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1.
Water Sci Technol ; 85(1): 383-397, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35050890

RESUMO

Most previous quantitative research conducted on urban creep and urban expansion has focused on small areas, short time periods, case studies with fairly uniform housing stock and demographic makeup, and the characterisation of urban creep and expansion exclusively in terms of impervious area changes without quantification of the consequential hydrological impact, i.e., increase in surface runoff volume and peak flows in a catchment. This study, using satellite imagery, catchment characteristics data, geographic information system and hydrologic modelling, presents, for the first time, a long-term analysis of urban creep and expansion. The case study is the Ouseburn catchment in Newcastle upon Tyne, a wide-ranging catchment made up of rural, suburban and urban areas, over a period of seven decades. The rate of increase of impervious surfaces is found not to be constant in time; the significant impact of this variation on the catchment's hydrologic response is quantified. This has overall caused a substantial flow volume increase in the Ouseburn over the study period, e.g. 48% for a 1 in 5 years rainfall event. The conclusions obtained are likely representative of many large towns and cities across the United Kingdom and the methodology presented can be easily replicated in other study areas.


Assuntos
Chuva , Movimentos da Água , Cidades , Hidrologia
2.
Environ Monit Assess ; 194(2): 108, 2022 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-35048218

RESUMO

Land-use changes have a significant impact on the hydrological cycle and non-point source (NPS) pollution discharge and transport. Thus, using dynamic land-use inputs in the simulation models is important. However, there is currently no clear standard for which situation the land-use data should be updated in the models. In this study, we quantified the impacts of land-use change on hydrological and NPS pollution simulation outputs, and analyzed the thresholds for land-use change level and time nodes. The results indicated that the error caused by land-use change had a linear relationship with the land-use change level. The total nitrogen (TN) output error was the most sensitive to land-use change, with a gradient of 0.73. The impact of land-use change on the model outputs was different at different temporal scales. Flow and TN had the highest output errors at a daily scale, while sediment had the highest output error at an annual scale. The threshold analysis results revealed that the land-use change thresholds for the flow, sediment, and TN simulations were 40%, 30%, and 10%, respectively. When the land-use change level exceeded the threshold, the model simulation error increased dramatically. The land-use change time node would also affect the simulation performance, especially for TN. This study initially explored the quantified standard for land-use data updates in the SWAT model. The results could be useful for improving the simulation accuracy of the SWAT model and may provide ideas for follow-up studies.


Assuntos
Hidrologia , Poluição Difusa , China , Monitoramento Ambiental , Modelos Teóricos , Nitrogênio/análise , Rios , Qualidade da Água
3.
Environ Monit Assess ; 194(2): 75, 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-35000017

RESUMO

For hydrological analysis, it is essential to have continuous and long-term precipitation data. However, the precipitation data from rain gauge stations are often insufficient and not continuous. At present, ground-based gridded data and satellite-based gridded data are often used as an alternative. However, these data sets have to be evaluated for their suitability in hydrological studies. The current study compared three different rainfall data sources with the observed station data for the Kallada River basin of Kerala, India. The ground-based gridded rainfall data from the India Meteorological Department (IMD), the high-resolution satellite product Tropical Rainfall Measuring Mission (TRMM 3B43, version 7), and the reanalysis data Modern-Era Retrospective Analysis for Research and Applications (MERRA) are used in the analysis. The correlation coefficient, normalized root mean square error, Nash-Sutcliffe efficiency, modified index of agreement, and volumetric efficiency are used as performance indicators. The performance indicator's weights are based on the entropy method. The multi-criteria decision-making techniques like compromise programming and Preference Ranking Organization Method (PROMETHEE II) are used for ranking the precipitation data sources. It is found that IMD ground-based gridded data is ranked 1 among the three data sets. The IMD ground-based gridded data are not homogeneous based on the absolute homogeneity test, even though they had the highest rank. The IMD gridded data are further corrected based on double mass curve analysis. The corrected data were analyzed using the precipitation concentration index (PCI) to assess the temporal variation in precipitation, and it was found that the location falls under a uniform distribution zone.


