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A variety of hierarchical gene flow models have been proposed to explain the distribution of genetic variation in aquatic environments. These models, including the Stream Hierarchy (SH), Death Valley (DV), Headwater (HW), and Widespread Gene flow (WG) models, provide testable hypotheses that focus on the degree of within-basin or within-stream network connectivity and an organism's dispersal abilities. We tested these models using Tlaloc hildebrandi (Profundulidae, Cyprinodontiformes), a freshwater fish endemic to the highlands of the Grijalva and Usumacinta River basins in southern Mexico. Data from ultraconserved elements (UCEs) showed that although T. hildebrandi was recovered as monophyletic, the sub-basins were not. We generated single nucleotide polymorphisms from the UCEs to analyse the data in a population genetic framework. These results differed between analyses such that two (STRUCTURE analysis) or three (DAPC analysis) genetic groupings were recovered. Overall, the results of this study provide support for the SH model. Some individuals from the Jataté sub-basin, however, conformed to the HW model, due to historical connections among headwater streams and rivers of the Jataté and Amarillo–Chenalhó clades/clusters. The greatest degree of gene flow has occurred from the Grijlava to the Usumacinta basins, two geographically proximate basins that have been hypothesized to have had previous connections. [ABSTRACT FROM AUTHOR]

Fish assemblages in freshwater ecosystems are becoming more homogenous from multiple abiotic, environmental, and physicochemical variables at different scales. Historical fish collections (1976–1977) by Billy Michael Johnson and Dr. Johnson K. Beadles were compared to contemporary fish collections (2018–2019) in tributaries of the Eleven Point River basin in Arkansas to examine patterns of fish assemblage change. Fish assemblage change variables were compared to pasture land use/land cover (LULC) at multiple scales and in‐stream habitat variables to understand relationships and discover potential correlates suggesting biotic homogenization. Fish assemblages in the Eleven Point River basin of Arkansas have experienced significant spatiotemporal changes, and LULC change and habitat alterations may have influenced this process. Increased tolerant species and decreased intolerant species at sites contributed to biotic homogenization, particularly in pool habitats. Surprisingly, expansion of some intolerant fishes was also observed that tend to occupy riffles. Sites with high percentages of pasture LULC at finer spatial scales typically had more homogenised fish assemblages. We hypothesized gravel aggradation from local pasture land use has degraded pools and increased riffle habitat, resulting in homogenised fish assemblages in the Eleven Point River basin over the study period. Few studies link LULC, in‐stream habitat, and biotic homogenization when examining fish assemblage change over time, and these dynamics can be particularly complex in upland streams experiencing gravel aggradation. Similar research in other upland, gravel‐bed river systems would provide a broad understanding of the presented environmental associations. [ABSTRACT FROM AUTHOR]

Walleye, Sander vitreus, has several distinct genetic lineages throughout North America as a consequence of Pleistocene glaciation. Stocking walleye across genetic boundaries in the mid-20th century has led to the introduction of non-native strains that persist to this day. In West Virginia, the identification of the native Eastern Highlands strain led the West Virginia Division of Natural Resources (WVDNR) to employ broodstock screening to assist in the conservation of the native strain. To develop a baseline native ancestry prevalence in walleye populations throughout the state, 1532 broodstock were sampled across 17 sampling locations over a 6-year period. To evaluate the effectiveness of the current broodstock two-SNP qPCR assay protocol and identify whether more SNPs need to be implemented, 284 walleye were sequenced and ancestry-genotyped across 42 fixed SNPs between the two strains. When comparing the current protocol to the older microsatellite protocol, advancement in the ability to identify native-strain individuals was observed. Genotyping previously assigned walleye broodstock across multiple fixed SNPs revealed that the current ancestry assignment protocol, on average, assigned individuals that display 96% Eastern Highlands native ancestry to the native strain and accurately identified >93% of all pure Eastern Highlands walleye. Throughout the state of West Virginia, the New and Kanawha River systems contained a high prevalence of native ancestry, with the Ohio River and sampled impoundments displaying varying levels of ancestry. SNPs with >98% prevalence in individuals assigned to the Eastern Highlands strain were identified during the course of the study and can be implemented in future screening protocols. Our results highlight the utility of genomic approaches as tools to assist fisheries management goals and their capability to accurately identify native ancestry to assist in conservation efforts. [ABSTRACT FROM AUTHOR]

This study examines drought patterns in Ethiopia's 12 major river basins from 1981 to 2018 using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Both indices reveal historical drought episodes with slight variations, with significant differences in 1984, 2009, and 2015. Except for the Wabi-Shebelle catchment in southern Ethiopia, all river basins show an increasing trend in SPI12 and SPEI12 indices. The eastern and central regions experience more drought according to SPEI3. Seasonal correlations show that during the March-May rainy season, precipitation is negatively correlated with the Indian Ocean Dipole (IOD) index, while in the June-September season, it negatively correlates with Nino 3.4 and positively with IOD. The study also found that El Niño leads to less rainfall in the Ethiopian highlands, while La Niña results in more rainfall in the central and northern highlands but less in the south. [ABSTRACT FROM AUTHOR]

This study investigates impact of land use/cover change on water balance of River Mitano catchment in Southwestern Uganda using SWAT model. Land use/cover changes were assessed using three land use maps for years of 2000, 2010 and 2020. Water fluxes were simulated using observed daily discharge.14.4% of precipitation received is converted into discharge, with base flow (2.9%) and lateral flow (11.8%) major contributors. Conversion of grasslands to cropland and built-up areas were key changes. An increase in cropland (6.8%) and built-up areas (3.0%) at expense of grassland and wetland were noticed, with significant increase in monthly and annual groundwater flow. [ABSTRACT FROM AUTHOR]

Walleye is an important sportfish across eastern North America, is commercially fished in the Laurentian Great Lakes region, and has been introduced outside its native range. Thirty-eight Walleye populations within six watersheds across the Eastern Highlands and other portions of the native range were screened at eight microsatellite DNA loci to better understand evolutionary history and to inform fishery management and conservation efforts. Population genetic variation showed divergent assemblages of populations, respectively, living in the Mobile Bay, Mississippi River, Eastern Highlands (Tennessee, New, and Ohio Rivers), and Great Lakes drainages today. All estimates of effective numbers of breeding individuals were under 25, and all populations within all watersheds had ~15–20% inter-individual relatedness, likely attributable to the effects of both natural demographic processes and stocking. The extent of Eastern Highlands Walleye includes both the Ohio and Tennessee River basins. [ABSTRACT FROM AUTHOR]

This study investigated the effects of nonpoint source (NPS) pollution reduction and pollutant dynamics in a highland agricultural watershed in Korea. We employed the SWAT model to simulate hydrological processes and pollution transport within the watershed. The model incorporates future climatic scenarios derived from downscaled climate projections to assess their impacts on NPS pollution and pollutant reduction methods. These changes lead to heightened surface runoff and erosion rates, resulting in elevated sediment and nutrient concentrations. The projection indicates an anticipated increase in the annual average temperature by 1.3 to 2.1 °C by the mid-century, under scenarios SSP126 and SSP585. Additionally, precipitation levels are projected to increase by 31 to 61 mm from the baseline to the end of the century. Variations in hydrological components such as evapotranspiration, streamflow, and soil moisture are expected to range from +3.2 to +17.2%, −9.1 to +8.1%, and 0.1 to 0.7%, respectively, during the years 2040 and 2080. Fluctuations in TN, SS, and TP loading are estimated to range from −4.5 to +2.3%, −5.8 to +29.0%, and +3.7 to +17.4%, respectively. This study emphasizes the importance of adaptive management options for stakeholders and the need for adaptive management options to reduce nonpoint source pollution and protect water quality to maintain sustainable water supplies and conserve the environment in this watershed. [ABSTRACT FROM AUTHOR]

The hydrological cycle changes in the Loess Plateau have attracted a global attention due to the combination of climate, land use changes, and the implementation of gully consolidation and highland protection ( GCHP) project. The Soil and Water Assessment Tool ( SWAT) model and the China Meteorological Assimilation Driving Datasets (CMADS) were used to quantitatively analyse the effects of the GCHP project and four distinct land use scenarios on the evolution of the hydrological cycle in the Malian River basin. The results indicate that the SWAT and CMADS model effectively simulates the hydrological process changes in the basin. From 1995 to 2020, there was a decrease in the annual average runoff volume within the basin by 130. 875 0 million m³, representing a reduction of 4. 56% . Compared to the land use scenario in 2020, the average annual runoff in the scenario of converting all farmland back to forest / grassland in the basin decreased by 2. 838 0 million m³ and 19. 237 0 million m³, respectively while the average annual runoff in the scenario of GCHP project (gully head landfill) decreased by 11. 353 0 million m³. The simulation study on the impact of GCHP project and land use changes on runoff in the Malian River basin has significant practical implications for ecological environment protection and sustainable development. [ABSTRACT FROM AUTHOR]

