Seasonal variability of dissolved and particulate methylmercury（F-MeHg, P-MeHg） concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005–2006, ...Seasonal variability of dissolved and particulate methylmercury（F-MeHg, P-MeHg） concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005–2006, to understand the MeHg exchanges between these aquatic systems. In the oxic white water lakes, with neutral pH, high F-MeHg and P-MeHg concentrations were measured during the rising water stage（0.70 ± 0.37 pmol/L, n = 26） and flood peak（14.19 ± 9.32 pmol/g, n = 7） respectively, when the Amazon River water discharge into the lakes was at its maximum. The lowest mean values were reported during the dry season（0.18 ± 0.07 pmol/L F-MeHg, n = 10 and 1.35 ± 1.24 pmol/g P-MeHg, n = 8）, when water and suspended sediments were outflowing from the lakes into the River. In these lakes,the MeHg concentrations were associated to the aluminium and organic carbon/nitrogen changes. In the black water lakes, with acidic pH and reducing conditions, elevated MeHg concentrations were recorded（0.58 ± 0.32 pmol/L F-MeHg, n = 16 and 19.82 ± 15.13 pmol/g PMeHg, n = 6）, and correlated with the organic carbon and manganese concentrations. Elevated values of MeHg partition coefficient（4.87 〈 Kd〈 5.08 log（L/kg） indicate that MeHg is mainly transported associated with the particulate phase. The P-MeHg enrichment detected in all lakes suggests autochthonous MeHg inputs from the sediments into the water column. The MeHg mass balance showed that the Curuai floodplain is not the source of P-MeHg for the Amazon River.展开更多
To understand the pollution characteristics and distributions of microplastics in the Dagu River,an important inland river that flows to Jiaozhou Bay,the abundance,particle size,shape,color,and polymer type of micropl...To understand the pollution characteristics and distributions of microplastics in the Dagu River,an important inland river that flows to Jiaozhou Bay,the abundance,particle size,shape,color,and polymer type of microplastics in the surface waters and floodplain sediments were investigated.The results showed that the abundance of microplastics in the surface waters varied between 0.68 and 3.96 items L^(−1).The abundance of microplastics in the floodplain sediments varied between 115.5 and 495 items kg^(−1).The distribution of microplastics in the river has obvious characteristics:1)The abundance of microplastics downstream was significantly higher than that upstream.2)The abundance of microplastics decreased significantly in the estuary.3)The abundance of microplastics was higher in densely populated areas.4)Factors such as effluent discharge from sewage treatment plants and inflow of tributaries affect the abundance of microplastics in rivers.The main polymer types of microplastics were polypropylene(PP),polyethylene(PE),and polyvinyl chloride(PVC).Both the abundance and polymer types of microplastics show a positive correlation between the surface waters and floodplain sediment samples,indicating that the microplastics in surface waters and floodplain sediments come from the same source.The present study demonstrates that the abundance,distribution,and sources of microplastics might be affected by geology,hydrogeology,land use types,and anthropogenic activities.This study provides basic data for the study of microplastics in rivers and provides a reference for the establishment of microplastic control measures.展开更多
Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matter...Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.展开更多
The Yangtze River floodplain is critical for migratory waterbirds along the East Asian-Australasian Flyway (EAAF). Greater awareness of its global importance is urgently needed to ensure waterbird populations remain i...The Yangtze River floodplain is critical for migratory waterbirds along the East Asian-Australasian Flyway (EAAF). Greater awareness of its global importance is urgently needed to ensure waterbird populations remain in favourable conservation status, as well as the enhancement of wider wetland biodiversity within this region. The designation of protected wetland areas and building a green ecological corridor in the Yangtze floodplain is now becoming a critical issue of interest to the Chinese government. Priority sites in this area were identified based on the criteria used to identify sites that qualify as Wetlands of International Importance (Ramsar Sites) and Important Bird and Biodiversity Areas (IBAs) by using multi-source data. The results show that 140 of the sites surveyed are priority sites. The Importance Index (/) for the whole floodplain decreased slightly from 2001–2005 and an unbalanced distribution pattern is evident with Jiangxi and Hunan provinces significantly higher than the other provinces in the floodplain. Although more than 60% of the priority sites are currently located outside protected areas, the average Conservation Effectiveness Index (C) of the whole floodplain is 75.6%, which suggests the coverage of protected areas for most wintering waterbird population is reasonable. Conservation of the Yangtze River floodplain needs to be further strengthened due to declining waterbird abundances and the mismatch between the distribution of protected areas and their importance for wintering waterbirds. A comprehensive system for priority site identification and protection and scientific review is needed. Multi-sourced data from regular, systematic and coordinated monitoring of waterbird distribution and abundance across the EAAF, as well as national scale citizen science programmes are also critically important.展开更多
River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in ...River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in a total of 135 floodplain waterbodies (rivers, diversion canals, ponds, irrigation ditches, paddy fields, and wetlands) in the Chao Phraya River Basin in rainy (September 2014) and dry (March 2015) seasons. Factors affecting fish species richness in each type of waterbody were analyzed using generalized linear mixed models. Floodplain area around each surveyed waterbody was a major factor determining fish species richness in rivers, diversion canals, and ponds in the region. The contribution of floodplain area was equivalent to that of hydrology (current velocity, water depth) and water quality (dissolved oxygen, turbidity) in the waterbodies. The population of juvenile fishes was increased in temporarily connected floodplain waterbodies to main rivers compared with isolated waterbodies, and fluvial and lacustrine fishes were observed in the temporary inundated floodplain waterbodies during the rainy season. The high dependence of fish species richness on floodplain area in the region appeared to be a result of the use of inundated floodplains by fish species to forage and breed. Our results highlight the impact of flood control measures that reduces floodplain area. These measures must be reviewed to ensure the conservation of fish biodiversity in the Chao Phraya River Basin, one of the world’s most threatened floodplain systems.展开更多
