GEOSPATIAL ASSESSMENT OF WATER QUALITY AND SUITABILITY FOR DRINKING

The observation of groundwater quality elements is essential for understanding the classification and distribution of drinking water, hence it is of importance to know the location of groundwater sources using ArcGIS. Blantyre, MISESA Ward Area, located in the southern part of Malawi. A large amount of the water requirement of MISESA is supplied from groundwater. The quality of this groundwater was determined by taking samples from 8 of the boreholes within the study area. The purposes of this investigation were (1) to undertake a geospatial assessment on groundwater quality and suitability for drinking (2) to provide an overview of present groundwater quality and (2) to determine spatial distribution of groundwater quality parameters such as, electrical conductivity, alkalinity, faecal coliform, total dissolved solids, total coliform concentrations, and (4) to map groundwater quality in the study area by using GIS and Geostatistics techniques and also to observe the groundwater potential of the area, all of this was done to analyse the suitability of drinking the water from underground. ArcGIS 10.7 and ArcGIS Geostatistical Analyst were used for generation of various thematic maps and ArcGIS Spatial Analyst to produce the final groundwater quality map. A drinking water quality index was then developed to describe the overall quality of groundwater in the study area. Very poor water quality was observed in MANJE area, and KAPENI area. Excellent water quality was observed in SOCHE area. There is a significant relationship between the land use in the area and the quality of groundwater.

The observation of groundwater quality elements is essential for understanding the classification and distribution of drinking water, hence it is of importance to know the location of groundwater sources using ArcGIS. The purposes of this investigation were (1) to undertake a geospatial assessment on groundwater quality and suitability for drinking (2) to provide an overview of present groundwater quality and (2) to determine spatial distribution of groundwater quality parameters such as, electrical conductivity, alkalinity, faecal coliform, total dissolved solids, total coliform concentrations, and (4) to map groundwater quality in the study area by using GIS and Geostatistics techniques and also to observe the groundwater potential of the area, all of this was done to analyse the suitability of drinking the water from underground. ArcGIS 10.7 and ArcGIS Geostatistical Analyst were used for generation of various thematic maps and ArcGIS Spatial Analyst to produce the final groundwater quality map. KEYWORDS: Groundwater Quality, Geographic information systems, Suitability for drinking and Groundwater Quality index.

Blantyre city was found In 1876, it is located in the southern part of Malawi with 15°47 ́10 ́S and 35°021 ́E, and it covers an area of about 240km2with an elevation of 1039m. Blantyre city has an estimation of 800264 population. The under groundwater quality of Blantyre city is complicated, as the groundwater levels in the basement aquifers are in most cases less than 15m below the surface. Surface fluctuations are typically 1-5m yield of 0.25-0.51 per second and this can usually be obtained from the basement rocks provided the saturated thickness of the weathered layer is more than 0m, usually capable for hand-pumped supplies (chiton, smith Cannington, 1984). The district experiences a tropical continental climate with two distinct seasons in the year. The rainy season is from November to April with a continuation in a form of light showers from the end of May to July. The mean annual rainfall is 1122mm of which 50% falls within 31⁄2 months between November and March with an annual temperature from 13° -21°. This understanding of the whole Blantyre city will determine the quality of groundwater the people in some parts of Blantyre to be specific MISESA area, are using

Traditional authority: Blantyre City

District: Blantyre