Artykuły w czasopismach na temat „Catchment geomorphology”
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1
Andrews, E. D., T. P. Burt i D. E. Walling. "Catchment Experiments in Fluvial Geomorphology". Arctic and Alpine Research 17, nr 3 (sierpień 1985): 349. http://dx.doi.org/10.2307/1551025.
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Behnke, J. J. "Catchment experiments in fluvial geomorphology". Earth-Science Reviews 22, nr 2 (wrzesień 1985): 157. http://dx.doi.org/10.1016/0012-8252(85)90022-4.
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Gericke, Ockert J. "GIS Applications to Investigate the Linkage between Geomorphological Catchment Characteristics and Response Time: A Case Study in Four Climatological Regions, South Africa". Water 11, nr 5 (23.05.2019): 1072. http://dx.doi.org/10.3390/w11051072.
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In flood hydrology, geomorphological catchment characteristics serve as fundamental input to inform decisions related to design flood estimation and regionalization. Typically, site-specific geomorphological catchment characteristics are used for regionalization, while flood statistics are used to test the homogeneity of the identified regions. This paper presents the application and comparison of Geographical Information Systems (GIS) modelling tools for the estimation of catchment characteristics to provide an enhanced understanding of the linkage between geomorphological catchment characteristics and response time. It was evident that catchment response variability is not exclusively related to catchment area, but rather associated with the increasing spatial–temporal heterogeneity of other catchment characteristics as the catchment scale increases. In general, catchment and channel geomorphology overruled the impact that catchment variables might have on the response time and resulting runoff. Shorter response times and higher peak flows were evident in similar-sized catchments characterized by lower shape factors, circularity ratios, and shorter centroid distances and associated higher elongation ratios, drainage densities and steeper slopes. The GIS applications not only enabled the inclusion of a more diverse selection of catchment characteristics as opposed to when manual methods are used, but the high degree of association between the different GIS-based methods also confirmed their preferential use.
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Conacher, Arthur. "A Role for Geomorphology in Integrated Catchment Management". Australian Geographical Studies 40, nr 2 (lipiec 2002): 179–95. http://dx.doi.org/10.1111/1467-8470.00173.
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Trotter, Eleonora H. "Woody Debris, Forest-Stream Succession, and Catchment Geomorphology". Journal of the North American Benthological Society 9, nr 2 (czerwiec 1990): 141–56. http://dx.doi.org/10.2307/1467447.
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Quesada-Román, Adolfo. "Geomorphology of the Guacimal River catchment, Costa Rica". Journal of Geography and Cartography 5, nr 2 (25.06.2022): 58. http://dx.doi.org/10.24294/jgc.v5i2.1673.
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The Guacimal River catchment has an area of 181 km2 and is located in the NW of Costa Rica, between the coordinates 84.745° W-10.016° N and 84.909° W-10.325° N. In this territory, as in most of the country, detailed geomorphological studies are scarce; therefore, the objective of this paper is to present the geomorphological mapping at a scale of 1:25,000 of the Guacimal River, which allows us to explain the dynamics of the agents involved in the modeling of the catchment. The work methodology consisted of three stages: pre-mapping, field activity and post-mapping, which resulted in a map in which ten relief forms are represented, ordered according to their morphogenesis in endogenous modeled and exogenous (fluvial, gravitational and littoral). This document will be the base line for land use planning, both continental and coastal, and for local risk management.
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Helliwell, R. C., M. C. Coull, J. J. L. Davies, C. D. Evans, D. Norris, R. C. Ferrier, A. Jenkins i B. Reynolds. "The role of catchment characteristics in determining surface water nitrogen in four upland regions in the UK". Hydrology and Earth System Sciences 11, nr 1 (17.01.2007): 356–71. http://dx.doi.org/10.5194/hess-11-356-2007.
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Abstract. Hydrochemical and catchment data from 80 upland moorland sites in four regions with contrasting climate, soils, geology and geomorphology have been analysed to assess the key catchment attributes that influence enhanced leaching of soluble nitrogen to surface waters. The regions are the South Pennines of northern England, the Snowdonia National Park in north Wales, the Galloway region of south-west Scotland and the Mourne Mountains in Northern Ireland, all highly acidified, with median pH values of <5.5. Linear regression of mean summer and winter concentrations for nitrate (NO3−), ammonium (NH4+), dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) were expressed as functions of catchment attributes. Nitrate concentrations in waters draining catchments dominated by peaty soils (large C pool) were much less than those in catchments dominated by mineral soils (small C pool). Hence, if future N deposition levels are maintained or increase, high-altitude catchments with small carbon pools are potentially more susceptible to NO3− leaching. All N species exhibit seasonality; this is most marked in Galloway and least marked in the South Pennines, which implies that the South Pennines have reached an advanced stage of N saturation. Surface water inorganic N concentrations and the ratio of dissolved organic carbon (DOC) to dissolved organic N (DON) can be related to deposition inputs, although relationships differ throughout the year. If the DOC/DON ratio is indicative of catchment N saturation, levels of N retention are at least partially determined by deposition levels. This study identifies N deposition as a major inter-regional control on the degree of catchment N saturation and on N leaching to surface waters; it stresses the importance of catchment factors in modifying the relationship between N deposition and leaching in acid sensitive UK upland catchments.
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Vietz, Geoff J., Christopher J. Walsh i Tim D. Fletcher. "Urban hydrogeomorphology and the urban stream syndrome". Progress in Physical Geography: Earth and Environment 40, nr 3 (7.10.2015): 480–92. http://dx.doi.org/10.1177/0309133315605048.
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The urban stream syndrome is an almost universal physical and ecological response of streams to catchment urbanization. Altered channel geomorphology is a primary symptom that includes channel deepening, widening and instability. While the common approach is to treat the symptoms (e.g. modifying and stabilizing the channel), many stream restoration objectives will not be achieved unless the more vexing problem, treating the cause, is addressed in some way. Research demonstrates that the dominant cause of geomorphic change in streams in urban catchments is an altered flow regime and increase in the volume of stormwater runoff. Thus, managers can choose to treat the symptoms by modifying and controlling the channel to accommodate the altered flow regime, or treat the cause by modifying the flow regime to reduce the impact on channel morphology. In both cases treatments must, at the least, explicitly consider hydrogeomorphology—the science of the linkages between various hydrologic and geomorphic processes—to have a chance of success. This paper provides a review of recent literature (2010 to early 2015) to discuss fluvial hydrogeomorphology in the management of streams subject to urbanization. We suggest that while the dominant approach is focused on combating the symptoms of catchment urbanization (that we refer to as channel reconfiguration), there is increasing interest in approaches that attempt to address the causes by using stormwater control measures at a range of scales in the catchment (e.g. flow-regime management). In many settings in the oft-constrained urban catchment, effective management of stream morphology may require multiple approaches. To conclude, we identify five research areas that could inform urban hydrogeomorphology, one of the most challenging of which is the extent to which the volume of excess urban stormwater runoff can be reduced to mitigate the impact on stream geomorphology.
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Barker, Charles, i Gawie De Villiers. "A philosophical basis for the holistic study of landscape development in Geomorphology". Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 27, nr 3 (16.09.2008): 165–82. http://dx.doi.org/10.4102/satnt.v27i3.89.
