Floodplain Areas Research Articles

Fish Distribution in Lacustrine and Riverine Biotopes of Bratsk Reservoir Based on the Results of Hydroacoustic Surveys

Abstract Fish distribution in different areas of Bratsk Reservoir has been studied using hydroacoustic equipment. The average abundance of fish decreases (r = –0.70; p < 0.05; R 2 = 0.49) from the near-dam reach (214 ± 34 ind./ha) to the water area in the upper reaches of the reservoir (113 ± 43 ind./ha). A similar relationship is observed in the dynamics of the abundance of early juveniles and the immature fish population. However, such relationship has not been found in fish with a size of more than >100 mm, which with a low abundance are relatively evenly distributed along the longitudinal axis of the reservoir (10.5 ± 6.6 ind./ha). The common perch (Perca fluviatilis Linnaeus, 1758) is the most abundant species in the reservoir, its highest concentrations are recorded in the lower lacustrine part of the reservoir (139 ± 22 ind./ha). Less abundant cyprinids (Cyprinidae) (41 ± 15 ind./ha) and whitefishes (Salmonidae, Coregoninae) (12 ± 4 ind./ha) are more evenly distributed along the longitudinal axis of the reservoir. Temperature stratification of the water column is an important factor in the ecological differentiation of the fish population in the reservoir. The major part of the ichthyomass consisting of relatively warm-water fish species from the families Percidae and Cyprinidae (common roach (Rutilus rutilus (Linnaeus, 1758) and common bream (Abramis brama (Linnaeus, 1758)) is concentrated in the warming up epilimnion. The fish population in the cold hypolimnion consists of single individuals of the Baikal omul (Coregonus autumnalis (Georgi, 1775)) and peled (C. peled (Gmelin, 1789)). Transverse distribution of fish depends on the presence of a runoff flow. At relatively high flow rates, fish begin to avoid the midstream part in the studied sites of the reservoir and concentrate in the floodplain areas (R 2 = 0.54; p < 0.0001).

Evaluating the Economic Efficiency of Crop Production in the Floodplain During the Dry Season in Chulkiri District, Kampong Chhnang Province

Purpose of the study: This study aims to assess the status of crop production and evaluate the costs, benefits, opportunities, and challenges along Tonle Sap Lake during the dry season. Methodology: Data were collected from 47 farmers, 10 vendors, and four local authorities through random interviews followed by questionnaires. The cost-benefit ratio, net present value (NPV), and sensitivity analyses were conducted, assuming a 9% cost overrun and a 5% yield decrease for analysis data. Main Findings: The study found, that farmers employ crop rotation and expertise from nearby farmers to grow beans, corn, sweet chilli, and melon from December to August. Floodplain crop production is moderately profitable, despite a 10% increase in total costs, with labor, irrigation, fertilizer, weeding, and pesticides being the high expenses. Challenges such as labor scarcity, financial literacy deficits, pest management issues, falling crop values, climate variability, and insufficient seed storage further complicate floodplain agriculture. Novelty/Originality of this study: This research explores floodplain farming's financial efficiency, and sustainability, utilizing cost-benefit analysis, sensitivity analysis, and qualitative evaluations to address Cambodia's unique agricultural challenges in the floodplain area.

River stabilization reshaped human-nature interactions in the Lower Yellow River Floodplain

Floodplains are crucial agricultural and populated areas worldwide. Rivers typically shape human activities within floodplains through water supply and flood risk, forming unique human-nature interaction patterns. Given that river systems have undergone significant transformations globally, understanding the response of these interactions to hydrological changes is elementary. Here, using the Lower Yellow River Floodplain (LYRF) as a case, where continuous levees distinctly outline the river-influenced floodplain from a homogenous cultivated plain and the river's hydrology has undergone dramatic alterations since the 1990s, we analyzed how the human-nature interactions respond to river hydrological changes. This study found that the flood-prone nature of the Lower Yellow River has weakened from 1986 to 2021 as shown by decreased surface water extent and inundated extent of cropland. The intensity of agriculture inside the LYRF has been lower but experienced faster development than outside, minimizing the disparity between them. Meanwhile, human activities in the floodplain have moved closer to the river. These changes in human-nature interactions in the LYRF can be explained by the river stabilization caused by upstream regulation, underscoring the significance of integrated river governance in managing human-nature system in floodplain areas.