Large‐scale cross‐site scientific synthesis on low‐flow storage–discharge relation can promote developing transferable hypotheses on the interactions among critical zone attributes and on how such interactions affect catchments' water vulnerabilities. This study leverages cross‐site empirical and theoretical analyses and develops a similarity index, based on the interactions among critical zone attributes, to help determine the less‐explored influence of upland hillslope groundwater subsidy on storage–discharge relation. We show that an increase in the relative extent of upland hillslope groundwater subsidy to low‐flow discharge, occurring through deep slow low‐moving (e.g., bedrock) storage unit, leads to (a) an increase in the nonlinearity of low‐flow discharge sensitivity to storage (β1) and (b) an increase in the convexity of low‐flow storage–discharge relation. Our findings also raise new hypotheses on the applicability of Boussinesq‐based hydraulic groundwater theory at low‐flow condition. Empirical results show that in a portion of our study catchments, particularly in those with a relatively small extent of upland hillslope groundwater subsidy, the theory's proposed range of nonlinearity sufficiently explains the nonlinearity of low‐flow storage–discharge relation. However, in catchments with a strong influence of upland hillslope groundwater subsidy through deep slow‐moving storage unit, the current state of hydraulic groundwater theory, using one single (non)linear representative storage unit, may not be sufficient to explain the large nonlinearity and convexity of low‐flow storage–discharge relation (or the long tail of hydrograph late recession). Considering β1 informs the low‐flow vulnerability of catchments, the findings of this study deepen and generalize our understanding of where low‐flow discharge is vulnerable to storage's change. Plain Language Summary: There is limited knowledge of the ways watersheds generate stream low flow during dry periods, in watersheds with no (or little) streamflow observations and even in watersheds with extensive streamflow observations. This knowledge gap can limit the development of accurate models and hinder assessments of the impacts of global environmental changes on drought vulnerability. This study aims to address this knowledge gap by examining the a less‐explored way in which watersheds may generate a large amount of streamflow during dry periods from upland hillslopes located tens to hundreds of kilometers away from the mainstream. Our study shows that in some environments, this poorly quantified component of water balance may disproportionately (a) affect the relationship between watershed storage and streamflow discharge, which is used to develop a hydrologic model, and (b) contribute to the long tail of streamflow hydrograph during dry periods and thus reducing the vulnerability of drought. Our findings suggest that while the classical theory of streamflow generation can sufficiently explain the ways watersheds generate stream low flow in a portion of watersheds, the large contribution from upland hillslopes to low flow may result in certain watersheds being less low‐flow vulnerable than others. Key Points: Upland hillslope groundwater subsidy increases the nonlinearity of low‐flow dynamics and alters the shape of storage–discharge relationHydraulic groundwater theory explains the estimated low‐flow nonlinearity in a portion (but not all) of the study catchmentsCatchments with a limited extent of upland hillslope groundwater subsidy may be more low‐flow vulnerable than catchments with a larger upland subsidy [ABSTRACT FROM AUTHOR]

The Gully Consolidation and Highland Protection (GCHP) project is crucial in preventing gully erosion in the Loess Plateau. However, there are new problems after the completion of the GCHP project, such as secondary disasters caused by sudden changes in water flow paths. To study the impact of different GCHP measures on runoff and sediment production, we conducted a series of scouring experiments using the similarity principle, taking Fengbao Gully, Xifeng District, Qingyang City, Gansu Province, as a prototype. Moreover, three scenarios in the GCHP project (landfill (LT), nondrained terraced (NDT), and terrace with a drainage system (DT)) are established. Seasonal rainfall simulation experiments are conducted with a constant slope. The results showed that during summer rainfall, the 10 min runoff depth of LT is 67.83~276.03% higher than that of NDT. However, in spring and autumn, the runoff depth of NDT is 4.12~39.84% higher than LT's. The sediment yield of LT is 0.06–5.58 times higher than that of NDT and 1.91–25.58 times higher than that of DT. The sediment yield of NDT is 0.46–4.02 times higher than that of LT and 2.27–23.93 times higher than that of DT, indicating that, under the same conditions, the effect of slope replacement with terraces for GCHP is better than that of gully head landfill in reducing soil erosion and secondary geological disasters. Furthermore, imperfect terrace construction can result in increased sediment yield. This study provides a scientific basis for the maintenance and later management of GCHP and helps implement soil and water conservation measures in similar regions worldwide. [ABSTRACT FROM AUTHOR]

Slash‐and‐burn agriculture is an important driver of tropical forest loss and typically results in a mosaic of land uses. However, there is little quantitative information about the hydrological effects of long‐term slash‐and‐burn agriculture and how such mosaics affect the rainfall‐runoff response at the catchment scale. We monitored streamflow responses at two points along a perennial stream in a 31.7 ha catchment in eastern Madagascar that was monitored previously between 1963 and 1972. Land cover in 2015 consisted of degraded grasslands, shrub and tree fallows at various stages of regrowth (64%), eucalypt stands for charcoal production (30%), and rice paddies and wetlands in the valley‐bottom (3%). For the majority (60%) of the events during the study period, the ratio between the total amount of stormflow and rainfall was <3%, suggesting that for these events runoff was generated in the valley‐bottom only. Events for which an antecedent soil moisture storage plus rainfall (ASI + P) threshold was exceeded had much higher stormflow ratios (up to 50%), indicating that a certain wetness was required for the hillslopes to contribute to stormflow. Stable isotope sampling for four small to moderate events indicated that stormflow was dominated by pre‐event water. Total stormflow and annual water yield in 2015 were higher than in the 1960s, despite much lower rainfall in 2015. We attribute these differences to changes in soil physical properties caused by the repeated burning and loss of top‐soil, which has resulted in a reduction in the depth to the impeding layer. The changed runoff‐processes (less infiltration, more saturation‐excess overland flow) thus affect local water resources. [ABSTRACT FROM AUTHOR]

SWAT+ is a revised version of the SWAT model that has the capability to route flow across landscape units in the catchment, which is expected to improve the spatial representation of processes in watersheds. We applied the SWAT+ model in the Uruguay River Basin, an international river basin in South America with a total surface area of 370,000 km2, in order to (1) assess the water balance components, (2) represent their spatial distribution, and (3) examine their changes over time. The catchment was divided into uplands and floodplains and a decision table rule was developed based on streamflow data. The SPOTPY Python library was linked to SWAT+ and used as a tool to perform sensitivity analyses and calibration. The model represented the fluctuations of discharge well, although there was a general tendency to underestimate peak flows. Blue (precipitation and runoff) and green (evapotranspiration and soil water content) hydrological components were spatially plotted. Overall, SWAT+ simulated a realistic spatial distribution of the water cycle components. A seasonal Mann–Kendall test suggests a positive increasing trend in the average temperature (p-value = 0.007; Sen's slope = 0.09), the soil water content (p-value = 0.02; Sen's slope = 1.29), and evapotranspiration (p-value: 0.03; Sen's slope = 1.97), indicating that the ecosystem experienced a changing climate during the simulation period. The findings presented in this study are of significant value for the impacts of sustainable management and the evaluation of climate change on water resources in the Uruguay River Basin. [ABSTRACT FROM AUTHOR]

Understanding soil qualities related to land use and landscape positions is critical for designing long term soil management practices. The research was set out with the objective of analyzing the effect of land use and landscape positions on selected soil physicochemical properties in Dire watershed, central highland Ethiopia. Replicated 27 composite surface soil samples were collected across three landscape positions from three land use types (cultivated land, grazing land and forest land) and analyzed using standard protocols. Results showed that land use type, altitude and slope significantly affect important soil physicochemical properties. These include particle size distribution, bulk density (BD), electrical conductivity (EC), soil pH, available water content (AWC), permanent wilting point (PWP), field capacity, soil organic carbon (SOC), total Nitrogen (TN) and available phosphorus (AP). Analysis of variance results showed that significant (p < 0.05) effect of slope, land use, landscape position and their interaction on AP, SOM, SOC, PWP and AWC. Results of correlation analysis showed that SOC, and EC have a significant positive correlation with TN but, AP, TN, and clay content were negatively correlated with BD. Comparatively cultivated land recorded lower soil quality than forest and grazing lands. [ABSTRACT FROM AUTHOR]

