United States Department of Agriculture
Rising atmospheric CO2 and resulting warming are expected to impact freshwater resources in the tropics, but few studies have documented how natural stream flow regimes in tropical watersheds will respond to changing rainfall patterns. To address this data gap, we utilized a space-for-time substitution across a naturally occurring and highly...
Changes in size of annual and seasonal yields and instantaneous peak flows were determined on three small, experimental watersheds following three silvicultural methods of timber harvest. Changes are related to changes in forest hydrologic system.
Prescribed fire, a practice applied annually to about 106 hectares of forests in the southeastern United States, had limited effects on soils, nutrient cycling, and hydrologic systems of a coastal plain pine forest. Hydrologic fluxes of nitrogen, phosphorus, sulfur, and basic cations, from burned pine litter to ground and stream waters, are not likely to have...
The low-gradient, forested wetland landscape of the southeastern United States’ Coastal Plain represents an important eco-hydrologic system, yet there is a very little information available on the region’s ecological, hydrological and biogeochemical processes. Long-term hydrologic monitoring can provide the information needed to understand basic hydrologic processes...
One of the biggest challenges society faces in this new century is figuring out how to satisfy the water demands of 8 billion people while at the same time protecting the aquatic ecosystems and ecological services that humans and all species depend upon. Since 1950, water demands worldwide have more than tripled, while the scale of our dams and reservoirs, river...
Forest, woodland, and grassland watersheds throughout the world are major sources of high quality water for human use because of the nature of these soils to infiltrate, store, and transmit most precipitation instead of quickly routing it to surface runoff. This characteristic of these wildland soils is due to normally high infiltration rates, porosities, and hydraulic...
Abstract - In 1987, a 0.83-ha zero-order swale was instrumented with 58 pierometers and 25 tensiometers along several hillslope transects. Through 1993, soil moisture conditions were measured by pressure transducers connected to a digital data logger recording at 15-minute intervals. In August 1989, the 100-year-old second-growth forest in the swale was felled. Logs...
Riverine organic matter supports of the order of one-fifth of estuarine metabolism. Coastal ecosystems are therefore sensitive to alteration of both the quantity and lability of terrigenous dissolved organic matter (DOM) delivered by rivers. Here we characterize streamwater DOM from 11 coastal watersheds on the Gulf of Alaska that vary widely in glacier coverage. In...
The importance of forests in providing reliable sources of clean water cannot be underestimated. Therefore, there is a pressing need to understand how hydrologic systems function in forested ecosystems, in response to a variety of traditional and novel stressors and environments. Long-term watershed research on Experimental Forests and Ranges (EFRs) of the Forest...
Wildfire is an important disturbance affecting hydrological processes through alteration of vegetation cover and soil characteristics. The effects of fire on hydrological systems at the catchment scale are not well known, largely because site specific data from both before and after wildfire are rare. In this study a modelling approach was employed for change detection...
The use of smart tracers to study hydrologic systems is becoming more widespread. Smart tracers are compounds that irreversibly react in the presence of a process or condition under investigation. Resazurin (Raz) is a smart tracer that undergoes an irreversible reduction to resorufin (Rru) in the presence of cellular metabolic activity. We quantified the relationship...
Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at...
The history of watershed research in the Interior Highlands can be divided into four periods: Initial Start and Stumble (1930s–1950s), Reestablishment and Renewal (1960–1980), Partnerships and Expansion (1980–1990), and New Scales and Paths (1990–present). While each of these periods was marked by different societal concerns and scientific questions, experimental...
Within the Deschutes River basin of central Oregon, the geology, hydrology, and physiography influence geomorphic and ecologic processes at a variety of temporal and spatial scales. Hydrologic and physiographic characteristics of the basin are related to underlying geologic materials. In the southwestern part of the basin, Quaternary volcanism and tectonism has created...
Imparting knowledge of the physical processes of a system to a model and determining a set of parameter values for a hydrologic or water quality model application (i.e., parameterization) are important and difficult tasks. An exponential...
In this chapter, we review current scientific understanding and hypotheses at seven system delineations that build up from the level of a ‘tree’ interacting with water, to that of a social-ecological system at the scale of landscapes. A system delineation separates internal entities that interact dynamically from external entities that may have a one-way influence but...
At the beginning of the 21st century more than 50% of the world’s population lived in cities. By 2050, this percentage will exceed 60%, with the majority of growth occurring in Asia and Africa. As of 2020 there are 31 megacities, cities whose population exceeds 10 million, and 987 smaller cities whose populations are greater than 500 thousand but less than 5 million in...
The North Cascadia Adaptation Partnership (NCAP) is a science-management partnership consisting of the U.S. Department of Agriculture Forest Service Mount Baker-Snoqualmie and Okanogan-Wenatchee National Forests and Pacific Northwest Research Station; North Cascades National Park Complex; Mount Rainier National Park; and University of Washington Climate Impacts Group....