lower than the empirical value, conforming to the principle of energy conservation; Step 4, if the flow velocity V J of the fish collecting canal exceeds the fish swimming speed, reducing the value of the thin-wall weir height a, and repeating the steps 2-3 until the flow velocity V J of the fish collecting canal is smaller than the fish swimming speed and accords with the energy conservation law, so as to obtain the upper limit value of the thin-wall weir height; and 5, continuously reducing the thin-wall weir height, repeating the steps 2-3 until the flow velocity V J of the fish collecting channel is smaller than the fish swimming speed, conforming to the energy conservation rule, and enabling the upstream water head H J of the fish collecting channel to approach the designed lower limit value of the water level of the fish collecting channel to obtain the lower limit value of the thin-wall weir height.
2. The fish gathering system based on a fish barrage of claim 1, wherein if the thin wall barrage height obtained in step 5 is below a lower limit, the lower limit is taken as the thin wall barrage height lower limit.
3. The fish collecting system based on the fish blocking weir as claimed in claim 1, wherein a submerged fish collecting tank, a secondary fish inlet door, a primary fish inlet door, two side fixing piers and a bottom fixing base are arranged in the fish collecting canal, the primary fish inlet door and the secondary fish inlet door are both of an eight-shaped grid structure and can penetrate water flow, the outlet of the fish collecting tank is provided with an inverted horn mouth, the upper part of the fish collecting tank is of a permeable grid structure, the lower part of the fish collecting tank is of a water impermeable tank, the water impermeable tank is partially embedded into a fish collecting water canal bottom plate, two sides of the fish collecting tank are fixed with a wall body of a basic structure through the fixing piers, and water flow can penetrate through the fish collecting tank, and m=0.385.

Description

Fish collecting system based on fish blocking weir Technical Field The invention relates to the field of hydraulic engineering and environmental protection engineering, in particular to a fish collecting system based on a fish blocking weir. Background The hydropower station blocks the migration of fishes at the upstream and downstream of a river and influences the migration behavior and gene communication of the fishes, so that the hydropower station is provided with a fish gathering and transporting system and a fish lift, and the fishes are transported at the upstream and downstream of a dam manually so as to promote the communication of fish populations and maintain the ecological balance of the aquatic products. The fish gathering and attracting device is an important component of the fish gathering and attracting system and the fish lifting machine, determines the effectiveness of the whole system, and can only act if the fish gathering and attracting device traps enough fishes. Various fish gathering and attracting methods exist, such as light, food, water flow conditions and the like, in engineering, a fish gathering and attracting device usually uses water flow to induce fish to swim in, as shown in fig. 5, the fish gathering and attracting device is usually placed in a tail water channel of a hydropower station, the tail water channel of a miniature hydropower station is narrowed, an outlet of the fish gathering and attracting device 5 is constructed to be a horn-shaped fish inlet door, the fish inlet door is as wide as the tail water channel, and power generation tail water in the tail water channel is utilized to form fish gathering and attracting water flow in the fish gathering and attracting device 5 and near a fish inlet, so that fish is induced to swim into the fish gathering and attracting device 5 along the fish inlet door. The flow rate of the miniature hydropower station is large, and the water level of the tail water channel is high after the design of narrowing the tail water channel, so that a high water head difference exists between the upstream and downstream in the tail water channel, the flow rate of water is too fast, and fish cannot swim into the fish gathering and attracting device. Disclosure of Invention The invention provides a fish collecting system based on a fish blocking weir, which aims to solve the problems that the current flow rate of a fish collecting system and other drainage channels greatly exceeds the swimming capacity of fish and the flow rate of the fish tends to flow into a water channel with high flowing speed, and when the flow rate of the other drainage channels is greater than the flow rate of the fish collecting system, the fish cannot be induced into the fish collecting water channel. The fish collecting system based on the fish blocking weir comprises a tail water channel of a hydropower station, wherein a diversion retaining wall is arranged in the tail water channel to divide the tail water channel into a fish collecting water channel and a thin-wall weir water channel with widths of B J and B Y respectively along the water flow direction, a thin-wall weir vertical to the water flow direction is arranged in the thin-wall weir water channel and used for blocking fish from flowing back in a reverse flow manner, and a fish collecting box is arranged in the fish collecting water channel along the water flow direction; The height of the thin-wall weir is designed according to the following steps: Step 1, firstly, assuming that the thin wall weir height a=h 0,H0 is the upstream water level of the tail water channel, namely assuming that the thin wall weir upper head H Y is 0, the thin wall weir water channel is completely blocked, water only flows into the downstream from the fish collecting water channel, the tail water channel flow Q is equal to the fish collecting water channel flow Q J, and the fish collecting water channel flow Q J is calculated according to a wide top weir flow formula: m is obtained by inquiring a flow coefficient table of a wide top weir with an inclined upstream surface or a flow coefficient table of a wide top weir without a bank, an upstream water head H J of the fish collecting canal is calculated according to the formula (1), the value of H 0 is obtained according to the assumed equal height of the upstream water head H J of the fish collecting canal and the height a of the thin wall weir, and the flow velocity V J＝QJ/(BJ*HJ of the fish collecting canal is calculated; Step 2, if V J exceeds the fish swimming speed, reducing the value of the height a of the thin-wall weir, and leading the water head H Y＝H0 -a on the thin-wall weir; according to a calculation formula of the thin wall weir canal flow Q Y, calculating the thin wall weir canal flow velocity V Y＝QY/(HY*BY): Q Y is the overcurrent flow, m 0 is the flow coefficient, and H Y is the weir upper head; Calculating the flow rate Q J＝Q-QY of the fish collecting canal, then