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The development of Geomorphology from two former major disciplines (Geography and Geology),makes it difficult for practitioners to accept a single major meta-paradigm as is the case with other earth sciences. It is also clear from current developments in the discipline, that the move away from the traditional qualitative research in micro-scale environments left a methodological gap in investigations into larger (meso-scale) phenomena. In this article, paradigms and science are examined with special reference to Geography as one of the parental sciences of Geomorphology (a view which is largely held in South Africa). After an elucidation of a meta-paradigm for Geomorphology, this meta-paradigm is then discussed in greater detail. Critical issues such as time and space and the way in which they are treated in Geomorphology are considered. Five social paradigms (functionalism, positivism, pragmatism, realism and the general systems theory or holism) used in Geomorphology are explained in as far as they have been applied to the discipline in the past. These are then linked to philosophical concepts and research approaches in landscape development in particular. The historical evolution of landscape development studies and principles of landscape development such as quantitative methods, antagonism, stability, equilibrium, catena’s, directedness, tectonics, and environmental variables provide the foundation from which the authors formulate a philosophical basis, “systemic realism”, for the integration of process and historic-genetic studies in Geomorphology. Several criteria are given for testing the proposed methodology, based on the components from which the approach was formulated. Results from a case study done on the Modder River catchment in the central Free State are compared with the suggested approach. Firstly, a conceptual model of the catchment is discussed. The identification of possible causal processes and environmental conditions is made from the conceptual model, previous studies and the spatial distribution of land forms and geological features in the catchment. Finally, some light is shed on the possible future development of the landscape. It is the authors’ contention that systemic realism forms a sound basis for future research in landscape development and, from there, provides a guideline to resource management.
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Shand, P., A. H. Haria, C. Neal, K. J. Griffiths, D. C. Gooddy, A. J. Dixon, T. Hill, D. K. Buckley i J. E. Cunningham. "Hydrochemical heterogeneity in an upland catchment: further characterisation of the spatial, temporal and depth variations in soils, streams and groundwaters of the Plynlimon forested catchment, Wales". Hydrology and Earth System Sciences 9, nr 6 (31.12.2005): 621–44. http://dx.doi.org/10.5194/hess-9-621-2005.
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Abstract. The heterogeneous nature of upland hard-rock catchments in terms of geology, geomorphology, superficial deposits, soil type and land use gives rise to a range of hydrochemical characteristics in stream waters. This is further complicated by the large and often rapid changes in stream flow typical of storm events. The sources of solutes and flow pathways in hard-rock catchments are still poorly understood, in particular the role of bedrock groundwater. Spatial variations in water chemistry are presented for stream waters, soils and groundwaters in the forested Plynlimon catchment of Wales, UK. The results highlight a large degree of spatial heterogeneity in each of these systems. This has major implications for the application of end-member mixing analysis and presents serious problems for modelling in scaling up from study sites to catchment scale. However, such data provide important constraints on sources, flow pathways and residence times within individual catchment compartments, knowledge of which is essential for understanding how such catchments function. The characterisation of sub-surface waters in upland catchments requires a great deal of care during sampling as well as high spatial and temporal resolution of sampling, and further work is required to characterise the Plynlimon catchments fully. Nevertheless, the presence of an active and highly stratified groundwater system is considered important as a source of solutes and water to streams. It also provides a storage medium that is likely to make a major contribution to explaining the strongly damped rainfall Cl and d2H signals measured in the streams.
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(Oprea) Constantin, Dana Maria, Emil Cîrciumaru i Victor Viorel Vătămanu. "The Land’s Susceptibility, Due to Atmospheric Precipitations, Within the Catchment Area of Câlnău". Present Environment and Sustainable Development 8, nr 1 (1.05.2014): 45–57. http://dx.doi.org/10.2478/pesd-2014-0004.
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Abstract The climatic factors, generally, and the precipitation amounts recorded, especially, constitute some of the factors which condition the development and intensity of actual geomorphologic processes. One of the most employed climatic parameters for determining the land’s susceptibility to atmospheric precipitations, with real and concrete applications into the dynamic geomorphology, is the Angot factor. The precipitations represent a crucial meteorological element in initiating, sustaining and reactivating some geomorphologic processes, acting as a modelling agent for every type of landscape. This influence can be highlighted by quantifying the values of some characteristic variables (length, frequency and intensity), as well as temporally confining individual and successive sequences, which present a certain degree of susceptibility. The general objective of this research, through the analysis of precipitations and the Angot parameter, is to identify, on one hand, the months, seasons or years with a very high or very low susceptibility to the occurrence of bank erosion phenomena, and on the other, to examine the value variations of this parameter across the year. The purpose is to recognize a cumulative of pluviometric conditions which could contribute to inducing, in general, the modelling processes. The study of land’s susceptibility to atmospheric precipitations was conducted within the morpho-hydrographic drainage system of Câlnău.
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Beven, Keith. "Towards the use of catchment geomorphology in flood frequency predictions". Earth Surface Processes and Landforms 12, nr 1 (styczeń 1987): 69–82. http://dx.doi.org/10.1002/esp.3290120109.
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Srinivasa Raju, K., D. Nagesh Kumar i Anmol Jalali. "Prioritization of sub-catchments of a river basin using DEM and Fuzzy VIKOR". H2Open Journal 1, nr 1 (1.07.2018): 1–11. http://dx.doi.org/10.2166/h2oj.2017.001.
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Abstract Fuzzy VIKOR, a decision making technique, is applied to prioritize 224 sub-catchments of Mahanadi Basin, India. Seven geomorphology based criteria viz., drainage density, bifurcation ratio, stream frequency, texture ratio, form factor, elongation ratio and circulatory ratio are estimated from five digital elevation models (DEMs). Triangular membership functions were formulated for each criterion for each sub-catchment which are based on individual values obtained from individual DEM's. Entropy method is employed for estimation of weights of criteria and a similar mechanism is followed while formulating triangular membership function for weights. Eight groups are formulated with a number of sub-catchments in each group as 5, 26, 69, 65, 29, 11, 12, 7 for taking up conservation measures. Effect of varying strategy weight, (ν) on the ranking pattern is also studied and found that ν value effects ranking pattern significantly.
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Hergarten, S., J. Robl i K. Stüwe. "Tectonic geomorphology at small catchment sizes – extensions of the stream-power approach and the χ method". Earth Surface Dynamics Discussions 3, nr 3 (17.08.2015): 689–714. http://dx.doi.org/10.5194/esurfd-3-689-2015.
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Abstract. Quantitative tectonic geomorphology hinges on the analysis of longitudinal river profiles. The model behind almost all approaches in this field originates from an empirical relationship between channel slope and catchment size, often substantiated in form of the stream-power model for fluvial incision. A significant methodological progress was recently achieved by introducing the χ transform. It defines a nonlinear length coordinate in such a way that the inherent curvature of river profiles due to the increase of catchment sizes in downstream direction is removed from the analysis. However, the limitation to large catchment sizes inherited from the stream power approach for fluvial incision persists. As a consequence, only a small fraction of all nodes of a DEM can be used for the analysis. In this study we present and discuss some empirically derived extensions of the stream power law towards small catchment sizes in order to overcome this limitation. Beyond this, we introduce a simple method for estimating the adjustable parameters in the original χ method as well as in our extended approaches. As a main result, an approach originally suggested for debris flow channels seems to be the best approximation if both large and small catchment sizes are included in the same analysis.
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Clarke, C. J., R. J. George, R. W. Bell i R. J. Hobbs. "Major faults and the development of dryland salinity in the western wheatbelt of Western Australia". Hydrology and Earth System Sciences 2, nr 1 (31.03.1998): 77–91. http://dx.doi.org/10.5194/hess-2-77-1998.
