Rethinking Irrigation Efficiency: Chain Irrigation in Northwestern Spain

Abstract

In recent decades, approaches to evaluating irrigation efficiency have undergone a radical reevaluation. Classical models considered drainage water "lost" to irrigation by flowing out of the system. The recognition that drainage water can remain in the system and become available for use by downstream irrigators has forced the reassessment. Irrigation may be relatively inefficient at the irrigation system and field levels but quite efficient at the basin level. The implications for small-scale, gravity-flow canal systems managed by farmers, which constitute 85% of the world's irrigated area, are significant. These implications are explored in an historic and ethnographic analysis of the chain irrigation system of the Orbigo valley of northwestern Spain. This system of drainage and reuse helps to account for high and sustained agricultural productivity by farmers in the region over several centuries. The property rights institutions devised by farmers to manage this system are discussed and its internal organization compared with south Asian cascade irrigation.

Prospects for Improving Gravity-Fed Surface Irrigation Systems in Mediterranean European Contexts

“…To establish whether an irrigation technique is efficient for a specific territory, it is necessary to quantify the water availability and the irrigation water demand for that area and then to evaluate the efficiency of the irrigation systems. However, the irrigation efficiency should be evaluated using a larger-scale approach (from the irrigation district to the basin), considering not only the hydraulic efficiency but also the secondary benefits [90]. Such secondary benefits range from recreational features, including the picturesque rural roads bordering the canals, to ecological functions, including the preservation of the traditional fauna and flora of the rural landscape.…”

The landscape technology of spate irrigation amid development changes: Assembling the links to resources, livelihoods, and agrobiodiversity-food in the Bolivian Andes

“…While resilience ecology-related fields examine irrigation cooperation and conflict (Guillet, 2006;Lansing and Miller, 2005;Mitchell and Guillet, 1994;Ostrom and Gardner, 1993), the focus is expanded via political ecology to the conditions of spate irrigation related to socially conditioned and often contested access rights (formal and informal) and power relations, governance, and development institutions including the state (Birkenholtz, 2009;Boelens, 2008;Gelles, 2000;Paulson, 2005;Trawick, 2001Trawick, , 2003. 3 Political ecology, and similar views (such as hydrosocial relations; Linton, 2008), also put a particular emphasis on irrigation related to modern development, which includes ideas and policies of the spatially ''fixing water'' (Linton, 2010), the modernizing of waterworks making them more ''legible'' (Scott, 1998), and producing geographic configurations of water-scarcity landscapes conjoined to those of relative surplus (Zimmerer, 2011) as well as development institutions amid globalization (Bebbington, 2001;Bebbington and Batterbury, 2001;Stadel, 1997) and neoliberalism (Perreault, 2005(Perreault, , 2008Zimmerer, 2009).…”

Performing drip irrigation by the farmer managed Seguia Khrichfa irrigation system, Morocco

“…The reviewed studies using some definition of IWUE for calculating efficiencies all assume that water drained is lost, but (unless it goes to sinks) this is water that can potentially be re-used elsewhere. It may for instance be recaptured for use by the same farmer or system, which in a closed river basin (Molle et al, 2010;Seckler, 1996) will lead to a reduction of downstream water flows and thus implies a de facto re-allocation of available water (see also Molden 1997;Molden and Sakthivadivel, 1999;Seckler et al, 2003;Guillet, 2006;Lankford, 2006;Perry 2007;van Halsema and Vincent, 2012). This example not just shows that calculations about 'savings' and 'losses' are always scale-sensitive, but also that they are of little practical use without further specification of who incur these gains and losses.…”

“…van Halsema and Vincent, 2012, p.11). Indeed, switching scales can drastically change one's assessment of water efficiency from poor to good when water initially regarded as 'wasted' is beneficially re-used (Clark and Aniq, 1993;Guillet, 2006) …”

“…Actual water savings depend on where the 'saved' water is going: is it productively used elsewhere or does it flow to the sea? Indeed, and as many scholars have noted, when water saved at plot or system level is recaptured for use within the same plot or system, this may result in reducing downstream water flows, thus causing a re-allocation of water rather than a net saving (Molden, 1997;Seckler et al, 2003;Guillet, 2006;Lankford, 2006;Perry, 2007;van Halsema and Vincent, 2012). Because of this scale-and context sensitivity of water efficiency measures, they are not comparable across locations (van Halsema and Vincent, 2012).…”