Assuntos
Monitoramento Ambiental , Hidrologia , Armazenamento e Recuperação da Informação , Chuva , Estudos Retrospectivos
4.
Sci Total Environ ; 802: 149962, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34781586

RESUMO

Drainage outflow from artificial subsurface drains can be a significant contributor to watershed water yield in many humid regions of the world. Although many studies have undertaken to simulate hydrologic processes in drained watersheds, there is a need for a study that first, uses physically based spatially distributed modeling for both surface and subsurface processes; and second, quantifies the effect of surface and subsurface parameters on watershed drainage outflow. This study presents a modified version of the SWAT+ watershed model to address these objectives. The SWAT+ model includes the gwflow module, a new spatially distributed groundwater routine for calculating groundwater storage, groundwater head, and groundwater fluxes throughout the watershed using a grid cell approach, modified in this study to simulate the removal of groundwater by subsurface drains. The modeling approach is applied to the South Fork Watershed (583 km2), located in Iowa, USA, where most fields are drained artificially. The model is tested against measured streamflow, groundwater head at monitoring wells, and drainage outflow from a monitored subbasin. Sensitivity analysis is then applied to determine the land surface, subsurface, and drainage parameters that control subsurface drainage. Simulated drainage flow fractions (fraction of streamflow that originates from subsurface drainage) range from 0.37 to 0.54 during 2001-2012, with lower fractions occurring during years of high rainfall due to the increased volumes of surface runoff. Subsurface drainage comprises the vast majority of baseflow. Results indicate surface runoff and soil percolation parameters have the strongest effect on watershed-wide subsurface drainage rather than aquifer and drain properties, pointing to a holistic watershed approach to manage subsurface drainage. The modeling code presented herein can be used to simulate significant hydrologic fluxes in artificially drained watersheds worldwide.


Assuntos
Água Subterrânea , Água , Hidrologia , Solo , Movimentos da Água
5.
Sci Total Environ ; 805: 150404, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34818793

RESUMO

The frequent urbanization and extreme rainfall events have posed the threat to the urban environment. The implementation of low impact development (LID) practices with great potential for control urban flood and overflow pollution is not comprehensively understood yet due to the influence of complex factors (i.e., hydrological pattern, installation location, and vertical parameter setting). In this study, the hydraulic and water quality model were used to analyze the hydrological and pollution reduction of outfall and storage under different hydrological patterns, vertical parameter setting, and green infrastructure installation locations, which can determine the best implementation of the scheme for overflow pollution control. The results showed that nine parameters of the vertical layer regarding the four parameters impacted the peak value and load of suspended solids (SS). The combination scheme of the LID practices was further proposed based on the selection and analysis of the single LID practice. Besides, considering the installation location, the downstream installed location was a better choice. The horizontal connection of overflow runoff and pollution could be reduced by up to 9.75% and 36.46%, respectively. In addition, the horizontal connection can effectively reduce the peak value of inflow and pollutants at the time of assessing storage tank impact, which reach the maximum of 14.08% and 29.25%, respectively. The pollutants distribution became uniform and showed better resilience against rainfall intensity, which is beneficial to the management of stormwater. Our findings can provide guidance for Sponge City construction and effectively alleviate the combined sewer overflow.


Assuntos
Chuva , Movimentos da Água , Cidades , Hidrologia , Urbanização
6.
Sci Total Environ ; 805: 150291, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34818819

