Characteristics Of River Water Research Articles

Sources and Chemical Weathering Implications of Strontium and Hydrochemistry in an Inland Alpine Permafrost Basin

AbstractThe hydrochemical characteristics of river water are influenced by a multitude of factors, reflecting the surrounding geographical environment. The Shaliu River, located in the northeastern Tibetan Plateau (TP), serves as a typical inland alpine permafrost watershed. In this study, we compiled data on dissolved strontium (Sr) concentration, 87Sr/86Sr isotopic, and hydrochemical profiles from the Shaliu River during the ablation period (May–October). Additionally, we gathered information on the Sr concentration and 87Sr/86Sr in the sediment of the river. The pattern of spatial heterogeneity in observed strontium (Sr) compositions can largely be attributed to lithological characteristics encountered at different locations along the river. The chemical components of Sr in the waters are derived from a combination of carbonate and silicate materials, with carbonates contributing between 69% and 81% and silicates contributing 19%–31%. The annual dissolved Sr flux is estimated to be 132 t/a. In addition to the influence of lithology and weathering processes, we propose that freeze‐thaw cycles within the permafrost layer may significantly affect the chemical mass flux in alpine permafrost watersheds because they generate substantial amounts of loose and easily erodible materials. Climate warming may further intensify the weathering processes in these watersheds, potentially leading to an increase in the Sr flux. This study is crucial for developing a comprehensive understanding of the geochemical composition of dissolved solutes in alpine permafrost regions, as well as for identifying the factors that regulate river water chemistry.

Effects of landscape structure on river water characteristics: a multi-scale analysis

Effects of landscape structure on river water characteristics: a multi-scale analysis

Modeling the Effects of River Inflow Dynamics on the Deep Layers of Lake Biwa, Japan

Climate change-induced extreme weather events, including prolonged droughts and intense rainfall, exert a significant influence on river inflows. These inflows act as vital conduits for nutrient transport, water quality modulation, and the regulation of thermal dynamics in lakes and oceans. In this context, this study conducts a comprehensive examination of the multifaceted effects stemming from river water characteristics, snowmelt water influence, and shifts in precipitation patterns on the stratification dynamics of Lake Biwa in Japan. To facilitate these investigations, a hydrodynamic model was developed to simulate thermal stratification in Lake Biwa. The results demonstrate that an increase in precipitation and river water flow, specifically doubling these factors, leads to noticeable cooling of the lake’s surface layer and a consequent destabilization of stratification during the stratification period. Conversely, halving these factors stabilizes stratification. Furthermore, elevating river water temperature by 5 °C raises water temperature near the upper thermocline, encouraging vertical mixing within the surface layer. Conversely, a 5 °C decrease induces significant temperature fluctuations and an unstable stratification extending from the surface to deeper layers. Notably, the spatial variance in water temperature within Lake Biwa is profoundly influenced by fluctuations in river water temperature. This study underscores the critical importance of considering river plumes in the study of material circulation, stratification dynamics, and ecological well-being in lakes and oceans. Given the mounting concerns related to eutrophication and the prevalence of anoxia in aquatic ecosystems, this research provides invaluable insights into assessing the impacts of river plumes on Lake Biwa’s stratification structure and seasonal dynamics.

Spatial characteristics and controlling indicators of major hydrochemical ions in rivers within coal-grain composite areas via multivariate statistical and isotope analysis methods

