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Journal of Hydrology
Elsevier
Journal of Hydrology

Elsevier

0022-1694

Journal of Hydrology/Journal Journal of HydrologySCIISTPEIAHCI
正式出版
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    Short-term flood probability density forecasting using a conceptual hydrological model with machine learning techniques

    Zhou, YanlaiCui, ZhenLin, KanglingSheng, Sheng...
    13页
    查看更多>>摘要：Making accurate and reliable probability density forecasts of flood processes is fundamentally challenging for machine learning techniques, especially when prediction targets are outside the range of training data. Conceptual hydrological models can reduce rainfall-runoff modelling errors with efficient quasi-physical mechanisms. The Monotone Composite Quantile Regression Neural Network (MCQRNN) is used for the first time to make probability density forecasts of flood processes and serves as a benchmark model, whereas it confronts the drawbacks of overfitting and biased-prediction. Here we propose an integrated model (i.e. XAJ-MCQRNN) that incorporates Xinanjiang conceptual model (XAJ) and MCQRNN to overcome the phenomena of error propagation and accumulation encountered in multi-step-ahead flood probability density forecasts. We consider flood forecasts as a function of rainfall factors and runoff data. The models are evaluated by long-term (2009-2015) 3-hour streamflow series of the Jianxi River catchment in China and rainfall products of the European Centre for Medium-Range Weather Forecasts. Results demonstrated that the proposed XAJ-MCQRNN model can not only outperform the MCQRNN model but also prominently enhance the accuracy and reliability of multi-step-ahead probability density forecasts of flood process. Regarding short-term forecasts in testing stages at four horizons, the XAJ-MCQRNN model achieved higher Nash-Sutcliffe Efficiency but lower Root Mean Square Error values, while improving Coverage Ratio and Relative Bandwidth values in comparison to the MCQRNN model. Consequently, the improvement can benefit the mitigation of the impacts associated with uncertainties of extreme flood and rainfall events as well as promote the accuracy and reliability of flood forecasting and early warning.
      原文链接:
    • NSTL
    • Elsevier

    Monitoring global reservoirs using ICESat-2: Assessment on spatial coverage and application potential

    Song, ChunqiaoLuo, ShuangxiaoKe, LinghongLiu, Kai...
    12页
    查看更多>>摘要：Satellite remote sensing is essential for monitoring surface water dynamics on Earth. Space-borne altimeter observations have become an important data source to supplement in-situ measurements of water levels. The applications of satellite radar altimetry in monitoring reservoirs at global or regional scales have been well demonstrated in many previous studies. However, studies on medium- and small-sized reservoirs are limited due to the coarser footprints and relatively low vertical accuracy. In anticipation of new satellite laser altimetry missions, we aim to demonstrate the coverage performance of ICESat-2 for global reservoirs and to further explore its application potential in monitoring the long-term changes in water level and storage of reservoirs by integrating Landsat 8 and Sentinel-2 imagery datasets. In the first 18 months of the ICESat-2 mission, we find that ICESat-2 observations can cover 6231 out of 7250 reservoirs worldwide inventoried in the GRanD database with a size ranging from 0.1 km(2) to 67166.2 km(2), which accounts for nearly 86% in count and about 99% in area and capacity for the whole of GRanD-inventoried reservoir. We then select 40 reservoirs of different sizes and shapes located in different continents to establish the hypsometric curves. Most of these reservoirs show robust fitting in the hypsometric curves, with the R-2 values ranging from 0.60 to 0.99 and the RMSE values from 0.37 m to 1.01 m. As a new global satellite altimetry dataset, ICESat-2 shows excellent potential in reconstructing long-term water levels with the hypsometric curve method for various reservoirs. We also find that the ICESat-2 ATL13 product misses a small proportion of reservoirs for various reasons, including their small size, latitudinal narrow shape, and data inconsistency between the HydroLAKES as water mask of the ICESat-2 ATL13 product and the updated GRanD data sets. With the continued observation of ICESat-2 and possibly updated inland water body mask for the ATL13 product in the future, many reservoirs can be routinely monitored with high accuracy. Our findings confirm the powerful capacity of ICESat-2 and are expected to enhance our understanding of reservoir behavior in global hydrological processes and water resource management.
      原文链接:
    • NSTL
    • Elsevier

    Overtopping and flood routing process of landslide dams consisted of ice-soil mixtures: A preliminary study

