Risk Propagation in Spate Irrigation Systems: A Case Study from Sudan

Abstract

Farmers in flood-based irrigation systems face great uncertainties with respect to water supply. Using the Source-Pathways-Receptor and Consequence (SPRC) framework, this paper explores the sources of risks, propagation pathways, risk perceptions and consequences for the farmers, water users' associations (WUAs) and water managers in the Gash Agricultural Scheme in Sudan. The main source of risk is the extreme variability of rainfall, causing unpredictable flows regarding volume, timing and duration. The farmers, WUAs and system managers perceive the risks from floods differently. The farmers are primarily concerned by low floods, while the WUAs are more disturbed by untimely floods. The system managers are most troubled by high and potentially destructive floods. The poor state of the infrastructure, lack of proper maintenance and suboptimal operation aggravate the consequences of unpredictable flows. Consequently, the result is low and highly variable crop production. Besides paying attention to infrastructure improvement and regular operation and maintenance activities, more efforts in institutional arrangements and policy support could play an important role in coping with the risks indicated. The SPRC appeared to be a useful framework for analysing risks at different spatial scales and for different stakeholders in the spate irrigation system studied. RÉSUMÉLes agriculteurs dans les systèmes d'irrigation basés sur les inondations font face à de grandes incertitudes en ce qui concerne l'approvisionnement en eau. Utilisant la méthode Source-Voies-Récepteurs et Conséquences (SPRC), cet article explore les sources de risques, les voies de propagation, les perceptions des risques et les conséquences pour les agriculteurs, les associations d'usagers de l'eau (AUE) et les gestionnaires de l'eau du système agricole du Gash, au Soudan. La principale source de risque est l'extrême variabilité de la pluviométrie, qui entraîne des flux imprévisibles en termes de volume, de calendrier et de durée. Les agriculteurs, les AUE et les gestionnaires de système perçoivent différemment les risques liés aux inondations. Les agriculteurs sont principalement préoccupés par les faibles inondations, tandis que les AUE sont plus perturbées par les inondations intempestives. Les gestionnaires de systèmes sont les plus troublés par des inondations élevées et potentiellement destructrices. Le mauvais état des infrastructures, le manque d'entretien et le fonctionnement sous-optimal aggravent les conséquences des flux imprévisibles et entrainent une production agricole faible et très variable. Outre l'attention portée à l'amélioration des infrastructures et aux activités régulières d'exploitation et de maintenance, des efforts supplémentaires en matière d'arrangements institutionnels et de soutien aux politiques pourraient jouer un rôle important dans la gestion des risques. Le SPRC est apparu comme un cadre utile pour analyser les risques à différentes échelles spatiales et pour différentes parties prenantes dans le système d'irrigation p...

Flexibility as a strategy to cope with uncertain water supply in spate irrigation*

“…In an improved traditional system, with similar concerns of change and uncertainty, water managers adopt real actions for adjustability such as an emergency maintenance to the most critical structures and embankments and borrowing maintenance equipment from other collaborating agencies (cooperation) such as in the GAS (Fadul et al, 2018(Fadul et al, , 2019, and conjunctive use of groundwater as a supplementary source (redundancy). This option provided farmers in Wadi Zabid in Yemen with a substantial increase in irrigated area (van Steenbergen et al, 2010).…”

“…(2010) and Fadul et al . (2018). Major internal changes include a sudden breach in the river or canal embankment, escaped intakes, blockage of canals with sediment, failure of diversion weirs and changes in duration of the irrigation season (Mehari Haile, 2007).…”

“…External sources relate to changes in the system resulting from climatic factors and consequent effects, such as a sudden rise in the peak flood, an extended duration of high flood levels, an unpredicted low flood season, the occurrence of an early or late flood. Types of flood risks in spate irrigation are described in detail byvan Steenbergen et al (2010) andFadul et al (2018). Major internal changes include a sudden breach in the river or canal embankment, escaped intakes, blockage of canals with sediment, failure of diversion weirs and changes in duration of the irrigation season(Mehari Haile, 2007).…”

Floodwater harvesting to manage irrigation water and mesquite encroachment in a data‐sparse river basin: an eco‐hydrological approach

“…Sudan is among the African countries where spate‐irrigated agriculture is extensively practiced in river basins located within vast arid regions. There, seasonally and episodic heavy floods are exploited to irrigate adjacent agricultural lands (Fadul et al, 2019; Fadul, De Fraiture, & Masih, 2018; Fadul, Masih, De Fraiture, & Suryadi, 2020; Fujihara, Tanakamaru, Tada, Adam, & Elamin, 2020; Ghebreamlak et al, 2018). The system of irrigation in Toker Delta is the most complicated spate (flood) irrigation system in the world, as the amount of land irrigated depends on the available Baraka River flows (van Steenbergen, MacAnderson, & Haile, 2011).…”