Optimization tools for environmental water decisions: A review of strengths, weaknesses, and opportunities to improve adoption

Horne, Avril; Szemis, Joanna; Kaur, Simranjit; Webb, J.; Stewardson, Michael J.; Costa, Alysson M.; Boland, Natashia

doi:10.1016/j.envsoft.2016.06.028

Cited by 53 publications

(45 citation statements)

References 83 publications

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“…Standards based on fixed percentages of mean annual flow (MAF) (e.g., [24,25]) have been criticized for failure to protect the components of natural flow regimes that are of primary ecological importance [2,5,22], yet are still widely employed globally [22,26]. The tendency for water-management decisions to be inadequately informed by environmental flows research is an example of the larger disconnect between conservation science and practice [17,27,28].…”

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

“…One class of environmental flows studies that is explicitly geared toward decision-support involves optimization, by which pre-defined mathematical rules are applied to identify an "optimal" solution to meet an ecological objective [17,43]. Unfortunately, optimization approaches commonly fall short of evaluating ecological responses to hydrologic alteration (e.g., [44,45]) and instead present results only in terms of flow indices, which are implicitly assumed to be acceptable surrogates for ecological outcomes [17].…”

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

“…In response to these challenges, decision-support systems (DSS) informed by environmental flows science offer a range of potential benefits to water-resource management-such as by improving the transparency, objectivity, and efficiency of the decision-making process-but are currently not widely applied [17][18][19][20]. In practice, many water-resource decisions are made in an ad hoc fashion, using experience-based rather than evidence-based approaches [21,22].…”

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

“…For example, recent applications of the ELOHA framework have either produced flow-ecology relationships [36][37][38][39] or have prescribed general flow standards for particular river systems [40,41] but have not provided objective, quantitative frameworks for translating particular water-management decisions (e.g., withdrawal permits, and dam releases) into predicted hydrologic or ecological outcomes. Although substantial science exists on ecological effects of flow alteration [16,42], this understanding is often not specific enough to be readily translated into usable DSS [17], such that the "implementation" phase of ELOHA (lower left corner of figure 1 in [31]) remains a challenge. Thus, an important link to connect environmental flows science to real-world decision-making requires the application of generalized flow-ecology relationships to site-specific predictions of ecological response to particular proposed flow alterations.…”

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

“…However, the cumulative effects on aquatic communities of many such incremental alterations may become substantial when multiplied over entire river basins [1,[33][34][35]. Similarly, reservoir release management typically involves a series of many short-term decisions (e.g., release of a flood pulse for a given duration on a given day), the cumulative effects of which may produce long-term ecological consequences [17]. The Ecological Limits of Hydrologic Alteration (ELOHA) [31] is commonly cited as a general framework for discerning flow-ecology relationships, but it provides little guidance on how these relationships can be operationalized to support specific and localized water-management decisions.…”

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

See 4 more Smart Citations

Putting Flow–Ecology Relationships into Practice: A Decision-Support System to Assess Fish Community Response to Water-Management Scenarios

Cartwright

Caldwell

Nebiker

et al. 2017

Water

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This paper presents a conceptual framework to operationalize flow-ecology relationships into decision-support systems of practical use to water-resource managers, who are commonly tasked with balancing multiple competing socioeconomic and environmental priorities. We illustrate this framework with a case study, whereby fish community responses to various water-management scenarios were predicted in a partially regulated river system at a local watershed scale. This case study simulates management scenarios based on interactive effects of dam operation protocols, withdrawals for municipal water supply, effluent discharges from wastewater treatment, and inter-basin water transfers. Modeled streamflow was integrated with flow-ecology relationships relating hydrologic departure from reference conditions to fish species richness, stratified by trophic, reproductive, and habitat characteristics. Adding a hypothetical new water-withdrawal site was predicted to increase the frequency of low-flow conditions with adverse effects for several fish groups. Imposition of new reservoir release requirements was predicted to enhance flow and fish species richness immediately downstream of the reservoir, but these effects were dissipated further downstream. The framework presented here can be used to translate flow-ecology relationships into evidence-based management by developing decision-support systems for conservation of riverine biodiversity while optimizing water availability for human use.

