• Mulugojam Wondyfraw,
• Prof. P.Suneetha
• Prof. T.V. Krishna

Lake Tana is the biggest freshwater body in Ethiopia that has enormous environmental, ecological, cultural, political and economical services. In its southern shore, one of the rapidly growing Ethiopian city Bahir Dar is situated. The expansion of the city leads to land use changes, which in turn have adverse effects on water quality and its ecosystems. Thus, the objective of the study was to investigate seasonal and spatial variability of Lake Tana water quality in the Bahir Dar gulf area by taking water samples in January 2017 and August 2017. The study identified factors that affect Lake Tana water quality using observation, questioner and key informant interviews. Then the collected data was analyzed using descriptive statistics, Wilcoxon Signed Ranks Test and Kruskal walis H-Test done using IBM SPSS statistics 20. The analytical result for mean value of water quality parameters have been observed as PH (7.75), water temperature(23.70C), dissolved oxygen(7.48mg/L), turbidity(14.35 FTU), electrical conductivity(160.14 µS/cm), total dissolved solid(76.14 mg/L), biological oxygen demand(0.41 mg/L), total hardness(97.28mg/l), nitrate(0.44mg/l), phosphate(0.3mg/l), sulphate(5.52 mg/l) while ammonia was not detected in both seasons. Furthermore, the statistical result have shown significant variation in season (P<0.05) for PH, turbidity, electrical conductivity, BOD5, total hardness and nitrate but the statistical result was not significant (P>0.05)for temperature, DO, TDS, Phosphate and sulphate while the test result depicted significant variation in site(P<0.05) for BOD5, temperature, electrical conductivity, nitrate, sulphate, total hardness, total dissolved solid, turbidity, PH, dissolved oxygen and statistically non-significant (P>0.05)for phosphate. The identified causes for Lake Tana water quality degradation was wastes, lack of government attention for the lake, invasion of weed, landfill, climate change, recession agriculture and lake water withdrawal for hydropower generation. Therefore, the city waste discharged in to the lake due to mounting urban infrastructure expansion, unmanageable urbanization, and associated service giving centers affected the water quality mainly through the impacted sites.

Lake Tana, water quality parameter, spatial and seasonal variation, urban infrastructure

"The Impact of Infrastructure Development on Lake Tana water Quality", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 2, page no.434-443, February-2019, Available :http://www.jetir.org/papers/JETIR1902563.pdf

"The Impact of Infrastructure Development on Lake Tana water Quality", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 2, page no. pp434-443, February-2019, Available at : http://www.jetir.org/papers/JETIR1902563.pdf