Forthcoming articles

 


International Journal of Hydrology Science and Technology

 

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International Journal of Hydrology Science and Technology (63 papers in press)

 

Regular Issues

 

  • Evaluation of Clark IUH in Rainfall-Runoff Modeling (Case Study: Amameh Basin)   Order a copy of this article
    by Meysam Salarijazi, Mohammad Abdolhosseini, Khalil Ghorbani, Saeid Eslamian, Iman Ahmadianfar 
    Abstract: The application of Clark IUH in Amameh basin, Iran is investigated in this study. Six recorded rainfall-runoff events were selected. Calibration results showed great changes in the calibrated parameters, percentage error in peaks and volumes (PEP and PEV), and the model efficiency (EFF) while percentage error in time to peak (PTEP) had always low values. Furthermore, the simulations of falling limbs of runoff hydrographs were better than rising limbs. Validation results indicated that time to peaks, runoff volumes, and falling limbs of runoff hydrographs were much better predicted than peak discharges, rising limbs, and total shapes of runoff hydrograph. One way sensitivity analysis revealed that the storage coefficient was more sensitive than time of concentration and EFF, PEP, PETP, and PEV had highest to lowest sensitivity. It can be concluded that the estimation of time to peak and runoff volume had higher performance than runoff hydrograph shape and peak discharge.
    Keywords: Clark IUH; Rainfall-Runoff Model; Sensitivity Analysis; Model Efficiency.

  • Determination of the height of vertical filter in heterogeneous earth dams with vertical clay core   Order a copy of this article
    by Mohammad Shayannejad, Saeid Salehi-Hafshejani, Hossein Samadi Boroujeni, Ali-Reza Zarraty, Bahareh Soltani, Kaveh Ostad-Ali-Askari 
    Abstract: In order to determine the height of the filter in heterogeneousearthdam, three embankment models were provided in a flume laboratory, with the length of 4.2 m at the base of dam, the width of 60 cm and the height of 1 m and bodyslope1H: 2V. For embankment of model,two types of fineand coarsegrained soils were used. The texture of the soil was made using hydrometer method. In the first model,the fine-grained and coarse-grained soils were used in downstream and upstream of the dam crest respectively. In Models2and3 with cutting fine grained soil from the toe of the dam to the dam crest,vertical clay core was replaced.Index of a / L (athickness of clay core and L is the length of base dam) was 1.7 and 1.10 in the second and third models respectively.Seepage experiments in 3 water height of 80and55and30 were performed.The phreatic surface was determined using wells and 30 embedded Piezometer in the models. Then rate of falling head due to clay core was measured and it compared with software PLAXIS V8.5 results.The clay core of height of filterwith safety factor 1.2 (Encounter Line Leak with 20% of the bottom filter)was introduced.The hydraulic conductivity of theclay were affected decline of water level.
    Keywords: Model of heterogeneous earth dam; HeightofFilter; thickness ofthe clay core; software PLAXIS V8.5.

  • Monitoring and prediction of drought by Marcov chain Model based on SPI and new index (SPEI) in Isfahan   Order a copy of this article
    by Saeid Eslamian, Mahsa Jahadi 
    Abstract: Abstract: Drought evaluation and associated prediction are essential for water resource management. Most of previous studies analyzed and predicted drought pattern in Isfahan based on the standardized precipitation index (SPI). Due to the high evapotranspiration in Isfahan, the SPI index which is based on precipitation alone may not be sufficient to monitor and estimate drought pattern. So it is vital to analyze and predict drought phenomenon at this region based on the new index (SPEI) that considers potential evapotranspiration in addition to the precipitation. Hence drought analysis is performed based on SPI and SPEI (standardized precipitation- evaporation index) in Isfahan. The results indicate that there is some difference between two indices. Finally SPEI and the Marcov Chain model are applied to predict the drought patterns in a 30 years period in the long term future. It is predicted that the percentage of aridity state will increase comparison with the past decade.
    Keywords: Keywords: Drought monitoring; Drought prediction; Isfahan; Iran; Markov chain model; SPEI index; SPI index.

  • Urban water consumption in water-stressed areas of the developed world: An examination of multiple interrelated variables   Order a copy of this article
    by Alvaro-Francisco Morote, María Hernández, Saeid Eslamian 
    Abstract: The developed world has witnessed significant land changes since the second half of the twentieth century. These include a process of intensive urban development, which is also accompanied by the growth in the urban population and housing. One of the outcomes of this process has been an increase in the consumption of resources, including water. The aim of this paper is to identify and analyse the factors affecting water consumption and the areas studied in water-stressed regions of the developed world. A literature review of territorial studies examining the factors that affect urban water consumption in these areas was conducted methodologically. The results reveal that: a) a significant number of papers have been written on water consumption factors in areas where there is substantial urban growth; and b) North America and Australia, have been compared to the rest of the developed world (especially Southern Europe), recently (since 2000s) due to the expansion of the low-density urbanism in the last few years.
    Keywords: water; urban; factors; consumption; water-stressed areas; developed world.
    DOI: 10.1504/IJHST.2018.10007714
     
  • Potential Impacts of Climate Change on Precipitation Patterns over Iran (An Arid/Semi-Arid Climate)   Order a copy of this article
    by Jaber Rahimi, Ali Khalili 
    Abstract: In this study, two objectives were paramount. One is to assess the spatio-temporal patterns of precipitation in Iran and the other is to investigate the projected changes in these patterns for the period 20712100 as compared to 19652010. These were achieved by using monthly precipitation data from 256 rain gauge stations and the outputs of the HadCM3 global circulation model (under the A2 and B2 scenarios). The statistical (Delta Method) and dynamical (PRECIS) downscaling techniques were compared in terms of their results for projecting annual isohyets, annual march of monthly precipitation and the precipitation homogeneity. The results showed that, by HadCM3_Delta Method_A2, HadCM3_Delta Method_B2, HadCM3_PRECIS_A2 and HadCM3_PRECIS_B2 projections, the annual mean precipitation over the country (which is already 254 mm) would be 208.6, 187.1, 174.1 and 175.0 mm, respectively. Also, the corresponding values for the average of precipitation homogeneity index would change from 57% in the current conditions to 53, 54, 59 and 61 % in climate change conditions, respectively. Although temporal and spatial monthly precipitation was envisaged, there was no impressive impact of climate change on precipitation pattern, but it's effect on time of maximum precipitation was subtle.
    Keywords: Intra-Annual Precipitation Regimes; Climate Change; Downscaling; Iran.

  • Reducing Water Shortage Crisis Through Rainwater Reuse: Lessons Learned from Ancient Toward Integrated Technology   Order a copy of this article
    by Saeid Okhravi, Saeid Eslamian, Nicolas R. Dalezios 
    Abstract: The quantity of freshwater available per person in the world has been proceeded to decrease due to a combination of factors, including population increase, water pollution, inadequate planning and management of transboundary water, and inefficient operation of water supply and distribution systems. There is a direct water source to cease increasing potential for water scarcity, crisis and associated conflicts around the world in the future called rainwater harvesting that is an ancient technique enjoying a revival in popularity due to the inherent quality of rainwater and interest in reducing consumption of treated water. Rainwater harvesting is included as an innovative site design strategy to minimize runoff based on LID practices. The present study on literature attempts to offer a comprehensive account of the above issues and also some important guidelines for advancing research in this direction. Assessments of past, present and future statuses of the worlds water are reviewed.
    Keywords: Climate change; LID; Rainwater harvesting; Stormwater management; Water crisis.

  • GROUNDWATER FLOW PATTERNS IN THE OBAGI OIL FIELDS OF SOUTH-SOUTH NIGERIA   Order a copy of this article
    by Ifeanyichukwu Ezekwe, Chukwuma Oji 
    Abstract: This study was an attempt to decipher groundwater flow patterns and the factors that affect it in the Obagi Oil Fields of South-South Nigeria. In this study, head, position and geological data were obtained from 13 hand dug wells tapping the water table and the Sombreiro and the Orashi Rivers, while water quality data was generated through groundwater sampling and analysis using standard methods. This study discovered a hidden channel system, a reversed recharge system for the Sombreiro River system with serious local groundwater quality implications. Groundwater flow in the study area has components of regional, intermediate and local flow systems, while movement is controlled by topography; recharge; a groundwater channel system running NW-SE through the middle of the study area and a system of wetlands in the Omoku and Erema areas. These wetlands which are used as sinks are also major recharge areas for the groundwater system in the study area thereby posing public health dangers. Also the dumping of industrial and domestic wastes in the wetlands may be limiting the capacity of these wetlands as sinks and purification plants for the natural hydro-geopollution cycle.
    Keywords: Water Quality; Groundwater Channels; Groundwater controls; Tothian flow; Orashi; Sombreiro.

  • Dynamic parameter estimation for hydrological model   Order a copy of this article
    by Shailesh Kumar Singh 
    Abstract: Hydrological models are frequently used for forecasting, water management and decision making in watershed development. Due to simplification of complex natural processes in a hydrological model and the limited availability of observations, parameters of these models cannot be identified precisely during model calibration. Parameters of models are commonly assumed to be time independent even though some catchment properties are not stationary. The flexibility of hydrological models can be increased by introducing dynamic variation in the parameters of a hydrological model. In turn, this will improve the representation of natural processes. The purpose of this paper is to develop a methodology to investigate the dynamic nature of model parameter. A Robust Dynamic Parameter Estimation (RDPE) algorithm is developed which can be used for model diagnosis as well as for improving model predictions by allowing for parameter time dependence. After identification of the range of time varying parameters, a moving window approach and simulated annealing are used to optimize the parameters of the HBV (Hydrologiska Byrans Vattenavdelning) hydrological model for the each window size. The resulting time series of parameters are used for defining sensitive and insensitive periods in parameter time series and for understanding the reasons for parameter variation in time. To improve predictions a predictive parameter model is developed and applied using HBV model on meso-scale catchments in the Neckar basin in South-West Germany using HBV model. Finally, it is shown that the new methodology leads to more realistic confidence intervals for model simulations and model structure identification.
    Keywords: Time varying parameters; RDPE algorithm; HBV; Parameter estimation.