Functional traits of river fish assemblages have rarely been studied in the Eastern Mediterranean region. A dataset of 254 Greek electrofished near-natural sites (427 samples) was analyzed to explore native fish functional structure across three spatial scales: (a) among six ecoregions, (b) within a single ecoregion, and (c) in a river basin. Overall, 76 native fish species were assigned eight functional categories, involving 24 different traits. Bipartite networks were used to interpret spatial patterns of species trait data. Two major trait assemblage types were detected in all three spatial scales: the upland type, dominated by insectivorous, benthic, rheophilic, intolerant species, and the lowland type, incorporating omnivorous, limnophilic, phytophilic, and tolerant species. In order to provide further insights between traits and key environmental variables, redundancy analysis (RDA) was employed. The RDA depicted a strong upstream–downstream environmental gradient. Upland and lowland assemblage types form two distinct functional zones along the upstream and downstream river stretches, respectively. Yet, no consistent boundary criteria seem to exist between them. Notably, within a region of high fish assemblage heterogeneity such as the Eastern Mediterranean, functional patterns follow well-established phenomena along the upstream–downstream longitudinal profile of temperate lotic waters. [ABSTRACT FROM AUTHOR]

Glacial cycles and pre-glacial drainage patterns have imbued the Interior Highlands of the United States with a rich suite of freshwater taxa and phylogroups. However, supplementation of sportfish from the Great Lakes into the waterbodies of this region, including the Missouri, Ouachita, Black, White, and Little Red River drainages, may have obscured phylogeographic patterns. Walleye (Sander vitreus), one of the most common sportfish in the eastern US, inhabit the Interior Highlands but their population genetic composition and structure in this region has received little attention. We examined the genetic composition of walleye (n = 643) in the Interior Highlands using microsatellite markers and a subsample (n = 188) with mitochondrial DNA and found significant genetic differences among walleye in our study area. Walleye from the Missouri, Ouachita, White, and Little Red drainages were most closely related to a Great Lakes reference sample, a common stocking source. However, the Black River, in the easternmost portion of the Interior Highlands, contained walleye with mitochondrial DNA that was closely related to walleye from the Eastern Highlands. The remainder of the study area drainages contained a mix of walleye groups, more closely related to Great Lakes rather than Highlands walleye but not definitively the product of stocking. Though managers have relied on mitochondrial markers for stock identification in the past, we recommend that walleye in regions receiving little research attention be analyzed with nuclear markers to better understand and preserve genetic diversity and that managers stock with local walleye only within the drainages that we identified as genetically distinct: Black, Missouri, and White/Little Red/Ouachita. [ABSTRACT FROM AUTHOR]

Lake Tana basin encompasses a wide regional volcanic aquifer system, in the northwestern highlands of Ethiopia. It has significant water resource potential for water supply and irrigation purposes. The objective of this study was to assess the physiochemical characteristics of the surface water-groundwater and investigate the processes controlling groundwater chemistry. A total of 273 water samples were collected from different water points for major ions and stable isotope analysis, representing different physiographic and hydrogeologic regions. Multivariate statistical, graphical methods, saturation and speciation modelling were used jointly to characterize water chemistry and to define hydrogeochemical processes. The Piper plots in combination with cluster analysis and isotope hydrological data indicate that, generally, the groundwater chemistry of the basin can be classified into (1) low TDS Ca-HCO3, Ca-Mg-HCO3, and Ca-Na-Mg-HCO3 type water which is relatively enriched in δ18O-δ2H and depleted in δ13C. These are recharge waters, which are characterized by low rock-water interaction; (2) brackish Mg-Na-Ca-HCO3 type water which is relatively depleted in δ18O-δ2H and enriched in δ13C; and (3) low TDS Na-(Ca)-HCO3 and Na-HCO3 type water which varies from less to more depleted in δ18O-δ2H and is characterized by relatively enriched δ13C. The cross-plots of the major cations vs. HCO3− and stability diagrams show that the primary processes controlling the groundwater evolution in the Lake Tana basin are alumino-silicate weathering and dissolution. Studying the hydrogeochemical characteristics of a complex geologic system with integrated approach helps to understand the complex groundwater flow system and flow dynamics, which in turn helps for proper groundwater utilization and future management. [ABSTRACT FROM AUTHOR]

Archaeologists frequently invoke climate change as a driving cause for ancient expansions of human populations, but geomorphic changes can also play an important role in opening or closing routes of migration. In China, archaeological evidence demonstrates that valleys in the Jialing River's watershed were important routes for the movement of Neolithic populations from the catchments of the Yellow River to the Yangtze River. Here, we examine how fluvial geomorphological regime shifts may have also influenced the migration pathways and adaptive strategies of Neolithic people into the Sichuan Basin by using a combination of sedimentological and palynological analysis at Luojiaba, an archaeological site located on one of the eastern tributaries of the Jialing River. The results show that people settled on seasonally stable landforms, including the Zhonghe River floodplain at Luojiaba (5300–4800 cal. B.P.). They carried out fishing and hunting activities on the front edge of the floodplain close to the river channel and built dwelling features on the higher ground at the back edge of the floodplain, which was not affected by seasonal floods. We hypothesize that during the Holocene Climatic Optimum before 5500 cal. B.P., high water levels as well as severe surface erosion caused by a strong East Asian Summer Monsoon (EASM) blocked pathways into the upper reaches of the Jialing River watershed. Only after a series of cold, dry climate events driven by a decrease in EASM intensity ca. 5500–5000 cal. B.P. did water levels recede significantly. This allowed alluvial aggradation to occur, which created floodplains and terraces along the valley that may have opened a new route for the migration into the Sichuan Basin. Our results reveal the human–environment dynamics surrounding Luojiaba in the uplands of southwestern China and highlight the impact of coupled climatic‐geomorphic regime shifts on human settlement and subsistence strategies, across both space and time. [ABSTRACT FROM AUTHOR]

Neanderthals were widespread during the Middle Palaeolithic (MP) across Europe and Asia, including the Caucasus Mountains. Occupying the border between eastern Europe and West Asia, the Caucasus is important region regarding the Neanderthal occupation of Eurasia. On current radiometric estimates, the MP is represented in the Caucasus between about 260–210 ka and about 40 ka. Archaeological record indicates that several culture diverse MP hominin populations inhabited the Caucasus, but the region complex population history during this period remains poorly understood. In this paper, we identify for the first time the archaeological evidence indicating contacts between two culture diverse MP Neanderthal populations in the North Caucasus and discuss the nature of these contacts. Basing on the lithic assemblages that we excavated at Mezmaiskaya cave in the north-western Caucasus (Kuban River basin) and Saradj-Chuko grotto in the north-central Caucasus (Terek River basin), dating from MIS 5 to MIS 3, and comparative data from other MP sites in the Caucasus, we identify two large cultural regions that existed during the late MP in the North Caucasus. The distinctive toolkits and stone knapping technologies indicate that the MP assemblages from Mezmaiskaya cave and other sites in the west of North Caucasus represent a Caucasian variant of the Eastern Micoquian industry that was wide spread in central and eastern Europe, while the assemblages from Saradj-Chuko Grotto and other sites in the east of North Caucasus closely resemble the Zagros Mousterian industry that was wide spread in the Armenian Highlands, Lesser Caucasus and Zagros Mountains. The archaeological evidence implies that two culture diverse populations of Neanderthals settled the North Caucasus during the Late Pleistocene from two various source regions: from the Armenian Highlands and Lesser Caucasus along the Caspian Sea coast, and from Russian plain along the Sea of Azov coast. [ABSTRACT FROM AUTHOR]

Previous studies suggest that flood-rich and flood-poor periods are present in many flood peak discharge series around the globe. Understanding the occurrence of these periods and their driving mechanisms is important for reliably estimating future flood probabilities. We propose a method for detecting flood-rich and flood-poor periods in peak-over-threshold series based on scan-statistics and combine it with a flood typology in order to attribute the periods to their flood-generating mechanisms. The method is applied to 164 observed flood series in southern Germany from 1930 to 2018. The results reveal significant flood-rich periods of heavy-rainfall floods, especially in the Danube river basin in the most recent decades. These are consistent with trend analyses from the literature. Additionally, significant flood-poor periods of snowmelt-floods in the immediate past were detected, especially for low-elevation catchments in the alpine foreland and the uplands. The occurrence of flood-rich and flood-poor periods is interpreted in terms of increases in the frequency of heavy rainfall in the alpine foreland and decreases of both soil moisture and snow cover in the midlands. [ABSTRACT FROM AUTHOR]

