Geomorphic Units Research Articles

Hydrogeological Mapping and Identification of Groundwater Recharge Potential Zone of Reamal Block Deogarh District, Odisha - A Geospatial Technology Approach

Assessment of potential zone of groundwater recharge is extremely important for the protection of water quality and the management of groundwater systems. Groundwater Potential Zones (GPZ) are demarcated with the help of geospatial techniques. The parameters, considered for identifying the GPZ such as geology, geomorphology, slope, drainage density, lineament density, rainfall, soil maps and LULC are generated using the satellite data and toposheet. Later they are integrated with each other applying weighted overlay in ArcGIS. Suitable ranks are assigned for each category of these parameters. For the various geomorphic units, weight factors are decided based on their capability to store groundwater. This procedure is repeated for all the other layers and resultant layers are reclassified. The groundwater potential zones are classified into three categories like poor, good and excellent. The use of aforesaid methodology is demonstrated in a selected study area in Reamal Block of Deogarh District, Odisha. The thematic layers were first digitized from satellite imagery, supported by ancillary data such as toposheet, finally all thematic layers were integrated using ArcGIS software to identify the groundwater recharge potential zones for the study area and generate a map showing these groundwater recharge potential zones namely ‘poorly suitable’, to ‘most suitable’ on knowledge based weightage factors.

The influence of geomorphic unit spatial distribution on nitrogen retention and removal in a large river

Fluvial geomorphic features drive nutrient dynamics in river systems that have only recently begun to be incorporated into conceptual and numerical models designed to predict nutrient yields and flux. The role of channel geomorphic units (pools, riffles, etc.) and their associated aquatic communities in determining nitrogen retention and removal in aquatic ecosystems is understudied. Here we study the effects of the spatial distribution of geomorphic features on within-channel nitrate dynamics. We developed an agent-based model that simulates biological and hydrological processes involved in nitrate retention and removal occurring in a river segment of the 6th order Cahaba River, AL (USA). We simulated nitrate retention and removal under three scenarios in which the total area of geomorphic units were held constant while their longitudinal distributions were manipulated under low and high nitrate supply levels (relative to biological demand). High nitrate supply simulations suppressed any effect caused by differing longitudinal sequence of geomorphic units/aquatic communities. In contrast, low nitrate supply simulations demonstrated differences in total potential nitrate retention and removal for the study segment based on the spatial distribution of geomorphic units/aquatic communities. Our findings suggest that the spatial arrangement of geomorphic units and their associated aquatic communities can be an important control on nitrogen dynamics in large rivers, demonstrating that fluvial geomorphic features merit consideration when nutrient retention and removal in rivers is examined. Thus, measures of channel geomorphology employed in water quality management, biogeochemical studies, and to evaluate the efficacy of restoration efforts on nutrient levels should be broadened to include characterization of the spatial configuration of geomorphic units and their associated aquatic communities.

Geomorphic evolution of Dehra Dun, NW Himalaya: Tectonics and climatic coupling

The Dehra Dun is a good example of a piggyback basin formed from the growth of the Siwalik hills. Two large rivers, the Ganga and the Yamuna, and their tributaries deposit a significant part of their sediment load in the Dun before they enter the Gangetic plains. This work documents the geomorphic complexities and landform evolution of the Dehra Dun through geomorphic mapping and chronostratigraphic investigation of the incised fan sections. Lesser Himalayan hills, inner and outer dissected hills, isolated hills, proximal fan, distal fan, dip slope unit, floodplains, and terraces are the major geomorphic units identified in the area. Isolated hills of fan material (IHF), proximal fan (PF), and distal fan (DF) are identified as fan surfaces from north to south of the valley. The OSL based chronology of the fan sediments suggests that the IHF is the oldest fan consisting of debris flow deposits with a maximum age of ~43ka coinciding with the precipitation minima. The proximal fan consisting of sheet flow deposits represents the second phase of aggradation between 34 and 21ka caused by shifting of deposition locus downstream triggered by high sediment supply that exceeded the transport capacity. The distal fan was formed by braided river deposits during 20–11ka coinciding with the deglacial period. The IHF, PF and DF surfaces were abandoned by distinct incision phases during ~40–35, ~20–17, and ~11–4ka respectively. A minor phase of terrace deposition in Dehra Dun was documented during 3–2ka. Our results thus show that the evolutionary history of the alluvial fans in Dehra Dun was primarily controlled by climatic forcing with tectonics playing a minimum role in terms of providing accommodation space and sediment production.