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Abstract. Dryland salinity poses a major threat to agricultural production in the wheatbelt of Western Australia and much time and effort is expended on understanding the mechanisms which cause it and on developing techniques to halt or reverse its development. Whilst the location of much dryland salinity can be explained by its topographic position, a significant proportion of it cannot. This study investigated the hypothesis that major faults in the Yilgarn Craton represented in aeromagnetic data by intense curvilinear lows explained the location of areas of dryland salinity not explained by topography. Moreover, the causal mechanisms that might underpin a spatial relationship between major faults and dryland salinity were sought. In one fourth order catchment, nearly 85% of the salinity that was not explained topographically was within 2km of the centre line of a major fault, the remaining 15% being in the other 12km of the catchment. Three groups of similar third order catchments in the western wheatbelt of Western Australia were also investigated; in each case the catchment that was underlain by a major fault had dryland salinity an order of magnitude more than the unfaulted catchment(s). This evidence demonstrates a strong spatial association between major faults and the development of dryland salinity. Other evidence suggests that the underlying mechanism is hydraulic conductivity 5.2 to 2.9 times higher inside the fault zone compared to outside it and shows that geomorphology, salt store, regolith thickness, and degree of clearing are not the underlying mechanisms. In one of the groups of catchments, it has been calculated that an amount of recharge, significant in relation to recharge from rainfall, was entering from an adjacent catchment along a major fault. The paper concludes that geological features such as major faults affect the development of dryland salinity in the wheatbelt of Western Australia because of permeability differences in the regolith and therefore computer models of salinity risk need to take these differences into account. Techniques need to be developed to map, quickly and relatively cheaply, the geology-related permeability differences over wide areas of the landscape.
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Howcroft, William, Ian Cartwright i Uwe Morgenstern. "Mean transit times in headwater catchments: insights from the Otway Ranges, Australia". Hydrology and Earth System Sciences 22, nr 1 (25.01.2018): 635–53. http://dx.doi.org/10.5194/hess-22-635-2018.
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Abstract. Understanding the timescales of water flow through catchments and the sources of stream water at different flow conditions is critical for understanding catchment behaviour and managing water resources. Here, tritium (3H) activities, major ion geochemistry and streamflow data were used in conjunction with lumped parameter models (LPMs) to investigate mean transit times (MTTs) and the stores of water in six headwater catchments in the Otway Ranges of southeastern Australia. 3H activities of stream water ranged from 0.20 to 2.14 TU, which are significantly lower than the annual average 3H activity of modern local rainfall, which is between 2.4 and 3.2 TU. The 3H activities of the stream water are lowest during low summer flows and increase with increasing streamflow. The concentrations of most major ions vary little with streamflow, which together with the low 3H activities imply that there is no significant direct input of recent rainfall at the streamflows sampled in this study. Instead, shallow younger water stores in the soils and regolith are most likely mobilised during the wetter months. MTTs vary from approximately 7 to 230 years. Despite uncertainties of several years in the MTTs that arise from having to assume an appropriate LPM, macroscopic mixing, and uncertainties in the 3H activities of rainfall, the conclusion that they range from years to decades is robust. Additionally, the relative differences in MTTs at different streamflows in the same catchment are estimated with more certainty. The MTTs in these and similar headwater catchments in southeastern Australia are longer than in many catchments globally. These differences may reflect the relatively low rainfall and high evapotranspiration rates in southeastern Australia compared with headwater catchments elsewhere. The long MTTs imply that there is a long-lived store of water in these catchments that can sustain the streams over drought periods lasting several years. However, the catchments are likely to be vulnerable to decadal changes in land use or climate. Additionally, there may be considerable delay in contaminants reaching the stream. An increase in nitrate and sulfate concentrations in several catchments at high streamflows may represent the input of contaminants through the shallow groundwater that contributes to streamflow during the wetter months. Poor correlations between 3H activities and catchment area, drainage density, land use, and average slope imply that the MTTs are not controlled by a single parameter but a variety of factors, including catchment geomorphology and the hydraulic properties of the soils and aquifers.
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Hall, M. J., A. F. Zaki i M. M. A. Shahin. "Regional analysis using the Geomorphoclimatic Instantaneous Unit Hydrograph". Hydrology and Earth System Sciences 5, nr 1 (31.03.2001): 93–102. http://dx.doi.org/10.5194/hess-5-93-2001.
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Abstract. The construction of design flood hydrographs for ungauged drainage areas has traditionally been approached by regionalisation, i.e. the transfer of information from the gauged to the ungauged catchments in a region. Such approaches invariably depend upon the use of multiple linear regression analysis to relate unit hydrograph parameters to catchment characteristics and generalised rainfall statistics. The concept of the geomorphological instantaneous unit hydrograph (GIUH), in relating the shape and scale of the catchment transfer function to stream network topology and channel characteristics, offers an alternative methodology. GIUH derivation depends upon a series of assumptions, including that of estimating a "characteristic velocity"; these continue to attract attention and debate. However, if this velocity is expressed in terms of the kinematic wave approximation, the peak and time-to-peak of the IUH may be expressed in terms of a group of catchment and channel characteristics and the intensity of rainfall excess, giving the so-called geomorphoclimatic IUH (GCIUH). Previous studies involving the GCIUH have developed a single IUH relating to the total duration of rainfall excess. In this study, the rainfall excess duration was divided into several (equal) time increments, with separate IUHs being generated for each interval. This quasi-linear approach was applied to 105 storm events from nine catchments in the south-west of England, ranging in size from 6 to 420 (km)2 . The results showed that, providing the time interval chosen is fine enough to capture the shape of the runoff hydrographs, a comparable level of goodness-of-fit can be obtained for catchments covering a range of about 1:75 in area. The modified GCIUH approach as described is therefore recommended for further investigation and intercomparison with regression-based regionalisation methods. Keywords: floods; geomorphology; rainfall-runoff modelling
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Zaineldeen, Usama, i Adnan Aish. "Geology, geomorphology and hydrology of the Wadi Gaza catchment, Gaza Strip, Palestine". Journal of African Earth Sciences 76 (listopad 2012): 1–7. http://dx.doi.org/10.1016/j.jafrearsci.2012.07.005.
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El Bastawesy, Mohammed, Omnia El Saadawy, Abotalib Z. Abotalib, Abdullah Othman, Maysa Taha i Ahmed Gaber. "Examining the Impact of Different DEM Sources and Geomorphology on Flash Flood Analysis in Hyper-Arid Deserts". ISPRS International Journal of Geo-Information 10, nr 7 (24.06.2021): 431. http://dx.doi.org/10.3390/ijgi10070431.
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Digital elevation models (DEMs) are the cornerstone for hydrological and geomorphological modeling. Herein, two Nile-tributary catchments (Wadi Al Rishrash and Wadi Atfeh) in Egypt are selected to examine the contribution of different DEMs to the accuracy of hydrological and geomorphological analyses in the hyper-arid Sahara. DEMs sources include: Advanced Land Observing Satellite-1 (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) (12.5 m resolution), ALOS World 3D with 30 m resolution (AW3D30), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER DEM with 30 m resolution) and the Shuttle Radar Topography Mission (SRTM with 30 and 90 m resolution), in addition to topographic map-derived DEM (90 m resolution). Using a hypothetical uniformly-distributed 10 mm rainfall event, the estimated parameters, including: flow duration, time to peak and peak discharge rates, are almost similar for the different DEMs and thus technical aspects related to sources and resolutions of the datasets impose insignificant control on quantitative flash-flood analyses. Conversely, variations in geological and geomorphological characteristics of the catchments show more significant control on the hydrograph magnitudes as indicated by the different parameters of the two catchments. These findings indicate that understanding the geological and hydrological evolution of the catchment is essential for integrated management strategies of floods especially in the Saharan–Arabian deserts and in similar conditions of hyper-aridity and scarce in situ data worldwide.
