Rethinking the “Duty of Water” Concept in Socio-Hydrology

This paper explores normative dimensions of sociohydrology through an analysis of the duty of water concept in water management. It shows that while this concept had antecedents in early-19th century research on steam engine efficiencies in Britain (in part for mine dewatering purposes), it acquired more complex sociohydrologic applications in canal irrigation systems of colonial India. These systems spread water over large areas of land, much larger than antecedent wells and inundation canals in the region (e.g., at a duty of 216 acres/cfs). Extensive water systems have served a dynamic mix of territorial, revenue, and food security aims, the normative dimensions of which were discussed in irrigation and famine reports. Their mixed impacts on social welfare and environmental health (e.g., malaria habitat) were also debated. Application of the duty of water concept to spread water as far as possible for diverse social purposes thus had normative dimensions that a sociohydrology model can help assess. Decades later in the U.S., by comparison, duty of water measurements were adapted to define minimum standards of irrigation (e.g., duties of 50-70 acres/cfs; or maximum depths in acre-feet/acre). These measurements helped quantify beneficial use requirements in western water law, which are the normative basis and limits of water rights appropriation. In both regions, determining the duty of water has been a matter of jointly scientific and practical debate as to what constitutes norms of water use in different landscapes. Although analytically the duty of water concept has been largely eclipsed by other measures of water use, it may now have broader potential for articulating integrative norms of community and environmental water management at least in part through the field of sociohydrology.