Jorge D. Abad

RED YAKU - PERU

Along its 650‐km reach, the Peruvian Amazon River comprises anabranching structures, spanning from the confluence of the Marañón and Ucayali Rivers to the Peru–Brazil–Colombia border. Combining remote sensing techniques and field measurements, this research aims to understand the hydrogeomorphology of these anabranching structures. The multitempora...

The transition from the Andes to the Amazon lowland hosts a high biodiversity and currently is facing several anthropogenic activities, including hydropower infrastructure projects. Little is known about the geomorphology of the Andean gorges, rivers and the interaction with the fish diversity upstream and downstream of gorges. The Marañón River is...

The origin of the Amazon River is formed at the confluence of the Marañón and Ucayali rivers. Remote sensing and detailed hydrodynamics, sediment transport and bed morphology analysis under different hydrological conditions have been applied to understand the control mechanisms of the modern confluence, thus informing about ancient confluences. Res...

The concession of the Peruvian Amazon Waterway (PAW) project seeks to strengthen commercial transport between Brazil and Peru by using four rivers: Amazon, Ucayali, Marañón, and Huallaga, in which the Peruvian Ministry of Transportation and Communications (MTC) was in charge of developing the Terms of Reference (TOR). At the end, the TOR did not sp...

El trabajo de investigación comprendió la descripción del proceso de inundación fluvial en la Reserva Nacional Pacaya Samiria por parte de los ríos Marañón, Ucayali, Huallaga y los tributarios Tapiche, Tigres, Samiria y Pacaya. Se describe la influencia de este proceso sobre la biodiversidad y actividad pesquera, a través del transporte de flujo y...

Meandering rivers are distinguished by their characteristic sinuosity, which is subject to modulation through channel cutoff, resulting in the formation of oxbow lakes within the abandoned meander loops. Throughout the evolutionary course of a river, these cutoffs establish a connection between the channel and floodplain systems, both crucial to ma...

Meandering channels display complex planform configurations with upstream (US)‐ and downstream (DS)‐skewed bends. Bend orientation is linked to hydrodynamics, bed morphodynamic regime, bank characteristics, riparian vegetation, and geological environment, which are the modulating factors that act specially in high‐amplitude and high‐sinuosity condi...

The Peruvian Amazon is known for harboring the greatest biodiversity on the planet, with a world record for biodiversity per unit area. Previous studies suggested that the high ecological value depends on correlations between ecosystem functionality and seasonal inundation control vegetation patches. However, the knowledge on how river morphodynami...

The Ucayali River is one of the most dynamic large rivers in the world, with high rates of channel migration regularly producing cutoffs. In the lower portion of the Ucayali River, before its confluence to the Marañon River where the Amazon River is born, the increase in water and sediment discharge triggers bends with secondary channels (transitio...

Reúne los resúmenes de los trabajos presentados en el Primer Congreso Internacional sobre Amazonia Peruana: Investigación para el Desarrollo, Perspectivas y Retos (CONIAP 2020) desarrollado de manera virtual desde la ciudad de Iquitos, Perú, del 23 al 27 de noviembre del año 2020. El CONIAP contó con la asistencia virtual de más de mil personas de...

Near the Atacama Desert, Tacna city in Peru is among the largest arid cities with constant urban development, thus understanding of the urban surface thermal pattern is needed. We propose a comprehensive study of the urban heat island phenomenon, with the objective of (1) determining the spatial and temporal variations of the urban heat islands (UH...

Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by Earth’s largest and most biodiverse river basin. These services are spatially variable, hence collective impacts of newly built dams depend strongly on their configuration. We use multi...

Integrated approaches are needed to understand and respond to changes in tropical mountain ecosystems and communities brought about by receding glaciers and changes in land use. Read the full article here: https://eos.org/features/adapting-to-receding-glaciers-in-the-tropical-andes

This contribution presents MStaT, a wavelet-based open-source software developed to provide a detailed characterization of large meandering river morphodynamics. MStaT integrates three independent modules: (i) meandering morphometrics module; (ii) migration module; and (iii) confluence module. MStaT delivers a short and medium-term framework to ana...

Water-related problems affect several billion people’s lives and represent an annual challenge assessed at multitrillion US dollars, which substantiates their core role in the UN Sustainable Development Goals. Preventing direct and indirect impacts associated with water excess or water scarcity events requires expert judgement based on reliable inf...

Coastal wetlands are currently threatened by human drivers such as agriculture, infrastructure development, and urban sprawl. Pressures on these ecosystems disturb their morphology and biogeochemical cycles, resulting in the degradation of ecosystem services. However, little has been done to understand the coastal wetland response to identify effic...

