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Accurate flood risk assessment is essential for effective risk management, especially as extreme rainfall trends have increased flood frequency and inundation globally. However, rainfall data alone often becomes insufficient in dynamic floodplains, where geomorphological changes are critical. The Shilabati River basin in West Bengal, India, illustrates such a landscape, having experienced severe floods in 1959, 1967, 1968, 1973, 1978, 1999, 2000, 2007, 2013, and 2021. For this basin, mapping landform variability is key to understanding erosion and landscape denudation processes. The Digital Elevation Model (DEM)-based technique known as DEM of Difference (DoD) enables the detection of terrain changes over time by comparing DEMs from distinct periods, offering insight into floodplain erosion. However, DEM-based analysis is prone to spatially correlated errors, which can propagate false topographic features, hindering accurate flood mapping. Our study employs the Elevation Deviation Index (EDI), a DEM comparison method that normalizes and mitigates spatially correlated errors across terrain. Using EDI, we mapped geomorphological changes in the Shilabati floodplain, revealing substantial erosion and elevation loss. Our findings demonstrate a strong positive correlation between EDI values and increased flood extent. These results underscore the importance of incorporating geomorphological analysis in flood risk assessment, as hydrological data alone may overlook critical terrain changes. We recommend a Preliminary Flood Risk Assessment (PFRA) to strengthen flood resilience in the region, targeting vulnerable zones for enhanced, adaptive flood mitigation strategies. [ABSTRACT FROM AUTHOR]

Here, we explore the dynamic interplay of climate, tectonic forces and human impacts, that have shaped the current hydrology of the 27 main endorheic continental playa-lakes in southern Spain, most of them protected as Natural Reserves. This research offers a thorough examination of the hydro-geomorphic, geochemical, and tectonic characteristics that influenced the development of these wetlands. We introduce and apply several hydro-morphological indices that effectively characterize the hydrological functioning of these wetlands. Importantly, the examination of the geological setting and analysis of recent tectonics has been found to be effective in reconstructing the evolution of some of the major playa-lakes, including Fuente de Piedra playa-lake and El Gosque playa-lake. Lastly, the analysis of satellite information using the online tool water occurrence change intensity (WOCI) of Surface Water Explorer in the studied playa-lakes was found to be inconsistent in the long-term analysis. Enhanced attention is required to refine the WOCI tool, thereby ensuring a more precise depiction of wetland dynamics in the Mediterranean. Fine-tuning will better represent complex behaviors, thus improving its utility for monitoring and managing wetlands in the region. [ABSTRACT FROM AUTHOR]

The presence of water resources, particularly rivers, significantly influences site selection. Throughout history, settling near rivers has brought numerous advantages, but it has also posed certain risks. This study focuses on the subbasins southeast of the Caspian Sea. Initially, we explore the connection between the layout of ancient settlements and the drainage networks. Additionally, we analyze the relationship between flood risk and the settlement patterns of these ancient sites by estimating the flooding risk based on linear, areal, and relief aspects. This research marks the first time such an analysis has been conducted. The findings underscore the importance of proximity to rivers in site selection, with areas close to rivers with lower stream orders being the most favorable for settlements. The study reveals a decrease in the frequency of sites near higher stream orders in relation to flooding risk. Conversely, there is an increase in the frequency and density of ancient sites near the first stream orders and at greater distances from the rivers, coinciding with an elevated flooding risk in the sub-basins. These results indicate that the inhabitants of the southeastern areas of the Caspian Sea sub-basins were cognizant of the flooding danger and factored it into their decision-making when selecting settlement sites. [ABSTRACT FROM AUTHOR]

This paper presents the results of multidisciplinary research which addresses the issue of sustainability within the design of urban agricultural landscapes through the joint solution of architecture and hydro-geomorphology for the management, accessibility and use of urban agricultural landscapes. If the traditional separation between urban and productive land has now been overcome by the inclusion of agricultural areas within the cities, what is still under discussion is how to make its planning sustainable, especially in densely urbanized contexts. This research was developed with a methodology able to combine different types of data in order to satisfy needs relating to the availability of water for land supply and to make this landscape—both rural and urban—accessible to the city. Historical traces, interpretative insights, and hydro-geomorphological reading models of the territory were analysed. Their interweaving has made it possible to develop a prototype of a water and landscape infrastructure that combines a system for subsurface water, cycle–pedestrian paths and small-scale architecture features around the water tanks. The research has been tested in the city of Pozzuoli (NA) in Southern Italy, within the Monteruscello neighbourhood. The result led to a design solution of an integrated system which contributes to implementing the green transition within cities. [ABSTRACT FROM AUTHOR]

Abstract Water is an indispensable natural resource for survival of any species in the globe. For centuries, civilization has flourished on the bank of river based on the easy availability of water. Groundwater is one of the prime sources of freshwater supply, but, its occurrence and spatial distribution are highly uneven and affected by several surface and subsurface features. Development of several geospatial tool based on the remote sensing and GIS in recent time helps immensely for delineation and management of this precious resource. The present study has been undertaken in south-western part of Birbhum district, West Bengal with an objective to delineate groundwater potential zone using multiple criteria decision analysis and GIS. Seven thematic layers concerning with geology, geomorphology, hydrology, land use land cover and edhaphic factor have been employed in this study with proper weightage depending on their role in groundwater formation to identify the groundwater potential zone. By using analytical hierarchy process, whole study area has been classified into four zones ranging from excellent to poor. Primary field data and secondary data about depth of groundwater have been compared with the result to make it authentic. The result shows that the southern part composed of alluvial plain has the excellent potential compared to the northern lateritic and pediment part where groundwater potential is moderate. Eventually, few recommendation and suggestion have been framed for sustainable water resource management that will help the researchers, planners and other decision-makers for judicious exploration and management of the groundwater resource in the study area.

