Upper Part of the Maha Oya Catchment Area Water Quality Distribution

Abstract

Water quality of the Maha Oya stream that runs across the Dolosbage, Rahala and Aranayakawas determined using water samples collected from twenty selected locations. Dug wells inthe catchment of the stream were also selected to to identify groundwater quality changes dueto water pollution in the river. These locations were selected from systematic sampling pointswere selected based on 800m grid a dug well was selected from the centre of the point oraround the centre point in each plot. Geographical Information System (GIS) packageArcGIS10 (Spatial Analysis Tool) was used to identify the spatial changes of water quality inthe river and surrounded groundwater pollution area. Water samples were assessed forselected parameter such as Temperature, pH and Electric Conductivity during the period of 5month in year 2013. In the all 20 river locations pH varies from 5.5 to 8. EC varies from17μs/cm to 70μs/cm. The counts of pH value were significantly lower in the populated areaand tea plantation areas than in other locations. A sociological survey was conductedconcurrently to study the impact of two communities (Tea state settlement and agricultural)living along the stream bank on water quality and social aspect. The results indicate that pHnear the populated area (Tea state settlement area) is probably due to the large amount ofhousehold waste that is discharged directly to the stream. The concluded that decompositionof organic matter produces CO2, which dissolves in water as carbonic acid, thereby loweringthe pH.