Applied Water Science (v.7, #3)

Drinking water contamination and treatment techniques by S. Sharma; A. Bhattacharya (1043-1067).
Water is of fundamental importance for life on earth. The synthesis and structure of cell constituents and transport of nutrients into the cells as well as body metabolism depend on water. The contaminations present in water disturb the spontaneity of the mechanism and result in long/short-term diseases. The probable contaminations and their possible routes are discussed in the present review. Continued research efforts result in some processes/technologies to remove the contaminations from water. The review includes concepts and potentialities of the technologies in a comprehensible form. It also includes some meaningful hybrid technologies and promising awaited technologies in coming years.
Keywords: Water; Contaminants; Purification; Hybrid technology

Decentralized domestic wastewater systems in developing countries: the case study of Harare (Zimbabwe) by Innocent Chirisa; Elmond Bandauko; Abraham Matamanda; Gladys Mandisvika (1069-1078).
Until recently there has been little, if any, concern over revamping let alone improving wastewater management system in Zimbabwe’s urban areas given the dominance and institutionalised water-borne system. Yet, the current constraints in this system and the immensity of urbanisation in the country begs and compels planners, engineers and systems thinkers to rethink what best can work as a sustainable wastewater system. With particular reference to the ever-expanding Harare metropolitan region, this article provides an evaluative analysis on the potentiality, risks and strategies that can be adopted by Harare and its satellites in addressing the problems of the conventional wastewater management system. The suggested framework of operation is a decentralised domestic wastewater collection and treatment system which however has its own multifarious risks. Using systems dynamics conceptualisation of the potentiality, opportunities, risks and strategies, the paper seeks to model the path and outcomes of this decentralised domestic wastewater collection and treatment system and also suggests a number of policy measures and strategies that the city of Harare and its satellites can adopt.
Keywords: Waterborne; Sewerage; Risk; Potential; Strategy; Decentralisation; Food production; Source separation

Plant–microbe interaction in aquatic system and their role in the management of water quality: a review by Jatin K. Srivastava; Harish Chandra; Swinder J. S. Kalra; Pratibha Mishra; Hena Khan; Poonam Yadav (1079-1090).
Microbial assemblage as biofilm around the aquatic plant forms a firm association that largely depends upon the mutual supplies of nutrients, e.g., microbes interact with plants in an aquatic system most likely for organic carbon and oxygen, whereas plants receive defensive immunity and mineral exchange. Apart from the mutual benefits, plant–microbe interactions also influence the water quality especially at rhizosphere providing inherent ability to the aquatic system for the mitigation of pollution from the water column. The review presents and in-depth information along with certain research advancements made in the field of ecological and bio/chemical aspects of plant–microbe interactions and the underlying potential to improve water quality.
Keywords: Plant–microbe interaction; Aquatic plants; Biofilm; Rhizosphere; Pollution mitigation; Bio/chemical interaction

Hydrofracturing of low-yielding boreholes in hard rocks is a widely used technique in Africa for improvement of yield, thus making them qualified for installation of a hand-pump for domestic water supply. However, the success rate of the hydrofracturing campaigns seems not to be that high as generally claimed by contractors. One reason amongst others might be that the selection of zones for hydrofracturing in the individual borehole is based on pre-hydrofracturing investigation using conventional electrical logs only. Thereby, the zones selected are the occurring resistivity minima interpreted as weak zones with some fracturing. However, resistivity minima can also be caused solely by lithological reasons, which then in most cases could have been seen on a gamma log as corresponding increased gamma radiation. The advantages of using gamma logging in combination with conventional electrical logging technique for prediction of fractured zones in basement rocks is illustrated by investigations of three low-yielding boreholes located in different geological environments in crystalline basement rocks in Ghana.
Keywords: Groundwater; Gamma radiation; Borehole logging; Fracture zone; Hard rock; Ghana

The Hammamet Plain, situated in the northwest of the Tezbent mountain range, northeast of Algeria, drains carbonate aquifers through some important karst springs. The physical and chemical characteristics of spring and well water samples were studied for 2 years to assess the origin of groundwater and determine the factors driving the geochemical composition. The ionic speciation and mineral dissolution/precipitation was calculated. Water wells, characterizing groundwater circulation at shallow depths, are moderate to high mineralized waters of Na–HCO3 type. In contrast to the shallow environment, the CO2-rich, deeper waters are of the Ca–HCO3–SO4 type and undergo significant changes in the baseline chemistry along flow lines with increasing residence time. The main factors controlling the groundwater composition and its seasonal variations are the geology, because of the presence of carbonate formations, the elevation and the rate of karst development. In both groups, the carbonate chemistry is diagnostic of the effect of karst development. The supersaturation with respect to calcite indicates CO2 degassing, occurring either inside the aquifer in open conduits, or at the outlet in reservoirs. The undersaturation with respect to calcite shows the existence of fast flow and short residence time conditions inside the aquifer. Interaction between groundwater and surrounding host rocks is believed to be the main process responsible for the observed chemical characteristics of groundwater in the study area.
Keywords: Karst aquifer; Hydrochemistry; Saturation indices; Tezbent; Algeria

Water quality monitoring of an international wetland at Harike, Punjab and its impact on biological systems by Jasmit Kaur; Harpreet Walia; Samson Okongo Mabwoga; Saroj Arora (1107-1115).
The present study entails the investigation of mutagenic and genotoxic effect of surface water samples collected from 13 different sites of the Harike wetland using the histidine reversion point mutation assay in Salmonella typhimurium (TA98) strain and plasmid nicking assay using pBR322, respectively. The physicochemical characterization of water samples using different parameters was conducted for water quality monitoring. Heavy metal analysis was performed to quantify the toxic components present in water samples. It was observed that although the water samples of all the sites demonstrated mutagenic as well as genotoxic activity, the effect was quite significant with the water samples from sites containing water from river Satluj, i.e., site 1 (upstream Satluj river), site 2 (Satluj river) and site 3 (reservoir Satluj). The high level of pollution due to industrial effluents and agricultural run-off at these sites may engender the genotoxicity and mutagenicity of water samples.
Keywords: Harike; Ramsar; Ames; Plasmid nicking; Monitoring

Hydrogeochemical and isotopic studies of groundwater in the middle voltaian aquifers of the Gushegu district of the Northern region by Musah Salifu; Sandow Mark Yidana; Maxwell Anim-Gyampo; Michael Appenteng; David Saka; Felix Aidoo; Enoch Gampson; Mark Sarfo (1117-1129).
This work is to establish the hydrochemistry and origin of groundwater in some parts of the Gushegu district of the Northern Region of Ghana. Hydrochemical data from 19 groundwater and 7 rock samples have been used to evaluate water quality, water types, and sources of various ions as well as origin of the groundwater. The study results show that the quality of groundwater from the area is generally not good due to their fluoride (F), bicarbonate (HCO3 ) and electrical conductivity (EC) concentrations. The F contents of the groundwater have values as high as 1.97 mg/L, with 53 % of the groundwater having concentrations of F exceeding the WHO recommended allowable limits. These high F values have the potential of causing serious health problems such as kidney failure, dental and skeletal fluorosis, reproductive problem and reduction in intelligent quotient of consumers. A plot of Gibbs diagram reveals that rock weathering and precipitation are the major hydrogeochemical processes regulating the water chemistry of the study area. Petrographic thin-section analyses of rock samples identify minerals present to be muscovite, plagioclase feldspars, quartz, sericite and iron oxide. Stable isotope (18O and 2H) composition of the waters reveals that most of the groundwater is likely to be recharged from local precipitation, indicating their meteoric origin. Some samples, however, showed considerable evaporation.
Keywords: Gushegu; Fluoride; Voltaian aquifers; Muscovite; Sericite; Stable isotopes