Sundarban is made up of a mesh of macrotidal estuarine systems that contain the world's largest mangroves, the eco-geomorphic environment of which is heavily influenced by tidal behaviour and flow characteristics. The present study aimed to identify the tidal attributes and document the flow character of Indian Sundarban throughout a fortnightly tidal cycle. As such, seven tide monitoring stations were installed across the Saptamukhi-Hariabhanga and connected river system to monitor tidal water levels. Based on this data, the Institute of Ocean Sciences' (IOS) method was used to extract 17-major tidal harmonic components to study the links between various oceanic and shallow-water tidal constituents that may contribute to tidal asymmetry. A Mike-21-flow model was also run to simulate the tidal flow of the regime. Result shows that the progression and convergence of tidal waves in the funnel-shaped estuarine system causes notable lag between the southern and northern limits (avg. 45 min over a 52 km-long stretch of Thakuran estuary). The harmonic components indicate that semi-diurnal M2, S2; over tide 2MS6; and diurnal O1, K1 are the major forces, shaping the tidal amplitude in this region. The third, fourth, and sixth diurnal constituents represent additional tidal components, although with relatively minor amplitudes. The transition from coastal to headward stations sees a shift in the relative phase from 93.73° to 96.17°, suggesting a flood dominance and minimal dissipation of energy within the system. Mike-21FM found that the spring flood-current speed with an average value of 0.42–0.56 m/s is significantly higher than the ebb current of averaging 0.25–0.32 m/s. The nature of neap tidal current speed in the Sundarban region generally mirrors that of the spring condition, although with much less intensity. We assume that since any bi-weekly hydraulic analysis has not yet been conducted in Sundarban, it may be highly valuable for future studies. • First-ever biweekly analysis of tide and tidal flow in Indian Sundarban. • IOS and Mike.21 FM models validated with field data in numerical study. • Identified 17 tidal elements; region interpreted as semi-diurnal; flood dominated. • Flood-driven tidal system deposits in inner areas, erodes near edges. [ABSTRACT FROM AUTHOR]

Water is an indispensable natural resource for survival of any species in the globe. For centuries, civilization has flourished on the bank of river based on the easy availability of water. Groundwater is one of the prime sources of freshwater supply, but, its occurrence and spatial distribution are highly uneven and affected by several surface and subsurface features. Development of several geospatial tool based on the remote sensing and GIS in recent time helps immensely for delineation and management of this precious resource. The present study has been undertaken in south-western part of Birbhum district, West Bengal with an objective to delineate groundwater potential zone using multiple criteria decision analysis and GIS. Seven thematic layers concerning with geology, geomorphology, hydrology, land use land cover and edhaphic factor have been employed in this study with proper weightage depending on their role in groundwater formation to identify the groundwater potential zone. By using analytical hierarchy process, whole study area has been classified into four zones ranging from excellent to poor. Primary field data and secondary data about depth of groundwater have been compared with the result to make it authentic. The result shows that the southern part composed of alluvial plain has the excellent potential compared to the northern lateritic and pediment part where groundwater potential is moderate. Eventually, few recommendation and suggestion have been framed for sustainable water resource management that will help the researchers, planners and other decision-makers for judicious exploration and management of the groundwater resource in the study area. [ABSTRACT FROM AUTHOR]

The analysis of morphometric parameters gives a precise scenario about the geomorphic characteristics and the hydrological behaviour of a drainage basin, especially in the areas where hydrological data are unavailable due to the absence of a gauging station or inaccessibility for harsh topographic conditions. So, the current study is aimed to investigate the hydro-geomorphic characteristics of the Rayeng basin in Darjeeling Himalaya. The extraction and analysis of the morphometric variables of the study area were done using remote sensing and GIS. The spatial disparity in drainage density, lineament density, stream frequency, texture ratio, and infiltration number has inferred that the Rayeng basin is carried a high runoff intensity and low infiltration rate on the upper reaches and an inverse situation in the lower reaches. The extracted ruggedness index and Melton's Ruggedness index indicate the unevenness of the topography and normal flow in the main channel in the Rayeng basin. A distinctive topographic diversity is also depicted by the basin's Topographic Positioning Index (TPI). A significant spatial variation of water availability in this basin is indicated by the Topographic Wetness Index (TWI); the depressed areas of the basin have higher TWI compared to the steep-sloped high land. The basin's hypsometric integral (HI) is inferred youthful stage. This basin has a good potentiality of water which can be sustainably used by the people of the lower reaches of the basin. This study will be helpful to assess the hydro-geomorphic characteristics of a drainage basin where hydrological data are not available.

