Dynamics of allocations and deliveries in irrigation systems: investigating human-water interactions

Irrigation in Pakistan's Indus basin is a linked human-water system wherein surface supply from rivers is diverted through canal infrastructure and human planning and operations at federal, provincial, and canal command levels. Observing and understanding the interactions between these systems are of critical importance to the large agrarian economy of the country. In this work, we model the dynamics of canal entitlements and deliveries across four time scales of 10-daily, seasonal, annual and inter-annual intervals for 25 surface canals in the Punjab province of Pakistan using a data set spanning 11 years (2007-2017). The canal entitlements (set at the beginning of each growing season each year) are conceptualized as outputs of a 'human planning system' consisting of a group of organizations and decision-makers. Additionally, the surface irrigation deliveries are considered to be the result of a 'human operations system' comprised of a separate group of organizations and actors. We define metrics including canal supply consistency, consistency equity, and canal entitlement compliance to quantitatively characterize features of the planning and operations systems. Canal supply consistency is defined as the coefficient of variation of deliveries to entitlements ratio (to capture 10-daily intra-canal variability within a season in a canal). Consistency equity is defined as variability of canal supply consistency across all the canals. Canal entitlement complianceis the fraction at which the aggregate or total entitlement for a season for a canal is fulfilled and accounts for total deliveries in a season, but does not consider the timing of the deliveries. Using these (and other) metrics, we study interactions between entitlementsand deliveries across multiple time scales, and formulate and partially test (with the available data) a set of hypotheses to explain the observed outputs of the planning and operations systems. This study is a step in advancing understanding of the socio-hydrological system that underpins large-scale agriculture in Punjab, and can have applicability for studies in other regions. Furthermore, the metrics developed here provide complementary alternatives to traditional means for evaluating the effectiveness of irrigation water supply planning and operations.