Abstract:
Batena River is an important river in and around Hossana City. The river's water quality has
deteriorated due to waste disposal, dumping of solid waste, soil erosion, urban runoff, and
agricultural activities that load pollution into the river. However, the people nearby use the river
widely without adequate and reliable information about water quality and pollution status. The
aim of this study is to evaluate the water quality status of the river and to analyze its suitability
for drinking and irrigation purposes. Six sampling stations were selected and sampling was done
twice in each of the wet and dry seasons. Various physicochemical and bacteriological
parameters, namely, pH, Turbidity, TDS, EC, TH, DO, BOD, Ca2+, Mg2+, Na+
, K+
, Cl-
, CO3
-2
,
HCO3
-
, SO4
2-
, PO4
3-
, NO3
-
and Fecal coliform were determined for all samples following
standard procedures. The findings of the analysis were compared with maximum acceptable
limit values recommended by WHO and ESA for drinking and FAO for irrigation. The water
quality for drinking purpose was evaluated using the Weighted Arithmetic Water Quality Index
(WAWQI) method. WQI values ranged from 195.1 to 283.9 in the rainy season and 56.1 to 126.1
in the dry season. The computed WQI values Indicates that at all sampling sites classified as
under ‘unsuitable’ category for drinking purposes in the case of wet season. In the dry season, it
varied from poor to unsuitable Category. River water quality for irrigation were evaluated by
using irrigation water quality indices, including SAR, RBC, PI, %Na, SSP, KI and MR values,
revealed that all river water samples were suitable for irrigation use except magnesium ratio
during wet season at sample point BR4. From the analyses, it is understood that Turbidity (95 ±
21.2 to126.5 ± 35 NTU), PO4
-3
(0.33 ± 0.016 to 0.46 ± 0.05mg/L), BOD5 (6.2 ± 0.8 to 11.5 ±
0.8mg/L) and Fecal coliform (31 ± 4 to98 ± 9 CFU/100ml) during the wet season and Turbidity
(9.2 0 ± 2.96 to16.2 ± 1.59NTU), PO4
-
3 (0.249 ± 0.02mg/L), BOD5 (6.28 ± 0.34 and 7.08 ±
1.49) and Fecal coliform (12 ± 1 to 52 ± 6 CFU/100ml) during dry season are above the
recommended limits that have a significant impact on the river water quality for drinking
purpose. This could have been related to the municipal waste, dumping of solid waste, soil and
rock erosion, urban runoff, and agricultural activities that load pollution into the river. Finally,
the study recommends sustainable management to prevent pollution in Batena River.