RESUMO

A high biodiversity conservation value of a specific area generally indicates biodiversity priorities, making biodiversity conservation planning more reasonable. However, the spatial prioritization of biodiversity cannot easily indicate temporal changes because the data of many species are difficult to obtain in even a single period, let alone repeated surveys. Here, we show that the easily available wetland hydrological pattern and connectivity (HCP) variables are effective surrogates for the monitoring of biodiversity conservation value. We used the Systematic Conservation Planning (SCP) method to evaluate the historical biodiversity conservation value (BCV), represented by Irreplaceability Index, by integrating the predicted spatial distribution of biodiversity features in 1995. We then calculated the wetland HPC indexes in randomly setup samples within a certain radius and analysed the correlation between the BCV and HPC indexes with a regression method. Finally, we further simulated the numerical and spatial changes of the BCV in different periods to illustrate its variation regularity. We found that the BCV considerably decreased in the study area. In conclusion, we confirmed that the wetland HPC indexes are significantly correlated with and can simulate the BCV indicator. We further identified the spatial locations of these degraded areas and proposed conservation and restoration scenarios for the study area. This study verified the impacts of HPC changes on wetland biodiversity caused by human-induced land use change; it also provides a reference for long-term assessment of wetland biodiversity change. SIGNIFICANCE STATEMENT: Among other abilities, effective biodiversity conservation should have the abilities to both prioritize the conservation value and detect its spatial changes. However, the assessment of biodiversity conservation value needs sufficient and high-quality species occurrence data and multi-period comparison. Here, we find that the relatively well accessible wetland hydrological pattern and connectivity indexes are effective surrogates for the change detection of wetland biodiversity conservation value. This means that wetland biodiversity conservation planners can monitor the biodiversity conservation situations without resource-consuming investigations to obtain species' occurrence data and repeated prioritization of the conservation value.


Assuntos
Conservação dos Recursos Naturais , Áreas Alagadas , Biodiversidade , China , Ecossistema , Humanos , Hidrologia
7.
Philos Trans A Math Phys Eng Sci ; 380(2215): 20210022, 2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-34865532

RESUMO

Permafrost thaw increases active layer thickness, changes landscape hydrology and influences vegetation species composition. These changes alter belowground microbial and geochemical processes, affecting production, consumption and net emission rates of climate forcing trace gases. Net carbon dioxide (CO2) and methane (CH4) fluxes determine the radiative forcing contribution from these climate-sensitive ecosystems. Permafrost peatlands may be a mosaic of dry frozen hummocks, semi-thawed or perched sphagnum dominated areas, wet permafrost-free sedge dominated sites and open water ponds. We revisited estimates of climate forcing made for 1970 and 2000 for Stordalen Mire in northern Sweden and found the trend of increasing forcing continued into 2014. The Mire continued to transition from dry permafrost to sedge and open water areas, increasing by 100% and 35%, respectively, over the 45-year period, causing the net radiative forcing of Stordalen Mire to shift from negative to positive. This trend is driven by transitioning vegetation community composition, improved estimates of annual CO2 and CH4 exchange and a 22% increase in the IPCC's 100-year global warming potential (GWP_100) value for CH4. These results indicate that discontinuous permafrost ecosystems, while still remaining a net overall sink of C, can become a positive feedback to climate change on decadal timescales. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.


Assuntos
Pergelissolo , Dióxido de Carbono , Ecossistema , Hidrologia , Metano
8.
Sci Total Environ ; 804: 150112, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520909

RESUMO

High-elevation grasslands worldwide provide essential hydrological services including water provision, flow regulation, and erosion control. Despite their importance, hydrological research of grasslands in montane regions is usually scarce and disperse, limiting the capacity to improve water resource management. We present a systematic literature review of the hydrological function of high Andean grasslands under conserved, degraded, and restored conditions in ecosystems situated above the tree line in the tropical Andes (páramos, punas, and jalcas). Most hydrological research on these grasslands has been developed in páramos (92%), especially in Ecuador, while research in punas is scarce (6%) despite being the largest grassland extent in the region. For páramos, published literature highlights the importance of conserving grasslands to facilitate water infiltration to soils, which in turn reduces erosive processes. Water-vegetation relations for conserved páramos are well understood, indicating that about 50% of water inputs return to the atmosphere via evapotranspiration, but knowledge about hydrological functions of conserved punas and jalcas is virtually non-existent. Under changing land use, afforestation of grassland ecosystems with exotic tree species, especially pines, reduces soil water storage as well as water yield and flow regulation capacity. Impacts of grazing and agriculture on the hydrological function of páramo grasslands strongly depend on historical land management and current land use practices and are not generalizable. Short-term restoration studies indicate that more than two years are necessary to recover the hydrological function of degraded grasslands, therefore medium and long-term studies are required to determine efficient restoration periods. These knowledge gaps limit the ability to extrapolate and regionalize findings. Future directions aimed to fill them are proposed, and methods successfully used to investigate the hydrology of high Andean grasslands are highlighted. This research not only enlightens what is known about the hydrology of high Andean grasslands, but also seeks to guide future hydrological evaluations to fill identified geographical and topical knowledge gaps precluding improved management of water resources in the tropical Andes.