Multivariate statistical technique and hydrogeochemical approach were employed for groundwater assessment within the Lower Pra Basin. The main objective was to delineate the main processes that are responsible for the water chemistry and pollution of groundwater within the basin. Fifty-four (54) (No) boreholes were sampled in January 2012 for quality assessment. PCA using Varimax with Kaiser Normalization method of extraction for both rotated space and component matrix have been applied to the data. Results show that Spearman’s correlation matrix of major ions revealed expected process-based relationships derived mainly from the geochemical processes, such as ion-exchange and silicate/aluminosilicate weathering within the aquifer. Three main principal components influence the water chemistry and pollution of groundwater within the basin. The three principal components have accounted for approximately 79% of the total variance in the hydrochemical data. Component 1 delineates the main natural processes (water–soil–rock interactions) through which groundwater within the basin acquires its chemical characteristics, Component 2 delineates the incongruent dissolution of silicate/aluminosilicates, while Component 3 delineates the prevalence of pollution principally from agricultural input as well as trace metal mobilization in groundwater within the basin. The loadings and score plots of the first two PCs show grouping pattern which indicates the strength of the mutual relation among the hydrochemical variables. In terms of proper management and development of groundwater within the basin, communities, where intense agriculture is taking place, should be monitored and protected from agricultural activities. especially where inorganic fertilizers are used by creating buffer zones. Monitoring of the water quality especially the water pH is recommended to ensure the acid neutralizing potential of groundwater within the basin thereby, curtailing further trace metal mobilization processes in groundwater within the basin.
Keywords: Groundwater pollution; Hydrogeochemical processes; Principal component analysis (PCA); Lower Pra Basin; Ghana

GMDH algorithms applied to turbidity forecasting by Tsung-Min Tsai; Pei-Hwa Yen (1151-1160).
By applying the group method of data handling algorithm to self-organization networks, we design a turbidity prediction model based on simple input/output observations of daily hydrological data (rainfall, discharge, and turbidity). The data are from a field test site at the Chiahsien Weir and its upper stream in Taiwan, and were recorded from May 2000 to December 2008. The model has a regressive mode that can assess the estimated error, i.e., whether a threshold has been exceeded, and can be adjusted by updating the field input data. Consequently, the model can achieve accurate estimations over long-term periods. Test results demonstrate that the 2006 turbidity prediction model was selected as the best predictive model (RMSE = 5.787 and CC = 0.975) because of its ability to predict turbidity within the acceptable error range and 90 % required confidence interval (50NTU). 70(3,1,1) is the optimum modeling data length and variable combinations.
Keywords: GMDH; Turbidity forecast; Nanhua Reservoir; Chiahsien Weir; Over-basin diversion

Groundwater, which is renewable under current climatic conditions separately from other natural sources, in fact is a finite resource in terms of quality and fossil groundwater. Researchers have long emphasized the necessity of exploiting, operating, conserving and managing groundwater in an efficient and sustainable manner with an integrated water management approach. The management of groundwater needs reliable information about changes on groundwater quantity and quality. Environmental isotopes are the most important tools to provide this support. No matter which method we use to calculate the groundwater budget and flow equations, we need to determine boundary conditions or the physical boundaries of the domain. The Groundwater divide line or basin boundaries that separate the two adjacent basin recharge areas from each other must be drawn correctly to be successful in defining complex groundwater basin boundary conditions. Environmental isotope data, as well as other methods provide support for determining recharge areas of the aquifers, especially for karst aquifers, residence time and interconnections between aquifer systems. This study demonstrates the use of environmental isotope data to interpret and correct groundwater basin boundaries giving as an example the Yeniçıkrı basin within the main Sakarya basin.
Keywords: Groundwater basin; Groundwater divide line; Recharge area; Isotope

An improved produced water reinjection (PWRI) model that incorporates filtration, geochemical reaction, molecular transport, and mass adsorption kinetics was developed to predict cake deposition and injectivity performance in hydrocarbon aquifers in Nigeria oil fields. Thus, the improved PWRI model considered contributions of geochemical reaction, adsorption kinetics, and hydrodynamic molecular dispersion mechanism to alter the injectivity and deposition of suspended solids on aquifer wall resulting in cake formation in pores during PWRI and transport of active constituents in hydrocarbon reservoirs. The injectivity decline and cake deposition for specific case studies of hydrocarbon aquifers in Nigeria oil fields were characterized with respect to its well geometry, lithology, and calibrations data and simulated in COMSOL multiphysics software environment. The PWRI model was validated by comparisons to assessments of previous field studies based on data and results supplied by operator and regulator. The results of simulation showed that PWRI performance was altered because of temporal variations and declinations of permeability, injectivity, and cake precipitation, which were observed to be dependent on active adsorption and geochemical reaction kinetics coupled with filtration scheme and molecular dispersion. From the observed results and findings, transition time t r to cake nucleation and growth were dependent on aquifer constituents, well capacity, filtration coefficients, particle-to-grain size ratio, water quality, and more importantly, particle-to-grain adsorption kinetics. Thus, the results showed that injectivity decline and permeability damage were direct contributions of geochemical reaction, hydrodynamic molecular diffusion, and adsorption kinetics to the internal filtration mechanism, which are largely dependent on the initial conditions of concentration of active constituents of produced water and aquifer capacity.
Keywords: Reinjection; PWRI; Cake formation; Aquifer; Adsorption kinetics; Produced water

In Nigeria, more than 60 million people are required to meet Millennium Development Goals (MDGs) target for improved water by 2015 and is unlikely to be achieved only by public supply. To cover these water availability gaps water vendors exist and ignoring their role is potentially deceptive. The aim of this paper is to assess the role of water vendors in meeting these peoples’ need and elicit household’s willingness-to-pay for improved supply. The research includes cross-sectional mixed method in which questionnaire survey was performed to 218 households; and interviews and focus group discussion were conducted with water vendors. Findings reveal that water vendors supplied most households irrespective of season. Retail vendors buy 25 l at ₦4.00 ($0.013) from wholesale vendors and resale at ₦20.08 ($0.07) during dry and at ₦14.02 ($0.05) in wet season. The price is 28 and 40 times the cost of in-house connection from Kano State Water Board (KNSWB) during rainy and dry season, respectively. Vendors who buy from hand-dug wells pay ₦100.00 ($0.33) per day and draw as much water within that day. Furthermore, willingness-to-pay for in-house connection was elicited as ₦367.00 ($1.20), lower than monthly flat fixed tariff set by KNSWB. The study recommends recognizing vendors formally in form of public private partnership so that technical and financial support be given, thus their activities and charges be regulated. People’s perception on water should be changed through education and enlightening. Further research should focus on estimating total volume of water supplied by water vendors.
Keywords: Water vendors; Nigeria; Low income; Water supply; Households; Willingness-to-pay