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Wagner, Thomas, Roswitha Pleschberger, Simon Kainz, Markus Ribis, Andreas Kellerer-Pirklbauer, Karl Krainer, Rudolf Philippitsch i Gerfried Winkler. "The first consistent inventory of rock glaciers and their hydrological catchments of the Austrian Alps". Austrian Journal of Earth Sciences 113, nr 1 (1.01.2020): 1–23. http://dx.doi.org/10.17738/ajes.2020.0001.
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AbstractA first consistent and homogenized polygon-based inventory of rock glaciers of the Austrian Alps is presented. Compiling previous inventories and updating them by using digital elevation models (1 m grid resolution) derived from airborne laser scanning yield a dataset of 5769 rock glaciers in a ca. 48400 km2 large area. A consistent methodological approach for assigning attributes, stored in a detailed attribute table, was developed and applied here to improve comparability and reproducibility. The majority (60 %) of the studied landforms is considered to be relict (no permafrost); the remaining 40 % may still contain permafrost ice and are thus classified as intact. Rock glaciers range in elevation from 476 to 3312 m a.s.l. and cover a total area of 303 km2. The distribution of rock glaciers is mainly related to the topography of the Austrian Alps and related effects such as past glaciation history.In addition, a comprehensive analysis of the hydrological catchment areas of all individual rock glaciers was carried out. A hydrological catchment analysis in rock glacier areas is of great interest for sustainable water management issues in alpine catchments as these landforms represent shallow aquifer systems with a relatively high storage and thus buffer capability, especially in crystalline bedrock areas. A total area of almost 1280 km2 is drained through rock glaciers.The presented rock glacier and rock glacier catchment inventories provide an important basis for further research, particularly for a better understanding of the hydrogeology and geomorphology of alpine catchments and their potential alteration in the light of climate change, but also in terms of paleoglaciation and deglaciation in the Alpine Lateglacial to Holocene period. As such, the inventories are seen as an important base to stimulate further research.
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Hergarten, S., J. Robl i K. Stüwe. "Tectonic geomorphology at small catchment sizes – extensions of the stream-power approach and the <i>χ</i> method". Earth Surface Dynamics 4, nr 1 (15.01.2016): 1–9. http://dx.doi.org/10.5194/esurf-4-1-2016.
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Abstract. Quantitative tectonic geomorphology hinges on the analysis of longitudinal river profiles. The model behind almost all approaches in this field originates from an empirical relationship between channel slope and catchment size, often substantiated in the form of the stream-power model for fluvial incision. Significant methodological progress was recently achieved by introducing the χ transform. It defines a nonlinear length coordinate in such a way that the inherent curvature of river profiles due to the increase of catchment sizes in the downstream direction is removed from the analysis. However, the limitation to large catchment sizes inherited from the stream-power approach for fluvial incision persists. As a consequence, only a small fraction of all nodes of a digital elevation model (DEM) can be used for the analysis. In this study we present and discuss some empirically derived extensions of the stream power law towards small catchment sizes in order to overcome this limitation. Beyond this, we introduce a simple method for estimating the adjustable parameters in the original χ method as well as in our extended approaches. As a main result, an approach originally suggested for debris flow channels seems to be the best approximation if both large and small catchment sizes are included in the same analysis.
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Vyšná, V., F. Dyer, W. Maher i R. Norris. "Organic carbon reservoirs in five small rivers across a land-use gradient". Marine and Freshwater Research 66, nr 3 (2015): 233. http://dx.doi.org/10.1071/mf13142.
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Organic carbon (OC) inputs, stores and processing underpin river functioning. We examined patterns in OC reservoirs (total organic carbon, TOC), suspended OC, drifting coarse particulate OC (drift OC), organic debris and the biomass of in-stream primary producers in five geographically proximate small rivers in south-eastern Australia during base-flow conditions. Despite differences in the extent of land-use conversion (native forest-to-pasture) and geomorphology among all sites, we found greater within-river than ‘within-land-use’ similarities in OC reservoirs. Our predictions regarding the relationships between distant v. proximate land-use and the OC reservoirs were mostly not confirmed. Riparian canopy cover was correlated with the mass of organic debris but not with other OC reservoirs. Our predictions regarding longitudinal patterns in rivers were also not confirmed. Rivers draining catchments with conservation land-use only did not show consistent patterns that were different from rivers draining a combination of conservation and grazing land. Variability in the extent of land converted to other uses was not necessarily associated with greater longitudinal variability in OC reservoirs. Our results suggest: (1) strong within-catchment controls of TOC concentration that are maintained despite a certain level of catchment impairment and (2) between-river differences in TOC at a local scale as great as continental scale differences.
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Murray, Hannah, i Alastair HF Robertson. "Pliocene–Pleistocene sedimentary and geomorphologic development of the Vasilikos river catchment, S Cyprus, in relation to uplift of the Troodos ophiolite and climate-related changes". Geological Magazine 157, nr 4 (25.10.2019): 573–602. http://dx.doi.org/10.1017/s0016756819001134.
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AbstractThe Pleistocene development of the Vasilikos River exemplifies the interaction of focused, tectonically induced surface uplift and climate-influenced changes. The resulting sediments are well exposed in Vasilikos Quarry and in the main river catchment further east. An important erosional surface incises the highest-level (oldest) fluvial conglomerates, down into Late Pliocene – Early Pleistocene open-marine mudrocks (Nicosia Formation), allowing integration with the circum-Cyprus sedimentary–geomorphic development (F1–F4 stages). To determine where the quarry deposits lie in relation to the Vasilikos river catchment, the fluvial deposits were mapped and valley profiles were constructed, revealing four main episodes, each associated with incision and distinctive fluvial deposition. Source lithology strongly influenced channel morphology, infill and adjacent slope-sediment (colluvium) composition. Palaeosols, particularly red-brown terra rossa, developed on abandoned fluvial terraces and adjacent hillslopes, especially overlying F3 surfaces. The combined evidence allows close correlation of the Vasilikos river and quarry deposits. Relatively coarse (chalky conglomerate/breccia) and fine-grained colluvium (calcareous silt – Cyprus harvara) developed especially on lower hillslopes following incision (mainly above F2 and F3 surfaces). Based on regional comparisons, overall sediment aggregation ended during the Early Pleistocene. The F1–F2 surfaces and deposits are inferred to be Middle Pleistocene, the F3 ones later Middle Pleistocene and the F4 ones near the Middle–Late Pleistocene boundary. Geomorphology and deposition were tectonically forced during strong, focused Early–Middle Pleistocene surface uplift. Coarse clastic ruff-off and palaeosol development (terra rossa) and related sediment aggradation are inferred to have increased during warm, humid periods. Late Pleistocene geomorphology and deposition were more influenced by climatic change, with semi-perennial streamflow, rapid sediment aggradation and palaeosol (terra rossa) development during warm, humid periods (interglacials). Cooler (glacial) periods enhanced fluvial-incision, sediment-bypassing and hillslope colluvial processes (e.g. frost shattering, downslope creep and mass flow) when sediment transport (bypassing) exceeded sediment supply. Neotectonic faulting affected the catchment but did not greatly affect geomorphology or sediment supply. Although climate / climate change (and eustatic sea-level change) had an important influence, tectonics is interpreted as the fundamental driver of geomorphological development and fluvial sedimentation, with implications for other areas, regionally to globally.