Assuntos
Ecossistema , Hidrologia , Agricultura , Pradaria , Solo
9.
Sci Total Environ ; 802: 149886, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525683

RESUMO

Hydropower dam constructions and operations have dramatically changed the original hydrological regime of natural rivers. Because of significantly slashed and suspended sediments blocked by damming, discharged "clear" water was found to play a strong undercutting effect on the riverbank and to exacerbate riparian soil erosion on the downstream near dams. Yet, it is still an unsettled issue whether the instability of riparian soil structure would be simply correlated negatively with the distance to a dam. In this study, soils along the downstream riparian zone of a huge dam on the River Yangtze, China, were sampled to examine the distance effect on the riparian soil structural stability. Water-stable aggregates were fractionated by the wet-sieving method. Mean weight diameter (MWD) and geometric mean diameter (GMD) were used to indicate riparian soil stability. Further, the fractal dimension (D) and soil erodibility parameter (K) were used to represent the likelihood of riparian erosion. Our results revealed that riparian soil structural stability demonstrated a high spatial heterogeneity along the River Yangtze, and was less affected by the spatial distance to the dam. Rather, the soil stability was primarily influenced by a river shape index (sinuosity) and local edaphic properties. The river sinuosity index demonstrated a positive relationship with soil structural stability. Additionally, soil organic matter was found as a major edaphic factor in stabilizing soil structure. The results indicated that river sinuosity plays a crucial role in stabilizing soil by accumulating soil organic matters. Our findings implied that the potential negative impact of damming effect on soil stability may be attenuated by maintaining a higher sinuosity of the river. Against the risk of riparian soil erosion along the dammed river, the configuration of river morphology shall be considered as one of the potential managements in offsetting the negative impacts of damming.


Assuntos
Rios , Solo , China , Hidrologia
10.
Sci Total Environ ; 802: 149903, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525695

RESUMO

Large-scale invasion modifies watershed hydrology by changing surface runoff and lowering the seasonal availability of water to native plants. Due to costly field-based evapotranspiration (ET) measurements, which are highly localized and occasionally subject to instrument failure, landscape-scale water use assessments of invasive plants are infrequent. Therefore, the extent to which plant invaders alter water allocation between native and non-native vegetation in a given landscape is rarely assessed. We used a remote sensing-based ET modeling approach to measure the hydrologic response of an invasive shrub, Ligustrum sinense, across forests of the Charlotte Metropolitan Area, North Carolina. We hypothesized that this invader's widespread occurrence and dominant plant physiology significantly competes with native forests for water resources. We tested this hypothesis by comparing inter- and intra-annual variations in ET from invaded and uninvaded sites estimated using the surface-energy-balance system (SEBS) model and cloud-free Landsat images for the wettest (2003), driest (2007), and normal (2005 and 2011) water years. Our findings suggest that the water demand of L. sinense is higher than native forests (deciduous and evergreen) for most of the year except during the early spring and after high precipitation events. The daily ET flux of L. sinense was significantly different than evergreen vegetation during the driest year (2007) that, five years later (2011 - normal water year), was significantly different than both deciduous and evergreen vegetation types. This suggests that L. sinense consumes more water than native forest types, particularly during dry and normal precipitation years with increasing canopy cover over time making it a strong competitor with native vegetation for water resources in urban forests. Therefore, accounting for the hydrologic response of invasive plants and potential water savings from their removal from forests, particularly in water-scarce regions, may enable land managers and decision-makers to prioritize areas for monitoring and control efforts.


