THE APPLICATION OF SUB INDEX AGGREGATION METHOD TO ASSESS THE HEALTH OF A WATER BODY

The environmental health of inland water bodies can be described using water qualityparameters that describe the physical, chemical and biological status of the water. Each ofthese parameters reflect different characteristics of the water body and can be assessed bycomparing with threshold values detaikd in water quality guidelines such as the FreshWater and Marine Water Quality Guidelines. Assessing the status of a water body using asuite of water quality parameters is cumbersome and fraught with difficulty, as for a givenlocation some parameters may fall under Ihreshold values whilst others exceed guidelinevalues. To simplify and unify the interpretation based on individual water qualityparameters, these can be combined into a single dimensionless number by considering eachmeasured water quality concentration and its corresponding guideline value. This singlenumber is called the 'water quality index' (WQI) and is used to assess the overall status ofthe water body quantitatively and objectively.Many methods have been derived over the years to determine the WQI for differentapplications. These methods are &roupedinto two categories; 'sub-index' and 'statistical'.As to-date, no guidelines have been specified on the selection of a methodology. However,it has been acknowledged that the method used to derive the WQI should retain valuableinformation from each parameter and retain its contribution to determining the overallhealth during the combining process.This paper reviews methods available to determine WQls for a range of applications. Thepaper will describe the application of the SIA method to a set of water quality data alongthe Yarra River in Victoria, Australia. The results were useful in identifying the trend inWQvariation. The Sub Indices Aggregation (SIA) method could be used by Authorities forrapid assessment of water bodies to identify their suitability for different purposes based onthe quality of water. Application of the method can also assist with locating critical areasthat could urgently require rehabilitation

Application of Moringa oleifera seeds and Musa cavendish as coagulants for lead, nickel and cadmium removal from drinking water

Contamination of drinking water sources by heavy metals in many South Asian countries has become a major public health concern. As conventional chemical treatment of the contaminated water may not be feasible for many remote communities in the region due to technical and financial constraints, some low-cost, native and abundantly available natural materials have emerged as a potential alternative to the expensive water treatment chemicals. Plant-based materials 'Moringa oleifera' (MO) and 'Musa cavendish' (MC) were investigated in this study as the coagulants for removing lead (Pb), nickel (Ni) and cadmium (Cd) from groundwater containing metal ions at their typical concentrations found in selected South Asian countries. Coagulation tests were conducted with the individual coagulants and their combinations on synthetic and real groundwater samples. The best removal efficiencies for Ni (77%) and Cd (67%) were achieved by the combined coagulants dosed in a mixing manner at the optimum coagulant dosages of 200+200 mg/L from the initial concentration of 31 mug/L and 5 mug/L, respectively. This was attributed to the presence of additional binding sites with different active functional groups, leading to higher removal efficiency compared to the individual coagulant. However, MO alone showed the best removal for Pb (87%) at the coagulant dose of 300 mg/L from the initial concentration of 19 mg/L; suggesting that MO had a good affinity towards Pb. The study demonstrated that MO and MC have the potential to remove Pb, Ni and Cd from drinking water to meet the World Health Organisation (WHO) drinking water standards

Effects of Solution Matrix on Moringa oleifera Seeds and Banana Peel in Eliminating Heavy Metals, Fluoride and Turbidity from Synthetic groundwater samples

Plant-based biomass has become an environmental-friendly water purification agent in replacing conventional chemicals. In the previous study, Moringa oleifera (MO) seeds and banana peel (BP) have been selected based on their moderate to high effectiveness in removing lead, cadmium, nickel, arsenic, turbidity, and fluoride from synthetic groundwater samples. This study was aimed to investigate further the effects of solution matrix on the biomass effectiveness. Batch experiments were conducted by using coagulation technique and the initial pH of the solutions was controlled to be at pH 7. The results demonstrate that the removal rates for most of the pollutants in multi-contaminant solution were higher compared to the single-contaminant solution. The reason could be due to electrostatic or mutual interactions between contaminants present in the solution thus improved the removal rates of those contaminants. The findings are significantly important to understand the effects and removal behavior of the biomass in different solution matrix

