نتایج جستجو برای: representative watersheds

تعداد نتایج: 92866  

Journal: :Journal of environmental quality 2014
Ayron M Strauch Richard A Mackenzie Gregory L Bruland Ralph Tingley Christian P Giardina

Potential shifts in rainfall driven by climate change are anticipated to affect watershed processes (e.g., soil moisture, runoff, stream flow), yet few model systems exist in the tropics to test hypotheses about how these processes may respond to these shifts. We used a sequence of nine watersheds on Hawaii Island spanning 3000 mm (7500-4500 mm) of mean annual rainfall (MAR) to investigate the ...

Journal: :Environmental management 2007
Ellen Wohl David Cooper LeRoy Poff Frank Rahel Dennis Staley David Winters

This paper presents a hierarchical analysis of stream ecosystem distribution and sensitivity to natural and anthropogenic disturbances for the Bighorn National Forest, Wyoming. We designated stream gradient, flow regime, and lithology as environmental parameters that would result in the most robust, readily applied, and parsimonious description of physical and chemical characteristics of indivi...

2009
J. X. Zhang J. Q. Wu K. Chang W. J. Elliot S. Dun

The recent modification of the Water Erosion Prediction Project (WEPP) model has improved its applicability to hydrology and erosion modeling in forest watersheds. To generate reliable topographic and hydrologic inputs for the WEPP model, carefully selecting digital elevation models (DEMs) with appropriate resolution and accuracy is essential because topography is a major factor controlling wat...

2011
Wen Zhang Yuichi S. Hayakawa Takashi Oguchi

“Danxia landform” is a landform type originally defined in China, characterized by red-colored sandstones and steep cliffs, and developed through long-term erosion. In recent years, Danxia landforms have been receiving international attention, and six examples in China became a UNESCO World Natural Heritage in 2010. However, morphometric studies of Danxia landforms in China have been very limit...

Journal: :Journal of environmental quality 2011
A M Lemke K G Kirkham T T Lindenbaum M E Herbert T H Tear W L Perry J R Herkert

Best management practices (BMPs) are widely promoted in agricultural watersheds as a means of improving water quality and ameliorating altered hydrology. We used a paired watershed approach to evaluate whether focused outreach could increase BMP implementation rates and whether BMPs could induce watershed-scale (4000 ha) changes in nutrients, suspended sediment concentrations, or hydrology in a...

2007
Sean M. Eagan Carolyn T. Hunsaker Christopher R. Dolanc Marie E. Lynch Chad R. Johnson

The Kings River Experimental Watershed (KREW) is now in its third year of data collection on eight small perennial watersheds. We are collecting meteorology, stream discharge, sediment load, water chemistry, shallow soil water chemistry, vegetation, macro-invertebrate, stream microclimate, and air quality data. This paper primarily examines discharge and sediment data from six watersheds betwee...

2013
Robert M. Northington Jackson R. Webster Ernest F. Benfield Beth M. Cheever Barbara R. Niederlehner

Forested ecosystems in the southeastern United States are currently undergoing an invasion by the hemlock woolly adelgid (HWA). Previous studies in this area have shown changes to forest structure, decreases in canopy cover, increases in organic matter, and changes to nutrient cycling on the forest floor and soil. Here, we were interested in how the effects of canopy loss and nutrient leakage f...

Journal: :Water science and technology : a journal of the International Association on Water Pollution Research 2011
M D Tomer M A Locke

The Conservation Effects Assessment Project was established to quantify water quality benefits of conservation practices supported by the U.S. Department of Agriculture (USDA). In 2004, watershed assessment studies were begun in fourteen agricultural watersheds with varying cropping systems, landscapes, climate, and water quality concerns. This paper reviews USDA Agricultural Research Service '...

2007
AS IIO P. H. Gowda D. J. Mulla

In this study, a set of nitrogen reduction strategies were modeled to evaluate the feasibility of improving water quality to meet total maximum daily loads (TMDLs) in two agricultural watersheds. For this purpose, a spatial-process model was calibrated and used to predict monthly nitrate losses (1994-96) from Sand and Bevens Creek watersheds located in south-central Minnesota. Statistical compa...

2012
Pei-Te Chiueh Wei-Ting Shang Shang-Lien Lo

Watersheds are recognized as the most effective management unit for the protection of water resources. For surface water supplies that use water from upstream watersheds, evaluating threats to water quality and implementing a watershed management plan are crucial for the maintenance of drinking water safe for humans. The aim of this article is to establish a risk assessment model that provides ...

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