Hydrochemical characterization of groundwater in around Tirupati Area, Chittoor District, Andhra Pradesh, South India by E. Balaji; A. Nagaraju; Y. Sreedhar; A. Thejaswi; Zahed Sharifi (1203-1212).
In the management of water resources, quality of water is just as important as its quantity. The main aim of this study has been to assess the variability of groundwater parameters to develop water quality of Tirupati area and its suitability for domestic and irrigation purpose. Further, the samples were analyzed for pH, EC, TDS, carbonates, bicarbonates, alkalinity, chlorides, sulfates, hardness, fluoride, calcium, magnesium, sodium, and potassium. Based on the analytical results, chemical indices like percent sodium, sodium absorption ratio (SAR), adjusted SAR, percent sodium (Na %), residual sodium carbonate (RSC) and permeability index (PI) have been calculated. Chadha rectangular diagram for geochemical classification and hydrochemical processes of groundwater indicated that most of waters are Ca–Mg–HCO3 and Ca–Mg–Cl types. Assessment of water samples from various methods indicated that majority of the water samples are suitable for domestic and irrigation purpose.
Keywords: Groundwater quality; Irrigation; Base-exchange indices; Gibbs ratio; Tirupati; South India

Computational  Modeling of Pollution Transmission in Rivers by Abbas Parsaie; Amir Hamzeh Haghiabi (1213-1222).
Modeling of river pollution contributes to better management of water quality and this will lead to the improvement of human health. The advection dispersion equation (ADE) is the government equation on pollutant transmission in the river. Modeling the pollution transmission includes numerical solution of the ADE and estimating the longitudinal dispersion coefficient (LDC). In this paper, a novel approach is proposed for numerical modeling of the pollution transmission in rivers. It is related to use both finite volume method as numerical method and artificial neural network (ANN) as soft computing technique together in simulation. In this approach, the result of the ANN for predicting the LDC was considered as input parameter for the numerical solution of the ADE. To validate the model performance in real engineering problems, the pollutant transmission in Severn River has been simulated. Comparison of the final model results with measured data of the Severn River showed that the model has good performance. Predicting the LDC by ANN model significantly improved the accuracy of computer simulation of the pollution transmission in river.
Keywords: Pollution transmission; Advection dispersion equation (ADE); Multilayer perceptron neural network (MLP); Finite volume method (FVM)

Ceria modified activated carbon: an efficient arsenic removal adsorbent for drinking water purification by Radha Sawana; Yogesh Somasundar; Venkatesh Shankar Iyer; Babita Baruwati (1223-1230).
Ceria (CeO2) coated powdered activated carbon was synthesized by a single step chemical process and demonstrated to be a highly efficient adsorbent for the removal of both As(III) and As(V) from water without any pre-oxidation process. The formation of CeO2 on the surface of powdered activated carbon was confirmed by X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The percentage of Ce in the adsorbent was confirmed to be 3.5 % by ICP-OES. The maximum removal capacity for As(III) and As(V) was found to be 10.3 and 12.2 mg/g, respectively. These values are comparable to most of the commercially available adsorbents. 80 % of the removal process was completed within 15 min of contact time in a batch process. More than 95 % removal of both As(III) and As(V) was achieved within an hour. The efficiency of removal was not affected by change in pH (5–9), salinity, hardness, organic (1–4 ppm of humic acid) and inorganic anions (sulphate, nitrate, chloride, bicarbonate and fluoride) excluding phosphate. Presence of 100 ppm phosphate reduced the removal significantly from 90 to 18 %. The equilibrium adsorption pattern of both As(III) and As(V) fitted well with the Freundlich model with R 2 values 0.99 and 0.97, respectively. The material shows reusability greater than three times in a batch process (arsenic concentration reduced below 10 ppb from 330 ppb) and a life of at least 100 L in a column study with 80 g material when tested under natural hard water (TDS 1000 ppm, pH 7.8, hardness 600 ppm as CaCO3) spiked with 330 ppb of arsenic.
Keywords: Removal; Arsenic; Ceria; Activated carbon; Water purification

A combined process of micro-electrolysis, two-phase anaerobic, aerobic and electrolysis was investigated for the treatment of oxidized modified starch wastewater (OMSW). Optimum ranges for important operating variables were experimentally determined and the treated water was tested for reuse in the production process of corn starch. The optimum hydraulic retention time (HRT) of micro-electrolysis, methanation reactor, aerobic process and electrolysis process were 5, 24, 12 and 3 h, respectively. The addition of iron-carbon fillers to the acidification reactor was 200 mg/L while the best current density of electrolysis was 300 A/m2. The biodegradability was improved from 0.12 to 0.34 by micro-electrolysis. The whole treatment was found to be effective with removal of 96 % of the chemical oxygen demand (COD), 0.71 L/day of methane energy recovery. In addition, active chlorine production (15,720 mg/L) was obtained by electrolysis. The advantage of this hybrid process is that, through appropriate control of reaction conditions, effect from high concentration of salt on the treatment was avoided. Moreover, the process also produced the material needed in the production of oxidized starch while remaining emission-free and solved the problem of high process cost.
Keywords: High salt; Oxidized starch wastewater; Combined process; Reuse; Emission-free

The present investigation observed the effect of current density (j), electrocoagulation (EC) time, inter electrode distance, electrode area, initial pH and settling time on the removal of nitrate (NO3 ) and sulphate (SO4 2−) from biologically treated municipal wastewater (BTMW), and optimization of the operating conditions of the EC process. A glass chamber of two-liter volume was used for the experiments with DC power supply using two electrode plates of aluminum (Al–Al). The maximum removal of NO3 (63.21 %) and SO4 2− (79.98 %) of BTMW was found with the optimum operating conditions: current density: 2.65 A/m2, EC time: 40 min, inter electrode distance: 0.5 cm, electrode area: 160 cm2, initial pH: 7.5 and settling time: 60 min. The EC brought down the concentration of NO3 within desirable limit of the Bureau of Indian Standard (BIS)/WHO for drinking water. Under optimal operating conditions, the operating cost was found to be 1.01$/m3 of water in terms of the electrode consumption (23.71 × 10−5 kg Al/m3) and energy consumption (101.76 kWh/m3).
Keywords: Biologically treated municipal wastewater; Electrocoagulation; Nitrate; Operating cost; Sulphate