A methodology for estimating yield from small ungauged rural catchments

© 1991 Dr. Lekamge Niranjali Nelunika JayasuriyaAn estimate of streamflow yield from ungauged catchments is often required by water management Authorities. A survey of Authorities indicated that the techniques used in computing streamflow yield from small ungauged rural catchments were limited to a range of empirical methods with questionable accuracy. There is clearly a need to develop a more reliable simplified methodology. The proposed methodology is based on the calibration of a rainfall-runoff model using a number of gauged catchments and the development of regression relationships between catchment physiographical characteristics and model parameters. The parameters are then used in conjunction with the rainfall-runoff model and meteorological observations to estimate streamflow yield from ungauged catchments. The 2-parameter rainfall-runoff model (MOSAZ) was developed only after a detailed study of actual evapotranspiration and parameter optimisation. Morton's model, based on Bouchet's complementary theory, proved to be an adequate method to calculate actual evapotranspiration from catchments. The model was tested with data from forested, native pasture and irrigated wheat catchments. The model is considered to be superior to methods based on pan evaporation as the actual evapotranspiration predicted using Morton's model is independent of the catchment cover and the prevailing soil moisture conditions in the catchment. A number of optimisation techniques based on direct search and gradient methods were tested for accuracy. From the methods tested, the pattern search and the Gauss-Marquardt algorithms proved to be superior. The interaction between satisfactory compliance with simple least squares error assumptions and the goodness-of-fit between observed and predicted streamflow was also studied. An important feature of the proposed methodology is the use of a multi-dimensional plotting routine termed Andrews' curves to separate the 184 catchments in the study region into a number of hydrologically homogeneous groups based on catchment physiographical characteristics which are related to MOSAZ model parameters. Regression relationships between MOSAZ model parameters and catchment physiographical characteristics were developed for one homogeneous group of catchments based on information from 17 catchments. The developed regression relationships were used to calculate streamflow from four test catchments to demonstrate the applicability of the developed methodology. As the results appeared promising, it is possible to extend the developed methodology to other homogeneous catchment groups

A GIS based water end use demand modelling

The 'end use' of water is a breakdown of the total household water usage such as water used for toilets, showers, washing machines, taps, lawn watering, etc. The Victorian Government, in Australia set a 15% per capita consumption reduction target by 2010 based on the Water Resources Strategy that has been developed for Melbourne. Therefore, there is a need to measure and model residential end uses of water to ensure the effectiveness of conservation efforts and to determine whether the set target reduction is achieved. This paper describes GIS-based modelling of end uses of water from a number of single-family homes in Greater Melbourne, Australia. The study involves the analysis of water demand data at 1-minute and 5-second intervals from logged households collected by Yarra Valley Water in Melbourne, Australia in 2001 and 2004. The result of this study improves understanding on the end uses of water and provides information to assist where to focus water conservation efforts that would yield the most effective result financially, environmentally and acceptable to everyone

Temperature and rainfall thresholds for base use urban water demand modelling

This paper shows how a new daily demand model incorporating base use values calculated using temperature and rainfall thresholds for East Doncaster, Victoria, Australia was evaluated. The model is based on a postulate that total water use is made up of base use and seasonal use, where base use represents mainly indoor use and is independent of climatic effects such as rainfall and temperature and seasonal use on seasonal, climatic and persistence components. Using the daily data collected for East Doncaster, Victoria, Australia water supply distribution zone and the corresponding rainfall and temperature data from 1990 to 2000 reference or threshold levels in which water use is independent of temperature and rainfall were identified. The base values were correlated with the day of the week and climatic factors such as temperature and rainfall. Results revealed these base values to be climate independent but are affected by weekends and weekdays. The calculated base use values using temperature and rainfall thresholds were incorporated in a total water demand model and showed strong correlation with R2 of 71%. The model is further validated using an independent set of data from 2000 to 2001 and yielded an R2 of 83%

Identification of homogeneous areas for drought frequency analysis

Owing to high spatial and temporal rainfall variability, rationale water management decision-making is complex. Hence, it is essential to identify homogeneous areas to assist water management. This paper focusses on separating the study area into homogeneous groups to predict the risk of occurrence of a drought event. The severityduration-frequency (SDF) curves were developed to determine the relationship between the probability of a drought occurring with a certain severity and frequency at the selected stations in Victoria, Australia. Two techniques namely cluster analysis and modified Andrews curve were used in grouping study area that have similar climate characteristics with respect to risk of occurrence of drought (i.e. rainfall variability). Based on the results, mean seasonal precipitations (i.e. summer and spring) were found to be the most important parameters in clustering droughts. The study area was divided into six clusters and they adequately covered the study area. A mean drought frequency curve was developed for each homogeneous group to determine the probability of vulnerability to a drought event with a certain severity. The advantage of separating stations into homogenous groups based on similar drought characteristics is that it eliminates the necessity to carry out a detailed drought characteristic analysis for any location of interest

Estimating residential end uses of water

Abstract not available

Understanding residential water use

Abstract not available

Assessing the health of water sources using water quality indices

Not available