MAPPING AND GEOSPATIAL DISTRIBUTION OF AÇAÍ TREES (EUTERPE OLERACEA MART) IN THE TOCANTINA-PA AMAZON

The article aims to map and analyze açaí management and planting systems in floodplain and terra firma areas in the Tocantina Amazon, specifically in the municipality of Mocajuba, Pará. To achieve this work, remote sensing and geoprocessing techniques were used, where we sought characterize the spatial and temporal distribution of açaí groves and evaluate changes in the landscape over the years. The application of the spectral indices NDVI (Normalized Difference Vegetation Index), NDWI (Normalized Difference Water Index) and NDBI (Normalized Difference Construction Index) proved to be fundamental to identify areas with greater plant biomass, humidity levels and urban expansion, respectively. The results point to the importance of sustainable management practices to guarantee productivity and environmental preservation. It is concluded that the analysis of spectral indices proved to be effective in detecting variations in vegetation cover and water availability, providing crucial information for the planning and management of plantations in the region.

Isotopic labeling of nanoparticles for the evaluation of their environmental fate in mesocosm experiments

Mesocosm systems simulating floodplain areas are essential for the understanding of the environmental fate and effects of engineered nanoparticles (ENPs). In such mesocosm studies, the quantification of different types of nanoparticles coexisting in natural systems and containing the same element is often challenging. Such coexistence is expected e.g., for ENPs simultaneously released into the environmental systems. Despite the relevance of the coexistence, little is known about combined behavior and effects of ENPs in the environment. In this study, we developed a method for the quantification and differentiation of silver nanoparticles enriched by 109Ag isotope (109Ag-NPs) and sulfidized silver nanoparticles with natural isotopic distribution (S-Ag-NPs) in water, soil, and sediment and applied it to evaluate the environmental fate of these nanoparticles introduced simultaneously together with gold (Au-NPs) and titanium dioxide (TiO2-NPs) nanoparticles into mesocosms simulating an aquatic-terrestrial transition zone. High nanoparticle recoveries determined in water, sand, and soil spiked with nanoparticle mixtures indicate that the application of isotopically enriched ENPs will allow their differentiation from other nanoparticles containing the same element in environmental compartments even at the concentrations in the range of natural background. The co-accumulation of 109Ag-NPs, S-Ag-NPs, and Au-NPs in the top layer of sediment and soil and in biofilms observed in mesocosm studies suggests that these compartments can act as effective sinks for these ENPs. We suggest that the hetero-aggregation between different co-occurring ENPs and their high affinity to biota are major mechanisms controlling their fate in the aquatic-terrestrial transition zone. A high co-enrichment of 109Ag-NPs, S-Ag-NPs, Au-NPs, and TiO2-NPs in/on algae, biofilms, leaves, and amphipods suggests an enhanced risk of biomagnification. The findings of this study will contribute to a better understanding of the fate of ENPs and their combined effects in environmental compartments, where the simultaneous presence of diverse nanoparticles is expected.

Hydrological drought and floodplain disconnectivity: quantifying flow thresholds in a large coastal plain river

ABSTRACT Hydrological drought and river disconnectivity worsen from dams and human activities. This research investigates how dam constructions exacerbate hydrological drought and river disconnectivity in Apalachicola River system. Data from two hydrological stations (1928-2022), a hydrographic survey, high-resolution LiDAR, and a triangular irregular network (TIN) were used to identify three connectivity flow (141.5 m3/s, 169.8 m3/s, and 226.4 m3/s) categories, each impacting floodplain differently. A relative elevation model (REM) was also developed for floodplain connectivity assessment. Findings show a significant increase in the frequency, duration, and magnitude of connectivity low flow events from pre-dam to post-dam periods, especially at the 169.8 m³/s connectivity flow threshold. A 20th percentile variable threshold shows increasing hydrological drought. Drought increases have led to decreased connectivity between tributaries and the main river system, and an increase in the moderately disconnected floodplain area from 37.1% to 46.0%. Adaptive management strategies are needed to address drought-induced floodplain disconnectivity