Background:In the face of continued degradation and loss of wetlands in the Yangtze River floodplain(YRF),there is an urgent need to monitor the abundance and distribution of wintering waterbirds.To understand fully o...Background:In the face of continued degradation and loss of wetlands in the Yangtze River floodplain(YRF),there is an urgent need to monitor the abundance and distribution of wintering waterbirds.To understand fully observed annual changes,we need to monitor demographic rates to understand factors affecting global population size.Annual reproduction success contributes to dynamic changes in population size and age structure,so an assessment of the juvenile ratio(i.e.first winter birds as a proportion of total number aged)of overwintering waterbirds can be an important indicator of the reproductive success in the preceding breeding season.Methods:During 2016-2019,we sampled juvenile ratios among 10 key waterbird species from the wetlands in the YRF.Based on these data,we here attempt to establish a simple,efficient,focused and reliable juvenile ratio monitoring scheme,to assess consistently and accurately relative annual breeding success and its contribution to the age structure among these waterbird species.Results:We compared juvenile ratio data collected throughout the winter and found that the optimal time for undertaking these samples was in the early stages of arrival for migratory waterbirds reaching their wintering area(early to mid-December).We recommend counting consistently at key points(i.e.those where>1%biogeographical flyway population were counted)at sites of major flyway importance(Poyang Lake,East Dongting Lake,Shengjin Lake,Caizi Lake,Longgan Lake and Chen Lake).Based on this,the error rate of the programme(155 planned points,the count of 10 waterbird species is 826-8955)is less than 5%.Conclusions:We established a juvenile ratio monitoring programme for 10 key waterbird species in the wetlands of the YRF,and discuss the feasibility and necessity of implementing such a future programme,and how to use these data in our monitoring and understanding of the population dynamics of these waterbird populations.展开更多
Rice production in the tidal floodplain of southern Bangladesh is constrained by uncontrolled water. In absence of high yielding varieties suitable for tidal floodplain, farmers grow low yielding indigenous cultivars ...Rice production in the tidal floodplain of southern Bangladesh is constrained by uncontrolled water. In absence of high yielding varieties suitable for tidal floodplain, farmers grow low yielding indigenous cultivars of tall plant type. This paper reports the effect of agronomic management on the yield and yield components of an indigenous rice cultivar, Sadamota. The trial was conducted in 10 farmers’ plots located widely apart in two upazila (sub-districts)—Jhalakati and Rajapur. 45 d and 60 d old seedlings were transplanted either in rows at 40 cm × 20 cm spacing or following farmers’ traditional practice of random planting. Transplanting 60 d old seedlings produced 14% higher yield compared with 45 d old seedlings. Transplanting in rows also increased grain yield by 12%. The yield increase was associated with hill density, the number of effective tillers per hill and the number of spikelets per panicle.展开更多
Residents along the shoreline of the Orashi River have yearly been displaced and recorded loss of lives,farmland,and infrastructures.The Government’s approach has been the provision of relief materials to...Residents along the shoreline of the Orashi River have yearly been displaced and recorded loss of lives,farmland,and infrastructures.The Government’s approach has been the provision of relief materials to the victims instead of implementing adequate control measures.This research employs Shuttle Radar Topographic Mission and Google Earth imagery in developing a 3D floodplain map using ArcGIS software.The result indicates the drainage system in the study area is dendritic with catchment of 79 subbasins and 76 pour point implying the area is floodplain.Incorporating the 3D slope which reveals that>8 and<8 makes up 1.15%and 98.85%of the study area respectively confirms the area is a floodplain.Aspect indicate west-facing slope are dark blue,3D hillshade indicate yellow is very low area and the high area is pink and also the buffer analysis result reveals waterbodies reflecting blue with an estimated area of 1.88 km2,yellow indicate 0.79 km2 of the shoreline,red indicate 0.81 km2 of the minor floodplain and pink contain 0.82 km2 with the length of 32.82 km.The result from google earth image in 2007 indicate absent of settlement,2013 indicate minimal settlement and 2020 indicate major settlement in the study area when correlated with 3D Floodplain mapping before and during the flood in other to analyze and manage flooding for further purpose and the majority of the area are under seize with flood like in 2020.Therefore,Remote Sensing and GIS techniques are useful for Floodplain mapping,risk analysis for control measures for better flood management.展开更多
Mapping floods is important for policy makers to make timely decisions in regards to emergency responses and future planning.It is therefore crucial to develop a rapid inundation modelling framework to map flood inund...Mapping floods is important for policy makers to make timely decisions in regards to emergency responses and future planning.It is therefore crucial to develop a rapid inundation modelling framework to map flood inundation.This study develops an airborne scanning laser altimetry(LiDAR)digital elevation model(DEM)based Rapid flood Inundation Modelling framework(LiDAR-RIM)for assessment of inundation extent,depth,volume and duration for flood events.The modelling framework has been applied to the mid-Murrumbidgee region in the southeast Murray-Darling Basin,Australia for two flood events occurred in December 2010 and March 2012.The inundation extents estimated using this methodology compared well to those obtained from two Landsat ETM+images,demonstrating suitability and applicability of this method.For testing possibility of larger area application,the framework also uses 30-m resolution shuttle radar topography mission(SRTM)-DEM to replace Li DAR-DEM for the same modelling.The inundation extents obtained by using the SRTM-DEM are smaller than those obtained using the Li DAR-DEM,especially for large flood events.A possible reason is that the river cross sections obtained from the SRTM-DEM are not accurate enough for inundation modelling.The Li DAR-RIM has an advantage for process modelling and scenario modelling under future climatic conditions.展开更多
Recent advances in hydraulic modeling create improved methodology to accurately predict the extent of floodplain map in order to assist policy makers to develop flood hazard mitigation measures and timely inform the l...Recent advances in hydraulic modeling create improved methodology to accurately predict the extent of floodplain map in order to assist policy makers to develop flood hazard mitigation measures and timely inform the local communities with the flood risk alerts.However,accurate prediction of the inundation map also depends on the spatial resolution of the topographic data.In this study,we developed a novel high-resolution modeling framework for Nashwaak River watershed,New Brunswick,Canada to capture significant flooding along the banks of the river for the two historic flood events and accurately map the floodplains for both the gauged and ungauged areas of the watershed.The model is based on HEC-RAS(US Army Corps of Engineers Hydrologic Engineering Center River Analysis System)hydraulic model and the topographic data were generated from high-resolution LiDAR data of~0.5 m.The model runs were driven by observed flow conditions applied at the boundary and the framework is based on different spatial resolution to determine the effect of spatial resolution on the predicted inundation.We validated the model simulated water surface elevation with the observed data and the model reproduces reasonably good skill score.Results from the numerical simulation suggest that apart from the strength of the stream velocity,design of the modeling framework plays an important role in determining the inundation depth as well as the maximum flooding extent.展开更多
