Showing papers in "International Journal of Hydrology Science and Technology in 2020"

Corrosion and deposition in Karoon River, Iran, based on hydrometric stations

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 Ryznar and Langelier indicators have been used and after the necessary calculations it has been determined that the river water has a negative Langelier index (LSI 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).

Evaluation of uncertainty in evapotranspiration values by FAO56-Penman-Monteith and Hargreaves-Samani methods

Abstract: Methods of calculating evapotranspiration are subject to uncertainty. 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 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 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.

Climate change impact on groundwater recharge of Umm er Radhuma unconfined aquifer Western Desert, Iraq

Abstract: The impact of future climate change on groundwater resources is significant, especially for arid and semi-arid areas such as the Middle East. 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 modelling 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 seven selected meteorology stations throughout the study area. The results indicated an increase in annual precipitation and in average temperature for the two selected scenarios. For the study region, precipitation is predicted to increase by 5.4% and 3.19%, for A2 and B2 scenarios, respectively. Consequently, the annual average groundwater recharge is expected to decrease by 16% for both scenarios in the next century.

Quantifying Tigris Riverbanks stability of Southeast Baghdad City using BSTEM

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 ...

Evaluation of multiple satellite-derived rainfall products over Morocco

Abstract: The focus of this study is to assess the accuracy of four satellite-based rainfall estimations in Morocco. TRMM3B42V7, ARC2, RFE2.0 and PERSIANN-CDR are evaluated with observations from 19 meteorological stations, at daily and monthly time steps, over different seasons and different classes of topography for the period 2001-2014. Results show that, all satellite datasets reasonably reproduce the mean annual rainfall and the seasonal cycle. In terms of rainfall day statistics, ARC2 and RFE2.0 have performed the best while PERSIANN-CDR exhibited the worst performance. Categorical indices showed that the TRMM3B42V7 product outperforms others in both the boreal summer and the rain shadow area. For the total precipitation, all satellite products underestimate rainfall amount in low and mid elevation, whereas a marked overestimation is observed over the rain shadow area. In terms of rainfall intensity, TRMM3B42V7 exhibits good performance to reproduce high rainfall intensities.

Interbasin water transfer conflicts. The case of the Tagus-Segura Aqueduct (Spain)

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.

Assessment of meteorological and hydrological drought; a case study in Kirindi Oya river basin in Sri Lanka

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 standardised 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 Sen's slope. The results based on SPI analysis indicated that hydrological years 1989-1990, 1991-1992, 2000-2001 and 2013-2014 were drought years and the year 1991-1992 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, 2000-2001 and 2003-2004 were identified as hydrological drought years especially for the October to December period both at Thanamalwila and Wellawaya gauge stations in the basin.

Modelling runoff in a river basin, India: an integration for developing un-gauged catchment

Abstract: Stage-runoff model based on nonlinear 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.

Rainfall trends and intensity-frequency-duration relationships in Sharjah City, UAE

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, UAE. Moreover, rainfall intensity-frequency duration (IFD) relationship was studied by fitting heavy rainfall data to extreme value distributions. Mostly decreasing rainfall trends were detected for short storm durations, 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 extreme value distributions, 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 provide significant input for water infrastructure projects in Sharjah City.

Revisiting maximum observed precipitation and discharge envelope curves

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.

Leaching of organic material in polymeric pipes distributing desalinated water

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 (OM). 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 (DBP) was present in PVC pipes, compared to PPR and PE pipes.

The influence of particle shape and gradation parameters on the permeability of filter media

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.

Assessment of factors affecting bromate formation in drinking water bottles

Abstract: This paper presents the results of experimental study conducted to investigate the effects of different parameters on bromate formation in bottles of drinking water. The effects of various temperatures, storage times, pH and some water quality parameters including bromide, total organic carbon (TOC) and total dissolved solids (TDS) were investigated. Three different regional and international water bottles brands available in the United Arab Emirates (UAE) were selected. For each brand 36 polyethylene terephthalate (PET) bottles of water were used for the experimental study. It is concluded that the effects of storage time and temperature was negligible for all brands and that the effects of pH levels on bromate formation was noticeable. Increasing pH level increases the bromate formation for brands X and Y but decreases the bromate formation for brand Z. It is also concluded the effect of TDS, TOC and turbidity on bromate formation was not significant.

