Gregory Brian Pasternack

Gregory Brian Pasternack
University of California, Davis | UCD · Department of Land, Air and Water Resources

PhD

About

245
Publications
46,003
Reads
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4,651
Citations
Introduction
I aim to help society manage and restore hydrogeomorphic processes in support of enhanced ecosystem functioning. Working with others, I do this through a combination of basic physical and ecological science to understand how the naturally complex landscape works and technology transfer to get the methods we develop into the hands of practitioners, regulators, and stakeholders. Teaching, service, and outreach are also important.
Additional affiliations
September 1998 - present
University of California, Davis
Position
  • Professor (Full)
Education
January 1995 - June 1998
Johns Hopkins University
Field of study
  • Geography and Environmental Engineering
August 1993 - December 1994
University of California, Berkeley
Field of study
  • Water Resources Engineering
July 1989 - May 1993
Wesleyan University
Field of study
  • (1) Earth & Environmental Science; (2) Science and Society Program

Publications

Publications (245)
Article
Full-text available
Macro-roughness elements such as boulders and bedrock outcrops, collectively referred to as large bed elements (LBEs), are key features influencing hydrodynamics and morphodynamics in mountain rivers. Where LBEs are abundant and account for a substantial portion of total flow resistance, existing geomorphic theory, previous physical experiments, an...
Article
Full-text available
Reservoir sedimentation management has become an important topic for large dams in the United States due to their historical design, current age, and increased environmental regulation. Less attention has been paid to small dams (hydraulic size < 0.01) in remote mountains with urgent sedimentation problems. In drier climates, such reservoirs may be...
Technical Report
Full-text available
This report presents 13 planning-level designs of potential habitat enhancement projects n the Lower Yuba River, California, USA. In addition, it provides planing-level analyses of some of the ecological benefits and financial costs, along with a prioritization of the projects on those bases.
Article
Full-text available
The morphological unit (MU) characterizes river landforms at the scale of ~0.5–5 channel widths. Geomorphic theory posits that ceteris paribus under a stationary flow and sediment regime, a river's channel pattern and its MU assemblage will also be stationary. This study tested that conjecture for the dynamic, gravel/cobble lower Yuba River. The MU...
Article
Full-text available
Substrate facies monitoring is critical for the understanding of fluvial geomorphologic and ecohydraulic patterns and processes. However, direct substrate measurement is time-consuming and subjected to data sparsity because of small sample, size, and limited data collections within an area of interest, which make it difficult to capture facies patt...
Poster
Full-text available
The alteration of flow regimes and landscapes has led to a decline in riparian forests across western North America. River restoration designs often include plantings to address the loss of riparian vegetation. Plant survival may be assessed based on estimated groundwater and scour dynamics. Plantings are labor intensive, expensive to implement, an...
Conference Paper
Reservoir sedimentation management has become an important topic to large dams in the United States due to their historical design, current age, and increased environmental regulation. Less attention has been paid to small dams in remote mountains even though they are facing a more urgent sedimentation problem due to their relatively small storage....
Article
Full-text available
Plain Language Summary Deep pools and shallow riffles occur in most river systems and are formed through an interaction between the water flowing through a river and the sediment it carries and deposits. Several more technical hypotheses have been developed as to why pools and riffles form where they do. The original hypothesis, called the velocity...
Article
Full-text available
Relationships between fluvial aquatic habitat availability and discharge are often assumed to remain static when used with hydrologic datasets to analyze changes in habitat availability over time. Despite this assumption, studies have observed significant changes in aquatic habitat availability before and after restoration projects, dam removals, a...
Article
Full-text available
Given the complex array of processes influencing river networks, conceptual frameworks of rivers are critical to our understanding of channel processes and response potential as well as restoration efforts. Yet despite their wide usage, many classifications are based on limited observations over homogenous landscapes, raising questions about their...
Article
Full-text available
Floods play a critical role in geomorphic change, but whether peak magnitude, duration, volume, or frequency determines the resulting magnitude of erosion and deposition is a question often proposed in geomorphic effectiveness studies. This study investigated that question using digital elevation model differencing to compare and contrast three hyd...
Article
Full-text available
Significant growth in mountain rivers research since 1990 has promoted the concept that canyon-confined mountain rivers have complex topographic features nested from base- to flood-stages due to canyon structure and abundant large bed elements. Nesting means literally structures inside of structures. Mathematically, nesting means that multiple indi...
