Publications

Many subsurface processes involve transitions in granular material states, from arrested to creeping to flowing. Experiments and frameworks for idealized systems reveal that granular fabrics develop during shearing, co-evolve with applied stress, and govern such transitions. We use microtomography to test whether fabrics at two San Andreas fault sites reflect slip history and whether...

Monitoring cyanobacteria and other nuisance phytoplankton in the Hudson River is of great interest given its societal and ecological importance. Satellite remote sensing provides a cost-effective method to monitor chlorophyll-a (chl-a), a common proxy for algal biomass; however, the dynamic nature of rivers complicates approaches traditionally applied to lakes and oceans. During 2021...

The Iowa River alluvial aquifer is an important source of water on the Meskwaki Settlement in Tama County, Iowa, which is land owned by the Sac & Fox Tribe of the Mississippi in Iowa (commonly known as the Meskwaki Nation). The U.S. Geological Survey constructed a groundwater flow model, including a conceptual and numerical model, of the Iowa River alluvial aquifer and underlying...

Integration of agroecosystems and other working landscapes with protected lands and waters is critical to the conservation of Earth's biodiversity. Rice agroecosystems support many species by providing aquatic habitat where natural wetlands have been altered or drained. In regions with long dry seasons, rice fields and associated irrigation canals provide essential habitat for wetland...

Objective White Catfish Ameiurus catus has been introduced to coastal watersheds across the United States. In the Penobscot River, Maine, this species has become increasingly common in upstream habitats that have been made accessible by recent dam removals. We characterized the movements of White Catfish to understand the temporal variation in their movement patterns and contextualize...

Sediment bulk density (ρ-dry) and particle size are two important parameters for predicting sediment bed erosion. ρ-dry, however, is difficult to measure accurately. The units of ρdry have not been consistently reported in the literature, leading to confusion, particularly in the calculation of sediment budgets that typically require integrating mass-based and volumetric components...

The Lee Acres Landfill and Giant Bloomfield Refinery are adjacent properties near the City of Farmington, New Mexico, each having undergone monitoring and remediation related to historical site activities. At the landfill, site cleanup has included the installation of a capillary barrier over former liquid waste lagoons and periodic monitoring of groundwater elevations and groundwater...

Quantifying sea turtle nesting behavior is essential for recovery planning and evaluating management actions. Traditional monitoring approaches, based on nest counts from beach surveys, can misclassify non-nesting emergences, obscure true fecundity, and underestimate clutch frequency, metrics that directly influence population models and regulatory decisions. Here, we demonstrate that...

We investigate the growth of a passive lava lake in Halemaʻumaʻu crater during the December 2020 to May 2021 eruption of Kīlauea volcano, Hawaii. Fed by vents above their surfaces, the formation of passive lava lakes in topographic lows is an important process in the growth of basaltic volcanoes. We captured visible and thermal images during 17 helicopter overflights and applied...

Regulatory mandates to improve water quality and stream health have driven substantial investment in stream restoration. Most projects aim to improve channel-floodplain connectivity, reduce sediment erosion, and enhance habitat for aquatic organisms, yet few include adequate pre- and post-restoration monitoring to assess outcomes. Since 2007, Fairfax County, Virginia, and the U.S...

The National Atmospheric Deposition Program (NADP) collects atmospheric data to monitor air pollution effects on the quality of United States water supplies and ecosystems. The NADP requires consistent data collection at fixed locations and is governed by a committee with participation by many Federal and State agencies, universities, Tribes, and private companies. NADP conducts a spring...

Understanding the distribution of grizzly bear populations in the lower-48 states, is important for their conservation and management, and for public safety. Previously, our research teams working in grizzly bear ecosystems in the lower-48 states used varying methods to estimate distribution of grizzly bear populations. In the Greater Yellowstone Ecosystem (GYE) and Northern Continental...