Floods are essential for the regeneration and growth of floodplain forests in arid and semiarid regions. However, river flows, and especially flood flows, have decreased greatly with the increase of water diversion fr...Floods are essential for the regeneration and growth of floodplain forests in arid and semiarid regions. However, river flows, and especially flood flows, have decreased greatly with the increase of water diversion from rivers and/or reservoir regulation, resulting in severe deterioration of floodplain ecosystems. Estimation of the flood stage that will inundate the floodplain forest is necessary for the forest＇s restoration or protection. To balance water use for economic purposes and floodplain forest protection, the inundated forest width method is proposed for estimating the minimum flood stage for floodplain forests from the inundated forest width-stage curve. The minimum flood stage is defined as the breakpoint of the inundated forest width-stage curve, and is determined directly or analytically from the curve. For the analytical approach, the problem under consideration is described by a multi-objective optimization model, which can be solved by the ideal point method. Then, the flood flow at the minimum flood stage （minimum flood flow）, which is useful for flow regulation, can be calculated from the stage-discharge curve. In order to protect the forest in a river floodplain in a semiarid area in Xinjiang subject to reservoir regulation upstream, the proposed method was used to determine the minimum flood stage and flow for the forest. Field survey of hydrology, topography, and forest distribution was carried out at typical cross sections in the floodplain. Based on the survey results, minimum flood flows for six typical cross sections were estimated to be between 306 m3/s and 393 m3/s. Their maximum, 393 m3/s, was considered the minimum flood flow for the study river reach. This provides an appropriate flood flow for the protection of floodplain forest and can be used in the regulation of the upstream reservoir.展开更多
Floodplain forests with regular flooding regimes are the largest natural retentions areas in Croatia and are important as natural habitats for ungulates.The aim of this study was to determine the scale of mortality ca...Floodplain forests with regular flooding regimes are the largest natural retentions areas in Croatia and are important as natural habitats for ungulates.The aim of this study was to determine the scale of mortality caused by flooding within these forests.Over a 10-year period,data on ungulate mortality(red deer,roe deer and wild boar),flood duration and flooded surface area were recorded.The study was conducted in primary(Posavske Sume—RET I)and secondary(Opeke II—RET II)retention areas within Lonjsko Polje Nature Park(Sava River region,Croatia).The longest flood period and the largest flooded surface area were recorded in RET I.Total ungulate mortality was749 individuals,with 482 individuals in RET I and 267 individuals in RET II,predominantly wild boar.Flood mortality did not differ by gender.The highest mortality of wild boar was recorded for the juvenile and yearling ageclasses.Low mortality of red and roe deer can be attributed to their body size and ecological niches.Differences in mortality between the primary and secondary retention areas corresponded to differences in flood regimes,flood column heights and micro relief structures.In both retention areas,wild boar mortality and flood duration,i.e.flooded surface area,were positively correlated.Because the growth rate of the analysed ungulate populations was higher than the recorded mortality,no long-term effect of floods is expected on species abundance in these areas.展开更多
An exploratory study of the traditional homestead forest of two different religious groups (Hindu and Muslim) in one selected floodplain area of Bangladesh was conducted over a period of six months from January to Jun...An exploratory study of the traditional homestead forest of two different religious groups (Hindu and Muslim) in one selected floodplain area of Bangladesh was conducted over a period of six months from January to June 2002. The species' (both tree and shrub) preferences, similarities, use and sources of planting materials, spacing and location of species in the homesteads of both Hindu and Muslim communities were studied. It was found thatMangifera indica as tree species andOcimum sanctum as shrub species were the best preferred species of the Hindu community.Artocarpus heterophyllus as tree species andLawsonia inermis as shrub species were found best preferred by the Muslim community. Floristic similarities between the two groups were found 86.57% in tree species and 78.48% in shrub species. Both seed and seedlings of tree and shrub species as planting materials were used by the highest percentage of both the religious communities. For tree species, homegarden was reported to be the highest source (39%) and for shrub species, nature was the highest source (40%), which was found in the Hindu community. Key words Species preferences - Species similarity - Planting materials - Hindu - Muslim - Homestead forests - Floodplain area - Bangladesh CLC number S72 Document code A Biography: Md. Danesh Miah (1971): male, Assistant Professor in the Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong 4331, Bangladesh.Responsible editor: Chai Ruihai展开更多
Due to the regulation of the river Volga flow, expanding of the territories intended for construction and development of agriculture wetlands Volga-Akhtuba floodplain are being significantly transformed and are losing...Due to the regulation of the river Volga flow, expanding of the territories intended for construction and development of agriculture wetlands Volga-Akhtuba floodplain are being significantly transformed and are losing many of their qualities. Non-regulated loads lead to the break of natural physical and chemical characteristics of water bodies, loss of biodiversity, degradation of structure and functions of biological communities and, as a result, to decreasing of potential ecosystem services. Restoration of the lost qualities of water ecosystems is a key factor in increasing sustainability of reclaimed landscapes and creating comfortable conditions for living of locals and their economic activity. On the territory of the biosphere reserve “Nature park” “Volga-Akhtuba floodplain” a number of model sites were defined in order for research projects and practical work on restoration of degraded landscapes to be executed. The widest range of the lost ecosystem qualities is being restored during work on Lake Zapornoye. Restoration of ecosystem functions is being implemented according to the main economic activities carried out in this area. Ecosystem services of the area are specified in accordance with its functional purpose. The existing landscape and ecology conditions have been studied and estimated to see if the planned ecosystem services can be provided. The project suggests the following activities: restoration of hydro-morphological characteristics, reconstruction of habitats for biodiversity and their ecosystem services, improvement to restore and preserve recreational qualities of landscape. The project includes the monitoring the effectiveness of restoration. Monitoring program is based on indices of environmental assessment.展开更多
