Runoff irrigation practices and challenges in western lowlands of Eritrea

Introduction. The arid and semi-desert lowland agro-ecological zones of Eritrea experience lowprecipitation, much lower than the requirements forrobust agricultural production unless supplemented by properly functioning runoff irrigation systems. However, an in-depth understandingof the principles and practices of runoff irrigation, identification of itspotentials and challengesand come up with viable solutions is necessary. Materials and methods. Qualitative and quantitative, descriptive and analytical research methodologies are applied. Primary and secondary data are used to identify existing constraints. Besides, global and regional databases are extensively utilized to fill information gaps. Results. The total potential cultivable land of Eritrea amounts to 2.1 million ha, out of which 71.4 % is rainfed and 28.6 % is irrigation. But, the potential irrigable land as reported by FAO is much lower (187,500 ha), out of which 50,000 ha is within the Western Lowlands. Considering such disparities and the less likely scenario of lowest irrigation potential, the actual equipped for spate irrigation at national level would amount to only 33.6 %, meaning there are still a lot of possibilities for expansion. The causes of malfunctioning of the existing systems are associated to structural, operation and maintenance, and management. Lack of historical hydrological data is among the highly likely reasons, which in turn greatly affects hydrological simulations. Conclusions. Despitecommendable efforts made to expand the improved runoff irrigation in the Western Lowlands, most of the projectshavefailed to achieve the intended purposes. Thus, comprehensive and simple mathematical modelsfor ma­king hydrological predictions have been suggested