A hydrologic feature detection algorithm to quantify seasonal components of flow regimes

Patterson, Noelle K.; Lane, Belize; Sandoval-Solís, Samuel; Pasternack, G. B.; Yarnell, S. M.; Qiu, Yexuan

doi:10.1016/j.jhydrol.2020.124787

Cited by 27 publications

(43 citation statements)

References 67 publications

(82 reference statements)

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“…Section A of CEFF provides guidance for evaluating ecological flow needs based on natural functional flow metrics. Natural functional flow metrics have been quantified for all stream reaches in California (Patterson et al, 2020;Grantham et al, 2021). Reference expectations are generated by a statewide model of reference hydrology that is based on physical and climatic watershed characteristics and provide a consistent starting point for all environmental flow assessments.…”

Section: Ceff Section A-identify Ecological Flow Needs Based On Natural Functional Flowsmentioning

confidence: 99%

The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

Stein

Zimmerman

Yarnell

et al. 2021

Front. Environ. Sci.

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Environmental flow programs aim to protect aquatic habitats and species while recognizing competing water demands. Often this is done at the local or watershed level because it is relatively easier to address technical and implementation challenges at these scales. However, a consequence of this approach is that ecological flow criteria are developed for only a few areas as dictated by funding and interest with many streams neglected. Here we discuss the collaborative development of the California Environmental Flows Framework (CEFF) as an example process for developing environmental flow recommendations at a statewide scale. CEFF uses a functional flows approach, which focuses on protecting a broad suite of ecological, geomorphic, and biogeochemical functions instead of specific species or habitats, and can be applied consistently across diverse stream types and spatial scales. CEFF adopts a tiered approach in which statewide models are used to estimate ecological flow needs based on natural functional flow ranges, i.e., metrics that quantify the required magnitude, timing, duration, frequency, and/or rate-of-change of functional flow components under reference hydrologic conditions, for every stream reach in the state. Initial flow needs can then be revised at regional, or watershed, scales based on local constraints, management objectives, and available data and resources. The third tier of CEFF provides a process for considering non-ecological flow needs to produce a final set of environmental flow recommendations that aim to balance of all desired water uses. CEFF was developed via a broad inclusive process that included technical experts across multiple disciplines, representatives from federal and state agencies, and stakeholders and potential end-users from across the state. The resulting framework is therefore not associated with any single agency or regulatory program but can be applied under different contexts, mandates and end-user priorities. The inclusive development of CEFF also allowed us to achieve consensus on the technical foundations and commitment to applying this approach in the future.

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Section: Ceff Section A-identify Ecological Flow Needs Based On Natural Functional Flowsmentioning

confidence: 99%

The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

Stein

Zimmerman

Yarnell

et al. 2021

Front. Environ. Sci.

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“…For each feature, signatures are selected corresponding to flow magnitude, timing, frequency, duration, and/or rate of change. Online software is available to calculate these signatures in seasonal, Mediterranean climates (Patterson et al, 2020). Archfield, Kennen, Carlisle, and Wolock (2014) instead try to overcome subjectivity in signature choice by using their seven “fundamental daily streamflow statistics” for all rivers, including the moments of the flow series and descriptors of the seasonal cycle.…”

Section: Applications Of Hydrologic Signaturesmentioning

confidence: 99%

A review of hydrologic signatures and their applications

McMillan

2020

WIREs Water

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Hydrologic signatures are quantitative metrics or indices that describe statistical or dynamical properties of hydrologic data series, primarily streamflow. Hydrologic signatures were first used in eco-hydrology to assess alterations in flow regime, and have since seen wide uptake across a variety of hydrological fields. Their applications include extracting biologically relevant attributes of streamflow data, monitoring hydrologic change, analyzing runoff generation processes, defining similarity between watersheds, and calibrating and evaluating hydrologic models. Hydrologic signatures allow us to extract meaningful information about watershed processes from streamflow series, and are therefore seeing increasing use in emerging information-rich areas such as global-scale hydrologic modeling, machine learning, and large-sample hydrology. This overview paper describes the background and development of hydrologic signature theory, reviews hydrologic signature use across a variety of applications, and discusses ongoing hydrologic signature research including current challenges. This article is categorized under: Science of Water > Science of Water K E Y W O R D S flow indices, flow metrics, hydrologic signatures 1 | INTRODUCTION 1.1 | Discovering the information in streamflow data Streamflow timeseries show patterns: flood peaks and low flow periods, daily changes and seasonal cycles. These patterns are examples of information in streamflow data. The information might describe how the stream reacts to changes in weather, or what magnitudes and rates of change of flow are usual for the stream. Streamflow patterns depend on the physical characteristics of the watershed, telling a story about the path of water from precipitation to streamflow. Flow patterns in turn affect the stream's environment, informing us about riparian conditions and habitats. This paper describes how hydrologists use hydrologic signatures to extract this wealth of information from streamflow. 1.2 | What is a hydrologic signature? Hydrologic signatures are quantitative metrics that describe statistical or dynamic properties of streamflow. They are also known as hydrologic metrics, hydrologic indices, or diagnostic signatures. Hydrologic signatures range from simple