One-dimensional (1D) models of open-channel flow are efficient for simulating in-channel hydrodynamics over long reaches and time periods, but cannot accurately simulate overbank flows that require two-dimensional (2D) models. The derivation and discussion of the behaviour of the coupling terms for horizontal and vertical coupling of the governing...

Bedforms-ATM (Bed forms analysis toolkit for multiscale modeling) is a software designed to hierarchize and quantify the dimensionality of natural bed forms fields. It comprises four modular applications, namely: (1) wavelet analysis, (2) Hovmöller analysis, (3) multiscale discrimination, and (4) three-dimensionality analysis. Bedforms-ATM also pro...

Meandering channels develop different geometry patterns along the floodplain during its evolution. These natural processes lead to developing lateral and longitudinal migration, describing a sort of swept that affect the human activities. As the equilibrium geometry of natural channels depends on: the flow and sediment discharge, geological conditi...

This article explores the length scales and statistical characteristics of form roughness along the outer banks of two elongate bends on a large meandering river through investigation of topographic variability of the bank face. The analysis also examines how roughness varies over the vertical height of the banks and when the banks are exposed suba...

Bedforms-ATM V1.1 is an open source software aimed to analyze the hierarchies and dimensionality of bedforms. This version encompasses four applications, namely: [1] Bed forms wavelet analysis, [2] Power Hovmoller analysis, [3] Bed forms multiscale discrimination, and [4] Three-dimensionality analysis. The full editable code, user manual, error rep...

Bedforms-ATM V1.1 is an open source software aimed to analyze the hierarchies and dimensionality of bedforms. This version encompasses four applications, namely: [1] Bed forms wavelet analysis, [2] Power Hovmoller analysis, [3] Bed forms multiscale discrimination, and [4] Three-dimensionality analysis. The full editable code, user manual, error rep...

Bedforms-ATM V1.1 is an open source software aimed to analyze the hierarchies and dimensionality of bedforms. This version encompasses four applications, namely: [1] Bed forms wavelet analysis, [2] Power Hovmoller analysis, [3] Bed forms multiscale discrimination, and [4] Three-dimensionality analysis. The full editable code, user manual, error rep...

Experimental sediment transport and river morphologic studies in laboratory flumes can use two sediment-supply methods: an imposed feed at the upstream end, or a recirculation of sediment from the downstream end to the upstream end. These methods generally produce similar equilibrium bed morphology, but temporal evolution can differ. The adjustment...

Few studies have examined the three-dimensional flow structure and bed morphology within elongate loops of large meandering channels. The present study focuses on the spatial patterns of three-dimensional flow structure and bed morphology within two elongate meander loops and examines how differences in outer bank roughness influence near-bank flow...

The upper reach of the Amazon River has a very dynamic morphology, with the highest rates of migration observed in the entire Amazon River. It has an anabranching channel pattern which alternates between a condition of single channel and anabranching structures; in particular, the anabranching structure near Iquitos City shows an interesting channe...

River meander planforms can be described based on wavelet analysis, but an objective method to identify the main characteristics of a meander planform over all spatial scales is yet to be found. Here we show how a set of simple metrics representing meander shape can be retrieved from a continuous wavelet transform of a planform geometry. We constru...

The flow and sediment transport processes near steep streambanks, which are commonly found in meandering, braided, and anastomosing stream systems, exhibit complex patterns that produce intricate interactions between bed and bank morphologic adjustment. Increasingly, multi-dimensional computer models of riverine morphodynamics are used to aid in th...

We present a study to relate the sinuosity of the main channel and its effect on the dynamics of the secondary channels of anabranching structures. For this purpose, two locations of the Peruvian Amazon River were selected: 1) a site with a medium to high-sinuosity main channel (MS site: Muyuy, Peru) and 2) a site with a low-sinuosity main channel...

These are the initial results of a satellite image analysis of the planform evolution of the geomorphology of the Peruvian Amazon River.

Past studies on river confluence dynamics are mostly based on a limited number of experimental and field data that mainly represent the morphodynamic, hydrodynamic, and sedimentary processes of alluvial river channels with limited planform activity and concentrated solely around the confluence region. The present contribution is novel and focuses o...

In the pioneering study of the Ishikari River, Japan, Kinoshita (Kinoshita 1957, 1961) described two types of meandering channels: (1) channel with two bars per meander wavelength (one bar per bend), and (2) channel with three or more bars per meander wavelength (multiple bars per bend). Based on the study of Whiting & Dietrich (1993a, b), we asses...

Laboratory experiments carried out by Abad and Garcia (2009) in a high-amplitude Kinoshita meandering channel show bed morphodynamics to comprise steady (local scour and deposition) and unsteady (migrating bedforms) components. The experiments are replicated with a numerical model. The sediment transport formulation was calibrated using the sedimen...

