Fish Pass with Suction Pipe for Catadromous Migration
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Solution Overview
Problem
Existing fish passes do not allow complete passage for catadromous migratory fish to descend to salt water due to dam barriers, leading to trapped fish populations and disrupted migration instincts, particularly affecting adult eels and salmon smolts.
Innovation Solution
A fish pass design with water-permeable, meander-shaped passages and a suction pipe system that creates a controlled flow regime, guiding catadromous fish through the barrier wall via a pipe tunnel and aqueduct, utilizing pressure differences to attract fish and maintain a constant flow for migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional fish passes are used, then most fish species can ascend and descend, but catadromous migratory fish (eels, salmon smolts) cannot complete their migration to saltwater
Solution Approach 1:
The fish pass is divided into multiple functional sections: an upstream tower fish pass for ascending fish, a downstream tower fish pass for descending catadromous fish, and intermediate basins with controlled valves. This segmentation allows different water flow regimes to be created for different fish types, enabling both resident fish and catadromous migratory fish to use the structure effectively
Solution Approach 2:
The system employs dynamically controllable valves at different heights that can be adjusted based on water levels and migration needs. The control system activates specific valves to create appropriate flow conditions - for example, creating downward flowing water columns to attract eels during their catadromous migration, while maintaining suitable conditions for salmon smolts and resident fish at different times
2Reliability
If dams are built to control water levels, then water management is improved, but fish migration pathways are blocked
Solution Approach 1:
The tower fish pass structure serves multiple functions: it acts as a water level control mechanism for the dam, provides a migration pathway for ascending anadromous fish, enables descending catadromous fish passage through controlled downward flows, and can be adjusted to accommodate different water levels and migration seasons. This multi-functionality resolves the contradiction by making the dam structure itself serve both water management and fish migration needs
3Adaptability or versatility
If water flow is increased to maintain migration, then fish passage is improved, but energy consumption and water loss increase
Solution Approach 1:
The control system operates valves periodically based on migration patterns, water levels, and seasonal requirements rather than maintaining continuous high flow. During peak migration periods, specific valves are activated to create necessary flow conditions for catadromous fish. During non-migration periods or when water levels are low, the system reduces or redirects flow, minimizing energy consumption and water loss while still providing passage when needed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures the continuity of fish migration by allowing catadromous eels and salmon smolts to descend from reservoirs, ensuring the ecological balance and addressing the major fish ecological deficit caused by dams.
Implementation Method 1
A fish pass design with water-permeable, meander-shaped passages and a suction pipe system that creates a controlled flow regime, guiding catadromous fish through the barrier wall via a pipe tunnel and aqueduct, utilizing pressure differences to attract fish and maintain a constant flow for migration.
Data Source
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AI summary
The invention relates to a fish pass for overcoming a water level difference at a dam (1) of a reservoir, with an upper water inlet and a lower water outlet. The fish pass is divided into a waterside fish pass (2) and at least one further waterside fish pass (3), wherein the waterside fish pass (2) is connected to the waterside fish pass (3) via a pipe cross-tunnel (4) through the dam (1) and an aqueduct (5). From the bottom of the upstream water level (11) in front of the dam (1), a suction pipe (6) carries water to a descent control (23) at the lowest passage of the waterside fish pass (2), and this water flows further through a descent pipe (8) to the waterside fish passes and parallel to their passages into the downstream water level (12).The amount of water flowing through the descent pipe (8) is regulated by a gate (10) so that the descent pipe ensures a constant flow regime for the migrating catadromous fauna at all occurring water levels of the upstream water.