Adaptation Methods in Water Resources Management for Improving Irrigation Reliability Under Climate Change

Abstract:

The impact of climate change is increasingly being investigated for adaptation in management to improve the resilience of human and environmental systems under uncertainty. Improvement of water provisioning for agricultural producers is of utmost importance because they are continually challenged by the increasing frequency of droughts projected in future climates. In this study, we developed a system dynamics (SD) model for aggregated water system management to evaluate the effectiveness of adaptation methods in improving irrigation reliability under projected climate change scenarios (RCP 4.5 and RCP 8.5). Four adaptation methods, including greenhouses (GHs), crop planting time shifts (PTS), irrigation technology (IT), and managed aquifer recharge (MAR), were evaluated for either reducing irrigation water demand or for increasing irrigation water supply. Climate change projections (2020 – 2090) were analyzed by two methods. First, we assumed that each decade after 2020 may happen in the next ten years. Second, we used the entire climate projection period to analyze adaptation methods with consideration of innovation adoption behavior according to word of mouth, advertisement, drought stimuli, and effectiveness of the method starting in 2020. We found a strong increase in demand of land resources and financial capital to adopt adaptation methods in order to fully alleviate water scarcity due to future droughts. The MAR adoption ratio increases the fastest where 75% of total potential adopters would implement MAR by 2060 as a cost-effective and easy-to-adopt method, whereas GHs and IT increased by 30%. When future climate includes alternative wet and dry years (RCP 4.5), MAR would be more effective in mitigating drought impacts. GHs and IT would perform better in reducing water demand especially when multi-year droughts occur (RCP 8.5). Economic water productivity increases 15 times by the 2080s with expanded GHs producing high value crops. Combinations of diverse adaptation methods based on the available resources and climate scenarios can result in more sustainable irrigation supply and economic benefit, compared to individual methods. This work brings insights for stakeholders on discovering implementation scales of various methods to improve water resource management under future climate.