Tiki, Waktole; Gufu Oba, Peter & Tvedt, Terje (2013). An indigenous time-related framework for reconstructing the impact of disasters on ancient water systems in southern Ethiopia, 1560–1950 . Journal of Historical Geography.
This article uses an indigenous time-related framework to reconstruct the impact of disasters associated with floods, epidemics, droughts and famine on the ancient tula well systems in southern Ethiopia. We interviewed oral historians, who used the gada timeline to reconstruct the impact of disasters in the tula region from about 1560 to 1950. The Borana gada timeline is based on a system of social organization and transfer of power (each gada lasts for eight years) between five patri-classes called gogessa by the community. The Borana are able to recall events corresponding to a 40-year cycle (i.e. 5 × 8) when the same gogessa returns to power. With the return to power by each gogessa, grouped into seven naming clusters called maqabas, each gogessa experiences event-repetition or dhaaccii, which served as a repository of social memory. The time chronology in gada context and its social structure (gogessa), cyclical names (maqabas), and event-repetition (dhaaccii) are all connected in a complex historical narrative to reconstruct environmental events. To corroborate the oral history of the impact of disasters on tula wells, we used regional climatic information as proxy data. The findings showed that the gada timeline and its maqabas and event-repetition of dhaaccii correlated with the collapse of the wells, and with pastoral economy and human demographics. The gada timeline and its historical memory closely reflected climatic proxy data in terms of regional level disaster events.