Research

Hydrologic processes are typically measured with sensors that offer spatially- and, in some cases, temporally- discrete data. For example, the United States Geological Survey streamflow network is one of the largest and most comprehensive worldwide, however, it covers less than 1% of the country’s streams and rivers and flow monitoring is biased toward larger, perennial streams and rivers . The growth of Distributed Acoustic Sensing (DAS) with fiber optic cables in the geosciences over the last decade offers a unique and timely opportunity to evaluate the potential of DAS to monitor diverse hydrologic processes and to develop next-generation methods and algorithms to quantify hydrologic variables continuously and more rapidly than currently possible. The long-term goal is to develop the necessary tools and guidelines that will enable agencies such as the USGS to have continuous and reliable Discrete Acoustic Sensing measurements of hydrologic processes (fluvial, groundwater, groundwater/surface water exchange), augmenting more traditional monitoring methods. As an initial step to achieve that goal, the main objective of this project is to evaluate the potential of Distributed Acoustic Sensing (DAS) to quantify different hydrologic processes in the surface and the subsurface through field deployments and laboratory experiments.

Collaborators: Negar Soltani, Tieyuan Zhu, Martin Briggs

Quantifying streamflow is vital for water resource management, habitat monitoring, and emergency response. Streamflow measurements typically use direct or indirect approaches that depend on site and flow conditions. Extreme events and/or flashy systems (remote, urban) are difficult to measure because of the need for timely access to the sites, sensor maintenance issues, and safety concerns. Image-based techniques can be relatively low cost and have the advantage of not needing to be in the water to conduct the measurements. Nevertheless, they may face limitations depending on sunlight conditions, surface reflections, presence of fog, rain and camera angle or field of view. Under such conditions, flow field reconstruction from image-based velocimetry may become sparse or have lower quality.  This project will enhance image-based streamflow measurements (STIV and LSPIV) by combining proven machine learning approaches with image-based velocimetry methods to improve the reliability of these measurements and make the technique accessible to users worldwide.

Collaborators: Frank Engel, Xiaofeng Liu, Alejandro Tenorio

                                                                                                                                                                                                                                                                                                                                                                                Funding: USGS

Ten percent of our planet is covered by ice, and eleven percent of it is underlain by permafrost (i.e., ground that is frozen year-round). Thawing induced by increasing temperatures makes these regions extremely vulnerable to large landscape and ecosystem changes and will affect the health and wellbeing of people that inhabit and rely on them. Moreover, key infrastructure, including key U.S. energy infrastructure, built in these regions is at risk of being destroyed. At the root of these forthcoming landscape changes lie small-scale erosive processes. As ice melts and permafrost thaws, they promote the movement of sediment grains that would otherwise be fixed in place. To provide resilient solutions to the challenges imposed by climate-change in cold regions, we desperately need to quantify those small-scale erosive processes driving most of the large-scale landscape changes. 

This project has been featured in the IEE website: Cold Regions Research at PSU and in the Growing Impact podcast: Investigating Thawing Permafrost

Collaborators: Anastasia Piliouras, Talley Fisher, Daryl Branford, Elena Halmi, Navneet Singh

                                                                                                                                                                                                                                                                                                  Funding: Institute of Energy and the Environment

Erosion is nature’s most successful artist. Its artwork is found everywhere on our planet and across many extra-terrestrial environments. It sculpts a full range of landscapes, including urban desire paths, created by human and animal footfall; meandering river canyons, created by water flows; and coastal cliffs worn away by repeated wave action. Erosion operates at many scales, often creating repeating patterns, which can be produced through different processes such as: erosion and deposition of sediment (e.g. Amazon River), mechanical wear and abrasion of bedrock (e.g. Colorado River), dissolution (e.g. meandering channels over limestone) and melting (meltwater channels over icecaps or glaciers). 

This cross-disciplinary project at the science-arts interface will allow me to move beyond communicating an idea (scientific outputs) to make people experience it (artistic outputs). 