Recently, it was observed that migrating bed forms produce temporal and spatial peaks of shear stresses along the outer bank of an experimental meandering channel. These stresses are about 50% larger than the shear stresses exerted by the mean near-bank flow. Because of this increase in bank shear stress the migration rate of the bend may be signif...

Most of the past studies on river confluences dynamics are based on a limited number of experimental and field data that mainly represent the morphodynamic, hydrodynamic and sedimentary processes of alluvial river channels with limited planform activity. Moreover, these studies are concentrated mainly around the confluence region. This novel contri...

Meander migration and planform evolution depend on the resistance to erosion of the floodplain materials. To date, research to quantify meandering river adjustment has largely focused on resistance to erosion properties that vary horizontally. This paper evaluates the combined effect of horizontal and vertical floodplain material heterogeneity on m...

The continuous wavelet transform is applied to the analysis of curvature signals from both synthetic meanders and 52 realizations from 16 natural meanders ranging from class B to class G (Brice classification), thus providing information on the spatial distribution of their arc-wavelength spectrum, and therefore, representing an objective character...

Whiting and Dietrich [2] conducted a series of laboratory experiments to investigate multiple bars and pools in a sine-generated, large-amplitude channel. 3.65 m 4.9 m 0.25 m (Qin) (Hout) Based on their findings, we numerically reproduced the 2D and 3D morphodynam-ics structures in large-amplitude meandering channels found by Whiting and Dietrich....

The Madeira River is the largest tributary in water discharge and sediment transport of the Amazon River. At present, this river is at the center of a controversial political discussion because the Brazilian government is building two hydroelectric plants on the Bolivia-Brazil border, flooding a long reach from near Cachuela Esperanza in the tribut...

Bank erosion is a process present in rivers of all the scales and is a key aspect in the evolution of meandering streams. Its magnitude is significantly controlled by the resistance-to-erosion properties of the floodplain materials, which themselves are modified by the varying presence of riparian vegetation. Earlier studies have stated that the ph...

It is well known that the presence of vegetation or log jams decreases the bank shear stress exerted by the water on a river. This fact is used in river restoration to design bank erosion control structures such as engineered log jams or streambank revegetation zones. Also it has been observed in small rivers the presence of exposed near-bank roots...

Most of the fluvial channels present bedforms such as dunes and ripples which are product of the interaction between hydrodynamics and sediment transport. Although, the effect of this bedforms has been studied by several researchers, very little has been done to study the ripple-dune transition. The purpose of the present study is to extend the obs...

Fluvial channels present bed forms such as dunes and ripples that alter instantaneous hydrodynamics parameters such as flow velocities, water surface profiles, bed shear stresses, and Reynolds stresses and create turbulent coherent structures that are significantly different from those presented in flat bed conditions. It is known that LES-based mo...

[1] There is no standard nomenclature and procedure to systematically identify the scale and magnitude of bed forms such as bars, dunes, and ripples that are commonly present in many sedimentary environments. This paper proposes a standardization of the nomenclature and symbolic representation of bed forms and details the combined application of ro...

An in‐house fully three‐dimensional general‐purpose finite element model is applied to solve the hydrodynamic structure in a periodic Kinoshita‐generated meandering channel. The numerical model solves the incompressible Reynolds‐averaged Navier–Stokes equations for mass and momentum, while solving the k − ε equations for turbulence. The free surfac...

Unconventional natural gas resources offer an opportunity to access a relatively clean fossil fuel that could potentially lead to energy independence for some countries. Horizontal drilling and hydraulic fracturing make the extraction of tightly bound natural gas from shale formations economically feasible. These technologies are not free from envi...

The flow characteristics around two partially buried objects, a short cylinder (SC) and a truncated cone (TC) were examined experimentally and numerically. Experiments were conducted in a large tilting flume with vertical walls made of acrylic plastic and steel floor covered by a 24-m long sand pit. For each experiment, the object was placed on a f...

The Tropical Rivers 2012 international conference (http://www.crearamazonia.org/tropicalrivers2012/) was part of the International Geoscience Programme 582 project of The United Nations Educational, Scientific and Cultural Organization's International Union for Geological Sciences (UNESCO-IUGS). The aim of the IGCP 582 is to provide an integrated a...

Meandering evolution is modeled integrating a 2d flow hydrodynamic and bed evolution models, with other submodels for description of the bank erosion and accretion processes. A desirable characteristic of the hydrodynamic and bed evolution models is that they may use irregular grids, with the aim of having an accurate description of the banks, and...