نتایج جستجو برای: representative watersheds

تعداد نتایج: 92866  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Robert I McDonald Katherine F Weber Julie Padowski Tim Boucher Daniel Shemie

Urban water systems are impacted by land use within their source watersheds, as it affects raw water quality and thus the costs of water treatment. However, global estimates of the effect of land cover change on urban water-treatment costs have been hampered by a lack of global information on urban source watersheds. Here, we use a unique map of the urban source watersheds for 309 large cities ...

Journal: :Environmental management 2007
Kimberly M Mattson Paul L Angermeier

Conservation planning aims to protect biodiversity by sustainng the natural physical, chemical, and biological processes within representative ecosystems. Often data to measure these components are inadequate or unavailable. The impact of human activities on ecosystem processes complicates integrity assessments and might alter ecosystem organization at multiple spatial scales. Freshwater conser...

2012
C. Oliver L. M. Risse D. Radcliffe M. Habteselassie J. Clarke Georgia

On-site wastewater treatment systems (OWTSs) are widely used in the Southeastern United States for municipal wastewater treatment. As urban and suburban populations increase, the use of OWTSs is expected to further increase. This region heavily depends on surface waters for its water supply, therefore, the impact of OWTSs on surface water quality and quantity must be investigated. Conventional ...

2010
Anthony J. Ranalli Donald L. Macalady

0022-1694/$ see front matter Published by Elsevier doi:10.1016/j.jhydrol.2010.05.045 * Corresponding author. Tel.: +1 303 236 4882x313 E-mail address: [email protected] (A.J. Ranalli). We reviewed published studies from primarily glaciated regions in the United States, Canada, and Europe of the (1) transport of nitrate from terrestrial ecosystems to aquatic ecosystems, (2) attenuation of nitrat...

Journal: :Environmental management 2009
Jeffrey T Maxted Matthew W Diebel M Jake Vander Zanden

Agricultural non-point source (NPS) pollution poses a severe threat to water quality and aquatic ecosystems. In response, tremendous efforts have been directed toward reducing these pollution inputs by implementing agricultural conservation practices. Although conservation practices reduce pollution inputs from individual fields, scaling pollution control benefits up to the watershed level (i.e...

Journal: :Journal of environmental quality 2016
Mark B David Corey A Mitchell Lowell E Gentry Ronald K Salemme

Chloride is a relatively unreactive plant nutrient that has long been used as a biogeochemical tracer but also can be a pollutant causing aquatic biology impacts when concentrations are high, typically from rock salt applications used for deicing roads. Chloride inputs to watersheds are most often from atmospheric deposition, road salt, or agricultural fertilizer, although studies on agricultur...

1999
Michael McAllister Jack Snoeyink

The Terrain Resources Inventory Mapping (TRIM) data standard in BC, Canada, includes speci cations for river data and elevation data that are typically met by interpretation of stereo orthophotos. It does not specify that breaklines for watersheds be interpreted from the photos, thus we must extract them from the data. We seek a system of watersheds that, while not exact due to errors in the da...

Journal: :Journal of environmental quality 2004
R D Harmel H A Torbert B E Haggard R Haney M Dozier

When improperly managed, land application of animal manures can harm the environment; however, limited watershed-scale runoff water quality data are available to research and address this issue. The water quality impacts of conversion to poultry litter fertilization on cultivated and pasture watersheds in the Texas Blackland Prairie were evaluated in this three-year study. Edge-of-field N and P...

2016
Quenton M. Tuckett Peter Koetsier

Wildfire is an important and prevalent agent of disturbance in vegetated landscapes across much of the Earth’s surface, including forested watersheds in the arid western USA. Between 1992 and 2003, >40% of the watersheds in the upper reaches of the Boise River watershed in central Idaho burned. The purpose of our study was to investigate the legacy effects of wildfire on stream ecosystems by an...

2005
X. Zhou N. Persaud

Fractal scaling behavior of long-term records of daily runoff time series in 31 sub-watersheds covering a wide range of size were examined using the shifted box-counting method and Hurst rescaled range (R/S) analysis. These subwatersheds were associated with four agricultural watersheds of different climate and topography. The results showed that the records of daily runoff rate exhibited scale...

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