Soil and Water Assessment Tool (SWAT) is a river basin scale model developed to quantify the impact of land management practices in large, complex watersheds and river basins. Hydrologic models are vital for the analysis of climatic change repercussions and water resources balance thereby permitting the evaluation of water resources and facilitate their management while valuing different choice consequences. A good knowledge of the problem and the analysis of various solutions require an integrated approach to the geographical information which can offer a global vision of the various components of the system. Geographic Information System (GIS) as an essential tool to collect, stock and search data required for simulations and are characterized by relatively simple operations manipulating various data. Contrarily, hydrological models are characterized by complex operations including iterations on a more reduced number of data. Thus, GIS permits to group all disposed watershed data into structured database system. The first article, “Application of SWAT Hydrological Model to Upper Bernam River Basin (UBRB), Malaysia”, by Sai Hin Lai and Fitri Arniza describes the use of remote sensing, GIS, and a distributed hydrologic and water quality model (SWAT) for assessing the rainfall-runoff and sedimentation load in multiple watersheds. In this study, necessary data sets representing land uses, hydrology, weather, soils, elevation, and surface characteristics were integrated in a GIS tabular, vector and grid formats.

The degree of anisotropy and asymmetry depends on several factors: efficiency of the weathered horizon, bedding anisotropy, and bedding dip angle. In the second article, “The Mineral Effects of Sedimentary Layers on Groundwater in Choba, Rivers State, Nigeria”, C N Nwankwo and M U Igboekwe have carried out a study aimed at determining how the dissolved aquiferous sedimentary rock minerals from different sedimentary layers affect the quality of the analyzed water samples. Groundwater samples of different sites of Choba, Rivers State, Nigeria, were analyzed for quality checkup and the physicochemical parameters obtained were matched with international standards. Suitable pretreatment measures have been suggested to improve the quality of potable water. The study further reveals that there is absence of saltwater intrusion into the study area.

Land filling is one of the most common methods for disposal and has been suggested to be the most economical and environmentally tolerable methods around the world. Leachate produced from landfills is known to be a high strength organic wastewater which is difficult to treat with conventional treatment methods such as biological methods due to their high fraction of molecular weight, refractory organics compounds. In a study, “Effects of Ultrasonic Irradiation on Concentration of Chemical Oxygen Demand in Landfill Leachate ”, by Chua Sze Ye, Puziah Abdul Latif, Shaharin Ibrahim and Nurliza Rosli, landfill leachate was selected as the testing matrix and the effects of operating conditions such as ultrasonic power density, varying pH, dilution factor and addition of various amount of FeSO4 on COD reduction were investigated. The study reveals that the removal of COD in landfill leachate was mainly contributed by higher concentration of hydroxyl radical which leads to higher reduction of organic matters.

Environmental noise is a worldwide problem. However, the way the problem is dealt with differs immensely from country to country and very much dependent on the culture, economy and politics. After air and water pollution, noise in urban areas is considered to be the third most serious kind of pollution by the World Health Organization. Ordinarily noise pollution in urban areas is being generated through different sources such as road traffics, construction and commercial activities, industries, airports and residential regions. The fourth article, “Evaluation of the Environmental Noise Level of Sangamner City, and the Study of Sound Absorption Coefficient of Wood of Select Trees to Control Noise Level”, by Madhav V Jadhav, deals with the study of environmental noise pollution of the city of Sangamner, Dist-Ahmadnager (M.S.), India, and measurement of absorption coefficient of wood of some selected tree species which are useful to minimize the noise pollution by plantation along side the roads, as well as to produce a green belt around factory, government offices, schools and colleges, etc.

Water is one of the most valuable natural resources on earth. An infinitesimal proportion (0.007%) of all water on earth is readily available fresh water. In this water, the concentration of toxic chemicals and biologically available nutrients in excess can lead to diverse problems such as toxic algal blooms, loss of oxygen, destruction of fish, loss of biodiversity and loss of aquatic plant beds and coral reefs. Major proportion of drinking water is drawn from the groundwater. The rate of depletion of groundwater levels and deterioration of groundwater quality is of great concern. In the fifth article, “Suitability Evaluation of Groundwater for Drinking Purpose: A Case Study of Barnala, Punjab, India”, Venu and Madhuri S Rishi have conducted a study in the area by random sampling analysis methods. The result of the chemical analysis reveals that the groundwater of the study area is brackish and values of major ions, in comparison with the permissible limits for drinking water (as by BIS) are not suitable for drinking purposes either due to salinity or fluoride. Various water quality problems like high sodicity and high salinity were also reveled. Suitable pre-treatment measures have been suggested to improve the quality of groundwater prior to consumption.

Mango (Mangifera indica L.) is one of the best commercial crops of India, accounting for> 54% of the total mango produced worldwide. Over 30 different varieties of mango are grown, the most important one is Alphonso, which is rated best in the world. A good number of plant mites are injurious horticultural crops causing considerable yield loss. In the last article, “Biochemical Changes of Some Important Organic, Mineral and Inorganic Compounds in the Leaves of Mango (Mangifera indica) due to the Infestation of Oligonychus mangiferus (Rahman and Sapra)”, by Sanjib Ghoshal, Snehasis Barman and Manjubikash Saha, a study was undertaken to assess the changes in the biochemical components of mango leaves due to mite infestation. The study reveals that a significant depletion of important organic, mineral and inorganic compounds occurred due the infestation of Oligonychus mangiferus in the leaves of Mango.

It was found that amount of chlorophyll, total protein, total carbohydrate, Mg, Zn, Cu, Fe, nitrate and nitrite were reduced by a significant proportion whereas the amount of phenol was increased by mite feeding.

-- G S Brahma
Consulting Editor