Plants have gained importance in situ bioremediation of heavy metals. In the present study, different concentrations of zinc (Zn2+) (0.5, 5, 10, 15, 20 mg/l) and lead (Pb2+) (1, 2, 4, 6, 8 mg/l) were used to evaluate metal tolerance level of Lemna minor. L.minor were exposed to metals for 4 days and tested for its dry to fresh weight ratio (DW/FW), photosynthetic pigments production and protein content. The oxidative damage was detected by measuring catalase activity. L.minor showed tolerance against Zn2+ and Pb2+ at a concentration of 10 and 4 mg/l, respectively. Among the metals, Pb2+ showed a significant toxicity at 8 mg/l. High concentration (20 mg/l of Zn2+ and 8 mg/l of Pb2+) of the metals displayed a considerable negative effect on soluble proteins (13 fold decrease with Zn2+ and 4 fold decrease with Pb2+) and photosynthetic pigments (twofold decrease with Zn2+ and onefold decrease with Pb2+) and lead to a consequent reduction in number of fronds. Further, the catalase was greatly increased (twofold decrease with Zn2+ and sixfold decrease with Pb2+) under metal stress. The results indicate that L.minor withstands Zn2+ and Pb2+ toxicity up to the concentration of 10 and 4 mg/l, respectively. Hence, the metal tolerant property of this plant shall be exploited for bioremediation of Zinc and Lead in polluted water. Further, the detailed and wide range of heavy metal toxicity studies should be done to reveal the possible use of this plant on large scale bioremediation purpose.
Keywords: Lemna minor ; Zinc; Lead; Tolerance; Phytoremediation

The sustainable management of groundwater resources is a pressing necessity for most countries. As most of the Arab world is facing severe water scarcity, threats of depletion of non-renewable groundwater, and problems of pollution and salt-water intrusions into groundwater aquifers, much effort should be devoted to eliminate these dangers in advance. This work was devoted to bring up insights into Arab world research activities in groundwater, which is a crucial task to identify their status and can help in shaping up and improving future research activities. A bibliometric analysis has been conducted to track these activities. The study identified 1417 documents which represent 3.3% of global research productivity. Egypt was the most productive country (313; 22.1%), followed by Saudi Arabia (254; 17.9%). Total citations were 9720 with an average of 6.9. The h-index of the retrieved documents was 39, and the highest one was 22 for Egypt. The most common subject category was Environmental Science, and the most productive journal was Arabian Journal of Geosciences (99; 7.0%). In international research collaboration, France was the most collaborated country with Arab world (125; 8.8%), followed by the United States (113; 8.0%). The most productive institution was King Abdul-Aziz University, Saudi Arabia (66; 4.7%). The outcomes shows remarkable improvements in groundwater research activities originated from the Arab world. Even though, constructive efforts should be pursued vigorously to bridge the gaps in groundwater-based research. Moreover, promotion of better evaluation tools to assess the risks arising from the mismanagement of groundwater resources is required urgently.
Keywords: Groundwater; Bibliometric; Scopus; Citation; Impact factor; Arab world

The spinel ZnFe2O4 prepared by nitrate route is used as dispersed photons collector capable to sensitize TiO2 under visible light and to reduce Cr(VI) into trivalent state. The transport properties, optical and photo-electrochemical characterizations are correlated, to build the energetic diagram of the hetero-system ZnFe2O4/TiO2/CrO4 solution. A gap of 1.97 eV is obtained for the spinel from the diffuse reflectance. The conduction band of ZnFe2O4 (−1.47 V SCE) favors the electrons injection into TiO2, permitting a physical separation of the charge carriers. The oxidation of oxalic acid by photoholes prevents the corrosion of the spinel. The best configuration ZnFe2O4 (75 %)/TiO2 (25 %) is used to catalyze the downhill reaction (2HCrO4  + 3C2H4O4 + 1.5O2 + 8H+ → 2Cr3+ + 6CO2 + 11 H2O, ∆G° = −557 kcal mol−1). 60 % of Cr(VI) are reduced after 3 h of visible light illumination and the photoactivity follows a first-order kinetic with a half-life of 70 min. The water reduction competes with the HCrO4 reduction which is the reason in the regression of the photoactivity; a hydrogen evolution rate of 24 µmol mg−1 h−1 is obtained.
Keywords: Spinel; ZnFe2O4 ; Hetero-system; Cr(VI) photoreduction; Visible light

Design flow duration curves for environmental flows estimation in Damodar River Basin, India by Ravindra Kumar Verma; Shankar Murthy; Sangeeta Verma; Surendra Kumar Mishra (1283-1293).
In this study, environmental flows (EFs) are estimated for six watersheds of Damodar River Basin (DRB) using flow duration curve (FDC) derived using two approaches: (a) period of record and (b) stochastic approaches for daily, 7-, 30-, 60-day moving averages, and 7-daily mean annual flows observed at Tenughat dam, Konar dam, Maithon dam, Panchet dam, Damodar bridge, Burnpur during 1981–2010 and at Phusro during 1988–2010. For stochastic FDCs, 7-day FDCs for 10, 20-, 50- and 100-year return periods were derived for extraction of discharge values at every 5% probability of exceedance. FDCs derived using the first approach show high probability of exceedance (5–75%) for the same discharge values. Furthermore, discharge values of 60-day mean are higher than those derived using daily, 7-, and 30-day mean values. The discharge values of 95% probability of exceedance (Q95) derived from 7Q10 (ranges from 2.04 to 5.56 cumec) and 7Q100 (ranges from 3.4 to 31.48 cumec) FDCs using the second approach are found more appropriate as EFs during drought/low flow and normal precipitation years.
Keywords: Flow duration curve; Environmental flows; Damodar river basin

Preparation and characterization of a novel adsorbent from Moringa oleifera leaf by Olugbenga Solomon Bello; Kayode Adesina Adegoke; Opeyemi Omowumi Akinyunni (1295-1305).
A new and novel adsorbent was obtained by impregnation of Moringa oleifera leaf in H2SO4 and NaOH, respectively. Prepared adsorbents were characterized using elemental analysis, FT-IR, SEM, TGA and EDX analyses, respectively. The effects of operational parameters, such as pH, moisture content, ash content, porosity and iodine number on these adsorbents were investigated and compared with those of commercial activated carbon (CAC). EDX results of acid activated M. oleifera leaf have the highest percentage of carbon by weight (69.40 %) and (76.11 %) by atom, respectively. Proximate analysis showed that the fixed carbon content of acid activated M. oleifera leaf (69.14 ± 0.01) was the highest of all adsorbents studied. Conclusively, the present investigation shows that acid activated M. oleifera leaf is a good alternative adsorbent that could be used in lieu of CAC for recovery of dyes and heavy metal from aqueous solutions and other separation techniques.
Keywords: Activation; Adsorbent; Characterization; Impregnation; Moringa oleifera ; Pollutants