Method
Full-text available
This tool identifies hydropeaking events from raw time-series flow records, a rapid flow variation induced by the hourly-adjusted electricity market. The novelty of 'HEDA' is to use vector angle instead of the first-order derivative to detect change points which not only largely improves the computing efficiency but also accounts for the rate of ch...
Article
Full-text available
The dynamics of fish stranding have not been academically investigated within the context of physical adjustments to rivers for habitat enhancement purposes. River projects may aim to help fish populations but instead may function as attractive nuisances reducing populations because of unaccounted‐for stranding risk. This study applies a novel algo...
Technical Report
Full-text available
This is the user's manual for River Builder software, which is the world's first procedural generation software capable of generating digital elevation models of a wide variety of river corridor types. The code is open-source and free to use. You can download it from https://github.com/RiverBuilder/RiverBuilder
Article
Full-text available
Hydropeaking, a hydroelectricity generation strategy involving rapid changes to flow releases from dams in response to fluctuations in hourly-adjusted electricity markets has been widely applied due to its economic efficiency. However, these operational practices produce sub-daily flow fluctuations that pose substantial hazards to riverine ecosyste...
Conference Paper
Full-text available
Legal frameworks and global change have significantly increased the number, opportunities and challenges of river engineering interventions in the last decades. In this context, the dynamics of river systems require rapid sustainable planning and implementation of interventions at rivers. Nowadays, technological progress and data science enable eff...
Article
Full-text available
Riffle-pool sequences are fundamental, ubiquitous morphological features of alluvial rivers that are thoroughly studied in general and commonly incorporated into river restoration projects. Most previous investigations on the effect of riffle-pool sequences on hyporheic exchanges focused on solely bed undulation, because that is widely thought to b...
Article
Full-text available
Riverine fish stranding is of significant concern due to its potentially devastating impacts on fish populations already at risk. Because stranding is dependent on a wide range of biotic and abiotic factors, it is difficult to accurately identify and parameterize fish stranding risks for various river topographies, fish species/lifestages and flow...
Poster
Full-text available
https://agu.confex.com/agu/fm20/meetingapp.cgi/Paper/669650
Article
Full-text available
Donwload one of the 50 free eprints here: https://www.tandfonline.com/eprint/C4B3NQVBGVH7HSGSRXTP/full?target=10.1080/24705357.2020.1813057 Interdisciplinary approaches are required to tackle complex environmental issues as freshwater ecosystems face unprecedented pressures globally. The emerging Ecohydraulics field of research should, therefore,...
Conference Paper
River restoration projects with the goals of habitat enhancement and improved flood pro-tection involve ecological, structural, and socio-economic river design. The current best practice virtually assesses the hydro-geo-climatic river landscape with remote sensing techniques and two-dimensional numerical modelling. The resulting data inform the flo...
Chapter
Full-text available
Despite studies showing that dams have significant effects on the sediment dynamics and evolution of a river upstream of a dam, the knowledge on relationships between river topography and sediment transport in the dam’s backwater zone has been poorly applied in reservoir sedimentation management. Therefore, this study evaluated the benefits that to...
Article
Full-text available
Reach‐scale morphological channel classifications are underpinned by the theory that each channel type is related to an assemblage of reach‐ and catchment‐scale hydrologic, topographic, and sediment supply drivers. However, the relative importance of each driver on reach morphology is unclear, as is the possibility that different driver assemblages...
Article
Full-text available
Hydrologic and geomorphic classifications have gained traction in response to the increasing need for basin-wide water resources management. Regardless of the selected classification scheme, an open scientific challenge is how to extend information from limited field sites to classify tens of thousands to millions of channel reaches across a basin....
Article
Full-text available
Seasonal flow transitions between wet and dry conditions are a primary control on river conditions, including biogeochemical processes and aquatic life-history strategies. In regions like California with highly seasonal flow patterns and immense interannual variability, a rigorous approach is needed to accurately identify and quantify seasonal flow...
Article
Full-text available
River design is often conceptually approached aiming at either physical channel stability or ecological functionality. We present a novel concept within an open-source software called River Architect that addresses both these goals and estimates costs. River Architect is flexible for site- and application-specific characteristics, with modules for...
Chapter
Earth is undergoing systemic global ecological collapse caused by human civilization. If the same currency ratio spent on fighting crisis to bearing damages was applied as that evident in addressing crime, then the United States alone would spend $1.1 trillion annually on ecological stewardship. However, would ecosystem scientists, managers, and en...