Floodplain wetlands in the arid and semi-arid regions are highly threatened by complex changing environments. In order to better understand the response of wetland landscape patterns to floodplain hydro-geomorphology and landuse changes in drylands, this study aims to explore the spatiotemporal variation and underlying mechanisms of the floodplain wetland landscape patterns of the Yellow River in the arid and semi-arid region during 1973–2014. Based on the time-series Landsat observations, land use and hydrological data, the directional distribution, connectivity indicators, as well as univariate and multivariate linear regressions were used to analyze the trends and variations of wetland landscape pattern changes and their relationship with floodplain hydro-geomorphology and land use changes. Our results showed that the floodplain wetlands became more fragmented during 1973–2014, characterized by a decrease (6756 ha) in the total wetland patch area and an increase (353) in the number of patches. The center point of the wetlands in the whole study area migrated from the southwestern to northeastern part (0.8 km in the east direction and 1.7 km in the north direction). The greatest migration of the center point of wetlands occurred during the combined operation of the Longliu reservoirs, indicating that the decreasing frequency of large floods and unstable channel resulted in the fragmentation and migration of the overall wetlands. In addition, the operation of dam augmented the influence of hydro-geomorphology on the wetlands. Ice flooding benefed the formation of new wetlands and accelerated the migration of the overall wetlands. Land use changes due to the practice of various protection policies did not pose impact on the spatiotemporal changes of wetlands. Thus, a better understanding of the wetland landscape pattern changes in unstable floodplains requires considering both the floodplain hydro-geomorphology and land use changes, which is supportive to sustainable river floodplain management.

Morphometric analyses play a vital role in hydrological investigations. The application of GIScience and processing techniques have greatly facilitated this through delineation of morphological features or drainage pattern, development and management of drainage basin, groundwater potential mapping, etc. to meet sustainable development goals. The Ghaggar river basin is located between Latitudes 27°39' N - 32'N 32'N and Longitudes 73? 55'E - 77°36' E and covering an area of 20,454.08 sq.km elevation ranges from 169 metres to 1884 metres above MSL. The river originates from District Sirmaur in Himachal Pradesh and flows through Punjab, Haryana and Rajasthan. In the present study, the morphometric analysis of Ghaggar river basin has been performed to study the various drainage parameters using geospatial technique. The morphometric analysis shows that the watershed has five mini watersheds, sixth order stream segment, drainage network is dendritic in nature, drainage density is 0.434 km per sq. km, stream frequency is 0.096 streams per sq. km, bifurcation ratio of all mini watersheds is 2 to 12, Various morphometric parameters such as linear, aerial and relief aspects have been correlated with each other to apprehend their fundamental association and their influence over basin hydrogeomorphology, soil and topography. The geomorphic parameters are of immense utility in developing proper disposition and decision making of watershed for natural resource appraisal, catchment area advancement, watershed characteristics, planning and drainage development. [ABSTRACT FROM AUTHOR]

The extent and intensity of impacts of multiple new dams in the Amazon basin on specific biological groups are potentially large, but still uncertain and need to be better understood.It is known that river disruption and regulation by dams may affect sediment supplies, river channel migration, floodplain dynamics, and, as a major adverse consequence, are likely to decrease or even suppress ecological connectivity among populations of aquatic organisms and organisms dependent upon seasonally flooded environments.This article complements our previous results by assessing the relationships between dams, our Dam Environmental Vulnerability Index (DEVI), and the biotic environments threatened by the effects of dams. Because of the cartographic representation of DEVI, it is a useful tool to compare the potential hydrophysical impacts of proposed dams in the Amazon basin with the spatial distribution of biological diversity. As the impact of Amazonian dams on the biota of both rivers and periodically flooded riparian environments is severe, DEVIs from different Amazonian tributary basins are contrasted with patterns of diversity and distribution of fish, flooded forest trees and bird species.There is a consistent relationship between higher DEVI values and the patterns of higher species richness and endemism in all three biological groups. An assessment of vulnerability at the scale of tributary basins, the assessment of biodiversity patterns related to DEVI, and the analysis of teleconnections at basin scale, demonstrate that recent construction of dams is affecting the biota of the Amazon basin.The evidence presented here predicts that, if currently planned dams are built without considering the balance between energy production and environmental conservation, their cumulative effects will increase drastically and represent a major threat to Amazonian biodiversity. [ABSTRACT FROM AUTHOR]

In this paper, we studied the geo-hydrological structure and behavior of a reference catchment, located in the Cilento UNESCO Global Geopark, southern Italy, representative of the hilly, terrigenous and forested headwaters of the Mediterranean eco-region. Based on detailed hydrogeological and hydro-geomorphological surveys and geomorphometric analysis, starting in 2012, a hydro-chemical monitoring activity at the catchment and sub-catchment scale started, and a hydro-chemical dataset was progressively recorded at daily and sub-hourly time steps. Based on this dataset, the authors performed an original procedure to identify different runoff components, derived by applying cascade mass balance filtering. The integration of hydrological and geomorphological approaches allowed us to obtain an interesting conceptualization of the storm flow generation using hydro-chemical signatures related to different runoff components produced during the increasing–decreasing cycle of the flood event magnitude. The hydro-system activated progressively different runoff sources (i.e., groundwater, riparian corridor, hillslope and hollow) and involved various mechanisms (i.e., groundwater ridging, saturation-excess, infiltration-excess and soil pipe exfiltration). The geo-hydrological conceptualization was validated using a hysteresis Q-EC loop analysis performed on selected events that showed how hysteretic indices could be used to characterize the events in respect to their origins, mechanisms and pathways in similar catchments. [ABSTRACT FROM AUTHOR]