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Oppel, Henning, i Andreas Schumann. "A method to employ the spatial organization of catchments into semi-distributed rainfall–runoff models". Hydrology and Earth System Sciences 21, nr 8 (30.08.2017): 4259–82. http://dx.doi.org/10.5194/hess-21-4259-2017.
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Abstract. A distributed or semi-distributed deterministic hydrological model should consider the hydrologically most relevant catchment characteristics. These are heterogeneously distributed within a watershed but often interrelated and subject to a certain spatial organization which results in archetypes of combined characteristics. In order to reproduce the natural rainfall–runoff response the reduction of variance of catchment properties as well as the incorporation of the spatial organization of the catchment are desirable. In this study the width-function approach is utilized as a basic characteristic to analyse the succession of catchment characteristics. By applying this technique we were able to assess the context of catchment properties like soil or topology along the streamflow length and the network geomorphology, giving indications of the spatial organization of a catchment. Moreover, this information and this technique have been implemented in an algorithm for automated sub-basin ascertainment, which included the definition of zones within the newly defined sub-basins. The objective was to provide sub-basins that were less heterogeneous than common separation schemes. The algorithm was applied to two parameters characterizing the topology and soil of four mid-European watersheds. Resulting partitions indicated a wide range of applicability for the method and the algorithm. Additionally, the intersection of derived zones for different catchment characteristics could give insights into sub-basin similarities. Finally, a HBV96 case study demonstrated the potential benefits of modelling with the new subdivision technique.
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Clausen, B. "Discharge Data Collection and Analysis Strategies in Low Flow Studies". Hydrology Research 26, nr 3 (1.06.1995): 191–204. http://dx.doi.org/10.2166/nh.1995.0011.
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The objective of this paper is to determine the most appropriate data collection strategy and analysis techniques which should be used to assess the low flow regime of a catchment. The data used were: a) synchronous discharge measurements during low flow periods, and b) continuous daily flow records. The analyses based on both types of data were able to distinguish different low flow regimes within a 114 km2 Danish catchment. Despite the limited spatial variation in climate and geomorphology there was a high spatial variability in low flows caused by differences in the lithology of sediments. This demonstrates the difficulties in using simple indices of catchment geology in regional low flow estimation. The results highlight the benefits of using synchronous discharge measurements, both for estimating low flows at ungauged sites, and for understanding groundwater flow paths. Analyses of daily flow records from six gauging stations in the catchment showed that a baseflow index was more useful than the flow duration curve for classifying low flow regimes when only short records were available. The paper illustrates the importance of estimating the uncertainty of discharge measurements when interpreting low flow data.
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Xu, Xiangyu, Hanbo Yang, Dawen Yang i Huan Ma. "Assessing the impacts of climate variability and human activities on annual runoff in the Luan River basin, China". Hydrology Research 44, nr 5 (9.05.2013): 940–52. http://dx.doi.org/10.2166/nh.2013.144.
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Regional hydrological processes have been greatly influenced by human activities and climate variability. The inflow of Panjiakou Reservoir, which is the largest reservoir located on the Luan River, has shown a significant decreasing trend over the past 50 years. A large-scale hydrological model, namely the geomorphology-based hydrological model (GBHM), and a climate elasticity model were applied to perform quantitative attributing analysis of runoff change in the study catchment. Annual runoff decreased by 19.5 mm from 65.7 mm in the period 1956–1979 to 46.2 mm in the period 1980–2005. Annual direct water intake increased by 22.5 mm from 3.6 to 26.1 mm. Climate impact was accountable for the runoff increase of 8.8 and 9.2 mm simulated by GBHM and the climate elasticity model, respectively. Impacts of land use and vegetation change accounted for the runoff decrease of 2.5 mm. Change of precipitation and vegetation cover contributed to annual runoff change for the upper catchment (grassland-dominated). Change of antecedent precipitation (a proxy of soil moisture) also contributed to annual runoff change for the lower catchment (forest-dominated) and the whole catchment (mixture vegetation).
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Estrany, Joan, i Miquel Grimalt. "Catchment controls and human disturbances on the geomorphology of small Mediterranean estuarine systems". Estuarine, Coastal and Shelf Science 150 (październik 2014): 230–41. http://dx.doi.org/10.1016/j.ecss.2014.03.021.
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Hancock, G. R. "The impact of depression removal on catchment geomorphology, soil erosion and landscape evolution". Earth Surface Processes and Landforms 33, nr 3 (2008): 459–74. http://dx.doi.org/10.1002/esp.1598.
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Prasad, Ramashray, i Jitendra Rishideo. "GEOMORPHOLOGY AND ITS DIFFERENT PARAMETERS IN THE FLOOD PRONE LOWER GANDAK PAIN". International Journal of Advanced Research 9, nr 10 (31.10.2021): 74–85. http://dx.doi.org/10.21474/ijar01/13519.
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The physical appearance of any area is the outcome of geomorphological interactions between endogenic and exogenic processes. Endogenic processes are very slow while the exogenic are quite obviously observable operating at or from above the surface of the area. They may be included like - wind, fluvial, glacio-fluvial, glacier, permafrost, karst etc. They sculpture the concerned area and people use the same for their own needs. Land use may be seen in two ways - natural or human induced use of land. The Lower Gandak Plain is characterized by flooding in the monsoon period when torrential rain associated with glacier melt water occupy the low lying area in the region. But this huge amount of water is brought by numerous tributaries of Gandak from upper Himalayan catchment. Therefore, enormous water from Himalayan catchment is to be drained through the Lower Gandak Plain. The Gandak flood plain is highly populated and anthropogenic activities are prominent. So, most of the areas have human sign and less as natural. Flooding is, therefore, more due to anthropogenic factors. Hence, an attempt has been made here to (i) evaluate the geomorphological characteristics, (ii) elaborate the flood plain forming processes on the basis of planforms, and (iii) explain various geomorphological parameters in the Lower Gandak Plain. This study is expected to help in systematic and integrated plan preparation for overall development of the Lower Gandak Plain on the basis of detail characteristics of the area explained.
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Keesstra, S. D., E. Kondrlova, A. Czajka, M. Seeger i J. Maroulis. "Assessing riparian zone impacts on water and sediment movement: a new approach". Netherlands Journal of Geosciences - Geologie en Mijnbouw 91, nr 1-2 (wrzesień 2012): 245–55. http://dx.doi.org/10.1017/s0016774600001633.
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AbstractThe state of river channels and their riparian zones in terms of geomorphology and vegetation has a significant effect on water and sediment transport in headwater catchments. High roughness in natural rivers due to vegetation and geomorphological attributes generate drag on flowing water. This drag will slow water discharge, which in turn influences the sediment dynamics of the flow. The impacts of changes in the management of rivers and their riparian zone (either by catchment managers or river restoration plans) impacts both up- as well as downstream reaches, and should be assessed holistically prior to the implementation of these plans.To assess the river's current state as well as any possible changes in geomorphology and vegetation in and around the river, effective approaches to characterise the river are needed. In this paper, we present a practical approach for making detailed surveys of relevant river attributes. This methodology has the benefit of being both detailed – describing river depth, width, channel morphology, erosive features and vegetation types – but also being practical in terms of time management. This is accomplished by identifying and describing characteristic benchmark reaches (typical sites) in detail against which the remainder of the river course can be rated. Using this method, a large river stretch can be assessed in a relatively short period while still retrieving high quality data for the total river course. In this way, models with high data requirements for assessing the condition of a river course, can be parameterised without major investments on field surveys.In a small headwater catchment (23 km2) in southwestern Poland, this field methodology was used to retrieve data to run an existing model (HEC-GeoRAS) which can assess the impact of changes in the riparian and channel vegetation and channel management on sedimentation processes and stream flow velocity. This model determines the impact of channel morphology and in-channel and riparian vegetation on stream flow and sediment transport. Using four return periods of flooding (2, 10, 20 and 100 years), two opposing channel management / morphology scenarios were run; a natural channel and a fully regulated channel. The modelling results show an increase in the effect of riparian vegetation / geomorphology with an increase in return period of the modeled peak discharge. More natural channel form and increased roughness reduces the stream flow velocity due to increasing drag from flow obstructions (vegetation and channel morphological features). The higher the flood water stage, the greater the drag due to vegetation on the floodplains of natural river reaches compared to channelised sections. Slower flow rates have an impact on sediment mobilisation and transport in the river.
