International Journal of Water (10 papers in press)
Investigating the effect of climate change on inflow into Karun-4 dam based on IPCC's fourth and fifth reports
by Afshin Mansouri, Babak Aminnejad, Hassan Ahmadi
Abstract: In the present paper, fluctuations of inflow into Karun-4 dam under different climate change scenarios for the future period of 2021-2050 have been investigated. For this purpose, the outputs of HadCM3 model under the scenarios of B1 (optimistic) and A2 (pessimistic) were used for the IPCC fourth assessment report. Additionally, the outputs of the ensemble model under RCP 2.6 (optimistic) and RCP 8.5 (pessimistic) scenarios were used for the IPCC fifth assessment report. Furthermore, to estimate discharge in the future period, artificial neural network (ANN) was considered as a rainfall-runoff model. Results indicated that the average annual precipitation in the five study stations under B1 and RCP 2.6 scenarios increased by 15% and 5%, respectively, and showed a decrease equal to 8% and 6%, respectively, under A2 and RCP 8.5 scenarios. Moreover, the average annual temperature in all scenarios showed increases, which were at least 1.06 oC under B1 scenario and 1.89 oC under RCP 8.5 scenario. Examining the inflow into the Karun-4 dam showed that under both B1 and RCP 2.6 scenarios, the annual inflow would increase by 1.8% and 1.5%, respectively, and under the two scenarios A2 and RCP 8.5, the annual inflow would decrease by 10.4% and 9.8%, respectively.
Keywords: HadCM3 model; ensemble model; optimistic scenarios; pessimistic scenarios.
Discharge prediction in meandering compound channels
by Arpan Pradhan, Kishanjit Kumar Khatua
Abstract: Reliable prediction of discharge is the foremost requirement for the safety of river work and flood management. The striking feature of a meandering channel makes its distinguishably unique for analysis; hence in this paper a concern on discharge prediction methods is presented. Parameters related to channel geometry and flow characteristics, including effects of secondary current produced along the flow, momentum transfer across the main channel and floodplain, and formation of shear layer due to flow of water from flood plain into main channel, are discussed briefly. In total seven datasets from a large scale channel facility (FCF phase B) at Wallingford (1991), higher sinuous channel data of Willetts and Hardwick at University of Aberdeen (1993) and the data observed at NIT Rourkela by Khatua (2008) and Mohanty (2013) are taken for analysis. The experimental collected discharge data are used to compare the discharge predicted by three well known existing methods, i.e. channel division methods by Greenhill and Sellin (1993), theoretical and empirical methods by James and Wark (1992) and the dimensional analysis method by Shiono and Knight (1999). Relative error is calculated to check the degree of exactness given by each method and is used as a utility tool to decide the effectiveness of the mentioned methods. The adequacy of each method is known by going through its applicability and limitations. Hence the paper provides a comparative study and error analysis of the different discharge methodologies over a wide variety of datasets.
Keywords: meandering channel; discharge prediction; secondary current; momentum transfer; error analysis.
An urban flood inundation model based on cellular automata
by Saman Armal, Rafea Al-Suhili
Abstract: This study develops a modified Cellular Automata (CA) model to simulate the flash flood inundation extent on a case study of an urban sub-catchment, in New York City. Based on the soil composition, the Horton equation is modified with threshold infiltration rates applied to different land cover types. Further, the orifice equation is updated with a time-variant parameter to account for partial/full blockage in the inlets. We propose a slope-weighted flow transfer function to adjust the CA model and address the problem of depth positivity and flow regime changes, occurring due to the partial submergence. Seven ponding points with different levels of inundation are detected in the survey of the area and accordingly compared with the output of the simulation. The results prove the applicability of developed CA model to reproduce the evolution of water depth.
Keywords: urban flooding; flash flood; cellular automata.