The spatial variability of river hydrochemistry in coal-grain composite areas is influenced by natural processes and human activities. However, there is little information thus far on the hydrochemical characteristics of river water and the spatial variability in coal–grain composite areas under the influence of multiple superimposed effects. In this study, river water samples (n = 31) were collected in a coal-grain composite area in the northern plain of Anhui Province (China). The main hydrochemical ions and stable isotopes (δ2H-H2O, δ18O-H2O, δ34S-SO42- and δ18O-SO42-) were then investigated. The objective was to analyze the spatial characteristics and controlling indicators of the main hydrochemical ions via multivariate statistical and isotope analysis methods. The values of δ34S-SO42- and δ18O-SO42- in river water ranged from 7.5 ‰ to 17.5 ‰ and from 4.4 ‰ to 10.7 ‰, respectively. According to the clustering analysis method, the river water samples were divided into two groups. Bayesian mixed model analysis indicated that the sources of SO42- in river water mainly included soil sulfate and mine drainage, with contribution proportions of 74.0 ± 3.1 % and 18.4 ± 4.1 % in River Group I, respectively, and 77.2 ± 3.0 % and 11.1 ± 5.1 % in River Group II, respectively. These results suggested that the controlling indicators of the spatial distribution characteristics of river hydrochemistry were natural processes (water–rock interactions) and human activities (coal mining, manure release and sewage discharge). The results could provide valuable information for regional water resource management, development, and similar coal–grain composite areas elsewhere.

New model of long-term changes in spatiotemporal patterns of water quality across Shatt-Al-Arab River by applying GIS technique, from 1976 to 2020

PurposeUsing a combination of the geographical information system (GIS) and the Canadian water quality index (WQI), the current study sought to provide a long-term general assessment of the water quality of the Shatt Al-Arab River (SAAR), focusing on its suitability for living organisms. Likewise, SPSS statistics was used to develop a nonlinear WQI regression model for the study area.Design/methodology/approachThe study required four decades of data collection on some environmental characteristics of river water. After that, calculate the WQI and conduct the spatial analysis. Eight variables in total, including water temperature, dissolved oxygen, potential hydrogen ions, electrical conductivity (EC), biological oxygen demand, turbidity, nitrate and phosphate, were chosen to calculate the WQI.FindingsThroughout the study periods, the WQI values varied from 55.2 to 79.83, falling into the categories of four (marginal) and three (fair), with the sixth period (2007–2008) showing the most decline. The present research demonstrated that the high concentration of phosphates, the high EC values, and minor changes in the other environmental factors are the major causes of the decline in water quality. The variations in ecological variables' overlap are a senior contributor to changes in water quality in general. Notably, using GIS in conjunction with the WQI has shown to be very effective in reducing the time and effort spent on investigating water quality while obtaining precise findings and information at the lowest possible expense. Calibration and validation of the developed model showed that this model had a perfect estimate of the WQI value. Due to its flexibility and impartiality, this study recommends using the proposed model to estimate and predict the WQI in the study area.Originality/valueEven though the water quality of the SAAR has been the subject of numerous studies, this is the only long-term investigation that has been done to evaluate and predict its water quality.

ECOLOGICAL EFFECTS OF BELIK RIVER HYDRAULIC CHARACTERISTICS ON PERIPHYTON COMMUNITY AS WATER QUALITY BIOINDICATOR

ARTICLE HIGLIGHTS- Differences in river hydraulic characteristics affect ecological river health- The influence of flooding on the dynamics of physical and chemical characteristics of river water- Life strategy, adaptation of periphyton to environmental changes- Development of green infrastructure for river conservationABSTRACTBelik River is one of the urban rivers in the Special Region of Yogyakarta which has hydrological problems both in quantity and quality. This triggered the construction of various types of channel modifications. This study aimed to identify water quality and the ecological effects of channel modifications based on the presence of periphyton communities as bioindicators. Sampling was carried out in January 2021 and March 2021. Samples were taken at 4 sampling sites with different channel characteristics with 3 repetitions at each location. The physico-chemical parameters measured included pH, detergent, nitrate, sulfate, total phosphate, TSS, TDS, DO, CO2, water temperature, depth, transparency, discharge, and current velocity. The results showed that the abundance of periphyton in January 2021 was higher than in March 2021. In January 2021 there were found 91 periphyton species dominated by Nitzschia improvisa, Nitzschia terricola, and Nitzschia philippinarum. Meanwhile, in March 2021 there were found 61 species of periphyton dominated by Nitzschia improvisa. Based on the results of Canonical Correlation Analysis (CCA), it was shown that in general the distribution and abundance of periphyton in the Belik River were influenced by CO2, total phosphate, discharge, DO, nitrate, TSS, and depth. The Shannon Wiener Diversity Index showed that water quality in January 2021 has decreased in March 2021. From the cluster analysis, it is known that there are differences in water quality and abundance of periphyton in the four types of river channels. It can be concluded that differences in hydraulic characteristics affected water quality and the ecological health of Belik River.

