A5019257037- Hydrology and Watershed Management Studies
- Cryospheric studies and observations
- Groundwater flow and contamination studies
- Groundwater and Isotope Geochemistry
- Soil and Water Nutrient Dynamics
- Climate change and permafrost
- Flood Risk Assessment and Management
- Hydrology and Sediment Transport Processes
- Plant Water Relations and Carbon Dynamics
- Mercury impact and mitigation studies
- Climate variability and models
- Peatlands and Wetlands Ecology
- Soil erosion and sediment transport
- Hydrological Forecasting Using AI
- Landslides and related hazards
- Reservoir Engineering and Simulation Methods
- Fish Ecology and Management Studies
- Tree-ring climate responses
- Water-Energy-Food Nexus Studies
- Heavy metals in environment
- Toxic Organic Pollutants Impact
- Rangeland and Wildlife Management
- Hydrology and Drought Analysis
- Water resources management and optimization
- Geological Modeling and Analysis
Desert Research Institute
2016-2025
Rocky Mountain Biological Laboratory
2018-2024
Lawrence Berkeley National Laboratory
2020-2023
Choate Rosemary Hall
2023
Rocky Research (United States)
2020
University of Nevada, Reno
2000-2015
Nevada System of Higher Education
2010-2011
Denver Federal Center
2004
United States Army Corps of Engineers
2004
Nevada National Security Site
2004
Core Ideas Development of a 300‐km 2 mountainous headwater testbed began in 2016 the East River. The can be used to explore how watershed changes impact downgradient water availability and quality. System‐of‐system, scale‐adaptive approaches potentially improve dynamics simulation. We have new monitor simulate partitioning system responses. River has been developed as “community” testbed. Extreme weather, fires, land use climate change are significantly reshaping interactions within...
Abstract Groundwater interactions with mountain streams are often simplified in model projections, potentially leading to inaccurate estimates of streamflow response climate change. Here, using a high-resolution, integrated hydrological extending 400 m into the subsurface, we find groundwater an important and stable source historical mountainous watershed Colorado River. In warmer climate, increased forest water use is predicted reduce recharge resulting storage loss. Losses expected be most...
The wetland complex is the functional ecological unit of prairie pothole region (PPR) central North America.Diverse complexes wetlands contribute high spatial and temporal environmental heterogeneity, productivity, biodiversity to these glaciated landscapes.Climatewarming simulations using new model WETLANDSCAPE (WLS) project major reductions in water volume, shortening hydroperiods, less-dynamic vegetation for complexes.The WLS portrays future PPR as a much less resilient ecosystem: western...
Abstract Although important for riverine solute and nutrient fluxes, the connections between biogeochemical processes subsurface hydrology remain poorly characterized. We investigate these couplings in East River, CO, a high‐elevation shale‐dominated catchment Rocky Mountains, using concentration‐discharge (C‐Q) relationships major cations, anions, organic carbon. Dissolved carbon (DOC) displays positive C‐Q relationship with clockwise hysteresis, indicating mobilization depletion of DOC...
Abstract Understanding the sensitivity of groundwater generation to climate in a mountain system is complicated by tight coupling snow dynamics vegetation and topography. To address these feedbacks, we combine light detection ranging (LiDAR)‐derived observations with an integrated hydrologic model quantify spatially temporally distributed water fluxes across varying conditions Colorado River headwater basin. Results indicate that annual flow important stable source stream water. However,...
Abstract Critical zone influences on hydrologic partitioning, subsurface flow paths and reactions along these dictate the timing magnitude of groundwater solute flux to streams. To isolate first‐order controls seasonal streamflow generation within highly heterogeneous, snow‐dominated basins Colorado River, we employ a multivariate statistical approach end‐member mixing analysis using suite daily chemical isotopic observations. Mixing models are developed across 11 nested (0.4 85 km 2 )...
Groundwater dependent ecosystems (GDEs) rely on near-surface groundwater. These systems are receiving more attention with rising air temperature, prolonged drought, and where groundwater pumping captures natural discharge for anthropogenic use. Phreatophyte shrublands, meadows, riparian areas GDEs that provide critical habitat many sensitive species, especially in arid semi-arid environments. While vital ecosystem services function, their long-term (i.e. ~ 30 years) spatial temporal...