Proposing the minimum and maximum probable WQI indices for better water quality management in poor and underdeveloped countries (case study: Bilghan intake)
by Ali Dehnavi, Pardis Goudarzian
Abstract: Increasing the measurements cost for surface water quality assessment besides the need for continuous measurements will be cause a dilemma in poor countries. Therefore, a new method was proposed to identify and predict minimum probable WQI (MIP-WQI) and maximum probable WQI (MAP-WQI) values instead of the traditional ones by combining available WQI data and Taguchi method. For this purpose, the water quality data of Bilghan station on the Karaj River were used for prediction and comparison of the MIP-WQI and the MAP-WQI. According to the surveys and based on the proposed method, the MIP-WQI and the MAP-WQI values based on 2008s data were estimated 61.6 and 87.4, respectively. Whereas, from 2008 to 2010, actual minimum WQI values were 65.9, 69.8 and 69.3, respectively. In addition, actual maximum WQI values were 83.1, 77.2 and 75.6, respectively. Moreover, these probable indices could be more suitable to use for water management, especially in poor and underdeveloped countries.
Keywords: water quality index; surface water quality; water quality management; catchment area; empirical index; Bilghan intake; Taguchi method; minimum probable WQI; maximum probable WQI.
Sustainable urban development through a blue and green network approach focusing the protection of water resources: the case of the Belo Horizonte Metropolitan Region, in Brazil
by Nilo Nascimento, Julian Eleuterio, Heloisa Costa, Brigitte Vinçon-Leite, Ana Mourao, Diomira Faria, Roberto Monte-Mor
Abstract: This paper explores the potentialities offered by blue-green approaches to promote protection of water resources at the metropolitan scale and to contribute to structuring territorial development. An ongoing experience of regional planning and land use regulation in the Belo Horizonte Metropolitan Region (BHMR), in Brazil, is here a reference. With a population of 5.8 million inhabitants and territory of 10,000 km2, the BHMR offers a rich example of land use diversity that highlights the complexity of metropolitan territorial planning and management. In the first part of the paper, blue-green concepts are developed emphasising their role for the protection of water resources. This is followed by the methods and results of applying these concepts to the BHMR. We then evaluate whether blue-green approaches are sufficient to protect water resources and discuss the potentialities of additional tools such as the payment for environmental services with the same objectives.
Keywords: metropolitan areas; water resource protection; metropolitan development planning; blue-green approach; metropolitan zoning; participatory process; participatory planning; drinking water supply; sources of drinking water; green corridors.
Development of prediction model for forecasting rainfall in Western Australia using lagged climate indices
by Farhana Islam, Monzur Imteaz
Abstract: The main aim of the study was to develop a model to forecast autumn rainfall several months in advance for the south-west division (SWD) of Western Australia (WA). For any rainfall forecasting approach, it is necessary to have a wide understanding of the behaviour of potential climate indices with rainfall variability. This study identifies and incorporates the relationship among major climate indices such as Dipole Mode Index (DMI), Southern Oscillation Index (SOI), ENSO Modoki Index (EMI) and autumn rainfall in SWD of WA. Significant correlations among lagged climate indices with autumn rainfall were evaluated. Eight rainfall stations from two separate regions of SWD were considered for this study. From statistical analysis, it was found that DMI, SOI, Nino3.4, Nino3 and Nino4 have shown significant correlations with autumn rainfall for all the stations. On the other hand, EMI showed significant correlations only for the stations on the north coast. DMI effect has been found stronger for all the stations compared with other climate indices. Several multiple regression analyses were conducted using lagged ENSO-DMI, lagged SOI-DMI and lagged EMI-DMI indices. Results showed that multiple regression has significantly increased the correlations between autumn rainfall and climate indices. Finally, developed models were tested without the sample dataset and statistically significant models were suggested.
Keywords: climate indices; dipole mode index; El Nino southern oscillation; southern oscillation index; ENSO Modoki index.