  • Contribution of the multivariate analysis and origin for groundwater quality of mixed aquifer in the Msila plain (Algeria)   Order a copy of this article
    by Mostefa Dougha, Mahmoud Hasbaia 
    Abstract: The change of climate and intensive exploitation of groundwater resources in the plain of Msila has influenced the hydrochemical functioning of the complex aquifer. This resulted in a decrease in the piezometric level of groundwater. The multivariate statistical techniques were used to determine the main factors and regrouping parameters/wells and to understand the origin of groundwater chemistry. Multivariate analysis (principal component analysis and cluster analysis) was performed to identify a common source for sampling data of a semi-arid aquifer. Physicochemical analyses were conducted on the waters of 17 wells. The chemical water classification shows the dominance of a chlorinated calcium and magnesium sulphate type facies, which has a very remarkable tendency towards the salinisation. Cluster analysis based on major parameters contents defined four main chemical water groups with increased water-rock interaction. Some parameters presented the highest concentrations of the total of dissolved salts provoking a poor quality of water.
    Keywords: multivariate analysis; PCA technique; HCA technique; piper; hydrochemical facies; water quality; origin of groundwater; salinity; mixed aquifer; M’sila plain.
    DOI: 10.1504/IJHST.2019.10010624
     
  • Optimal Control Applied to an Irrigation Planning Problem : a real case study in Portugal   Order a copy of this article
    by Sofia O. Lopes, Rui M.S. Pereira, Paulo A. Pereira, Amélia C. Caldeira, Victor Francisco Fonte 
    Abstract: In this paper, a daily plan model to the irrigation of a crop field using optimal control was developed. This daily plan model have in consideration: weather data (temperatures, rainfall, wind speed), the type of crop, the location, humidity in the soil at the initial time, the type of soil and the type of irrigation. The aim is to minimise the water used in the irrigation systems ensuring that the field crop is kept in a good state of preservation. MATLAB was used to develop our mathematical model and obtain its output. Its results were compared with experimental ones obtained from a real farm field of grass in Portugal. This comparison not only allowed us to validate our model, but also allowed us to conclude that, using optimal control considerable savings in water resources, while keeping the crop safe are obtained. Some real test cases were simulated and the comparison between the optimised water to be used by the irrigation system (calculated by software) and the real amount of water used in irrigation site (on-off control system for irrigation) produced water savings above 10%.
    Keywords: optimal control; irrigation systems; real data; water resources; Portugal.
    DOI: 10.1504/IJHST.2019.10009095
     
  • INVESTIGATION ON WATER CONTENT OF SELECTED AGRICULTURAL PRODUCTS OF EAST AZARBAIJAN AND WEST AZARBAIJAN   Order a copy of this article
    by Marzieh Momeni, Zahra Zakeri, Sina Zahedi, Vahid Razavi 
    Abstract: According to a numerous environmental sustainability indicators, Iran is considered to be in an undesirable situation. Meanwhile "critical water crisis" is one of the most fundamental problems that decision and policy makers are facing. Thus, analyzing and coming up with solutions for the current water crisis is of outmost importance. The current study intends to focus on East and West Azarbaijan, in which Lake Urmia basin covers main part of this area. According to the sustainable development index of The United Nations Educational, Scientific and Cultural Organization (UNESCO) for water resources, this basin is exposed to extremely high risks of drought (High Risk Category> 40 %). Statistics indicate that the total amount of water consumption for selected agricultural products, in these provinces, is approximately 9.52 Billion Cubic Meters (BCM). In other words, agriculture sector consumes almost 91.8 % of allocated water in this area. For a better understanding of the current situation, this research focused on the water consumption in agriculture sector. Furthermore, by using partial equilibrium method, real virtual water content, calculated by amount of allocated water, was compared to that calculated based on water requirement of selected products. The results show that for production of one unit per kilogram, real water consumption is more than water requirement indicating that averaged value of water efficiency for producing most of the agricultural products in East/West Azarbaijan is almost 21%. Due to the water crisis, appropriate policies should be made to improve efficiency of water consumption in this area.
    Keywords: Real Virtual Water Content; Water Consumption Efficiency; Partial Equilibrium; East Azarbaijan; West Azarbaijan.

  • An assessment of Water Resources at Halayib and Shelatine Sub regions, Southeastern Desert, Egypt, Using Conventional and Isotopic Approaches   Order a copy of this article
    by Samir Al-Gamal 
    Abstract: Surface water resources are expressed as potential surface runoff of ten watersheds in Halayib and Shelatine sub regions. Hydrologic response of the studied watersheds subjected to single storm event is tested. Base flow source areas and major recharge areas were delineated by infiltration using conventional infiltrometer and the water isotopes of O-18 and H-2. Aerial and linear aspects of each watershed were defined and due to paucity of runoff data, potential runoff was determined according to Snyders equation (1938). Groundwater resources are represented by two main aquifers; those pertaining to wadi fill and alluvial deposits of Quaternary aquifers resting unconformably over fluviatile sandstone of Um-Barmil Formation of Upper Cretaceous age. The Quaternary aquifer is receiving direct recharge from the present day precipitation as a consequence of infiltration from runoff water; particularly for soil of high infiltration capacity (7 mm/h).This represents the first pole of water while paleowater derived from the fluviatile sandstones of the tectonically dissected Um-Barmil Formation of Upper Cretaceous age represents the 2nd pole of water. Stable isotopes of O-18 and H-2 have proven the hydraulic connection between those two main aquifers. The foregoing situation has resulted in mixing of the two water types. The δ18O and δ2H values suggest a local meteoric line (whose slope of 5), characterizing low intensity, short duration rainfall, which partially were being evaporated during their precipitation.
    Keywords: groundwater; surface water; infiltration;environmental isotopes; d-excess; aquifer;watershed.

  • Climate modeling using ANN   Order a copy of this article
    by Mehnaza Akhter, Manzoor Ahanger 
    Abstract: In the present study artificial neural network (ANN) model was applied to monthly temperature and precipitation data for base time (19792009) at four different metrological stations vis Srinagar, Pahalgam, Qazigund and Gulmarg of river Jhelum basin in the State of Jammu and Kashmir, India and the future average annual temperature and precipitation predicted up to 2100. The large scale GCM predictors were related to observed precipitation and temperature and future projections of climate were made under A1B and A2 scenario upto 21st century. At the end of the 21st century the mean annual temperature of the Jhelum river basin is predicted to increase by 1.43
    Keywords: artificial neural network; ANN; Srinagar; Pahalgam; Qazigund; Gulmarg; scenario; temperature; precipitation.
    DOI: 10.1504/IJHST.2019.10016868
     
  • Constructing Depth-Area-Duration Curves using Public Domain Satellite-Based Precipitation Data   Order a copy of this article
    by MARINA PATRICK, Yau Seng Mah, Frederik Josep Putuhena, Yin Chai Wang, Onni Suhaiza Selaman 
    Abstract: Dense network of rain gauges are used to accurately characterize the variation of rainfall over a less than ideal region such as Sarawak, Malaysia. This research aims to develop depth-area-duration (DAD) relationships of selected rainstorm event over Sungai Sarawak Basin by using public domain satellite-based precipitation data from Tropical Rainfall Measuring Mission (TRMM) product. Geographic Information System (GIS) was used to manipulate the 3-hourly accumulated precipitation dataset from TRMM and subsequently used to investigate spatial and temporal pattern of rainstorm. The findings suggested that rainfall depth decreases with increasing area for a given duration. This also implies that the remotely sensed information from TRMM product can be used as an alternative source of dataset to envelop rainfall DAD curves. Future work suggested would be to use the plotted DAD curves to estimate the probable maximum precipitation for the purpose of hydraulic structure designs.
    Keywords: Areal rainfall; depth-area-duration; extreme rainstorm event; Geographic Information System; isohyets; Kriging; North-East Monsoon; Sungai Sarawak Basin; Thiessen Polygon; Tropical Rainfall Measuring Mission.

  • Comparison of perturbation methods for rainfall and temperature data: case of a Belgian catchment   Order a copy of this article
    by Yann Peltier, Benjamin Dewals, Sebastien Erpicum, Michel Pirotton, Pierre Archambeau 
    Abstract: Analyses of hydrological impacts of climate change require appropriate methods for perturbing the rainfall and temperature (or evapotranspiration) time-series to represent future climate conditions. In this paper, two readily available tools for perturbing rainfalls and temperatures are compared: CCI-HYDR and KNMI-ADC. CCI-HYDR provides three scenarios, tailored for Belgium, for every decade until 2100. In contrast, KNMI-ADC provides 191 scenarios, at a regional level and for two time horizons (near and far future). The suitability and practical applicability of CCI-HYDR and KNMI-ADC tools is particularly examined for a medium-sized catchment in Belgium. Since these two perturbation tools deliver stationary time-series, the pros and cons of such an approach are compared to an alternate one which produces transient time-series. The CCI-HYDR tool is found suitable for forcing computationally intensive detailed hydrological models, as it provides a limited number of contrasting scenarios representing the range of possible future climate conditions. The KNMI-ADC tool enables scanning a broader spectrum of climate scenarios (although less extreme than in the CCI-HYDR tool), which makes it suitable for forcing multiple runs of fast conceptual hydrological models. The approach based on the transient stochastic tool is particularly computationally demanding due to its stochastic nature and is therefore also not optimal for use in combination with a detailed distributed hydrological model.
    Keywords: rainfall perturbation; climate change scenarios; hydrological modelling.

