Are large‐scale flow experiments informing the science and management of freshwater ecosystems?

Abstract

Greater scientific knowledge, changing societal values, and legislative mandates have emphasized the importance of implementing large‐scale flow experiments (FEs) downstream of dams. We provide the first global assessment of FEs to evaluate their success in advancing science and informing management decisions. Systematic review of 113 FEs across 20 countries revealed that clear articulation of experimental objectives, while not universally practiced, was crucial for achieving management outcomes and changing dam‐operating policies. Furthermore, changes to dam operations were three times less likely when FEs were conducted primarily for scientific purposes. Despite the recognized importance of riverine flow regimes, four‐fifths of FEs involved only discrete flow events. Over three‐quarters of FEs documented both abiotic and biotic outcomes, but only one‐third examined multiple taxonomic responses, thus limiting how FE results can inform holistic dam management. Future FEs will present new opportunities to advance scientifically credible water policies.

Implications of water extraction on the low-flow hydrology and ecology of tropical savannah rivers: an appraisal for northern Australia

“…A range of approaches would be appropriate to fill these knowledge gaps. These approaches include field-based sampling along spatial and temporal hydrological gradients, monitoring of ecological responses to experimental flow manipulations (Konrad et al 2011, Olden et al 2014, and modelling approaches such as Bayesian Belief Network modeling that has the capacity to combine different types of knowledge and data (e.g., Chan et al 2012). However, each of these approaches has inherent strengths, weaknesses, and feasibility constraints in tropical savannah rivers.…”

The Brisbane Declaration and Global Action Agenda on Environmental Flows (2018)

“…Many have also expanded the scope of assessments from individual sites to whole river basin and regional scales (e.g., King and Brown, 2010;Buchanan et al, 2013;Hart, 2016a,b;O'Brien et al, 2017;Stein et al, 2017). Reflecting these developments, investments in large scale, collaborative e-flow strategies and experiments are increasing across developed and developing regions (e.g., Hirji and Davis, 2009;Konrad et al, 2011;Olden et al, 2014;Hart, 2016a,b;Kendy et al, 2017;Kennen et al, 2018). Parallel efforts have revitalized governance and management arrangements (Foerster, 2011;Pahl-Wostl et al, 2013;Garrick et al, 2017), and promoted multi-stakeholder alliances across researchers, water management agencies, industry, non-government organizations (NGOs), civil society and indigenous groups (Le Quesne et al, 2010;Conallin et al, 2017).…”

Quantifying flooding regime in floodplain forests to guide river restoration

“…The operation of flood control and other large dams has dramatically reduced peak flows, ultimately causing a decline in flood-dependent species (Dister et al, 1990;Auble et al, 2005;Frazier and Page, 2006;Burke et al, 2009;Stallins et al, 2010;Johnson et al, 2012). To help mitigate the loss of floodplain communities due Elementa: Science of the Anthropocene • 2: 000031 • doi: 10.12952/journal.elementa.000031 to flow regulation, many scientists, NGOs, and government agencies have proposed a full suite of potential solutions, including controlled flow releases to approximate natural flow regimes to help restore downstream in-channel and riparian ecological processes (Richter, 2010;Arthington, 2012;Olden et al, 2014;Warner et al, 2014).…”