This extensively revised and updated edition continues to present an engaging and comprehensive introduction to the subject, exploring the world's landforms from a broad systems perspective. It reflects on the latest developments in the field and includes new chapters on geomorphic materials and processes, hillslopes and changing landscapes.

prinsip geomorfologi

This extensively revised and updated edition continues to present an engaging and comprehensive introduction to the subject, exploring the world's landforms from a broad systems perspective. It reflects on the latest developments in the field and includes new chapters on geomorphic materials and processes, hillslopes and changing landscapes.

The Geographical Journal, 1997

An understanding of landforms may be of great use, directly or indirectly, to human beings who are influenced by and, in turn, influence the surface features of the earth which they inhabit. If landforms are properly interpreted, they throw light upon the geologic history, structure and litho logy of a region. According to D.K.C. Jones, applied geomorphology could be defined as " the application of geomorphic understanding to the analysis and solution of problems concerning land occupancy, resource exploitation, and environmental management and planning ". Indeed, all geomorphological knowledge tends to be applied, according to R.G. Craig and J.L. Craft. As each advance in knowledge provides a clear view of how the earth works, geomorphologists can make use of the knowledge for evaluating resources, development projects, locating natural hazards and mitigating the effect of natural disasters. Geomorphic knowledge and techniques may be applied in the following areas: i. Studying the impact of geomorphic/ environmental processes on human society and activities and dealing with problems arising out of such impact; ii. Investigating the changes brought about in the geomorphic/environmental processes by human activities and dealing with the problems arising out of such interaction; iii. Managing resources and monitoring changes in the geomorphic system to suggest suitable remedial measures for maintaining development at a sustainable level. Two Main Lines of Application: The application of geomorphology, according to Charley, Schumn and Sugden, may be considered along two lines: (i) Geomorphology can be an aid to resource evaluation, engineering construction and planning. In this category we may put resource inventories, environmental management, soil and land evaluation, production of maps for hydrological, erosional and stability control, geomorphic mapping, mapping for land systems and evaluating terrain, classification and retrieval of information on terrain and other matters of use to earth scientists, engineers and planners. Applied geomorphology in this aspect can be of use in urban planning in different geomorphic environments and in preparation of natural hazard maps, morpho-agricultural regionalisation, land use planning, construction and management of roads. (ii) Applied geomorphology is also concerned with human beings as geomorphic agents, in terms of their planned or inadvertent effects on geomorphic processes and forms. Human beings have over time tried to tame and modify geomorphic/environmental processes to suit their economic needs. Embankments have been built to check flooding of rivers; meandering courses of rivers have been straightened and channels diverted; coastal areas have been sought to be protected against wave erosion by building walls; there have been attempts to stabilise sandy areas through plantation, and check soil erosion through afforestation. These are some examples of planned activities by human beings that have an impact on geomorphic forms and processes.

This paper reports a study of the Tista megafan in the foothills of Darjeeling Himalaya. Spread over parts of India and Bangladesh, the megafan is bounded by the Mahananda River to its west and the Tista River to the east. The Atrai and Karatoya Rivers flow through its axial part. The megafan covers an area of~18,000 km 2 . Near its apex the surface slope is~0.19°, that declines to 0.01°near the toe. The east-west transverse profile of the megafan is broadly upward convex, with gently sloping (~0.01°) flanks. Maximum width and the length of the megafan are about 145 km and 166 km respectively. The highest point near the megafan apex is~150 m above the Brahmaputra alluvial plain. The Tista River flanking the megafan has an average annual discharge of 609 m 3 /s with highest average monthly discharge exceeding 2000 m 3 /s during monsoon. Most of the other channels currently traversing the megafan are plains-fed, and compared to Tista and Mahananda Rivers these channels have lesser discharge, higher sinuosity, and decreased widths. A radiating network of abandoned channel belts can be identified in satellite images of the megafan. Each of these major paleochannels is associated with numerous crevasse channels in the distal part of the megafan, forming an intricate network of radial drainage on the megafan surface. Three distinct depositional lobes can be recognised on the Tista megafan. Each of the lobes is identified by a set of ancient and modern radial drainage systems. The lobe boundaries are marked by discordance in drainage network of adjacent lobes. The relative ages of the lobes, as tentatively determined from the drainage discordances, indicate that the megafan first built up the eastern lobe (lobe 1), then shifted to the west to form lobe 2, and finally switched again eastward giving rise to the smallest lobe located close to the mountain front (lobe 3). Although broadly upward convex in cross profiles, subtle reflections of multiple lobes are apparent in some of the cross profiles. Study of the old maps published between 1794 and 1945 reveals that some of the present-day plains-fed rivers, like the Tangon, the Atrai and the Karatoya, were directly connected to the Himalayan catchment basins prior to the late eighteenth century. Archaeological excavations along the banks of these rivers appear to support this paleodrainage configuration. Eight facies and five facies associations were recognised in the uppermost megafan sediments. Facies associations suggest deposition from high-energy sandy streams in the proximal area and deposition from mixed load, sinuous streams and flanking marsh or lake in the distal part of the lobes. Paleocurrent data are consistent with a southwestward spreading paleochannel pattern recognised within the studied part of the megafan. Multiple lobes typify megafans ocurring in different parts of the globe. The existence of the mutiple accretionary lobes in Tista megafan, its radial drainage pattern, its concave-upward longitudinal and convex-upward transverse profile shape make it morphologically comparable with other high-gradient alluvial fans observed in nature and those produced in the laboratory. These morphological features denote the similarities between the small, highgradient alluvial fans and large, low-gradient megafans, and that in turn may be indicative of the commoness in certain controlling factors between these two depositional systems.

This extensively revised and updated edition continues to present an engaging and comprehensive introduction to the subject, exploring the world's landforms from a broad systems perspective. It reflects on the latest developments in the field and includes new chapters on geomorphic materials and processes, hillslopes and changing landscapes.