The small-scale fishermen in the north-eastern floodplains are one of the most vulnerable communities of Bangladesh due to their limited income.This study assessed their livelihood status using a sustainable livelihoo...The small-scale fishermen in the north-eastern floodplains are one of the most vulnerable communities of Bangladesh due to their limited income.This study assessed their livelihood status using a sustainable livelihood framework and employed a multiple regression model to evaluate factors influencing their earnings.Primary data were collected from fishermen’s households in Tanguar Haor and Hakaluki Haor through direct interviews.Results revealed that these households lacked human capital,had poor sanitation facilities and suffered from frequent diseases.Their income is very limited as they lack training on other socioeconomic activities to comple-ment their livelihood grounded on fishing.Hence,their financial capital was very deficient and ranked lowest among other livelihood capitals.Fishermen’s major physical assets were the boats used for group and individual fishing.These small-scale fishermen had limited involvement with local administration,and around half of them were members of various NGOs.Women of these households had low participation in fishing or other income activities.The income of the fishermen was influenced by their age,fish catch per day,training and NGO mem-bership.To increase the earnings and improve the livelihood status of small-scale fishers in the floodplain,this study suggests providing training on complementary income generating activities,improving sanitation facilities and providing additional government and non-government support.展开更多
Soil minerals study is vital in terms of investigating the major soil forming compounds and to find out the fate of minor and trace elements in soils. It is also essential for the soil-plant interaction purpose. To id...Soil minerals study is vital in terms of investigating the major soil forming compounds and to find out the fate of minor and trace elements in soils. It is also essential for the soil-plant interaction purpose. To identify soil mineral phases especially clay minerals, X-ray diffraction (XRD) has been a popular technique. The clay mineralogical information of soils in Bangladesh is limited, especially in Ganges flood plain region (Agro Ecological Zone (AEZ) 12 and 13). Therefore, to overcome this limitation, in this study, we performed XRD analysis of <2 mm fractions soil samples of AEX 12 and 13. However, identifying mineralogical phases by XRD in <2 mm fractions soils is not so straight-forward due to many practical problems. We fully matched only two mineralogical phases in all the soil samples which is quartz and potassium-Aluminum-Silicate. However, the full XRD peaks indicate that more minerals are also present, but due to heterogeneity of soils samples, it is difficult to find other minerals phases by only XRD peak of <2 mm fractions. Therefore, to find more information about mineralogical phases, we performed XRF analysis that provides the elemental composition of minerals phase as oxide. XRF analysis indicated the presence of secondary minerals like illite and chlorite. The presence of high percentage Fe oxide not only indicated the iron mineral phase (goethite and ferrihydrite) but also indicated iron rich high charge smectite minerals (beidellite). The presence of iron rich smectite minerals in the Ganges sediments reported in several previous studies. Thus, we concluded that only XRD in <2 mm fractions of soils is not adequate to identify the mineralogical phases of soil samples. Others analyses like XRF, XRD in <2 μm fractions will be necessary to locate an entire image of soil mineralogical phases.展开更多
No simple solution to flood prevention is accessible. This research provides a brief summary of the hydrologic and hydraulic methodology that can be used to develop specific details that integrated the flood informati...No simple solution to flood prevention is accessible. This research provides a brief summary of the hydrologic and hydraulic methodology that can be used to develop specific details that integrated the flood information tool. It permits rapid analysis of a wide variety of stream discharge data and topographic mapping to avoid the flood hazard over entire floodplain boundaries. This paper focuses on the water floodplain hazard in Wadi Asla-Jaddah-Saudi Arabia. The most common type of rainfall in the study area is that accompanied by thunderstorms, which usually fall during the winter season as well as in the spring. The primarily evaluation of this problem and the solution is contemplate. The more essential and ＂doable＂ elements of a solutions and recommendations are discussed in this research.展开更多
The actual situation of the Tisza Valley traditionally used for land farming is basically determined by the consequences of the river regulation of the nineteenth century which aimed at the extension of the intensive ...The actual situation of the Tisza Valley traditionally used for land farming is basically determined by the consequences of the river regulation of the nineteenth century which aimed at the extension of the intensive agriculture, by the extreme water regime of alternating periods of flood showing a deteriorating trend and drought related to the climatic change; and by several environmental problems induced mainly by the land use. The objective of the article is to prove the regional advantages of a proposed technical solution to mitigate the flood risk with a special regard to the land cover. Hydrodynamic modeling results prove that the best technical solution is given by a combination of different strategies containing the inundation of deep floodplains-areas regularly covered by water before the river regulation works and, globally, by an important mitigation of flood damages, the costs of solution would be surely covered in the longterm. By means of its natural-resembling operation, the regular water cover would allow a multiple use of water, contributing to the solution of the simultaneously existing aridity problem, and, the development of the floodplain landscape management would help improve the ecological and the economical upgrading of the region.展开更多
The GEF-WB Nutrient Reduction project aims to reduce the phosphorus inputs of the Black Sea from the Danube by means of different interventions. Hungary takes part of this project by enhancing the nutrient trapping ca...The GEF-WB Nutrient Reduction project aims to reduce the phosphorus inputs of the Black Sea from the Danube by means of different interventions. Hungary takes part of this project by enhancing the nutrient trapping capacity of the Gemenc and Beda-Karapancsa wetlands （GBK） which can be found on the premises of the Danube Drava National Park along the Danube River in Southern Hungary. Due to anthropogenic influences, less of small floods reach the oxbows of the area than some decades before which has a negative effect on the ecosystem. The objective of the study is to predict the nutrient reduction capacity of the Gemenc-B6da-Karapancsa water system and to make a proposal to increase this capacity. Although the floodplain vegetation has a huge nutrient intake capacity, this is limited by the fact that the floodplain is not always covered by the water of the river Danube. For that reason, a combination of hydrodynamic modelling, flood probability calculation and an estimation of suspended solids settling constitute the base of this study. The main course taken into account is the settling of suspended solids and the ratio of total nitrogen and total phosphorus to the mass of sediment is determined by local measurement results.展开更多
基金This work was supported by the Yellow River Engineering Consulting Co.,Ltd.(Grant No.2019GS007-WW03/20)the State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(Grant No.SKL2020ZY10).
