ESP w/ GFS and CFS

NWS HeadquartersAugust 10, 2011Kevin WernerNWS Colorado Basin River Forecast Center

1CBRFC Decision Support for Colorado River Water Management

1OutlineColorado River Primer

CBRFC Climate Services

Gap and Chasms3

Why the Colorado River Stopped Flowing-All Things Considered, July 14, 2011

Colorado River25 million people rely on Colorado River water3.5 million acres of irrigation85% of runoff comes from above 9000 feetMean annual discharge is about 12.4 MAFStorage capacity is about 60 MAF (4 times mean annual flow)River is fully used and little flows to ocean

Colorado River AllocationColorado Compact (1922) divided water between the upper basin and lower basin 7.5 MAF eachMexican Water Treaty (1944) allocated Mexico 1.5 MAFArizona v. California (1964) allocated water among lower basin statesInterim Guidelines (2007) specify shortages and surpluses through 2026 that are tied to forecastsKey facts:River is over-allocated: original allocation (16.5 MAF) was based on a series of wet years. Actual average flow is 12.4 MAFLower basin states (AZ, CA, NV) use full 7.5 MAF each yearMexico uses its full 1.5 MAFUpper basin states (CO, WY, UT, NM) are still developing their 7.5 MAFNo shortage has ever been declared on the riverShortages would affect lower basin states first (and AZ first of all)

Long Term Supply / Demand6

Interim Operating Guidelines7

14.7 MAF3,6291/1/2011Projection10.3 MAF1,0861/1/2011 ProjectionGuidelines specify how shortages and surpluses will be distributed among the basin statesUSBR directed to operate reservoirs based, to a large extent, on CBRFC/NRCS official forecastsMost years 8.23 MAF released from Lake Powell to Lake MeadIn wet years when Lake Mead is low (such as 2011), extra water can be released. This is called equalization and/or balancing.Most probable release schedule based on CBRFC/NRCS April 1 forecast is 11.63 MAF

ValueDamage from 1/10 AZ storm:$11maDamage from 6/10 UT flooding:$6.5maDamage from 12/10 UT/NV storm:$35maDamage from spring 2011 UT/CO/WY flooding: $4bb

**Economic value of water resources far greater than flooding damages

Sources:a: WFO, FEMA (via stormdata); b: MWD (via Hasencamp, private communication8Water Supply Decision Support

ThepastThefutureEfforts in parallel --

CBRFC working to improve probabilistic flow forecasts

BOR working to implement probabilistic water management modelPast CBRFC MethodsOfficial forecasts coordinated each month with NRCS/NWCCSkill primarily from accumulating snow packUpdated monthly or semi-monthlyProbabilistic but not ensemble basedNot repeatableSubjectiveForecaster Role:Monitor forecast process and systemAdd judgement to forecast process

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Future CBRFC Methods11Objective, repeatable ensemble forecastsIntegrate skill from weather and climate predicationsTailor to stakeholder thresholds and concernsForecaster role:Monitor forecast process and systemApply judgement (less frequently?)Decision supportWork to improve forecast system and processes based on objective standardsFollow best practices identified by CPC

Core Partner: USBRMission: manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American publicOperates major water projects in 17 western statesCBRFC works with 2 of 5 USBR regions (Lower and Upper Colorado)

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Past USBR MethodsUpper and Lower Colorado Regions operate reservoirs based on the 24 month study24 month study:Updated monthlyExtends out 24 monthsSpecifies reservoir releases and target levelsSingle value output (except Aug, Jan, Apr when it has reasonable min and reasonable max)Labor intensive and subjective

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Future USBR MethodMid-Term Probabilistic Model:Uses CBRFC ensemble forecasts for first two yearsUses rules (prioritized logic) to determine releasesOutput will be ensemble forecast for reservoir operationsCurrently undergoing testingExpected deployment by WY2012

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Barriers, Gaps, Chasms15

Common Stakeholder RequirementsMore frequent updates of our long lead productsMore analysis - often involving climate science plus water resourcesMore metadata and data about our forecast process:raw model forecastssnow distributionmodel forcing informationLonger lead forecasts - even with minimal skill 16Institutional BarriersNWS largely unaware of current water supply climate services and the challenges in addressing stakeholder requirementsNo metrics for measuring water supply / resources forecastsNo mechanism for connecting needed climate science to water resources modelingNo method for collecting stakeholder requirements especially those difficult to meetNOAA and NWS personnel resources dispersed and often disconnectedNWS Service Hydrologists disconnected from RFC NOAA and NWS climate science and services efforts unaware of existing RFC climate services and needsRFC staffing profile designed around NWS flood forecasting mission not climate services 17Service Gaps &Science ChallengesSkillful seasonal forecast for Upper Colorado (minimal ENSO signal)2-5 year forecastsWater Demand / ET forecastsProbabilistic streamflow forecasts across time scalesDust on snowBeetle killConnecting forecasts and science to stakeholder decisions

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Chasm19

Colorado River water resources stakeholdersMission: To understand and predict changes in the Earths environment to meet our Nations economic, social, and environmental needs

Questions?Kevin Werner

CBRFC Service Coordination HydrologistPhone: 801.524.5130Email: kevin.werner@noaa.gov20npr co riverKevin WernerKevin Werner's Album2011256670.3eng - iTunNORM 000001B5 00000000 00003B1E 0000001E 00007C2F 00030424 00007EE9 00007EE9 0003CB87 0003CB87eng - iTunSMPB 00000000 00000210 00000828 0000000000ACAA48 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000