Statistical and trend analyses of long-term rainfall data: a case study for Mauritius

Abstract: This paper focuses on the analysis of monthly 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.

Rainwater harvesting in urban areas of developed countries. The state of the art (1980-2017)

Abstract: Many urban areas suffer from water scarcity although paradoxically, a local source such as rainwater is mostly treated as a risk rather than a valuable resource. This change of paradigm is included in the 'integrated water resources management' and 'demand management' approach. The aim of this research is to identify and analyse studies that explore subject matters concerning rainwater in the integrated management systems of water resources into developed countries. The research methodology consisted in a literature review (from the 1980s to 2017) of territorial studies that examine rainwater harvesting in urban areas of the developed countries. To this end, a bibliometric analysis has been carried out in different databases according to the definition of keywords. The results reveal five thematic areas were identified and temporal and spatial differences between some subject matters.

Design criteria of protective filters based on particle shape and gradation parameters

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.

Damaging hydrological events during the exiting of the Little Ice Age in a highland area of Southern Italy

Abstract: Historical documentary sources reflect a myriad of social, cultural, political, and scientific narratives about weather, climate and hydrological effectiveness. Their use in climate research provides an important contribution to current debates about climate and related damaging hydrological events. In Europe, the end of the Little Ice Age (LIA, 1840-1920) was characterized by an unusual mixture of storms, floods and landslides. They have marked profoundly the regional landscape of the highlands of the Tammaro area (Campano Apennines, Southern Italy). In this way, we found that episodes of climate variability and its extremes have often disrupted ecosystems during stormy wintertimes (September-March) by injuring plant development phases, and causing sometimes disruption, while also creating new interactions with the agricultural and social environment. The results indicated that the end of the 19th century was the stormiest period of the series 1800-2000, in conjunction with landscape deforestation started in 1850.

Potentiality of irrigation technologies to control soil salinity and greenhouses pepper yield production improvement in sandy soil of Southern Tunisia

Abstract: Localised surface drip irrigation (DI) is used to irrigate pepper crop in a greenhouse with two irrigation treatments 100% (T1) and 50% (T2) of the plant needs. The DI system is compared with a new irrigation technique called buried diffuser (BD). Irrigation treatment, soil depth, soil electrical conductivity (EC) and pepper yield production were used to compare between the irrigation systems using generalised additive mixed model (GAMM). The results indicated that yield production increased from 23,047 kg/ha under DI to 23,945 kg/ha under BD using T1 treatment. By using T2 treatment, the yield production was 13,164 kg/ha under DI and 15,703 kg/ha under BD. Moreover, BD helped to eliminate the salinity in the root zone for the T1 treatment. While it has the same effect on soil salinity as the T2 treatment of the DI. Under T1 and T2, the yield obtained from BD was significantly higher that DI.

Probabilistic estimation of design runoff curve number: a case study for Shakkar river watershed, India

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 one, two and three-day was fitted with three probability distribution [log-normal (LN), Gumbel 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. Probabilistic estimation of one, two and three-day maximum runoff is important for safe and cost effective planning and design of surface runoff storage system.

Derivation of digital terrain models and morphological parameters from very high resolution satellite images

Abstract: Jordan is considered among the poorest countries in water resources in the world; therefore, many projects were introduced to the area to deal with this issue. The presented work focuses on two specific aspects - that could help in water resources management projects - the accuracy potential of these data in such areas and the benefit for hydrological models and applications using these data. We present methodology, ground truth validation and assessment for digital terrain model (DTM) generation by Pleiades data as well as for the derivation of drainage networks and morphometric parameters. The results were compared with DTM generated from laser scanning from airborne platforms (LiDar) data, which showed the ability of Pleiades data to generate DTMs in mountainous regions, and steep areas. The drainage density and morphometric parameters were also tested and compared. The absolute mean difference in elevation for the generated DTM from Pleiades data was 0.444 m (less than 1 pixel) with 0.509 standard deviation and root mean square error (RMSE) of 0.503, where the computed drainage density from both LiDar Pleiades data showed no significant difference.