基金a PhD grant delivered by the Alban Programthe European Union Program of High Level Scholarship for Latin American, scholarship no.E04D0445592BR
文摘Seasonal variability of dissolved and particulate methylmercury（F-MeHg, P-MeHg） concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005–2006, to understand the MeHg exchanges between these aquatic systems. In the oxic white water lakes, with neutral pH, high F-MeHg and P-MeHg concentrations were measured during the rising water stage（0.70 ± 0.37 pmol/L, n = 26） and flood peak（14.19 ± 9.32 pmol/g, n = 7） respectively, when the Amazon River water discharge into the lakes was at its maximum. The lowest mean values were reported during the dry season（0.18 ± 0.07 pmol/L F-MeHg, n = 10 and 1.35 ± 1.24 pmol/g P-MeHg, n = 8）, when water and suspended sediments were outflowing from the lakes into the River. In these lakes,the MeHg concentrations were associated to the aluminium and organic carbon/nitrogen changes. In the black water lakes, with acidic pH and reducing conditions, elevated MeHg concentrations were recorded（0.58 ± 0.32 pmol/L F-MeHg, n = 16 and 19.82 ± 15.13 pmol/g PMeHg, n = 6）, and correlated with the organic carbon and manganese concentrations. Elevated values of MeHg partition coefficient（4.87 〈 Kd〈 5.08 log（L/kg） indicate that MeHg is mainly transported associated with the particulate phase. The P-MeHg enrichment detected in all lakes suggests autochthonous MeHg inputs from the sediments into the water column. The MeHg mass balance showed that the Curuai floodplain is not the source of P-MeHg for the Amazon River.
基金financially supported by the National Major Special Project for Water Pollution Treatment and Control ‘Technology Integration of Watershed Ecological Function Zoning Management’ Project (No. 2017ZX073 01-001)the National Key Research and Development Program of China (No. 2018YFC1407601)。
文摘To understand the pollution characteristics and distributions of microplastics in the Dagu River,an important inland river that flows to Jiaozhou Bay,the abundance,particle size,shape,color,and polymer type of microplastics in the surface waters and floodplain sediments were investigated.The results showed that the abundance of microplastics in the surface waters varied between 0.68 and 3.96 items L^(−1).The abundance of microplastics in the floodplain sediments varied between 115.5 and 495 items kg^(−1).The distribution of microplastics in the river has obvious characteristics:1)The abundance of microplastics downstream was significantly higher than that upstream.2)The abundance of microplastics decreased significantly in the estuary.3)The abundance of microplastics was higher in densely populated areas.4)Factors such as effluent discharge from sewage treatment plants and inflow of tributaries affect the abundance of microplastics in rivers.The main polymer types of microplastics were polypropylene(PP),polyethylene(PE),and polyvinyl chloride(PVC).Both the abundance and polymer types of microplastics show a positive correlation between the surface waters and floodplain sediment samples,indicating that the microplastics in surface waters and floodplain sediments come from the same source.The present study demonstrates that the abundance,distribution,and sources of microplastics might be affected by geology,hydrogeology,land use types,and anthropogenic activities.This study provides basic data for the study of microplastics in rivers and provides a reference for the establishment of microplastic control measures.
基金Key Project of Chinese Academy of Sciences, No.ZKHZ-3-06
文摘Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.
基金Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23040203National Natural Science Foundation of China,No.41701212STS Project of Chinese Academy of Sciences,No.KFJ-SW-YW026。
文摘The Yangtze River floodplain is critical for migratory waterbirds along the East Asian-Australasian Flyway (EAAF). Greater awareness of its global importance is urgently needed to ensure waterbird populations remain in favourable conservation status, as well as the enhancement of wider wetland biodiversity within this region. The designation of protected wetland areas and building a green ecological corridor in the Yangtze floodplain is now becoming a critical issue of interest to the Chinese government. Priority sites in this area were identified based on the criteria used to identify sites that qualify as Wetlands of International Importance (Ramsar Sites) and Important Bird and Biodiversity Areas (IBAs) by using multi-source data. The results show that 140 of the sites surveyed are priority sites. The Importance Index (/) for the whole floodplain decreased slightly from 2001–2005 and an unbalanced distribution pattern is evident with Jiangxi and Hunan provinces significantly higher than the other provinces in the floodplain. Although more than 60% of the priority sites are currently located outside protected areas, the average Conservation Effectiveness Index (C) of the whole floodplain is 75.6%, which suggests the coverage of protected areas for most wintering waterbird population is reasonable. Conservation of the Yangtze River floodplain needs to be further strengthened due to declining waterbird abundances and the mismatch between the distribution of protected areas and their importance for wintering waterbirds. A comprehensive system for priority site identification and protection and scientific review is needed. Multi-sourced data from regular, systematic and coordinated monitoring of waterbird distribution and abundance across the EAAF, as well as national scale citizen science programmes are also critically important.
