Adaptation strategies for rainfed rice water management under climate change in Songkhram River Basin, Thailand

Abstract

This study investigates the potential impacts of climate change on water resources and evaluates adaptation strategies on rainfed rice water management under climate change scenarios in the Songkhram River Basin, Thailand. The Soil and Water Assessment Tool (SWAT) model was used to project the future water availability under climate change scenarios for the period of 2020–2044. Future annual water availability is expected to remain unchanged due to unchanged future rainfall but expected to reduce from June to November due to changes in seasonal rainfall. The effects of supplying irrigation water to reduce the impact of climate change and increase rainfed rice production were evaluated. To increase the rice production by 15%, it is proposed to construct a reservoir with a capacity of below 65 MCM in each of the 15 sub-basins to fulfill the irrigation water requirements during the rainfed rice season. Alternatively, adaptation at the farm scale can be implemented by constructing ponds with a capacity of 900 m3 to store water for 1 ha of rice field to meet the potential rice yield during the non-rainfed rice season. The results of this study are helpful to policymakers in understanding the potential impacts of climate change and the formulation of adaptation strategies for water and rice sectors in the basin. HIGHLIGHTS Adaptation strategies for rainfed rice water management under climate change scenarios were evaluated at the farm and basin scale.; The Soil and Water Assessment Tool model was used to forecast the future water availability for the rainfed cultivation.; A pond with a capacity of 900 m3 is recommended to store water for 1 ha of rice to produce the potential rice yield.;

Keywords

• adaptation
• irrigation water requirement
• swat model
• water availability