Fluoride is a colourless micro-nutrient which is highly required for the strong teeth and bones. The above and below the prescribed range (0.6–1.5 mg/l) of fluoride in drinking water is harmful or hazardous for human health. Granite gneiss and pegmatite are the natural sources of fluoride minerals in this North Singbhum Craton. Purulia district which is the extended part of Chhota Nagpur Gneissic complex hosts such fluoride bearing rocks and minerals. About 619 water samples were collected from different parts of the district. Different rock samples have been collected from exposed litho-strata with prominent geological structures through Garmin GPS Etrex 30x. Sample sites have been geocoded on SRTM DEM and rocks are tested in the laboratory to examine the concentration of fluoride ions. The study was conducted to identify the natural and anthropogenic sources of fluoride and find out the relationship among the fluoride, geology with structures, hydro-geomorphology, soil and aquifer. Lineament features have been extracted using different bands of two specific images, namely ETM and ASTER. Digital mapping techniques including spatial analysis are used to detect the geomorphological attributes using SRTM and ASTER DEM data with adequate ground verification. Finally, Fluoride Contamination Index (FCI) map has been prepared by Thomas L. Saaty (1984) Analytical Hierarchy Process (AHP) using weighted sum method (WSM) in the range between 1 and 10 on the basis of their percentage of contamination. The study shows that high and very high fluoride content (3.52–5.50 mg/l and more than 5.50 mg/l) is found in the undulating plateau with dissected valley while granite gneiss and pegmatite are the dominant fluoride bearing rocks. Fluoride minerals are being released from structural weak zones through various mobile agents and ultimately mixed into the soils and groundwater. The high and very high contaminated zones (37.79%) reveal moderate to good groundwater yield pockets of unconfined and semi-confined aquifers and larger population of these regions are exposed to fluoride vulnerability. [ABSTRACT FROM AUTHOR]

Water scarcity is a major problem for villagers' survival as it determines the population density and affects the migration pattern in Bara region. In the present study, groundwater resource endowment is studied and correlated with the distributional pattern of population, settlements and economic activity for analysing regional development in the study area. The study has been carried out using geospatial platforms, i.e. Erdas Imagine 2014 and ArcGis 10.2.2 software. Sentinel-2 satellite imagery and Cartosat-1 DEM data were the major data sources for extracting factor layers. Geomorphology and lineament maps of NRSC, District Resource Map of GSI, topographic maps and Google Earth images along with field surveys were ancillary database. Saaty's 9-point rating scale of analytical hierarchy process was used to extract the GWPI by integrating factor layers of geomorphology, lineament density, slope, geology, rainfall, drainage density and land use land cover according to their relative influence. Final map shows different zones of groundwater prospects in the study region, which is validated from aquifer thickness data. Result shows that 39.19% (291.41 km2) of the total area (743.64 km2) is classified as high-to-excellent GWP, whereas 27.96% (207.89 km2) of the area is under very poor-to-poor GWP. Areas having poor-to-poorest groundwater storage impact on population distribution, as 14% of the total population is lying over these zones. The descriptive statistical analysis showed that CGWPI and built-up area are significantly correlated (F = 18.024 > 4.41*, t = − 4.245 > 2.101, R2 = 50.03%). CGWPI is also correlated significantly with population density (F = 18.855 > 4.41*, t = -4.342 > 2.101, R2 = 50.16%). However, the relationship is not very high on linear regression model as expected since only 50% variations in population distribution can be attributed to CGWPI, for example, the Shankargarh town having the highest population density and the second highest built-up percentage in the whole study area in spite of being endowed with the lowest groundwater potential. [ABSTRACT FROM AUTHOR]

This study aims to identify and analyze the sediment connectivity in the Duas Bocas River watershed (BHRDB), in the Metropolitan Region of Greater Vitória (RMGV/Brazil), for the year 2019 and simulate an environmental degradation scenario for the watershed. For the modeling of sediment connectivity, a land use and land cover map from 2019 was used, followed by an environmental degradation scenario where the Atlantic Forest was replaced by exposed soil. The digital elevation model has a spatial resolution of 5 × 5m. The Index of Connectivity (IC) for the year 2019 ranged from −11.32 to 0.49, with lower values in the upper portion of the watershed, which is protected by the Atlantic Forest vegetation, minimizing the possibility of sediment production and transfer to the river. Regarding the environmental degradation scenario, the IC ranged from −11.32 to 1.68, with the highest IC occurring in the area of exposed soil in the upper portion of the watershed that was previously protected by the Atlantic Forest. It was also found that the estimation of IC is sensitive to the spatial resolution of the digital elevation model, making it challenging to assess the plain area near the outlet of BHRDB. The geospatial variability of sediment connectivity highlighted the importance of maintaining forests in headwater areas in relation to soil degradation in tropical environments. The IC proved to be an important tool for developing environmental scenarios, contributing to the management and environmental planning of watershed. • This work has undergone language revision and interpretations of the data, aiming to highlight the role of tropical forests, particularly the Atlantic Forest, in the process of connectivity in hydrographic basins. The goal is to provide support to planning and management bodies, emphasizing the importance of environmental preservation. [ABSTRACT FROM AUTHOR]

In this paper, we studied the geo-hydrological structure and behavior of a reference catchment, located in the Cilento UNESCO Global Geopark, southern Italy, representative of the hilly, terrigenous and forested headwaters of the Mediterranean eco-region. Based on detailed hydrogeological and hydro-geomorphological surveys and geomorphometric analysis, starting in 2012, a hydro-chemical monitoring activity at the catchment and sub-catchment scale started, and a hydro-chemical dataset was progressively recorded at daily and sub-hourly time steps. Based on this dataset, the authors performed an original procedure to identify different runoff components, derived by applying cascade mass balance filtering. The integration of hydrological and geomorphological approaches allowed us to obtain an interesting conceptualization of the storm flow generation using hydro-chemical signatures related to different runoff components produced during the increasing–decreasing cycle of the flood event magnitude. The hydro-system activated progressively different runoff sources (i.e., groundwater, riparian corridor, hillslope and hollow) and involved various mechanisms (i.e., groundwater ridging, saturation-excess, infiltration-excess and soil pipe exfiltration). The geo-hydrological conceptualization was validated using a hysteresis Q-EC loop analysis performed on selected events that showed how hysteretic indices could be used to characterize the events in respect to their origins, mechanisms and pathways in similar catchments.