文摘River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in a total of 135 floodplain waterbodies (rivers, diversion canals, ponds, irrigation ditches, paddy fields, and wetlands) in the Chao Phraya River Basin in rainy (September 2014) and dry (March 2015) seasons. Factors affecting fish species richness in each type of waterbody were analyzed using generalized linear mixed models. Floodplain area around each surveyed waterbody was a major factor determining fish species richness in rivers, diversion canals, and ponds in the region. The contribution of floodplain area was equivalent to that of hydrology (current velocity, water depth) and water quality (dissolved oxygen, turbidity) in the waterbodies. The population of juvenile fishes was increased in temporarily connected floodplain waterbodies to main rivers compared with isolated waterbodies, and fluvial and lacustrine fishes were observed in the temporary inundated floodplain waterbodies during the rainy season. The high dependence of fish species richness on floodplain area in the region appeared to be a result of the use of inundated floodplains by fish species to forage and breed. Our results highlight the impact of flood control measures that reduces floodplain area. These measures must be reviewed to ensure the conservation of fish biodiversity in the Chao Phraya River Basin, one of the world’s most threatened floodplain systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.31870369,31970433)China Biodiversity Observation Networks(Sino BON)+1 种基金Innovative Research Group Project of the National Natural Science Foundation of China(CN)No.31670424。
文摘Background:In the face of continued degradation and loss of wetlands in the Yangtze River floodplain(YRF),there is an urgent need to monitor the abundance and distribution of wintering waterbirds.To understand fully observed annual changes,we need to monitor demographic rates to understand factors affecting global population size.Annual reproduction success contributes to dynamic changes in population size and age structure,so an assessment of the juvenile ratio(i.e.first winter birds as a proportion of total number aged)of overwintering waterbirds can be an important indicator of the reproductive success in the preceding breeding season.Methods:During 2016-2019,we sampled juvenile ratios among 10 key waterbird species from the wetlands in the YRF.Based on these data,we here attempt to establish a simple,efficient,focused and reliable juvenile ratio monitoring scheme,to assess consistently and accurately relative annual breeding success and its contribution to the age structure among these waterbird species.Results:We compared juvenile ratio data collected throughout the winter and found that the optimal time for undertaking these samples was in the early stages of arrival for migratory waterbirds reaching their wintering area(early to mid-December).We recommend counting consistently at key points(i.e.those where>1%biogeographical flyway population were counted)at sites of major flyway importance(Poyang Lake,East Dongting Lake,Shengjin Lake,Caizi Lake,Longgan Lake and Chen Lake).Based on this,the error rate of the programme(155 planned points,the count of 10 waterbird species is 826-8955)is less than 5%.Conclusions:We established a juvenile ratio monitoring programme for 10 key waterbird species in the wetlands of the YRF,and discuss the feasibility and necessity of implementing such a future programme,and how to use these data in our monitoring and understanding of the population dynamics of these waterbird populations.
文摘Rice production in the tidal floodplain of southern Bangladesh is constrained by uncontrolled water. In absence of high yielding varieties suitable for tidal floodplain, farmers grow low yielding indigenous cultivars of tall plant type. This paper reports the effect of agronomic management on the yield and yield components of an indigenous rice cultivar, Sadamota. The trial was conducted in 10 farmers’ plots located widely apart in two upazila (sub-districts)—Jhalakati and Rajapur. 45 d and 60 d old seedlings were transplanted either in rows at 40 cm × 20 cm spacing or following farmers’ traditional practice of random planting. Transplanting 60 d old seedlings produced 14% higher yield compared with 45 d old seedlings. Transplanting in rows also increased grain yield by 12%. The yield increase was associated with hill density, the number of effective tillers per hill and the number of spikelets per panicle.
文摘Residents along the shoreline of the Orashi River have yearly been displaced and recorded loss of lives,farmland,and infrastructures.The Government’s approach has been the provision of relief materials to the victims instead of implementing adequate control measures.This research employs Shuttle Radar Topographic Mission and Google Earth imagery in developing a 3D floodplain map using ArcGIS software.The result indicates the drainage system in the study area is dendritic with catchment of 79 subbasins and 76 pour point implying the area is floodplain.Incorporating the 3D slope which reveals that>8 and<8 makes up 1.15%and 98.85%of the study area respectively confirms the area is a floodplain.Aspect indicate west-facing slope are dark blue,3D hillshade indicate yellow is very low area and the high area is pink and also the buffer analysis result reveals waterbodies reflecting blue with an estimated area of 1.88 km2,yellow indicate 0.79 km2 of the shoreline,red indicate 0.81 km2 of the minor floodplain and pink contain 0.82 km2 with the length of 32.82 km.The result from google earth image in 2007 indicate absent of settlement,2013 indicate minimal settlement and 2020 indicate major settlement in the study area when correlated with 3D Floodplain mapping before and during the flood in other to analyze and manage flooding for further purpose and the majority of the area are under seize with flood like in 2020.Therefore,Remote Sensing and GIS techniques are useful for Floodplain mapping,risk analysis for control measures for better flood management.
基金CAS Talents Program and IGSNRR Supporting Fund,No.YJRCPT2019-101。
文摘Mapping floods is important for policy makers to make timely decisions in regards to emergency responses and future planning.It is therefore crucial to develop a rapid inundation modelling framework to map flood inundation.This study develops an airborne scanning laser altimetry(LiDAR)digital elevation model(DEM)based Rapid flood Inundation Modelling framework(LiDAR-RIM)for assessment of inundation extent,depth,volume and duration for flood events.The modelling framework has been applied to the mid-Murrumbidgee region in the southeast Murray-Darling Basin,Australia for two flood events occurred in December 2010 and March 2012.The inundation extents estimated using this methodology compared well to those obtained from two Landsat ETM+images,demonstrating suitability and applicability of this method.For testing possibility of larger area application,the framework also uses 30-m resolution shuttle radar topography mission(SRTM)-DEM to replace Li DAR-DEM for the same modelling.The inundation extents obtained by using the SRTM-DEM are smaller than those obtained using the Li DAR-DEM,especially for large flood events.A possible reason is that the river cross sections obtained from the SRTM-DEM are not accurate enough for inundation modelling.The Li DAR-RIM has an advantage for process modelling and scenario modelling under future climatic conditions.