  • Laboratory Investigation for development of local scour depth model for varying shapes of obstruction   Order a copy of this article
    by Mir Bintul Huda, Mohd Akbar Lone, Javaid Ahmad Bhat 
    Abstract: This paper reports the effect of the shape of obstruction on local scour depth. Laboratory experiments were conducted on a tilting glass flume to study scour phenomenon around five obstructions of different shapes. Obstructions studied were chosen keeping in view not only the bridge piers but also some other structures, like obstructions in the flow channels e.g. a jetty, big boulder, any building in the coastal area, etc. Maximum local equilibrium scour, a dependent parameter, was studied as a function of flow parameters and shape parameters of the obstruction. A model was developed for the maximum local scour depth estimation in which maximum local scour depth (ds) is a function of Froude number (Fr), flow depth (y) and shape factor (Sf). The experimental findings depict a considerable effect of the shape of obstruction on the local scour depth.
    Keywords: discharge; flow depth; Froude number; scour; local scour; obstructions; shapes.

  • Mining Industry Impacts on Surface Water Quality in South Part of Armenia   Order a copy of this article
    by Marine Nalbandyan 
    Abstract: This paper deals with the quality of water of one of the tributaries of the river Araks- River Voghchi and its watershed basin. This article covers an investigation of common ions (Ca, Mg, Na, Cl, K, SO4, HCO3) and HMs (Cu, Mo, Cr, Ni, Mn, Zn, Co, Cd, Pb, Ag, Hg, As ) in waters of the River Voghchi and its tributaries. The performed river water research was underpinned by monthly monitoring data for 2003-2011. The impact of pollution sources and water quality formation factors were indicated. Assessment of the river water pollution with common ions and HMs were carried out, and dominating elements were indicated. The paper is highlight pollution level of the river water for the period of unstable economy and period of their stabilization, giving the comparative analysis of river water pollution.
    Keywords: mining industry; river water pollution; heavy metals; common ions; statistics; correlation analysis; River Voghchi; Armenia.

  • Application of non-parametric regression in estimating missing daily rainfall data   Order a copy of this article
    by Rachel Makungo, John Odiyo 
    Abstract: Most daily rainfall time series data are too short and/or possess missing records hindering them to perform reliable and meaningful analyses. Robust locally weighted scatter smoother non-parametric regression approach (NPR), with tricube weighting function was used to estimate missing daily rainfall data in the upper reaches of Nzhelele and Luvuvhu River Catchments in Limpopo Province of South Africa. Though a number of methods have been developed and tested, the approach proposed in this study has not yet been widely applied for estimating missing rainfall data. Model performance was evaluated using mean bias error, correlation coefficient, coefficient of determination, root mean square error and Nash Sutcliffe coefficient of efficiency. Model performance ranged from acceptable to excellent. Graphical fits of observed and estimated rainfall data showed a general agreement. Scatter plots indicated that there was no definite pattern of underestimation and overestimation of peak rainfall events in both calibration and validation runs. Scatter points for low rainfall values (mostly between 0-25 mm) were closer to the best fit line showing good agreement between observed and simulated rainfall values for most of the stations. The study showed that NPR effectively estimated missing rainfall data.
    Keywords: catchment; missing rainfall data; model performance; non-parametric; regression; time series; tricube weighting function.

  • Farm dam siltation and sediment source tracing in the Zeerust - Swartruggens area in the North-West of South Africa   Order a copy of this article
    by Samuel Che Nde, Munyaradzi Manjoro, Manny Mathuthu 
    Abstract: Soil erosion and dam siltation are two serious environmental problems facing farmers in South Africa. The study aimed to assess farmers perceptions on dam siltation and strategies employed to address it, and to assess the potential of sediment source tracing in a farming area in the north-west region of South Africa. Most of the dams in the study area were severely affected by siltation and the most important strategy used to address the problem was regular mechanical removal of the accumulated sediment. In relation to sediment tracing, lead-210 (210Pb) was found to be a more effective tracer than caesium-137 (137Cs) for distinguishing between surface and subsurface sediment sources. On the other hand, magnetic susceptibility offered better distinction of the sediment sources than magnetic remanence. Mass balance modelling indicated that 100% of the sampled sediment dam 1 originated from surface sources. The results reflect the complexity of sediment mobilisation processes influenced by the nature and spatial distribution of rainfall and runoff connectivity in the catchments.
    Keywords: farm dam siltation; environmental radionuclides; environmental magnetism; sediment source tracing; mass balance modelling.
    DOI: 10.1504/IJHST.2019.10013030
     
  • Assessment of Future Groundwater Quality Using GIS for Bhimrad Area of Surat City (India)   Order a copy of this article
    by Manisha Desai, Jayantilal Patel 
    Abstract: Declination of water quality has become a global issue of concern as with the growth of human population, industrial and agricultural activities expand. Climate change threatens to cause major alterations in the hydrological cycle. The Bhimrad area of Surat city (Gujarat) is highly affected by ground water pollution because of its location in the vicinity of the industrial zone. There exists a creek adjoining Arabian Sea, in which all the wastewater of the city, including that of the industrial area is discharged, thus polluting land and other sources of water in the surrounding areas. The research paper shows the assessment of the groundwater quality degraded in the Bhimrad area of the Surat city on the basis of collection of past few year data of groundwater quality. Water quality has been assessed in term of the groundwater quality index (GWQI) by determining pH, Electric Conductivity, Total Dissolved Solids, Chlorine, Total Hardness, and Alkalinity in the premonsoon (May-June) and post monsoon (November-December) period for the years 2004, 2006, 2008, 2011, 2012, 2013, 2015. This research paper aims to analyze groundwater dilution used under the threat of pollution by identifying the prospects for improving the quality through artificial recharging that may impact groundwater quality. Calculation of percentage reduction in the groundwater quality parameters after recharging was carried out through which estimated improvement in GWQI using GIS, GWQI after recharging is analyzed for the years 2015 to 2050.
    Keywords: Sustainable Resources; Groundwater Quality; Water Conservation; GIS; Geological Information System.

  • Hydrological impacts of Climate Change on the Future Streamflow of Three Unregulated Catchments of the Australian Hydrologic Reference Stations   Order a copy of this article
    by Hashim Alsafi, Ranjan Sarukkalige 
    Abstract: A physically-based distributed hydrological model, the Block-wise use of the original TOPMODEL with the Muskingum-Cunge routing method (BTOPMC), is adopted to assess the impacts of future climate changes on the hydrological behaviour of three different sized contributing catchments of the Australian Hydrologic Reference Stations (HRSs); including Harvey River at Dingo-Road in Western Australia, Beardy River at Haystack and Goulburn River at Coggan in New South Wales. In this study, both historical and future modelled streamflow trends are compared and discussed. Firstly, the BTOPMC-model was calibrated and validated based on the observed hydro-meteorological data from the three contributing catchments. Then, the downscaled future climate signals from a multi-model ensemble of eight-GCMs of the CMIP5 under the RCP4.5 and RCP8.5 scenarios were used to force the calibrated BTOPMC-model to simulate the future daily streamflow at the three HRSs for the mid (2046-2065) and late (2080-2099) of the 21st-century. Nearly all GCMs predict a reduction tendencies in mean annual rainfall and an increase in temperature and potential evapotranspiration across the studied catchments. The mean annual streamflow measured at the three HRSs also shows reduction tendencies during the future periods under the two climate scenarios ranged between 26-53% at Dingo-Road HRS, 10-25% at Haystack-HRS and 6-33% at Coggan-HRS relative to the control run. The outcomes of this study are used to deliver valuable water management strategies to overcome the expected problem of water scarcity in the studied catchments.
    Keywords: Climate change; Hydrologic Reference Stations; physically-based simulation modelling; BTOPMC model; CMIP5; Australia.

  • Recent Approach in Producing Transparent Conductive Films (TCFs)   Order a copy of this article
    by Siavash Hosseinpour Chermahini, Kaveh Ostad-Ali-Askari 
    Abstract: Transparent conductive films (TCFs) are well known for their use in improving the efficiency of solar cell devices. The properties of transparent conductive materials are highly important due to their specifications and their influence on the performance of various devices. On the other hands, waste disposal is creating a global crisis which threaten the well-being of humans. Cheap electronic is one of the urgent current environmental problem. To this regards, different types of transparent conductive films have emerged, but indium tin oxide (ITO) and fluorine tin oxide (FTO) have been used in TCF sheets due to their optical transparency and electrical conductivity. However, some weaknesses, such a slow quality in the infrared region, the high cost of the elements, and their activity at low temperatures without the flexibility of transparency, have led to the search for a substitute. Moreover, TCFs need to be viable on a large scale for the next generation of optoelectronic devices as there is a lack of study in this area. Among all the candidates, a transparent hybrid of graphene and single-wall carbon nanotubes (SWCNTs) is a new trend in this area. Stable and homogeneous suspensions of GO sheets with strong hydrophilic and electrostatic repulsion properties are being used to produce TCFs. This trend has led to the creation of nanomaterials that exhibit better properties than their solo applications. Some techniques are able to increase the opt electrical properties with an additional transparency of more than 90%. Therefore, a comprehensive review was conducted for a new approach for the improvement of photovoltaic devices by means of a hybrid GP and SWCNT transparent conductive film.
    Keywords: Transparent conductive films (TCFs); single wall carbon nanotubes (SWCNTs); graphene oxide (GO); nanomaterial.