Quantitative study on shoreline changes and Erosion Hazard assessment: case study in Muriganga–Saptamukhi interfluve, Sundarban, India

Quantitative techniques, statistical methods and mathematical rules make the geospatial analysis more systematic, accurate and precise. In order to measure the intensity of the ongoing processes on the earth surface, evaluate the spatio—temporal changes in geographical attributes, highlight the principal factors for any geographic events and to identify the future possibilities, quantitative techniques are for most dependable. In the present article sequential changes of the shoreline, spatio—temporal extent of erosion and depositional processes of Sundarban region, West Bengal, India, have been measured following the selected quantitative techniques. The Sundarban is one of the most dynamic geomorphic units in the earth surface, situated in the northern apex of Bay of Bengal. The region has formed, sculptured and modified due to continuous sedimentation of the Ganga and the Brahmaputra systems, intense tidal hydro dynamic behavior, climatic disturbances and anthropogenic activities. In the last two century most of the parts of the active Sundarban delta has being reclaimed and occupied with dense rural settlements, most of the peoples are engaged in agriculture based rural economy, hence substantial erosion and successive regressive changes in the area have an unconstructive impact on the dwelling communities. In order to examine the net shoreline changes, average rate of end point changes and extent of erosion and depositional processes Survey of India toposheets of 1920, 1921, 1922, 1923, US Army toposheets of 1955, Survey of India toposheets of 1967, 1968, 1969 and IRS P6 LISS IV satellite images of 2014 have been used. Finally erosion hazard zones have been identified will help of net area changes of the each geomorphic units to access the spatial variation of erosion hazard intensity. Quantitative model has been prepared on the basis of multi temporal data of Muriganga–Saptamukhi interfluve area of western Sundarban which can be applied to the other parts of Sundarban region.

Morphometric analysis of Usri River basin, Chhotanagpur Plateau, India, using remote sensing and GIS

A geomorphic unit Usri drainage basin (latitude: 24° 04′00″ N to 24° 34′00″ N and longitude 86°05′00″E to 86°25′00″E) lies in north-eastern parts of Chhotanagpur Plateau, India, has been selected for morphometric analysis. Digital elevation model (DEM) has been generated by Cartosat stereo pair data at 10-m resolution. The morphometric parameters considered for the analysis includes the linear, areal, and relief aspects of the basin. Morphometric analysis of the river network and the basin revealed that the Usri Basin has sixth-order river network with a dendritic drainage pattern. The dendritic drainage pattern indicates that the basin has homogeneous lithology, gentle regional slope, and lack of structural control. The bifurcation ratio between different successive orders varies but the mean ratio is low that suggests the higher permeability and lesser structural control. The low drainage density, poor stream frequency, and moderately coarse drainage texture values of the basin indicate that the terrain has gentle slope, is made up of loose material, and hence has good permeability of sub-surface material and significant recharge of ground water. The shape parameters indicate that the basin is elongated in shape with low relief, high infiltration capacity, and less water flow for shorter duration in basin. The 50 % of the basin has altitude below 300 m and gently sloping towards the southeast direction. All the morphometric parameters and existing erosional landforms indicated mature to early old stage topography.