Natural flood management (NFM) is a method for reducing flooding by using a catchment‐based approach to managing flood risk. Understanding and quantifying the impact of implementing NFM at the catchment scale remains ambiguous with a clear need for robust empirical evidence. A combination of fieldwork, laboratory analysis and modelling was applied to quantify the impacts of land use management changes on catchment flood hazard. Soil hydraulic conductivity was measured under varying land management regimes and used to parameterize a physically based spatially distributed hydrological model (SD‐TOPMODEL). A suite of stakeholder informed land management scenarios was modelled, permitting the quantification of the impact of NFM interventions on the timing and the intensity of the peak discharge at the catchment outlet. The findings support the implementation of NFM interventions as a means of reducing flood hazard within a rural upland catchment. Improved soil infiltration provided the greatest reduction in the intensity and delayed timing of the flood peak for a 10‐year occurrence storm event (7% reduction in peak runoff and 8% increase in lag time) with similar reductions observed for a 100‐year storm event. Catchment wide woodland planting reduced peak flow by 11% during the 100‐year event but was not effective during the 10‐year event. Riparian buffer strips provided consistent reductions in peak flow and in the timing of the peak across both storm events with no significant differences relating to vegetation age. Critically, we observed that the effect of implementing multiple NFM interventions was not additive and that efficiencies can be made in using this modelling approach to prioritize the most effective outcomes. [ABSTRACT FROM AUTHOR]

River networks transport dissolved organic carbon (DOC) from terrestrial uplands to the coastal ocean. The extent to which a reach or lake within a river network uptakes DOC depends on the stream order, the seasonal conditions, and the flow. At the watershed scale, it remains unclear whether DOC uptake is dominated by biological processes such as respiration, or abiotic processes like photomineralization. The partitioning of DOC uptake in lakes vs. rivers is also unclear. In this study, we present a new model that unifies year‐round controls on DOC cycling for an entire river network, including river–lake connectivity, to elucidate the importance of biotic vs. abiotic controls on DOC uptake. We present the Catchment UPtake and Sinks by Season, Order, and Flow for DOC (CUPS‐OF‐DOC) model, which quantifies terrestrial DOC loading, gross primary productivity, and uptake via microbes and photomineralization. The model is applied to the Connecticut River Watershed, and accounts for cascading reach‐ and lake‐scale DOC cycling across 98 scenarios spanning combinations of flows, seasons, and stream orders. We show that riverine DOC uptake is nearly constant with stream order, but the proportion of DOC uptake from photomineralization varies. Photomineralization dominates in rivers in most flow conditions and stream orders, especially in winter, accounting for at least half of whole‐watershed DOC uptake in February across all flows. Whole‐watershed summer DOC uptake occurs mostly via biomineralization in lakes, accounting for 80% of DOC uptake during the growing season, despite accounting for less than 6% of watershed open water surface area. [ABSTRACT FROM AUTHOR]

Many fields have identified an increasing need to use global satellite precipitation products for hydrological applications, especially in ungauged basins. In this study, we conduct a comprehensive evaluation of three Satellite-based Precipitation Products (SPPs): Integrated Multi–satellitE Retrievals for GPM (IMERG) Final run V6, Soil Moisture to Rain (SM2RAIN)-Advanced SCATterometer (ASCAT) V1.5, and Multi-Source Weighted-Ensemble Precipitation (MSWEP) V2.2 for a subbasin of the Mekong River Basin (MRB). The study area of the Srepok River basin (SRB) represents the Central Highland sub-climatic zone in Vietnam under the impacts of newly built reservoirs during 2001–2018. In this study, our evaluation was performed using the Rainfall Assessment Framework (RAF) with two separated parts: (1) an intercomparison of rainfall characteristics between rain gauges and SPPs; and (2) a hydrological comparison of simulated streamflow driven by SPPs and rain gauges. Several key findings are: (1) IMERGF-V6 shows the highest performance compared to other SPP products, followed by SM2RAIN-ASCAT V1.5 and MSWEP V2.2 over assessments in the RAF framework; (2) MSWEP V2.2 shows discrepancies during the dry and wet seasons, exhibiting very low correlation compared to rain gauges when the precipitation intensity is greater than 15 mm/day; (3) SM2RAIN–ASCAT V1.5 is ranked as the second best SPP, after IMERGF-V6, and shows good streamflow simulation, but overestimates the wet seasonal rainfall and underestimates the dry seasonal rainfall, especially when the precipitation intensity is greater than 20 mm/day, suggesting the need for a recalibration and validation of its algorithm; (4) SM2RAIN-ASCAT had the lowest bias score during the dry season, indicating the product's usefulness for trend analysis and drought detection; and (5) RAF shows good performance to evaluate the performance of SPPs under the impacts of reservoirs, indicating a good framework for use in other similar studies. The results of this study are the first to reveal the performance of MSWEP V2.2 and SM2RAIN-ASCAT V1.5. Additionally, this study proposes a new rainfall assessment framework for a Vietnam basin which could support future studies when selecting suitable products for input into hydrological model simulations in similar regions. [ABSTRACT FROM AUTHOR]

Andit tid watershed is part of Blue Nile basin located in the central highlands of Ethiopia. The lack of data and information at watershed level resulted in different conclusions from trend studies of river flow, sediment yield and crop productivity at a basin scale. There is an opportunity to improve water and land if it can be underpinned by a better scientific understanding of trends of flow, sediment yield and crop production at the basin level. This research is carried out using descriptive statistics, Mann-Kendall (MK) and Pettit's test to determine the potential trends of river flow, sediment yield and crop productivity using Andit tid watershed case. The result showed that there was high variability of interannual river flow with CV >30%. The Pettitt test showed a significant abrupt change in monthly (March, July, August, September and October) and seasonal (summer and winter) river flow. The Pettitt test result of sediment yield and crop production showed no change. MK test showed a significant (P < 0.05) decreasing trend in March, August, September and October river flow. The other MK values showed no significant trends for all parameters. Researchers should consider representative watershed-based information and data for the analysis and interpretation of large basins. [ABSTRACT FROM AUTHOR]

Due to the poorly managed water network of the Dschang municipality (West Cameroon), the peri-urban population of the Lefock watershed, frequently, consumes doubtful quality water from alternative supply points (WASPs) such as springs, wells, boreholes, and river waters. In this context, this study aimed to explore the influence of neighboring environmental conditions on the contamination of these resources. Thus, 22 WASPs and their immediate perimeter were characterized (within a 10 m radius), both from physiographic (nature of bedrock, type of WASPs, soil type, land use) and anthropogenic (presence of pit latrines, domestic wastewater, domestic breeding, agricultural activities, wild garbage dump, washing clothes on-site) points of view. In parallel, chemical (NO3−, NH4+, PO43−) and bacteriological (faecal coliforms, faecal streptococci, total coliforms, and E. coli) contamination parameters were analyzed and compared with the World Health Organization (WHO) standards. Multiple Factor Analysis (MFA) was performed, using water quality variables as input combined with environmental data as supplementary data. This approach first revealed that waters from WASPs were generally of very poor bacterial quality due to proximity to pit latrines, domestic wastewaters, and/or agricultural surfaces. Second, chemical contamination was greater where WASPs were neighboring to agricultural plots and/or domestic wastewaters. The MFA showed that the chemical degradation of WASPs mostly occurs at the watershed scale rather than very local scale, and was representative of diffuse and likely long-term pressures over the resource. In contrast, bacteriological contaminations were better governed by immediate contexts and appeared to result from the combination of anthropogenic and physiographic constraints. Regarding the influence of physiographic characteristics, the type of soil and the nature of the WASPs are the main influencing factors. The hydromorphic context accentuates the general vulnerability, while an increasing vulnerability related to the type of WASPs was observed: spring < well and borehole < river. These results indicate that structural poor water management, combined with a limited consideration of local environmental specificities threaten sustainability of this resource in semi-urbanized zones over heterogeneous aquifers and the water security of its population. This argues for a strong twofold education effort for managers and end-users of the resource. [ABSTRACT FROM AUTHOR]