A Comparative Evaluation of Embodied Environmental Impacts of Channel Stabilisation Using Concrete Lining and Alternative Pozzolanic Materials

Channel stabilisation with the lining of bed/ banks using cement-concrete (with/ without steel reinforcement as per the size, depth, and capacity), geomembrane, polymers, canvas, ramped earth, vegetation, gravel/ stone pitching, and brick blast is a common practice worldwide to save the adjacent flood plain areas from bank overflowing, seepage, water logging/ salinity, loss of water in irrigation channels, maintaining required water levels and strengthening of channels to be used as transportation means. A trapezoidal channel of cross-section 165 m2 and a lined perimeter of 42m was proposed to accommodate a super flood of 360 m3/sec discharge for a catchment area of 1446 km2 and 118 km length, using a projected heavy flood event of 6 cm precipitation in 8 hours for Swale River to ascertain the material calculation and its environmental impact. This concrete lining would likely produce an equivalent global warming potential/ embodied carbon dioxide (CO2) of 284 million kgCO2eq (kilogram CO2 equivalent) with the projected use of around 271 million kg of cement concrete and 78 million kg of steel. The enormous amount of embodied CO2 emissions from this projected lining project suggested using natural means of flood/ channel protection if feasible, or alternative supplementary cementitious materials with fibres should be used to minimise the environmental impacts.

Enormous headward and gully erosion in a floodplain area reclaimed for open-cast lignite mining during the July 2021 flood in the Inde River valley (Western Germany)

BackgroundThe July flood 2021 at the mountain front of the Eifel-Ardennes Mountains and their foreland resulted in the flooding of the lignite mining area of Inden in Germany. The mining activities resulted in large-scale anthropogenic changes to the relief and fluvial system, leading to a landscape that is no longer adjusted to the recent process-response system. This paper concentrates on the Inde River, where lignite mining led to the relocation of a 5-km-long river section. The flood event resulted in the temporary avulsion of the Inde River into the former channel and, ultimately, in the flooding of the open-cast lignite mine Inden.ResultsThe flooding of the open-cast lignite mine Inden led to headwall erosion and enormous sediment mobilisation, mobilising more than half a million cubic metres of sediment within a few hours, forming a 700-m-long deeply incised channel cut. Thereby, the underlying bedrock, near-subsurface man-made structures, and former river channels influence the erosional processes to different degrees. Surface erosion is likely to be the decisive process, and subsurface erosion is likely to play a secondary role. In both cases, former channels and mill ditches were likely impacting the course of erosional processes.ConclusionsDuring high flood events open-cast mining sites in floodplains are endangered by enormous erosion and sediment transport within a short period of time (several hours). Understanding such complex erosion and depositional processes in open-cast mining areas could provide a blueprint for geomorphological processes and hazards in these anthropogenically shaped fluvial landscapes. Further, information on historic impact in the area is crucial to estimate potential risks.

Love thy neighbour: Feral buffalos show greater space use, resource overlap and encounters during the wet season in the Northern Territory.

Managing feral water buffalo in the Northern Territory is a formidable challenge. As an introduced species, buffalo are associated with a myriad of biosecurity, economic, cultural and environmental issues ranging from overgrazing, decreased water quality, disease vectors to the destruction of cultural assets. Nevertheless, the buffalo are also a harvestable resource that can support economic development of the region. To mitigate some of the biosecurity, economic, cultural and environmental risks they pose and manage buffalo effectively, we need a detailed understanding of their spatial and behavioural ecology. However, several factors make understanding how best to manage the dense populations of wild individuals challenging as buffalo inhabit remote areas with limited infrastructure and accessibility and their large size and often aggressive nature can make them difficult to observe in otherwise inaccessible areas. GPS tracking allows for high-frequency data collection and surveillance of individual buffalo. Here, we investigated how the different seasonal periods of a Northern Territory floodplain area shaped patterns of habitat use for 17 buffalo tracked over 16 months. We found in the dry season, buffalo space use is restricted, and the size of home ranges are significantly smaller than in the wet season. During the wet season, buffalo expand their home range area as well as their social encounter area with other buffalo. These differences in their space use and social patterns suggest that increased disease surveillance may be needed for the wet season when buffalo are more likely to share space and interact. During the dry season, however, buffalo movement is more predictable and restricted, suggesting greater optimisation opportunities for buffalo management. Results from these models can be used by land holders, Traditional Owners and wildlife managers to make evidence-based decisions to improve buffalo management with respect to disease risk, sustainable harvest and damage to environmental and cultural assets.