Article
Full-text available
Microhabitat suitability models are commonly used to estimate salmonid habitat abundance and quality with unknown accuracy or reliability. When tested, the metrics used to evaluate these models are often limited by the methods used to develop them. More generalized bioverification strategies that transcend methodology are therefore needed in ecohyd...
Poster
Full-text available
Global systemic ecological collapse is underway, including in river ecosystems. Traditional river design involving artistically drawn polylines aided by computers cannot meet the needs of producing ecologically and geomorphically sustainable river corridors. Instead, society needs a way to deconstruct known ecosystem mechanisms from functioning riv...
Poster
Full-text available
Fluvial landforms at the 1-10 channel-width scale, termed morphological units (MUs), are omnipresent in alluvial rivers respective of channel pattern, grain-size, and gradient. The presence and spatial structure of these features reflect several levels of grain-fluid, MU-flow, and MU-MU interactions. To date, only limited treatment exists on typolo...
Poster
Full-text available
Numerous hydrodynamic mechanisms result in characteristic river landforms that are integral to the ecohydraulic conditions in streams of all sizes. One mechanism associated with self-regulated riffle and pool formation is flow convergence routing (FCR). Flow convergence routing in alluvial channels produces “wide bars” that are both shallow and wid...
Poster
Full-text available
River channel connectivity plays a vital role in determining the ecologic success of river restoration, habitat enhancement, and management efforts, yet the importance of lateral habitat connectivity is often overlooked. However, if channel connectivity is not adequately addressed, fish stranding and redd dewatering may have devastating impacts on...
Conference Paper
Full-text available
Sustainable concepts of ecologically functional rivers challenge engineers, researchers, and planners. Advanced numerical modeling techniques produce nowadays high-precision terrain maps and spatially explicit hydrodynamic data that aid river design. Because of their complexity, however, ecomorphological processes can only be reproduced to a limite...
Poster
Full-text available
Substrate facies monitoring at high temporal and spatial resolution is critical for the understanding of river geomorphologic and ecohydraulic processes. Recent technological advancements in remote sensing with airborne and ground-based lidar as well as drone imagery are stimulating a new era of substrate mapping and quantification. However, most e...
Poster
Full-text available
Quantification of changes in channel morphology provides a means for monitoring rates and directions of landform change, analyzing fluvial sediment budgets, and identifying processes steering change. These are all relevant to river ecosystem services. Recent remote sensing advances enable inter-annual to decadal monitoring of fluvial topographic ch...
Technical Report
Full-text available
The Yuba River Ecosystem Restoration Feasibility Study (YRERFS) was one of three ecosystem restoration project studies authorized by the U.S. Army Corps of Engineers (USACE) in 2014. Congressional authorization to initiate the study was granted through the Energy and Water Development Appropriations Act, 2014, Division D, P.L. 113-76. After complet...
Chapter
All over the world rivers and the fluvial ecosystem are systemically collapsing in response to cumulative historic and modern anthropogenic impacts. Scientists, engineers, and managers from diverse backgrounds have come together in local to international groups to diagnose problems and implement solutions that restore responsible environmental stew...
Conference Paper
Full-text available
One major component differentiating the landform structure and steering conditions of mountain rivers from lowland gravel-or-sand bedded rivers is the abundance of boulders and bedrock outcrops, collectively referred to as large bed elements (LBEs). LBEs exert a strong influence on channel hydraulics, sediment transport, landforms, and geomorphic p...
Article
Full-text available
Streams draining urban catchments ubiquitously undergo negative physical and ecosystem changes, recognized to be primarily driven by frequent stormwater runoff input. The common management intervention is rehabilitation of channel morphology. Despite engineering design intentions, ecohydraulic benefits of urban channel rehabilitation are largely un...
Article
Full-text available
There has been an increasing practice of creating Earth-like, realistic synthetic landscapes by Earth scientists and computer scientists for a variety of applications. While together these two fields have made significant scientific and social contributions to creating synthetic landscapes, it is presently infeasible to build artificial digital riv...
Article
Small mountainous coastal watersheds are thought to be responsible for transporting disproportionately large volumes of sediment to the global ocean. In comparison with low-relief passive margin rivers, their geologic setting is associated with high rates of sediment production, high peak flows due to uniformity in runoff lag-times, and limited flo...