Acid mine drainage (AMD) discharge has severe, long lasting impacts on water quality and stream ecology in affected watersheds due in part to the dynamic relationship between toxic metals (e.g. Al, Mn, and Cu) and Fe(III) oxy-hydroxides. Localized areas of biogeochemical activity that can mediate mineralogical transformation changes and cause metal release are potentially linked to stream geomorphology. This relationship has not been previously considered with respect to potential longitudinal variation within an impacted stream. The current work aims to determine how Fe(III) (oxy)-hydroxide speciation and distribution, and pore water chemistry in an AMD-impacted streambed, are affected by the presence of two geomorphic structures (a debris dam and step-pool sequence) in an Ohio watershed impacted by historical coal mining. In terms of solid phase mineralogy and geochemistry, in both the tributary and main stem, goethite was the dominant Fe-bearing phase throughout the AMD deposit depth in cores taken upstream of the geomorphic structures, whereas poorly-crystalline phases dominated downstream of the structures, despite the presence of Fe in the reducible fraction. The concentrations and distribution of extractable Al, Mn, and Cu were also different upstream versus downstream of each structure. Pore water Fe and Mn concentrations were higher downstream of the structures than upstream. Strong downward hydraulic gradients were present above the debris dam and in step-pool 1, whereas weaker upward hydraulic gradients were present below the debris dam and in step-pool 2. This work highlights that AMD deposit speciation and distribution, and pore water chemistry, are not spatially uniform within stream reaches, potentially as a result of groundwater-stream exchange-facilitated interactions in the presence of AMD-derived materials.

Tidal marsh (re)creation on formerly embanked land is increasingly executed along estuaries and coasts in Europe and the USA, either by restoring complete or by reduced tidal exchange. Ecosystem functioning and services are largely affected by the hydro-geomorphologic development of these areas. For natural marshes, the latter is known to be steered by feedbacks between tidal inundation and sediment accretion, allowing marshes to reach and maintain an equilibrium elevation relative to the mean sea level. However, for marsh restoration sites, these feedbacks may be disturbed depending on the restoration design. This was investigated by comparing the inundation-elevation change feedbacks in a natural versus restoration site with reduced tidal exchange in the Scheldt estuary (Belgium). This study analyzes long-term (9 years) datasets on elevation change and tidal inundation properties to disentangle the different mechanisms behind this elevation-inundation feedback. Moreover, subsequent changes in sediment properties that may affect this feedback were explored. In the restoration area with reduced tidal exchange, we found a different elevation-inundation feedback than on natural marshes, which is a positive feedback on initially high sites (i.e., sediment accretion leads to increasing inundation, hence causing accelerating sediment accretion rates) and a gradual silting up of the whole area. Furthermore, there is evidence for the presence of a relict consolidated sediment layer. Consequently, shallow subsidence is less likely to occur. Although short-term ecological development of the tidal marsh was not impeded, long-term habitat development may be affected by the differences in hydro-geomorphological interactions. An increase of inundation frequency on the initially high sites may cause inhibition of habitat succession or even reversed succession. Over time, the climax state of the restoration area may be different compared to natural marshes. Moreover, sediment-related ecosystem services, such as nutrient and carbon burial, may be positively influenced because of continuing sedimentation, although flood water storage potential will decrease with increasing elevation. Depending on the restoration goals, ecosystem trajectories and delivery of ecosystem services can be controlled by adaptive management of the tidal volume entering the restoration area. [ABSTRACT FROM AUTHOR]

The hydro-geomorphology of mountain catchments is mainly determined by vegetation cover. This study was carried out to analyse the impact of vegetation cover dynamics on flooding and water balance in 11 steep (0.27-0.65 m m-1) catchments of the western Rift Valley escarpment of Northern Ethiopia, an area that experienced severe deforestation and degradation until the first half of the 1980s and considerable reforestation thereafter. Land cover change analysis was carried out using aerial photos (1936,1965 and 1986) and Google Earth imaging (2005 and 2014). Peak discharge heights of 332 events and the median diameter of the 10 coarsest bedload particles (Max10) moved in each event in three rainy seasons (2012-2014) were monitored. The result indicates a strong reduction in flooding (R2 = 0.85, P<0.01) and bedload sediment supply (R2 = 0.58, P<0.05) with increasing vegetation cover. Overall, this study demonstrates that in reforesting steep tropical mountain catchments, magnitude of flooding, water balance and bedload movement is strongly determined by vegetation cover dynamics. [ABSTRACT FROM AUTHOR]

Physical-based soil erosion models are playing an important role in the assessment of soil erosion, transportation, and deposition in the watershed. Most of these models were developed for data-rich areas of the world and they need a measured data to calibrate and validate their results. To apply such physical-based models, the main factor hindering is the lack of measured sediment data. The amount of sediment in the fluvial systems is the result of hydro-geomorphological processes of a watershed and the nature of stream flows. Therefore, this study aims to develop an alternative empirical model that generates the observed sediment data based on the hydro-geomorphology and nature of stream flows for Ziway Lake basin in the rift Valley of Ethiopia. By applying Soil and water Assessment Tool (SWAT), the lake basin was divided in to two sub-basins (Maki and Katar) with 26 of the watersheds within Maki. The SWAT model was calibrated and validated for both stream and sediment flow by using SUFI-2 program and its performance was assessed by using model evaluation statistics. With calibrated sediment flow rates of 26 Maki sub basins, an empirical model was developed by using its respective drainage area, average sub-basins slope, surface runoff, soil erodibility factor, stream flow rate, and average rive slopes. The applicability of the newly developed alternative model was tested by using model evaluation statistics and validated inside of Katar sub-basin. It is recommended to test the developed model in other basins to incorporate with SWAT CUP program to calibrate and validate the sediment yield at data scared area.