Impacts of fire and flooding on sediment carbon storage in a large, forested floodplain

Summary Natural disturbances influence wetland carbon cycling, and fire is a key driver of terrestrial carbon stocks. However, the influence of fire on wetland carbon cycling remains poorly understood. Here, we investigated how prescribed fire and wildfire impact soil carbon storage in a forested floodplain of south-eastern Australia. We sampled four areas within Murray Valley National Park, the world’s largest river red gum (Eucalyptus camaldulensis) stand, and compared soil carbon (C), nitrogen (N) and C:N ratios between control (unburnt in the 50 years prior to sampling), prescribed burn and wildfire-impacted floodplain areas. Mean soil C and N concentrations were 4.7% ± 0.32% and 0.36% ± 0.02%, respectively, and mean C:N ratios were 14.23 ± 0.33. Carbon concentrations and C:N were highest in control areas of the floodplain, while N concentrations were highest at wildfire-impacted areas. However, flood frequency was a stronger driver of soil C than fire disturbance. Soils at more frequently flooded areas had higher C concentrations compared to less frequently flooded areas, suggesting that resilience to C loss through fire could be enhanced through hydrological restoration. We believe this warrants further research as a potential nature-based climate measure. Mean C density data indicate soil C stocks of 9.4 Tg across Barmah-Millewa Forest, highlighting the significant carbon storage value of this ecosystem.

Rhizobacteria Isolated from Amazonian Soils Reduce the Effects of Water Stress on the Growth of Açaí (Euterpe oleracea Mart.) Palm Seedlings.

Euterpe oleracea Mart., also known for its fruit açaí, is a palm native to the Amazon region. The state of Pará, Brazil, accounts for over 90% of açaí production. Demand for the fruit in national and international markets is increasing; however, climate change and diseases such as anthracnose, caused by the fungus Colletotrichum sp., lead to decreased production. To meet demand, measures such as expanding cultivation in upland areas are often adopted, requiring substantial economic investments, particularly in irrigation. Therefore, the aim of this study was to evaluate the potential of açaí rhizobacteria in promoting plant growth (PGPR). Rhizospheric soil samples from floodplain and upland açaí plantations were collected during rainy and dry seasons. Bacterial strains were isolated using the serial dilution method, and subsequent assays evaluated their ability to promote plant growth. Soil analyses indicated that the sampling period influenced the physicochemical properties of both areas, with increases observed during winter for most soil components like organic matter and C/N ratio. A total of 177 bacterial strains were isolated from rhizospheres of açaí trees cultivated in floodplain and upland areas across dry and rainy seasons. Among these strains, 24% produced IAA, 18% synthesized ACC deaminase, 11% mineralized organic phosphate, and 9% solubilized inorganic phosphate, among other characteristics. Interestingly, 88% inhibited the growth of phytopathogenic fungi of the genera Curvularia and Colletotrichum. Analysis under simulated water stress using Polyethylene Glycol 6000 revealed that 23% of the strains exhibited tolerance. Two strains were identified as Bacillus proteolyticus (PP218346) and Priestia aryabhattai (PP218347). Inoculation with these strains increased the speed and percentage of açaí seed germination. When inoculated in consortium, 85% of seeds germinated under severe stress, compared to only 10% in the control treatment. Therefore, these bacteria show potential for use as biofertilizers, enhancing the initial development of açaí plants and contributing to sustainable agricultural practices.

