Field and Satellite Images-Based Investigation of Rivers Morphological Aspects

Abstract

Worldwide and especially in less developed regions, process-based evaluations and/or geomorphological information on large-scale rivers are still scarce. Such investigation become of ‎urgent ‎need due to the climate change and expected occurrence of extreme floods and drought which ‎may ‎threaten the safety of nearby and downstream cities, especially in regions that are highly sensitive and ‎affected by climatic changes. The Tigris River, in Iraq, is one such river that has undergone significant alteration to its flow and morphologic aspects due to climate change and the construction of many dams. However, morphology and its change for many reaches of this river are still uninvestigated. To this end, field and satellite-based investigations into the morphology of a reach located between Makhool District and Tikrit City have been conducted. In addition to the cross-sectional survey-based determination of the reach geometrical aspects, a sinuosity indices-based evaluation of the reach planform was implemented, utilizing a satellite indices-based approach. Furthermore, the characteristics of bed material were identified through field sampling. Investigation results show that the reach has a steep bed slope and many islands of low altitude with an elongated shape. The reach has a mild sinuosity with alternating bars. The dominant particle sizes of the bed material are coarse and medium gravel with a dominant particle shape of disc particles. Moreover, the satellite-based change detection indicated the fading out and disappearance of some secondary channels, the growth of many islands, and the movement of some bends downstream. The percentage of changing parts for the period 1975–2021 is 14%. Most of this change, 11%, occurred after the construction of the Mosul Dam. This reveals the sensitivity of reach morphology to flow change due to the construction of dams. The conducted fieldwork and the applied methodology contribute to supporting efforts to add knowledge worldwide about uninvestigated rivers. Doi: 10.28991/CEJ-2022-08-07-03 Full Text: PDF

Classification of River Sediment Fractions in a River Segment including Shallow Water Areas Based on Aerial Images from Unmanned Aerial Vehicles with Convolution Neural Networks

“…Research on the application of deep learning to satellite images and aerial photography is progressing [22], and the detection of not only land cover but also features such as buildings [23][24][25], roads [26][27][28], and land cover [29][30][31], is available. Major examples of semantic segmentation as applied to rivers are the river channel detection and the river width measurement using satellite images [32][33][34]. As for the examples related to river management, there have been attempts to detect estuary sandbars [35], to monitor water levels during floods [36][37][38][39], to conduct the water binary segmentation task to aid in fluvial scene autonomous navigation [40], and to detect fine-grained river ice [41].…”

Monitoring and Modelling Morphological Changes in Rivers Using RS and GIS Techniques

“…In the literature, many international studies were carried out to identify the morphological and spatio-temporal pattern of the river planform and their bankline migration with the aid of GIS and remote sensing tools [13][14][15][16][17][18]. Remote sensing has been used by researchers for more than thirty years to investigate the surface of the earth [19], of which supervised remote sensing techniques have been widely used for the analysis of satellite images.…”

“…For example, in the river delta in Turkey [20], the Nile River delta in Egypt [21,22], and many others. In this study, the temporal and spatial changes in the Euphrates River uses Landsat-3 MSS: 1985, Landsat-5 TM: 1990, 1995, 2000, 2005, and Landsat-8 OLI: 2010, 2015, 2021, 2022 were employed to map river planform changes along 5 km of river length upstream and 5 Km downstream of the Abbassia reach. The morphological changes were analyzed using Remote Sensing (RS) and Geographical Information System (GIS) techniques for 49 years between 1976 and 2022.…”

Spatial Morphological Characteristics and Evolution of Policy-Oriented Urban Agglomerations—Take the Yangtze River Middle Reaches Urban Agglomeration as an Example

“…Recently, there has been growing advocacy among research scholars for a renewed focus on the spatial entity of an urban agglomeration. Scholars have tended to identify changes in the material spaces from the perspective of land use and cover with the help of satellite images [8,9]. By analyzing the forms of urban agglomeration, a deeper understanding of the process of spatial agglomeration and diffusion can be achieved using GIS [10][11][12], eventually leading to clear policy recommendations [13][14][15].…”