As the frequency and magnitude of storm events increase with climate change, understanding how season and management influence flood peaks is essential. The influence of season and management of grasslands on flood peak timing and magnitude was modelled for Swindale and Calderdale, two catchments in northern England. Spatially‐Distributed TOPMODEL was used to investigate two scenarios across four storm events using empirically‐based soil and vegetation data. The first scenario applied seasonal changes in vegetative roughness, quantifying the effect on flood peaks at catchment scale. The second scenario modelled the influence of grassland management from historical high‐intensity grazing to a series of natural succession stages between grassland and woodland, and a conservation‐based management. Model outputs were analysed by flow type, measuring total, overland and base flow peaks at the catchment outlet. Seasonal changes to vegetation were found to increase overland flow peaks by up to +2.2% in winter and reduce them by −5.5% in summer compared to the annual average. Percentage changes in flood peak due to hillslope grassland management scenarios were more substantial; overland flow peaks were reduced by up to 41% in Calderdale where extensive woodland development was the most effective mitigation strategy, and up to 35% in Swindale, where a rank grassland dominated catchment was the most effective. Conservation‐based farming practices were also useful, reducing overland flow peak by up to 42% compared to the high intensity grazing scenario. Neither management nor seasonality changed the timing of runoff peaks by >45 min. Where overland flow dominates, especially in catchments with shallow soils, surface roughness was found to be more influential than soil permeability for flood mitigation. We recommend that seasonal changes to roughness are considered alongside the spatial distribution of Natural Flood Management in mosaiced upland catchments. [ABSTRACT FROM AUTHOR]

The morpho-tectonic characteristics of the study area were evaluated due to paleo-tectonic significance. The Upper Tons Basin is associated with the Ganga river system, originated over the fracture zones produced after the collision of Indian and Eurasian plates; hence, the study region has its tectonic importance with small-scale tectonic deformation. The relief, drainage and tectonic characteristics are analyzed by using digital elevation model and topographical maps, geomorphic indices, lineaments and transverse profiles. Result reveals that two-third areas are in declining from mature stage (HI < 0.50) or monadnock phase (HI < 0.40). The value of basin asymmetry factor is suggesting right-side tilting of the trunk stream due to the tributaries of the Tons river originating over the Bhander uplands being longer. Further, the comparison of the stream length gradient with normalized stream length gradient shows delineating tectonically anomalous regions, and the anomalous points are addressed in the longitudinal profiles. The scarps fronts of the plateau are more sinuous and highly eroded, while the straight Kaimur fronts indicate relatively sensitive fronts. The relative tectonic activity index helps to evaluate the potential tectonic activity of a drainage basin and drainage network developed over the tectonically pre-designed valley. [ABSTRACT FROM AUTHOR]

One popular Natural Flood Management (NFM) technique involves the construction of channel‐spanning woody dams in low‐order streams that maintain a clearance height above base flows. While extensive research has examined the geomorphic effects of natural wood accumulations, little has been documented of NFM woody dams, which are structurally distinct from natural accumulations and may produce different patterns of erosion and deposition. This consideration is crucial because changes in physical habitat characteristics have implications for flood management objectives as well as ecosystem structure and functioning. This study adopted a Before‐After Control‐Impact (BACI) design to assess the geomorphic effects of NFM woody dams in the upper River Cover catchment, United Kingdom. One baseline survey prior to and three monitoring surveys up to 2 years following dam construction were conducted. Structure‐from‐Motion (SfM) photogrammetry was employed to capture topographic change, supplemented by bathymetric surveys. Results highlight that where the dams remained secure in place, they promoted in‐stream habitat diversity by creating underflow pools. Sediment storage was observed only where the dams had clearance heights <0.3 m from the stream bed. Additionally, the dams commonly led to bank erosion, likely enhanced by inherent bank instability in the study catchment as observed along the control reaches. However, volumes of sediments eroded and deposited were not statistically different between the control and woody dam reaches. Longer monitoring is required to determine whether these effects on channel morphology and habitat diversity will persist, amplify, or diminish over time, and to better understand the longevity of NFM woody dams. [ABSTRACT FROM AUTHOR]

About 10% of Europe's surface area is prone to rapid flooding of rivers confined in valleys. The devastating potential of such floods is exacerbated by the deficits of existing gauging networks, including low station densities and recording frequencies, and lack of information beyond stage height. Here, we use seismic data of the July 2021 Ahrtal flood, Germany, to extract information to complement sparse hydrometric data, and to reconstruct the rapid evolution of this fatal event. We show that a seismic station can deliver essential flood metrics such as magnitude, propagation velocity and debris transport rate. These seismic products provide high resolution insight to the non‐linear flood behavior. We argue that an approach combining distributed low‐cost seismometers with existing seismic stations, can provide important real time data on future catastrophic floods and associated hazards in upland catchments, offering precious response time also in currently ungauged landscapes. Plain Language Summary: Rapidly evolving floods are a major hazard for 10% of European landscapes. They are hard to adequately detect and describe by the classic gauge station scheme, but seismic sensors provide a valuable alternative to this difficulty. A seismometer can sense a flood like the devastating one that hit the Ahr valley, Germany, in July 2021 up to 1.5 km away. The seismic footprint of the flood allows to provide information on flood magnitude, velocity and trajectory at sub‐minute resolution and at near real time. We show how this new approach can be utilized for future flood protection. Key Points: Seismic sensing of valley confined floods improves classic detection approachesNear‐real time information on flood magnitude, trajectory, and velocityGate keeper seismometer networks can improve flood risk management in Europe [ABSTRACT FROM AUTHOR]

Soil erosion accelerated by human activities is a critical challenge affecting soil health, agricultural productivity, food security and environmental sustainability in the highlands of Ethiopia. The aim of this study was to examine the dynamics of soil loss and sediment yield potential, and identify soil erosion hotspots using RUSLE with GIS in the Suha watershed, north western highlands of Ethiopia. Digital Elevation Model, LU/LC, rainfall, soil, and conservation practice were used as input data for RUSLE model. The estimated total annual soil loss for the entire watershed increased from 1.22 million tons in 1985 to 2.43 million tons in 2019, with average annual soil loss rates of 15.2 t ha−1 yr−1 and 31.4 t ha−1 yr−1 respectively. Total sediment yield also increased from 317.52 to 630.85 thousand tons over the past 35 years. In addition, the area of soil erosion hotspots changed from 15.2% (12,708 ha) to 32% (25,660 ha) during the same periods. Sub watershed 1, 2, 15, 17, 18, and 23 are severely degraded parts of the watershed. Expansion of agriculture and bare land as the expenses of other land use types over the past 35 years could be the major causes of extensive soil erosion risk in the watershed. Besides its temporal variability, soil loss and sediment export also showed variation between land use/cover classes. The estimated results of soil loss and sediment yield as well as soil erosion hotspots revealed that the soil erosion risk is progressively increasing during the study periods. Unless action is taken and the current condition is reversed, it will critically threat the livelihoods of the community in the watershed. Generally, the results underscore urgent demand for integrated and effective watershed management strategies. [ABSTRACT FROM AUTHOR]

Understanding effects of climate change on nitrogen fate and transport in the environment is critical to nutrient management. We used climate projections within a previously calibrated spatially referenced regression (SPARROW) model to predict effects of expected climate change over 1995 through 2025 on total nitrogen fluxes to Chesapeake Bay and in watershed streams. Assuming nitrogen inputs and other watershed conditions remain at 2012 levels, effects of increasing temperature, runoff, streamflow, and stream velocity expected between 1995 and 2025 will include an estimated net 6.5% decline in annual nitrogen delivery to the bay from its watershed. This predicted decline is attributable to declines in the delivery of nitrogen from upland nonpoint sources to streams due to predicted warmer temperatures. Such temperature‐driven declines in the delivery of nitrogen to streams more than offset predicted increased delivery to and within streams due to increased runoff and streamflow and may be attributable to increasing rates of denitrification or ammonia volatilization or to changes in plant phenology. Predicted climate‐driven declines in nitrogen flux are generally similar across the watershed but vary slightly among major nonpoint source sectors and tributary watersheds. Nitrogen contributions to the bay from point sources are not affected by temperature‐driven changes in delivery from uplands and are therefore predicted to increase slightly between 1995 and 2025. Research Impact Statement: Assuming nitrogen inputs and other watershed conditions remain constant, near‐term effects of climate change may include decreased delivery of nitrogen to Chesapeake Bay from its watershed. [ABSTRACT FROM AUTHOR]