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Morón, Sara, Kathryn Amos i Sandra Mann. "Fluvial reservoirs in dryland endorheic basins: the Lake Eyre Basin as a world-class modern analogue". APPEA Journal 54, nr 1 (2014): 119. http://dx.doi.org/10.1071/aj13014.
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Intracratonic dryland basins have been common throughout geological time and significant hydrocarbon reservoirs are contained in these basins. Based on a literature compilation of fluvial dryland reservoirs, the authors demonstrate the need for new modern analogue data from dryland fluvial systems, and present new field data from the Neales River, in the Lake Eyre catchment. The selected study reach has a complex planform, with a downstream transition from single channel to anabranching. Results of the observations of the channel bed grain size, the geomorphology and the channel geometry (width and depth) allow the authors to infer that the channel bed grain size is more strongly related to planform geomorphology than the channel geometry (width to depth ratios). Based on the grain size and channel geometry data the authors present, the authors conclude that the planform geomorphology exerts a greater control on channel bed material size than channel geometry. This interpretation is based on the analysis of satellite imagery, topographic survey data and grain size descriptions. In this paper, the authors provide channel geometry data and grain size data that will improve understanding of dryland fluvial sedimentology. The authors hope this contributes to enhancing hydrocarbon exploration and production in petroleum reservoirs developed in dryland fluvial settings.
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Hayes, Miles O., i Todd M. Montello. "THE DEVELOPMENT OF POTENTIAL PROTECTION STRATEGIES FOR TIDAL INLETS". International Oil Spill Conference Proceedings 1995, nr 1 (1.02.1995): 1012–13. http://dx.doi.org/10.7901/2169-3358-1995-1-1012.
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ABSTRACT Protection of coastal environments on the landward sides of tidal inlets requires effective systems of booms within the inlets. Protection strategies have been developed for more than 200 inlets on the coasts of California and Florida. They call for the use of deflection booming to divert oil to low-current zones, where it can be collected with skimmers, or to catchment areas along the shore, where it can be cleaned up. The strategies are based on an understanding of the hydrodynamics and geomorphology of the tidal inlets.
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Sear, David, Malcolm Newson, Christopher Hill, Jo Old i Julia Branson. "A method for applying fluvial geomorphology in support of catchment-scale river restoration planning". Aquatic Conservation: Marine and Freshwater Ecosystems 19, nr 5 (lipiec 2009): 506–19. http://dx.doi.org/10.1002/aqc.1022.
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Webb, T. H., B. D. Fahey, K. M. Giddens, S. Harris, C. C. Pruden i J. S. Whitton. "Soil-landscape and soil-hydrological relationships in the Glendhu Experimental Catchments, East Otago Uplands, New Zealand". Soil Research 37, nr 4 (1999): 761. http://dx.doi.org/10.1071/sr98102.
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Soil-landscape relationships were investigated in a first-order catchment and a fifth-order catchment of the Waipori River. The soils are formed mainly from loess and loess−colluvium derived fromschist, with limited inclusions of rock material from under lying schist bedrock. Five soil series are identified primarilyon the basis of differences in soil drainage. Occurrence of soil series within the landscape is related to a combination of aspect and slope angle while the depth of regolith is related to a combination of landform element and slope angle. Five soil profiles within a first-order catchment were analysed for chemical, mineralogical, and hydrological properties. Allsoils are acidic, strongly leached, and moderately weathered. Pedogenesis and geomorphology are discussed in relation to glacial history, climate, and vegetation. Evidence is presented to indicate that the change from forest to tussock grassland vegetation, 700−1000 years ago, has had a major impact on the development of a perch-gley profile morphology. Permeable conditions are largely confined to the upper 0·10−0·15 m depth and to underlying very stony horizons below 0·50 m depth. All profiles have one or more horizons with very slow permeability. Under high or prolonged rainfall conditions, water will perch above slowly permeable horizons and flow laterally within more permeable surface horizons. This conclusion is in agreement with previous water-flow measurements in the catchment.
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Li, Min, Xin Yang, Jiaming Na, Kai Liu, Yini Jia i Liyang Xiong. "Regional topographic classification in the North Shaanxi Loess Plateau based on catchment boundary profiles". Progress in Physical Geography: Earth and Environment 41, nr 3 (23.05.2017): 302–24. http://dx.doi.org/10.1177/0309133317706356.
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Topographic classification and mapping are fundamental topics in geomorphology and have many promising applications. This study aimed to achieve landform classification using the catchment boundary profile (CBP) in the area of the North Shaanxi Province. CBPs were extracted, and seven indices were proposed and calculated to describe the profile features. Spatial maps of these indices were generated by interpolating 81 sample areas in the North Shaanxi Province of China. Finally, a topographic regional map was generated through multi-resolution segmentation after integrating the spatial maps of the seven indices. Results showed that the CBP indices were typical and representative to describe the terrain characteristics in the North Shaanxi Province and revealed their diverse spatial patterns. The investigated area was classified into 14 topographic units. The requirements of maximizing internal homogeneity while minimizing external homogeneity in terms of morphological characteristics were satisfied through the analysis of the terrain texture, topographic features, and land surface parameters. A comparison with the reference map showed that the regional classification differed from the geomorphologic map, given the different classification systems. However, the regional classification provided new knowledge of topographic features and spatial patterns in the macro scale. A comparison with other classification method indicated the advantage of the CBP-based method, which could distinguish the landforms of loess tableland, loess ridge, and loess hill that are the typical characteristics of loess landforms. The sensitivity analysis revealed that the differences in CBP indices, except for roughness and fractal dimension (FD) from different landforms, would increase with the digital elevation model (DEM) resolution becoming coarser, which indicates that the CBP-based method could be applied on a coarser resolution DEM if the differences of roughness and FD from different landforms could be identified at this coarse DEM level.
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Müller, Tom, Stuart N. Lane i Bettina Schaefli. "Towards a hydrogeomorphological understanding of proglacial catchments: an assessment of groundwater storage and release in an Alpine catchment". Hydrology and Earth System Sciences 26, nr 23 (2.12.2022): 6029–54. http://dx.doi.org/10.5194/hess-26-6029-2022.
