Exploring climate-adaptive drainage in water management: Enhancing soil moisture, crop resilience and groundwater recharge.

Drainage systems are essential for cultivated fields, ensuring optimal growth conditions for crops by preventing root zone wet stress. However, these conventional drainage systems also lead to a significant loss of water, a valuable resource that could be used to sustain crops during dry (summer) months. To address this, climate adaptive drainage or controlled drainage is employed, raising the water table “when possible given the ongoing agricultural activities”. This approach enhances aquifer recharge and stores excess water for use during the summer. Nevertheless, it remains unclear for farmers and water managers whether climate-adaptive drainage will improve agricultural performance and, if so, how to precisely manage water levels throughout the growing season to optimize performance. 

In this study, we conduct a synthetic experiment using the SWAP model to investigate the complex interaction between drainage types under different meteorological conditions, soil characteristics, and crop types. Our research aims to provide insights into the effect of climate-adaptive drainage for both farmers and water managers.

Our findings highlight that controlled drainage significantly enhances soil water content in sandy and loamy soils, contributing to climate resilience. However, its effectiveness in clay soils is small. It is important to note that climate-adaptive drainage has the potential to raise groundwater levels across all soil types, posing a potential risk of oxygen stress on crops. Regardless of soil type, the implementation of controlled drainage results in increased surface runoff and groundwater recharge, associated with a reduction in drainage flux. While the augmented surface runoff  poses potential issues such as soil erosion and water pollution, the positive aspect lies in the enhanced groundwater recharge, crucial for maintaining water availability and supporting ecological systems.