Demarcating saline water intrusion pathways using remote sensing, GIS and geophysical techniques in structurally controlled coastal aquifers in Southern India

Application of remote sensing and geographical information system (GIS) with the help of ground truth studies like vertical electrical soundings (VES) and water quality measurements gave a comprehensive picture on saline water intrusion pathways in the structural controlled aquifers of Uppanar and Cauvery River systems located in Sirkazhi and Mannanpandal coastal areas of Southern India. The detailed geomorphic units and lineaments were mapped using IRS LISS-III (1:50,000 Scale) and SRTM Elevation Digital data under GIS environment. The area is mainly alluvial deposits of Holocene Age and classified into three major geomorphic units (i.e., fluvial, fluviomarine, and marine geomorphic units). The identified lineaments are mostly trending North-northeast (NNE)–South-southwest (SSW), Northeast (NE)–Southwest (SW), Northwest (NW)–Southeast (SE), East–West (EW) and East-Northeast (ENE)–West-Southwest (WSW) directions. Some of them are potential for fresh groundwater occurrence and movement. The lineaments trending NE–SW, NNE–SSW, and ENE–WSW act as pathways for saline water intrusion to the inland. The lineament L1 (NNE–SSW trending) conformed as a sinisterly shifted fault played a significant role in saline water intrusion. The area within the parallel lineaments L2 and L3 oriented ENE–WSW direction indicates low topography, beach ridges, paleo-channel sinuosity, large aerial extent of tidal flats, and backwater inundation. All the above geomorphic units gave indirect evidence of land subsidence, which was confirmed with the help of sub-surface geo-electrical signals obtained through VES and in situ groundwater quality measurements. Integrating all the above results, the saline water spread and fresh water pockets were identified.

Coastal erosion and mass wasting along the Canadian Beaufort Sea based on annual airborne LiDAR elevation data

Erosion of permafrost coasts has received increasing scientific attention since 1990s because of rapid land loss and the mobilisation potential of old organic carbon. The majority of permafrost coastal erosion studies are limited to time periods from a few years to decades. Most of these studies emphasize the spatial variability of coastal erosion, but the intensity of inter-annual variations, including intermediate coastal aggradation, remains poorly documented. We used repeat airborne Light Detection And Ranging (LiDAR) elevation data from 2012 and 2013 with 1m horizontal resolution to study coastal erosion and accompanying mass-wasting processes in the hinterland. Study sites were selected to include different morphologies along the coast of the Yukon Coastal Plain and on Herschel Island. We studied elevation and volume changes and coastline movement and compared the results between geomorphic units. Results showed simple uniform coastal erosion from low coasts (up to 10m height) and a highly diverse erosion pattern along coasts with higher backshore elevation. This variability was particularly pronounced in the case of active retrogressive thaw slumps, which can decrease coastal erosion or even cause temporary progradation by sediment release. Most of the extremes were recorded in study sites with active slumping (e.g. 22m of coastline retreat and 42m of coastline progradation). Coastline progradation also resulted from the accumulation of slope collapse material. These occasional events can significantly affect the coastline position on a specific date and can affect coastal retreat rates as estimated in long term by coastline digitalisation from air photos and satellite imagery. These deficiencies can be overcome by short-term airborne LiDAR measurements, which provide detailed and high-resolution information about quickly changing elevations in coastal areas.

Geomorphological evolution of marine heads on the eastern coast of Red Sea at Saudi Arabian region, using remote sensing techniques

The eastern coast of the Red Sea is characterized by the presence of numerous marine heads that differ in terms of shape, size, geological setting, structures, and composition. This difference directly affects geomorphological evolution. In the present study, Ras Al-Shabaan was chosen as a most important area in this coast. Field investigations supported with photo-interpretation techniques were performed for studying of geomorphological features of Ras Al-Shabaan. On the other hand, the remotely sensed imagery data has been used extensively in the identification of geological and geomorphological details of Ras Al-Shabaan. The geomorphological studies showed that depositional processes of wadis and channels are predominant at the Ras Al-Shabaan coast. The changes in geomorphological and geological data of Ras Al-Shabaan were identified by remote sensing image software. Two Landsat ETM+ images from 1990 and 2010 have been processed. The analysis of remote sensing data combined with field investigations and reference data were used to monitor, delineate, and describe the geomorphological changes of Ras Al-Shabaan coast during proceedings of supervised classification of ground units. Hence, the change detection statistics have been used in ground units. Geological and geomorphological maps were digitized by using ArcGIS software. Remote sensing techniques and geographic information system (GIS) were employed in order to monitor the results of changes occurred in the line of the coast. The satellite image processing and water index data were transferred to the ArcGIS program to draw the coast lines and to stand on the changes occurred. Thereby, it was possible to identify the most prominent landforms and geomorphic units of this area. Results showed that platforms, barriers, rocky heads, islands, coral reefs, submerged reefs, tidal channels, dissolution grooves, sabkhas, inlet system, waves work, and shoreline processes were included in coastal prominent landforms. The circumstances that formed this coast are not permanent, as it is changing rapidly and continuously due to erosion and uplift processes.