Modeling of the adsorptive removal of arsenic(III) using plant biomass: a bioremedial approach by Palas Roy; Uttiya Dey; Soumya Chattoraj; Debasis Mukhopadhyay; Naba Kumar Mondal (1307-1321).
In the present work, the possibility of using a non-conventional finely ground (250 μm) Azadirachta indica (neem) bark powder [AiBP] has been tested as a low-cost biosorbent for the removal of arsenic(III) from water. The removal of As(III) was studied by performing a series of biosorption experiments (batch and column). The biosorption behavior of As(III) for batch and column operations were examined in the concentration ranges of 50–500 µg L−1 and 500.0–2000.0 µg L−1, respectively. Under optimized batch conditions, the AiBP could remove up to 89.96 % of As(III) in water system. The artificial neural network (ANN) model was developed from batch experimental data sets which provided reasonable predictive performance (R 2 = 0.961; 0.954) of As(III) biosorption. In batch operation, the initial As(III) concentration had the most significant impact on the biosorption process. For column operation, central composite design (CCD) was applied to investigate the influence on the breakthrough time for optimization of As(III) biosorption process and evaluation of interacting effects of different operating variables. The optimized result of CCD revealed that the AiBP was an effective and economically feasible biosorbent with maximum breakthrough time of 653.9 min, when the independent variables were retained at 2.0 g AiBP dose, 2000.0 µg L−1 initial As(III) concentrations, and 3.0 mL min−1 flow rate, at maximum desirability value of 0.969.
Keywords: Arsenic(III) removal; Low-cost adsorbent; Biosorption experiments; Artificial neural network model; Central composite design

The matrix material for nanofiltration membranes was prepared through chemical grafting of poly(styrene-co-chloromethylstyrene) (PSCMS) to DGEBA using hexamethylenediamine as linker. The phase inversion technique was used to form PSCMS-g-DGEBA membranes. This effort also involves the designing of gold nanoparticles and its composite nanoparticles with polystyrene microspheres as matrix reinforcement. The nanoporous morphology was observed at lower filler content and there was formation of nanopattern at increased nanofiller content. The tensile strength was improved from 32.5 to 35.2 MPa with the increase in AuNPs-PSNPs loading from 0.1 to 1 wt%. The glass transition temperature was also enhanced from 132 to 159 °C. The membrane properties were measured via nanofiltration set-up. Higher pure water permeation flux, recovery, and salt rejection were measured for novel membranes. PSCMS-g-DGEBA/AuNPs-PSNPs membrane with 1 wt% loading showed flux of 2.01 mL cm−2 min−1 and salt rejection ratio of 70.4 %. Efficiency of the gold/polystyrene nanoparticles reinforced membranes for the removal of Hg2+ and Pb2 was found to be 99 %. Novel hybrid membranes possess fine characteristics to be utilized in industrial water treatment units.
Keywords: Nanofiltration; Poly(styrene-co-chloromethylstyrene); Epoxy; Phase inversion; Pure water flux

Agriculture is one of the several major sources of nitrate pollution, and therefore the EU Nitrate Directive, designed to decrease pollution, has been implemented. Point sources like septic systems and broken sewage systems also contribute to water pollution. Pollution of groundwater by nitrate from 19 shallow wells was studied in a typical agricultural region, middle Podravina, in northwest Croatia. The concentration of nitrate ranged from <0.1 to 367 mg/l in water from wells, and 29.8 % of 253 total samples were above maximum acceptable value of 50 mg/l (MAV). Among regions R1–R6, there was no statistically significant difference in nitrate concentrations (F = 1.98; p = 0.15) during the years 2002–2007. Average concentrations of nitrate in all 19 wells for all the analyzed years were between recommended limit value of 25 mg/l (RLV) and MAV except in 2002 (concentration was under RLV). The results of the repeated measures ANOVA showed statistically significant differences between the wells at the point source distance (proximity) of <10 m, compared to the wells at the point source distance of >20 m (F = 10.6; p < 0.001). Average annual concentrations of nitrate during the years studied are not statistically different, but interaction between proximity and years is statistically significant (F = 2.07; p = 0.04). Results of k-means clustering confirmed division into four clusters according to the pollution. Principal component analysis showed that there is only one significant factor, proximity, which explains 91.6 % of the total variability of nitrate. Differences in water quality were found as a result of different environmental factors. These results will contribute to the implementation of the Nitrate Directive in Croatia and the EU.
Keywords: Nitrate; Pollution; Point source; Water; Shallow well; Croatia

Evaluation of water quality index for River Sabarmati, Gujarat, India by Kosha A. Shah; Geeta S. Joshi (1349-1358).
An attempt has been made to develop water quality index (WQI), using six water quality parameters pH, dissolved oxygen, biochemical oxygen demand, electrical conductivity, nitrate nitrogen and total coliform measured at three different stations along the Sabarmati river basin from the year 2005 to 2008. Rating scale is developed based on the tolerance limits of inland waters and health point of view. Weighted arithmetic water quality index method was used to find WQI along the stretch of the river basin. It was observed from this study that the impact of human activity and sewage disposal in the river was severe on most of the parameters. The station located in highly urban area showed the worst water quality followed by the station located in moderately urban area and lastly station located in a moderately rural area. It was observed that the main cause of deterioration in water quality was due to the high anthropogenic activities, illegal discharge of sewage and industrial effluent, lack of proper sanitation, unprotected river sites and urban runoff.
Keywords: Water quality parameters; Water quality index; Rating scale; Weighted arithmetic mean method

Coalbed methane-produced water quality and its management options in Raniganj Basin, West Bengal, India by Vinod Atmaram Mendhe; Subhashree Mishra; Atul Kumar Varma; Awanindra Pratap Singh (1359-1367).
Coalbed methane (CBM) recovery is associated with production of large quantity of groundwater. The coal seams are depressurized by pumping of water for regular and consistent gas production. Usually, CBM operators need to pump >10 m3 of water per day from one well, which depends on the aquifer characteristics, drainage and recharge pattern. In India, 32 CBM blocks have been awarded for exploration and production, out of which six blocks are commercially producing methane gas at 0.5 million metric standard cubic feet per day. Large amount of water is being produced from CBM producing blocks, but no specific information or data are available for geochemical properties of CBM-produced water and its suitable disposal or utilization options for better management. CBM operators are in infancy and searching for the suitable solutions for optimal management of produced water. CBM- and mine-produced water needs to be handled considering its physical and geochemical assessment, because it may have environmental as well as long-term impact on aquifer. Investigations were carried out to evaluate geochemical and hydrogeological conditions of CBM blocks in Raniganj Basin. Totally, 15 water samples from CBM well head and nine water samples from mine disposal head were collected from Raniganj Basin. The chemical signature of produced water reveals high sodium and bicarbonate concentrations with low calcium and magnesium, and very low sulphate in CBM water. It is comprehend that CBM water is mainly of Na–HCO3 type and coal mine water is of Ca–Mg–SO4 and HCO3–Cl–SO4 type. The comparative studies are also carried out for CBM- and mine-produced water considering the geochemical properties, aquifer type, depth of occurrence and lithological formations. Suitable options like impounding, reverse osmosis, irrigation and industrial use after prerequisite treatments are suggested. However, use of this huge volume of CBM- and mine-produced water for irrigation or other beneficial purposes may require careful management based on water pH, EC, TDS, alkalinity, bicarbonate, sodium, fluoride, metals content and SAR values.
Keywords: CBM and coal mine water; Quality; Geochemical; Utilization and disposal options