    Chen, ChenLi, HuanyunChen, JiankangZhang, Jianmin...
    15页
    查看更多>>摘要：With global warming, glacial collapse chain disasters have frequently occurred in high-mountain areas. In particular, the ice avalanche-glacial debris flow/landslide-barrier lake-flood burst chain disaster caused the most serious consequences. Different from the general landslide dam consisted of rocks and soils, the landslide dam initiated by ice avalanches contains a considerable amount of ice. The appearance of ice will influence the overall performance of the landslide dam by melting, which may cause differential settlements, local weak zones, a more porous structure, and a lower erosion resistance of the landslide dam. Such changes in the erodibility and geometry of the landslide dam will further affect the dam overtopping and flood routing process, which have not been investigated yet and urgently require further study. Therefore, in this study, a preliminary study of the effects of different ice fractions of the landslide dam is conducted, which mainly involves changes in the dam erodibility, the dam geometry, the overtopping development, the final breach size, the process of downstream flood routing, etc. Results show that with the increasing amount of ice melting, the coefficient of soil erodibility and the soil void ratio increase significantly, implying a more erodible dam material and a looser dam structure. The melting of ice can also induce obvious dam settlement, which further results in an earlier dam burst and a shorter rescue time. With the increasing initial ice amount in the landslide dam, the overtopping process develops more rapidly, the breach expands greater both horizontally and vertically, the subsequent flood becomes larger, and the peak arrival time comes earlier.
      原文链接:
    • NSTL
    • Elsevier

    Modeling lake bathymetry and water storage from DEM data constrained by limited underwater surveys

    Liu, KaiSong, Chunqiao
    12页
    查看更多>>摘要：Lake bathymetry, which provides crucial information for water resource management, has been widely used in hydrological, ecological, and geomorphological studies. Restricted by the high cost of conventional full-covered lake field surveys and the large uncertainty of spatial prediction method that models lake underwater depths from the surrounding exposed terrains, the knowledge on lake bathymetry worldwide is scarce and inconsistent. This study aims to solve the problem by investigating how the optimized spatial prediction methods are developed by combining limited field survey data. Two methods, namely, the skeleton-based interpolation method that extends the exposed topography toward the lake underwater area with a constraint of field surveys, and the machine learning method (XGBoost) that establishes the decision rule between measured water depths and multiple geospatial variables to predict depths of unknown underwater areas, were developed and tested in twelve representative lakes in the Tibetan Plateau. Our results suggest that both methods can provide acceptable estimations of underwater topography by comparing with measured data, with the mean R2 of 0.70 approximately. The overall performance of the machine learning method (XGBoost) is more reliable, with the biases less than 20% in water volume estimates for all lake cases. In comparison, the skeleton-based interpolation method outperforms lakes in long and narrow shapes. This study is expected to provide an efficient approach for modeling lake bathymetry and to improve the monitoring capacity of freshwater mass changes, especially for ungauged lakes in harsh environments.
      原文链接:
    • NSTL
    • Elsevier

    Factor affecting nitrate in a mixed land-use watershed of southern China based on dual nitrate isotopes, sources or transformations?

    Xuan, YingxueLiu, GuangliZhang, YizhangCao, Yingjie...
    15页
    查看更多>>摘要：River nitrate (NO3-) pollution is ubiquitous and has attracted worldwide attention. The continuous increase nitrate flux in the river system is mainly caused by inputs of exogenous nitrate sources or nitrogen transformations. In this study, coupled nitrogen and oxygen isotopes of nitrate were used to identify sources and transformations of nitrate in a mixed land use watershed of southern China (the Beijiang River basin), aimed at evaluating the impacts of sources or transformations on nitrate pollution and provide guidance for aquatic environment management. The results showed that the NO3--N flux in the Beijiang River Basin was 9.37 x 104 tons in 2015; isotopic evidence indicated that the impacts of nitrogen transformations in the river on the removal and production of nitrate were not significant, and the increased NO3--N concentration along the river was caused by inputs of exogenous nitrate sources. The isotope-based source apportionment revealed that approximately 52% of the influx NO3--N was contributed by synthetic fertilizer, 27% by soil nitrogen and 21% by domestic sewage. There was no significant temporal variations in source apportionment; however, significant spatial variations were found across the study area. The spatial variations were mainly affected by the different land use patterns. With the increasing percentage of urbanized areas, the proportional contributions of domestic sewage have increased, which has resulted in an increased NO3--N concentration. In addition, the relationships between the land use index and proportional contributions of different nitrate sources suggested that the effect of urbanized area might be more pronounced on nitrate pollution in a mixed land use watershed. Therefore, the results of this study suggested that land use should be considered in nitrate pollution management strategies and reducing inputs of nitrate sources to river water is crucial to reducing nitrate pollution in mixed land use watersheds.
      原文链接:
    • NSTL
    • Elsevier

