Implementing Environmental Flows in Complex Water Resources Systems – Case Study: The Duero River Basin, Spain

Abstract

European river basin authorities are responsible for the implementation of the new river basin management plans in accordance with the European Water Framework Directive. This paper presents a new methodology framework and approach to define and evaluate environmental flow regimes in the realistic complexities that exist with multiple water resource needs at a basin scale. This approach links river basin simulation models and habitat time series analysis to generate ranges of environmental flows (e-flows), which are evaluated by using habitat, hydropower production and reliability of water supply criteria to produce best possible alternatives.With the use of these tools, the effects of the proposed e-flows have been assessed to help in the consultation process. The possible effects analysed are impacts on water supply reliability, hydropower production and aquatic habitat. After public agreements, a heuristic optimization process was applied to maximize e-flows and habitat indicators, while maintaining a legal level of reliability for water resource demands. The final optimal e-flows were considered for the river basin management plans of the Duero river basin.This paper demonstrates the importance of considering quantitative hydrologic and ecological aspects of e-flows at the basin scale in addressing complex water resource systems. This approach merges standard methods such as physical habitat simulations and time series analyses for evaluating alternatives, with recent methods to simulate and optimize water management alternatives in river networks. It can be integrated with or used to complement other frameworks for e-flow assessments such as the In-stream Flow Incremental Methodology and Ecological Limits of Hydrologic Alteration.

A comparison of artificial neural networks and random forests to predict native fish species richness in Mediterranean rivers

“…The presented approaches, which relate environmental variables to the fish communities, can be used for predicting fish richness at the basin scale and can be incorporated into the decision-making process for water resources management (Paredes-Arquiola et al, in press). For instance they could contribute to perform large-scale assessments of environmental flow standards, based on methodological frameworks with a regional perspective (Poff et al, 2010;Paredes-Arquiola et al, 2013).…”

Application of the physical habitat simulation for fish species to assess environmental flows in an Atlantic Forest Stream in South-eastern Brazil

“…In this regard, the hydrological simulation of the stream basin will make possible to evaluate time series of WUA in a reference (natural) condition in comparison with different scenarios of regulation, water abstraction or climatic changes. These scenarios based on curves of total habitat, habitat duration curves and other indicators illustrated in specific documentation (Milhous et al, 1990;Bovee et al, 1998) have been incorporated in tools of e-flows (Payne & Jowett, 2012) and recently in decision support systems for water management (Paredes-Arquiola et al, 2013. The hydrological assessment will also allow the consideration of very important components of the flow regime, such as the flow pulses, the small floods and large floods, with specific importance for the conservation of the aquatic biodiversity.…”

Six decades of changes in the riparian corridor of a Mediterranean river: a synthetic analysis based on historical data sources

“…This constrained our reconstructed time series to a monthly resolution. This rather coarse temporal resolution is not ideal when investigating impacts on riparian systems because riparian vegetation is highly dependent on and responsive to shorter events, particularly droughts González et al, 2012) and floods (Blondel and Aronson, 1999;Naiman et al, 2008), which often form crucial elements in the definition of environmental flow regimes for riparian conservation Paredes-Arquiola et al, 2011). However, only monthly data are available for many rivers and regions (Richter et al, 2012), and in the present case, this was the highest resolution to which we felt able to construct an internally consistent flow series.…”