The use of Moringa oleifera seed as a natural coagulant for wastewater treatment and heavy metals removal by Tan Chu Shan; Manaf Al Matar; Essam A. Makky; Eman N. Ali (1369-1376).
Moringa oleifera (MO) is a multipurpose tree with considerable potential and its cultivation is currently being actively promoted in many developing countries. Seeds of this tropical tree contain water-soluble, positively charged proteins that act as an effective coagulant for water and wastewater treatment. Based on this, water quality of “Sungai baluk” river was examined before and after the treatment using MO seed. MO seed exhibited high efficiency in the reduction and prevention of the bacterial growth in both wastewater and “Sungai baluk” river samples. The turbidity was removed up to 85–94% and dissolved oxygen (DO) was improved from 2.58 ± 0.01 to 4.00 ± 0.00 mg/L. The chemical oxygen demand (COD) and biological oxygen demand (BOD) were increased after the treatment from 99.5 ± 0.71 to 164.0 ± 2.83 mg/L for COD and from 48.00 ± 0.42 to 76.65 ± 2.33 mg/L for BOD, respectively. Nevertheless, there was no significant alteration of pH, conductivity, salinity and total dissolved solid after the treatment. Heavy metals such as Fe were fully eliminated, whereas Cu and Cd were successfully removed by up to 98%. The reduction of Pb was also achieved by up to 78.1%. Overall, 1% of MO seed cake was enough to remove heavy metals from the water samples. This preliminary laboratory result confirms the great potential of MO seed in wastewater treatment applications.
Keywords: Moringa oleifera ; Wastewater; Treatment; Dissolved oxygen; Turbidity; TDS; Heavy metals; Antibacterial assay

Remote sensing and GIS tools have broadly helped hydrogeologists to delineate the groundwater prospective zones for watershed development and management. The origin, movement and existence of groundwater depends on several factors such as slope, drainage density, land use, geology, lineament density and geomorphology. Based on these, the mapping and identification of groundwater potential zones were carried out in a part of Nalgonda district, Telangana, India. The regions were categorised as high, moderate and low groundwater potential, and they were validated with the groundwater levels and yield of wells located in the corresponding zones. Extensive possibility for watershed development is possible in 41 % of the total 724 km2 and 46 % of the area offers moderate options. Any groundwater management project implemented in these favourable areas will bring maximum benefit. Similar studies should be considered necessary before designing a water resource development activity as it will reduce the cost on detailed field visits which are time-consuming.
Keywords: Groundwater potential zones; Overlay analysis; Thematic layers; Nalgonda; Telangana; India

Water resource is of great significance to the survival and development of human. However, the water resource system in karst regions is sensitive to external interference owing to the special geological processes which cause soil impoverishment, severe rocky desertification and large topographic height difference. Therefore, evaluating the sustainability of the water resource in karst regions is beneficial to reasonably use and protect water resource. This paper puts forward to evaluate the water resource from four aspects, including water resources system, water requirement system, ecosystem and social economic system. Moreover, on this basis, 18 evaluation indexes were selected to construct the sustainability evaluation index system and method. This method was used to evaluate the sustainability of the water resource in the typical karst region—Zunyi, Guizhou province, China, and was verified according to the actual situation in the research area. All these provide reference for the evaluation of the sustainability of the water resource in similar regions.
Keywords: Karst region; Water resource; Evaluation index system; Sustainability; Evaluation

Amount of water needed to save 1 m3 of water: life cycle assessment of a flow regulator by Markus Berger; Michael Söchtig; Christoph Weis; Matthias Finkbeiner (1399-1407).
Water saving devices in the sanitary equipment, such as flow regulators, are assumed to be environmentally advantageous even though their environmental benefit has never been compared to the environmental burden caused during their production und disposal. Therefore, a life cycle assessment according to ISO 14044 has been conducted to identify and quantify the environmental effects throughout the lifespan of a flow regulator. The analysis comprises the production of materials, manufacturing of components at suppliers, the assembly at NEOPERL®, all transports, savings of water and thermal energy during use as well as waste incineration including energy recovery in the end-of-life stage. Results show that the production of one flow regulator causes 0.12 MJ primary energy demand, a global warming potential of 5.9 g CO2-equivalent, and a water consumption of 30.3 ml. On the other hand, during a use of 10 years, it saves 19,231 MJ primary energy, 1223 kg CO2-equivalent, and avoids a water consumption of 790 l (166,200 l water use). Since local impacts of water consumption are more relevant than volumes, consequences of water consumption have been analyzed using recently developed impact assessment models. Accordingly, the production of a flow regulator causes 8.5 ml freshwater depletion, 1.4 × 10−13 disability adjusted life years, and 4.8 × 10−6 potentially disappeared fractions of species m2 a. Even though avoided environmental impacts resulting from water savings highly depend on the region where the flow regulator is used, the analysis has shown that environmental benefits are at least 15,000 times higher than impacts caused during the production.
Keywords: Life cycle assessment; Water footprint; Climate change; Primary energy demand; Flow regulator; NEOPERL®

Synthesis of nanoscale zerovalent manganese (nZVMn) by chemical reduction was carried out in a single pot system under inert environment. nZVMn was characterized using a combination of analytical techniques: Ultraviolet–Visible Spectroscopy, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray, BET surface area and Point of Zero Charge. The adsorption physicochemical factors: pH, contact time, adsorbent dose, agitation speed, initial copper ion concentration and temperature were optimized. The kinetic data fitted better to Pseudo second-order, Elovich, fractional power and intraparticle diffusion models and their validity was tested by three statistical models: sum of square error, Chi-square (χ 2) and normalized standard deviation (Δq). Seven of the two-parameter isotherm models [Freundlich, Langmuir, Temkin, Dubinin–Kaganer–Raduskevich (DKR), Halsey, Harkin–Jura and Flory–Huggins] were used to analyse the equilibrium adsorption data. The Langmuir monolayer adsorption capacity (Q max = 181.818 mg/g) obtained is greater than other those of nano-adsorbents utilized in adsorption of copper ions. The equilibrium adsorption data were better described by Langmuir, Freundlich, Temkin, DKR and Halsey isotherm models considering their coefficient of regression (R 2 > 0.90). The values of the thermodynamic parameters: standard enthalpy change ∆H° (+50.27848 kJ mol−1), standard entropy change ∆S° (203.5724 J mol−1 K−1) and the Gibbs free energy change ∆G° revealed that the adsorption process was feasible, spontaneous, and endothermic in nature. The performance of this novel nanoscale zerovalent manganese (nZVMn) suggested that it has a great potential for effective removal of copper ions from aqueous solution.
Keywords: Manganese nanoparticles; Copper; Characterization; Kinetics; Isotherm; Thermodynamics