Assessment of river water quality improvement due to riverbank filtration (RBF) mechanism

Riverbank filtration (RBF) is a natural process where river water is induced to flow through riverbed soils to pumping wells located on the banks. It is a well-established and proven natural water treatment technology by having a series of physical and chemical processes during subsurface passage. This paper aims at the measurement of physical and chemical characteristics of river water and groundwater from riverbank filtration wells at Kg. Jenderam Hilir, Selangor and to assess the effectiveness of riverbank filtration through Water Quality Index (WQI) for both river water and groundwater. The riverbank filtration is able to improve quality of water such as reducing the turbidity to 0 NTU, Chemical Oxygen Demand (COD) to 3.67 mg/l, Suspended Solids (SS) to 6.33 mg/l and several other contents that existed in the river. In addition, the effectiveness of RBF is also proven based on the improvement of Water Quality Index (WQI) for Langat river from Class IV to Class III.

The Quality of Yıldız River Water and Determining Trace Elements by Liquid-Liquid Micro-Extraction Analytical Method

The present study was carried out between September 2019 and March 2020 in Yıldız River, which is located within the borders of the Yıldızeli district of Sivas province and used for agricultural irrigation purposes, to determine the chemical characteristics of river water and the trace elements. Water’s alkalinity, chemical oxygen demand (COD), chloride (Cl-), calcium (Ca2+), total hardness, total phosphate (PO4-P), dissolved reactive phosphate (SRP), ammonium nitrogen (NH4-N), nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N), soluble reactive silica (SiO2-Si) concentrations, as well as trace elements (ferrous, lead, cadmium). Moreover, during the sampling process, also the water temperature, dissolved oxygen, conductivity, pH, and total dissolved solids measurements were performed. Before using the flame atomic absorption spectrometer (FAAS) in determining the Fe, Pb, and Cd in water samples, a simple, environment-friendly, and new ultrasonic liquid-liquid micro-extraction method was suggested. Several parameters (pH, ionic fluid amount, dispersive solvent volume, and temperature) influencing the performance of micro-extraction were optimized. Under the optimized conditions, the detection thresholds for Fe (II), Pb (II), and Cd (II) were found to be 0.6, 0.15, and 1.5 μg L-1, respectively.

Land Use and Land Cover Shape River Water Quality at a Continental Caribbean Land-Ocean Interface

Land use and land cover (LULC) can significantly alter river water, which can in turn have important impacts on downstream coastal ecosystems by delivering nutrients that promote marine eutrophication and hypoxia. Well-documented in temperate systems, less is known about the way land cover relates to water quality in low-lying coastal zones in the tropics. Here we evaluate the catchment LULC and the physical and chemical characteristics of six rivers that contribute flow into a seasonally hypoxic tropical bay in Bocas del Toro, Panama. From July 2019 to March 2020, we routinely surveyed eight physical and chemical characteristics (temperature, specific conductivity, salinity, pH, dissolved oxygen (DO), nitrate and nitrite, ammonium, and phosphate). Our goals were to determine how these physical and chemical characteristics of the rivers reflect the LULC, to compare the water quality of the focal rivers to rivers across Panama, and to discuss the potential impacts of river discharge in the Bay. Overall, we found that the six focal rivers have significantly different river water characteristics that can be linked to catchment LULC and that water quality of rivers 10 s of kilometers apart could differ drastically. Two focal catchments dominated by pristine peat swamp vegetation in San San Pond Sak, showed characteristics typical of blackwater rivers, with low pH, dissolved oxygen, and nutrients. The remaining four catchments were largely mountainous with >50% forest cover. In these rivers, variation in nutrient concentrations were associated with percent urbanization. Comparisons across Panamanian rivers covered in a national survey to our focal rivers shows that saltwater intrusions and low DO of coastal swamp rivers may result in their classification by a standardized water quality index as having slightly contaminated water quality, despite this being their natural state. Examination of deforestation over the last 20 years, show that changes were <10% in the focal catchments, were larger in the small mountainous catchments and suggest that in the past 20 years the physical and chemical characteristics of river water that contributes to Almirante Bay may have shifted slightly in response to these moderate land use changes. (See supplementary information for Spanish-language abstract).

