For the past 30 years, the increases in population pressure and external influences, such as economic
growth, have accelerated the demand for land within the Upper Manyame River catchment in Zimbabwe
which has caused substantial changes in landuse. The general objective of this research was to assess the
impacts of landuse activities on the water quality of the Upper Manyame River which drains the rural and
urbanised part of the catchment up to flow gauging station C21. Landcover data for the month of April in
years of 1984, 1995, 2003 and 2011 were acquired from available Landsat TM and ETM images and were
classified through the maximum likelihood digital image classification using the supervised classification
approach. The status of water quality of the Upper Manyame River was also assessed through analyses of
historical concentrations and pollution loads for TP, DO, COD, NH3-N, SS, Pb, NO3, BOD5, EC, PO4-P and TN
at the Environmental Management Agency (EMA) gauging station CR21 sampling point for 1996, 2000/1
and 2008/9. Water quality of 15 monitoring sites comprising 25 water quality parameters were monitored
monthly from January to June 2012. These locations were selected to reflect a wide array of landuse
for both the dry and wet seasons. The results indicated that there was an increase in pollution load from
1995 to 2012; for TP from 130 kg/day to 376 kg/d, and for TN from 290 kg/day to 494 kg/d. This indicates
high pollution levels which have severe impacts on downstream users and also severe sewage contamination.
Significant deviations occurred in DO (0.1–6.8) mg/L, COD (11–569) mg/L, BOD5 (5–341) mg/L,
PO4-P (0.01–4.45) mg/L, NH3-N (0.001–6.800) mg/L and EC (38–642) lS/cm. Hydrologic Response Unit
and buffer analysis were used to determine the dominant landuse which contributes to a certain water
quality. Results of digital image classification indicate that woodland/forest, grassland and bareland
decreased between years 1984 to 2011 by 24.0%, 22.6% and 31.7% respectively. This was mainly due to
expansion or increase of agriculture and urban areas by 24.4% and 41.6% respectively over the same time
period. It was concluded that settlements and agricultural areas are the ones mainly affecting the water
quality in Upper Manyame River with a Pearson’s Correlation Coefficient of r = 0.97 for COD and r = 0.78
for TSS respectively. It was also observed that the water quality status of the Upper Manyame River and
its tributaries is very poor and the level of pollution generally increases from upstream to downstream.
The results obtained provided baseline information which may be used in the development of appropriate
water quality management systems in the catchment. Thus the study recommended a combined
programme of point source control and landuse modification.