Hydrochemical characteristics and quality assessment of groundwater along the Manavalakurichi coast, Tamil Nadu, India by Y. Srinivas; T. B. Aghil; D. Hudson Oliver; C. Nithya Nair; N. Chandrasekar (1429-1438).
The present study was carried out to find the groundwater quality of coastal aquifer along Manavalakurichi coast. For this study, a total of 30 groundwater samples were collected randomly from open wells and borewells. The concentration of major ions and other geochemical parameters in the groundwater were analyzed in the laboratory by adopting standard procedures suggested by the American Public Health Association. The order of the dominant cations in the study area was found to be Na+ > Ca2+ > Mg2+ > K+, whereas the sequence of dominant anions was $${ ext{Cl}}^{ - } > { ext{HCO}}_{3}^{ - } > { ext{SO}}_{4}^{2 - }$$ Cl - > HCO 3 - > SO 4 2 - . The hydrogeochemical facies of the groundwater samples were studied by constructing piper trilinear diagram which revealed the evidence of saltwater intrusion into the study area. The obtained geochemical parameters were compared with the standard permissible limits suggested by the World Health Organization and Indian Standard Institution to determine the drinking water quality in the study area. The analysis suggests that the groundwater from the wells W25 and W26 is unsuitable for drinking. The suitability of groundwater for irrigation was studied by calculating percent sodium, sodium absorption ratio and residual sodium carbonate values. The Wilcox and USSL plots were also prepared. It was found that the groundwater from the stations W1, W25 and W26 is unfit for irrigation. The Gibbs plots were also sketched to study the mechanisms controlling the geochemical composition of groundwater in the study area.
Keywords: Groundwater; Quality; Assessment; Tamil Nadu; India

Coagulation–flocculation–sedimentation processes for treating three levels of bentonite synthetic turbid water using date seeds (DS) and alum (A) coagulants were investigated in the previous research work. In the current research, the same experimental results were used to adopt a new approach on a basis of using coagulation rate constant as an investigating parameter to identify optimum doses of these coagulants. Moreover, the performance of these coagulants to meet (WHO) turbidity standard was assessed by introducing a new evaluating criterion in terms of critical coagulation rate constant (kc). Coagulation rate constants (k2) were mathematically calculated in second order form of coagulation process for each coagulant. The maximum (k2) values corresponded to doses, which were obviously to be considered as optimum doses. The proposed criterion to assess the performance of coagulation process of these coagulants was based on the mathematical representation of (WHO) turbidity guidelines in second order form of coagulation process stated that (k2) for each coagulant should be ≥ (kc) for each level of synthetic turbid water. For all tested turbid water, DS coagulant could not satisfy it. While, A coagulant could satisfy it. The results obtained in the present research are exactly in agreement with the previous published results in terms of finding optimum doses for each coagulant and assessing their performances. On the whole, it is recommended considering coagulation rate constant to be a new approach as an indicator for investigating optimum doses and critical coagulation rate constant to be a new evaluating criterion to assess coagulants’ performance.
Keywords: Coagulation rate constant; Kinetics modeling; Coagulants’ performance; Turbidity removal

Removal of arsenic from drinking water using rice husk by Zunaira Asif; Zhi Chen (1449-1458).
Rice husk adsorption column method has proved to be a promising solution for arsenic (As) removal over the other conventional methods. The present work investigates the potential of raw rice husk as an adsorbent for the removal of arsenic [As(V)] from drinking water. Effects of various operating parameters such as diameter of column, bed height, flow rate, initial arsenic feed concentration and particle size were investigated using continuous fixed bed column to check the removal efficiency of arsenic. This method shows maximum removal of As, i.e., 90.7 % under the following conditions: rice husk amount 42.5 g; 7 mL/min flow rate in 5 cm diameter column at the bed height of 28 cm for 15 ppb inlet feed concentration. Removal efficiency was increased from 83.4 to 90.7 % by reducing the particle size from 1.18 mm to 710 µm for 15 ppb concentration. Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior. The effect of different operating parameters on the column adsorption was determined using breakthrough curves. In the present study, three kinetic models Adam-Bohart, Thomas and Yoon–Nelson were applied to find out the saturated concentration, fixed bed adsorption capacity and time required for 50 % adsorbate breakthrough, respectively. At the end, solidification was done for disposal of rice husk.
Keywords: Adsorption; Arsenic; Rice husk; Kinetic models; Fixed bed column

Removal of phenol from aqueous solution using rice straw as adsorbent by Nandita Sarker; A. N. M. Fakhruddin (1459-1465).
Phenol is an environmental pollutant; the present study was conducted to examine the adsorption of phenol by rice straw. For this purpose raw (untreated), physically treated (boiled and dried) and thermally treated (heated at 230 °C for 3 h to produce ash) rice straw were selected to determine phenol removal efficiency at different contact times and adsorbent dosages for 1 and <1 mm rice straw particles. Residual phenol concentrations were determined by colorimetric method. Highest 84 % of phenol removal was observed for thermally treated <1 mm rice straw particle. Equilibrium time was more than four hour. Percentage of removal of phenol increased as the adsorbent dose increase. The removal efficiency increase in the order of: raw rice straw < physically treated < thermally treated (ash) rice straw. Langmuir and Freundlich isotherm was developed for 1 and <1 mm particle size of thermally (ash) treated rice straw. Freundlich isotherm best fit the equilibrium data for 1 mm thermally treated rice straw. The results showed that thermally treated rice straw (ash) can be developed as a potential adsorbent for phenol removal from aqueous solution.
Keywords: Adsorption; Phenol; Rice straw; Equilibrium; Isotherm

Fluoride occurrence in the groundwater in a coastal region of Andhra Pradesh, India by N. Subba Rao; P. Surya Rao; A. Dinakar; P. V. Nageswara Rao; Deepali Marghade (1467-1478).
Fluoride (F) content varies from 0.60 to 1.80 mg/L in the coastal region between Chirala and Ongole of Andhra Pradesh, India. It exceeds the threshold limit of 1.20 mg/L in 20 % of the total groundwater samples. The aim of the present study is to assess the controlling factors of F content. The study area experiences a dry climate and is underlain by Charnockite Group of rocks over which the river and coastal alluvium occur. The results of the study identify the four factors that control the high F content. First one is related to alkalinity, leading to active dissolution and leaching of F-bearing minerals, which supports the positive correlation of F with pH and HCO3 . A longer water residence time in the clays is the second factor, which activates not only solubility and dissolution of F-bearing minerals, but also anion exchange between F and OH. Third factor is a result of higher Na+ due to impact of saline water, ion exchange between Na+ and Ca2+, and precipitation of CaCO3. This reduces the Ca2+ content, causing dissolution of CaF2 to maintain the chemical equilibria, which is supported by positive correlation between Na2+ and F. The influence of anthropogenic activities is the last factor, which acts as an additional source of F. Thus, the shallow groundwater shows higher content of F and the hydrogeochemical facies also support this hypothesis. The study suggests the remedial measures to reduce the F content.
Keywords: Fluoride; Groundwater; Coastal region; Prakasam district; Andhra Pradesh; India

The objective of the study is to reveal the seasonal variations in the groundwater quality with respect to heavy metal contamination. To get the extent of the heavy metals contamination, groundwater samples were collected from 45 different locations in and around Goa mining area during the monsoon and post-monsoon seasons. The concentration of heavy metals, such as lead, copper, manganese, zinc, cadmium, iron, and chromium, were determined using atomic absorption spectrophotometer. Most of the samples were found within limit except for Fe content during the monsoon season at two sampling locations which is above desirable limit, i.e., 300 µg/L as per Indian drinking water standard. The data generated were used to calculate the heavy metal pollution index (HPI) for groundwater. The mean values of HPI were 1.5 in the monsoon season and 2.1 in the post-monsoon season, and these values are well below the critical index limit of 100.
Keywords: Groundwater; Heavy metal; Pollution index; Seasonal variation; Goa