Demarcation of Groundwater Feasible Region using GIS and Fuzzy Logic

Assessing the potential zone of groundwater recharge is extremely important for the protection of water quality and the management of groundwater systems. It is therefore, necessary to integrate the several factors on these terrain characteristics. Remote sensing and Fuzzy logic now-a-days have become inevitable tools for the analysis of groundwater at local, regional and global level. Fuzzy logic based concepts have found a very wide range of applications in different field and this membership functions assessed for overlay maps were mainly extracted from the field data. The benefit is that they don't need to conduct a new analysis, or change the rules, or the criteria, which saves time and effort. In the study area a standard methodology is proposed to confirm the groundwater potential using combination of RS & GIS technique and fuzzy logic system. The integrated map is generated using GIS tools and other map like geology, slope, drainage density, geomorphic units and lineament density are generated using the satellite data and survey of India (SOI) toposheets of scale 1:50000. It is then integrated with weighted overlay in ArcGIS and Fuzzy logic model using matlab. The use of suggested methodology will be useful for efficient classification of appropriate locations for withdrawal of water in noyyal river basin.

CARACTERIZACION GEOMORFOLOGICA DE LA LLANURA DELTAICA DEL RIO MAGDALENA CON ENFASIS EN EL SISTEMA LAGUNAR DE LA CIENAGA GRANDE DE SANTA MARTA, COLOMBIA

The plain located between Magdalena river and Sierra Nevada de Santa Marta has been divided into five geomorphic units: Magdalena floodplain; present delta lagoon system; marginal lagoon system; beach and barrier island and alluvial foothill plain. The features of each one are product of specific events in time. The marginal lagoon system and its barrier island conform a scheme of lagoon - barrier - sea. Salamanca shore is dominated by waves and is subjected to recession. A general cross section of the island includes seabeach- dunes-plain with vegetation-salt pan-plain with vegetation-mangrove-lagoon. The marginal lagoon system (which includes Ciénaga Grande) is strongly dependent of vegetation. Toward northwest desertification is the dominant process and toward northeast (alluvial foothill plain) it,s

A New Approach to the Land Capability Classification: Case Study of Turkey

Land capability classification is one of the very important issues in terms of sustainable land use. Many land capability classifications have been prepared and applied especially in the developed countries such as USA, UK and France. Most of the land capability classification systems and mapping are an adaptation of the US Department of Agriculture method. Up to now the criteria that are taken into consideration in the land capability classification are topography especially inclination of slope and soil properties, in general. In a mountainous country or regions topographic-geomorphic unites, climate and parent material are factors that must be taken into consideration in order to establish land capability classification. All these criteria are used in this study. The aim of this study is to reestablish a land classification according to the geomorphic units, climate and parent material factors in Turkey. According to these criteria, seven land capability classes were determined. Moreover, the subclass are identified according the parent material properties that mostly outcropped on the mountainous areas.

