A5078840616- Hydrology and Watershed Management Studies
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Climate variability and models
- Soil erosion and sediment transport
- Flood Risk Assessment and Management
- Hydrology and Sediment Transport Processes
- Climate change and permafrost
- Fish Ecology and Management Studies
- Soil and Water Nutrient Dynamics
- Water resources management and optimization
- Hydrology and Drought Analysis
- Soil and Unsaturated Flow
- Fire effects on ecosystems
- Tree-ring climate responses
- Groundwater flow and contamination studies
- Forest Management and Policy
- Groundwater and Isotope Geochemistry
- Hydrological Forecasting Using AI
- Irrigation Practices and Water Management
- Soil Moisture and Remote Sensing
- Meteorological Phenomena and Simulations
- Archaeology and Natural History
- Soil Geostatistics and Mapping
- Species Distribution and Climate Change
University of California, Merced
2016-2025
University of California Division of Agriculture and Natural Resources
2019-2025
University of California, Davis
2019-2025
Pacific Southwest Research Station
2016-2021
US Forest Service
2015-2019
Oregon State University
2011-2017
University of Hawaiʻi at Mānoa
2009-2012
Sherman Hospital
2009
Abstract Earth System Models (ESMs) are essential tools for understanding and predicting global change, but they cannot explicitly resolve hillslope‐scale terrain structures that fundamentally organize water, energy, biogeochemical stores fluxes at subgrid scales. Here we bring together hydrologists, Critical Zone scientists, ESM developers, to explore how hillslope may modulate grid‐level fluxes. In contrast the one‐dimensional (1‐D), 2‐ 3‐m deep, free‐draining soil hydrology in most land...
Abstract California is experiencing one of the worst droughts on record. We use a hydrological model and risk assessment framework to understand influence temperature water year (WY) 2014 drought in examine probability that this would have been less severe if temperatures resembled historical climatology. Our results indicate played an important role exacerbating WY severity. found 1916–2012 climatology, there at least 86% chance winter snow equivalent spring‐summer soil moisture runoff...
Worldwide, lack of data on stream temperature has motivated the use regression-based statistical models to predict temperatures based more widely available air temperatures. Such have been applied project responses under climate change, but performance these not fully evaluated. To address this knowledge gap, we examined two used linear and nonlinear regression that We evaluated model temporal stability parameters in a suite regulated unregulated streams with 11–44 years data. Although such...
Enhanced understanding of subsurface water storage will improve prediction future impacts climate change, including drought, forest mortality, wildland fire, and strained security. Previous research has examined the importance plant‐accessible in soil, but upland landscapes within Mediterranean climates, soil often accounts for only a fraction storage. We draw insights from previous case study Southern Sierra Critical Zone Observatory to define attributes storage; review observed patterns...
Mountain runoff ultimately reflects the difference between precipitation (P) and evapotranspiration (ET), as modulated by biogeophysical mechanisms that intensify or alleviate drought impacts. These modulating are seldom measured not fully understood. The impact of warm 2012-15 California on heavily instrumented Kings River basin provides an extraordinary opportunity to enumerate four controlled mountain hydrology. Two intensified impact: (i) evaporative processes have first access local...
Abstract One of the principal questions in hydrology is how and when water leaves critical zone storage as either stream flow or evapotranspiration. We investigated subsurface selection Southern Sierra Critical Zone Observatory (California, USA) within age‐ranked framework, constrained by a novel combination cosmogenic radioactive stable isotopes: tritium, sodium‐22, sulfur‐35, oxygen‐18. found significant positive correlation between tritium rate sulfur‐35 rate, indicating that age...
Abstract A key challenge for resource and land managers is predicting the consequences of climate warming on streamflow water resources. During last century in western United States, significant reductions snowpack earlier snowmelt have led to an increase fraction annual during winter a decline summer. Previous work has identified elevation as it relates dynamics primary control sensitivity warming. But along with changes timing accumulation melt, summer streamflows are also sensitive...
Record low snowpack conditions were observed at Snow Telemetry stations in the Cascades Mountains, USA during winters of 2014 and 2015. We tested hypothesis that these are analogs for temperature sensitivity snowpacks. In Oregon Cascades, 2015 winter air anomalies approximately +2 °C +4 above climatological mean. used a spatially distributed energy balance model to simulate multiple metrics warming compared our modeled sensitivities values found each +1 warming, basin-mean peak snow water...
ABSTRACT In the western United States, climate warming poses a unique threat to water and snow hydrology because much of snowpack accumulates at temperatures near 0 °C. As continues warm, region's precipitation is expected switch from rain, causing flashier hydrographs, earlier inflow reservoirs, reduced spring summer snowpack. This study investigates historical variability in proportion ( S f ) maps areas States that have demonstrated higher sensitivity past. Projected changes under 1.1,...
