Showing papers in "Journal of Hydrologic Engineering in 2015"
TL;DR: In the context of global environmental and social change, with increasing pollution and decline of biodiversity of terrestrial and aquatic ecosystems having its deep roots in drastic modifications to hydrological mesocycles, there is an urgent need for a new approach for sustainability.
Abstract: In the context of global environmental and social change, with increasing pollution and decline of biodiversity of terrestrial and aquatic ecosystems having its deep roots in drastic modifications to hydrological mesocycles, there is an urgent need for a new approach for sustainability. The two often contradicting approaches to water resources management, i.e., (1) hydrotechnical, and (2) ecological, can be reconciled within the context of ecohydrology (EH). It seeks for the understanding of the underlying water-biota interactions as well as providing a new tool for management of water resources. While the majority of changes are nonreversible in the framework of ecohydrology it is possible to regulate (dual regulation) the processes, especially in novel ecosystems, as an alternative to conservation and restoration measures, in order to increase their carrying capacity in the four dimensions, as follows: (1) water resources, (2) biodiversity, (3) ecosystem services, and (4) resilience. The propose...
108 citations
TL;DR: An attempt is made to analyze how this is the result of the epistemic uncertainties inherent in the hydrological modeling process and their impact on model conditioning and hypothesis testing.
Abstract: There remains a great deal of uncertainty about uncertainty estimation in hydrological modeling. Given that hydrology is still a subject limited by the available measurement techniques, it does not appear that the issue of epistemic error in hydrological data will go away for the foreseeable future, and it may be necessary to find a way to allow for robust model conditioning and more subjective treatments of potential epistemic errors in prediction. In this paper an attempt is made to analyze how this is the result of the epistemic uncertainties inherent in the hydrological modeling process and their impact on model conditioning and hypothesis testing. Some ideas are proposed about how to deal with assessing the information in hydrological data and how it might influence model conditioning based on hydrological reasoning, with an application to rainfall-runoff modeling of a catchment in northern England, where inconsistent data for some events can introduce disinformation into the model conditioning process. A methodology is presented to make an assessment of the relative information content of calibration data before running a model that can then inform the evaluation of model runs and resulting prediction uncertainties.
99 citations
TL;DR: In this paper, the effects of climate change on urban storm water runoff in the Bronx River watershed in New York City were studied using 134 general circulation models (GCMs) from the fifth phase of the coupled model intercomparison project (CMIP5) for a future time period of 2030-2059.
Abstract: In urban areas, there is concern that storm water runoff and flooding may be intensified because of the effect of climate change on precipitation amounts, intensities, and frequencies. Studies are needed to help storm water managers to plan and design effective adaptation and mitigation measures. This paper presents a study of the effects of climate change on urban storm water runoff in the Bronx River watershed in New York City. To show the effects of climate change on future precipitation, projections by 134 general circulation models (GCMs) from the fifth phase of the coupled model intercomparison project (CMIP5) are used. A new change factor method is proposed to select minimum, maximum, and mean daily precipitation scenarios for a future time period of 2030–2059. Because of the importance of short duration for extreme storm events, the daily precipitation is disaggregated to hourly increments. The U.S. Environmental Protection Agency storm water management model (SWMM) is used to model the hy...
89 citations
TL;DR: In this article, a new functional relationship between a dimensionless parameter involving stream power and settling velocity and the volumetric concentration at the transport limit was developed using a set of flume experiments with slope up to 46.6%, unit discharge up to 50 cm 2 ·s −1, median particle size of 0.326 mm, and sediment concentration up to 1,140 kg · m −3.
Abstract: The concept and estimation of sediment transport capacity of overland flows are pivotal to soil erosion, sediment transport, and deposition modeling. There is a limited understanding of the effect of high sediment concentration on the transport capacity of overland flow, although sediments in suspension are known to affect turbulent mixing and settling velocity in rivers. A new functional relationship between a dimensionless parameter involving stream power and settling velocity and the volumetric concentration at the transport limit was developed using a set of flume experiments with slope up to 46.6%, unit discharge up to 50 cm 2 ·s −1 , median particle size of 0.326 mm, and sediment concentration up to 1,140 kg · m −3 . The new relationship has two theoretical limits on sediment concentration at the transport limit. Under low flow conditions, the sediment concentration is limited by the available stream power. At high stream power, the sediment concentration is limited by the space available in flow to accommodate sediments in motion. As a predictor of the sediment concentration at the transport limit, the new relationship worked very well with the Nash-Sutcliffe coefficient of efficiency of 0.95 and was shown to be superior to empirical relationships based on stream power and other commonly used predictors of the transport capacity for rivers. The paper also shows that formulas for the transport capacity which have beenvalidated and widely used for rivers with high sediment concentrations are inaccurate and should not be used to predict the transport capacity of overland flow. DOI: 10.1061/(ASCE)HE.1943-5584.0000998. © 2014 American Society of Civil Engineers.