Geomorphic Site Analysis to Study Soils Developed on a Toposequence of Schist Landform in Yadgir District of Karnataka

Three representative diversified pedons namely red, brown and black from the geomorphic units upper, middle and lower sectors, respectively in a toposequence on schist landscape were studied for their morphological, physical and chemical properties to understand the genesis and to classify as per USDA Soil Taxonomy. Red pedon was well drained as it recorded the highest (3) moist chroma and the drainage got poor down the slope in brown and black pedons where the moist chroma was 2 and 1, respectively. Dominant soil colour hue was 5YR in red pedon and 7.5 YR and 10 YR in brown and black pedons, respectively. Soil texture got finer down the slope and it was gravelly clay loam in red pedon and clay in both brown and black pedons. Clay skins, pressure faces and slickensides were observed in red, brown and black pedons, respectively. Chemical composition of fine sand fraction of pedons was almost same in all the pedons and CEC/clay, Feo/Fed and SiO2/Fe2O3 ratios showed increasing trend down the slope. The pedogenic processes associated with the upper sector member red pedon were leaching, decalcification, tendency of desilicification, laterization and kaolinization under well drained condition whereas, the middle and lower sector members brown and black pedons were formed by the pedogenic processes like calcification and silicification under poor drainage condition. Thus, a difference in drainage conditioned by topography is the important pedogenic factor in the genesis of diversified soils in a toposequence. At sub group level red, brown and black pedons were classified as Typic Haplustalfs, Vertic Haplustepts and Leptic Haplusterts, respectively.

Assessing instream habitat suitability and hydraulic signatures of geomorphic units in a reconstructed single thread meandering channel

AbstractStream channel reaches consist of a series of geomorphic units (e.g. pools, runs and riffles) that mitigate flow velocity and provide a variety of aquatic habitat. The hydraulic signature of each geomorphic unit is unique and should remain so during variable flow conditions in order to satisfy habitat requirements. We use the hydraulic signatures measured at different geomorphic units in a recent channel realignment project to evaluate suitability of reaches and geomorphological units for target fish species. In 2009, 650 m of creek and valley were realigned in Brampton, Ontario, to facilitate development. In 2013, water velocity, depth, temperature and channel substrate were measured at cross‐sections between 1 May and 15 October. The assessment illustrated that while geomorphic units have unique signatures during moderate to low‐flow conditions, at high‐flow conditions the boundaries between geomorphic units blurred. Furthermore, our findings suggest that suitable water depth, velocity and temperature conditions existed at least 68% of the time over the entire study period but was reduced during the estimated spawning period for the target species. Specifically, water depth was only ideal for approximately 38% of the spawning period. Finally, in cases where both geomorphic and ecologic systems interface (e.g. channel restoration), it is important to view the whole picture. This study contributes to the on‐going discussion on restoration and success and is particularly useful in light of recent stream restoration trends in rapidly expanding urban regions around the globe. Copyright © 2015 John Wiley & Sons, Ltd.

Relationships between woody vegetation and geomorphological patterns in three gravel-bed rivers with different intensities of anthropogenic disturbance

We compared three gravel-bed rivers in north-eastern Italy (Brenta, Piave, Tagliamento) having similar bioclimate, geology and fluvial morphology, but affected by different intensities of anthropogenic disturbance related particularly to hydropower dams, training works and instream gravel mining. Our aim was to test whether a corresponding difference in the interactions between vegetation and geomorphological patterns existed among the three rivers. In equally spaced and sized plots (n = 710) we collected descriptors of geomorphic conditions, and presence–absence of woody species. In the less disturbed river (Tagliamento), spatial succession of woody communities from the floodplain to the channel followed a profile where higher elevation floodplains featured more developed tree communities, and lower elevation islands and bars were covered by pioneer communities. In the intermediate-disturbed river (Piave), islands and floodplains lay at similar elevation and both showed species indicators of mature developed communities. In the most disturbed river (Brenta), all these patterns were simplified, all geomorphic units lay at similar elevations, were not well characterized by species composition, and presented similar persistence age. This indicates that in human-disturbed rivers, channel and vegetation adjustments are closely linked in the long term, and suggests that intermediate levels of anthropogenic disturbance, such as those encountered in the Piave River, could counteract the natural, more dynamic conditions that may periodically fragment vegetated landscapes in natural rivers.