  • Estimating root zone soil moisture using multilayer feedforward neural networks based on Levenberg-Maquardt and scaled conjugate gradient algorithms   Order a copy of this article
    by John Odiyo, Rachel Makungo 
    Abstract: This paper presents the use of multilayer feedforward neural networks for root zone soil moisture estimation based on Levenberg-Maquardt (LM) and scaled conjugate gradient (SCG) algorithms. Data driven approaches such as artificial neural networks overcome some limitations of remote sensing, conceptual and semi-analytical models in root zone soil moisture estimation. This creates the need to compare neural networks training algorithms to determine those with best estimation accuracy. Observed volumetric soil moisture at 80 cm depth, rainfall and evaporation data were used to estimate soil moisture at 120 and 180 cm depths, within MATLAB. SCG trained network underestimated and/or overestimated soil moisture as compared to LM trained network. LM trained network has better performance and estimation accuracy. Estimated soil moisture is useful for irrigation scheduling, hydrological modelling, and groundwater recharge estimation in the study area.
    Keywords: algorithm; estimation accuracy; Levenberg-Maquardt; multilayer feedforward; neural networks; root zone; scaled conjugate gradient; soil moisture.

  • Prediction of discharge coefficient of combined weir-gate using ANN, ANFIS and SVM   Order a copy of this article
    by Abbas Parsaie, AmirHamzeh Haghiabi, Samad Emamgholizadeh, Hazi Mohammad Azamathulla 
    Abstract: Flow measurement is an important issue for developing the water conservation projects and evaluating the performance of irrigation and drainage networks. Weirs and gates are the most common structures which have been widely used for flow measurement. The main defects related them are deposition of suspended matter behind the weirs and accumulation of floating matter on water behind the gates, respectively. therefore, the weir-gate structure has been proposed to solve them infirmities. In this study, predicting the discharge coefficient of Weir-Gate was considered using the artificial neural network (ANN), support vector machine (SVM) and adaptive neuro-fuzzy inference systems (ANFIS). For this purpose, the related dataset were collected from the literature. Assessing the performance of three models show that all of them have suitable accuracy, however, the SVM model with a coefficient of determination (R2=0.94) and root mean square of error (RMSE=0.008) has the best performance in comparison with others. During the preparation of SVM it was found that the radial basic function as kernel function has best performance among the tested kernel functions. Sensitivity analysis of applied models showed that the ANN is the most sensitive model in comparison with others.
    Keywords: Flow Measurement; Hydraulic Efficiency; Irrigation and Drainage Networks; ANFIS.

  • DETERMINATION OF HYDRAULIC FEATURES IN COLOMBIAN RIVERS BY TRACER ANALYSIS   Order a copy of this article
    by Alfredo Constain, Carlos Peña, Duvan Mesa 
    Abstract: The importance of hydraulic, geomorphological and hydrodynamic conditions in rivers on watershed management cannot be overstated. However, in developing countries, sometimes the infrastructure is poor and these conditions are not managed properly. Therefore, this paper proposes a methodology to calculate flow, slope, Chezys C, Mannings n and hydrodynamic conditions in rivers with a tracer. This methodology allows the calculation of these hydraulic and hydrodynamic characteristics for rivers that have velocity from 0.108 m / s to 1.93 m/s.
    Keywords: Hydraulica features; hydrodynamic; rivers; tracer.

  • Selection of the Most Adequate Frequency Model to Estimate the Flood Extreme Values in the North west of Algeria   Order a copy of this article
    by Hebal Aziz 
    Abstract: This work is intended to determine the most appropriate model to estimate the extreme values of flood in the North West of Algeria. The study is conducted in two steps. The first one consists on the determination of the type of laws which may represents better the data series using the log-log plot. The second step extends on the establishment of a ranking of the laws of the selected type. This has become possible with the application of different choice criteria: the Bayesian Information Criterion, the Aka
    Keywords: Frequency model; North-west of Algeria; flood extreme values; Bayesian approach.

  • The application of Conceptual Modelling Approach to Evaluate the Impacts of Climate Change on the Future Streamflow in Three Unregulated Catchments of the Australian Hydrologic Reference Stations   Order a copy of this article
    by Hashim Alsafi, Ranjan Sarukkalige 
    Abstract: The future climate change impacts on streamflow variability at three selected contributing catchments of the Australian Hydrologic Reference Stations (HRSs), Harvey, Beardy and Goulburn catchments, are presented in this study. The HRSs network represents living gauges that enable the long-term streamflow monitoring and climate change adaptation. Observed hydro-meteorological data from the contributing catchments were used to calibrate and validate the Hydrologiska Byrans Vattenbalansavdelning (HBV) hydrological model before the streamflow prediction. The downscaled future rainfall and temperature from a multi-model ensemble of eight-Global Climate Models of the Coupled Model Inter-comparison Project phase 5 (CMIP5) under two Representative Concentration Pathways RCP4.5 and RCP8.5 were used to run the calibrated HBV model to simulate the future daily streamflow at the three HRSs. Nearly all GCMs predict reduction tendencies in mean annual rainfall and an increase in temperature and potential evaporation across the studied catchments during the mid (2046-2065) and late (2080-2099) of the 21st -century. The mean annual streamflow across the three catchments also tend to decrease during the future periods under the two climate scenarios and ranged between 31-60% for the Harvey catchment, 1- 24% for the Beardy catchment and 18-42% for the Goulburn catchment relative to the control run. The outcomes of this study could deliver valuable water management strategies to overcome the expected problem of water deficiency in the studied catchments.
    Keywords: Climate change; Hydrologic Reference Stations; conceptual modelling; HBV model; CMIP5; Australia.

  • Water Balance Study of a High Altitude Catchment in Indus Basin of Himalayas: Application of physics based distributed hydrologic model-MIKE SHE.   Order a copy of this article
    by Yasir Altaf, Manzoor Ahangar, Mohammad Fahimuddin 
    Abstract: The water balance of the Lidder basin was done by re-enacting all components of the hydrological cycle. MIKE SHE model was utilized to simulate all components of hydrological cycle of the Lidder basin. Water balance components were estimated at three sub-catchments Aru, Sheeshnag and at Akura and the model results show that ET losses at Aru, Sheeshnag, and Akura (total catchment) were to be 19.23 , 19.65 and 24.61 % of the total rainfall while runoff at Aru, Sheeshnag and Akura (total catchment) of Lidder basin were 34%, 40% and 57.02% of the total rainfall. Snowmelt contribution to the total streamflow in the Lidder River at Aru, Sheeshnag, and Akura (total catchment) was found to be 58.54, 54.19 and 41.75 %. The base flow contribution to the discharge in Lidder River at Aru, Sheeshnag, and Akura (total catchment) were estimated to be 22 %, 35 % and 43 % respectively. rnrn
    Keywords: Distributed Hydrological Model; Water Balance; Coupled Model.

  • Quantifying Soil Erodibility Parameters Due to Wastewater Chemicals   Order a copy of this article
    by Mohammed Abbas, Abdul-Sahib Al-Madhhachi, Sarah Esmael 
    Abstract: Many factories and hospitals dumped their wastewater into Tigris River without any treatment in Baghdad city. This could influence on soil erodibility on Tigris Riverbanks. Phenol, Nitrate, and Phosphate were considered as huge concentrations in wastewater chemicals. The main objectives of this research were: 1) to investigate the influence of three wastewater chemicals on erodibility parameters of cohesive soils using Blaisdells solution and scour depth solution techniques from jet erosion tests (JETs); 2) to develop relationship between erodibility parameters and soil hardness. An excess shear stress model was utilized to measure soil erodibility based on two empirical soil parameters: critical shear stress (c) and erodibility coefficient (kd). The results showed a constantly increased in kd for all three wastewater chemicals at different curing times and concentrations, while c values were decreased. An inverse relationship was developed between c and kd for both Blaisdells solution and scour depth solution techniques.
    Keywords: wastewater chemicals; soil erodibility parameters; polluted soils; jet erosion test; JET.
    DOI: 10.1504/IJHST.2019.10016884
     
  • The map-correlation method for ungauged catchments streamflow prediction in the Ufa River, Russian Federation   Order a copy of this article
    by Elena Belozerova, Nataliya Krasnogorskaya, Antonia Longobardi, Elvira Nafikova 
    Abstract: The paper investigates the problem of streamflow prediction at ungauged catchments by the use of the map correlation method and focuses on the selection of reference stream gauges to estimate the average daily streamflow for ungauged catchments. Daily streamflow data are indeed crucial for several fields such as water management, sustainable water resource management, hydropower energy production, but the number of ungauged watersheds is still big and reliable large scale regional approaches are indeed needed as a practical response to the ungauged catchment problem. In the following, results of an application to the catchments of the rivers Ufa and main tributaries for a total of 25 catchments, is presented. The map correlation method has been performed, where differences is made between the nearest stream gauge and the best correlated stream gauge criterion for reference station selection. It was found that, on average, for the case study the best performing method for the selection of reference station is the best correlated.
    Keywords: map correlation method; kriging; ungauged catchment prediction; reference stream gauge; Russian Federation.

  • Calibration of a Hydrological Model and Sensitivity Analysis of its Parameters: A Case Study of Seonath River Basin   Order a copy of this article
    by Mani Kant Verma, Mukesh Kumar Verma 
    Abstract: The objective of this paper is surface runoff estimation of the Seonath river basin using a semi-distributed hydrological model, i.e., SWAT (soil and water assessment tool). In this paper, the study on calibration and sensitivity is carried out using SWAT-CUP (calibration and uncertainty program) along with SUFI-2 (sequential uncertainty fitting algorithm). The performance of SWAT model is evaluated by various statistical measures; such as Nash-Sutcliffe coefficient (NS), coefficient of determination (R2), percent bias (Pbias), p factor, r factor and ratio of the root-mean-square error (RMSE) to the standard deviation of the observation (RSR). In the current work, 31 years (1980-2010) of weather data was used. The time slice for model calibration was 15 years, i.e., 1987 2001 with seven years of warming period 1980 1986 and validation period was comprised of 9 years (2002 2010). In the study, the calibration of the model was done for the two stations which is a major step for carrying out further study related to climate and land use change impact assessment. The study yielded satisfactory results in terms of model performance.
    Keywords: Hydrological modelling; Calibration; Sensitivity analysis; SWAT-CUP; SUFI-2.