Riparian ecosystems are defined by the nature and regularity of the interactions between a given river system and its floodplains, and past studies have often presented vegetation cover as the exclusive expression of these interactions. There has been to our knowledge, no systematic attempt at linking greenhouse gases (GHG) fluxes and types of riparian buffers. The present study was conducted to investigate the intensity and seasonality of carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) fluxes in riparian buffers in three common hydro-geomorphic settings (HGM) across the White River watershed (Indiana, USA). These classes included riparian sites located: (i) in till plain depressions near 1st order streams (HGM-1), (ii) in incised narrow valleys with thin alluvium layers above glacial till (HGM-2), and (iii) along 3rd–4th order streams in broad floodplains with thick alluvial and glacial outwash deposits (HGM-3). For each class, 3 sites were selected and GHG fluxes were measured during the wet (May) and dry seasons (August). Strong relationships were found between GHG fluxes, soil properties and environmental factors, but these relationships varied with season and gas species, making it challenging to rely on these relationships for GHG fluxes upscaling. Analysis of variance and discriminant analysis showed that the HGM-defined riparian buffers were distinct in terms of GHG flux intensity. Regardless of season, the HGM-1 sites emitted CO 2 at rates 1.6 times higher than at the other sites, likely due to difference in soil C quality. During the wet season, N 2 O emission was significantly higher at the HGM-3 than at the other sites (0.88 vs 0.27 mg N m − 2 d − 1 ), and was negatively related with the gradient of the adjacent channel (r 2 : 0.69). The riparian buffers acted as CH 4 sinks, with the HGM-2 sites exhibiting CH 4 uptake rates significantly greater than the other riparian types (− 0.80 vs − 0.34 mg CH 4 -C m − 2 d − 1 ). The consistency of these results underscores the potential of an HGM-based monitoring approach to derive watershed-scale GHG budgets for riparian buffers. [ABSTRACT FROM AUTHOR]

Wetlands are one of the most important ecological environments that also have high socio-economic importance. India hosts a large number of wetlands, among which most are in the Indo-Gangetic Plains formed by riverine processes. In order to understand the extensive system of riverine wetlands and their distinction from other floodplain water bodies, mainly the waterlogged areas, a mapping and classification system has been proposed and applied for wetlands in the Begusarai district of north Bihar plains, India. The proposed hydro-geomorphic classification system is hierarchical, simple, and robust, and can be implemented through quick processing of satellite images integrated with minimal ancillary data. [ABSTRACT FROM AUTHOR]

Digapahandi block of Ganjam district is a chronically drought prone and economically backward area of Odisha. The agricultural lands which are mostly rain fed bear the adverse effects of drought resulting in loss of crops. Surface water irrigation is very limited and not dependable due to vagaries of monsoon rainfall. Drinking water problem is very acute during summer as most of the wells go dry. Keeping this fact in view the research was aimed at locating site specific artificial recharge structures for groundwater resource conservation and augmentation in hard rock terrain. Satellite IRS- IC LISS III data have been used to prepare various thematic maps. The study reveals that the major litho units are granitic gneisses, khondalite and charnockite suite of rocks. The geomorphic units are pediplain, flood plain, denudational and structural hills. Four sets of lineaments have been identified. The trends of lineaments are broadly NE-SW, NNE-SSW, NW-SE and N-S. The interpreted data is cross-checked and confirmed during field visits. Based on the hydro-geological set-up, suitable site- specific artificial recharge structures such as percolation tank, check dam, contour bund, gully plug and vegetative measures have been suggested to maintain the balance between the recharge and draft. [ABSTRACT FROM AUTHOR]

Species turnover is a central issue in plant ecology and has a high significance in conservation of biodiversity and ecosystem management. Niche differentiation and dispersal limitation are the two main processes controlling species turnover of upland vegetation. However, our understanding of the drivers of plant species turnover in wetlands remains poor. To comprehensively disentangle the influences of niche differentiation and dispersal limitation on the plant species turnover in wetlands of the Great Hing’an Mountain valleys, we not only considered two plant functional groups (herbs and shrubs), but also took hydro-geomorphological variables into account when quantifying the effect of environmental differences on species turnover. We found that species similarity, measured by the Jaccard similarity index, decreased with geographic distance for both herbs and shrubs with a decay rate being −0.39 and −0.49, respectively. We then partitioned the variance of species similarity based on type III sums of squares in partial correlations. Results showed that geographic distance and the joint effect were the most important factor explaining the species turnover of herbs and shrubs respectively when representing environmental constraints with climatic variables only. The total explained variances were improved by 15.93% for herbs and 24.69% for shrubs after including hydro-geomorphologic measurements. Our study showed that both dispersal limitation (represented by geographic distance effects) and niche differentiation (represented by climate and hydro-geomorphology) played important roles in shaping wetland species turnover, but their relative effects differed by plant functional groups. Considering hydro-geomorphological characteristics can better elucidate the role of the environment in shaping species turnover in wetland systems than using climatic variables alone. [ABSTRACT FROM AUTHOR]