Dioxin-like and estrogenic activity screening in fractionated sediments from a German catchment after the 2021 extreme flood

BackgroundThe flood in July 2021 is considered one of the largest flood disasters in Western Europe in decades, with massive socio-economic consequences. The potential emission and remobilization of anthropogenic pollutants can lead to additional environmental consequences, which need to be addressed in long-term mitigation strategies. The Inde River and its tributary, the Vichtbach River, form a catchment located at the transition from the low mountain ranges of the Eifel to the lowlands of the Lower Rhine Embayment in Germany. The area has been an industrial and mining hotspot for centuries, making it a high-risk area for flood sediment pollution. The present study provides an ecotoxicological screening of flood sediments of the Vicht–Inde catchment to gain an impression of the degree of contamination by organic pollutants by means of in vitro effect-based method. Sediment samples were collected within days after the flood and fractionated prior to biotesting, and supportive instrumental geochemical analysis was performed.ResultsFlood sediments did not reveal estrogenic potential, which was included in the testing strategy as a relevant endpoint for industrial chemicals and untreated wastewater. In contrast, moderate-to-high dioxin-like activity was observed in 70% of the sediment samples with a peak dioxin-like potential at the restored section of the Inde. Overall, four hotspot samples were identified as at risk, which aligned mostly with the high concentration of organic pollutants including PAHs and PCBs. The fractionation allowed the identification of PAHs and their derivates as the most likely toxicity drivers for dioxin-like activity in the sediments of the Vicht–Inde catchment.ConclusionThe results provide first information on the prioritization of hotspot locations at risk for a detailed ecotoxicological profiling and a post-flood monitoring of organic contamination. The identified sinks of contamination in the floodplain areas can be considered a source for remobilization of pollution in future flood events, which is highly relevant for the receiving Rur River.

Carbon emission from the Lower Ob River floodplain during spring flood

Carbon emission from Arctic rivers constitutes a positive feedback between the climate warming and C cycle. However, in case of rivers with extensive floodplains, the impacts of temporary water bodies and secondary channels on CO2 exchange with atmosphere, compared to the main stem and tributaries, remain strongly understudied. In order to quantify the relative role of various water bodies of the Arctic river basin in the C cycle, the hydrochemical variables and greenhouse gases GHG concentrations and fluxes were measured within the floodplain of the largest Arctic River, Ob, in its low reaches located in the permafrost zone. These included the main stem, secondary channels, tributaries and floodplain lakes sampled over a 900 km north-south transect (25,736 km2 of the main stem and adjacent floodplain area; 7893 km2 water surface) during peak of spring flood (May 2023). In addition to main stem and tributaries, providing less than a half of overall C flux, floodplain lakes and secondary channels acted as important factor of C emission from the floodplain water surfaces. Multi-parametric statistical treatment of the data suggested two main processes of C emission from the Ob River floodplain waters: terrestrial organic matter-rich flooded wetlands (fens) provided elevated pCO2, whereas the sites of possible groundwater discharge in the secondary channels decreased the CO2 fluxes due to more alkaline environments, rich in labile metals and anionic elements.Based on available high-resolution Landsat-8 images, which matched the period of field work, it was found that the total water coverage of the floodplain during spring 2023 was 30 % of overall territory, compared to 18 % during the baseflow. Based on chamber-measured CO2 fluxes (1.56 ± 0.47 g C-CO2 m−2 d−1), overall CO2 emissions during 2 months of the spring flood from the entire Lower Ob River floodplain water surfaces including the main stem amounted to 0.73 ± 0.25 Tg C. Diffuse CH4 flux represented <1 % of total C flux. The main stem of the Ob River accounted for 34 % and 18 % of CO2 and CH4 emissions, respectively, whereas the floodplain lakes provided 59 % and 50 % of CO2 and CH4 emission, respectively. Considering that the low reaches of the Ob River represent >70 % of total river basin floodplain, and that during some years, the entire floodplain can be covered by water, emissions from the river – if assessed solely from summer (July–August) measurements – can be at least 3 times underestimated. It is therefore important to account for extended water surface during high water levels on Arctic rivers when assessing global riverine C emissions.