81 citations
TL;DR: In this paper, the potential evapotranspiration was estimated using 22 radiation-based methods and compared with the Food and Agriculture Organization of the United Nations (FAO) Penman-Monteith method.
Abstract: Evapotranspiration has a major role in agricultural and forest meteorology researches, hydrological cycle, irrigation scheduling, and water resources management. There are many methods to estimate the potential evapotranspiration including mass transfer, radiation, temperature, and pan evaporation-based methods. The present study aims to compare radiation-based methods to determine the best method under different weather conditions. The results discussed in this paper are from the data collected in the study area, but the method can be used in other similar regions. For this purpose, weather data was collected from 181 synoptic stations in 31 provinces of Iran. The potential evapotranspiration was estimated using 22 radiation-based methods and compared with the Food and Agriculture Organization of the United Nations (FAO) Penman-Monteith method. The results show that the Stephens method estimates the potential evapotranspiration better than other methods for provinces of Iran. However, the values ...
81 citations
TL;DR: In this article, the authors assess the risk of increase in water demand for a wide range of irrigated crops in an irrigation network located downstream of the Aidoghmoush Dam in East Azerbaijan by considering climate change conditions for the period 2026-2039.
Abstract: This paper assesses the risk of increase in water demand for a wide range of irrigated crops in an irrigation network located downstream of the Aidoghmoush Dam in East Azerbaijan by considering climate change conditions for the period 2026–2039. Atmosphere-ocean global circulation models (AOGCMs) are used to simulate climatic variables such as temperature and precipitation. The Bayesian approach is used to consider uncertainties of AOGCMs. Climate change scenarios of climatic variables are first weighted by using the mean observed temperature-precipitation (MOTP) method, and related probability distribution functions are produced. Outputs of AOGCMs are used as input to water requirement models. Then, produced by using the Monte Carlo method, 200 samples (discrete values) from the probability distribution functions of monthly downscaled temperature and precipitation in the study area are extracted by using a software for sensitivity and uncertainty analysis. Time series of climatic variables in fut...
76 citations
TL;DR: In this article, the spatiotemporal variations of the drought scenario over the Bundelkhand region in central India have been studied using the standardized precipitation index (SPI) for the time scales of 3, 6, and 12 months.
Abstract: The spatiotemporal variations of the drought scenario over the Bundelkhand region in central India have been studied using the standardized precipitation index (SPI) for the time scales of 3, 6, and 12 months. The space-time variability of the drought characteristics has been analyzed using the SPI, which is based only on long-term monthly rainfall data. From this analysis, it is determined that the frequency and severity of droughts have increased over the last decade in the Bundelkhand region and varied between once in 3 years and once in 5 years. The nonparametric Mann-Kendall test for trend analysis of climatic variables has been applied to investigate the regular occurrences of drought during the last few decades. The sign test indicates that there is a falling trend in the seasonal rainfall and number of rainy days in a few blocks. However, statistically significant falling trends at a 95% confidence level have been observed with the 3-month SPI for many blocks in the region, indicative of t...
73 citations
TL;DR: In this paper, the need for a generic catchment classification framework in hydrology has been emphasized and there have indeed been some attempts to advance the idea of such a classification framework, including river morphology, river regimes, hydroclimatic factors, landscape and land use parameters, hydrologic similarity indexes, hydrological signatures, ecohydrologic factors, geostatistical properties, entropy, nonlinear and chaotic properties, data mining, and other relevant characteristics and methods.
Abstract: The past few decades have witnessed the development of numerous catchment models, often with increasing structural complexity and mathematical sophistication. While such models have certainly provided a better understanding of catchments and associated processes, they are also often catchment-specific, region-specific, or process-specific. Serious concerns on this modeling trend have been increasingly raised in recent times and, consequently, the need for a generic catchment classification framework in hydrology has been emphasized. There have indeed been some attempts to advance the idea of such a classification framework. Such studies have investigated different ways of developing a framework, including river morphology, river regimes, hydroclimatic factors, landscape and land use parameters, hydrologic similarity indexes, hydrologic signatures, ecohydrologic factors, geostatistical properties, entropy, nonlinear and chaotic properties, data mining, and other relevant characteristics and methods...