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“…Once the selected ASCI and CSCI sites were paired with proximal USGS sites, we calculated functional flow metrics (FFM) over the longest contiguous period of record for each USGS gage using the using the Functional Flows Calculator API client package in R (version 0.9.7.2) 1 , which uses hydrologic feature detection algorithms developed by Patterson et al (2020) and the Python functional flows calculator 2 . We calculated a normalized hydrologic alteration metric based on the departure from the predicted reference flow (difference between the observed FFM and the predicted [unimpaired reference condition] FFM) associated with the stream segment at the USGS gage (see Grantham et al this issue for additional details on how predicted reference-based functional flow metrics were modeled).…”

Section: Calculating Delta Hydrology Using Functional Flow Metricsmentioning

confidence: 99%

“…This could occur for several reasons, such as the data record was incomplete or the annual hydrograph was extremely different compared with the predicted reference condition. These instances would often lack a seasonal flow pattern that the flow calculator relies on to derive subsequent metrics (Patterson et al, 2020). If more than 70% of the annual values for a metric across the period of record at a gage were NA, then the flow alteration for that metric at that gage was not included in the dataset.…”

Section: Calculating Delta Hydrology Using Functional Flow Metricsmentioning

confidence: 99%

Identifying Functional Flow Linkages Between Stream Alteration and Biological Stream Condition Indices Across California

Peek

Irving

Yarnell

et al. 2022

Front. Environ. Sci.

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Large state or regional environmental flow programs, such as the one based on the California Environmental Flows Framework, rely on broadly applicable relationships between flow and ecology to inform management decisions. California, despite having high flow and bioassessment data density, has not established relationships between specific elements of the annual hydrograph and biological stream condition. To address this, we spatially and temporally linked USGS gage stations and biological assessment sites in California to identify suitable paired sites for comparisons of streamflow alteration with biological condition at a statewide scale. Flows were assessed using a set of functional flow metrics that provide a comprehensive way to compare alteration and seasonal variation in streamflow across different locations. Biological response was evaluated using the California Stream Condition Index (CSCI) and Algal Stream Condition Index (ASCI), which quantify biological conditions by translating benthic invertebrate or algal resources and watershed-scale environmental data into an overall measure of stream health. These indices provide a consistent statewide standard for interpreting bioassessment data, and thus, a means of quantitatively comparing stream conditions throughout the state. The results indicate that indices of biological stream condition were most closely associated with flow alteration in seasonality and timing metrics, such as fall pulse timing, dry-season timing, and wet season timing. Magnitude metrics such as dry-season baseflow, wet season baseflow, and the fall pulse magnitude were also important in influencing biological stream conditions. Development of ecological flow needs in large-scale environmental programs should consider that alteration to any of the seasonal flow components (e.g., dry-season baseflow, fall pulse flow, wet-season baseflow, spring recession flow) may be important in restructuring biological communities.

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A hydrologic feature detection algorithm to quantify seasonal components of flow regimes

Abstract: Highlights • A new signal processing algorithm identifies seasonal transitions from daily flow data. • Application to 223 unimpaired gages in California highlights algorithm performance. • Algorithm identifies statistically distinct seasonal timing across diverse flow regimes.

Cited by 27 publications

References 67 publications

The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

A review of hydrologic signatures and their applications

Identifying Functional Flow Linkages Between Stream Alteration and Biological Stream Condition Indices Across California

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