A coupled agent-based and hydrological modelling approach using value-belief-norm theory to simulate anthropogenic impacts on water resources

From the paper

Abstract

This study presents a novel socio-hydrological modelling approach to examine anthropogenic impacts by simulating human water use behaviour within a coupled human-hydrological system. It integrates an agent-based model (ABM), grounded in the Value-Belief-Norm (VBN) theory, with the distributed SWAT-MODFLOW model to capture agents’ decision-making processes. The VBN framework and behavioural rules in ABM are informed by field surveys of farmers in the Mahabad River Basin. The ABM-SWAT-MODFLOW model is validated against observed data using Nash-Sutcliffe efficiency (NS) and the coefficient of determination (R2) for runoff, along with Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) for groundwater levels. Calibration results (NS = 0.61, R2 = 0.69, MAE = 1.16, RMSE = 1.92) and validation results (NS = 0.52, R2 = 0.60, MAE = 1.65, RMSE = 2.00) indicate satisfactory performance. The study further explores the effects of improved financial conditions on the hydrological regime through three scenarios. Findings reveal that higher incomes increase farmers’ preference for low-water-consuming crops, leading to a rise in Mahabad River discharge into Urmia Lake by 26.22 %, 27.08 %, and 42.77 % across the scenarios. Concurrently, the average groundwater drawdown in the Mahabad aquifer decreases from 0.66 m to 0.55, 0.51, and 0.17 m, respectively. These results underscore the significant influence of farmers’ economic conditions on socio-hydrological interactions, offering valuable insights for water resource management.