This project has been featured in The Leverhulme Trust website: Grants in Focus

 Funding: The Leverhulme Trust

Rivers develop meandering patterns over many different media and across many different scales. One particular case is that of meltwater meandering channels, which form and evolve over glaciers and other ice surfaces. These channels show remarkable similarities with meandering channels in other media such as alluvium and bedrock. 

I conducted laboratory experiments on meltwater meandering channels at two scales, i.e. width ~1cm and ~1mm,  to quantify their planform morphologies and similarity with meandering channels in other media. The results, which are being prepared for publication, answer the following questions: 

1. How do  meltwater meandering channels on ice form and evolve? 

2. How do their planform morphologies compare to those of alluvial meandering rivers?

3. How do their lateral migration and vertical incision signatures compare to those in other environments?

Results from this study have been published in Earth Surface Dynamics.  Paper: Fernández and Parker (2021)

 Funding: NSF and The Leverhulme Trust

Our coasts, estuaries, and low-land river environments are some of the most sensitive systems to environmental change. In order to manage these systems, and adapt to future changes, we desperately need to be able to predict how they will alter under various scenarios. However, our knowledge of these environments is not yet enough to predict, with confidence, far into the future. One of the main reasons our models and geological interpretations of coastal environments are not yet good enough, is because these models have formulations that are based on assumptions that these systems are composed of only non-cohesive sands. However, mud is the most common sediment on Earth and many of these systems are actually dominated by biologically-active muds and complex sediment mixtures. This project will provide answers to the following questions:

• What is the influence of sediment size and mineralogical composition on coastal morphology in the nearby coastal areas of the Amazon, Tocantins and Parnaiba Rivers in Brazil?

• What is the role of climate, riverine sediment supply, ocean currents and geology in the progression of dune fields into the towns and villages in Parnaiba, Brazil?  What are the risks to local communities and mangrove systems associated with dune migration?

Collaborators: Marco Martins, Lívia Carrera, Daniel Parsons. 

Project-Funding: ERC-Confap-CNPq 

Sediment beds with mixtures of cohesive and non-cohesive material exhibit different behaviors than those of purely non-cohesive sediment under similar hydrodynamic forcings. I am currently running experiments that will provide answers to the following questions:

• How does a mixed-sediment substrate, compared with a pure sand bed, affect the first appearance of combined flow induced ripples, and the bedform development rate?

• What is the rate of winnowing under different hydrodynamic conditions (e.g., different current velocity) and how does it influence the development of ripples?

• Does increasing bed clay fraction affect ripple geometry? 

• How much clay is pumped into clean-sand areas, after it has been winnowed out from clay-rich areas in the experimental reach? 

Experiments are being conducted in the Total Environment Simulator (TES), University of Hull. 

Collaborators: Xuxu Wu, Ellen Pollard, Elena Bastianon, Anne Baar, Jonathan Malarkey, Jaco Baas, Andrew Manning, Daniel Parsons. 

Project-Funding: GEOSTICK - ERC

Harbor Bathymetric Surveys: The volume of sediment deposited inside the harbor increases rapidly between March and July. 

I conducted research with Japanese visitors and colleagues from the University of Illinois looking at the morphologies of cyclic steps formed by pulsed turbidity currents. The goal of the experiment was to understand how the duration of the pulses affects the characteristics of the cyclic steps and the deposits. 

Researchers involved:

Kazunori Fujita, Isamu Mori, Miwa Yokokawa (Osaka Institute of Technology); Roberto Fernández, Matt Czapiga, John Berens, Jeffrey Kwang, Kensuke Naito, Gary Parker(Univ. of Illinois); Norihiro Izumi (Hokkaido Univ.); Hajime Naruse (Kyoto Univ.)

Cyclic Steps: Top panel shows turbidity current over deposit created after 20 pulses. The run shown had turbidity current pulses of 20 seconds. Bottom panel shows deposit after 40 pulses. Velocities were measured with ADVs and grain size distributions of the material analyzed with a Mastersizer.