Quantifying the hydrologic response of land use/land cover change (LULCC)
is of paramount importance to improve land management. This study was carried
out to analyze the effect of LULCC on water quality and quantity. LULCC of the
watershed in 1986, 1999 and 2011 was analyzed from Landsat satellite images
using supervised classification. Time series and
point data were collected from the upper and
lower sections of Wedesa, Wesha and Hallo Rivers. Water quality parameters (turbidity, suspended solid
(SS), total dissolved solid (TDS), pH, electric conductivity (EC), total
organic carbon (TOC), ammonia, nitrate and phosphate) were analyzed in the
laboratory. A considerable decline in forest and an increase in woodland were
observed in the watershed during the indicated periods. Turbidity, SS, TDS and
EC were significantly higher (P <
0.05) in the lower section of the rivers compared to the upper ones. Ammonia,
nitrate and phosphate were higher in the lower section of some rivers compared
to the upper ones. In general, water quality in the upper watershed of the
three rivers was better than the lower one with respect to considered parameters,
which might be related to the observed LULCC. Most water quality parameters
varied (P < 0.05) seasonally in
both the upper and lower sections of the rivers. Despite the irregular rainfall
pattern and increased water consumption from the catchment, the annual
discharge of the Tikur-Wuha River to Lake Hawassa shows an increasing trend. We
concluded that the discharge is not only related to the upstream LULCC but also
to the management of the Cheleleka wetland. However, further investigation is
required to determine the dominant factors affecting inflow discharge to Lake
Cite this paper
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