Assuntos
Florestas , Hidrologia , Plantas , Estações do Ano , Recursos Hídricos
11.
Sci Total Environ ; 803: 149894, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525756

RESUMO

With the growing demand of assessing the ecological status, there is the need to fully understand the relationship between the planktic diversity and the environmental factors. Species richness and Shannon index have been widely used to describe the biodiversity of a community. Besides, we introduced the first ordination value from non-metric multidimensional scaling (NMDS) as a new index to represent the community similarity variance. In this study, we hypothesized that the variation of diatom community in rivers in an agricultural area was influenced by hydro-chemical variables. We collected daily mixed water samples using ISCO auto water samplers for diatoms and for water-chemistry analysis at the outlet of a lowland river for a consecutive year. An integrated modeling was adopted including random forest (RF) to decide the importance of the environmental factors influencing diatoms, generalized linear models (GLMs) combined with 10-folder cross validation to analyze and predict the diatom variation. The hierarchical analysis highlighted antecedent precipitation index (API) as the controlling hydrological variable while water temperature, Si2+ and PO4-P as the main chemical controlling factors in our study area. The generalized linear models performed better prediction for Shannon index (R2 = 0.44) and NMDS (R2 = 0.51) than diatom abundance (R2 = 0.25) and species richness (R2 = 0.25). Our findings confirmed that Shannon index and the NMDS as an index showed good performance in explaining the relationship between stream biota and its environmental factors and in predicting the diatom community development based on the hydro-chemical predictors. Our study showed and highlighted the important hydro-chemical factors in the agricultural rivers, which could contribute to the further understanding of predicting diatom community development and could be implemented in the future water management protocol.


Assuntos
Diatomáceas , Biodiversidade , Monitoramento Ambiental , Hidrologia , Rios
12.
Sci Total Environ ; 805: 150257, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34536870

RESUMO

Drought incidents and the pressure on water resources have increased in recent years, which has threatened sustainable development. Recently, research has been conducted on drought propagation. However, few studies have investigated the characteristics and mechanisms of drought propagation in plateau mountainous regions with complex topography, which limits the efforts to mitigate drought. We used the Longchuan River Basin (LRB) in Southwest China as a case study to analyze the spatiotemporal variations of meteorological, hydrological, and agricultural droughts and the process of drought propagation in plateau mountainous regions. Our results demonstrated that: (1) the variation in the intensity, frequency, and coverage of droughts indicated that meteorological droughts and hydrological droughts were increasingly serious, while agricultural droughts were eased from 2000 to 2015; (2) the propagation time between different types of droughts was approximately 2 months; and (3) the propagation sequences of droughts varied by altitude; in particular, agricultural droughts propagated to hydrological droughts at higher altitudes, and the opposite occurred at lower altitudes. We concluded that elevation plays a critical role in the time-space differentiation of drought propagation in plateau mountains. More attention should be paid to the spatial differentiation of drought propagation based on land use under different topographic conditions. The results of this study can provide a new perspective for future drought propagation studies.


Assuntos
Secas , Hidrologia , China , Meteorologia , Rios
13.
Sci Total Environ ; 805: 150256, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34537693

RESUMO

Iron (Fe) is an important element in aquatic ecosystems worldwide because it is intimately tied with multiple abiotic and biotic phenomena. Here, we give a survey of manifold influences of Fe, and the key factors affecting it in the boreal catchments and their waters. It includes the perspectives of biogeochemistry, hydrology, ecology, and river basin management. We emphasize views on the dynamics and impacts of different forms of Fe in riverine environments, including organic colloids and particles, as well as inorganic fractions. We also provide perspectives for land use management in boreal catchments and suggest guidelines for decision making and water management. Based on our survey, the main emphases of water protection and management programs should be (i) prevention of Fe mobilization from soil layers by avoiding unnecessary land-use activities and minimizing soil disturbance in high-risk areas; (ii) disconnecting Fe-rich ground water discharge from directly reaching watercourses; and (iii) decreasing transport of Fe to watercourses by applying efficient water pollution control approaches. These approaches may require specific methods that should be given attention depending on catchment conditions in different areas. Finally, we highlight issues requiring additional research on boreal catchments. A key issue is to increase our understanding of the role of Fe in the utilization of DOM in riverine food webs, which are typically highly heterotrophic. More knowledge is needed on the metabolic and behavioral resistance mechanisms that aquatic organisms, such as algae, invertebrates, and fish, have developed to counter the harmful impacts of Fe in rivers with naturally high Fe and DOM concentrations. It is also emphasized that to fulfil the needs presented above, as well as to develop effective methods for decreasing the harmful impacts of Fe in water management, the biogeochemical processes contributing to Fe transport from catchments via rivers to estuaries should be better understood.