Combining rainfall data from rain gauges and TRMM in hydrological modelling of Laotian data-sparse basins by Xing Liu; Fa Ming Liu; Xiao Xia Wang; Xiao Dong Li; Yu Yan Fan; Shi Xiang Cai; Tian Qi Ao (1487-1496).
At present, prediction of streamflow simulation in data-sparse basins of the South East Asia is a challenging task due to the absence of reliable ground-based rainfall information, while satellite-based rainfall estimates are immensely useful to improve our understanding of spatio-temporal variation of rainfall, particularly for data-sparse basins. In this study the TRMM 3B42 V7 and its bias-corrected data were, respectively, used to drive a physically based distributed hydrological model BTOPMC to perform daily streamflow simulations in Nam Khan River and Nam Like River basins during the years from 2000 to 2004 so as to investigate the potential use of the TRMM in complementing rain gauge data in hydrological modelling of data-sparse basins. The results show that although larger difference exists in the high streamflow process and the low streamflow process, the daily simulations fed with TRMM precipitation data could basically reflect the daily streamflow processes at the four stations and determine the time to peak. Furthermore, the calibrated parameters in the Nam Khan River basin are more suitable than that in the Nam Like River basin. By comparing the two precipitation data, it indicates that the integration of TRMM precipitation data and rain gauge data have a promising prospect on the hydrological process simulation in data-sparse basin.
Keywords: TRMM satellite precipitation; Distributed hydrological model; Laotian data-sparse basins; Streamflow simulation

The author’s present study was carried out for a period of 3 years from 2010 to 2013 to itemize the various physico-chemical parameters, irrigation water quality parameters and heavy metals in Champavathi River waters at Andra reservoir and Denkada anicut. Water samples were collected from the chosen sampling stations of the two reservoirs for every 4 months and analyzed as per APHA standard methods. The results obtained were compared with IS 10500 standards and found to be well within the prescribed values. Though the obtained values were well within the prescribed standard values, it was found that the water quality index, concentration of certain parameters such as calcium, magnesium, sodium and potassium of the waters of Andra reservoir are higher than that of the Denkada anicut, and the concentration of nitrite was found to be higher in the water sample analyzed from Denkada anicut. Except silicon, all the other metals were found to be below the detection limits in the two reservoir waters. The reasons for the same were probed by the authors in the presented study. From the analysis reports, it was found that the water analyzed from the two reservoirs was fit for irrigation, agriculture, industrial and domestic purposes.
Keywords: Water quality index; Physico-chemical characterization; Andra reservoir; Denkada anicut; Vizianagaram; Irrigation projects

Prioritization of watershed through morphometric parameters: a PCA-based approach by Sarita Gajbhiye Meshram; S. K. Sharma (1505-1519).
Remote sensing (RS) and Geographic Information Systems (GIS) techniques have become very important these days as they aid planners and decision makers to make effective and correct decisions and designs. Principal Component Analysis (PCA) involves a mathematical procedure that transforms a number of (possibly) correlated variables into a (smaller) number of uncorrelated variables. It reduces the dimensionality of the data set and identifies a new meaningful underlying variable. Morphometric analysis and prioritization of the sub-watersheds of Shakkar River Catchment, Narsinghpur district in Madhya Pradesh State, India, is carried out using RS and GIS techniques as discussed in Gajbhiye et al. (Appl Water Sci 4(1):51–61, 2013b). In this study we apply PCA technique in Shakkar River Catchment for redundancy of morphometric parameters and find the more effective parameters for prioritization of the watershed and discuss the comparison between Gajbhiye et al. (Appl Water Sci 4(1):51–61, 2013b) and the present prioritization scheme.
Keywords: Watershed; GIS; Remote sensing; Morphometric analysis; Prioritization; Principal component analysis

The backwater of Veli-Akkulam, adjoining the Arabian Sea in the south-west part of Indian Peninsula, is a coastal wetland system and forms an integral part of the local ecosystem. In addition to the usual marine interactions, this water body is subjected to anthropogenic interference due to their proximity to the Thiruvananthapuram City urban agglomeration. This paper showcases how an urban agglomeration alters wetland system located within a tropical monsoonal environment. Water samples from this lake together with different feeder streams reveal that the lake is under the threat to eutrophication. A spatio-temporal analysis has shown that the lake and adjacent wetlands are shrinking in a fast pace. Over a period of about seven decades, the lake has shrunk by 28.05 % and the wetlands by 37.81 %. And hence, there is a pressing requirement of eco-management practices to be adopted to protect this lake.
Keywords: Veli-Akkulam Lake; Hydrogeochemistry; Spatio-temporal variation; Eutrophication

Water quality modeling for urban reach of Yamuna river, India (1999–2009), using QUAL2Kw by Deepshikha Sharma; Arun Kansal; Greg Pelletier (1535-1559).
The study was to characterize and understand the water quality of the river Yamuna in Delhi (India) prior to an efficient restoration plan. A combination of collection of monitored data, mathematical modeling, sensitivity, and uncertainty analysis has been done using the QUAL2Kw, a river quality model. The model was applied to simulate DO, BOD, total coliform, and total nitrogen at four monitoring stations, namely Palla, Old Delhi Railway Bridge, Nizamuddin, and Okhla for 10 years (October 1999–June 2009) excluding the monsoon seasons (July–September). The study period was divided into two parts: monthly average data from October 1999–June 2004 (45 months) were used to calibrate the model and monthly average data from October 2005–June 2009 (45 months) were used to validate the model. The R2 for CBODf and TN lies within the range of 0.53–0.75 and 0.68–0.83, respectively. This shows that the model has given satisfactory results in terms of R2 for CBODf, TN, and TC. Sensitivity analysis showed that DO, CBODf, TN, and TC predictions are highly sensitive toward headwater flow and point source flow and quality. Uncertainty analysis using Monte Carlo showed that the input data have been simulated in accordance with the prevalent river conditions.
Keywords: QUAL2Kw; Calibration; Validation; Sensitivity; Uncertainty analysis

Management of a water distribution network by coupling GIS and hydraulic modeling: a case study of Chetouane in Algeria by Chérifa Abdelbaki; Mohamed Mouâd Benchaib; Salim Benziada; Hacène Mahmoudi; Mattheus Goosen (1561-1567).
For more effective management of water distribution network in an arid region, Mapinfo GIS (8.0) software was coupled with a hydraulic model (EPANET 2.0) and applied to a case study region, Chetouane, situated in the north-west of Algeria. The area is characterized not only by water scarcity but also by poor water management practices. The results showed that a combination of GIS and modeling permits network operators to better analyze malfunctions with a resulting more rapid response as well as facilitating in an improved understanding of the work performed on the network. The grouping of GIS and modeling as an operating tool allows managers to diagnosis a network, to study solutions of problems and to predict future situations. The later can assist them in making informed decisions to ensure an acceptable performance level for optimal network operation.
Keywords: Water distribution network; GIS; Database; Modeling; EPANET