70 citations
TL;DR: The long-standing issue of hydrological predictions in ungauged basins has received increased attention due to the recent International Association of Hydrological Sciences (IAHS) decade on predict...
Abstract: The long-standing issue of hydrological predictions in ungauged basins has received increased attention due to the recent International Association of Hydrological Sciences (IAHS) decade on predict ...
63 citations
TL;DR: The reliability of the low-impact development (LID) module of the widely used Storm Water Management Model (SWMM) for modeling the runoff reduction performance of permeable pavement systems was evaluated through example applications with rainfall data from Atlanta.
Abstract: The reliability of the low-impact development (LID) module of the widely used Storm Water Management Model (SWMM) for modeling the runoff reduction performance of permeable pavement systems was evaluated through example applications with rainfall data from Atlanta. The method of calculating infiltration through the pavement layers of permeable pavement systems of the LID module was found to be inadequate when the depths of the pavement layer are less than 120 mm and the computational time steps are longer than 30 min. An alternative method of representing permeable pavement systems as equivalent regular subcatchments is proposed. Using this method, the hydrologic operation of permeable pavement systems can be modeled by SWMM or other hydrologic models.
63 citations
TL;DR: In this article, a new drought index termed the soil moisture drought index (SODI) is developed to characterize droughts, which is based on how much water is required to attain soil moisture at field capacity.
Abstract: A new drought index termed the “soil moisture drought index (SODI)” is developed to characterize droughts. The premise of the index is based on how much water is required to attain soil moisture at field capacity. SODI captures variations of precipitation, temperature, and soil moisture over time. Three widely used drought indices, including the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), and the self-calibrated palmer drought index (sc-PDSI) are compared with SODI along with local hydrological variables such as streamflow, reservoir storage, and groundwater level for cross-validation. The result indicates that SODI reacts more evidently to relate changes in precipitation and temperature than SPI and SPEI by characterizing soil moisture over time. Results also show that SODI outperforms the existing drought indices in the sense that SODI can detect and quantify the extended severe droughts associated with climate variability and change. S...
TL;DR: A nonparametric technique is proposed as an alternative to parametric error models to estimate the uncertainty of hydrological predictions, and it is proved that the results obtained are compared with those obtained using a formal statistical technique from the same case study.
Abstract: Estimating the uncertainty of hydrological models remains a relevant challenge in applied hydrology, mostly because it is not easy to parameterize the complex structure of hydrological model errors. A nonparametric technique is proposed as an alternative to parametric error models to estimate the uncertainty of hydrological predictions. Within this approach, the above uncertainty is assumed to depend on input data uncertainty, parameter uncertainty and model error, where the latter aggregates all sources of uncertainty that are not considered explicitly. Errors of hydrological models are simulated by resampling from their past realizations using a nearest neighbor approach, therefore avoiding a formal description of their statistical properties. The approach is tested using synthetic data which refer to the case study located in Italy. The results are compared with those obtained using a formal statistical technique (meta-Gaussian approach) from the same case study. Our findings prove that the nea...
TL;DR: In this paper, the authors have generated future precipitation by downscaling general circulation model (GCM, HADCM3) data of A2 scenario in a part of the Narmada River Basin in Madhya Pradesh, India, to obtain future impact of climate change on soil erosion.
Abstract: Soil erosion is one of the major hazards affected by the climate change, particularly the changed precipitation trend. The present paper has generated future precipitation by downscaling general circulation model (GCM, HADCM3) data of A2 scenario in a part of the Narmada River Basin in Madhya Pradesh, India, to obtain future impact of climate change on soil erosion. Least-square support vector machine (LS-SVM) and statistical downscaling model (SDSM) models were used for downscaling, and the universal soil loss equation (USLE) model was used for estimating soil loss. The results were analyzed with different slope, land use, and soil category. Outcome showed an increase in future precipitation with the resultant increase in soil erosion, with a positive change of 18.09 and 58.9% in years 2050s and 2080s respectively in LS-SVM, while it is decreasing in the year 2020s (−5.47%). Rate of change of soil erosion with SDSM is 15.52 and 105.80% in years 2050s and 2080s respectively, and decrease in the 20...