Hydrogeochemical assessment of groundwater quality: a case study from Adamawa in northeastern Nigeria
by Ahmed B. Seli, Buba Apagu Ankidawa, Jackson M. Ishaku, Mohammed D. Aminu
Abstract: This research is aimed at assessing the hydrogeochemistry of groundwater in Ganye (northeastern Nigeria) and environs using multivariate statistical analysis. A total of 30 water samples, 14 from boreholes and 16 from hand-dug wells, were collected from the research area. The abundance of the cation concentrations is in the order of Ca2+>Mg2+>K+ Cl- CO32-. The sodium absorption ratio values range from 0.077 to 1 meq/l with an average of 0.423 meq/l. The residual sodium carbonate values range from -1.392 to 3.332 meq/l with an average of 0.106 meq/l. The soluble sodium percentage ranges from 3.965% to 249.5% with an average of 17.7%. The magnesium ratio ranges from 34.51 to 67.03% with an average of 53.19%. About 70% of the water sources are unsuitable for agricultural use as they have magnesium ratios >50%. Total hardness ranges from 60 to 89 mg/l with an average of 73.18 mg/l. Electrical conductivity ranges from 149 to 431
Keywords: Ganye Nigeria; groundwater; hydrogeochemistry; multivariate statistical analysis; water quality index.
Frictional head loss relation between Hazen-Williams and Darcy-Weisbach equations for various water supply pipe materials
by Rehan Jamil
Abstract: This research presents the analytical relationship between the frictional head loss obtained by two of the most common equations, Darcy-Weisbach and Hazen-Williams, considering plastic and metallic pipe materials as major categories. A wide range of hydraulic situations have been covered for the water supply system for buildings through five models for each pipe material category, based on water temperatures ranging from 20 oC to 60 oC, pipe diameters from 15 mm to 50 mm and volume flow-rates from 0.25l ps to 2l ps. The head loss values obtained by both equations were used to establish the correlation between them by using statistical techniques. The analysis showed reliable results with a combined correlation coefficient of 0.981 between the two equations for plastic and metallic pipes, while the R2 value for the trend line of head loss values obtained by these equations was found to be 0.9978. This relationship will prove to be very useful for the water supply pipe manufacturers and designers for the mutual conversion of frictional head loss values obtained by these equations.
Keywords: Darcy-Weisbach; Hazen-Williams; analytical relation; water supply; pipe materials; fluid dynamics; regression analysis.
The long-term trend analysis of rainfall data from 1901 to 2015 for Maharashtra and Goa regions in India
by Swapnil S. Potdar, Shreyas Kulkarni, Priyanka Patil, Rani P. Pawar, Vineet V. Jakhalekar, Dada P. Nade
Abstract: In this work, the long-term trend analysis is carried out on the time series of annual and southwest (SW) monsoon rainfall over Maharashtra and Goa regions in India. This time series of rainfall has a long period of 115 years from 1901 to 2015. The four meteorological subdivisions covering Maharashtra and Goa regions, (i) Konkan and Goa, (ii) Madhya-Maharashtra, (iii) Marathwada, and (iv) Vidarbha, having a homogeneous climate, are considered to study the spatial variation of long-term trend analysis in the annual and SW monsoon rainfall. The well-known linear regression analysis, Mann-Kendall analysis test and Sens slope estimator methods are used to detect the trend and its significance. Our results show that the long-term trend in annual as well as SW monsoon over Maharashtra as a whole, Konkan and Goa and Madhya Maharashtra are increasing, while over Marathwada and Vidarbha regions they are decreasing. The numbers of normal, drought and flood years are also calculated. We found maximum flood years (22) for Konkan and Goa and maximum drought years (21) for Vidarbha subdivision.
Keywords: rainfall trend; Mann-Kendall test; Sen’s slope; regression analysis.
The effects of climate change on crop yields using RCP scenarios with SWAT agro-hydrological model in Maharloo basin, Fars Province, Iran
by Fatemeh Moazami Goudarzi, Amirpouya Sarraf, Hassan Ahmadi
Abstract: Climate change is one of the most important issues that have been raised in water sources and agriculture limiting the crop production. In this study, the northern part of the Maharloo Lake in the central plateau of Iran is simulated using a semi-distributed SWAT model during 1980-2013. Then, using the LARS-WG, future climate information is obtained based on RCP 4.5 and RCP8.5 scenarios. Furthermore, assessment of the effects of climate change showed that the average annual temperature of the basin in the future period (2021-2040) will increase about 1.5
Keywords: Maharloo Lake; LARS-WG downscaling model; semi-distributed SWAT model; Maharloo Basin.