Analysis of the Quality of the Yatta Canal Water for Drinking and Irrigation Use

Water is essential for sustenance of life. In the world today more than 1.2 billion people lack access to clean drinking water. Water scarcity involves water stress, water shortage or deficits, and water crisis. While the concept of water stress is relatively new, it is the difficulty of obtaining sources of fresh water for use during a period of time and may result in further depletion and deterioration of available water resources. Water shortages may be caused by climate change, such as altered weather patterns including droughts or floods, increased pollution, and increased human demand and overuse of water. A water crisis is a situation where the available potable, unpolluted water within a region is less than that region's demand. Water scarcity is being driven by two converging phenomena: growing freshwater use and depletion of usable freshwater resources.

This project was aimed at investigating the quality of water from Yatta Canal, a water source for the Yatta district residents. This investigation was based on physical, chemical and microbial parameters. These parameters included acidity, alkalinity, hardness, electrical conductivity, total dissolved solids (TDS), total suspended solids (TSS), turbidity,pH, cations (Na+, K+ and  Ca+), anions (NO3-, NO2-, SO42- and PO43- ), metals ( Mg, Fe, Zn, Ni, Cu, Pb and Cd).

These parameters were tested in the laboratory using standard methods and their concentrations compared to the standard concentration recommended by bodies such as WHO, FAO and NEMA.

The water samples were collected from three distinct points in the canal. The first point, Kauthulini Bridge, is downstream ; the second point, Kahawani Bridge is within the middle of the canal length while the third point, Ngoliba Intake is upstream and the point where the canal starts, i.e, where it joins the its main source, the Thika River.

The data obtained for the three points was compared and ranges for various parameters was as follows; E. Coli (1-2), other coliforms (70-271), TDS (75.4 mg/L- 92 mg/L), TSS (398 mg/L-1318.6 mg/L), turbidity (29.6 NTU- 236 NTU), electrical conductivity (149.5 µS- 181 µS), pH (7.2-7.5), Na+ ions (100 mg/L- 120 mg/L), K+ ions (87 mg/L- 93 mg/L), alkalinity (80 mg/L- 92 mg/L eq. of CaCO3), acidity (13 mg/L-20 mg/L eq. of CaCO3), PO43- (0.09 mg/L-0.09 mg/L), SO42- (0.48 mg/L-1.24 mg/L), NO2- (0.03 mg/L-0.06 mg/L), NO3- (1.81 mg/L-2.13 mg/L), Fe (3.64 mg/L-44.06 mg/L), Mg (5.43 mg/L- 12.18 mg/L), Zn (0.11 mg/L-0.28 mg/L), Cu (0.00 mg/L- 0.02 mg/L), Cd (0.06 mg/L- 0.08 mg/L), Pd (N/D) and Ni (N/D).

Key words: Yatta Canal, Drinking and irrigation water quality, Biological contamination

Documentation :