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Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

Section: Needs and Challenges Of Decision-support Systems For Water-rmentioning

confidence: 99%

See 3 more Smart Citations

Putting Flow–Ecology Relationships into Practice: A Decision-Support System to Assess Fish Community Response to Water-Management Scenarios

Cartwright

Caldwell

Nebiker

et al. 2017

Water

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Nonlinear survival of imperiled fish informs managed flows in a highly modified river

et al. 2021

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Water is a fundamental resource in freshwater ecosystems, and streamflow plays a pivotal role in driving riverine ecology and biodiversity. Ecologically functional flows, managed hydrographs that are meant to reproduce the primary components of the natural hydrograph, are touted as a potential way forward to restore ecological functions of highly modified rivers, while also balancing human water needs. A major challenge in implementing functional flows will be establishing the shape of the managed hydrograph so as to optimize improvements to the ecosystem given the limited resources. Identifying the shape of the flow-biology relationship is thus critical for determining the environmental consequences of flow regulation. In California's Central Valley, studies have found that increased streamflow can improve survival of imperiled juvenile salmon populations during their oceanward migration. These studies have not explored the potential nonlinearities between flow and survival, giving resource managers the difficult task of designing flows intended to help salmon without clear guidance on flow targets. We used an information theoretic approach to analyze migration survival data from 2436 acoustic-tagged juvenile Chinook salmon from studies spanning differing water years (2013)(2014)(2015)(2016)(2017)(2018)(2019) to extract actionable information on the flow-survival relationship. This relationship was best described by a step function, with three flow thresholds that we defined as minimum (4259 cfs), historic mean (10,712 cfs), and high (22,872 cfs). Survival varied by flow threshold: 3.0% below minimum, 18.9% between minimum and historic mean, 50.8% between historic mean and high, and 35.3% above high. We used these thresholds to design alternative hydrographs over the same years that included an important component of functional flows: spring pulse flows. We compared predicted cohort migration survival between actual and alternative hydrographs. Managed hydrographs with pulse flows that targeted high survival thresholds were predicted to increase annual cohort migration survival by 55-132% without any additions to the water budget and by 79-330% with a modest addition to the water budget. These quantitative estimates of the biological consequences of different flow thresholds provide resource managers with critical information for designing functional flow regimes that benefit salmon in California's highly constrained water management arena.

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Re‐operating dams for environmental flows: From recommendation to practice

Owusu

Mul

Zaag

et al. 2020

River Research & Apps

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Dam construction and operation are known to alter the hydrology of rivers and degrade riverine ecosystems. In recent decades, the call to reverse these negative impacts by re‐operating dams has become stronger. Dams can support riverine ecosystems by releasing environmental flows (e‐flows). Unfortunately, despite the development of numerous methodologies to determine e‐flows and optimise dam releases, actual implementation has not followed suit. Integrating e‐flow requirements in the design of new dams is relatively easier than changing operations of existing dams; however, re‐operating existing dams is essential to restore ecosystems and ecosystem services that have already been affected by the construction and operation of dams. This study provides insights into how e‐flows evolve from recommendation to practice through a systematic literature review on practical experiences to integrate e‐flows in dam operations. Sixty‐nine cases of successful dam re‐operation have been identified, ranging from the well‐documented case of the Glen Canyon Dam in the United States to less known cases such as the Katse Dam in Lesotho. We find that the most important factors that facilitate the successful implementation of e‐flows are the existence of e‐flows legislation or policy, the development of a research base in the form of an environmental impact study, and then flow experimentation. Illustrations of the important role of collaboration between various stakeholders and set timelines for implementation of recommendations are also given. These insights will inform how existing dams can be re‐operated and governed more equitably and sustainably for both humans and the environment.

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Optimization tools for environmental water decisions: A review of strengths, weaknesses, and opportunities to improve adoption

Cited by 53 publications

References 83 publications

Putting Flow–Ecology Relationships into Practice: A Decision-Support System to Assess Fish Community Response to Water-Management Scenarios

Putting Flow–Ecology Relationships into Practice: A Decision-Support System to Assess Fish Community Response to Water-Management Scenarios

Nonlinear survival of imperiled fish informs managed flows in a highly modified river

Re‐operating dams for environmental flows: From recommendation to practice

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