Drought and the Drought and the Commonwealth’s Assessment Commonwealth’s Assessment and Response Planand Response Plan

Commonwealth of Virginia

Department of Environmental Quality

Drought????Drought????

Drought????Drought????

Deficiency in precipitation for an extended period of time, generally a season or more

Normal, recurrent feature of climateTemporary in nature as opposed to an

arid climateImpacts are due to the interplay of the

natural event and the societal demands placed on water resources

Types of DroughtTypes of Drought

Meteorological DroughtAgricultural DroughtHydrological DroughtSocioeconomic (Water Supply)

Drought

Executive Order #39, Virginia Executive Order #39, Virginia Water Supply InitiativeWater Supply InitiativeIssued December 13, 2002Assure an adequate supply of clean,

safe drinking water Prepare a preliminary drought

assessment and response plan by April 1, 2003

Drought Response Technical Drought Response Technical Advisory CommitteeAdvisory Committee

Composed of 26 individuals representing federal, state, and local government, agriculture, commercial and industrial, and environmental interests

TAC received technical support from the existing Virginia Drought Monitoring Task Force

TAC met three times in February and March 2003

Draft plan is based on review of Maryland, Pennsylvania, and North Carolina plans

Drought Evaluation RegionsDrought Evaluation Regions

Drought Assessment PlanDrought Assessment Plan Drought conditions will be monitored by the

DMTF Based on four preliminary indicators

– Precipitation Deficits– Streamflows– Ground Water Levels– Reservoir Levels

DMTF will review all other available information when making drought recommendations to the Drought Coordinator

Precipitation DeficitsPrecipitation DeficitsMonthsAnalyzed

Normal(% of NormalPrecipitation)

Watch(% ofNormalPrecipitation)

Warning(% ofNormalPrecipitation)

Emergency(% ofNormalPrecipitation)

October-December

>75.0 <75.0 <65.0 <55.0

October-January >80.0 <80.0 <70.0 <60.0

October-February >80.0 <80.0 <70.0 <60.0

October-March >80.0 <80.0 <70.0 <60.0

October-April >81.5 <81.5 <71.5 <61.5

October-May >82.5 <82.5 <72.5 <62.5

October-June >83.5 <83.5 <73.5 <63.5

October-July >85.0 <85.0 <75.0 <65.0

October-August >85.0 <85.0 <75.0 <65.0

October –September (andprevious 12months)

>85.0 <85.0 <75.0 <65.0

StreamflowsStreamflows

StreamflowsStreamflows

Normal Greater 25th percentile

Drought Watch 10th to 25th percentile

Drought Warning 5th to 10th percentile

Drought Emergency Less than 5th percentile

Ground Water LevelsGround Water Levels

Ground Water LevelsGround Water Levels

Normal Greater 25th percentile

Drought Watch 10th to 25th percentile

Drought Warning 5th to 10th percentile

Drought Emergency Less than 5th percentile

Reservoir LevelsReservoir Levels

•Normal Greater than 120 days storage

•Drought Watch 90 to 120 days storage

•Drought Warning 60 to 90 days storage

•Drought Emergency Less than 60 days storage

Drought DeclarationDrought Declaration

Three stages of drought severity– Drought Watch– Drought Warning– Drought Emergency

Declaration of drought watch and warning by Drought Coordinator

Declaration of drought emergency by the Governor utilizing an executive order

Drought WatchDrought Watch

Climatic conditions indicative that a major drought event is possible

Actions initiated to raise public awareness of potential for onset of drought conditions

Encourage all public water supplies and major water users to review existing or prepare new drought response plans

Drought WarningDrought Warning

Climatic conditions indicative that the onset of a major drought event is imminent

Require implementation of drought response plans

Typical actions would be voluntary water use restrictions

Goal of reducing water use by 5-10%

Drought EmergencyDrought EmergencyDrought has impacted water supplies

to the point that unrestricted use is not possible

Require implementation of mandatory water use restrictions contained in drought response plans

Require mandatory water use restrictions for supplies without drought response plans

Goal of reducing water use 10-15%

Mandatory Water Use RestrictionsMandatory Water Use Restrictions

Unrestricted irrigation of lawns and athletic fields

Unrestricted irrigation of golf coursesWashing paved surfacesUnrestricted vehicle washingOperation of ornamental fountainsUnrestricted use of water for

swimming pools

Water RationingWater RationingMay be required when mandatory use

restrictions are not sufficientIndividual case decision based on

impacts to a particular water supplyDrought Coordinator will work closely to

assure that any available State resources are utilized

Sources of informationSources of informationU.S. Drought Monitor

– http://www.drought.unl.edu/dm/monitor.html

U.S. Drought Monitor- Virginia– http://www.deq.virginia.gov/watersupply/drought.html

U.S. Seasonal Drought Outlook– http://www.cpc.noaa.gov/products/expert_assessment/seasonal_drought.html

National Drought Mitigation Center– http://drought.unl.edu/

Virginia Precipitation – http://www.climate.virginia.edu/

Sources of informationSources of informationVirginia Streamflow and GW levels

– http://waterdata.usgs.gov/va/nwis/rt

Virginia Drought Assessment and Response Plan– http://www.deq.virginia.gov/watersupply/pdf/droughtresponseplan.pdf

Virginia Drought Monitoring Task Force– tdwagner@deq.virginia.gov