Assuntos
Água Subterrânea , Rios , Animais , Ecossistema , Hidrologia , Ferro
14.
Sci Total Environ ; 806(Pt 1): 150313, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34555608

RESUMO

Most research on the ecological responses to extreme floods examines impacts at short time scales, whereas long-term datasets combining hydrological and biological information remain rare. Using such data, we applied time-series analysis to investigate simultaneous effects of a biotic factor (density dependence), an abiotic factor (extreme floods), and spatial synchrony in the population dynamics of three riverine insects. Spatial synchronization of population dynamics by extreme floods varied among species. These different responses to extreme floods could be explained by species-specific biological traits. Moreover, density dependence influenced the population dynamics under the context of extreme floods. Accordingly, quasi-extinction risks were highest for species that were simultaneously influenced by biotic and abiotic factors. An understanding of ecological responses to increasing hydrological extremes may be enhanced by recognizing long-term, climatic non-stationarity.


Assuntos
Inundações , Rios , Extinção Biológica , Hidrologia , Dinâmica Populacional
15.
J Environ Manage ; 301: 113750, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34597953

RESUMO

Conventional green roofs have often been criticised for their limited water buffer capacity during extreme rainfall events and for their susceptibility to droughts when additional irrigation is unavailable. One solution to these challenges is to create an extra blue water retention layer underneath the green layer. Blue-green roofs allow more stormwater to be stored, and the reservoir can act as a water source for the green layer throughout capillary rises. An automated valve regulates the water level of the system. It can be opened to drain water when extreme precipitation is expected. Therefore, the water buffer capacity of the system during extreme rainfall events can be maximised by integrating precipitation forecasts as triggers for the operation of the valve. However, the added value of this forecast-based operation is yet unknown. Accordingly, in this study, we design and evaluate a hydrological blue-green roof model that utilises precipitation forecasts. We test its performance to capture (extreme) precipitation and to increase evapotranspiration and evaporative cooling under a variety of precipitation forecast-based decision rules. We show that blue-green roofs can capture between 70 % and 97 % of extreme precipitation (>20 mm/h) when set to anticipate ensemble precipitation forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF). This capture ratio is considerably higher than that of a conventional green roof without extra water retention (12 %) or that of a blue-green roof that does not use forecast information (i.e., valve always closed; 59 %). Moreover, blue-green roofs allow for high evapotranspiration rates relative to potential evapotranspiration on hot summer days (around 70 %), which is higher than from conventional green roofs (30 %). This serves to underscore the higher capacity of blue-green roofs to reduce heat stress. Using the city of Amsterdam as a case study, we show the high upscaling potential of the concept: on average, potentially suitable flat roofs cover 13.3 % of the total area of the catchments that are susceptible to pluvial flood risk. If the 90th percentile of the ECMWF forecast is used, an 84 % rainfall capture ratio can translate into capturing 11 % of rainfall in flood-prone urban catchments in Amsterdam.