Relationship between macrobenthos and abiotic characteristics of river Alaknanda in a stretch from Chamoli to Devprayag in Garhwal Himalayan region of Uttarakhand, India

Macrobenthos is the best water quality indicator for ecosystem health assessment. The present study aimed to examine the interrelationship between macrobenthos and different water quality parameters of the river Alaknanda at Garhwal Himalaya. Four demarcated sampling zones viz. zone-A (Chamoli to Nandprayag), zone-B (Karanprayag to Rudraprayag), zone-C (Rudraprayag to Srinagar) and zone-D (Srinagar to Devprayag) were taken from its approximately 170 km long stretch during 2016-2018. River water characteristics were analyzed for the important parameters viz. substratum, water temperature (WT), water velocity, pH, electrical conductivity (EC), total dissolved solids (TDS), calcium (Ca), and magnesium (Mg) using standard methods. The results indicated that the river water velocity was the highest 1.02 m/s at zone-C, TDS of 114.19 mgl-1 was maximum at zone-A ; and Ca and Mg were recorded highest 23.17 mgl-1 and 5.44 mgl-1 at zone-A and zone-B, respectively. All abiotic parameters (pH, EC, TDS, DO, Ca and Mg) were recorded to be below BIS/WHO limits. A total of 27 macrobenthos taxa belonging to the five orders such as Coleoptera (6 ind./m2), Diptera (5 ind./m2), Ephemeroptera (8 ind./m2), Hemiptera (4 ind./m2), and Odonata (4 ind./m2) were recorded. Macrobenthos represented an important relationship between the water current and water temperature. The lowest number was reported at zone-C due to the river's high water velocity (1.02 m/s). The changes like biota loss, presence of some pollution indicator species (Cloeon sp., Bateis sp., Emphemera sp.) at zone-C, in sediment structure of habitat were due to the anthropogenic activities on the riverbank of different zones. The study will help in the conservation of macrobenthos diversity of the river Alaknanda.

Tracking spatio-temporal dynamics of fluorescence characteristics of Huangpu River, China by parallel factor analysis: Correlation with disinfection by-product precursor and pesticide level variations

The components and characteristics of dissolved organic matter (DOM), the main precursor of toxic disinfection by-products (DBPs), have attracted increasing attention in water sources. In this study, fluorescence excitation-emission matrix (EEM) coupled with parallel factor (PARAFAC) analysis was used to investigate the DOM fluorescence characteristics of river water along the Huangpu River, China. Four fluorescence components were identified, including two protein-like components (C1 and C2) and two humic-like components (C3 and C4). The fluorescence characteristics showed spatial and temporal variations with the highest total fluorescence intensities observed in autumn, and the increased relative abundance of humic-like substance in the metropolitan area of Shanghai. Fluorescence index and biological index indicated that the DOM of Huangpu River water had both terrestrial and microbial origins and mainly autochthonous characteristic. Moreover, the formation potentials (FPs) of DBP for Huangpu River water were determined, and trihalomethanes were the predominant species formed in all samples. The correlation analysis further showed that PARAFAC C4 (microbial humic-like fluorescence) significantly correlated with the FP of N-DBPs, providing an insight for drinking water treatment to control specific DBPs precursor. In addition, the humic-like components also correlated with the concentrations of triazole and organophosphate pesticides detected in the Huangpu River. These results indicated that fluorescence-PARAFAC analysis is a promising tool to assess the DBPFPs and pesticide occurrence in surface waters.

