Water value flows upstream

Arjen Hoekstra postulated in 2001 that the value of water accumulates in an upstream direction: water value flows upstream. The ultimate source of this value is the rain. This original idea he used to develop the water value-flow concept. This article shows that the water value-flow concept has much to offer in terms of contemporary challenges. It is fully consistent with the "Five Bellagio Principles on Valuing Water" that the High Level Panel of Water published in 2017, and can make significant contributions to the first four principles. This article also shows that the concept can make many more contributions, including incorporating precipitationsheds, and thus include the source areas of rainfall in valuing water. Yet, until now, this innovative and potentially ground breaking concept has been largely ignored by researchers and practitioners in the fields of water resources management and economics. We conclude that the value-flow concept is a unique and promising framework for the integrated assessment of the value of water within a water resources system or river basin. We suggest that the concept can be enriched by incorporating instream benefits, water quality, as well as social, cultural, and spiritual values. We also suggest to test whether the concept can be usefully applied, and add value, to the emerging fields of socio-hydrology and water accounting.