This paper presents a new methodology for the zoning of littoral sand barriers on the basis of their groundwater dynamic responses to the local mean water level (MWL) climate. The method is based on the comparison of the characteristic scales of the horizontal drainage and recharge processes. Using the Boussinesq equation and basic hydro-geomorphological parameters, this methodology identifies the climatic events that markedly affect the groundwater dynamics across the barrier, along with the location of the most affected cross sections. The application of the methodology to the Mar Menor sand barrier shows that a significant number of cross sections can be particularly vulnerable to the effects of local storm events typical of the Mediterranean coast during the spring and winter seasons. The location of the affected cross sections is analyzed as a function of both the local MWL forcing and hydrogeological parameters. This case study highlights the possible use of the proposed methodology for land use planning and the environmentalmanagement of coastal sand bars. [ABSTRACT FROM AUTHOR]

The hydraulic management of large rivers led to a disconnection of side-channels. Restoration works were to reconnect these side-channels to the main course in order to recover hydrological and ecological functions. The aim of the study was to analyze the vegetation dynamics after restoration and to link it to the change in chemical and hydro-geomorphological characteristics. Changes in species richness, cover and composition of the macrophytes communities were studied in nine side-channels of the Rhine river (France) after reconnection which occurred between 1998 and 2006. Vegetation dynamics was surveyed between 2007 and 2011 and compared to the ones of three target side-channels (never disconnected). Three vegetation communities were identified: one characterized by rheophilic species, a second one by mesotrophic species, and a third one by eutrophic species. Distribution of communities depended mainly on the flow velocity and the sediment texture of the side-channels. The floristic composition of communities evolved rapidly and remained stable a few years after restoration. Changes in species richness and cover remained relatively low in all side-channels over the study period. Time after restoration did not affect the dynamics of colonization. Reconnection allowed the restored side-channels to exhibit vegetation dynamics similar to those of the target side-channels. [ABSTRACT FROM AUTHOR]

Abstract: Floodplains in Europe are heavily impacted by human intervention and often disconnected from the main river channel. Restoring lateral hydraulic connectivity between wetlands, fringe habitats and riparian land with the adjacent river channel is extremely important to maintain natural functioning of floodplain wetlands. However, there is no simple solution to restoring and rehabilitating rivers and their floodplains, particularly in terms of long-term sustainability. Floodplains are often the most fertile and productive part of the landscape, in terms of both agricultural production and natural ecosystems. Restoration projects must be able to balance conflicting needs and interests. Flood management is one of the most powerful drivers of developing strategies for floodplain restoration. Appropriate restoration management of floodplains is vital for the conservation of unique bio-diverse systems and for sustainable agricultural productivity. By developing strategies that better incorporate floodplain restoration in the context of the basin scale, it will become more feasible to develop the most effective restoration actions for a specific river type and location. Within this context we must not forget that successful natural resource management is much more than developing good science; it requires working with landowners, meeting deadlines, securing funding, supervising staff, and cooperating with politicians. Furthermore, the benefits of floodplain restoration must be equally demonstrated for multiple purposes including a range of ecosystem services. This paper explores the various interactions associated with floodplain dynamics. Through case studies it explores the various approaches that have been taken across Europe to forward the restoration of these fragile and important ecosystems and embeds these in the context of current European environmental policy and directives. [Copyright &y& Elsevier]

This paper presents a synopsis of the findings of a valley bottom wetland monitoring study in which dominant hydrological processes maintaining the system are quantitatively defined. The Craigieburn-Manalana is a wetland subjected to technical rehabilitation, at the headwaters of the Sand River in the lowveld savanna region of South Africa. Findings include the identification of a rapid water delivery mechanism from the surrounding hillslopes to the wetland following a threshold-exceeding precipitation event, when hillslope-toe soil matric potential is close to 0, leading to a raising of the wetland water table by >0.7 m within 3 h. A summary of quantified fluxes and associated water budget of the wetland and its contributing catchment is developed. It is revealed that this wetland does not necessarily conform to the typical assumptions that wetlands augment low flows. Surface layer scintillometry shows actual wetland evapotranspiration to dominate the water budget during the dry season (2.3-3.5 mm/d) compared to its contributing catchment (0.9-2.2 mm/d), whilst stream discharge had ceased. Hydrograph separation, based on stable isotopes (18O), revealed that the wetland does not attenuate peak flows during the summer rains when the wetlands soil moisture deficit is close to 0, since more than 66% of stream discharge comprised event water. These results are discussed within the context of current hydrological understanding of southern African headwater wetlands, such as dambos. [ABSTRACT FROM AUTHOR]

Abstract: The study highlights the relevance of integrating hydro-geomorphological typologies in pluri-disciplinary ecological researches on ecosystem functioning, in two contrasted hydrosystems: the Rhine alluvial plain and the Yzeron basin. Two hydro-geomorphological typologies of reference status in rivers, elaborated from the same conceptual scheme, are compared with two bio-typologies of ecosystem functioning characterization, one based on communities of aquatic macrophytes (Rhine plain) and the second on oligochaete assemblages (Yzeron basin). The two bio-typologies mainly reflect water exchanges between surface water and groundwater. In the Rhine plain, morphodynamics of the D3 geomorpho-type modify the tendency of increasing in the trophic level from upstream to downstream areas, this increasing being only verified for the D4 geomorpho-type. Indeed, morphodynamics of the D3 geomorpho-type prevents channel clogging and activates the limnocrene groundwater springs, inducing water oligotrophication and increase of biodiversity. In the Yzeron basin, which is impacted by polluted urban water runoffs, the B3 and A1 geomorpho-types present the highest values of ecological potentials (EPs) due to greater slopes and active surface water/groundwater exchanges. Results suggest that some biological characteristics and ecological functions could be spatialized on larger spatial scales through appropriate geomorphic river typologies. [Copyright &y& Elsevier]

