Assessing the impacts of land use changes on river Enyau water quality :

Abstract

This study aimed at assessing the impact of l land use changes on River Enyau sub catchment area and using land-uses of 2000 and 2016, computing the land use change analysis using Microsoft excel and comparing the relative impact of this land-use change on water quality into the River Enyau. Arc GIS 15.2 was used to identify and characterize the land-use. It should be noted water resources in Uganda are under immense pressure due to various human activities such as agriculture, sand mining and other activities which are disastrous and with adverse environmental impacts. this study, generally was looking at pollution of river Enyau in Arua city, found in the north west part of Uganda. Potential pollutants were characterized, Water Quality Index (WQI) for each sample point was calculated and engineering measures were developed to help in pollution reduction or elimination on the river. The water quality of the river was sampled in different areas and samples were collected from the spots were people fetch water for agriculture and domestic purposes. Grab samples were collected from River Enyau, during the period of October 2021 and January 2022. A total of 8 samples were collected and analyzed in terms of 10 physio-chemical water quality indicators, namely turbidity (T), Electrical conductivity (EC), dissolved oxygen (DO), pH, total dissolved solids, water hardness (WH), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total phosphorous and Temperature according to Standard methods. Turbidity ranged from 53.92- 62.43 NTU, COD ranged from 14.75 -15mg/l, PH ranged from 8.055 - 8.1225, EC ranged from 103.75 - 120.25 μs/cm, Total phosphorus ranged from 1.5 -1.6 mg/l, Water Hardness ranged from 63.25 - 68.5 mg/l, Temperature ranged from 26.5 – 26.7 OC, DO ranged from 4.7 4.67- 4.64 mg/l, BOD ranged from 8-9mg/l, TDS ranged from 54.75 - 62.25 mg/l The results were compared with the WHO standards for surface water quality and almost of them were found to be high. Based on the average concentrations of both physical and chemical parameters of all the four (4) sampling points of River Enyau, it was concluded that the river is highly polluted due to the high concentrations of the various pollutants and discharge from the different human activities such as fertilizer application, hospital discharge and other kind of pollutants from the surrounding areas of the river