TL;DR: In this article, a neuro-fuzzy-based group method of data handling (NF-GMDH) as an adaptive learning network is used to predict the flow discharge in straight compound channels.
Abstract: In this study, neuro-fuzzy-based group method of data handling (NF-GMDH) as an adaptive learning network is used to predict the flow discharge in straight compound channels. The NF-GMDH network is developed by using the particle swarm optimization (PSO) and gravitational search algorithm (GSA). The depth ratio (ratio of water depth in floodplain to that in main channel), coherence parameter, and the discharge ratio [ratio of flow discharge calculated from vertical divided channel method (VDCM) to the bank full discharge] are considered as input parameters to represent a functional relationship between input and output parameters. The performances of training and testing stages for NF-GMDH models were quantified in terms of statistical error parameters. Also, the results of performances were compared with those obtained by using linear genetic programming, nonlinear regression methods, and VDCM. Evaluation of the proposed model demonstrated that NF-GMDH-GSA network provides a more accurate predicti...
TL;DR: In this article, a method to maximize the contribution of an atmospheric river on precipitation over each of the targeted watersheds is proposed, which shifts the atmospheric boundary conditions of the regional atmospheric model in space with latitude and longitude.
Abstract: Maximum precipitation during a historical period is estimated by means of a physically based regional atmospheric model over three watersheds in Northern California: the American River watershed (ARW), the Yuba River watershed (YRW), and the Upper Feather River watershed (UFRW). In Northern California, severe storm events are mostly caused by a high-moisture atmospheric flow from the Pacific Ocean, referred to as atmospheric river (AR). Therefore, a method to maximize the contribution of an AR on precipitation over each of the targeted watersheds is proposed. The method shifts the atmospheric boundary conditions of the regional atmospheric model in space with latitude and longitude so that the AR strikes each of the targeted watersheds in an optimal direction and location to maximize the precipitation over these watersheds. For this purpose, the fifth generation Penn State/National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) is used as the regional atmospheric model, and the NCAR/...
TL;DR: In this paper, the modified honey bee mating optimization (MHBMO) algorithm with the modified routing procedure is used for the estimation of Muskingum parameters using two different objective functions.
Abstract: Because the nonlinear Muskingum model continues to be popular, the need for precise calibration of the model parameters provides an active area of research in hydrologic engineering. Although various techniques have been proposed to estimate the three parameters in the nonlinear Muskingum model, a more accurate method with the fast convergence rate is still required to improve the computational precision. In this research, the modified honey bee mating optimization (MHBMO) algorithm with the modified routing procedure is used for the estimation of Muskingum parameters using two different objective functions. The proposed algorithm is applied to two case studies from previous literature and the results are compared with those of other methods. The results demonstrate that the MHBMO algorithm not only converges fast but it also captures the best optimal parameter values. The sensitivity analyses, carried out on the MHBMO algorithm control parameters, show that for each parameter, the results are sta...
TL;DR: In this article, a stepwise-clustered hydrological inference (SCHI) model was developed for daily streamflow forecasting, which uses cluster trees to represent the nonlinear and complex relationships between streamflow and multiple factors related to climate and watershed conditions.
Abstract: Flow prediction is one of the most important issues in modern hydrology. In this study, a statistical tool, stepwise-clustered hydrological inference (SCHI) model, was developed for daily streamflow forecasting. The SCHI model uses cluster trees to represent the nonlinear and complex relationships between streamflow and multiple factors related to climate and watershed conditions. It allows a great deal of flexibility in watershed configuration. The proposed model was applied to the daily streamflow forecasting in the Xiangxi River watershed, China. The correlation coefficient for calibration (1991–1995) was 0.881, and that for validation (1996–1998) was 0.771. Nash–Sutcliffe efficiencies for calibration and validation were 0.768 and 0.577, respectively. The results were compared to those of a conventional process-based model, and it was found that the SCHI model had a superior performance. The results indicate that the proposed model could provide not only reliable and efficient daily flow predic...
TL;DR: In this article, the authors discuss the role of dams on development and highlight the importance of dams as an integral part of basic infrastructure by offering indispensable benefits like irrigation, hydropower, domestic and industrial water supply, flood control, drought mitigation, navigation, fish farming, and recreation.
