Yeshitela, Kumelachew (Ph.D.)Solomon, Terusaw2019-08-022023-11-082019-08-022023-11-082019-07http://etd.aau.edu.et/handle/123456789/18723A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Masters of Science in Landscape ArchitectureCities in the developing countries are facing enormous challenges in the provision of employment opportunities and basic services such as drinking water, sanitation and proper wastewater disposal for the rapidly increasing urban population. They are characterized by relatively high demand for food and clean water and generation of large volume of urban wastes, being discharged into natural water bodies, contaminating rivers, lakes and other freshwater bodies used for urban agriculture. Addis Ababa, being one of the fast-growing cities in Africa is not an exception to this situation. Significant segment of human population and land resource are involved in urban agriculture with the use of urban rivers which are proven to be highly polluted with its high health risk. The general objective of this thesis was to identify the type and the extent of pollutants of agricultural concern in the water used for irrigation at Mekanisa-Gofa–Lafto Cooperative Farm, aimed at selecting an appropriate ecological water treatment elements for contextualized landscape design that can reduce the pollution level of the water for irrigation. Water samples were taken and analyzed for 9 parameters including BOD, COD, pH, EC, TSS, Na, TH, and Cl& Zn). As part of selecting an appropriate ecological water treatment elements,field test was also carried out to study the potential of floating treatment wetland in reducing the pollutants in the study site. The irrigation water were treated with floating treatment wetland with Vetiver grass for total of 7 days. The results showed that the floating treatment wetland was able to reduce the BOD (73.68%), COD (73.92%), pH (0.39%), Cl- (43.12 %), TH (66.56%) and TSS (96.21%) values, approaching the recommended irrigation water quality guideline values within 3 days. On the contrary, there was an increase in EC (22.2%) and Na (15.2%) concentration the values of which exceeded the recommended values, attributed to evapotranspiration or the introduction of the surrounding soil into the irrigation water of Mekanisa-Gofa-Lafto Co-operative farm.enConstructed wetlandGrass swaleLandscapePollutantsIrrigation waterWater treatmentThesis