Abstract Understanding the partitioning of snow and rain contributing to either catchment streamflow or evapotranspiration (ET) is critical relevance for water management in response climate change. To investigate this partitioning, we use endmember splitting mixing analyses based on stable isotope ( 18 O) data from nine headwater catchments East River, Colorado. Our results show that one third partitions ET 13% snowmelt sustains summer streamflow. Only 8% rainfall contributes streamflow,...
Abstract Quantitative understanding is lacking on how the depth of active groundwater circulation in bedrock affects mountain streamflow response to a multi‐year drought. We use an integrated hydrological model explore sensitivity variety metrics and porosity under plausible extreme drought scenario lasting up 5 years. Endmember versus hydraulic conductivity relationships values for fractured crystalline rock are simulated. With drought, deeper system with higher drainable more effectively...
Abstract To understand how redox processes influence carbon, nitrogen, and iron cycling within the intrameander hyporheic zone, we developed a biotic abiotic reaction network incorporated it into reactive transport simulator PFLOTRAN. Two‐dimensional flow simulations were performed (1) to evaluate transient hydrological conditions control lateral zonation an region of East River in Colorado (2) quantify impact single meander on subsurface exports carbon other geochemical species river. The...
Abstract The selective use of seasonal precipitation by vegetation is critical to understanding the residence time and flow path water in watersheds, yet there are limited datasets test how climate alters these dynamics. Here, we measurements cycle tree ring O for two widespread conifer species Rocky Mountains North America provide a multi‐decadal depiction origins forest use. results show that while stands had dominant preference snowmelt, were multi‐annual periods over last four decades...
Abstract Isotopic information from 81 snowpits was collected over a 5‐year period in large, Colorado watershed. Data spans gradients elevation, aspect, vegetation, and seasonal climate. They are combined with overlapping campaigns for water isotopes precipitation snowmelt, land‐surface model detailed estimates of snowfall climate at sample locations. Snowfall isotopic inputs, describe the majority δ 18 O snowpack variability. Aspect is secondary control, slightly more enriched conditions on...
Abstract. About 80 % of the precipitation at Colorado River's headwaters is snow, and resulting snowmelt-driven hydrograph a crucial water source for about 40 million people. Snowmelt from alpine subalpine snowpack contributes substantially to groundwater recharge river flow. However, dynamics snowmelt progression are not well understood because observations high-elevation difficult due challenging access in complex mountainous terrain as cost labor intensity currently available methods. We...
Abstract Major components of hydrologic and elemental cycles reside underground, where their complex dynamics linkages to surface waters are obscure. We delineated seasonal subsurface flow transport along a hillslope in the Rocky Mountains (USA), precipitation occurs primarily as winter snow drainage discharges into East River, tributary Gunnison River. Hydraulic geochemical measurements down 10 m below ground supported application transmissivity feedback snowmelt describe through three...
Concentration-discharge (C-Q) relationships have been widely used as "hydrochemical tracers" to determine the variability in riverine solute exports across event, seasonal, annual, and decadal time scales. However, these C-Q are limited investigating transport dynamics at individual sampling stations, such that they create an incomplete understanding of behavior upstream or downstream station. Therefore, objective this study is develop, apply assess a differential approach can characterize...
Abstract The North American Monsoon occurs July–September in the central Rocky Mountains bringing significant rainfall to Colorado River headwater basins. This rain may buffer streamflow deficiencies caused by reductions snow accumulation. Using a data‐modeling framework, we explore importance of monsoon generation over historical conditions an alpine basin. Annually, contributes 18 ± 7% water inputs and generates 10 6% streamflow. bulk supports evapotranspiration lower subalpine forests....
Abstract A coupled hydrologic and snowpack stable water isotope model assesses controls on isotopic inputs across a mountainous basin. Annually, the most depleted conditions occur in upper subalpine where snow accumulation is high, rainfall low. Snowmelt evolution over time indicates fractionation processes account for <25% snowmelt enrichment. Meltwater are largely determined by amount, phase mass of precipitation coincident with ablation period. Effect vapor loss from d‐excess balance...
Abstract Land cover change due to drought and insect‐induced tree mortality or altered vegetation succession is one of the many consequences anthropogenic climate change. While hydrologic response land increases in temperature have been explored independently, few studies compared these two impacts a systematic manner. These changes are particularly important snow‐dominated, headwaters systems that provide streamflow for continental river systems. Here we study both warming along three...