Abstract: Dams have become an integral part of basic infrastructure by offering indispensable benefits like irrigation, hydropower, domestic and industrial water supply, flood control, drought mitigation, navigation, fish farming, and recreation. As controversial as they have been during the last decades due to negative social and environmental impacts, the limited and uneven distribution of water at the global level has made the world realize that more dams, mostly large dams, are needed if development is to be promoted and if basic human needs are to be covered. Overall, it has been global dynamics in terms of water, energy (including trade aspects), food, and climate securities that has recasted the role of dams triggering massive investment on construction and modernization of multiple projects all over the world. It is thus fundamental to continue improving project planning and implementation to avoid unnecessary social and environmental costs. This paper discusses the role of dams on development, hydr...
TL;DR: Low-cost aquifer storage and recovery (ASR) schemes were constructed at 13 villages in three coastal districts by developing storage in shallow confined fine to medium sand aquifers overlain by variable thicknesses of silt and clay as mentioned in this paper.
Abstract: Fresh water resources are scarce in rural communities in the southern deltaic plains of Bangladesh where both shallow and deep groundwater is frequently brackish, and fresh water ponds have been increasingly salinized by inundation during storm surges and brackish-water aquaculture. Low-cost aquifer storage and recovery (ASR) schemes were constructed at 13 villages in three coastal districts by developing storage in shallow confined fine to medium sand aquifers overlain by variable thicknesses of silt and clay. A typical ASR scheme consisted of a double-chambered graded sand filtration tank with a volume of 19.5 m3 that feeds filtered pond water to four to six large diameter (d=30.5 or 56 cm) infiltration wells through PVC pipes fitted with stop valves and flow meters. The infiltration wells were completed at 18–31 m below ground and filled with well-sorted gravel capped with a thin layer of fine sand that acts as a second stage filter. Infiltration rates at 13 sites averaged 3 m3/day (range: 3–...
TL;DR: In this paper, a physics-based two-dimensional numerical model is presented to simulate overland flows typically generated by rainfall of a storm event or multiple events in natural terrain with complex topography, landform, soil characteristics, and land use.
Abstract: This paper presents a physics-based two-dimensional (2D) numerical model to simulate overland flows typically generated by rainfall of a storm event or multiple events in natural terrain with complex topography, landform, soil characteristics, and land use. The model is based on the 2D fully nonlinear shallow-water equations (SWEs) in which tempospatial variations of rainfall intensity and infiltration are taken into account as source and sink terms, respectively. The Green-Ampt equation is used to simulate infiltration. Due to strong nonlinearity of the coupled dynamic processes in overland flow and stormwater runoff, special efforts were made to solve this coupled-flow system under the conditions of unsteady rainfall intensity and natural terrain. To attain the modeling capabilities for multiple flow regimes including subcritical, supercritical, and the transitions, a second-order central-upwind shock-capturing scheme, which is well balanced and depth-positivity preserving, is used to solve the ...
TL;DR: In this paper, the authors investigated the hydrological impacts of the Poyang Lake Project using a two-dimensional Environmental Fluid Dynamics Code (EFDC) model, which will be helpful to evaluate the advantages and disadvantages of the building of PLP.
Abstract: Dams have great hydrological impacts on the river system. Poyang Lake, the largest freshwater lake in China, has experienced severe drought over the past decade since the operation of the Three Georges Dam. The Jiangxi Province Government proposed to build a 2.8-km-wide dam with sluice gates across the narrowest part of the channel that links Poyang Lake and Yangtze River, called the Poyang Lake Project (PLP), to solve the problem of drought. The proposal caused concerns about the negative effect of increased water level on wintering birds’ habitat and water quality. But so far, little scientific data have been provided to evaluate the hydrological impacts of the PLP. The aim of this study is to investigate the hydrological impacts of the PLP using a two-dimensional Environmental Fluid Dynamics Code (EFDC) model based on the latest regulation scheme, which will be helpful to evaluate the advantages and disadvantages of the building of PLP. The model was calibrated and verified by comparing model p...
TL;DR: In this paper, the authors developed a hydrograph model able to quantify these separate runoff volumes to help in estimation of runoff processes and residence times used by watershed managers, using parallel application of two advection-diffusion equations and calibrating the model's fast and slow time parameters.
