An overview of water reallocation and the barriers to its implementation

Abstract

The growing number of areas facing water scarcity necessitates adaptive water management strategies beyond traditional water supply and demand management methods, which are becoming increasingly difficult in many regions. Water reallocation offers a flexible water management approach to mitigate water scarcity under changing socioeconomic, climatic, and environmental conditions. In spite of the numerous benefits of reallocating water between users, examples of successful water transfers are relatively sparse and the expected benefits are rarely met in full due to several complex impediments. This study overviews the current body of water reallocation literature, with a particular focus on the key barriers to wider implementation of water reallocation. We argue that to overcome these obstacles a more interdisciplinary approach to water reallocation should be advanced that couples developments in the natural sciences and engineering disciplines with current water reallocation scholarship, which is predominately rooted in the social sciences. Many examples of water transfers from around the world are used to illustrate both the benefits and challenges associated with reallocation, as well as to identify measures to overcome some of the major difficulties. We conclude by calling for an integrated research platform that focuses on supporting both voluntary and nonvoluntary forms of water reallocation; however, a greater emphasis should be on nonmarket means of water transfer since it is more feasible for many regions where water rights are not well defined and institutional capacity is insufficient.

Drought impacts to water footprints and virtual water transfers of the Central Valley of California

“…Growing global demand for tree nuts is primarily responsible for the rise in prices and is likely to have caused the shift to more water‐intensive tree nut crops. From an economic perspective, the reallocation of water to higher‐value uses is encouraged [ Zilberman et al ., ; Marston and Cai , ]—this is foundational to California's water market. However, from a drought management perspective, changing cropping patterns from easily fallowed field crops to tree and vine crops reduces flexibility in the water system.…”

Rural water for thirsty cities: a systematic review of water reallocation from rural to urban regions

“…a Dinar et al (1997), Hooper (2015. b Marston and Cai (2016). c Molle and Berkoff (2006 (case studies or comparative research rather than review or synthesis papers).…”

“…The geographic distribution of dyads documented by the literature may not fully represent actual reallocation patterns due to several potential biases (see Discussion), as well as the potential for water reallocation to occur through gradual and informal processes that are frequently undocumented due to the lack of infrastructure and formal decision-making (Venkatachalam and Balooni 2018). We also follow previously developed typologies by distinguishing between reallocation and transfers, where reallocation forms a subset of the broader category of transfers (Marston and Cai 2016); reallocation involves changes to existing or historic patterns of water use, while transfers involve the development of new supplies often considered 'excess flows' or undeveloped water in the donor region (Molle and Berkoff 2009). In addition to the 103 reallocation dyads included in our analysis, a further 28 dyads involved transfers of water that had not been historically allocated and used for human purposes in the donor region (described as 'excess flows' by Molle and Berkoff 2009, see SI 2(a)).…”

“…Water reallocation from rural to urban regions is driven by a set of factors associated with water supply, demand or, often, the combination of the two (Marston and Cai 2016). We expect that reallocation will be driven by increases in urban water demand associated with population growth in regions with limited, unreliable or polluted supply options.…”

Managing Water Scarcity at a River Basin Scale with Economic Instruments

“…It is into this context that economic instruments have thus assumed a greater role for global water (re)allocation objectives. However, Marston and Cai (2016) correctly observe that water reallocation is challenging because of a general global lack of suitable and effective institutional capacity. They suggest requisite investments needed to support complex reallocation mechanisms, such as markets or water pricing, may render them inaccessible to many contexts -driving the need for research into non-market reallocation institutional support mechanisms in the future.…”