Modeling Adaptive Capacity in Co-Evolving Water and Agriculture Systems

Abstract:

Water and food security goals in agrarian economies are interlinked and increasingly challenging to fulfill due to growing populations and environmental uncertainties. System adaptability - the ability to reconfigure use of resources to effectively function under new conditions - is important for sustainably achieving such goals. However, there is limited understanding on how adaptability can be created, maintained, and measured. In this work, stylized models of adaptation are developed and applied on irrigation and agricultural production systems in the Punjab province in the Indus Basin of Pakistan. Irrigation in this largely arid region has undergone significant adaptation. The built infrastructure for surface delivery through water channels, spanning provincial to farm-scale, has changed to a conjunctive system in which ground water pumped from ~1 million wells augments water supplies. The transition occurred due to increasing uncertainty in surface water supplies, and enabled farmers to maintain and enhance productivity. Yields of key crops including wheat and sugarcane increased up to 72% during 1985-2010. Recent trends, however, show a need for stimulating new adaptations as system performance is stagnating and surface irrigation reliability has dropped below 40% in some cases. A systematic framework is used to model adaptation, in which human, technological, and environmental (HTE) components, interactions, and pathways are identified. A nested, controls system model is used to represent the hierarchical system of governance and operation at provincial, sub-provincial, and farm scale that sets and affects planned and actual irrigation water supplies and impacts productivity. A set of scenarios are developed in which new feedbacks (for adaptation) at daily and seasonal time scales are modeled and performance is simulated. The difference between the simulated (potential) and empirical performance is used to define a novel set of proxy metrics for quantifying adaptation potential and representing adaptation trajectories. The tools developed in this study showcase an application for coupled water and agriculture systems, and also advance research on adaptation from largely theoretical concepts to operational frameworks that can guide interventions for sustainability.