Abstract: Two-peak hydrographs after a single rain event are observed in watersheds and storms with distinct volumes contributing as fast and slow runoff. The authors developed a hydrograph model able to quantify these separate runoff volumes to help in estimation of runoff processes and residence times used by watershed managers. The model uses parallel application of two advection-diffusion equations and calibrates the model’s fast and slow time parameters as well as a coefficient representing the relative size of the smaller hydrograph peak. The model provides an accurate representation of hydrograph timing, volume, peak, points of inflection, and recession rate, and its parameters represent physical processes of advection and diffusion and relate to watershed scale. The authors calibrated the model to match observed two-peak hydrographs with high efficiency on a watershed with distinct urban and rural land cover, and another watershed with distinct fast runoff from saturated areas. The Nash–Sutcliffe ef...
TL;DR: In this article, a regional atmospheric model over three watersheds in northern California was used to estimate the maximum precipitation (MP) by means of a regional weather model over the historical severe storms that were recorded over these target watersheds.
Abstract: Maximum precipitation (MP) was estimated by means of a regional atmospheric model over three watersheds in northern California [(1) the American River watershed (ARW), (2) the Yuba River watershed (YRW), and (3) the Upper Feather River watershed (UFRW)], based on the reconstruction and analyses of the historical severe storms that were recorded over these target watersheds, and where the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data were available for regional atmospheric modeling of the historical storms. Since severe storm events are mainly caused by atmospheric rivers (ARs) in northern California, the contribution of an AR on precipitation over each of the targeted watersheds is maximized to estimate the 72-h MP. For this purpose, the moisture of ARs is maximized after shifting the regional atmospheric model’s atmospheric boundary conditions (BCs) in space with respect to latitude and longitude so that the AR strikes each of...
TL;DR: In this article, a 1D hydrologic-hydraulic model for simulating dual drainage in urban areas is presented, which consists of four modules: (1) rainfall runoff transformation, (2) 1D flow routing on a street network, (3) flow interception at street inlets, and (4) flow interaction between surface water on the streets and the underground storm-water system by interfacing with the EPA-SWMM5 engine.
Abstract: A one-dimensional (1D) hydrologic-hydraulic model for simulating dual drainage in urban areas is presented. It consists of four modules: (1) rainfall-runoff transformation, (2) 1D flow routing on a street network, (3) flow interception at street inlets, and (4) flow interaction between surface water on the streets and the underground storm-water system by interfacing with the EPA-SWMM5 engine (U.S. Environmental Protection Agency-Storm Water Management Model). The hydrologic model (first module) transforms rainfall to runoff using the kinematic wave approximation and simulates the infiltration process with the Green-Ampt method. The street network model (second module) is based on a finite-volume shock-capturing scheme that solves the fully conservative Saint-Venant equations and can be used to model both subcritical and supercritical flows. The inlet model (third module) computes the amount of water intercepted by inlets. The formulation of boundary conditions at the street crossings is generaliz...
TL;DR: In this article, a 1D hydrodynamic model is coupled with a 2D hydrostatic model for the prediction of water levels in the lower Tapi River and its coastal urban floodplain (Surat city in Gujarat, India).
Abstract: In this work, a one dimensional–two dimensional (1D–2D) coupled hydrodynamic model is developed for prediction of water levels in the lower Tapi River and its coastal urban floodplain (Surat city in Gujarat, India). A one-dimensional (1D) hydrodynamic model, calibrated for the 1998 flood, is coupled with a two-dimensional (2D) hydrodynamic model of an urban floodplain with due consideration of the upstream (releases from Ukai reservoir) and downstream (tidal level of the sea) boundary conditions. The resistance coefficient for the floodplain is estimated using satellite imagery based on the land use and land cover pattern. The coupled hydrodynamic model is validated with independent data for flooding in the year 2006 and is used to develop a stage-discharge curve along the lower Tapi River for computation of the stream power during the flood. The methodology for river flood prediction on a coastal urban floodplain using the 1D–2D coupled hydrodynamic model is generic and can be applied to similar ...
TL;DR: In this article, an index named as standardized precipitation anomaly index (SPAI) is proposed for the meteorological drought quantification in the context of the monsoon-dominated climatology, where the precipitation is strongly seasonal and periodic.
