Impacts of Land-Use and Land-Cover Change on River Systems (original) (raw)
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9.37 Impacts of Land-Use and Land-Cover Change on River Systems
Treatise on Geomorphology, 2013
Human land-use activities have fundamentally changed the hydrogeomorphology of rivers. Since the late Holocene, anthropogenic changes to alluvial stratigraphy and channel morphology have often been greater than those left by climate change. This chapter reviews four general topics related to land use: (1) landscape sensitivity and scale; (2) changes to processes of flood generation, soil erosion, sediment sequestration, and sediment yields; (3) how accelerated water, erosion, and sediment deliveries transform fluvial systems; and (4) the long-term history of land-use change impacts following the Neolithic advent of agriculture and its spread. In covering these topics, the chapter introduces the newly emerging field of land-change science.
The human role in changing fluvial systems: Retrospect, inventory and prospect
Geomorphology, 2006
Historical and modern scientific contexts are provided for the 2006 Binghamton Geomorphology Symposium on the Human Role in Changing Fluvial Systems. The 2006 symposium provides a synthesis of research concerned with human impacts on fluvial systemsincluding hydrologic and geomorphic changes to watershedswhile also commemorating the 50th anniversary of the 1955 Man's Role in Changing the Face of the Earth Symposium [Thomas, Jr., W. L. (Ed.), 1956a. Man's Role in Changing the Face of the Earth. Univ. Chicago Press, Chicago. 1193 pp]. This paper examines the 1955 symposium from the perspective of human impacts on rivers, reviews current inquiry on anthropogenic interactions in fluvial systems, and anticipates future directions in this field.
The 2006 Binghamton Geomorphology Symposium on The Human Role in Changing Fluvial Systems
Geomorphology, 2006
Historical and modern scientific contexts are provided for the 2006 Binghamton Geomorphology Symposium on the Human Role in Changing Fluvial Systems. The 2006 symposium provides a synthesis of research concerned with human impacts on fluvial systemsincluding hydrologic and geomorphic changes to watershedswhile also commemorating the 50th anniversary of the 1955 Man's Role in Changing the Face of the Earth Symposium [Thomas, Jr., W. L. (Ed.), 1956a. Man's Role in Changing the Face of the Earth. Univ. Chicago Press, Chicago. 1193 pp]. This paper examines the 1955 symposium from the perspective of human impacts on rivers, reviews current inquiry on anthropogenic interactions in fluvial systems, and anticipates future directions in this field.
Quaternary Science Reviews, 2010
Since the late 1980s our understanding of the relationship between climate, land-use and Holocene river development in Britain has changed radically. Conceptually simplistic and data-poor models of peopleriver environment interaction, many of which considered human activity alone to be the control of Holocene flooding and alluviation, have been replaced by more data-rich models that explain river behaviour in terms of a continuum of climate and anthropogenic drivers, individually operating over a range of temporal and spatial scales. One of the key factors in this paradigm shift has been the significant increase in the number of 14 C-dated fluvial units that has itself recently facilitated the application of meta-analysis techniques to large fluvial data sets. These analyses have produced the first probability-based national and regional reconstructions of Holocene flooding in the British Isles that can be correlated with independent, high-resolution hydro-climate records. This paper critically reviews the major findings of this new research focusing on process-based causality relationships in fluvial systems and quantifying how environmental signals are propagated in river basins and preserved in landform and sedimentary sequences. By using cumulative probability density function (CPDF) plots of fluvial 14 C dates that have been classified on the basis of sedimentary environment and evidence for changing depositional regime, 17 multi-centennial length periods of flooding and river instability during the Holocene are identified in the UK. The scale and timing of these episodes vary regionally and correlations can be made with a range of climate proxy records, including the North Atlantic drift-ice index, glacier variations in Europe, and mire surface wetness and water-table reconstructions. A new analysis of overbank floodplain sedimentation rates points to an acceleration after ca 1000 cal. BP, which can be related to the agricultural revolution of the Middle Ages. This is the first time that an unequivocal anthropogenic signal, affecting most British rivers, can be recognised in the Holocene fluvial record of the UK and it appears to have been a broadly synchronous 'event' in many catchments.