  • Groundwater vulnerability Mapping of Jordanian phosphate mining area based on Phosphate concentration and GIS: Al-Abiad mine as a case study   Order a copy of this article
    by Adnan Al-Harahsheh, Majed Ibrahim, Noureddine Elboughdri, Mohammad Al-harahsheh, Salah Aljbour 
    Abstract: Groundwater constitutes the main water supply in Jordan. Therefore, various steps are taken to monitor groundwater quality and vulnerability for a sustainable groundwater development. The present study uses DRASTIC model on a national rate and assess the groundwater contamination by phosphate concentration released from the mining activities in south of Jordan (Al-Abiad area) using GIS environment. The DRASTIC index was used with seven parameters to describe physical characteristics of the aquifers. It is concluded that about 58.6% of the area was considered to be of moderate vulnerability, while high and low vulnerability were found to be at 0.6% and 42.8% respectively of the total area. On the other hand, investigation of infiltration process of selected pollutants (Soluble phosphate and chloride ions) through the surface layer of study area is concluded the vulnerability of the groundwater quality toward such as pollutants. These pollutants are detected in washing water effluent of phosphate beneficiation process. Chemical Analysis of the used washing water shows high concentration of P2O5(TCP) , Cl- and SiO2 comparing with initial feed water. To get rid of waste water streams, the current practice in at Al-Abiad and other Jordanian phosphate mining industry is to send it to desert without any attempt to treat and recycle this water. Therefore, urgent pollution prevention measures should be considered for such mining activities within the whole of Jordanian phosphate mining area .
    Keywords: Vulnerability; Waste water; Groundwater; DRASTIC; Phosphate; GIS.

  • Hydrochemistry and water quality index (WQI)application in the assessment of groundwater quality in Oyo State, Nigeria.   Order a copy of this article
    by Timothy O. Ogunbode, Omowumi T. Akinola 
    Abstract: Groundwater quality assessment and the application of WQI in Oyo State, Nigeria were studied. Twenty five of the 33 LGAs in the State were selected while five villages were randomly selected from each for this purpose. Samples were collected from each of the villages and analysed. The results revealed that the groundwater is generally fit for human consumption by World Health Organisation standard. Weighted average water quality index analysis showed that the groundwater in the 24 LGAs fell in the excellent water while one fell in the good water category indicating its potability. Multivariate analysis showed that four pairs of water quality variables (EC and TDS, EC and NO3, TDS and NO3, Na+ and K+) have positive correlations. Only EC and TDS correlate positively with WQI results and so positively influenced WQ analysis results. Regular investigation is recommended for the optimal relevance of WQI in water quality management.
    Keywords: water quality index; WQI; groundwater; Oyo State; correlation; hydrochemistry; WQI mapping; Nigeria.
    DOI: 10.1504/IJHST.2019.10013356
     
  • The long-term trends in hydro-climatology of the Dinder and Rahad basins, Blue Nile, Ethiopia/Sudan   Order a copy of this article
    by Khalid Hassaballah, Yasir Mohamed, Stefan Uhlenbrook 
    Abstract: This paper examines the long-term trends of streamflow, rainfall, and temperature over the Dinder and Rahad River basins. Streamflow of the Rahad River showed significant increasing trends in both the annual and seasonal flows. There was no detectable change in the mean annual and seasonal flow patterns of the Dinder. However, the analysis of seasonal maxima suggested a shift towards decreased flows during the high flow period (August) and increased flows during the low flow period (November). The Dinder maxima of August decreased from 517 m3/s over the early part of the record (1972-1991) to 396 m3/s over the latest years (1992-2011). The mean annual temperature showed significant increasing trends at the rate of 0.24 and 0.30 oC/decade in the examined stations. Rainfall showed no significant change. The result of this study suggests other factors than climate variability (e.g. land use land cover changes) to be responsible for streamflow alterations.
    Keywords: Time series analysis; Hydro-climatic trend; Dinder and Rahad basin; Mann–Kendall; Pettitt test; IHA; non-parametric analysis.

  • Assessment of heavy metals in surface water of Vishwamitri river   Order a copy of this article
    by Pranavkumar Bhangaonkar, Jayeshkumar Patel 
    Abstract: Heavy metal analysis of the surface waters from Vishwamitri River was conducted in pre-monsoon, monsoon and post-monsoon seasons during year 20152016. Samples were collected and analysed from various sampling stations along the Vishwamitri with a view to assess and analyse the concentration of various metals, i.e., Cd, Cu, Fe, Pb, Mn, Hg, Ni and Zn. The overall mean concentration revealed the toxicity level of heavy metals in the following order Pb>Fe>Hg>Cd>Ni>Cu>Mn>Zn. pH values were observed less than seven and consequently concentrations of most of the heavy metals were observed high in downstream stretch. Identification of point and non-point sources of heavy metal pollution in Vishwamitri is necessary. Suitability of Vishwamitri water is to be assessed for drinking purposes. Assessment regarding the biotoxic effects of heavy metals concentration and adoption of appropriate treatments and controlling measures to reduce metallurgical effluent load deposited into the river is need of the hour.
    Keywords: heavy metals; monsoon; post-monsoon; pre-monsoon; surface water; Vishwamitri; water quality.
    DOI: 10.1504/IJHST.2019.10017535
     
  • ASSESSMENT OF MODIFIED CURVE NUMBER METHOD BY EVALUATION OF RUNOFF DEPTH IN SULAK BASIN-IRAQ   Order a copy of this article
    by GHASSAN AL-DULAIMI 
    Abstract: Traditional hydrological analysis used maps and ground survey as tools to obtain the basic parameters of the watershed. However, for large catchment area the above criteria are both costly and time consuming. In this research a hydrological model modified natural resources conservation service curve number (NRCS-CN) & Geographical Information System GIS technique are used together to obtain the runoff depth for Sulak catchment area that located in the northern western part of Iraq. The basin divided into three sub-basins, runoff has been estimate for each sub-basin by three approaches. The research detect that the slope parameter affects runoff estimation significantly also its found that for each sub-watershed runoff varies drastically from sub-watershed to sub-watershed of Sulak basin. The analysis of variance test showed that there was significant difference between each curve number value for each sub-watershed, accordingly runoff calculated by Williams method gives valves above the average comparing with other methods . Total runoff estimated by three approaches for entire catchment area which shows that around 51% of total runoff is generated in months January and February, That because of heavy rainfall and high soil moisture content (Antecedent Moisture Content AMC-III) during that period.
    Keywords: Sulak Catchment area; Runoff,Modified Curve Number Method; GIS Technique.

  • Impact of Potential Evapotranspiration on Maize yields in Northern Cameroon using Aquacrop Model   Order a copy of this article
    by Brice B.S. Wandjie, Andre LENOUO, David Monkam 
    Abstract: This work presents impact of potential evapotranspiration (PET) on the agricultural yield of maize in Northern Cameroon using the AquaCrop model. Weather variables, rainfall, temperature, wind, solar radiation, water vapor pressure, relative humidity in three (03) towns in Northern Cameroon, located in Central Africa are used as independent variables in estimating five (05) PET models from 1985 to 2004 in two of these towns and from 1985 to 1995 in the other. After comparing different PET models, AquaCrop model, which is a crop, culture simulation software developed by the Food and Agriculture Organization (FAO) has been calibrated to simulate maize yields during the period of June 15 to October 24. The results indicated that maize yields increased with PET methods values in the whole study zones for each year. In fact, this study revealed that, compared to the results given using reference PET (FAO Penman-Monteith) values, maize yields raised until up to 60% for the PET values greater than reference PET in the different towns.
    Keywords: Potential evapotranspiration; AquaCrop; Central Africa; Maize yields.

  • A SIMPLE AND EFFICIENT NUMERICAL MODEL FOR SIMULATING ONE DIMENSIONAL DAM BREAK FLOWS   Order a copy of this article
    by Hriday Mani Kalita 
    Abstract: A semi implicit finite difference scheme is presented in this paper for simulation of dam break flow over undulated bed. For this purpose, the one dimensional (1D) governing equations of shallow water flow, in a deviatoric version is solved here. One of the main important features of the present model is that, no special treatment is required here to deal with the offending friction slope source term for very less water depth. Regarding the bed slope term also, simple central difference approximation is sufficient to handle undulated channel bed. To investigate the performance of the present model in diverse situations, it is used to replicate different dam break test problems including one of known analytical solution and two experimental dam break cases. A detail analysis of the results show that the model capable is of producing good quality results for varied conditions. A sensitivity analysis is carried out for the damping parameter and an optimal range is proposed for it.
    Keywords: Shallow water equations; dam break flow; wetting and drying; irregular topography.

