Physical parameters of tropical wetlands in Lake Victoria basin: a case study of kigwal/kimondi, nyando and nzoia wetlands

Abstract

This study entailed the assessment of physical parameters of selected tropical wetlands within Lake Victoria Basin. The research study measured rainfall, flow rate, turbidity, and pH of Kigwal/Kimondi, Nyando and Nzoia wetland ecosystems found within eastern side of Lake Victoria Basin by use of Vernier Calliper Instrument. The study found out that approximately 78 to 89% of recharge water was retained with the highest calculated water budget being for Nzoia wetland (26.24(0.99) × 106 m3) during rainy season with Kigwal/Kimondi (8.85 (2.91) × 106 m3) and Nyando (11.47 (0.75) × 106 m3). There was a seasonal variation of flow rate, pH, and turbidity with rain season indicating high levels of turbidity, flow rate and variable pH levels in the wetland ecosystems as compared to dry seasons. A statistically significant correlation existed between the measured parameters with coefficient of correlation ranging from r=0.8976 to 0.9987 with p < 0.05). Turbidity values of the three wetlands at the inlets during rainy season were above the recommended values by EPA but decreased considerably at the exit of the wetlands to within the recommended NTUs by EPA of 1 to 5 NTUs. There was a highly correlated relationship between rainfall amounts, flow rate and turbidity.pH values ranged from slightly acidic (6.79(± 0.55)) at the inlets) to basic nature (8.44(± 0.17)) especially at the outlets of the wetland ecosystems. Intervention programs should be initiated to ensure that physical properties of wetlands are secured.