Climate-Driven Landformof the Ejina Basin (NW China) in Central Asia and Its Paleoenvironmental Implications

<p>Though neotectonic activity is believed to be the major factor in the evolution of the topography of the Ejina Basin in Central Asia, detailed documentation and analysis of climatic landscape features and their environmental implications are lacking. The present study is a site-specific documentation of landforms developed in the wide part of the Ejina Basin, with the aim to identify the climatic landforms based on the method of climatic geomorphology and to evaluate its landscape evolution and response to palaeoclimate changes. The morphodynamics of older landscapes are recognized by making comparison with the present climate and its corresponding landscapes. Clear evidences testifying the basin-scale shifting and transformation of different morphoclimatic zones in the basin are observed, which prove that the main geomorphic unit is changed from an alluvial-lacustrine plain to a desert plain. The coexistence of diverse landscapes and the consequent geomorphodiversity in the basin should be a compound result of surficial processes other than glaciations. The climate and hydrological conditions of the basin during the last glaciation and during the Early Holocene were much better than at present, possibly having an average annual precipitation ranged between 60~350 mm on <del cite="mailto:unknown" datetime="2015-11-27T09:00"> </del>the basin during ca. 39-23 ka BP but great fluctuations during Holocene. The periods of lower aridity during the late Pleistocene in the bain could be induced by an increase of the westerlies and a weakening of the Asian winter monsoon on the arid areas of the central Asia.</p>

Seasonal variation of water quality parameters in different geomorphic Channels of the upper Malwathu Oya in Anuradhapura, Sri Lanka

Malwathu Oya is a perennial river in the Dry Zone of Sri Lanka. Water of the nearby paddy lands is diverted to the river from different locations during cultivation seasons. These anthropogenic activities cause stresses on Malwathu Oya by impairing the quality of its water. The main objective of this study was to assess the seasonal fluctuation of nitrate, phosphate, chloride, dissolved oxygen (DO) and turbidity of river water in different locations of Malwathu Oya. The study was carried out in the upper part of Malwathu Oya from Ritigala to Nachchaduwa in the Anuradhapura District. Data were collected continuously for twelve months from March 2012 to February 2013. Factorial analysis was carried out to study the interactions among different factors (study site location, climatic season, channel geomorphic unit and river segment). The mean nitrate, phosphate, chloride and DO concentrations ranged from 1.05 to 5.28, 0.004 to 0.043, 2.63 to 8.72, 3.11 to 8.50 mg/L, respectively, and the mean turbidity level ranged from 81.75 to 256.10 NTU. The nitrate, phosphate and chloride concentrations were significantly higher (p 0.05) in DO and turbidity in paddy and non-paddy areas. The results concluded that the water quality parameters except turbidity in the investigated area of Malwathu Oya were within the threshold limits for dinking purposes. Tropical Agricultural Research Vol. 25 (2): 158 – 170 (2014)

Exploring large wood retention and deposition in contrasting river morphologies linking numerical modelling and field observations

AbstractLarge wood tends to be deposited in specific geomorphic units within rivers. Nevertheless, predicting the spatial distribution of wood deposits once wood enters a river is still difficult because of the inherent complexity of its dynamics. In addition, the lack of long‐term observations or monitored sites has usually resulted in a rather incomplete understanding of the main factors controlling wood deposition under natural conditions. In this study, the deposition of large wood was investigated in the Czarny Dunajec River, Polish Carpathians, by linking numerical modelling and field observations so as to identify the main factors influencing wood retention in rivers. Results show that wood retention capacity is higher in unmanaged multi‐thread channels than in channelized, single‐thread reaches. We also identify preferential sites for wood deposition based on the probability of deposition under different flood scenarios, and observe different deposition patterns depending on the geomorphic configuration of the study reach. In addition, results indicate that wood is not always deposited in the geomorphic units with the highest roughness, except for low‐magnitude floods. We conclude that wood deposition is controlled by flood magnitude and the elevation of flooded surfaces in relation to the low‐flow water surface. In that sense, the elevation at which wood is deposited in rivers will differ between floods of different magnitude. Therefore, together with the morphology, flood magnitude represents the most significant control on wood deposition in mountain rivers wider than the height of riparian trees. Copyright © 2015 John Wiley & Sons, Ltd.

