Examining spatial variations in the utility of SPI as a 1 to 3 month-ahead streamflow indicator

West, Harry; Quinn, Nevil; Horswell, Michael

Abstract

Droughts are a common meteorological phenomenon and a significant natural hazard. Despite this we lack a common understanding of the definition of a drought event and a detailed understanding of drought onset and termination. In its simplest form however a drought can be defined as a deficit of rainfall relative to normal conditions. This rainfall deficit will eventually propagate through the hydrological system into terrestrial water storage and streamflow. Using the latest available hydro-meteorological datasets from the UK Droughts & Water Scarcity Programme, this paper aims to examine the relationship between rainfall deficit (quantified by the standardised precipitation index for a range of accumulation periods ranging from 1 to 12 months) and environmental drought (quantified by the standardised streamflow index) in 293 catchments across Great Britain. Through this we identify the rainfall deficit accumulation periods that are associated with the more severe environmental droughts, and in doing so identify the role of local catchment characteristics (quantified by the base flow index) in moderating drought frequency and severity. By developing a spatial understanding of the relationship between rainfall deficit accumulation and environmental drought, we identify and map the variation in critical SPI accumulation thresholds for estimating environmental drought risk over the forthcoming 1 to 3 months. The intention is that this will provide water resource managers with a simple tool to aid effective decision making in drought event management.

• Presentation Conference Type: Poster
• Conference Name: UK Drought & Water Scarcity Conference: Addressing Current & Future Challenges
• Start Date: Mar 20, 2019
• End Date: Mar 21, 2019
• Acceptance Date: Jan 16, 2019
• Publication Date: Mar 21, 2019
• Publicly Available Date: Jun 6, 2019
• Peer Reviewed: Peer Reviewed
• Public URL: https://uwe-repository.worktribe.com/output/850336
• Additional Information: Title of Conference or Conference Proceedings : UK Drought & Water Scarcity Conference: Addressing Current & Future Challenges