Article
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Research and engineering efforts are establishing a vast number of stream restoration planning approaches, design testing frameworks, construction techniques, and performance evaluation methods. A primary question arises as to the lifespan of stream restoration features. This study develops a framework to identify relevant parameters, design criter...
Article
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The potential for catchment-scale stormwater control measures (SCMs) to mitigate the impact of stormwater runoff issues and excess stormwater volume is increasingly recognised. There is, however, limited understanding about their potential in reducing in-channel disturbance and improving hydraulic conditions for stream ecosystem benefits. This stud...
Chapter
Ecohydraulics is the study of the mechanisms that explain hierarchically nested aquatic and riparian biotic phenomena. Mechanisms are sequential actions that can be physical, biological, or an interaction between the two. Biotic phenomena consist of individual, population, and community-level conditions, behaviors, and interactions. Hierarchical ne...
Article
Full-text available
Anthropogenic, eco-morphological degradation of lotic waters necessitates laws, directives, and voluntary actions involving stream restoration and habitat enhancement. Research and engineering efforts are establishing a vast number of stream restoration planning approaches, design testing frameworks, construction techniques, and performance evaluat...
Article
Full-text available
Alongshore sediment bypassing rocky headlands remains understudied despite the importance of characterizing littoral processes for erosion abatement, beach management, and climate change adaptation. To address this gap, a numerical model sediment transport study was developed to identify controlling factors and mechanisms for sediment headland bypa...
Poster
Full-text available
AGU Abstract: Riffle-pool, plane bed, and step-pool geomorphic units represent archetypical, instream river forms that exist across a number of hydrologic settings. Given the common existence of these geomorphic units, previous research has identified distinct relationships between channel attributes with these characteristic forms. However, contra...
Poster
Full-text available
In a water-stressed California, how can society meet human needs without jeopardizing the hydro-ecological integrity of rivers and creeks? Answering that critical open question requires a multidisciplinary approach, because the ecological function of a stream is intrinsically linked to its channel geometry and to the magnitude and frequency of its...
Poster
Full-text available
Physical habitat losses for Pacific salmonids in California’s Central Valley motivate stream restoration. Considerable river morphodynamics affect the sustainability of habitat enhancing interventions. In addition, the presence of large dams in many river catchments causes low sediment supply. This study revises existing stream restoration techniqu...
Conference Paper
Full-text available
Independently, there exist analyses based on hydrological, hydraulic, biotic, or geomorphic metrics for testing ecological functionality of fluvial habitats. We propose that these attributes should not be assessed independently, but on a mutual basis such that a location is not considered ecologically functional unless it meets all criteria. This s...
Article
Full-text available
Balancing ecological and human water needs often requires characterizing key aspects of the natural flow regime and then predicting ecological response to flow alterations. Flow metrics are generally relied upon to characterize long-term average statistical properties of the natural flow regime (hydrologic baseline conditions). However, some key as...
Article
Full-text available
Urban streams have almost universally altered physical habitat conditions due to excess stormwater runoff. This includes changes to in‐channel hydraulics and channel morphology. Restoration of in‐channel habitat has two main levers: address the hydrology or channel morphology. Both variables impact in‐stream habitat but understanding the relative r...
Article
Full-text available
Increased public health risk caused by pathogen contamination in streams is a serious issue, and mitigating the risk requires improvement in existing microbial monitoring of streams. To improve understanding of microbial contamination in streams, we monitored in stream water columns and streambed sediment. Two distinct streams and their subwatershe...
Conference Paper
Full-text available
Streams draining urban catchment are almost universally ecologically degraded due to the impact of urbanization. Addressing channel form or flow regime remains two key management components for restoration. Both components impact the stream hydraulic habitat, however, very little is known about the relative influence of the channel and flow alterat...
Conference Paper
Full-text available
It is commonly known that flow regimes of urban streams are altered due to urban development and excess stormwater runoff. This in turn alters the stream hydraulic conditions which can have greater effect on the ecological functioning of the stream ecosystem particularly through bed disturbance (the movement of the streambed materials), limiting re...
Conference Paper
Full-text available
Key Points • Urbanization usually results in degradation of instream habitat • Management efforts often focus on restoring the flow or the channel form • The relative importance of restoring the flow or the channel form is poorly understood • This study uses hydraulic modelling to examine the relative relevance of altered flow and form in addressin...
Article
Full-text available
Improved understanding of pathogen survival in the stream environment is needed to enhance existing predictive models of stream pathogen populations. Further, the increasing use of thermal springs for bathing necessitates additional studies focused on