Reservoir Operation in View of Effective Utilization of Limited Water in Semi‐Arid Areas The Case of Gumsalasa Earthen Dam Irrigation Scheme in Tigray, Ethiopia

Tigray is one of the semi-arid and drought-prone regions of Ethiopia. The rainfed agriculture is characterized by low productivity and the region faces an average annual cereal food deficit of 180 000 t. Realizing these problems, the regional government has been engaged in earthen dam irrigation development activities since 1995. So far 44 earthen dams with related irrigation facilities have been constructed. The Gumsalasa earthen dam was constructed in 1995 with a reservoir capacity of 1.9 million m3, which irrigates about 67 ha. In Tigray the main irrigation season starts in January, which is four months after the end of the main rainy season. The reservoir is therefore exposed to evaporation during these four months. This demands formulation and implementation of an operational plan that can reduce losses and increase the benefits. In this regard, a change in reservoir operation from the present (January–June) to the proposed (September–January) has shown the possibility of increasing the irrigated area and the number of farmers. This indicates the potential of the proposed change to contribute towards regional food security if it is practised at existing and future earthen dam irrigation schemes in Tigray. Copyright © 2016 John Wiley & Sons, Ltd.