基金funded by the ETFNB Environmental Trust Fund of New Brunswick(grant No.170099).
文摘Recent advances in hydraulic modeling create improved methodology to accurately predict the extent of floodplain map in order to assist policy makers to develop flood hazard mitigation measures and timely inform the local communities with the flood risk alerts.However,accurate prediction of the inundation map also depends on the spatial resolution of the topographic data.In this study,we developed a novel high-resolution modeling framework for Nashwaak River watershed,New Brunswick,Canada to capture significant flooding along the banks of the river for the two historic flood events and accurately map the floodplains for both the gauged and ungauged areas of the watershed.The model is based on HEC-RAS(US Army Corps of Engineers Hydrologic Engineering Center River Analysis System)hydraulic model and the topographic data were generated from high-resolution LiDAR data of~0.5 m.The model runs were driven by observed flow conditions applied at the boundary and the framework is based on different spatial resolution to determine the effect of spatial resolution on the predicted inundation.We validated the model simulated water surface elevation with the observed data and the model reproduces reasonably good skill score.Results from the numerical simulation suggest that apart from the strength of the stream velocity,design of the modeling framework plays an important role in determining the inundation depth as well as the maximum flooding extent.
基金supported by the National Natural Science Foundation of China (Grant No.50879041)the New Century Excellent Talents in University (NCET) Program of the Ministry of Education of China (Grants No. 06-0059 and 07-0814)
文摘Floods are essential for the regeneration and growth of floodplain forests in arid and semiarid regions. However, river flows, and especially flood flows, have decreased greatly with the increase of water diversion from rivers and/or reservoir regulation, resulting in severe deterioration of floodplain ecosystems. Estimation of the flood stage that will inundate the floodplain forest is necessary for the forest＇s restoration or protection. To balance water use for economic purposes and floodplain forest protection, the inundated forest width method is proposed for estimating the minimum flood stage for floodplain forests from the inundated forest width-stage curve. The minimum flood stage is defined as the breakpoint of the inundated forest width-stage curve, and is determined directly or analytically from the curve. For the analytical approach, the problem under consideration is described by a multi-objective optimization model, which can be solved by the ideal point method. Then, the flood flow at the minimum flood stage （minimum flood flow）, which is useful for flow regulation, can be calculated from the stage-discharge curve. In order to protect the forest in a river floodplain in a semiarid area in Xinjiang subject to reservoir regulation upstream, the proposed method was used to determine the minimum flood stage and flow for the forest. Field survey of hydrology, topography, and forest distribution was carried out at typical cross sections in the floodplain. Based on the survey results, minimum flood flows for six typical cross sections were estimated to be between 306 m3/s and 393 m3/s. Their maximum, 393 m3/s, was considered the minimum flood flow for the study river reach. This provides an appropriate flood flow for the protection of floodplain forest and can be used in the regulation of the upstream reservoir.
基金supported by the Croatian Hunting Federation(project name:Influence of climate change and extreme weather events on game mortality,No.U-47-15)。
文摘Floodplain forests with regular flooding regimes are the largest natural retentions areas in Croatia and are important as natural habitats for ungulates.The aim of this study was to determine the scale of mortality caused by flooding within these forests.Over a 10-year period,data on ungulate mortality(red deer,roe deer and wild boar),flood duration and flooded surface area were recorded.The study was conducted in primary(Posavske Sume—RET I)and secondary(Opeke II—RET II)retention areas within Lonjsko Polje Nature Park(Sava River region,Croatia).The longest flood period and the largest flooded surface area were recorded in RET I.Total ungulate mortality was749 individuals,with 482 individuals in RET I and 267 individuals in RET II,predominantly wild boar.Flood mortality did not differ by gender.The highest mortality of wild boar was recorded for the juvenile and yearling ageclasses.Low mortality of red and roe deer can be attributed to their body size and ecological niches.Differences in mortality between the primary and secondary retention areas corresponded to differences in flood regimes,flood column heights and micro relief structures.In both retention areas,wild boar mortality and flood duration,i.e.flooded surface area,were positively correlated.Because the growth rate of the analysed ungulate populations was higher than the recorded mortality,no long-term effect of floods is expected on species abundance in these areas.
文摘An exploratory study of the traditional homestead forest of two different religious groups (Hindu and Muslim) in one selected floodplain area of Bangladesh was conducted over a period of six months from January to June 2002. The species' (both tree and shrub) preferences, similarities, use and sources of planting materials, spacing and location of species in the homesteads of both Hindu and Muslim communities were studied. It was found thatMangifera indica as tree species andOcimum sanctum as shrub species were the best preferred species of the Hindu community.Artocarpus heterophyllus as tree species andLawsonia inermis as shrub species were found best preferred by the Muslim community. Floristic similarities between the two groups were found 86.57% in tree species and 78.48% in shrub species. Both seed and seedlings of tree and shrub species as planting materials were used by the highest percentage of both the religious communities. For tree species, homegarden was reported to be the highest source (39%) and for shrub species, nature was the highest source (40%), which was found in the Hindu community. Key words Species preferences - Species similarity - Planting materials - Hindu - Muslim - Homestead forests - Floodplain area - Bangladesh CLC number S72 Document code A Biography: Md. Danesh Miah (1971): male, Assistant Professor in the Institute of Forestry and Environmental Sciences, University of Chittagong, Chittagong 4331, Bangladesh.Responsible editor: Chai Ruihai
文摘Due to the regulation of the river Volga flow, expanding of the territories intended for construction and development of agriculture wetlands Volga-Akhtuba floodplain are being significantly transformed and are losing many of their qualities. Non-regulated loads lead to the break of natural physical and chemical characteristics of water bodies, loss of biodiversity, degradation of structure and functions of biological communities and, as a result, to decreasing of potential ecosystem services. Restoration of the lost qualities of water ecosystems is a key factor in increasing sustainability of reclaimed landscapes and creating comfortable conditions for living of locals and their economic activity. On the territory of the biosphere reserve “Nature park” “Volga-Akhtuba floodplain” a number of model sites were defined in order for research projects and practical work on restoration of degraded landscapes to be executed. The widest range of the lost ecosystem qualities is being restored during work on Lake Zapornoye. Restoration of ecosystem functions is being implemented according to the main economic activities carried out in this area. Ecosystem services of the area are specified in accordance with its functional purpose. The existing landscape and ecology conditions have been studied and estimated to see if the planned ecosystem services can be provided. The project suggests the following activities: restoration of hydro-morphological characteristics, reconstruction of habitats for biodiversity and their ecosystem services, improvement to restore and preserve recreational qualities of landscape. The project includes the monitoring the effectiveness of restoration. Monitoring program is based on indices of environmental assessment.
