Impact of Climate Change and Land Use Change Scenarios on Water Resources in Tha Chin River Basin: A Case Study of Suphan Buri Province, Thailand

Abstract

Water is one of the crucial resources for local livelihoods. Nowadays challenge of accessing to sufficient quantity and good quality for various activities: agriculture, ecosystem, domestic supply and recreation pose a major threat to security issue. Impact of climate change on water resources has been evidenced through intensification of changing hydrological cycle, which will entail more frequent and intense precipitation as well as longer dry spell periods. Although many stakeholders have increased awareness in climate change threat to water resources in the river basin, it is critical not to lose sight of the impacts of human activities on water resources. The effect of anthropogenic intervention is very difficult to separate from those of climate variations and need to be integrated into water resource assessment by means of holistic approach.

Climate change will have significant impact on agriculture in term of water availability for growing crop, crop productivity, and farming practice. Agricultural water management under climate change era is becoming increasingly complex and needs to consider socioeconomic change. This paper aims to assess impact of climate change on agricultural water for rice farming in Tha Chin river basin by raising Suphan Buri province as a case study. Climate projection in 2050 and 2070 reveals a slightly increase in temperature and precipitation. Suitability area for rice farming has been assessed by EcoCrop model by using the projected climate in 2050 as input. Two land use scenarios in 2050 will be projected by using business as usual (BAU) and green growth scenarios (GGC). Result reveals that GGC scenario tends to promote sufficient water supply. It is surprising that the largest area under rice cultivation nowadays is not suitable for rice farming in 2050. There is also increase in water demand due to rapid urban expansion, and it can possibly pose a threat to agricultural sector. Adjustment of agricultural plans and policies, building local capacity, and crop diversification are example of adaptation to build agricultural water resilience.