Understanding Resilience of Private Water Supply Water Quality to Meteorological Drought in Scotland

This thesis investigates the impact of meteorological droughts on water security in Private Water Supplies (PWS) across Scotland, focusing on the challenges posed by spatial and temporal variability in the meteorological drought patterns. The present study contributed to ongoing efforts to develop targeted strategies to safeguard and future-proof water resources and public health Scotland and eventually meet the SDG 6.1. Using the Standardised Precipitation-Evapotranspiration Index (SPEI) at a refined 1 km2 resolution, this research enhances the understanding of historical drought patterns in Scotland and their effects on PWS water quality. The findings showed that historical meteorological droughts in Scotland were highly variable in space and over time, revealing significant regional differences, with the South and Southeast experiencing prolonged meteorological droughts between 1981 and 2010, while the East showing increasing drought severity and intensity from 2001 onwards. Though limited by a subset of 36 sites, a far future analysis (2041-2080) analysis using the UKCP18 data highlights the growing water deficits posed by meteorological drought under changing climatic conditions. The projections across 36 sites in Scotland indicate a shift toward drier conditions by 2061-2078, with increasing meteorological drought severity, frequency, and intensity, particularly in the West and South, while the East also becomes drier. Meteorological drought duration is projected to decrease, but drought frequency is expected to rise by 2 drought events in the far future period. The analysis also highlighted no direct impact of meteorological drought on water quality of PWS, however this may be due available data limitations, based on inconsistent monitoring, missing water source classification, and variable local authority (LAs) engagement. A statistical analysis of water quality data, showed that source type played a critical role in determining water quality. Through an analysis of LAs perceptions and experiences, the study revealed deficiencies in current drought management practices, emphasising the need for adaptive, long-term strategies to create a more resilient PWS water management system. Overall, this research contributes to understanding the intersection of meteorological drought, water quality, and public health, emphasising the need for adaptive management strategies to safeguard water security in Scotland's PWS under changing climatic conditions.