Modernization of spate irrigated agriculture: A new approach

Abstract

Spate irrigation, a floodwater harvesting and management system, has for the past 70 centuries provided a livelihood for about 13 million resource-poor people in some 20 countries. Despite being the oldest, the system still remains the least studied and the least understood. It is only in the past two decades that the system has been subject to some modernization interventions, much of which focused on improving floodwater diversion efficiency. Effective floodwater diversion measures are necessary, but they must be supplemented with equally effective field water management and soil moisture conservation measures if sustainable improvement of land and water productivity is to be achieved. This paper draws on studies conducted in the past 5 years, particularly in the Republic of Yemen, Pakistan and Eritrea. The studies employed both qualitative and quantitative methods and assessed the modernization package that could result in lasting enhancement of crop productivity in spate irrigated agriculture. The suggested modernization measures include: avoid overstretching the command area; limit the number of irrigation turns to two or an irrigation gift of 1000 mm; avoid field bund heights of more than 1 m; adopt a field-to-field water distribution system instead of an individual field water distribution system; opt for water rights and rules that entitle downstream fields to the more frequent small and medium floods thereby ensuring equity in both water quality and quantity; optimize soil water-holding capacity and infiltration rate through pre-and-post irrigation tillage, combined tillage as well as soil mulching.

Status and Potential of Spate Irrigation in Ethiopia

“…The costs of permanent headwork for large systems including diversion weirs, breaching bunds and siphons as estimated from one of the ongoing project (Koloba Spate Project) ranges from USD 330 to 450 per hectare (Alemehayu 2008). These costs are very reasonable and at par with 'sensible' investments in spate irrigation elsewhere (Mehari et al 2010). …”

Assessment of Suitable Areas for Home Gardens for Irrigation Potential, Water Availability, and Water-Lifting Technologies

“…Crop water requirements for the dominant crop ranges from 5.2 mm/day to 8.1 mm/day [14]. In general, spate irrigation has been traditionally used in Ethiopia [15]. The integration of home gardens with irrigation would help to increase productivity in the region by enabling year-round cropping (i.e., both rainfed and irrigated system).…”

Optimizing Flood and Sediment Management of Spate Irrigation in Aba’ala Plains

“…In the Aba'ala Plain, both traditional and modern spate irrigation systems are practiced. Managing floodwater, occasionally large in volume and often destructive and having high sediment load, is the major challenge to make spate irrigation sustainable and productive (Mehari et al 2011).…”