Design of a paired-weir system for experimental manipulation of environmental flows in streams

Abstract

Controlled in-stream flow manipulations are challenging but necessary to implement to assess the consequences of real-world flow alterations on aquatic ecosystems. We designed a double v-notch weir system, which was first prototype-tested in a laboratory flume and then in the field. The device diverted instantaneous flows proportionally in a robust way (e.g., 10% of flow in the stream main channel and 90% of flow into the diversion channel). We tested diversions systematically and evaluated how well flows matched our target flow-percentages. This is one of the first ecohydraulic structures designed and tested to experimentally manipulate environmental flows in small upland streams.

Keywords:

• Environmental flows
• experimental
• manipulation
• structure
• in-stream

Acknowledgements

The development of this work was part of the project "Développer des solutions pour la gestion durable et adaptative des ressources en eau dans les páramos de la ville de Quito (Équateur)" - CHALPI-FLOW - funded by the Agence Française pour le Développement (AFD), in collaboration with the French Institute for a sustainable Development (IRD, convention n° 2017000345). Special thanks to Karl Pendleton for building the prototype and help with laboratory installation and to Dimitri Agurto and Xavier Valdivieso for assistance in the field.

Disclosure statement

No potential conflict of interest was reported by the authors.