The role of Nature-Based Solutions for the water flow management in a Mediterranean urban area

Due to climate change and rapid urban sprawl, central Mediterranean regions are subjected to short but intensive storm events resulting in a significant increase of flow rates and runoff volumes in low-lying coastal urban areas. Within the framework of green urban infrastructures (GUIs), a suitable combination of Nature-Based Solutions (NBS) with traditional grey infrastructures should be adopted to mitigate flood risk effects in urban and sub-urban areas contributing at the same time to achieve multiple benefits for both the environment and the community. The aim of this study is (i) to evaluate flood hazard maps for identifying the areas within a Sicilian hydrological river basin (Toscano catchment) with a high risk of flooding by implementing the HEC-RAS model at catchment scale; (ii) to quantify the peak flow and floodplain area reduction; (iii) to assess the effectiveness of small-scale NBS (green roofs, porous pavements, rain gardens and rain barrel), in terms of peak flow and runoff volume reductions, at urban block scale by using the EPA SWMM model Model simulations are performed integrating the hydraulic (HEC-RAS) and hydrological (EPA SWMM) models for return periods of 10, 50 and 200 years. The results showed that the estimated peak flow (m3 s−1) obtained from the simulations performed at catchment scale for each T in the current scenario (without NBS) using HEC-RAS and EPA SWMM models are very close to each other (R2 = 0.99). In addition, the utopian scenario simulation showed the HEC-RAS model sensitivity to CN calibration achieving a peak flow reduction up to about 60% with the floodplain area decreasing up to about 17%. Finally, the model EPA SWMM shows its sensitivity to NBS implementation at urban block scale with a peak flow reduction up to about 16% and a runoff volume (mm) reduction up to about 24%. These reductions decrease as T increases with a higher NBS mitigation effects for the lowest T. The results highlighted that the integration of NBS in urban areas could have hydrological and hydraulic positive effects, particularly in terms of peak flow and runoff volume reduction. Furthermore, the results suggest that small-scale NBS have a potential to be effective to smaller rainfall events, but a combination with large-scale NBS is necessary to cope with extreme events.

Estimating the daily flooding probability by the compound effect of rainfall and tides in an Amazonian metropolis

Belém, the capital of the state of Pará, host of the 30th UN Climate Change Conference (COP30), which is located in the Brazilian Amazon, suffers from flooding caused by rainfall and tides. The objective was to estimate the daily flooding probability in Belém based on the two assumptions, i.e., the compound effect of rainfall and tides and rainfall only. In this case, rainfalls were analysed considering intensity and duration. Thus, it was possible to evaluate the flooding probability for each assumption and propose technological solutions to reduce this probability. Rainfall and tide height data for the 2003 to 2021 period were used. The minimum level causing flooding was defined analysing the compound effect (rainfall + tide height). The effects of rainfall and tides were also separately analysed with the aim of isolating the entry of tides into city canals. The daily flooding probability was estimated based on the study of the a priori probability derived from the ratio between the number of flooding events and the number of possible floods. The results showed that certain areas of Belém-PA could be flooded with a minimum value of rainfall plus tide height is 640.4 mm, if the rainfall intensity reaches at least 30 mm/h. Regarding the rainfall duration, the minimum value of rainfall plus tide height is 1398 mm for flooding to occur if rainfall lasts at least two hours. The flooding events were validated by examining local newspaper reports and photographic records describing and capturing flooding, respectively. The highest daily flooding probability occurred during the wettest period in the city, from January to May. The daily flooding probability was greatly reduced when only rainfall was considered. Thus, if city canals encompass floodgate systems, flood damage could be reduced. A floodgate systems project would be an important COP30 legacy for Belém. This system could help reduce the losses suffered by the poorest populations in Belém, who live in floodplain areas.

