Water Quality Mapping of Ruvu River in Tanzania

Abstract

Increase in population and industrialization has strongly impacted the rivers and lakes all over the world. Meanwhile, Tanzania river’s water quality faces the same challenges. The Government of Tanzania is trying to overcome the problems by analyzing water quality data from its rivers. However, a lot of data collected require to be converted into a single value “index” understandable by decision and policy-makers. Therefore, the assessment by using different water quality indices like the National Sanitation Foundation for Water Quality Index (NSFWQI), River Pollution Index (RPI) and Overall Index of Pollution (OIP) are very useful. The present paper used water quality indices and land use maps to assess and investigates the water quality of the Ruvu river in Tanzania. Water quality samples collected from 14 sampling locations for the year 2014-2017 were used. The three water quality indices used in evaluation categorized the water quality of the Ruvu river as a medium, polluted and moderately polluted as per NSFWQI, OIP and RPI respectively. The index values were; 53.2, 4.69 and 4.78 for NSFWQI, OIP and RPI respectively. The impact of land use on water quality was analyzed by using Geographic Information Systems (GIS) and Remote Sensing (RS) techniques and ERDAS imagine. These assessment tools revealed that urban land use and agricultural land uses were the major sources of water pollution in this river.