Abstract: In this study, an index, named as standardized precipitation anomaly index (SPAI), is proposed for the meteorological drought quantification in the context of the monsoon-dominated climatology, where the precipitation is strongly seasonal and periodic. In the computation of SPAI, the anomalies of the precipitation are normalized rather than normalizing the raw precipitation series. The SPAI is compared with the standardized precipitation index (SPI), with respect to certain shortcomings of the latter. It is shown that the SPAI, owing to its design, is able to successfully differentiate between the consequences of shortages/surplus in rainfall in the monsoon and nonmonsoon months which is not possible through SPI. The unique suitability of SPAI for monsoon dominated regions is also illustrated by comparing its premise of development with that of the standardized nonstationary precipitation index (SnsPI). Further, drought quantification through the SPAI is shown to be applicable for both periodic an...
TL;DR: In this article, the authors proposed a new flow-routing model called runoff coefficient routing model (RCRM), which is simple and requires limited data, such as precipitation, LULC and streamflows as compared to other models, which require meteorological and many more input data.
Abstract: Land use–land cover change (LULC) has considerable impacts on hydrologic response at the watershed level. Quantitative assessment of LULC impacts on runoff generations is vital for water resources development. The soil and water assessment tool (SWAT) model was used to study the effect of LULC change on streamflows. In addition to this, the present study proposed a newly developed flow-routing model called runoff coefficient routing model (RCRM). This new model is simple and requires limited data, such as precipitation, LULC and streamflows as compared to other models, which require meteorological and many more input data. The Nethravathi River basin was selected for testing the RCRM model with the SWAT model to study land use–land cover change on streamflows. The SWAT model and RCRM model have been calibrated for 2001–2005 and validated for 2006–2009 daily data. Results have shown that the simulated streams are well correlated with observed streamflows with a coefficient of correlation (R2) equal...
TL;DR: In this article, a hydraulic model of a 150-km reach of the Danube River was built by using SRTM topography as input data and radar altimetry of the 2006 flood event as calibration data.
Abstract: Flood inundation modeling is one of the essential steps in flood hazard mapping. However, the desirable input and calibration data for model building and evaluation are not sufficient or unavailable in many rivers and floodplains of the world. A potential opportunity to fill this gap is offered nowadays by global earth observation data, which can be obtained freely (or at low cost), such as the shuttle radar topography mission (SRTM) and radar altimetry. However, the actual usefulness of these data is still poorly investigated. This study attempts to assess the value of SRTM topography and radar altimetry in supporting flood-level predictions in data-poor areas. To this end, a hydraulic model of a 150-km reach of the Danube River was built by using SRTM topography as input data and radar altimetry of the 2006 flood event as calibration data. The model was then used to simulate the 2007 flood event and evaluated against water levels measured in four stream gauge stations. Model evaluation allows th...
TL;DR: In this paper, the authors investigated the impact of climate change on flood frequency in Bagmati River Basin of Nepal using bias-corrected global climate model (GCM) precipitation output.
Abstract: In this paper, climate change impact on flood frequency has been investigated in Bagmati River Basin of Nepal using bias-corrected global climate model (GCM) precipitation output. The research reported in this paper employed a high-resolution (approximately 20-km) daily GCM precipitation and temperature output of Meteorological Research Institute (MRI), Japan. Comparison of observation and GCM data pointed out that the MRI-GCM precipitation consists of significant biases in frequency and intensity values. Quantile-quantile mapping method of GCM bias correction was applied for minimizing the biases in precipitation frequencies and intensities. Concept of homogeneous precipitation regions was introduced to link the uneven observation data stations and GCM grid cells. Analyses of return period curves, shape, and scale factors at different observation stations enabled delineation of three homogeneous precipitation regions. Accordingly, regional quantile-quantile bias-correction technique was developed...
TL;DR: In this article, a packed column test was employed to investigate the behavior of flow through granular materials, and it was observed that the relationship between velocity and hydraulic gradient are nonlinear and why it is called non-Darcy flow.
Abstract: In order to investigate the behavior of flow through granular materials, a packed column test was employed. The laboratory model consisted of a permeameter having 0.2 m diameter and 1 m length. Two kinds of crushed and rounded gravel particles with six different sizes were used as porous materials. By using flow velocity–hydraulic gradient relationships, it was observed that the relationships between velocity and hydraulic gradient are nonlinear and why it is called non-Darcy flow. Evaluating the results of this research for both kinds of aggregates by means of statistical indicators and comparison of different relationships showed the best empirical equation. The relation between Reynolds number and diameter of materials indicated that the friction factor for higher Reynolds numbers decreased and reached to a constant value for both kinds of materials.