The article presents predicted changes in soil water content in the Bystra river catchment (eastern Poland) for various scenarios of climate change and adaptation practices obtained on the basis of a SWAT model simulation for three regional climate models driven by the global climate model EC-EARTH for the years 2041–2050 and the RCP 4.5 and 8.5 RCP scenarios. Climate scenarios were put against five adaptation scenarios presenting changes in land use and protective measures compared against a zero scenario of BaU (Business as Usual) kept in the future climate. Adaptation scenarios 1–5 are modifications of Scenario 0 (S-0). The 0–5 scenarios' analysis was based on comparing soil water content and total runoff, sediment yield, actual evapotranspiration. The first adaptation scenario (AS-1) assumes an increase in afforestation on soils from the agricultural suitability complex of soil 6–8 (semi-dry, permanent dry, semi-wet). The second adaptation scenario (AS-2) assumes the creation of a forested buffer for the Bystra River and its tributaries. The third adaptation scenario (AS-3) shows one of the erosion prevention practices, the so-called filter strips. The fourth adaptation scenario (AS-4) assumes the reduction in plowing on arable land. The fifth adaptation scenario (AS-5) involves increasing soil organic carbon to 2%. Simulations revealed that each of the adaptation scenarios 1, 2, 3, 5 does not generally contribute to increasing the water content in soil on BARL (spring crops), CANP (rape), WWHT (winter crops), CRDY (other crops) on arable lands (which together account for over 50% of the catchment area). However, they can contribute to the reduction in sediment yield, total runoff and changes in actual evapotranspiration. The adaptation scenario 4 (AS-4) shows a slight increase in the soil water content on Bystra catchment in the 2041–2050 perspective. Scenario 4 indicated a slight increase in total runoff and a decrease in sediment yield, which in combination with slightly higher water content reflects the protective role of plant residue mulch, lowering the evaporation from the bare soil surface during warm seasons. The no-till adaptation practice had the highest effect in positively affecting water balance at the catchment scale among the adaptation scenarios considered. [ABSTRACT FROM AUTHOR]

The Bafoussam-Mamfe Region (BMR) belongs to the Western Cameroon Highland margin, an amalgam of transient landscape that evolved from the interactions between tectonics, lithology and climate forcings. This area is tectonically active and shows differential tectonic uplift, contrasting relief, variations in erosion rates, in river incision, and in channel gradient. In order to appraise the BMR tectono-geomorphic evolution, it is essential to understand relationships between internal and external processes and their geomorphic expression at a river basin scale. For this purpose, we use drainage texture (Dt), stream frequency (Fs), drainage density (Dd), asymmetry factor (AF), the transverse topographic symmetry factor (TTSF), the mean of mountain front sinuosity per unit (Smf), concavity factor (Cf), hypsometry integral (HI) and stream-length gradient index (SL-index) based on 30 m Digital Elevation Models (DEM) and field survey. The results reveal considerable variations in geology, relief, topography and geomorphic indices values differentiated into three geomorphic units; the Mamfe unit developed on the Mamfe Cretaceous basin, the Nguti and Bafoussam high plateau units build up on the Precambrian granito-gneissic basement overlaid by a volcanic cover. The stepped (longitudinal and normalized) river profiles and complex hypsometric curves show the lithostructural control of the hydrographic network. Dt (from ∼1.21 to ∼4.59), Fs (from ∼0.26 to ∼1.91), Dd (from ∼0.66 to ∼1.71) geomorphic indice values indicate a part of lithologic control on this morphology while the AF (from ∼1.16 to ∼24.91), TTSF (from ∼0.20 to ∼0.71), Smf (U2 = 1.11 and U3 = 1.19), Cf (from ∼−20.91 to ∼78.93), HI (from ∼0.12 to ∼0.52) and SL-index designate the active tectonics as the main factor that had controlled the morphology of this same area. Above results pinpoint the combined post-Pan-African to Recent tectonic features, lithologic heterogeneities and the differential erosion processes as main factors that have controlled the BMR landscape. These results highlight how the Central African surface and the West African passive margin evolved since Proterozoic time. [ABSTRACT FROM AUTHOR]

Significant hydropower projects have resulted in fragmentation of the rivers and alteration of flow regimes with consequent adverse effects on the river's ecosystems. To conserve aquatic ecosystems, the minimal desired river flow regime—environmental flows—is advised to maintain in the river system. While maintaining environmental flows, it is equally important to carry out the impact of environmental flows over the hydro-energy generation capacity of hydropower projects. In the present study, the energy generation reduction of provisioning environmental flows has been assessed for five major hydro electric projects on Rivers Bhagirathi and Alaknanda, the two significant head-streams of India's national river Ganga, located in the Himalayan uplands. The E-Flows assessment done by Tare et al., (2017) is used in the present study, which rationally integrates the ecological and geo-morphological needs of the river. Tare et al., (2017) recommended monthly E-Flows for the upper Ganga basin from ~ 23 to ~ 40% and ~ 29 to ~ 53% of natural flows for the wet and lean periods, respectively. They assessed E-Flows using flow data of the Bhagirathi and Alaknanda rivers for 1972–1982 and 1977–1987, respectively. The annual average reduction in potential energy production due to E-Flows provision in the Alaknanda-Bhagirathi basin is found in between 14.9 and 21.0% for these hydro electric projects. The estimated reduction in energy generation is higher in the lean flow period than in the wet period. This study shows that about 79 to 85% of capacity power generation is possible in the basin after provisioning E-Flows. [ABSTRACT FROM AUTHOR]

An increasing frequency of extreme atmospheric events is challenging our basic knowledge about the resilience mechanisms that mediate the response of small mountainous watersheds (SMW) to landslides, including production of water-derived ecosystem services (WES). We hypothesized that the demand for WES increases the connectivity between lowland and upland regions, and decreases the heterogeneity of SMW. Focusing on four watersheds in the Central Andes of Colombia and combining "site-specific knowledge", historic land cover maps (1970s and 1980s), and open, analysis-ready remotely sensed data (GLAD Landsat ARD; 1990–2000), we addressed three questions. Over roughly 120 years, the site-specific data revealed an increasing demand for diverse WES, as well as variation among the watersheds in the supply of WES. At watershed-scales, variation in the water balances—a surrogate for water-derived ES flows—exhibited complex relationships with forest cover. Fractional forest cover (pi) and forest aggregation (AIi) varied between the historic and current data sets, but in general showed non-linear relationships with elevation and slope. In the current data set (1990–2000), differences in the number of significant, linear models explaining variation in pi with time, suggest that slope may play a more important role than elevation in land cover change. We found ample evidence for a combined effect of slope and elevation on the two land cover metrics, which would be consistent with strategies directed to mitigate site-specific landslide-associated risks. Overall, our work shows strong feedbacks between lowland and upland areas, raising questions about the sustainable production of WES. [ABSTRACT FROM AUTHOR]

In the present study, we provide data on the first established, self-sustaining population of non-native brook trout (Salvelinus fontinalis Mitchill, 1814), family Salmonidae, in Bulgaria. The brook trout was detected in upland section of the Palakariya River (Iskar basin) at an altitude between 1350 and 1500 m a.s.l. Distribution, abundance and size structure of S. fontinalis were studied in the period 2019-2021. The coexistence of individuals of different sizes (from 4.1 cm to 24.6 cm); no restocking activities in the last 10 years and the suitable environmental habitat features support the contention of a self-reproducing population of S. fontinalis in the Palakariya River. [ABSTRACT FROM AUTHOR]

Flooding is an important process in natural fluvial floodplains. How the flood shapes aquatic community diversity in highland floodplains is still poorly understood. The aim of this study was to unravel the multi-faceted responses of benthic macroinvertebrate diversity to flooding and habitat environments in the Baihe River Basin from a taxonomic, phylogenetic, and functional perspective. We examined the alpha and beta diversity patterns of benthic macroinvertebrate communities in the mainstream, tributaries, and oxbow lakes during the normal water and flood periods. The results showed that the traditional alpha taxonomic diversity (TD) varied across habitats, despite minor changes after flood pulse. Alpha phylogenetic diversity (PD) decreased and alpha functional diversity (FD) markedly increased after flooding, with functional traits transiting toward risk avoidance. While all the three facets of beta diversity significantly responded to habitat differences, beta TD and PD shifted in response to flooding. Species turnover prominently increased in beta TD and PD after flood pulse, which contrasted with a weaker response of this process in FD. The explanatory power of significant environmental factors on both alpha and beta diversity was reduced by flooding. Compared with traditional TD, cooperating multi-faceted diversity could better depict the responses of benthic macroinvertebrate communities to flooding. The assessment and conservation of aquatic biodiversity in highland floodplains should take into account the three facets of alpha and beta diversity. • The benthic responded significantly to flood pulse in a highland floodplain. • TD varied across habitats, whereas PD and FD changed after flooding. • βsor and βsim respectively characterize habitat differences and flooding. • Functional traits shift to risk avoidance abilities after flooding. • Flooding weakens environmental effects on macroinvertebrate diversity. [ABSTRACT FROM AUTHOR]