Lake sediment and geomorphic evidence from the Loch of the Lowes/St Mary's Loch basin in the central Southern Uplands of Scotland provide a multiproxy reconstruction of changing sediment availability and transmission through the catchment. Interrogation of magnetic, geochemical and grain size parameters for lake and catchment materials suggests it is possible to identify independent proxies that reflect both supply (availability) and discharge (capacity) controls on the sediment signal. Chronological control for the lake sediment record is proposed by linking a 210Pb/137Cs chronology for the last c. 120 yr to an age/depth profile based on proposed temporal correlations between cyclic HIRM/χLF variability and the North Atlantic Oscillation. Geochronological studies on debris cones and alluvial fans yield evidence for episodic hillslope gullying ∼2000-0 BC with more extensive region-wide slope instability AD 700-900, 1100-1300 and after AD 1450-1550 and gully stabilization over the last 150 years. The latter two episodes coincide with the lake sediment evidence for increased sediment supply from ∼AD 1600 declining after ∼AD 1870. The capacity-related lake proxies appear to identify phases of increased flooding ∼AD 1625-1650, 1680-1700, 1730-1760, 1800-1815, 1850-1880, 1910-1930, 1960-1970 and possibly the 1990s. Close correspondence between the sediment 'flood' archive and historical records of flooding in Scotland suggests that lake-catchment systems of this type have the potential to yield valuable information on past hydrological response. [ABSTRACT FROM AUTHOR]

Ecological engineering is at a beginning stage in Korea, with its concept first introduced only in the early 1990s. Basic knowledge and experience of ecological engineering, mostly adapted from Germany, U.S.A. and Japan, have been applied to stream restoration. Since then, large-scale research and demonstration projects of stream restoration have been implemented by both the central and local governments. At present, ecological river engineers should concern instream flow, stream restoration, and hydro-geomorphic interaction induced by human activities including dams, gravel mining and channelization. Understanding the micro as well as macro interaction between flow, sediment, geomorphology, structure, and vegetation is essential for properly approaching the problems. In the near future, furthermore, it is needed to seriously consider removals of weirs/small dams and levees with their functions lost in order to make our society to remain safe against floods of seemingly increasing magnitude and frequency and restore the stream ecosystem degenerated by those flood defense structures as well. [ABSTRACT FROM AUTHOR]

The dolphins Inia geoffrensis—boto and Sotalia fluviatilis—tucuxi are threatened cetaceans inhabiting river ecosystems in South America; population numbers are still lacking for many areas. This paper provides density and abundance estimations of boto and tucuxi in 15 rivers sampled during the past nine years as part of a multinational research alliance. Visual boat-survey data collection protocols and analyses have been developed since 2012 (based on Distance Sampling methods) and recently reviewed (2019) to improve robustness and comparability. Differences across the sampled rivers and the analyzed river basins (Amazon and Orinoco) pointed to a density/population size gradient with lower densities and abundances observed in the Orinoco basin (0.9–1.5 ind./km²), passing through the eastern Amazon basin (2–5 ind./km²), and the largest numbers found at the central Brazilian Amazon (lower Purus River—2012 (14.5 boto/km², N = 7672; 17.1 tucuxi/km², N = 9238)). However, in other parts of the central Amazon, the density of dolphins was smaller than expected for high productive whitewater rivers (1–1.7 ind./km² in the Japurá and Solimões rivers). We attributed these differences to specific features of the basin (e.g., hydro-geomorphology) as well as to the cumulative effects of anthropogenic activities. [ABSTRACT FROM AUTHOR]

Stream ecosystem metabolism plays a critical role in planetary biogeochemical cycling. Stream benthic habitat complexity and the available surface area for microbes relative to the free-flowing water volume are thought to be important determinants of ecosystem metabolism. Unfortunately, the engineered deepening and straightening of streams for drainage purposes could compromise stream natural services. Stream channel complexity may be quantitatively expressed with hydraulic parameters such as water transient storage, storage residence time, and water spiralling length. The temperature dependence of whole stream ecosystem respiration (ER), gross primary productivity (GPP) and net ecosystem production (NEP = GPP − ER) has recently been evaluated with a “natural experiment” in Icelandic geothermal streams along a 5–25 °C temperature gradient. There remained, however, a substantial amount of unexplained variability in the statistical models, which may be explained by hydraulic parameters found to be unrelated to temperature. We also specifically tested the additional and predicted synergistic effects of water transient storage and temperature on ER, using novel, more accurate, methods. Both ER and GPP were highly related to water transient storage (or water spiralling length) but not to the storage residence time. While there was an additional effect of water transient storage and temperature on ER (r2 = 0.57; P = 0.015), GPP was more related to water transient storage than temperature. The predicted synergistic effect could not be confirmed, most likely due to data limitation. Our interpretation, based on causal statistical modelling, is that the metabolic balance of streams (NEP) was primarily determined by the temperature dependence of respiration. Further field and experimental work is required to test the predicted synergistic effect on ER. Meanwhile, since higher metabolic activities allow for higher pollutant degradation or uptake, river restoration and management should promote habitat diversity and complexity (hyporheic zone, macrophyte patches, substrate heterogeneity), especially for microbial activity.