  • Hydrological model parameters space during calibration   Order a copy of this article
    by Shailesh Kumar Singh 
    Abstract: Hydrological models are widely used for different water resource problems. Hence, the same model can have different purpose. Depending on the purpose of the model, it need to be calibrated differently. There are several objective functions which can be use to calibrate a model, but there is not a single objective function which can describe all the components of a hydrograph simultaneously. In this study, an attempt has been made to analysis the parameter space mapped by different objective functions during calibration of a hydrological model. A conceptual hydrological model HYMOD was calibrated using Robust Parameter Estimation (ROPE) algorithm with different objective functions, namely Nash-Sutcliff coefficient, root mean square error, volume error and peak error. Also with log Nash-Sutcliff coefficient, log root mean square error, log volume error and log peak error. It has been found that the different objective function have mapped parameter spaces differently. Details diagnosis of parameter space reveal that there is no common intersection of parameter space obtained by different objective functions. The volume shrinkage of parameter space by different objective functions during parameter searching iteration are different. Which indicate optimal parameter set obtained by different objective functions are at different rate. The diagnosis of parameter space has lead us to develop a Hierarchical Optimization (HOP) calibration technique. In HOP calibration, firstly the search domain are constrain using one objective function which is general in nature and gives importance to over all characteristics of hydrograph. In second iteration it further constrain the space using another function. This process is repeated until dynamics of the hydrograph are well represented. HOP based calibration outperformed any calibration based on single objective function calibration. The result of this study will be helpful for robust parameterization of hydrological model and to obtain a global parameter which can be better represent ion of all component of hydrograph.
    Keywords: ROPE algorithm; conceptual hydrological model; objective function; HYMOD.

  • Evaluation of multiple satellite-derived rainfall products over Morocco   Order a copy of this article
    by FOUAD GADOUALI, MOHAMED MESSOULI 
    Abstract: The focus of this study is to assess the accuracy of four satellite-based rainfall estimations in Morocco. Tropical Rainfall Measuring Mission, version 7 (TRMM3B42V7), African Rainfall Climatology, version 2 (ARC2), African Rainfall Estimation Algorithm, version 2 (RFE2.0) and Precipitation Estimation From Remote Sensing Information using Artificial Neural Network-Climate Data Center (PERSIANN-CDR) are evaluated with observations from 19 meteorological stations over Morocco, at daily and monthly time steps for the period 2001-2014. In order to study the performance dependency of these satellite products on topography and climate types, evaluation is carried out at different seasons as well as different classes of topography. Results show that, all the satellite datasets reasonably reproduce the mean annual rainfall and the seasonal cycle over all the studied area. In terms of rainfall day statistics, ARC2 and RFE2.0 have performed the best while PERSIANN-CDR exhibited the worst performance. Categorical statistical indices obtained for different seasons and elevation classes showed that the TRMM3B42V7 product outperforms others in both the boreal summer (JJA) and the rain shadow areas. For the total precipitation, all the products underestimate rainfall amount in low and mid elevation, whereas a marked overestimation is observed over the rain shadow areas. Comparison between monthly and daily scores confirmed the improvement of the satellite products performance when using the monthly step. In terms of rainfall intensity, TRMM3B42V7 exhibits good performance to reproduce high rainfall intensities, which makes this product suitable on the monitoring of floods that are mainly caused by heavy rainfall. However, the shortcomings presented by all the satellite rainfall products, especially at the daily step, could be useful for their improvements and point out to the need for applying bias adjustments before using them.
    Keywords: TRMM; ARC2; RFE2.0; PERSIANN; Satellite rainfall; Morocco; Precipitation.

  • Potential of Roundabout as a Stormwater Detention Basin in Equatorial Region   Order a copy of this article
    by Loh Siew Ling, Mah Darrien Yau Seng 
    Abstract: From the past experiences, flooding created large infrastructure problems for the city and a huge economic loss together with the damages of existing properties and goods. Therefore, this study was performed to investigate the potential of roundabout acting as a detention basin to relieve flash flood problems in equatorial region. With the aid of USEPA SWMM 5.0, rainfall-runoff simulation for existing drainage system was computed. Then, a stormwater detention basin was added to the system. As a result, Stutong roundabout in Kuching City with a basin depth of 1.2 m was capable of holding 100% of running water from the contributing catchment area. The methods implied that the size and depth of detention basin limited by the space of the Stutong roundabout were the main parameters that should be figured out first. Then, the contributing catchments allowed to be drained to the detention basin could be related.
    Keywords: Dry Pond; Runoff; Storm Water Management Model (SWMM); Urban Stormwater Management.

  • Design Criteria of Protective Filters Based on Particle Shape and Gradation Parameters   Order a copy of this article
    by Nasir Ahmad Rather, Mohd Akbar Lone, Abdul Qayoom Dar, Saeid Eslamian, Bintul Huda Mir, Bilal Ahmad Dar 
    Abstract: This study presents design criteria of protective filters for different shapes of filter material and subsequently the effect of shape parameters of filter particles on its design. The filter-base combination tests have been conducted in the laboratory for different shapes of filter material i.e., elliptical, sub-rounded, irregular and elongated. The shape parameters considered in the study are sphericity, shape factor, flatness ratio and elongation ratio. It was observed that the design criteria varied with the shape of filter particles even if the gradation of the filter material was similar. The design criteria in the form of empirical equations have been developed on the basis of D15 of filter mass, d85 of base, permeability (k) of filter mass and shape parameters of filter mass.
    Keywords: filter; shape; sphericity; shape factor; design criteria; permeability; gradation.

  • Optimum use of groundwater to plan new cropping pattern for Sinnar, MS, India   Order a copy of this article
    by Jayantilal Patel, Smita Varade 
    Abstract: In todays world conservation, management of water resources and land are major concerns. The paper presents an application of LINGO software and Particle Swarm Optimization (PSO) algorithm to determine optimal cropping pattern for Sinnar, MS, India. The optimization model is developed and solved using LINGO and PSO for maximization of net benefits. In existing cropping pattern net benefit are 1101.15 million Rs. whereas obtained by LINGO and PSO are 1461.2 million Rs. and 1466.3 million Rs. respectively. Net benefits obtained using PSO are better than LINGO. Hence cropping pattern obtained from PSO is suggested as proposed cropping pattern for study area.
    Keywords: Optimization; LINGO; PSO; Optimal cropping pattern.

  • Evaluation of Uncertainty in Evapotranspiration Values by FAO56-Penman-Monteith&Hargreaves-Samani Methods   Order a copy of this article
    by Hossein Talebmorad, Abdollah Ahmadnejad, Saeid Eslamian, Kaveh Ostad-Ali-Askari, Vijay P. Singh 
    Abstract: Methods of calculating evapotranspiration are subject to uncertainty. Since the results of these methods are used for planning and design of irrigation systems, it is important to evaluate their uncertainty. Using 54 years of data, this study evaluated the uncertainty values of monthly reference crop evapotranspiration calculated with the FAO-56 Penman- Monteith and Hargreaves-Samani methods. The values of reference evapotranspiration were calculated by the ETo Calculator and for uncertainty analysis SPLUS2000 and Bootstrap test was used. The objective of this study was to determine the range of variation in the results of each method. It was found that for both methods, the bandwidth uncertainty obtained with 95% confidence interval was more in warm months than in cold months, and the mean and variance by the Hargreaves-Samani method were always less than by the FAO-56 Penman-Monteith method. The minimum and maximum bandwidth values of average uncertainty were 0.094 and 0.203, and the minimum and maximum bandwidth values of variance uncertainty were 0.029 and 0.083, respectively, in December and May for the Hargreaves-Samani method. The minimum and maximum bandwidth values of average uncertainty were 0.12 and 0.414, and the minimum and maximum bandwidth values of variance uncertainty were 0.039 and 0.44, respectively in December and July for the FAO-56 Penman-Monteith method. The uncertainty value of the FAO-56 Penman-Monteith method was more than of the Hargreaves-Samani method, because the number of parameters used in the FAO-56 method was more than in Hargreaves-Samani method which increased uncertainty resources.
    Keywords: Bootstrap; FAO-Penman-Monteith; Hargreaves-Samani; Uncertainty.

  • Assessment of Climate change parameters impact on long-term sediment transport trend Case study; Azam River basin   Order a copy of this article
    by Mehdi Yazdian, Sara Nazari 
    Abstract: At the turn of the new decade, climate change is one of the key issues that has affected all social, economic and other humans activities. In this study, the effects of changes in precipitation and temperature parameters on sediment changes in the Azam River located in Yazd province of Iran were investigated. The Mann-Kendall test was used to identify the changes in sediment parameters. Subsequently, in order to predict the sediment changes the artificial neural network (ANN) was considered. In order to use the ANN model for predicting the sediment amount, firstly, the model was trained by temperature and precipitation data as input parameters, in the next step the ANN model sensitivity analysis was done by changing the layers and the neuron numbers, finally the most suitable model with 25 layers and 30 neurons was chosen. The final trained ANN model was used forecasting the sediment amount over 20152044.
    Keywords: climate change; sediment; Azam River basin; Mann-Kendall test; artificial neural network; ANN.
    DOI: 10.1504/IJHST.2020.10016148
     
  • Corrosion and Deposition in Karoon River, Iran, Based on Hydrometric Stations   Order a copy of this article
    by Mehdi Derakhshan Nia, Shahab Dalvand, Behrouz Asakereh, Kaveh Ostad-Ali-Askari 
    Abstract: Water quality is as important as its quantity. Water in nature often has impurities that prevent the use of this vital substance. For this reason, different indicators are presented for the detection and elimination of impurities in the water. In this paper, the chemical parameters of the Karun River (within the Ahwaz-Mollasani) have been investigated in order to determine the corrosion or sedimentation in the irrigation system under pressure.For this purpose, two Ryznarand Langelierindicators have been used and after the necessary calculations it has been determined that the river water has a negative Langelierindex (LSI<0) and a high Ryznarindex(RSI>8.5) during the specified time interval, indicating high acidity during this time period, which causes deterioration and decay in Marine structures (Especially low pH areas)
    Keywords: corrosion; deposition,Langelierand Ryznarindexes; Karoonriver.

