نتایج جستجو برای: multiple drainage basin
تعداد نتایج: 850575 فیلتر نتایج به سال:
BACKGROUND The prognostic significance of multiple draining basins is controversial in melanoma because analyses have not adequately controlled for standard prognostic variables. We hypothesized that an analysis based on prognostically matched pairs of patients with multiple versus single drainage basins would clarify any independent role of basin number. STUDY DESIGN We identified patients i...
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...
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...
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...
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...
Integrated simulation of water resources systems is an efficient tool to evaluate and adopt various options in macro-policies and decision-making procedures that are in line with the sustainable development of drainage basins. One of the drainage basin management policies is to enhance the efficiency of agricultural land use. Considering the complicated function of the drainage basin elements a...
Approximately 5.5 x 109 g (4.0 x 105) of mercury was discharged into the Carson River Drainage Basin of west-central Nevada during processing of the gold- and silver-rich Comstock ore in the late 1800s. For the past 13 decades, mercury has been redistributed throughout 500 km2 of the basin, and concentrations are some of the highest reported values in North America. This article documents the c...
The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, alt...
Morphotectonic investigations were carried out by the use of morphometric indices which serve as a tool of identification in regions with active tectonic warp. Landforms in active deformation area are produced from relations of tectonic and surficial processes. One of the most significant landforms underground is rivers that are extremely responsive to tectonic movements mainly uplift and tilti...
converting rangelands to arable land such as dry farming is widely practiced in many places in iran. this activity could possibly contribute to the increase in downstream sedimentation. the effects of this activity on downstream watersheds are not well documented for many strategic areas in the country. one such area which is proposed for this study is the kardeh drainage basin, located in the ...
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