    Intercomparison of joint bias correction methods for precipitation and flow from a hydrological perspective

    Kim, Kue BumKwon, Hyun-HanHan, Dawei
    16页
    查看更多>>摘要：The typical framework of the climate change impact assessment on water resources relies on plausible scenarios obtained from global climate models (GCMs) and hydrological models (HMs). Although regional climate models (RCMs) can better simulate local climate at a high-resolution grid, the direct use of model outputs from RCMs is not recommended as inputs for HMs due to systematic error. Existing studies have focused on the bias correction (BC) of climate model outputs without considering uncertainties/biases in hydrological modeling. In this regard, this study proposed an integrated framework that combines the BC of RCM precipitation and the simulated flow from the rainfall-runoff model, considering the underlying uncertainty in the parameters of the distribution function. The regional climate model, HadRM3, and the conceptual rainfall-runoff model, HYMOD, are employed. Observed daily precipitation, evapotranspiration, and discharge time series over the Thorverton catchment are compiled from the UK Meteorological Office. To examine the effectiveness of the combined strategy, four different BC approaches have been explored to reduce systematic biases in the flow simulated through the HMs using the RCM precipitation as input. Here, BCs of RCM and HM outputs have been applied under the condition that the bias-corrected ensembles should be within the range of the observed climate variability. The four BC models are considered: aathe RCM precipitation and flow are corrected by preserving their natural variabilities (Case-4). From a hydrological perspective, the Case-4 model showed the best performance among the four cases in terms of correcting the bias and the spread of the flow ensemble.
      原文链接:
    • NSTL
    • Elsevier

    Solute dispersion in an open channel turbulent flow: Solution by a generalized model

    Guo, JinlanJiang, WeiquanChen, GuoqianLi, Zhi...
    14页
    查看更多>>摘要：In this work, the classic problem in environmental hydraulics of solute dispersion in an open channel turbulent flow is analytically investigated by Gill's generalized dispersion model to account for all the basic characteristics as dispersivity, skewness and kurtosis of the mean concentration evolution. A complete solution is presented for the whole process and three typical time-scales are determined: after a convection-dominated initial stage, a transient stage with essential transverse diffusion effect begins at a dimensionless time-scale of t similar to 0.1 and gives way to an asymptotic stage of normal distribution of mean concentration from t similar to 1, slowly approaching to a final stage with relative uniformity in transverse concentration distribution at t similar to 10. Two-dimensional concentration distribution shows that there is a high concentration zone near the free water surface at a small time due to the small velocity gradient, indicating that it is not enough to characterize the dispersion process by the mean concentration, especially for the transient stage. The obtained analytical solutions of concentration distribution consist well with numerical simulation results by the random displacement method (RDM).
      原文链接:
    • NSTL
    • Elsevier

    Event-based analysis of wetland hydrologic response in the Prairie Pothole Region

    Ali, GenevieveBadiou, PascalHaque, Aminul
    17页
    查看更多>>摘要：Previous studies in the Prairie Pothole Region mainly assessed wetland hydrologic function at seasonal, annual and decadal scales. While many studies have looked at water balance dynamics and local flow generation processes in wetlands, no study looked at hydrological dynamics in response to individual rainfall events in prairie pothole wetlands (here after referred as wetlands) across a gradient of alteration. The present study aimed to investigate: (1) the most important metrics needed to characterize the spatial variability of wetland hydrologic response to rainfall-runoff events; (2) the temporal variability of individual wetland hydrologic response; (3) the spatial and temporal variability of wetland-stream interaction; and (4) the temporal persistence of various spatial controls on individual wetland hydrologic response characteristics. High-frequency water level data was collected over two years for ten intact, three consolidated, and seven drainage ditches associated with fully drained wetland(s), as well as a creek located in southwestern Manitoba, Canada. The hydrologic response of the studied wetlands to individual rainfall-runoff events was characterized using a range of metrics. Several data analysis methods were used, including principal component analysis, graphical assessments of wetland-stream hysteresis dynamics, and correlations analyses between wetland response metrics and spatial characteristics. Results suggested that wetland alteration status (i.e., drained versus intact, open-water wetlands) plays an important role in explaining differences in the event-scale hydrologic behaviour of wetlands. Climatic and antecedent storage conditions (i.e., surface and subsurface storage in wetland basin) also had a strong influence on the hydrologic responses of wetlands during individual rainfall-runoff events and appeared to override the influence of spatial controls such as wetland area, volume or catchment area. Antecedent storage also seemed to be the driving factor of wetland-stream interactions. A lack of persistent correlations between wetland spatial characteristics and response metrics was observed and suggested nonstationary wetland hydrological behaviours and controls, a conclusion that has significant implications for wetland classification and modelling.
      原文链接:
    • NSTL
    • Elsevier

