نتایج جستجو برای: drainage basin

تعداد نتایج: 96262  

Journal: :Environmental management 2002
Lance R Williams Christopher M Taylor Melvin L Warren J Alan Clingenpeel

Using Basin Area Stream Survey (BASS) data from the United States Forest Service, we evaluated how timber harvesting influenced patterns of variation in physical stream features and regional fish and macroinvertebrate assemblages. Data were collected for three years (1990-1992) from six hydrologically variable streams in the Ouachita Mountains, Arkansas, USA that were paired by management regim...

Journal: :تحقیقات جغرافیایی 0
معصومه روستائی دانشگاه گلستان مریم آق آتابای دانشگاه گلستان

current research in order to identify neo tectonic activity of the ziyarat basin has been made on the northern slopes of the eastern alborz in south-gorgan and using the index of morpho tectonic and tectonic evidence in the area. in this regard, the 6 morphological parameters were calculated and the results are analyzed. the overall results of these features, as indicators of the relative activ...

Tectonic processes are major factors controlling landform development in tectonically active areas. In order to evaluate quantitative measurement of tectonic activities in the Alamarvdasht basin in the south of Iran, six different morphological indices including stream-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), valley floor width-valley height ratio (Vf), dra...

2002
Rossman P. Irwin Alan D. Howard

[1] Geomorphic mapping of a 1 million square kilometer section of Terra Cimmeria on Mars (1:1M scale) indicates that prolonged, intense fluvial erosion occurred during the period of heavy bombardment. Crater counts date the termination of ubiquitous, intense erosion to the late Noachian, although some valleys may have continued downcutting into the early Hesperian. Stratigraphic and topographic...

Ali Jahangiri, Reza Alipour,

Introduction The vertical and horizontal movements of the Earth crust have caused extensive changes in surface phenomena, in the active tectonic regions. In order to measure some of these changes, morphometry analyses have been used to evaluation of the amount of tectonic activity. These analyses are useful tools for analyzing existing feature at the ground level and provide a proper understan...

2010
Paul L. Heller Margaret E. McMillan Neil Humphrey

Large closed basins are often associated with regions of active tectonics. In contrast, we provide the example of the Great Divide Basin, in southern Wyoming, where climate change, through its impact on erosion and fl exure, provides the primary mechanism of basin closure. Twoand three-dimensional fl exural models that incorporate the effects of local basin abandonment due to aridity as well as...

1997
MARIA L. CALVACHE

The Guadix Basin developed as an endorheic depression during the Upper Miocene–Upper Pleistocene. Its principal palaeogeographical characteristics are a large lake in the eastern sector, an axial fluvial system and two fluvial systems transverse to it in the western sector. The uplift of a central sector of the Betic Cordillera during the Upper Pleistocene affected the study area, causing north...

2012
Shyamal Dutta Suvendu Roy

A major emphasis in geomorphology over the past several decades has been on the development of quantitative physiographic methods to describe the evolution and behavior of surface drainage networks. The quantitative analysis of morphometric parameters is found to be of immense utility in river basin evaluation. The influence of drainage morphometry is very significant in understanding the landf...

2005
Emilio Mayorga Miles G. Logsdon Maria Victoria R. Ballester Jeffrey E. Richey

Cell-to-cell surface flow paths are commonly derived from gridded digital elevation models (DEM) by choosing the direction of steepest descent to one of the eight surrounding cells. However, adequate DEMs often are not available. We developed a topography-independent method for creating gridded, land and stream drainage direction maps based on corrected vector river networks. We applied it to t...

2006
Jim E. O'Connor Gordon E. Grant Tana L. Haluska

Within the Deschutes River basin of central Oregon, the geology, hydrology, and physiography influence geomoqhic 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 basin fills and covered an...

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