Assuntos
Chuva , Movimentos da Água , Cidades , Conservação dos Recursos Naturais , Hidrologia
16.
Environ Pollut ; 292(Pt A): 118313, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34634400

RESUMO

Herein, a two-dimensional (2-D) vertically-averaged hydrodynamic model was applied to study the heavy metal particle footprints pre- and post-Three Gorges Dam (TGD) in Poyang Lake. Two defined indexes-Reserve Impact Index (σRII) and Species Impact Index (ηSII) were applied to assess the potential impact of the copper footprint on nature reserves and sensitive species quantitatively. The results demonstrated that the movement speed, distribution, and trajectory of copper particle footprints differed enormously pre- and post-TGD. By contrast, the post-TGD footprints were more complex because of the dam-induced variations in hydrology and meteorology. TGD had both pros and cons for the copper footprint on the reserves based on the results of σRII. It had changed the way for the transport of heavy metals and altered the patterns of exposure risk in the reserves. Sustainable management of Poyang Lake could be achieved by optimizing daily monitoring works. The ηSII for Finless Porpoises do not differ significantly between scenarios, but the ηSII for Siberian White Cranes increased by 0.92 and 0.83 for the two periods pre- and post-TGD, respectively. Heavy metals in food sources and the excreta of Siberian White Cranes could be of great concern in future studies. This study provides a theoretical basis for the in-depth study of the TGD-induced impact on Poyang Lake and provides a reference for the long-term treatment of Poyang Lake and the protection of key species.


Assuntos
Lagos , Metais Pesados , Animais , Aves , China , Monitoramento Ambiental , Hidrologia , Metais Pesados/análise
17.
Sci Total Environ ; 802: 149713, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34454136

RESUMO

Using the parameters associated with the best-fit simulation (i.e., the simulation with the highest objective function value) to represent a calibrated hydrological model is inadequate. The reason is that the calibrated models best objective function value is usually not significantly different from the next best value or the values after that. This non-uniqueness of the objective function values causes a problem because the best solution's parameters are often significantly different from the next best set of parameters. Therefore, only using the best simulation parameters as the calibrated model's sole parameters to interpret the watershed processes or perform further modeling analyses could produce misleading results. Furthermore, the lack of pristine watersheds makes the task of watershed-scale calibration increasingly challenging. Subjective thresholds of acceptable performance criteria suggested by some researchers, based on comparing the measured and the best solution signals, are often not achievable. Hence, to obtain a satisfactory fit, researchers and practitioners are often forced to compromise the science behind their work. This article discusses the fallacy in using the best-fit solution in hydrologic modeling. A two-factor statistic to assess the goodness of calibration/validation is discussed, considering model output uncertainty.


Assuntos
Hidrologia , Modelos Teóricos , Calibragem , Simulação por Computador , Incerteza
18.
Sci Total Environ ; 802: 149831, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34454152

RESUMO

Quantifying the climatic and anthropogenic effects on hydrological processes has received considerable attention. However, diverse conclusions could be drawn when different models and forcing datasets are used. This is particularly uncertain and challenging in poorly gauged arid regions. Here we aim to tackle this issue in the poorly gauged Xiangride River Basin within the Qaidam Basin, one of the three prominent inland basins in China. We applied two distinct models (Budyko Mezentsev-Choudhurdy-Yang and process-based SWAT) to a poorly-gauged inland basin in West China. The model simulations were driven by four precipitation products including Tropical Rainfall Measuring Mission (TRMM) 3B42 V7, Global Precipitation Measurement (GPM) IMERG V6, Multi-Source Weighted-Ensemble Precipitation (MSWEP) and China Meteorological Assimilation Driving Datasets (CMADS). Our results indicate that MSWEP performed best (NSE = 0.64 vs. 0.36-0.59 for other datasets) in the baseline period (2009-2012), whereas CMADS was more accurate during the impacted period (2013-2016); CMADS and GPM might underestimate the precipitation in the baseline and impacted period, respectively. Hydrological processes during the impacted period are presumed to be influenced by climate variation and/or human activities, compared to the relatively natural status in the baseline period. We conclude that runoff decline between the two periods was mainly affected by human activities (-66 to 94%), whereas the contribution of climate variation was more likely positive. A literature survey reveals that major anthropogenic effects in the study area includes reservoir, road construction and cropland expansion that could lead to runoff decrease. We recommend the use of process-based model (e.g., SWAT) in studies like this, as process-based models driven by high-quality remote-sensed or reanalysis climate datasets, better represents the spatiotemporal hydrological change under altered conditions, whereas the steady-state assumption of soil water for the Budyko model may not be fully satisfied during a short period.