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Abstract. Proglacial margins form when glaciers retreat and create zones with distinctive ecological, geomorphological and hydrological properties in Alpine environments. There is extensive literature on the geomorphology and sediment transport in such areas as well as on glacial hydrology, but there is much less research into the specific hydrological behavior of the landforms that develop after glacier retreat in and close to proglacial margins. Recent reviews have highlighted the presence of groundwater stores even in such rapidly draining environments. Here, we describe the hydrological functioning of different superficial landforms within and around the proglacial margin of the Otemma glacier, a temperate Alpine glacier in the Swiss Alps; we characterize the timing and amount of the transmission of different water sources (rain, snowmelt, ice melt) to the landforms and between them, and we compare the relationship between these processes and the catchment-scale discharge. The latter is based upon a recession-analysis-based framework. In quantifying the relative groundwater storage volumes of different superficial landforms, we show that steep zones only store water on the timescale of days, while flatter areas maintain baseflow on the order of several weeks. These landforms themselves fail to explain the catchment-scale recession patterns; our results point towards the presence of an unidentified storage compartment on the order of 40 mm, which releases water during the cold months. We suggest attributing this missing storage to deeper bedrock flowpaths. Finally, the key insights gained here into the interplay of different landforms as well as the proposed analysis framework are readily transferable to other similar proglacial margins and should contribute to a better understanding of the future hydrogeological behavior of such catchments.
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Nosrati, Kazem, Gregor Laaha, Seyed Ali Sharifnia i Mojtaba Rahimi. "Regional low flow analysis in Sefidrood Drainage Basin, Iran using principal component regression". Hydrology Research 46, nr 1 (22.01.2014): 121–35. http://dx.doi.org/10.2166/nh.2014.087.
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Knowledge of low streamflow statistics is necessary for effective water management in regions prone to extreme hydrologic events such as Iran. This study employs a data set of 23 river flow time series from Sefidrood Drainage Basin, Iran, to examine regional hydrological drought based on the low flow index 7Q10. Hierarchical agglomerative cluster analysis was used to divide the 23 gauging stations into two homogeneous drought regions based on the similarity of the binary drought series. 7Q10 was determined using log-Pearson type-III and 2-parameter log-normal distributions selected as the best regional probability distribution functions in homogeneous drought region 1 and 2, respectively. The 7Q10 was related to principal components of catchment characteristics in each homogeneous drought region separately using backward stepwise regression. The resulting regression equations exhibit a coefficient of determination of 69 and 89%, respectively. The regression parameters are linked to a size factor related to catchment area, an elevation factor which is independent of catchment area, and geological formation variables, which can therefore be interpreted as important controls of low flow generation processes in the study area. The equations developed here are expected to provide robust estimates of 7Q10 values for watersheds in areas of similar geomorphology, geology and climate.
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Kováč, Michal, Jozef Hók, Jozef Minár, Rastislav Vojtko, Miroslav Bielik, Radovan Pipík, Miloš Rakús, Ján Kráľ, Martin Šujan i Silvia Králiková. "Neogene and Quaternary development of the Turiec Basin and landscape in its catchment: a tentative mass balance model". Geologica Carpathica 62, nr 4 (1.08.2011): 361–79. http://dx.doi.org/10.2478/v10096-011-0027-6.
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Neogene and Quaternary development of the Turiec Basin and landscape in its catchment: a tentative mass balance modelThe development of the Turiec Basin and landscape evolution in its catchment has been reconstructed by methods of geological research (structural geology, sedimentology, paleoecology, and geochronological data) as well as by geophysics and geomorphology. The basin and its surrounding mountains were a subject of a mass balance study during periods of tectonic activity, accompanied by considerable altitudinal differentiation of relief and also during quiet periods, characterized by a development of planation surfaces in the mountains. The coarse clastic alluvial fans deposited beneath the offshore pelitic sediments document the rapid Middle Miocene uplift of mountains on the margin of the Turiec Basin. The Late Miocene finegrained sedimentation represents the main fill of this basin and its origin was associated with the formation of planation surfaces in the surrounding mountains. The rapid uplift of the western and northern parts of the catchment area during the latest Miocene and Early Pliocene times further generated the deposition of coarse-grained alluvial fans. The Late Pliocene basin inversion, due to uplift of the whole Western Carpathians mountain chain, was associated with the formation of the Early Quaternary pediment and ultimately with the formation of the Turiec river terrace systems.
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Harvey, Gemma L., Tom P. Moorhouse, Nicholas J. Clifford, Alexander J. Henshaw, Matthew F. Johnson, David W. Macdonald, Ian Reid i Stephen P. Rice. "Evaluating the role of invasive aquatic species as drivers of fine sediment-related river management problems: The case of the signal crayfish (Pacifastacus leniusculus)". Progress in Physical Geography: Earth and Environment 35, nr 4 (10.05.2011): 517–33. http://dx.doi.org/10.1177/0309133311409092.
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Sediment quantity and quality are key considerations in the sustainable management of fluvial systems. Increasing attention is being paid to the role of aquatic biota as geomorphic agents, capable of altering the composition, mobilization and transport of fluvial sediments at various spatiotemporal scales. In this paper invasive species are presented as a special case since: (1) populations may not be constrained by factors characteristic of their native habitats; and (2) they represent a disturbance to which the system may not be resilient. Discussion is centred on the signal crayfish which has rapidly colonized catchments in Europe and Japan, but the hypotheses and models presented provide a framework applicable to other invasive species. This paper explores the mechanisms by which signal crayfish may influence sediment dynamics from the patch scale to the catchment scale. There is potential for signal crayfish to impact significantly on river sediments and morphology as a function of their interactions with river bed and bank material, and with other aquatic organisms, combined with their large body size and aggressive nature, their presence in very high densities, and the lack of effective mitigation strategies. Potential catchment-scale management issues arising from these factors include habitat degradation, mobilization of sediment-associated nutrients and contaminants, and sediment-related flood risks. Further interdisciplinary research is required at the interface between freshwater ecology, fluvial geomorphology and hydraulics, in order to quantify the significance and extent of these impacts. The paper points to the key research agendas that may now emerge.
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Raghuram, P., T. Rambabu, P. A.R.K Raju i P. Sankara Pitchaiah. "Geological and Geomorphological Evaluation of Kolleru-Upputeru catchment using Geospatial Technologies". International Journal of Engineering & Technology 7, nr 3.31 (24.08.2018): 75. http://dx.doi.org/10.14419/ijet.v7i3.31.18205.
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Kolleru Lake is a unique world famous wetland ecosystem. It is one of the prime coastal ecosystems in India and regarded as Ramsar site. It is located in the coastal tracts of Krishna and West Godavari districts of Andhra Pradesh. Overexploitation and mismanagement of land and water resources are exerting detrimental impact on the lake environment. The striking manifestation of this phenomenon is seen various kinds of problems such as shrinkage in Lake area, floods in foreshore area, pollution and siltation of lake, sea water intrusion, land degradation etc. The challenge therefore is, to arrest the degradational processes and restore the lake eco-system. The generation and evaluation spatial information on the terrain conditions that include Tectonic frame work, Lithology, Structure and Geomorphology of the area using geospatial technologies carried out in the present study forms an important component to address various issues in respect of land and water resources. Thus, the spatial database facilitates to formulate a scientific plan for the conservation, restoration and management of Kolleru lake ecosystem.
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Quesada-Román, Adolfo, Jose Pablo Castro-Chacón i Sergio Feoli Boraschi. "Geomorphology, land use, and environmental impacts in a densely populated urban catchment of Costa Rica". Journal of South American Earth Sciences 112 (grudzień 2021): 103560. http://dx.doi.org/10.1016/j.jsames.2021.103560.
