The Impact of Urbanisation on Water Quality of Some Water Catchments in Buea and Its Environs

Abstract

Water bodies provide valuable ecosystem services, such as water supply, production, recreation and aesthetics. Having water available in sufficient quantity and quality contributes to the maintenance of health, and this depends on water catchment characteristics among other factors.  This work assessed   the impacts of urbanization on some water catchments in Buea and its environs. A survey was done on five catchments; Bunduma water catchment, Bwiteva water catchment, Sandpit water catchment, Wovilla water catchment and, Kombo and Mile 16 water catchments; during which all the land uses around the catchments were noted. Semi-structured questionnaires were administered to the inhabitants around each of the five water catchments, to know more about the anthropogenic influences and the views of the inhabitants on how the water catchments had changed overtime. Water samples were collected in three sets, from inlets and outlets of each catchment, for physico-chemical, bacteriological and phytoplankton analysis following standard procedure. Although respondents had varied views with respect to the water quality from these catchments, 55% were not satisfied and were of the opinion that the quality has dropped over the years. The respondents reported that people suffer mainly from the following water borne diseases: typhoid (50%), skin irritation (30%) and diarrhea (20%). They noted that water from these catchments was used for drinking, irrigation and laundry (65%). The physico-chemical parameters assessed were all within the WHO (2017) acceptable limits for drinking water except for lead and cadmium concerntrations that were higher than the 0.01mg/L and 0.003 mg/L respectively for these two heavy metals. Coliform, Shigella and Salmonella were observed only in outlets. Coliform had the highest load (702±277 CFU/100ml) while salmonella had the lowest (0.8±0.37 CFU/100ml) and the differences across the catchments were statistically significant (P=0.01). There were variations in the occurrences and abundances of phytoplankton across sites. For all the inlets, a total of 23 species were identified from 20 genera, 17 families and 6 divisions. Ankistrodesmus gracilis (22.9%), Cyclotella meneghiniana (17%) and Closterium abruptum (15.5%) had the highest species abundance while Craticula sp and Trachelomonas sp (0.1%) had the lowest species abundance. Bacillariophyta was the most abundant division (35%) while Euglenophyta had the least (3%). In the outlets, a total of 30 species were identified from 23 genera, 19 families and 6 divisions. Ceratum sp (12.53%), Closterium arcuarium (11.23%) and Nitzschia closterium (8.12%) had the highest species abundance while Peridinium umbonatum and Phacus curvicauda had the lowest (0.06%) species abundance. Bacillariophyta recorded the highest species abundance (60.8%) while Cyanophyta had the least (0.6%). These deteriorating conditions of the different catchments are a consequence of uncontrolled farming, building and construction as well as poor waste disposal around and along the water catchments. There is great health risk and necessitates management actions that will safeguard these water catchments both in quality and quantity as well as avoid an epidemic in the near future.

Keywords: Impact, Urbanization, Water quality, Water catchment, Buea, Phytoplankton, Bacteria

DOI: 10.7176/JEES/13-9-04

Publication date: November 30^th 2023