Temporal and Spatial Patterns of Fish Response to Hydromorphological Processes

AbstractThis paper relates life cycle characteristics of fishes, their environmental tolerances, habitat requirements, and resilience against hydromorphological disturbances to a recently developed river typology providing a hierarchy of spatial units. It aims to identify the most relevant spatiotemporal scales for river restoration and environmental assessment.Most fish species, except diadromous and some potamodromous species, can complete their life cycle within a river reach and form sustainable populations within a river segment. They typically move within the spatial scale of river segments and have their home range within the river reach. By comprising heterogeneous patterns of different geomorphic and hydraulic units, the reach provides habitat complexity and heterogeneity that supports river‐type‐specific fish assemblages. The single units are often used temporarily or by specific life stages only underpinning the need for habitat diversity. Further, they might be only temporarily available. River fishes have evolved several life cycle adaptations to improve their resilience against stochastic disturbances, as high fecundity, multiple spawning, batch‐spawning, a protracted annual spawning season, and long life‐time fecundity with multi‐cyclic spawning. Therefore, they are well adapted to environmental variations driven by hydromorphological processes.Considering the home range of most species, representative sampling at the reach scale will cover all functional river elements, hydraulic, and geomorphic units, while accounting for their temporary or sporadic use by fish. Therefore, the reach scale appears as practicable and sufficient scale for fish‐based assessments and as highly relevant planning unit in hydromorphological river restoration practise. Nonetheless, reach‐scale characteristics are largely inherited from large‐scale geomorphic processes and multiple pressures at the catchment scale that may impact aquatic communities and river restoration success at the lower spatial scales. Copyright © 2015 John Wiley & Sons, Ltd.

ALTERAÇÃO NA COBERTURA VEGETAL E USO DA TERRA DA BACIA HIDROGRÁFICA DO ALTO RIO TOCANTINS (GOIÁS): INFLUÊNCIA DAS CARACTERÍSTICAS FÍSICAS E A RELAÇÃO COM AS COMUNIDADES INDÍGENAS

The aim of this study is to analyze the land use and land cover in the upper Tocantins river basin, Goias state, based on the spatial changes in the range of 29 years, the influence of the physical aspects of its dynamic and its impacts on indigenous communities. The methodology was based on GIS techniques and literature. The spatial area was defined from the processing of digital eleva tion models (DEM), in reference to the drainage basin confluent to “Serra da Mesa” hydroelectric plant (HEP), northern state of Goias . Landsat 5 and 8 satelite images were used, which were preprocessed, classified and highlighted. The characterization of the physical environment was carried from the compilation of thematic maps (geological units, geomorphic units and soils) and the MDE. To associate the indigenous community, literature search was performed, searching the literature, publications related to the recent history of Indigenous Territories in the area. The classification resulted in a land cover and land use map with three classes: Cerrado, Anthropogenic cover and Water bodies. Over the past 29 years there was a change in predominant class, from cerrado to anthropogenic cover. This alterations occupy, mainly, areas of Oxisols in flat reliefs, in regional planation surface. In the same period, the scenario of landscapes transformation hit two indigenous communities: the Ava - Canoeiro, with the emergence of HEP, and the Tapuia by land pressure. This spatial configuration directs the conservation of Cerrado remaining (fragments) present in the study area.

Indicators of river system hydromorphological character and dynamics: understanding current conditions and guiding sustainable river management

A set of multi-scale, process-based hydromorphological indicators of river character and dynamics has been developed to support river management and restoration activities. Indicators are selected to represent key hydromorphological processes at each spatial scale, i.e., catchment, landscape unit, river segment, river reach. Their evaluation allows identification of the cascade of these processes through the spatial units and the historical changes in their propagation as a consequence of natural or human induced hydromorphological changes. The approach is deliberately open-ended so that it can be adapted to local environmental conditions and management, and it can make the most effective use of available data sets. The indicators support assessments of the current condition of the river and its catchment; past changes within the catchment and their impacts on river reaches. Therefore, they represent a sound foundation for assessing the way the catchment to reach scale units and the geomorphic units within reaches may respond to future natural changes or human interventions. The procedure is illustrated using the example of the river Frome (UK).