above sea level (m a.s.l) in the north and west; a central plateau region between 100 to 250 m a.s.l.; with the south and the east of the region situated within the English Lowlands (~50 m a.s.l.). Considerable spatial variation in rainfall exists across the region, ranging from over 1800 mm in the Welsh uplands to ~650 mm in the southeast of the region (Met Office, 2014). Several large towns and cities are within the supply area including Birmingham, Nottingham, Leicester and Stafford (Figure 1). Severn Trent Water supplies approximately 7.4 million people with potable water provision sourced from reservoirs, river abstractions and groundwater, each contributing approximately one third of total supply. The water supply region is divided into 15 water resource zones (Severn Trent Water, 2014a). These zones are defined by the regulating bodies as largest possible zone in which customers share the same risk of a “the resource This study explores the implications of using long climate shortfall” (OFWAT, 2004). data in water resources assessments for just one of these zones: the North Staffordshire Water Resource Zone. Supplying water for a population of approximately 523,000 people, water provision in this resource zone is sourced from both groundwater and an impounding reservoir (Tittesworth Reservoir) on the headwaters of the River Churnet. The Severn Trent Water drought plan (Severn Trent Water, 2014b) identifies that within this water resource zone the 1933-1935 drought had the greatest impact on simulated reservoir storage over the baseline modelling period (1920-2010). Rainfall Five long-term daily precipitation series (Figure 1) are available for the study area (British Atmospheric Data Centre, 2014). The rainfall series extend back into the nineteenth century, but vary in length accordingly: Wall Grange (A; 1882-2012), Chatsworth Gardens (B; Nanpantan Reservoir (C; 1887-2012), Rugby (D; 1872-2012) and Rhayader (E; (Figure 1). Site E lies outside of the water supply region, however, it is located near the Elan Valley reservoir system that supplies water into the study region These sites are selected
above sea level (m a.s.l) in the north and west; a central plateau region between 100 to 250 m a.s.l.; with the south and the east of the region situated within the English Lowlands (~50 m a.s.l.). Considerable spatial variation in rainfall exists across the region, ranging from over 1800 mm in the Welsh uplands to ~650 mm in the southeast of the region (Met Office, 2014). Several large towns and cities are within the supply area including Birmingham, Nottingham, Leicester and Stafford (Figure 1). Severn Trent Water supplies approximately 7.4 million people with potable water provision sourced from reservoirs, river abstractions and groundwater, each contributing approximately one third of total supply. The water supply region is divided into 15 water resource zones (Severn Trent Water, 2014a). These zones are defined by the regulating bodies as “the largest possible zone in which customers share the same risk of a resource shortfall” (OFWAT, 2004). This study explores the implications of using long climate data in water resources assessments for just one of these zones: the North Staffordshire Water Resource Zone. Supplying water for a population of approximately 523,000 people, water provision in this resource zone is sourced from both groundwater and an impounding reservoir (Tittesworth Reservoir) on the headwaters of the River Churnet. The Severn Trent Water drought plan (Severn Trent Water, 2014b) identifies that within this water resource zone the 1933-1935 drought had the greatest impact on simulated reservoir storage over the baseline modelling period (1920-2010). Rainfall Five long-term daily precipitation series (Figure 1) are available for the study area (British Atmospheric Data Centre, 2014). The rainfall series extend back into the nineteenth century, but vary in length accordingly: Wall Grange (A; 1882-2012), Chatsworth Gardens (B; Nanpantan Reservoir (C; 1887-2012), Rugby (D; 1872-2012) and Rhayader (E; (Figure 1). Site E lies outside of the water supply region, however, it is located near the Elan Valley reservoir system that supplies water into the study region These sites are selected