نتایج جستجو برای: stream slope

تعداد نتایج: 109892  

2005
DAVID M. WALTERS MARY C. FREEMAN DAVID S. LEIGH CATHERINE M. PRINGLE

—We quantified the relationships among urban land cover, fishes, and habitat quality to determine how fish assemblages respond to urbanization and if a habitat index can be used as an indirect measure of urban effects on stream ecosystems. We sampled 30 wadeable streams along an urban gradient (5–37% urban land cover) in the Etowah River basin, Georgia. Fish assemblages, sampled by electrofishi...

2015
Jonathan D. Tonkin Deep Narayan Shah Mathias Kuemmerlen Fengqing Li Qinghua Cai Peter Haase Sonja C. Jähnig

Little work has been done on large-scale patterns of stream insect richness in China. We explored the influence of climatic and catchment-scale factors on stream insect (Ephemeroptera, Plecoptera, Trichoptera; EPT) richness across mid-latitude China. We assessed the predictive ability of climatic, catchment land cover and physical structure variables on genus richness of EPT, both individually ...

2004
David E. Dietrich Avichal Mehra Robert L. Haney Malcolm J. Bowman Yu-Heng Tseng

A two-way-coupled duo grid primitive-equations-based ocean model is used in a 75-year simulation of the North Atlantic Ocean, Caribbean Sea and Gulf of Mexico region between 10◦ N and 73◦ N. All advection and horizontal pressure gradient terms are fourth-order accurate on a semi-Collocated control volume grid. By construction of surface freshwater and heat fluxes, the model multi-year ensemble ...

Journal: :Ecology 2006
Winsor H Lowe Gene E Likens Mark A McPeek Don C Buso

There is growing recognition of the need to incorporate information on movement behavior in landscape-scale studies of dispersal. One way to do this is by using indirect indices of dispersal (e.g., genetic differentiation) to test predictions derived from direct data on movement behavior. Mark-recapture studies documented upstream-biased movement in the salamander Gyrinophilus porphyriticus (Pl...

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...

2009
Patrick D. Broxton Peter A. Troch Steve W. Lyon

[1] In the current empirical study, we provide evidence about how the hydrologic responses of small mountain catchments are related to aspect (slope direction and exposure) at Redondo Peak, located in the Valles Caldera, New Mexico, United States. Specifically, we test the hypothesis that the transit time of water is related to the catchment aspect. Aspect is an easily measurable and transferab...

2001
JEFFREY D. NIEMANN NICOLE M. GASPARINI GREGORY E. TUCKER RAFAEL L. BRAS

Playfair’s law (J. Playfair, illustrations of the Huttonian Theory of the Earth, 1802) requires any two tributaries in a river network to lower at the same rate near their junction. Although this law holds exactly at the junction, it is unclear how well it holds in the vicinity of the junction. This issue has practical importance because Playfair’s law has been used to estimate parameters for d...

Journal: :اکو هیدرولوژی 0
ناصر طهماسبی پور استادیار گروه مرتع و آبخیزداری، دانشکدۀ کشاورزی، دانشگاه لرستان، خرم‏آباد امید رحمتی دانشجوی دکتری علوم و مهندسی آبخیزداری، دانشگاه لرستان، خرم ‏آباد سمیرا قربانی نژاد دانشجوی کارشناسی‏ ارشد مهندسی آبخیزداری، دانشگاه لرستان، خرم ‏آباد

gully erosion constitutes a major problem in natural resources management and soil conservation, which causes severe land degradation in arid and semi-arid areas. therefore, determination of gully prone area and identification of gully conditioning factors can help to managers and decision makers to reduce the hazard of gully erosion. the aim of this study is to predictthe gully erosion suscept...

Journal: :Environmental management 2005
Kelly O Maloney Patrick J Mulholland Jack W Feminella

We conducted a 3-year study designed to examine the relationship between disturbance from military land use and stream physical and organic matter variables within 12 small (<5.5 km2) Southeastern Plains catchments at the Fort Benning Military Installation, Georgia, USA. Primary land-use categories were based on percentages of bare ground and road cover and nonforested land (grasslands, sparse ...

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