UK Drought Management and Monitoring

Transcription

1 UK Drought Management and Monitoring WMO/ISDR Expert Group Meeting on Hydrological Drought Indices Geneva 1-2 September 2011 Ann Calver (WMO Commission for Hydrology Advisory Group Member leading on Water, Climate & Risk Management ) 1

2 Drought in the UK drought orders issued in England rainfall June-Aug 1976 as % of mean Source: UK Climate Change Adaptation Sub-Ccmmittee, 2011; Rodda & Marsh, 2011 uses of abstracted water 2

3 River flow indicators Source: Environment Agency 3

4 Projecting river flow indicators RIVER THAMES AT KINGSTON (NATURAL) Forecasts of mean monthly river flow from July 2006 for 12 months for different % average rainfall % of Average Rainfall Flow (Ml/d) Oct-04 Jan-05 Apr-05 Jul-05 Oct-05 Jan-06 Apr-06 Jul-06 Oct-06 Jan-07 Apr % 100% 80% 60% Excep High Note High Above norm Norm Below norm Note low Excep low Actual Source: Environment Agency 4

5 Groundwater level indicators Source: Environment Agency 5

6 Reservoir stock indicators Source: Environment Agency 6

7 Soil water indicators Source: Environment Agency 7

8 Drought management plans EU Environmental Regulator Water Utility Source: EU, Environment Agency, Anglian Water 8

9 Environmental regulator s drought management plan Source: Environment Agency 9

10 Water utility drought management plan: potential drought situation Source: Anglian Water 10

11 Water utility drought management plan: during drought conditions Source: Anglian Water 11

12 Translation of hydrological and other information into determination of an ongoing drought situation Source: Environment Agency 12

13 European level drought indicator use (1) hydrological indicator use water scarcity/availability indicator use Similar EEA information on water scarcity and drought indicators is available relating to meteorological, agricultural, adaptation & mitigation, water abstraction, economic and environmental issues Source: European Environment Agency 13

14 European level drought indicator use (2) Examples of existing indicators used by Member States to identify and manage droughts... UK, Spain, Portugal, Finland, Italy, Netherlands and France have presented drought indicators there are two main types of indicators, those that are used to prepare for an event and those which make it possible to characterise the event all indicators require a complex combination of different parameters and numerous samplings and monitoring systems..... there is a need for a good and complete indicator system to compare and define droughts parameters included... may vary from one country to another... to integrate the specifics of different climatic and geographic conditions it is often not possible to use the single rainfall factor to identify and manage a drought... Source: European Commission 14

15 Drought indicators outside the event management period River Thames basin hydrological indicators during a long drought periods below long term averages shaded in red England & Wales Aridity Index 3.5 long term England & Wales aridity index based on summer (April- September) rainfall and temperature anomalies Source: Marsh, Cole & Wilby,

16 Seasonal and longer outlooks (1) UK Met Office seasonal precipitation outlook UKCP 09 rainfall scenarios under anthropogenic climate changes generated river flow changes using a single climate model Source: UK Met Office, CEH Wallingford generated river flows using output from range of climate models 16

17 Seasonal and longer outlooks (2) mapping of groundwater drought susceptibility in chalk aquifer (white) red - highest susceptibility; yellow moderate surface water increased sensitivity to environmental derogation groundwater potential for poorer yields Source: British Geological Survey 17

18 Some concluding remarks relating to the wider use of hydrological drought indices Compelling need for evaluation of a range of drought indices [& drought forecasting methods] for potential use beyond their original destination Fitness for purpose is the key concern, together with early availability: standard hydrological indicators have advantages but may not override local issues of availability, applicability etc Future indices may show greater use of remotely-sensed data and modelgenerated data, augmenting conventional observations Indices do not remove the need for sound judgement 18 further information: anncalver@lwrc.co.uk