Abstract:
Excess household wastes from settlements, agrochemical and industrial
effluentsfromthe watershed into Lake Ziway can pause a great problem in Lake Ziway.
This study was therefore conducted to analysis the amount dynamics, and influences
the external and internal household wastes, agrochemical and industrial loads, on Lake
Ziway ecosystem. Water samples were collected on a monthly basis from nine sampling
sites of the lake for the analysis of some selected water quality parameters in 2014 and
2015 in different seasons. The physicochemical parameters were measured in-situ with
portable multimeter and nutrients were according to the APHA [1]. The inflows from
Katar and Meki Rivers indicate the main external nutrient sources of the lake
ecosystem. The study showed a general trend of higher external nutrient load in the
wet than in the dry seasons. These high nutrient loads indicate the susceptibility of
Lake Ziway toapproach Eutrophication levels. Person Correlation indicated that
precipitation, water level, discharge flow and air temperature had weak to strong
positive correlations with SRP, TP, TIN and TN,while DO, pH, EC, total alkalinity
(TA) and soluble reactive silica (SiO2-Si) were negatively correlated with water level
and discharge outflows. In order to minimize more pollution of the lake water quality
and to eventually restore the lake, management of fertilizers and pesticide usage in the
lake watershed should be given urgent priority