In the semi-arid environment of Blue Mountains, Oregon (USA), water is a critical resource for both ecosystems and human uses will be affected by climate change in near- long-term. Warmer temperatures reduce snowpack snow-dominated watersheds transition to mixed rain snow, while snow dominated shift towards dominated. This result high flows occurring more commonly late autumn winter rather than spring, lower low summer, phenomena that may already Pacific Northwest. Higher peak are expected...
Abstract Wetlands in arid landscapes provide critical habitat for millions of migratory waterbirds across the world and throughout their annual cycle. The scope scale understanding avian use these wetlands conjunction with changes climate are daunting yet to address lest we lose continent-wide pathways. Here, assess waterbird North America’s Pacific Flyway Great Basin by examining water availability trends over past 100 years. We found recent (1980–2015) warming has significantly reduced...
Core Ideas Water quality and stream flow have temporal spatial trends in response to variable climate. Our work reveals how Sierra Nevada forests responded recovered from multiyear drought. Regolith thickness reveal water storage capacity differences with elevation. Monitoring shows deep‐water changes via plant utilization or capillary during Sensor networks within the Southern Critical Zone Observatory (SSCZO) Kings River Experimental Watersheds (KREW) document cycle spanning west slope of...
Abstract The impact of potential future climate change scenarios on streamflow and evapotranspiration (ET) in a mountainous Hawaii watershed was studied using the distributed hydrology soil vegetation model (DHSVM). hydrologic response simulated for 43 years different levels atmospheric CO 2 (330, 550, 710 970 ppm), temperature (+1.1 + 6.4 °C) precipitation (±5%, ±10% ±20%) basis Intergovernmental Panel Climate Change (IPCC) AR4 projections under current, B1, A1B1 A1F1 emission scenarios....
Along the western margin of North America, winter expression Pacific High (NPH) strongly influences interannual variability in coastal upwelling, storm track position, precipitation, and river discharge. Coherence among these factors induces covariance physical biological processes across adjacent marine terrestrial ecosystems. Here, we show that over past century degree spatial extent this (synchrony) has substantially increased, is coincident with rising variance NPH. Furthermore,...
Abstract Despite a multitude of small catchment studies, we lack deep understanding how variations in critical zone architecture lead to hydrologic states and fluxes. This study characterizes dynamics 15 catchments the U.S. Critical Zone Observatory (CZO) network where hypothesized that our subsurface structure would illuminate patterns partitioning. The CZOs collect data sets characterize physical, chemical, biological subsurface, while also monitoring fluxes such as streamflow,...
Abstract The water balance is an essential tool for hydrologic studies and quantifying water‐balance components the focus of many research catchments. A fundamental question remains regarding appropriateness closure assumptions when not all are available. In this study, we leverage in‐situ measurements fluxes storage from Southern Sierra Critical Zone Observatory (SSCZO) Kings River Experimental Watersheds (KREW) to investigate annual errors across large (1016–5389 km 2 ) river basins small...
ABSTRACT Headwater watersheds and forests play a crucial role in ensuring water security for the western United States. Reducing forest biomass from current overgrown can mitigate severity impact of wildfires offer additional competing ecohydrological benefits. A reduction canopy interception transpiration following treatments lead to an increase available remaining trees runoff. However, management on balance be highly variable due differences climate, topography, location vegetation. In...
Montane watersheds of California’s Sierra Nevada are critical to sustaining local water security and economic wellbeing. However, decades fire suppression have led overgrown forests that highly vulnerable drought wildfire risks. Moreover, climate change is further compounding the negative impacts increased forest density. Land managers implementing active management restore source build resilience. In this study, we investigated individual impact thinning warming on watershed...
The Tulare Lake Basin (TLB) of California, a vital agricultural hub that covers the southern part Sierra Nevada and Central Valley, is experiencing severe water scarcity due to climate change, rising demand, extensive groundwater depletion. This study leverages an integrated hydrological model quantify Surface Water-Groundwater (SW-GW) interactions in TLB. We focus on understanding seasonal balance trends, variability recharge, impact snowmelt storage. integrated SWAT+gwflow was...
Abstract In a Mediterranean climate where much of the precipitation falls during winter, snowpacks serve as primary source dry season runoff. Increased warming has led to significant changes in hydrology western United States. An important question this context is how best manage forested catchments for water and other ecosystem services? Answering basic requires detailed understanding hydrologic functioning these catchments. Here, we depict differences response 10 Size study ranges from 50...
Manure amendments affect several soil physical and hydrologic properties. The objectives of this study were to evaluate the effect (i) manure amendment rates (0, 168, 336, 672 kg total N ha−1), levels (one-time application, two-time application), types (chicken [CM], dairy [DM], swine [SM]) on bulk density (ρb), porosity (θt), saturated hydraulic conductivity (Ksat) a highly weathered tropical (Waialua gravely clay variant, isohyperthermic Pachic Haplustolls) (ii) measuring instruments...