Calculating groundwater mixing ratios in multi-aquifers based on statistical methods: a case study

Abstract Samples of river water and groundwater from Quaternary (QA), sandstone (SA), Taiyuan formation (TA), and Ordovician limestone (OA) aquifers in the Suxian coal-mining district, Anhui Province, China were collected. Their physicochemical properties, and major ion and isotopic compositions were determined. The samples were alkaline, with pH values exceeding 8, and the total dissolved solids concentrations depended on the water source. The δD and δ18O contents were highest in the river water samples and lowest in the SA groundwater. The isotopic characteristics of the QA and OA groundwaters suggest recharge by rainfall and surface water. The isotopic characteristics of river water were controlled mainly by evaporation. Water–rock interactions, the flow rate, and the main water sources were the most important influences on groundwaters in QA, OA, and TA, but the properties of SA groundwater were controlled by static reserves. Two discriminant functions, explaining more than 98.2% of the total variances, indicated that QA, TA, and OA were hydraulically connected. Three groundwater sources were identified as end-members, and a conceptual model was established to calculate water mixing ratios.

Assessment of physico-chemical characteristics of river water emphasizing tannery industrial park: a case study of Dhaleshwari River, Bangladesh.

Pollution of industry-adjacent surface water bodies become a major environmental concern in Bangladesh recently. Therefore, this study aimed to elaborate assessment of physico-chemical characteristics of the Dhaleshwari River (the adjacent river of newly shifted tannery industrial park) and also the discharged effluent from the central effluent treatment plant (CETP) considering both seasonal and spatial variations. Among the examined 30 water quality parameters (including 11 heavy metals), only TDS, Cl-, NO3-N, EC, Cu, Zn, Cd, and Ni met the standards for discharged wastewater from industrial units into inland surface water set by Bangladesh government. This indicated that the CETP is not fully and/or effectively functioning. Out of 19 parameters (excluding heavy metal), 14 parameters exceeded the Bangladesh standard for drinking water quality either spatially or seasonally. The river water quality indicated slowly biodegradable capacity with algal bloom risk. The concentrations of the studied heavy metals in the river water followed a decreasing order of Ca > K > Mg > Na > Fe > Cr > Pb > Ni > Cu > Zn > Cd, and Cr concentration in the winter season exceeded the standard values. The concentrations of other heavy metals met the quality standard that indicated still the river is capable to self-purify. Furthermore, strong (p < 0.01) and significant (p < 0.05) correlation were observed among the quality parameters in river water. This study suggested that the efficiency of the existing CETP needs to be enhanced, and the proper operation and maintenance are required to meet the desired discharge standard quality. Also, all the unauthorized wastewater outfalls from tanneries must be closed to save the Dhaleshwari River.

Physico-chemical parameters and culturable yeast diversity in surface water: a consequence of pollution

Rivers in the North West Province (NWP) of South Africa are polluted by various anthropogenic activities that are associated with agricultural, domestic, industrial, and mining activities. Pollutants and effluent resulting from these activities impact the physico-chemical and biological characteristics of river water. More particularly, domestic and agricultural pollution has been associated with the occurrence of pathogenic yeast species in water. The aim of this study was to determine physico-chemical parameters, yeast levels, and the antifungal susceptibility of pathogenic yeasts in river water. Physico-chemical parameters and yeast levels were determined using standard procedures. Yeasts were identified by biochemical tests and 26S rRNA gene sequencing. Disc diffusion antifungal susceptibility tests were conducted on identified potential pathogenic yeasts. Physico-chemical parameters were within target water quality ranges (TWQR) for livestock farming but were mostly out of range for irrigation. Yeast levels (incubation at 37°C) ranged from 363 to 1 778 CFU/L. There were significant differences (p &lt; 0.05) in the physico-chemical parameters and yeast levels between some seasons and among the river systems under study. A positive association was observed between temperature, COD and yeast levels in all the river systems. Ascomycetes, which were the most prevalent isolates, were identified as Candida spp. (35%), Pichia spp. (13%), Cyberlinera spp. (12%), Meyerozyma spp. (11%), Clavispora spp. (10%), Saccharomyces spp. (6%), Kluyveromyces spp. (5%), Yamadazyma spp. (4%), Trichosporon spp. (3%), and Wickerhamomyces spp. (1%). Antifungal resistance of the potential pathogenic yeasts was as follows: flucytosine and miconazole (100%) &gt; fluconazole (78.5%) &gt; econazole, and miconazole and ketoconazole (49.6%) &gt; nystatin (15.2%). The river water systems explored in the study are used for agricultural, domestic and recreational purposes. Direct contact with the water, especially by immune-compromised people, may pose a health threat and should be further investigated.