CATENA, 2020
Large rivers on the Iberian Peninsula reflect a long-history of human interventions and natural disturbances in the fluvial corridors and on the surrounding valleys. In this study we aim to characterize the river morphology in pre-regulation times and understand the morphological changes of the large river Tagus (Central Portugal), across space and time. For this, we used comparable military thematic maps from three dates (1855, 1940 and 2000) and evaluated the river landforms, including sinuosity, aquatic, geomorphic and riparian aspects, in three geomorphological zones (Upland, Middle, and Lowland) using a Geographic Information System (GIS). We related the landform variations to the hydrological alterations and to Land-use Land-Cover (hereinafter LULC) changes at valley level. Hydrological data were achieved by simulating river flow regime using the Soil and Water Assessment Tool (SWAT) model. LULC data was obtained by on-screen digitizing of the military thematic maps complemented with ancillary bibliographic information. Metrics for channel form, aquatic and riparian features were quantified in 51 sampling units of 2500 m-long river sections for each period to describe the river morphology. Shannon-Wiener Index (H') was applied as a descriptor of the morphological diversity. Data analysis revealed a narrowing of the main channel, an overall reduction of the sinuosity, a smaller number of instream geomorphic units and abandoned lateral channels on the most recent period. Morphological alterations were driven primarily by the reduction of floods and sediment inputs, caused by streamflow regulation, while the agricultural intensification, the augment of forest plantations and the reduction of the Mediterranean scrublands induced changes in sediment dynamics and altered the riparian connectivity. The Upland zone showed the highest morphological alterations switching from a historical high-energy section to a low-dynamic zone. We also observed a high morphological variability in the Middle course exhibiting multifaceted gradients of change, while the Lowland zone reflected continuous but less pronounced modifications. River management planning should express the insights of how past and present human alterations affect morphological processes in river-floodplain systems, particularly taking into account river zones' specificities and how they may react or constrain potential restoration processes.
Alluvial responses to the changing Earth system
Earth Surface Processes and Landforms, 2008
Alluvial systems are complex, self-organizing and hierarchical in structure. They represent stored and transitory sediment bodies transported by rivers that have eroded their catchments and created multiscalar landforms and sedimentary architectures over a range of time-scales. The central question we address in this paper is how environmental signals are autogenically processed and recorded by the fluvial sediment system. We compare databases of alluvial units that are well constrained in terms of dating control with direct or proxy records of environmental change. River system responses to environmental change are evaluated over three nested time periods spanning the past 200 000 years. First, focusing on Mediterranean European and African catchments, river responses to relatively abrupt and short-term Late Pleistocene Dansgaard-Oeschger and Heinrich climate events are examined. Second, the effects of rapid and globally significant episodes of Holocene climate change on European rivers, together with anthropogenic land-use impacts, are assessed. Last, 'Little Ice Age' flooding and alluvial responses to modern climate warming are reviewed with particular reference to upland Britain. These studies are shown to have significant implications for modelling local, regional and global-scale alluvial responses to future environmental change. They highlight the necessity for numerical simulation models to be fully informed by fieldbased knowledge and understanding of the memory effects of whole fluvial sediment systems, particularly those that have experienced repeated phases of environmental change.
Progress in Physical Geography: Earth and Environment, 2018
Global perspectives on the complexities of environmental change impacts associated with past and present human activity are needed for the food and water security challenges of the twenty-first century. This is especially true for rivers, for which the onset and persistence of a range in human activities, altering their function and form, have been temporally and spatially variable. Ancient civilisations, states and empires extended geographically to cover sub-continental areas where their river modifying activities became linked to regional Earth system stresses arising from climate and land use change. We present a new interpretative framework for characterising and classifying human impact on river systems, emphasising that this has taken place over decadal to millennial time periods on a sub-continental scale. This 16-element classification and documentation of different human transformations, including land management, urbanisation, industry and engineering activities, is used ...