کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8908233 1635347 2018 57 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Recent geomorphological evolution of a natural river channel in a Mediterranean Chilean basin
ترجمه فارسی عنوان
تحول ژئومورفولوژیکی اخیر کانال رودخانه طبیعی در حوزه دریای مدیترانه شیلی
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی
In this paper we analyse the recent geomorphological evolution of the River Ñuble, an unmodified wandering river in the Mediterranean region of Chile, highlighting the relation between the observed hydroclimatic trends in the region and the morphology of the river. The work documents the recent changes (2003-2016) in channel morphology (i.e., narrowing, simplification, vegetation encroachment) and, in particular, how the river has progressively reduced its geomorphic activity during the last decade. Changes have been detected using aerial imagery and quantified by means of a series of channel form indices that allow tracking the geomorphological evolution of an 8-km river segment. The catchment has experienced a clear decrease in the frequency and magnitude of flood events, although this fact is not fully supported by a generalized reduction in the analysed rainfall series. We relate the observed river relaxation and the associated channel changes with the reported period of low hydroclimatic activity, which follows a humid period that occurred in the Pacific region during the 1970s and 1980s, connected to the PDO (Pacific Decadal Oscillations) that particularly affected the northern and the central parts of Chile. Altogether, this resulted in generalized river stability and a simplification of the drainage pattern of the channel. In absence of river training practices and other major changes in the catchment, the reduction of formative discharges appears thus to be the main control of the recent evolution of this gravel-bed river.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geomorphology - Volume 303, 15 February 2018, Pages 322-337
نویسندگان
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