Defining environmentally acceptable flow downstream intake structures in Croatia

Abstract

Determining minimum water flows that will continuously run through a natural channel downstream of a water intake (Q0) is a multidisciplinary problem. It is, however, not approached in a multidisciplinary way in most countries. This paper offers an overview of the main methods and proposes a practical and environmentally more acceptable way of determining the retained flow, namely the environmentally acceptable flow (EAF). It is proposed that until the conditions are created for use of more complex methods and/or biological response techniques, the EAF be defined by determining whether the retained flow is sufficient for sustaining and developing indigenous wildlife in the streams by ensuring of the essential living conditions for the bioindicator species. The proposed bioindicators are characteristic fish populations of a specific type of stream and stream reaches. Being the final link in the ecological food chain, fish species are reliable indicators of bioecological balance in a stream.

Shrinking Pareto Fronts to Guide Reservoir Operations by Quantifying Competition Among Multiple Objectives

“…Fish have a high trophic level in aquatic ecosystems, and their population size and species richness reflect the changes in the aquatic ecosystems (Mišetić et al., 2003; Wu et al., 2014; Zhao et al., 2015). In some systems, fish spawning coincides with the onset of flooding, and they gather at the spawning grounds to lay eggs when the flood increases and leave after it finishes (Tao et al., 2017).…”

“…Consequently, the construction and operation of reservoirs affect the ecosystem, mainly manifesting as changes in hydrological conditions downstream. In most cases, the human-controlled discharge process is more stable, altering the flow regime formed by long-term natural evolution that is required by downstream aquatic ecosystems, thus endangering them (Jiang et al, 2019).Fish have a high trophic level in aquatic ecosystems, and their population size and species richness reflect the changes in the aquatic ecosystems (Mišetić et al, 2003;Wu et al, 2014;Zhao et al, 2015). In some systems, fish spawning coincides with the onset of flooding, and they gather at the spawning grounds to lay eggs when the flood increases and leave after it finishes (Tao et al, 2017).…”