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Park, Jae Beom, Doo Ki Kang i Hyun Suk Shin. "A Urban Catchment Runoff Analysis Using Geomorphology-Climatic Instantaneous Unit Hydrograph Based Kinematic Wave Theory". Journal of Korean Society of Hazard Mitigation 13, nr 2 (30.04.2013): 319–26. http://dx.doi.org/10.9798/kosham.2013.13.2.319.
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Brierley, Gary J., Tim Cohen, Kirstie Fryirs i Andrew Brooks. "Post-European changes to the fluvial geomorphology of Bega catchment, Australia: implications for river ecology". Freshwater Biology 41, nr 4 (czerwiec 1999): 839–48. http://dx.doi.org/10.1046/j.1365-2427.1999.00397.x.
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Richardson, Murray, Scott Ketcheson, Peter Whittington i Jonathan Price. "The influences of catchment geomorphology and scale on runoff generation in a northern peatland complex". Hydrological Processes 26, nr 12 (15.06.2012): 1805–17. http://dx.doi.org/10.1002/hyp.9322.
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A .HAMID, KHAZAL, i IBRAHIM KH .GHAZAL. "GEOMORPHOLOGY AND HYDROCHEMISTRY OF THE AREA BETWEEN AL-KHOSAR RIVER CATCHMENT AND BASHIQA ANTICLINE 2011." Journal of University of Anbar for Pure Science 5, nr 1 (1.04.2011): 71–81. http://dx.doi.org/10.37652/juaps.2011.15454.
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Assine, Mario Luis, Eder Renato Merino, Fabiano do Nascimento Pupim, Hudson de Azevedo Macedo i Mauricio Guerreiro Martinho dos Santos. "The Quaternary alluvial systems tract of the Pantanal Basin, Brazil". Brazilian Journal of Geology 45, nr 3 (wrzesień 2015): 475–89. http://dx.doi.org/10.1590/2317-4889201520150014.
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ABSTRACT The Pantanal Basin is an active sedimentary basin in central-west Brazil that consists of a complex alluvial systems tract characterized by the interaction between different river systems developed in one of the largest wetlands in the world. The Paraguay River is the trunk river system that drains the water and part of the sediment load received from areas outside of the basin. Depositional styles vary considerably along the river profiles throughout the basin, with the development of entrenched meandering belts, anastomosing reaches, and floodplain ponds. Paleodrainage patterns are preserved on the surface of abandoned lobes of fluvial fans, which also exhibit many degradational channels. Here, we propose a novel classification scheme according to which the geomorphology, hydrological regime and sedimentary dynamics of these fluvial systems are determined by the geology and geomorphology of the source areas. In this way, the following systems are recognized and described: (I) the Paraguay trunk-river plains; (II) fluvial fans sourced by the tablelands catchment area; (III) fluvial fans sourced by lowlands; and (IV) fluvial interfans. We highlight the importance of considering the influences of source areas when interpreting contrasting styles of fluvial architectures in the rock record.
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Nkatagu, H. H. "The Multivariate Statistical Analysis of Abiotic Parameters of the Lake Tanganyika Sub Catchment". Tanzania Journal of Engineering and Technology 31, nr 2 (31.12.2008): 14–20. http://dx.doi.org/10.52339/tjet.v31i2.426.
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Results from multivariate statistical analysis of abiotic parameters conducted during the dry season at 20accessible sites on 8 rivers, 2 lakes and a dam covering the Lake Tanganyika sub catchment are discussed.Standard methods were used to determine the levels of abiotic parameters from water samples. Physicalparameters including DO, EC, Eh, turbidity, temperature, pH and secchi transparency were measured in situwhile chlorophyll a was determined in the laboratory. Nutrients such as NO3-, SiO2, PO43- and Fe2+weredetermined along with HCO3-. Factor analysis resulted in four factors including increased primaryproductivity, redox conditions, dissolution, and reduction processes. Processes including dissolution,diffusion, adsorption, absorption, nitrification, denitrification, mixing and reduction along with theanthropogenic activities, increased photosynthetic activity of algae and the geomorphology of the ecosystemscontribute to the variation of the abiotic parameters. It is recommended that quantification of river flows,sediment load and nutrient budget at various sampling points be determined seasonally for proper evaluationof the hydrologic and limnological functioning of the ecosystem.
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Nigate, Fenta, Marc Van Camp, Alemu Yenehun, Ashebir Sewale Belay i Kristine Walraevens. "Recharge–Discharge Relations of Groundwater in Volcanic Terrain of Semi-Humid Tropical Highlands of Ethiopia: The Case of Infranz Springs, in the Upper Blue Nile". Water 12, nr 3 (18.03.2020): 853. http://dx.doi.org/10.3390/w12030853.
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The major springs in the Infranz catchment are a significant source of water for Bahir Dar City and nearby villages, while sustaining the Infranz River and the downstream wetlands. The aim of the research was to understand the hydrogeological conditions of these high-discharge springs and the recharge–discharge relations in the Infranz catchment. The Infranz catchment is covered by highly pervious and young quaternary volcanic rocks, consisting of blocky, fractured, and strongly vesicular scoriaceous basalt. At the surface, these rocks crop out as lineaments forming ridges, delimiting closed depressions in which water accumulates during the rainy season without causing surface runoff. Geology and geomorphology thus combine to produce very favorable conditions for groundwater recharge. Three groundwater recharge methods were applied to estimate groundwater recharge and the results were compared. Groundwater recharge was calculated to be 30% to 51% of rainfall. Rapid replenishment raises the groundwater level during the rainfall period, followed by a rapid decline during the dry season. Shallow local flow paths discharge at seasonal springs and streams, while more regional and deeper flow systems downstream sustain the high-discharge springs and perennial Infranz River. The uptake of 75% of spring water for the water supply of Bahir Dar City, local extraction for domestic and small-scale irrigation use from springs, rivers and hand-dug wells, encroaching farming, and overgrazing are exacerbating wetland degradation.
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Wang, Ai, Lihua Tang i Dawen Yang. "Spatial and temporal variability of nitrogen load from catchment and retention along a river network: a case study in the upper Xin'anjiang catchment of China". Hydrology Research 47, nr 4 (31.07.2015): 869–87. http://dx.doi.org/10.2166/nh.2015.055.
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Understanding the spatial and temporal variability of nitrogen load and characteristics of retention along a river network is important for land management and water resources protection. This study employs a geomorphology-based non-point source pollution model (GBNP) to simulate the hillslope hydrological processes and transport of sediment and pollutants in the upper Xin'anjiang (XAJ) catchment. Based on the simulation, the spatial and temporal distribution of total nitrogen (TN) load from hillslopes and retention characteristics along the river network are analyzed. The results indicate that annual TN load ranges from 0.54 ton/km2 to 1.88 ton/km2 and is relatively higher during spring and summer. Average TN load positively correlates with irrigated cropland area (r =0.820) and negatively correlates with forest (r = −0.43). Seasonal TN retention ratios in the river network range from 0% to 81%, and streams of order 1 in the Horton–Strahler system have the highest retention ratio and are followed by orders 2, 3, and 4, which are mainly determined by the river hydraulic properties. Results of scenarios analysis demonstrate that TN retention ratios in the river network increase with TN load from hillslopes, but reach a maximum value rapidly, which indicates the limitation of the self-purification capacity of rivers.
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Berntsson, Annika, Krister N. Jansson, Malin E. Kylander, Francois De Vleeschouwer i Sebastien Bertrand. "Late Holocene high precipitation events recorded in lake sediments and catchment geomorphology, Lake Vuoksjávrátje, NW Sweden". Boreas 44, nr 4 (19.06.2015): 676–92. http://dx.doi.org/10.1111/bor.12127.
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