  • The Analysis of the Most Important Climatic Parameters Affecting Performance of Crop Variability in a Changing Climate   Order a copy of this article
    by Safieh Javadinejad, Saeid Eslamian, Kaveh Ostad-Ali-Askari 
    Abstract: Projecting crop yield, under future climate plays a vital role in planning for supply and demand, especially in arid and semi-arid regions. Changes in climate can influence crop yields due to varying evapotranspiration and precipitation over agricultural regions. In Zayandeh Rud river basin, agriculture is extensive and the crop production such as rice, potato, wheat and barley are important for the income generation and food security. The rice and potato are sensitive to variations in temperature and rainfall patterns, the present study was undertaken to assess the impact of climate change on these crop yields. Climate data were generated from 17 meteorological stations. Historical climate data from 1971-2005 were used as input to CROPWAT model to analyze the potential and actual evapotranspiration that affects crop yields. Furthermore, the generated local climatic data of future years (2006-2040), (2041-2075) and (2076-2100) under the severest scenario (RCP 8.5) from CMIP5 climate model are selected. Then the data were downscaled statistically and were inputted to the CROPWAT to determine the changes in ETo , Eta and crop yield from the baseline period. The results indicate that all crops shows increasing water requirement in the future period. These maps enable us to generate the appropriate adaptation measures and best management practices under future climate change scenarios. The result of this research paper makes a significant contribution to climate smart agriculture in Isfahan- Iran. For example, agricultural development practitioners can devise the effective policies and planning to decrease the vulnerability to climate alteration impacts.
    Keywords: Climate change; evapotranspiration; CROPWAT; crop yield; Zayandeh Rud.

  • Potential Implications of Land Use/Land Cover Change and Climate Variability on Ungauged Watershed Hydrology   Order a copy of this article
    by Afera Halefom, Asirat Teshome, Ermias Sisay 
    Abstract: In Farta Watershed, the impact of land use/land cover (LULC) change and climate variability on hydrological processes was assessed and simulated using SWAT. The trends on hydro climatic variables were analyzed in the study watershed by using Mann-Kendall test. Then the model performance was assessed with the use of statistical indicators like coefficient of determination (R2), Nash-Sutcliffe model efficiency (NSE), the ratio of root mean square error (RSR), and percentage bias (PBIAS). The values were 0.79, 0.67, 0.82, and 4.8% throughout calibration and 0.61, 0.69, 0.69, and 5.2% throughout validation, respectively. The areal extent of each land use land cover for 17 years of span (2000 to 2017) based on five categories were 9.2 Km2 urban, 8.5 Km2 plantations, 5.7 Km2 water body, -22.3 Km2 agricultural land and -1.0 Km2 pastureland. Percentage change of 10.94%, 8.13% and 16.09% for a significant increasing movement of average annual temperature, mean maximum temperature and mean minimum temperature were observed respectively. Substantial increasing inclinations were observed in seasonal and average precipitation for the ungauged watershed. Hence, this study endorses that the above aspects should be taken into consideration for water resources planning and management in the study area, South Gondar, Ethiopia.
    Keywords: Farta watershed; ungauged; LULC; Temperature; precipitation.

  • LANDUSE CHANGE AND SEDIMENT YIELD IN AN URBANIZED TROPICAL DELTAIC CATCHMENT IN PORT HARCOURT, SOUTH-SOUTH OF NIGERIA   Order a copy of this article
    by IFEANYICHUKWU EZEKWE, Michael Ulu Kalu ANYA 
    Abstract: River channel blockage due to high siltation is common in most urbanized catchments, leading to frequent flooding experiences. This is the case in the Woji River Basin. This study set out to investigate the changing landuse characteristics in the Woji River basin and its effect on the river channel dynamics and sediment yield. Channel morphometry was determined from remotely sensed data and correlationship was measured using the Spearman Ranks and Pearsons Product Moment co relational statistics. The result showed high influence of urban processes / landuse change on the River sediment yield, channel discharge regimes and channel morphometry characteristics. Other secondary effects of urbanization on the river dynamics found include; urban encroachment into the floodplains, deposition of wastes into the river course and high runoff occasioned by increasing basin surface imperviousness culminating in downstream flooding events. Treatment of river channel and headstream wetlands protection was among recommendations.
    Keywords: Channel dynamics; Landuse; Sediment Yield; Urbanization; Woji River.

  • Quantifying Tigris Riverbanks Stability of Southeast Baghdad City using BSTEM   Order a copy of this article
    by Abdul-Sahib Al-Madhhachi, Haider Al-Mussawy, Mohammed Basheer, Ali Abdul-Sahib 
    Abstract: A huge retreat on Tigris Riverbanks of Numaniyah-Kut reach was recently investigated in southeast Baghdad, Iraq. Riverbank retreat due to both fluvial erosion and geotechnical failure was recently predicted from Bank Stability and Toe Erosion Model (BSTEM). The goal of this paper was to compute Tigris riverbanks stability for three sites (A, B, and C) along Numaniyah-Kut reach using BSTEM with two different scenarios. The first scenario was assumed that the bank layers were varied by three different soil moisture contents. The second scenario was assumed that the whole bank was varied by three different soil moisture contents. Field measurements were performed along Numaniyah-Kut reach included; soil samples, river cross section surveys, and hydrological measurements. Specimens acquired from the sites were laboratory tests to obtain geotechnical and fluvial parameters in order to apply the two scenarios. Dry and optimum soil moisture contents obtained more erodible banks compared to wet banks. The results also showed that both scenarios indicated that sites B and C were more erodible compared to site A. In general, banks are more erodible and more unstable at downstream of Numaniyah city in compared with upstream of Kut barrage.
    Keywords: BSTEM; Tigris Riverbanks Stability; Riverbanks Erosion; Numaniyah-Kut reach.

  • Modelling runoff in a river basin, India: An integration for developing un-gauged catchment   Order a copy of this article
    by Sandeep Samantaray, Dillip K. Ghose 
    Abstract: Stagerunoff model based on non linear multilayer regression (NLMR) and Artificial Neural Networks (ANNs) are developed in the present study. Models are developed using collected dataset in short term basis during monsoon. The results confirmed that Back Propagation neural Network (BPNN) model is an important alternative to regression models. BPNN are developed using extended gradient descent based delta-learning algorithm and Radial Basis Function Network (RBFN) are developed using Gaussian potential functions. Predicted results using BPNN and RBFN model perform better as compared to NLMR and BPNN is found to be the best among all three techniques. The results of this work are integration for measuring runoff in un-gauged catchment approaching to the river basin.
    Keywords: artificial neural network; regression; River basin; runoff; stage.

  • Revisiting Maximum Observed Precipitation and Discharge Envelope Curves   Order a copy of this article
    by Mohammad Zakwan 
    Abstract: Hydrologists and Hydraulic Engineers often require data of greatest observed point rainfall or maximum observed discharge which may occur in a river basin in order to reduce the probability of failure of large hydraulic structures. Often the envelope curves are used to estimate the extreme precipitation and floods. In the present study revised envelope curve equations have been developed for World maximum point rainfall and maximum flood in a river basin. The equations developed in the present study were found to fit the data better than previous equations. Separate equation was developed to correlate maximum observed discharge to basin area for Indian rivers.
    Keywords: Maximum; Rainfall; Discharge; World; India.

  • The Influence of Particle Shape and Gradation Parameters on the Permeability of Filter Media   Order a copy of this article
    by Nasir Ahmad Rather, Mohd Akbar Lone, Abdul Qayoom Dar 
    Abstract: In the present study, an effort has been made to determine the effect of shape of filter media particles and their gradation on its permeability. Six different shapes of the graded filter particles, ranging from rounded to flat, were used in the study. Experiments were carried out to assess the variation of permeability with respect to the various shape parameters, viz. sphericity, roundness, shape factor, flatness ratio, elongation ratio, angularity index and the gradation parameters, for each group of the material. A model on the basis of experimental data, obtained in the study was developed which takes into account the variation of the above mentioned shape and gradation parameters for estimation of the permeability through filter media.
    Keywords: filter; permeability; shape parameters; gradation; particles; sphericity; roundness; elongation ratio; angularity.

  • Probabilistic Estimation of Design Runoff Curve Number: A Case Study for Shakkar River Watershed, India   Order a copy of this article
    by Sarita Gajbhiye Meshram, Chandrashekhar Meshram 
    Abstract: In this study, One-day, Two-day and Three-day maximum surface runoff were calculated. The curve number (CN) are dealt with as arbitrary factors with the CN connected with antecedent moisture condition (AMC-II) representing 50%, AMC-I, AMC-III representative of 10% and 90 % CN value respectively. The maximum surface runoff for 1, 2 and 3 day was fitted with three probability distribution (Log-normal, Gumble and Log Pearson-III). Out of three probability distribution, Log Pearson-III showed the best fit for the data. The maximum surface runoff (1/2/3 day) was estimated at 2, 5, 10, 25, 50, 100 and 200 years return periods. For all the return periods and rain durations, the design CN runoff and conventional design runoff found satisfactory performance. Probalistic estimation of 1, 2 & 3 day maximum runoff is important for safe and cost effective planning and design of surface runoff storage system.
    Keywords: Design Curve number; Probability distribution; Watershed; SCS-CN.

  • Leaching of organic material in polymeric pipes distributing desalinated water   Order a copy of this article
    by Kazi Fattah, Md. Maruf Mortula 
    Abstract: Polymeric pipes have now become a favourite choice for water distribution networks. However, the role of polymeric pipes with respect to quality of water distributed has not been extensively studied. These studies are critical for desalinated water distribution as the water can be aggressive to its surroundings. The objective of this study was to identify the leaching of organic carbon from three different polymeric pipes; polyvinyl chloride (PVC), polypropylene (PPR) and polyethylene (PE). The study investigated the role of pH and residual chlorine concentrations on the leaching of organic carbon. Laboratory-based pipe loop systems using desalinated water was used to investigate the leaching of organic matter. The results revealed that the migration of organic material was in the order of PE>PPR>PVC. Results indicated the lowest level of potential precursors of disinfection by-products was present in PVC pipes, compared to PPR and PE pipes.
    Keywords: water distribution system; polymeric pipes; desalinated water; leaching; organic material.