Remoción de fosfato de ambientes acuáticos utilizando nanopartículas modificadas de Fe-Co/Quitosan

Chitosan modified iron-cobalt nanoparticles (CMNPs) were used for phosphate adsorption in synthetic wastewater and river water from the Jordan river in Tunja, Boyacá, Colombia. Phosphate adsorption by CMNPs reached 52.7% in synthetic wastewater and 58.7% in water taken from the Jordan river. This indicates that the CMNPs ability to adsorb phosphates is independent of other components within river water. Additionally, adsorption measurements were taken using the average pH, temperature, and phosphate concentration of the river water in order to ensure results comparable to those of (Kim 2017). A maximum adsorption rate of 0.138 mg of phosphate per gram of adsorbent was found with the majority of adsorption taking place within the first 15 minutes of contact with the adsorbent. The adsorption of phosphates using CMNPs presents an effective and environmentally friendly solution to reducing phosphates in aquatic ecosystems without altering the characteristics of river water.

Response mode of hydrochemical types of river water to altitude gradient in alpine regions.

The study investigates the hydrochemical type and characteristics of river water in permafrost regions in the Tibetan Plateau by analyzing 532 samples collected from the source region of the Yangtze River. The hydrochemical type of the river water was Cl--Na+-SO42-, and its hydrochemical characteristics were primarily influenced by the soil sources, though the influence of the sea sources and anthropogenic factors could not be ignored. Significant negative correlations were found between temperature and NO3-, SO42-, Mg2+, Ca2+, and between precipitation, relative humidity, and SO42- and Mg2+ in the river water. River water in the higher altitudes of over 5000 m above sea level was mainly recharged from glacier snowmelt water and by the supra-permafrost water and precipitation at the altitudes between 3500 and 5000 m above sea level. The controlled sources of hydrochemical characteristics of glacier snowmelt water were different for different ablation rates in the area with elevations of over 5000 m above sea level. Different hydrochemical types in different ablation rates implied the hydrochemical type was extremely sensitive to ablation periods in areas with elevation of over 5000 m above sea level. However, hydrochemical type was not sensitive to ablation periods from 3500 to 5000 m above sea level. The ionic concentration of glacier snowmelt water was mainly controlled by pollutants in glaciers and snow. Melting rates of glacier snowmelt water also had a certain effect on ionic concentration. Meanwhile, the stability of the hydrochemical type implied river water mainly controlled the hydrochemical type from 3500 to 5000 m above sea level. Hydrochemical type had no effect on elevation in end ablation.

Application of data from field-and labscale microbiological studies for treatment of phenolic leachate in natural systems

The phenol-rich leachate from semi-coke mounds formed as a by-product of oil-shaleprocessing is discharged via channels and rivers Kohtla and Purtse into the Baltic Sea withoutany treatment. The leachate from processed oil shale contains several organic and inorganiccompounds (oil fractions, sulphides, polycyclic aromatic hydrocarbons). The impact ofleachate on microbiological characteristics of river water and sediment as well as onabundance, activity and structure of biodegradative consortia have been studied. Themetabolic and genetic diversity of phenol-utilizing bacteria was characterized. Pollutionmarkedly altered all aspects of the studied microbial diversity. The structure and functioningof the bacterial communities changed significantly along the river and revealed remarkableadaptation to phenolic compounds in environment. The results demonstrate multiplicity ofcatabolic types of degradation of phenol and p-cresol and the existence of characteristicassemblages of species and specific genotypes among the strains isolated from the pollutedriver water.