Background: Persons with submicroscopic malaria infection are a major reservoir of gametocytes that sustain malaria transmission in sub-Saharan Africa. Despite recent decreases in the national malaria burden in Kenya due to vector control interventions, malaria transmission continues to be high in western regions of the country bordering Lake Victoria. The objective of this study was to advance knowledge of the topographical, demographic and behavioral risk factors associated with submicroscopic malaria infection in the Lake Victoria basin in Kisumu County. Methods: Cross-sectional community surveys for malaria infection were undertaken in three eco-epidemiologically distinct zones in Nyakach sub-County, Kisumu. Adjacent regions were topologically characterized as lakeshore, hillside and highland plateau. Surveys were conducted during the 2019 and 2020 wet and dry seasons. Finger prick blood smears and dry blood spots (DBS) on filter paper were collected from 1,777 healthy volunteers for microscopic inspection and real time-PCR (RT-PCR) diagnosis of Plasmodium infection. Persons who were PCR positive but blood smear negative were considered to harbor submicroscopic infections. Topographical, demographic and behavioral risk factors were correlated with community prevalence of submicroscopic infections. Results: Out of a total of 1,777 blood samples collected, 14.2% (253/1,777) were diagnosed as submicroscopic infections. Blood smear microscopy and RT-PCR, respectively, detected 3.7% (66/1,777) and 18% (319/1,777) infections. Blood smears results were exclusively positive for P. falciparum, whereas RT-PCR also detected P. malariae and P. ovale mono- and co-infections. Submicroscopic infection prevalence was associated with topographical variation (χ2 = 39.344, df = 2, p<0.0001). The highest prevalence was observed in the lakeshore zone (20.6%, n = 622) followed by the hillside (13.6%, n = 595) and highland plateau zones (7.9%, n = 560). Infection prevalence varied significantly according to season (χ2 = 17.374, df = 3, p<0.0001). The highest prevalence was observed in residents of the lakeshore zone in the 2019 dry season (29.9%, n = 167) and 2020 and 2019 rainy seasons (21.5%, n = 144 and 18.1%, n = 155, respectively). In both the rainy and dry seasons the likelihood of submicroscopic infection was higher in the lakeshore (AOR: 2.71, 95% CI = 1.85–3.95; p<0.0001) and hillside (AOR: 1.74, 95% CI = 1.17–2.61, p = 0.007) than in the highland plateau zones. Residence in the lakeshore zone (p<0.0001), male sex (p = 0.025), school age (p = 0.002), and living in mud houses (p = 0.044) increased the risk of submicroscopic malaria infection. Bed net use (p = 0.112) and occupation (p = 0.116) were not associated with submicroscopic infection prevalence. Conclusion: Topographic features of the local landscape and seasonality are major correlates of submicroscopic malaria infection in the Lake Victoria area of western Kenya. Diagnostic tests more sensitive than blood smear microscopy will allow for monitoring and targeting geographic sites where additional vector interventions are needed to reduce malaria transmission. [ABSTRACT FROM AUTHOR]

Soil erosion and the subsequent sedimentation are the major problem in Ethiopia. We assessed the impact of rainfall-induced soil erosion and prioritize the sub-watersheds using RUSLE and SYI models. We procured mean annual precipitation, Abay Basin soil map, Digital Elevation Model (DEM) and LANDSAT 8 OLI/TIRS, 2017 datasets. Results show that annual estimated soil loss was ≤270 and ≤120 t ha−1 yr−1 whereas, mean rates were 37.72 and 23.92 t ha−1 yr−1 for RUSLE and SYI models respectively. Both the models have identified ∼25% area of sub-watersheds (SW19 to SW23) has similar average soil loss (>20 t ha−1 yr−1) at higher elevations. Interestingly, similar erosion severity, priority level and ranks were observed through RUSLE and SYI. Findings indicate a strong relationship between erosion rate and topography. The severe erosion prone area requires immediate action for conservation treatment proposed in study. [ABSTRACT FROM AUTHOR]

This study evaluates the performance of 43 Coupled Model Intercomparison Project phase 6 (CMIP6) models in reproducing annual cycle, climatology, and trend of observed precipitation over East Africa during 1950–2014. The results show that the CMIP6 models display good performance in simulating the annual cycle (i.e., bimodal pattern) of East African precipitation; however, most models and the multimodel ensemble mean (ENSEM) underestimate the March to May (MAM) precipitation while overestimating the October to December (OND) precipitation. Spatially, most models seem to perform relatively better in simulating OND precipitation compared to MAM season, despite wet (dry) biases over most parts of East Africa with the wettest (driest) biases over the Lake Victoria basin (southeastern Tanzania) during OND (MAM). The metrics have shown that nine models (i.e., MPI‐ESM1‐2‐HR, AWI‐CM‐1‐MR, MPI‐ESM1‐2‐LR, IPSL‐CM6A‐LR, CAS‐ESM2‐0, BCC‐CSM2‐MR, NorESM2‐LM, CESM2‐WACCM, and CMCC‐CM2‐SR5) outperform the other individual models during both OND and MAM. Compared with individual models, the ENSEM better agrees with the observation. Besides, the ENSEM and most models can reproduce the increasing trend in OND precipitation as observed over East Africa. However, for the secular change of MAM precipitation, given that half of the models show increasing trends, the ENSEM simulation produces an inconsistent trend with the observation. The ensemble of the above nine models with better performance projects an increase of precipitation averaged over East Africa in both MAM and OND by the end of the 21st century, with larger changes under SSP5‐8.5 than under SSP2‐4.5. Spatially, the largest percentage increase in MAM precipitation is projected to occur in central Tanzania and northwestern Kenya, while southeastern Tanzania shows the greatest percentage decrease. The projected percentage increases in OND precipitation are larger in the northeastern highlands of Tanzania and northwest Kenya. [ABSTRACT FROM AUTHOR]

In Vietnam, drought has been occurring persistently and in very complicated patterns, with a great impact on the water, energy, and food security nexus and regional development sustainability. The uncertainty surrounding annual water resources in combination with the low reliability of interbasin water transfer (IBWT) operations is the key driver of water deficits in several affected regions. This study aims to assess the impacts of four big IBWT projects in the Central Highlands of Vietnam, based on a proposed matrix of five evaluation criteria to quantify related impacts and to draw out lessons learned for future development of IBWT. The proposed criteria matrix was formulated on the basis of intensive reviews of IBWT assessments worldwide and relevant Vietnamese laws in force. The impacts were analysed and quantified mainly based on assessment of their operational database and water balance simulations for donor and recipient river basins in current and future states. The results show that the studied IBWT projects did not fully satisfy the proposed criteria set, all project did not meet the criteria of benefit sharing and information transparency; noticeably the Don Duong project fulfilled only one from five. Four lessons were determined for proper planning in river basins, flexibility in system design for unknown future, inadequate environmental impact assessment and delay in enactment of policies for IBWT project management. The results provide sound knowledge to revise the existing projects in the Central Highlands and procedures for impact assessment and approval of new IBWT systems. [ABSTRACT FROM AUTHOR]

From the earliest archaeological investigations along Central Asia's Tien Shan range, researchers have noted the diversity of highland communities and their participation in complex subsistence, exchange, and political systems. However, landscape archaeological approaches that might address socio-economic integrations have been limited by discontinuous, sometimes skewed datasets. Here, we present the results of UAV-based survey at Kok-Sai, an upland alluvial slope in the Kochkor Valley of north-central Kyrgyzstan, in which we identified more than 900 archaeological features in a 380 ha study area. Burials comprise roughly half of the identified features; stone structures, water catchments, irrigation channels, and terraces make up the other half. In an iterative interpretive process, we examine this busy landscape against high-resolution topographic and hydrological models, identifying repeated investment in the local physical and cultural infrastructure. Beyond the creation of a denser archaeological map for the area, the details of long-term, local landscape creation afforded by this study intersect with ongoing discussions of the organizational strategies and scales of highland agro-pastoralism. [ABSTRACT FROM AUTHOR]

The Kachchh province of India has witnessed several major earthquakes in the past 100 years. These earthquakes have reactivated major faults of the region and modified the landscape. Morphometric analysis of the Wagad Highland was carried out to assess the vulnerability of regional fracture patterns for neotectonic activities. The analysis of regional fractures (using hypsometric curves and rose diagrams) of the first order drainage brought out the presence of three major orientations, i.e., N005°, N025° and N075°. Five quantitative parameters, viz., mountain front sinuosity (Smf), asymmetry factor (AF), hypsometric integral (HI), the ratio of valley floor width to valley height (Vf), and sinuosity parameter (Sp) were combined to a common parameter, the index for relative active tectonics (IRAT), having four classes (very high, high, moderate and low). The intensity of the neotectonic activity decreases from Class 1 to Class 4. About 62% (~151 km2) of the total area (~244 km2) is under Class 1 and Class 2, out of which ~50% (~122 km2) is in the western part of the study area. Based on these IRAT classes, a major NE–SW lineament, passing through the center of the study area, was identified to be neotectonically more active. Research Highlights: Drainage basin morphometry of the Wagad Highlands (Rapar), India was analysed. Index for relative active tectonics (IRAT) supports very high neotectonic activity. IRAT map provides demarcation of neotectonically active zones. Seismicity in the Kachchh region is related to high strain along regional faults. [ABSTRACT FROM AUTHOR]

