Adam P Schreiner-Mcgraw

United States Department of Agriculture | USDA · Agricultural Research Service (ARS)

High-resolution characterizations and predictions are a grand challenge for ecohydrology. Recent advances in flight control, robotics and miniaturized sensors using unmanned aerial vehicles (UAVs) provide an unprecedented opportunity for characterizing, monitoring and modeling ecohydrologic systems at high-resolution (,1 m) over a range of scales....

A limited understanding of how extreme weather events affect groundwater hinders our ability to predict climate change impacts in drylands, where channel transmission losses are often the primary recharge mechanism. In this study, we investigate how potential changes to precipitation intensity and temperature will affect the water balance of a typi...

Woody plant encroachment (WPE) into grasslands is a global phenomenon that is associated with land degradation via xerification, which replaces grasses with shrubs and bare soil patches. It remains uncertain how the global processes of WPE and climate change may combine to impact water availability for ecosystems. Using a process-based model constr...

Precipitation is a key input variable in distributed surface water-groundwater models, and its spatial variability is expected to impact watershed hydrologic response via changes in subsurface flow dynamics. Gridded precipitation data sets based on gauge observations, however, are plagued by uncertainty, especially in mountainous terrain where gaug...

To decrease negative environmental impacts associated with row crop agriculture, the conversion of conventional agricultural lands to no-till with cover crops or to restored prairie in the Midwest U.S. has been proposed and has the potential to alter hydrologic behavior. Our understanding of the impacts of this conversion on water and carbon fluxes...

Water returned to the atmosphere as evapotranspiration (ET) is approximately 1.6x greater than global river discharge and has wide-reaching impacts on groundwater and streamflow. In the U.S. Midwest, widespread land conversion from prairie to cropland has altered spatiotemporal patterns of ET, yet there is no consensus on the direction of change in...

Understanding the carbon fluxes and dynamics from a broad range of agricultural systems has the potential to improve our ability to increase carbon sequestration while maintaining crop yields. Short-term, single-location studies have limited applicability, but long-term data from a network of many locations can provide a broader understanding acros...

Accurate simulation of plant water use across agricultural ecosystems is essential for various applications, including precision agriculture, quantifying groundwater recharge, and optimizing irrigation rates. Previous approaches to integrating plant water use data into hydrologic models have relied on evapotranspiration (ET) observations. Recently,...

Mountainous regions act as the water towers of the world by producing streamflow and groundwater recharge, a function that is particularly important in semiarid regions. Quantifying rates of mountain system recharge is difficult, and hydrologic models offer a method to estimate recharge over large scales. These recharge estimates are prone to uncer...

Accurate simulation of plant water use across agricultural ecosystems is essential for various applications, including precision agriculture, quantifying groundwater recharge, and optimizing irrigation rates. Previous approaches to integrating plant water use data into hydrologic models have relied on evapotranspiration (ET) observations. Recently,...

Groundwater is a life-sustaining resource that supplies water to 2 billion people worldwide and is critical for agriculture. Despite the importance of groundwater, understanding of groundwater recovery from meteorological droughts is limited. Here, we utilize daily groundwater observations from unconfined aquifers without active groundwater managem...

Mountainous regions act as the water towers of the world by producing streamflow and groundwater recharge, a function that is particularly important in semiarid regions. Quantifying rates of mountain system recharge is difficult, and hydrologic models offer a method to estimate recharge over large scales. These recharge estimates are prone to uncer...

Woody plant encroachment is a global phenomenon whereby shrubs or trees replace grasses. The hydrological consequences of this ecological shift are of broad interest in ecohydrology, yet little is known of how plant and intercanopy patch dynamics, distributions, and connectivity influence catchment‐scale responses. To address this gap, we establish...

Channel transmission losses alter the streamflow response of arid and semiarid watersheds and promote focused groundwater recharge. This process has been primarily studied in dryland channels draining large areas that are displaced away from hillslope runoff generation. In contrast, small watersheds on arid piedmont slopes allow the investigation o...

The impact of urbanization on water and energy fluxes varies according to the characteristics of the urban patch type. Nevertheless, urban flux observations are limited, particularly in arid climates, given the wide variety of land cover present in cities. To help address this need, a mobile eddy covariance (EC) tower was deployed at three location...

A critical hydrologic process in arid and semiarid regions is the interaction between ephemeral channels and groundwater aquifers. Generally, it has been found that ephemeral channels contribute to groundwater recharge when streamflow infiltrates into the sandy bottoms of channels. This process has traditionally been studied in channels that drain...

Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of the land CO2 sink. However, such model-based analyses are poorly constrained by measured CO2 exchange in open shrublands, which is the most common global land cover type, covering 14% of Earth's surface. Here we evaluate...

Soil moisture dynamics reflect the complex interactions of meteorological conditions with soil, vegetation and terrain properties. In this study, intermediate scale soil moisture estimates from the cosmic-ray sensing (CRS) method are evaluated for two semiarid ecosystems in the southwestern United States: a mesquite savanna at the Santa Rita Experi...

Much information has been in the news in recent years about the use of unmanned aircraft systems (UAS) in border security, antiterrorist operations, and military reconnaissance. Civil applications of UAS are on the rise as well, especially for assisting law enforcement personnel in their normal duties. Although most civil applications of UAS are de...

Soil heterogeneity greatly influences moisture content, making it difficult to accurately determine this parameter in hydrological and ecological studies that require continuous representative measurements at intermediate scales (~1 km). In this context, the COsmic-ray Soil Moisture Observing System (COSMOS) enables us to quantify soil moisture con...

RESUMEN La heterogeneidad del suelo influye ampliamente en el contenido de humedad, dificultando la precisa determinación de este parámetro en estudios con fines hidrológicos y ecológicos que requieren de mediciones continuas y representativas para escalas intermedias (~1 km). En este contexto un sensor de neutrón de rayo cósmico The COsmic-ray Soi...