Experimental Analysis of a Fish Guidance System for a River Water Intake

Gabriela Cîrciumaru,Ștefan-Mugur Simionescu,Andreea Voina,Lucian Mândrea,Lucia-Andreea El-Leathey,Rareș-Andrei Chihaia,Daniela-Elena Gogoașe Nistoran

doi:10.3390/w14030370

Abstract

This paper describes the experimental study of a behavioural barrier consisting of a bubble curtain placed near an ecological river water intake, aiming to assess the bubble curtain’s influence on the velocity field of water flowing in the water intake proximity. The scientific novelty is given by the water intake solution operating in tandem with the dedicated bubble curtain generator used for avoiding fish entrapment. The water intake solution used in the present research is based on a run-of-river intake without a dam in the riverbed, maintaining the mountain rivers longitudinal connectivity. An experimental setup was designed and built to study the behavioural barrier for ecological water intakes in different operating conditions. Thus, tests were performed for two water velocities (0.33 m/s and 0.535 m/s) in the experimental setup, two water depths (92 mm and 119 mm) and two air flow rates (10.5 LPM and 15 LPM). The results were compared with the case when no air is injected through the bubble curtain generator. The assessment of the bubble curtain influence on the water flow inside the channel was made by measuring and analysing the velocity variation in vertical and horizontal direction. The results showed a significant velocity gradient in the bubble curtain proximity, which can contribute to influencing the behaviour of the fish by deterring them from the water intake area.

Highlights

There are many issues that put the development of society in conflict with the sustainability and conservation of the environment, and one of them is given by the need to use water sources
Compared to traditional physical systems for fish guidance, the proposed behavioural barrier has the advantage to adapt to the flowing conditions of the river
The research presented in the paper approached the experimental study of a fish guidance system consisted of a bubble curtain for a river water intake to assess its influence on the water velocity field

Summary

Introduction

There are many issues that put the development of society in conflict with the sustainability and conservation of the environment, and one of them is given by the need to use water sources. The longitudinal hydrotechnical constructions (piers) prevented the lateral continuity of the river, as the flooding of the meadows could not take place and the ecological exchange of fertile material and aquatic flora/fauna between the rivers and wetlands in the major riverbeds could not be performed; this changed the hydrological regime [1], the morphology of the riverbed [6,7,8] and the structure of its bed substrate [8,9,10] Another negative impact on fish is created by the operation of water intakes located on rivers. The scientific novelty is given by the water intake solution operating in tandem with a dedicated bubble curtain generator which helps to avoid accidental entrapment of fish fauna

Fish Guidance Systems Based on the Use of Non-Physical Barriers

Results and Discussion

Conclusions