    Irrigation water quality in Ghana and associated implications on vegetables and public health. A systematic review

    Amuah, Ebenezer Ebo YahansAmanin-Ennin, PrinceAntwi, Kwabena
    14页
    查看更多>>摘要：The use of contaminated water for irrigation is a major global concern. This study then reviews the impacts of irrigation water on vegetables in peri-and urban areas and the associated public health implications, and emerging contaminats in irrigation water in Ghana. Considering the quality of irrigation water, loads of enteric bacteria have been reported reaching 538 mpn/ml and 940 mpn/ml. Though total and fecal coliforms and E. coli have been detected in irrigable water in Ghana, Ascaris lumbricoides, hookworm, and Trichuris trichiura were observed in vegetables. Lambda-cyhalothrin, chlorpyrifos, diazinon, alpha-endosulfan, endrin, 1,1-dichloro-2, 2bis (4-chlorophenyl) ethylene (p,p-DDE), and hexachlorocyclohexane (HCH) are the dominant pesticides detected in water used for irrigation. The presence of Cr, Cd, Co, Cu, Zn, Pb, Fe, Ni, and Mn have been reported in irrigatable water. Contaminants of emerging concern (CEC) that require extensive research in irrigation water are antibiotics, viruses (norovirus and adenovirus), and estrogens. Since untreated wastewater is predominantly used for irrigation in some parts of Ghana, high levels of Hg and Cd have been detected. Findings from this review indicate that the safety of vegetables sold in Ghana are largely dependent on the quality of water used for irrigation.
      原文链接:
    • NSTL
    • Elsevier

    Use of convolutional neural networks with encoder-decoder structure for predicting the inverse operator in hydraulic tomography

    Jardani, A.Vu, T. M.Fischer, P.
    13页
    查看更多>>摘要：ABS T R A C T In this manuscript, we discuss the capabilities of a deep learning algorithm implemented with the Conventional Neural Network concept to characterize the hydraulic properties of aquifers. The algorithm called CNN-HT is designed to predict the inverse operator of hydraulic tomography using a synthetic training dataset in which the hydraulic head data associated with pumping tests are linked to hydraulic transmissivity field. This approach relies on an adaptation of the SegNet network that was initially developed to process image segmentation. The SegNet is composed of encoders and decoders networks. In the encoder, sequential operations with multiple filters, as convolution, batch normalization, max-pooling are performed to identify feature maps of the input data. In the decoder, the up-sampling, convolution, batch normalization and regression operations are used to prepare the output by recovering the loss of spatial resolution that occurred in the encoder process. In this adaptation, we used the least-square iterative formulation at the initial iteration with Jacobian matrix to resize the hydraulic head data to match the size of the output (transmissivity field). This protocol was applied to the hydraulic head data computed numerically by solving the groundwater flow equation for a given transmissivity field, generated geostatistically with Gaussian and spherical variograms. A part of this data was used for training the network and the other part to test its performance. The test step confirmed the effectiveness of this tool in reconstructing the main heterogeneities of the hydraulic properties, and its effectiveness is related to the nature and quantity of the training data. Moreover, the CNN-HT method provided inversion results of the same quality than those obtained with the Gauss-Newton algorithm using the finite difference or adjoint state method in the computation of the Jacobian matrix. However, the computational time is longer in CNN-HT but this time can be less or of the same order as that of Gauss-Newton using finite difference method.
      原文链接:
    • NSTL
    • Elsevier