Concentration–discharge (C‐Q) relationships are an effective tool for identifying watershed biogeochemical source and transport dynamics over short and long timescales. We examined stormflow C‐Q, hysteresis, and flushing patterns of total suspended sediment (TSS) and soluble reactive phosphorus (SRP) in two stream reaches of a severely impaired agricultural watershed in northeastern Wisconsin, USA. The upper watershed reach—draining a relatively flat, row crop‐dominated contributing area—showed predominantly anti‐clockwise TSS hysteresis during storms, suggesting that particulate materials were mobilized more from distal upland sources than near‐ and in‐channel areas. In contrast, the incised lower watershed reach produced strong TSS flushing responses on the rising limb of storm hydrographs and clockwise hysteresis, signalling rapid mobilization of near‐ and in‐channel materials with increasing event flows. C‐Q relationships for SRP showed complex patterns in both the upper and lower reaches, demonstrating largely non‐linear chemodynamic C‐Q behaviour during events. As with TSS, anti‐clockwise SRP hysteresis in the upper reach suggested a delay in the hydrologic connectivity between SRP sources and the stream, with highly variable SRP concentrations during some events. A broad range of clockwise, anti‐clockwise, and complex SRP hysteresis patterns occurred in the lower watershed, possibly influenced by in‐channel legacy P stores and connection to tile drainage networks in the lower watershed area. Total suspended sediment and SRP responses were also strongly related to precipitation event characteristics including antecedent precipitation, recovery period, and precipitation intensity, highlighting the complexity of stormflow sediment and phosphorus responses in this severely impaired agricultural stream. [ABSTRACT FROM AUTHOR]

Upland river systems in the UK are predicted to be prone to the effects of increased flood magnitudes and frequency, driven by climate change. It is clear from recent events that some headwater catchments can be very sensitive to large floods, activating the full sediment system, with implications for flood risk management further down the catchment. We provide a 15‐year record of detailed morphological change on a 500‐m reach of upland gravel‐bed river, focusing upon the geomorphic response to an extreme event in 2007, and the recovery in the decade following. Through novel application of two‐dimensional (2D) hydrodynamic modelling we evaluate the different energy states of pre‐ and post‐flood morphologies of the river reach, exploring how energy state adjusts with recovery following the event. Following the 2007 flood, morphological adjustments resulted in changes to the shear stress population over the reach, resulting in higher shear stresses. Although the proportion of shear stresses in excess of those experienced using the pre‐flood digital elevation model (DEM) varied over the recovery period, they remained substantially in excess of those experienced pre‐2007, suggesting that there is still potential for enhanced bedload transport and morphological adjustment within the reach. Although volumetric change calculated from DEM differencing does indicate a reduction in erosion and deposition volumes in the decade following the flood, we argue that the system still has not fully recovered to the pre‐flood state. We further argue that Thinhope Burn, and other similarly impacted catchments in upland environments, may not recover under the wet climatic phase currently being experienced. Hence systems like Thinhope Burn will continue to deliver large volumes of sediment further down river catchments, providing new challenges for flood risk management into the future. [ABSTRACT FROM AUTHOR]

Tropical rivers such as the Rio Negro constitute a major portion of the global aquatic flux of dissolved organic carbon (DOC) entering the ocean, but the exact amount, source contributions and fate of terrestrial DOC remain unknown. We investigated the role of valley and upland whitesand ecosystems (WSEs) and terra firme plateaus in forming blackwater tributaries in the Rio Negro basin to develop novel constraints for the terrestrial export of carbon. 5709 molecular markers from ground- and surface waters of two contrasting valley and upland sites feeding Rio Negro tributaries were identified by ultrahigh resolution mass spectrometry (FT-MS), analyzed by multivariate statistics and compared to known Rio Negro markers. In a Principal Coordinates Analysis, valley and upland DOC molecular composition differed by 78% from plateau DOC, which was characterized by reworked, aliphatic and unsaturated N- and S-containing molecules, while valley and upland DOC contained mainly condensed aromatics, aromatics and oxidized unsaturated structures. Valley and upland samples differed by 10% in molecular DOC composition and by their isotopic content (14C of SPE-DOC, 18O and 2H of water) which indicated differences in hydrology and C turnover. Against expectation, markers of widespread whitesand valleys did not emerge as a major source of Rio Negro markers, but specific upland markers did. Pubchem suggested chromene and benzofuran structures as promising candidates for further study. Our findings indicate that the export of molecular markers diverges from expected transport-limited DOC behavior, and thereby opens new avenues for source annotation beyond DOC quantity. Terrestrial DOC from upland whitesand areas is a major source of specific blackwater molecules missing in the regional ecosystem C balance, whereas C export from the whitesand valleys and especially from terra firme plateaus represents mainly recycled and transformed carbon not directly affecting the ecosystem C balance and possibly, the watersheds downstream molecular signature. Our study highlights the potential of high-resolution techniques to constrain carbon balances of ecosystems and landscapes by novel molecular markers. A comparison with other terrestrial DOM datasets indicated molecular similarities with temperate acidic soils and tropical rivers that warrant further analysis of common DOM markers. Implications, limitations, and future challenges are discussed in the light of potential applications of diagnostic molecular links for DOC source annotation and estimation of terrestrial DOM export in the land-to-ocean continuum. [ABSTRACT FROM AUTHOR]

Despite claims about high avian biodiversity in the Indian River Lagoon system, previous efforts to inventory the birds have been limited in geographic extent or in habitat. Compilation of a list of birds could rely on many resources, but ones of widespread availability, greatest historical record. and highest density of sites are two citizen-science projects: the gbristmas Bird Count (CBC) and eBird. Lists of species were harvested from 17 CBC sites ("circles") back to 1910 and from 432 eBird sites ("hotspots-) since 2002 within the boundaries of the Indian River Lagoon National Estuary Program (IRLNEP). In addition to lagoon waters, the boundaries include barrier islands, wetlands, and uplands of the historical drainage. A total of 437 species of bird in 71 families were recorded at the CBC and eBird sites, but 6 species were eliminated because of low counts, lack of independent listing for the region or state in reliable sources, or likelihood of misidentifications. Addition of 12 species from Alan G. Cruickshank's records for Brevard County brought the total avifauna of the IRLNEP territory to 443 species, with retention of all 71 families. The inventory includes accidental and two extinct species and both established and unestablished exotic species. [ABSTRACT FROM AUTHOR]

The drought impacts in the Dakbla watershed were assessed based on a combination of hydrological modeling and drought indices. Three drought indices, the Standardized Precipitation Index (SPI), Standardized Soil Moisture Index (SSI), and Streamflow Drought Index (SDI) were utilized to evaluate the drought features of meteo-hydrology and agriculture. The results indicated that these indices are well adapted to the local conditions, especially the 12-month time scale. Evaluations of drought features on the watershed scale could provide more specific information regarding drought risk than regional-scale/district-level assessments, because a watershed is a hydrologically fundamental unit to consider water resources management. Additionally, evaluations of drought impacts using the SSI showed longer and higher trends than those using the SPI and SDI in terms of drought duration and frequency. Considering the spatial distribution of drought frequency, the areas predominated by agricultural land in the target watershed had higher drought risk. Thus, assessment of agricultural droughts along with meteo-hydrological droughts is extremely important to support realistic local drought management strategies by considering water availability, water balance, and soil characteristics, especially in specific agricultural areas. [ABSTRACT FROM AUTHOR]

The paper presents a preliminary report on the systematic surface exploration conducted in the Middle Ong basin with particular focus on the northern tributaries, viz. the Uttali, Ghensali and Mongragod stream in the southern Bargarh Upland of Western Odisha. The investigations have resulted in the discovery of 43 new prehistoric sites in the area with predominance of microlithic components. These sites are observed in different geomorphological contexts, such as, in the cliff surface of riverbanks, hillslope, foothills and rocky outcrops. Abundant availability of raw materials, mainly chert of different colors and vein quartz in the area seem to have attracted the prehistoric communities for intensive settlements in the area. while sporadic acheulian artifacts have been found scattered here and there, most of the documented sites are dominated by microlithic components, some of which have also been associated with used/unused red ochre minerals, suggesting advanced cognitive abilities and symbolic behavior of the microlith using communities in the area of investigation. [ABSTRACT FROM AUTHOR]