文摘The small-scale fishermen in the north-eastern floodplains are one of the most vulnerable communities of Bangladesh due to their limited income.This study assessed their livelihood status using a sustainable livelihood framework and employed a multiple regression model to evaluate factors influencing their earnings.Primary data were collected from fishermen’s households in Tanguar Haor and Hakaluki Haor through direct interviews.Results revealed that these households lacked human capital,had poor sanitation facilities and suffered from frequent diseases.Their income is very limited as they lack training on other socioeconomic activities to comple-ment their livelihood grounded on fishing.Hence,their financial capital was very deficient and ranked lowest among other livelihood capitals.Fishermen’s major physical assets were the boats used for group and individual fishing.These small-scale fishermen had limited involvement with local administration,and around half of them were members of various NGOs.Women of these households had low participation in fishing or other income activities.The income of the fishermen was influenced by their age,fish catch per day,training and NGO mem-bership.To increase the earnings and improve the livelihood status of small-scale fishers in the floodplain,this study suggests providing training on complementary income generating activities,improving sanitation facilities and providing additional government and non-government support.
文摘Soil minerals study is vital in terms of investigating the major soil forming compounds and to find out the fate of minor and trace elements in soils. It is also essential for the soil-plant interaction purpose. To identify soil mineral phases especially clay minerals, X-ray diffraction (XRD) has been a popular technique. The clay mineralogical information of soils in Bangladesh is limited, especially in Ganges flood plain region (Agro Ecological Zone (AEZ) 12 and 13). Therefore, to overcome this limitation, in this study, we performed XRD analysis of <2 mm fractions soil samples of AEX 12 and 13. However, identifying mineralogical phases by XRD in <2 mm fractions soils is not so straight-forward due to many practical problems. We fully matched only two mineralogical phases in all the soil samples which is quartz and potassium-Aluminum-Silicate. However, the full XRD peaks indicate that more minerals are also present, but due to heterogeneity of soils samples, it is difficult to find other minerals phases by only XRD peak of <2 mm fractions. Therefore, to find more information about mineralogical phases, we performed XRF analysis that provides the elemental composition of minerals phase as oxide. XRF analysis indicated the presence of secondary minerals like illite and chlorite. The presence of high percentage Fe oxide not only indicated the iron mineral phase (goethite and ferrihydrite) but also indicated iron rich high charge smectite minerals (beidellite). The presence of iron rich smectite minerals in the Ganges sediments reported in several previous studies. Thus, we concluded that only XRD in <2 mm fractions of soils is not adequate to identify the mineralogical phases of soil samples. Others analyses like XRF, XRD in <2 μm fractions will be necessary to locate an entire image of soil mineralogical phases.
文摘No simple solution to flood prevention is accessible. This research provides a brief summary of the hydrologic and hydraulic methodology that can be used to develop specific details that integrated the flood information tool. It permits rapid analysis of a wide variety of stream discharge data and topographic mapping to avoid the flood hazard over entire floodplain boundaries. This paper focuses on the water floodplain hazard in Wadi Asla-Jaddah-Saudi Arabia. The most common type of rainfall in the study area is that accompanied by thunderstorms, which usually fall during the winter season as well as in the spring. The primarily evaluation of this problem and the solution is contemplate. The more essential and ＂doable＂ elements of a solutions and recommendations are discussed in this research.
文摘The actual situation of the Tisza Valley traditionally used for land farming is basically determined by the consequences of the river regulation of the nineteenth century which aimed at the extension of the intensive agriculture, by the extreme water regime of alternating periods of flood showing a deteriorating trend and drought related to the climatic change; and by several environmental problems induced mainly by the land use. The objective of the article is to prove the regional advantages of a proposed technical solution to mitigate the flood risk with a special regard to the land cover. Hydrodynamic modeling results prove that the best technical solution is given by a combination of different strategies containing the inundation of deep floodplains-areas regularly covered by water before the river regulation works and, globally, by an important mitigation of flood damages, the costs of solution would be surely covered in the longterm. By means of its natural-resembling operation, the regular water cover would allow a multiple use of water, contributing to the solution of the simultaneously existing aridity problem, and, the development of the floodplain landscape management would help improve the ecological and the economical upgrading of the region.
文摘The GEF-WB Nutrient Reduction project aims to reduce the phosphorus inputs of the Black Sea from the Danube by means of different interventions. Hungary takes part of this project by enhancing the nutrient trapping capacity of the Gemenc and Beda-Karapancsa wetlands （GBK） which can be found on the premises of the Danube Drava National Park along the Danube River in Southern Hungary. Due to anthropogenic influences, less of small floods reach the oxbows of the area than some decades before which has a negative effect on the ecosystem. The objective of the study is to predict the nutrient reduction capacity of the Gemenc-B6da-Karapancsa water system and to make a proposal to increase this capacity. Although the floodplain vegetation has a huge nutrient intake capacity, this is limited by the fact that the floodplain is not always covered by the water of the river Danube. For that reason, a combination of hydrodynamic modelling, flood probability calculation and an estimation of suspended solids settling constitute the base of this study. The main course taken into account is the settling of suspended solids and the ratio of total nitrogen and total phosphorus to the mass of sediment is determined by local measurement results.