Assuntos
Hidrologia , Rios , China , Atividades Humanas , Humanos , Movimentos da Água
19.
Sci Total Environ ; 802: 149872, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34461480

RESUMO

In many high altitude river basins, the hydro-climatic regimes and the spatial and temporal distribution of precipitation are little known, complicating efforts to quantify current and future water availability. Scarce, or non-existent, gauged observations at high altitudes coupled with complex weather systems and orographic effects further prevent a realistic and comprehensive assessment of precipitation. Quantifying the contribution from seasonal snow and glacier melt to the river runoff for a high altitude, melt dependent region is especially difficult. Global scale precipitation products, in combination with precipitation-runoff modelling may provide insights to the hydro-climatic regimes for such data scarce regions. In this study two global precipitation products; the high resolution (0.1°â€¯× 0.1°), newly developed ERA5-Land, and a coarser resolution (0.55°â€¯× 0.55°) JRA-55, are used to simulate snow/glacier melts and runoff for the Gilgit Basin, a sub-basin of the Indus. A hydrological precipitation-runoff model, the Distance Distribution Dynamics (DDD), requires minimum input data and was developed for snow dominated catchments. The mean of total annual precipitation from 1995 to 2010 data was estimated at 888 mm and 951 mm by ERA5-Land and JRA-55, respectively. The daily runoff simulation obtained a Kling Gupta efficiency (KGE) of 0.78 and 0.72 with ERA5-Land and JRA-55 based simulations, respectively. The simulated snow cover area (SCA) was validated using MODIS SCA and the results are quite promising on daily, monthly and annual scales. Our result showed an overall contribution to the river flow as about 26% from rainfall, 37-38% from snow melt, 31% from glacier melt and 5% from soil moisture. These melt simulations are in good agreement with the overall hydro-climatic regimes and seasonality of the area. The proxy energy balance approach in the DDD model, used to estimate snow melt and evapotranspiration, showed robust behaviour and potential for being employed in data poor basins.


Assuntos
Monitoramento Ambiental , Neve , Hidrologia , Camada de Gelo , Rios
20.
Sci Total Environ ; 806(Pt 1): 150443, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34844310

RESUMO

Understanding the suitability of Satellite Rainfall Estimates (SREs) in simulating high flows and Actual Evapotranspiration (AET) is crucial for developing flood monitoring systems. Therefore, this study aims to assess i) the suitability of SREs in simulating both high flows and AET for different levels of model complexity, and ii) the effect of streamflow calibration on simulating AET for different rainfall inputs in Melkakunitre catchment, Upper Awash Basin, Ethiopia. Three state-of-the-art SREs (TRMM 3B42v7, IMERG v06B, and TAMSAT v3) were used and their usefulness in simulating high flows (Q5), daily streamflow, and wet season flows (from June to September) was assessed using the HBV-light model for the period 2003-2015. The model was set up for two levels of complexity: with and without considering the effect of orography on rainfall and temperature. Moreover, the water balance derived AET was compared against three remotely sensed AET products, MOD 16A2, GLEAM v3, and SSEBob, so as to examine the effect of streamflow calibration on AET simulation. Results show that rainfall inputs and model complexity have a strong impact on simulating streamflow and AET. For all rainfall forcing datasets, the performance of the hydrological model improves when we consider the effects of orography on rainfall and temperature. The IMERG v06B and TAMSAT v3 products showed the highest and least performances in simulating all the three flow conditions, respectively. Moreover, the MODIS-AET is the best remotely sensed AET product in reproducing the water balance-derived AET for all rainfall inputs except TAMSAT v3. The HBV-light model parameters calibrated with streamflow provided better results for simulating AET as well. On average, the usefulness of the IMERG v06B product for simulating high flows and AET is outstanding and can be thus used for developing flood monitoring and management systems in the study catchment.


Assuntos
Inundações , Hidrologia , Etiópia , Temperatura
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