Climate-driven water stress and hydrological drought vulnerability in the dry zone basins in Sri Lanka: insights from climate modelling and Random Forest algorithm

Autor: Wijekoon, Tharindi, Rajapakse, Lalith, Matheswaran, Karthikeyan
Zdroj: Modeling Earth Systems and Environment; 20240101, Issue: Preprints p1-18, 18p
Abstrakt: Drought, a consequence of prolonged precipitation deficiencies, is a significant hazard exacerbated by climate change. Highly susceptible to extreme climatic events, Sri Lanka faces drought as its most prominent hazard, necessitating comprehensive assessments. This study focuses on the escalating impact of hydrological drought intensified by climate change on the Maduru Oya and Kirindi Oya dry zone basins in Sri Lanka, crucial due to their vulnerability to altered hydroclimatic dynamics. Monitoring hydrological droughts in these regions is paramount for ensuring a reliable water supply for irrigation and other purposes. The research utilizes the Streamflow Drought Index for the monitoring of hydrological droughts. It considers six CMIP6 (Sixth Phase of the Coupled Model Intercomparison Project) Global Climate Models, with the CNRM-HR-1 model chosen as the preferred model. Two future Shared Socio-economic Pathway scenarios, SSP1-2.6 and SSP5-8.5, were selected to project future climatic conditions. The Random Forest algorithm was utilized to predict future streamflow in the two selected sub-basins. The hydrological drought assessment reveals the heightened vulnerability of the Padiyathalawa sub-basin in the Maduru Oya basin, with a notable rise in moderate hydrological drought occurrences under both future scenarios. Conversely, the Wellawaya sub-basin in the Kirindi Oya basin exhibits susceptibility to frequent moderate hydrological droughts, along with an 80% increase in severe drought occurrences under the SSP5-8.5. Consequently, both basins are projected to face water scarcity in the future. This underscores the importance of implementing measures to ensure a reliable water supply, given the substantial impact of climate change on watershed hydrology.
Databáze: Supplemental Index