The effect of seasonal variations in physical parameters on quality of gravity flow water was investigated in Kyanamira Sub-County, Kabale District, Uganda. The seasonal variations in the physical parameters (pH, temperature, electrical conductivity (EC), turbidity, colour, total dissolved solids (TDS), and total suspended solids (TSS)) were determined during wet and dry seasons. Composite samples from gravity flow water sources were collected monthly from March to August, 2014 and then analyzed. Temperature was measured using thermometer; pH, EC and TDS were determined using a multimeter, turbidity, colour and total suspended solids were determined by spectrophotometric method. TDS, pH and temperature were the most contributing parameters to water quality variations in both seasons. The mean pH values varied between 3.78-4.84 from March to August, 2014 at all study sites. These pH values were consistently below the WHO permissible range of 6.5-8.5. Similarly, total suspended solids varied between 0.66-2.17 mg•L −1 and were well above the recommended WHO limit of zero mg•L −1 at all study sites. Turbidity mean values varied between 0.83-3.7 NTU and were outside the recommended limits of 3 NTU at Kigata (3.7 NTU) only. Temperatures (20.3˚C-21.15˚C) for all the study sites were within the recommended limit of 20˚C-30˚C in water for domestic purposes. The mean values of physical parameters for the wet season were: temperature (21.12˚C), colour (12.5 PtCoU), turbidity (3.4 NTU), TDS (76.76 mg•L −1), TSS (2.13 mg•L −1), pH (4.19) and EC (152.7 µS•cm −1) were different from those of the dry season (temperature (20.99˚C), colour (0.93 PtCoU), turbidity (0.53 NTU), TDS (77.33 mg•L −1), TSS (0.67 mg•L −1), pH (4.86) and EC (158.65 µS•cm −1). Basing on these findings above, it was evident to justify discouraging the use of gravity flow water at these study sites for domestic purposes without proper treatment.

The study was designed to investigate temporal and spatial seasonal variations in quality properties of gravity flow water samples collected from Kigata, Kacuro, Kihanga, Kitibya and Kanjobe located in Kyanamira Sub-County, Kabale District, Uganda. Physical, chemical and biological parameters such as pH, temperature, dissolved oxygen, total dissolved solids, electrical conductivity, turbidity, colour and total suspended solids, total hardness, total alkalinity, chloride, fluoride, nitrates-N, nitrites-N, ammonium-N, sulphates, total phosphate, sodium, calcium, magnesium and some heavy metals were analyzed. Total iron, lead, chromium, copper, zinc, manganese and cadmium were analyzed by atomic absorption spectrometry. Two of the basic biological parameters for drinking water such as faecal coliforms and salmonella were analyzed by incubation followed by counting colony forming units (CFUs). Statistical presentations of data including cluster analysis, dendrograms and principal component analysis were used with the assistance of PAST software. Temperature, pH, TDS dissolved oxygen, cations, anions (chemical parameters) and salmonella, faecal coliforms were the major contributing parameters to gravity flow water's quality variations during both seasons. Values of pH ranged between 3.78 and 4.84 from March to August in all study sites and they were consistently below the WHO permissible pH range of 6.5 -8.5. Total suspended solids ranged between 0.66 and 2.17 mg·L −1 and were above the recommended WHO limit of zero value in all study sites. Salmonella and faecal coliforms colonies were present in scaring numbers in the wet season. In March, salmonella counts at Kacuro (14 CFU) and Kanjobe (128 CFU) while faecal coliforms counts at Kacuro (515 CFU) and Kanjobe (228 CFU). The findings of this study call for special attention when using gravity flow water.How to cite this paper: Ngabirano, H.,