Ecological integrity of a peri-urban river system, Chiraura River in Zimbabwe

Abstract

Ecological integrity of a peri-urban river system facing a plethora of anthropogenic pressures was assessed through multivariate analysis of physicochemical parameters correlated to the resident macroinvertebrate community. Monthly collection of macroinvertebrates and concurrent measurement of the physical and chemical parameters (dissolved oxygen concentration, percentage saturation of oxygen, pH, temperature, electrical conductivity and salinity) of water was done over a period of 5 months from November 2011- March 2012 in six sites across the Chiraura River. Macroinvertebrates were collected using the kick-net sampling technique, identified up to family level and enumerated at each site. Biodiversity indices were calculated for each site following the South African Scoring System version 5 (SASS5). A total of 1209 macroinvertebrates belonging to 49 families and11 orders were recorded in the Chiraura River. Most pollution sensitive taxa were found at sites 3 and 4 and the most pollution tolerant families were found at sites 1, 5 and 6. Sites4 and 5 of Chiraura River were the least polluted. Unsustainable anthropogenic activities, including industrial, domestic and urban agricultural activities affects water quality of Chiraura River. This is mainly through run-off and increased effluent to the river making routine water quality monitoring imperative.