SHIFT: a spatial-heterogeneity improvement in DEM-based mapping of global geomorphic floodplains

Abstract. Floodplains are a vital part of the global riverine system. Among all the global floodplain delineation strategies empowered by remote sensing, digital elevation model (DEM)-based delineation is considered to be computationally efficient with relatively low uncertainties, but the parsimonious model struggles with incorporating the basin-level spatial heterogeneity of the hydrological and geomorphic influences into the map. In this study, we propose a globally applicable thresholding scheme for DEM-based floodplain delineation to improve the representation of spatial heterogeneity. Specifically, we develop a stepwise approach to estimate the floodplain hydraulic geometry (FHG) scaling parameters for river basins worldwide at the scale of the level-3 HydroBASINS to best respect the scaling law while approximating the spatial extent of two publicly available global flood maps derived from hydrodynamic modeling. The estimated FHG exponent exhibits a significant positive relationship with the basins' hydroclimatic conditions, particularly in 33 of the world's major river basins, indicating the ability of the approach to capture fingerprints from heterogeneous hydrological and geomorphic influences. Based on the spatially varying FHG parameters, a ∼ 90 m resolution global floodplain map named the Spatial Heterogeneity Improved Floodplain by Terrain analysis (SHIFT) is delineated, which takes the hydrologically corrected MERIT Hydro dataset as the DEM inputs and the height above nearest drainage (HAND) as the terrain attribute. Our results demonstrate that SHIFT validates better with reference maps than both hydrodynamic-modeling- and DEM-based approaches with universal parameters. The improved delineation mainly includes better differentiation between main streams and tributaries in major basins and a more comprehensive representation of stream networks in aggregated river basins. SHIFT estimates the global floodplain area to be 9.91×106 km2, representing 6.6 % of the world's total land area. SHIFT data layers are available at two spatial resolutions (90 m and 1 km), along with the updated parameters, at https://doi.org/10.5281/zenodo.11835133 (Zheng et al., 2024). We anticipate that SHIFT will be used to support applications requiring boundary delineations of the global geomorphic floodplains.

Implication of heavy metal(loid)s contamination for human health and preliminary application of water treatment in floodplain area along Mekong River, Lao PDR

Groundwater is widely used for domestic purposes, especially as a reliable source of drinking water in rural areas of the Lao People’s Democratic Republic (Lao PDR). This preliminary study aims to examine heavy metal(loid)s contamination leading to human health risks while also focusing on a method that can improve drinking water quality in floodplain areas along the Mekong River in Lao PDR. Groundwater and surface water samples were collected during the monsoon season in 2022 in Attapeu and Champasak provinces. Heavy metal(loid)s concentrations and human health risks were investigated using inductively coupled plasma mass spectrometry (ICP-MS) and the USEPA method, respectively. A nanofiltration membrane technique was introduced to optimize the quality of groundwater. Results showed that groundwater quality was significantly poor (p < 0.05), particularly in Attapeu province, with high levels of electrical conductivity, total dissolved solids, and manganese, exceeding WHO standards of 400 µS cm−1, 300 mg L−1, and 80 µg L−1, respectively. With the groundwater ingestion pathway, children were found to be more vulnerable to non-carcinogenic risk than adults (Hazard Quotient, Hazard Index >1), but adults had a higher carcinogenic risk (Incremental Lifetime Cancer Risk >1E-04). The removal of fecal bacteria and heavy metal(loid)s was achieved using the nanofiltration membrane, demonstrating its potential as a practical point-of-use technology to provide cleaner water sources and enhance the health status of Lao residents.

The characteristics of modern flood deposits in the lower reaches of a small watershed and the significance of paleo-flood identification

The mountainous region of central Shandong Province in eastern China is renowned for its high frequency of rainstorms, which often result in devastating flood disasters and have profoundly affected the evolution of local ancient civilizations. To identify ancient flood disaster events, recognizing sediment signatures via multiple indices is important. Here, we investigated the 2018 flood deposits in the Danhe River Basin and sampled short core DH2, on which the grain size, total organic matter (TOM) content, carbonate content, magnetic susceptibility (MS) and pollen were measured. The fine grain size of the flood sedimentary layer reveals that the flood energy in the alluvial plain area is usually weak. The pollen species and concentration and the tree pollen content in the flood layer are significantly greater than those in the soil layer, suggesting that the flood sediment mainly originates from the mountainous areas in the upper reaches of the river, which provides more forest vegetation information. The MS of flood deposits is lower than that of the soil layer, which is mainly related to the intensity of pedogenesis. The research results indicate that the flood sediments in the downstream floodplain areas of small watersheds are predominantly composed of fine-grained components, with characteristics of high loss on ignition, low magnetic susceptibility, high pollen abundance and diverse species. These findings establish a multi-index identification system for paleoflood sedimentation, which has important reference significance for the study of paleoflood sedimentology and hydrology.

