Prefabricated Fish Attraction Module Using Tailrace Outflow
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Solution Overview
Problem
Existing fish passage systems at hydropower facilities are costly and inefficient, particularly for small installations, as they require significant diversion of head pond flow for fish attraction, which competes with power generation and is often not sufficient to effectively attract fish.
Innovation Solution
The development of prefabricated fish passage attraction modules that redirect outflow from hydropower generators to create an attractor flow pattern, separating it from the fishway entry flow, thereby attracting fish volitionally without the need for auxiliary head pond flows or parasitic power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If head pond flow is diverted for fish attraction, then fish attraction capability is improved, but power generation efficiency deteriorates
Solution Approach 1:
The invention extracts the fish attraction function from the head pond flow system and implements it separately using tailrace outflow. The tailrace outflow is redirected through attractor nozzles to create attraction flow patterns, while the head pond flow remains dedicated to power generation, eliminating the conflict between fish attraction and power generation.
Solution Approach 2:
The tailrace outflow serves as an intermediary resource that is otherwise wasted. By capturing and redirecting this outflow through the attraction system, the invention creates fish attraction capability without consuming head pond flow that would otherwise be used for power generation.
2Reliability
If auxiliary head pond flows are used for fish attraction, then fish attraction effectiveness is improved, but system complexity and cost increase
Solution Approach 1:
The system uses the existing tailrace outflow from the hydropower facility itself to provide fish attraction. This self-service approach eliminates the need for external auxiliary water sources and reduces system complexity by utilizing resources already present in the facility.
Solution Approach 2:
The tailrace outflow, which would otherwise be discharged without purpose, is given a dual function: maintaining tailrace water levels and providing fish attraction flow. This multi-functionality reduces the need for separate auxiliary systems.
3Adaptability or versatility
If conventional fish passage systems are installed, then fish passage capability is improved, but cost increases significantly for small facilities
Solution Approach 1:
The invention employs simple, low-cost components such as attractor nozzles and flow deflectors that can be manufactured economically. These components create effective attraction flow patterns without requiring expensive conventional fish passage infrastructure, making the system affordable for small hydropower facilities.
Solution Approach 2:
The invention replaces complex mechanical fish passage systems with a hydraulic attraction system that uses flow patterns to guide fish. This substitution of mechanical structures with hydraulic guidance reduces construction and maintenance costs while maintaining fish passage capability.
4Adaptability or versatility
If tailrace outflow is redirected for attraction, then fish attraction is improved, but tailrace water level stability may deteriorate
Solution Approach 1:
The attraction system redirects only a portion of the tailrace outflow through specific attractor nozzles positioned to create localized attraction flow patterns. The majority of the tailrace outflow continues to discharge normally, maintaining overall water level stability while providing fish attraction where needed.
Solution Approach 2:
The system uses a partial amount of tailrace outflow for attraction purposes rather than redirecting the entire flow. This partial action approach ensures that sufficient water remains in the tailrace to maintain stable water levels while still providing effective fish attraction.
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
This solution provides a cost-effective and efficient method to attract a variety of fish species to fishways, reducing the financial burden on small hydropower facilities while ensuring effective fish passage, as it utilizes existing hydropower outflows to create attractive flow patterns.
Implementation Method 1
the adaptor having a tapered structure so as to alter first flow field and second flow field adjacent the downstream end
Data Source
AI summary
Zero-ascend omnispecies (ZAO) attraction system includes a fish passage attraction module that can be deployed in a fishway where water flows downstream. The fish passage attraction module includes a body having a first end and an opposite second end, first adaptor adjacent the first end and second adaptor adjacent the second end. The adaptors are configured to alter water flow fields downstream of the module so as to attract fish to an entrance thereof.