  • Flood risk assessment and management in urban areas: a case study in Bechar City, Southwestern Algeria   Order a copy of this article
    by BOUHELLALA Kherfia, Cherif El-Amine 
    Abstract: Flood has always been considered as one of the natural catastrophes that accompanies with huge losses and damages, which affect the lives of human beings. The present paper presents a flood risk assessment approach for Bechar city, an urban area in Southwest of Algeria using hydrologic engineering centres-river analysis system (HEC-RAS). In order to achieve better floodplain management in the study area, a suite of solutions were developed, taking into account hydraulic, infrastructure, environmental, geomorphic, economic and social considerations. Some of the key solutions identified included: 1) redevelopment of the Bechar Wadi over the entire urbanised area, on a width of the bed of the Wadi whose sizing will be ensured by a detailed study; 2) evacuation of excess flow through a bypass channel to Tigheline Wadi; 3) establishment of a dam in downstream of El Abiad Wadi. The results of this study will be of great help to the decision makers in the field of floodplain management, especially the involved governments department, to make a proper plan for future development.
    Keywords: Bechar Wadi; Floodplain management; Flood risk assessment; Southwest of Algeria; Urban area.

  • Interbasin water transfer conflicts. The case of the Tagus-Segura Aqueduct (Spain)   Order a copy of this article
    by Alvaro Morote, Maria Hernandez, Antonio-Manuel Rico, Saeid Eslamian 
    Abstract: Since its inauguration in 1979, the Tagus-Segura Aqueduct has become one of the hydraulic infrastructures that have given rise to the highest number of inter-regional conflicts in Spain during recent decades. The aim of this paper is to analyse the political, social, environmental and economic conflicts presented in the donor (Tagus) and recipient (Segura) basins of this infrastructure. To this end, through the holding of interviews with the main stakeholders and an analysis of the regulations, an assessment has been made of the results (for and against) of those who defend maintaining this infrastructure, owing to its far-reaching social and economic impact, and those who advocate its immediate or progressive closure. In conclusion, the case analysed here has become one of the foremost inter-regional water conflicts in Spain which, currently, after the proposal and adoption of certain regulatory measures, continues to represent a conflict over water use that may be of interest and comparison in the international scope.
    Keywords: Transfers; conflicts; water; Tagus-Segura Aqueduct; Spain.

  • Climate Change Impact on Groundwater Recharge of Umm ER Raduma Unconfined Aquifer Western Desert, Iraq   Order a copy of this article
    by Waqed Hassan 
    Abstract: The impact of future climate change on groundwater resources is significant, especially for arid and semi-arid areas such as the Middle East. However, little interest has been shown in climate change phenomena, despite its effect in this region. In this study, the effect of climate change on groundwater recharge in the Umm Er Radhuma unconfined aquifer in the Western Desert, Iraq was simulated using a modeling approach (WetSpass). Climate variables predicted for the period 2020 to 2099, were generated from the Hadley Center for Climate Prediction and Research (HadCM3), these appropriate for the most important developments in emission scenarios A2 and B2, in 7 selected meteorology stations throughout the study area. The downscale of precipitation, temperature (maximum and minimum) and wind speed were added to the groundwater recharge model to predict future recharge. The results indicated an increase in annual precipitation and in average temperature for the two selected scenarios. For the study area region, precipitation is predicted to increase by 5.4% and 3.19%, for A2 and B2 scenarios, respectively. The average temperature is also predicted to increase by 0.51-1.01
    Keywords: Water resources management; Groundwater sustainability; Climate change; Wetspass; Umm Er Radhuma aquifer.

  • A review on Hydrological Region Homogeneity   Order a copy of this article
    by Safieh Javadinejad, Kaveh Ostad-Ali-Askari, Maryam Marani-Barzani 
    Abstract: Hydrologic classification is the procedure of systematically ordering streams, rivers or catchments into groups that are most similar with regard to features of their flow regime and applied to identify hydrologically homogenous regions. Previous homogeneousattempts have depend on a plethora of hydrologic metrics that considerfeatures of flow changeability that are assumed to be significant in shaping physical processes in catchments. This researchexplain the methods of hydrological homogeneity by reviewing past and existing approaches (usually statistical techniques) and also provide a methodological framework for hydrological homogeneity that depicts critical components of the classification process.
    Keywords: Hydrologic classification; Homogeneous; Similarity; Physical processes; Classification process.

  • Statistical and Trend Analyses of long-term rainfall data: A case study for Mauritius   Order a copy of this article
    by Reena Seebocus, Michel Roddy Lollchund, Miloud Bessafi 
    Abstract: This paper focuses on the analysis of monthly mean rainfall data for the period 1950-2016 for Mauritius using statistical techniques and decomposition method. For the statistical analysis, the data are fitted to commonly used probability distribution function for which parameters are estimated using the Method of Maximum Likelihood Estimation (MLE). The Anderson-Darling (A-D), Kolmogorov-Smirnov (K-S) and Chi Square (C-S) tests are then employed to determine which PDF best fits the data. The results obtained indicate that the Log-Normal, GEV and Inverse Gaussian PDFs best fit the rainfall data at less than 5% significance level. The Ensemble Empirical Mode Decomposition (EEMD) method is employed to study the trends in the data. Results obtained are in terms of Intrinsic Mode Functions (IMFs) and the trendline. The analysis reveals that there is a general linear decrease of 1 mm/year in the amount of rainfall.
    Keywords: Rainfall; Statistical techniques; Probability Distribution Function; Goodness-of-fit tests; Ensemble Empirical Mode Decomposition (EEMD).

  • DAILY DISCHARGE SIMULATION: COMBINING SEMI-DISTRIBUTED GIS-BASED AND ARTIFICIAL INTELLIGENCE MODELS   Order a copy of this article
    by Ali Suliman, Ayob Katimon, Intan Zaurah Mat Darus 
    Abstract: Developing highly accurate semi-distributed rainfall runoff models are still a big challenge in streamflow simulation. In this paper, a new technique using ANN to improve the accuracy of TOPMODEL which contains three sub-models is presented. A medium catchment located in tropical Malaysia is used. The proposed scheme is to replace one of the sub-models by Artificial Intelligence models. Model results are evaluated by Nash-Sutcliffe model (NS), and correlation coefficient (CoC) which demonstrate the ability of ANN to improve the accuracy of TOPMODEL. It is concluded that the scheme can improve performance in terms of streamflow simulation. Best performance is obtained by the replacement of one sub-model, which, although not as accurate, allowed for the retention of a certain degree of physical representation.
    Keywords: TOPMODEL-Simulink; Johor River Basin; Hybrid; ANN; MLP; Artificial Intelligence; Tropical Catchment; Rantau Panjang; Rainfall Runoff Models; Malaysia.

  • Assessment of meteorological and hydrological drought; a case study in Kirindi Oya River basin in Sri Lanka   Order a copy of this article
    by Nimal Abeysingha, M.G. Wickramasuriya, Janakee Meegastenna 
    Abstract: A desk study was conducted to detect the changes in drought, their frequencies and trends in the Kirindi Oya river basin in Sri Lanka using Standardized Precipitation Index (SPI) and Streamflow Drought Index (SDI). The frequency of drought events was assessed using SPI and trend of SPI was also determined using Mann - Kendall and Sens slope. The results based on SPI analysis indicated that hydrological years 1989-90, 1991-92, 2000-01 and 2013-14 were drought years and the year 1991-92 was identified as a severe drought year in the Kirindi Oya river basin. The significant negative trend of SPI (-0.055) during July to September time scale indicates the increasing drying tendency of the entire basin. However, frequency of being dry of the basin in annual and April to September period is only 16% for the entire basin. Based on SDI, 2000-01 and 2003-04 were identified as hydrological drought years especially for the October to December period both at Thanamalwila and Wellawaya gauge stations in the basin.
    Keywords: drought analysis; Kirindi Oya river basin; SPI index; SDI index; Sri Lanka.

  • Rainfall Trends and Intensity-Frequency-Duration Relationships in Sharjah City, UAE   Order a copy of this article
    by Abdullah Yilmaz, Abdallah Shanableh, Tarek Merabtene, Serter Atabay, Naseraldin Kayemah 
    Abstract: Trend analysis is important to understand effects of climate change and variability on rainfalls. In this study, rainfall and heavy rainfall trend analysis were performed for Sharjah City, United Arab Emirates (UAE) using data for various rainfall durations. Moreover, rainfall intensity-frequency-duration (IFD) relationship was studied by fitting annual maximum and peaks-over-threshold data to Generalized Extreme Value (GEV) and Generalized Pareto Distributions (GPD). Mostly decreasing rainfall trends were detected for short storm durations (except autumn season rainfall), whereas statistically non-significant rainfall trends were detected for long storm durations. Also, statistically non-significant increasing trends were detected in heavy rainfalls in Sharjah City. Heavy rainfall data sets were fit successfully to GEV and GPD, and rainfall IFD relationship was created for Sharjah City. Despite the availability of limited data for study area, this study contributed to better understanding of variations in rainfall and heavy rainfalls in Sharjah City. Moreover, derived rainfall IFD relationships by frequency analysis of generated heavy rainfalls (using multiple techniques to overcome limited data availability challenge) provide significant input for water infrastructure projects in Sharjah City.
    Keywords: Rainfall trends; Rainfall IFD curves; Heavy rainfalls; Sharjah City; United Arab Emirates.