Prioritising water-related regional development project ideas based on stakeholder involvement activities: A case study from Szigetköz, Hungary

Szigetköz—a large island of the Danube in Hungary—is attracting a new wave of interest in water-related regional development projects from the public and private sectors alike. The revived interest in the Szigetköz floodplain area, which has historically endured the adverse effects of large-scale water management initiatives, draws attention to the necessity for careful consideration and the active involvement of local stakeholders in the decision-making process.In our research, we conducted various stakeholder engagement activities, including interviews, questionnaires, and workshops. These activities helped define the problems and objectives of each stakeholder group. Through collaborative consultations, we gathered over 100 proposed water related development project ideas. Additionally, to address key issues in project development and selection, we evaluated the integrative potential of each proposed project, considering the number of distinct water management issues it addressed. We also assigned an attitude score to each project, derived from the diverse objectives of various stakeholder groups, and analysed these quantities using a multiple-criteria analysis.This paper details a novel approach to assess and rank the proposed water-related regional development project ideas based on the calculated integrative potential and attitude scores. The goal was to prioritise and further develop these proposed projects to benefit Szigetköz and its surrounding areas.Main results of the study have shown the average project scored between 0.33–0.50 in integrative potential out of a maximum of 1.00 For positive attitude score the average was between 0.28–0.43, out of a maximum of 1.00 while for the negative attitude score the average project scored between -0.14–0.00 out of a minimum of -1.00.The ranking of projects that was based on these scores, highlighted three types of proposed projects that need to be further developed in different ways. The top-ranked positive attitude integrative projects need cost-benefit calculations involving all ecosystem services to justify their economic sustainability. Top-ranked opposing attitude integrative projects need conflict resolution to be socially sustainable. Finally, project ideas that scored low on integrative potential need to be developed to make use of blue-green infrastructure, and circular economical advancements to foster their environmental sustainability.

Recycling Selected Wetlands’ Sediments for a Vegetable Crop Cultivation in Terrestrial Ecosystem of a Humid Region

This study aimed to evaluate the selected wetlands' sediments regarding physicochemical attributes including heavy metals (HMs), and their potentiality to be used in crop cultivation with or without mixing with different generic farmers' field soils in the upland. Forty geo-referenced sediment samples were collected from each study site (n=3), and mixed to get three separate composite samples for mineral nutrients, HMs analyses and experimentation. Two pot experiments were conducted following Completely Randomized Design (CRD) with three replicates using farmers’ field soils (FFS) Gleysols and Cambisols to grow amaranth. The treatments were: T0: FFS; T1: FFS + wetland sediment of hilly area I (1:1); T2: FFS + wetland sediment of hilly area II (1:1); T3: FFS + wetland sediment of a floodplain area (1:1); T4: wetland sediment of hilly area I; T5: wetland sediment of hilly area II; T6: wetland sediment of a floodplain area. Regarding nutrient elements, exchangeable K, extractable P, Ca, and Zn were observed higher in wetland sediment of hilly area II except organic carbon (OC). Only Cd, Pb, and Ni were individually found higher than the maximum permissible addition for all wetland sediments, but all HMs collectively posed no “ecological risk”. The highest values of the plant growth index of amaranth were observed for T5 treatment. Moreover, the highest total fresh and dry biomasses were found in T5 treatment. The highest nutrient uptake was observed in T5 treatment for the most of nutrients. Studied wetlands’ soil materials, OC, and nutrients could be used to benefit upland crop cultivation.