The Regime of Water and Chemical Runoff in the Upper Volga Basin under Global Warming

The present-day conditions of the formation and distribution of the water resources and chemistry under global warming during the recent decades have been considered. The variations in the characteristics of river water and chemical runoff in the upper Volga basin have been estimated and analyzed. The regional features in the formation of river runoff and water quality variations in 1990–2015 have been determined. The environmental state of upper Volga basin areas has been indicated. The distribution of critical water pollution indices in the basin area has been analyzed, and that of the specific combinatorial water pollution index has been presented.

Simulation Modeling of the Combined Damage Caused by Cavitation and Abrasion in Sediment-Laden Liquids

Combined damage caused by cavitation and abrasion is a serious problem concerning hydraulic structures and machinery operating in hyper-concentrated sediment-laden rivers. Conceptualization of a model for simulation and assessment of the combined damage, therefore, becomes necessary. Experimental results demonstrate that sediments cast a strong influence on the combined damage caused by cavitation and abrasion. Sediments with size larger compared to a critical size tend to aggravate the combined damage, while sediments with size smaller compared to critical relieve the combined damage effect when compared against cavitation-only damage. Based on these results, a new model has been proposed and built in order to predict the combined damage and assess the range of sediments that relieve or aggravate the damage as sediments pass through the structure and machinery. The model represents an integral with damage as the integrand and sediments representing the domain of integration, and was built in three steps—the first step establishes a relationship between damage and sediments of a single size (SS model); the second step establishes a relationship between damage and sediments from an actual river (MS model); and the third step proposes a standard to assess the damaging effect on hydro machinery (CS model). Model parameters were verified using 74 cases of laboratory experiments. By comparing simulation results against experimental data, it has been inferred that the proposed model can be employed to study practical problems in a predictive manner and promote safe operation of reservoirs by predicting damage characteristics of river water.

Towards developing a river health index

A number of physical, chemical and biological water quality parameters are measured to understand quality conditions of a riverine environment. Various aggregation techniques have been used to reflect the combined effect of the existing or proposed quality levels. Water Quality Index (WQI) has been developed primarily for fresh water environments. Organic pollutants are not considered in many WQIs because analyses of organics are rather expensive. In general, fecal coliform and total coliform counts are measured to reflect biological contamination of water. With growing consensus on considering rivers as ecological entity, rather than merely a source of water for human consumptions, the emphasis is changing from water quality index (WQI) to River Health Index (RHI). As benthic macroinvertebrate species are differentially sensitive to many biotic and abiotic factors in river environment, macroinvertebrate community structure has commonly been used as indicator of stream water condition. A number of river health assessment methodologies have been proposed in past and several indices such as Ecological Health Index (EHI), Ecological Quality Index (EQI), Overall Index of Pollution (OIP) and River Pollution Index (RPI) have been developed using water quality variables and aquatic species for evaluating the ecological health of river systems. This paper attempts to review and summarize some of these indices with particular emphasis on measurable parameters included in such formulations. The analyses suggest that with sufficient scientific experience and understanding in this area, it is possible to define a River Health Index (RHI) by including algae, macroinvertebrates and fish species as measurable parameters along with routine physico-chemical characteristics of river water. One such formulation on RHI has been proposed by the authors in this paper. The novelty of the proposed formulation include simple calculations and presentation of RHI value on 0–100 scale. The biological indices used in ACEDP (2011) requires biological expertise which is not normally available with water resource managers. Hence species identification and counting based simple biotic indices have been proposed so that it can be easily done by non experts also. River Health Level (RHL) can be categorized as ‘critical’ or ‘excellent’ based on RHI value <=20 or >80. Thus RHI values can be used to identify the healthy or unhealthy stretches of the river. RHI can serve as scientific tool to assess the current status, need and effectiveness of any intervention required to improve the condition of the river. Application of this RHI formulation on main stream of river Ganga (India) is under study.