Uncertainty and theUncertainty and theManagement ofManagement ofthe Cedar Riverthe Cedar River

Presented by Bruce Bachen, Rand Little,

and George Schneider

Water Management SectionSeattle Public Utilities

May 13, 2003

The Cedar RiverThe Cedar River

• Water Supply for one million peopleWater Supply for one million people

• Key Habitat for chinook, coho, Key Habitat for chinook, coho, sockeye salmon and steelhead troutsockeye salmon and steelhead trout

• Site of the largest sockeye run in the Site of the largest sockeye run in the state, and the Landsburg sockeye state, and the Landsburg sockeye hatcheryhatchery

Stream Flow Management: Stream Flow Management: Protecting Instream ResourcesProtecting Instream Resources

• Seattle’s water storage and diversion Seattle’s water storage and diversion activities have a substantial effect on stream activities have a substantial effect on stream flows in the lower Cedar Riverflows in the lower Cedar River

• Stream flow is a key component of the Stream flow is a key component of the aquatic/riparian ecosystem that supports aquatic/riparian ecosystem that supports salmon and many other speciessalmon and many other species

• Social values and species protection priorities Social values and species protection priorities change over timechange over time

• The applied science of stream flow The applied science of stream flow management is complex, relatively new, and management is complex, relatively new, and continues to evolvecontinues to evolve

Meet sockeye mitigation Meet sockeye mitigation responsibilities by:responsibilities by:

Managing a hatchery to produce more sockeye and provide additional fishing

opportunity while minimizing risks to naturally spawning salmon populations and

the ecosystem

Water Management - Water Management - ContextContext

•Multiple ObjectivesMultiple Objectives

•VulnerabilityVulnerability

•Hydrologic UncertaintyHydrologic Uncertainty

Multiple Objectives Create the Multiple Objectives Create the Tension of Competing DemandsTension of Competing Demands

• Water SupplyWater Supply

• Instream FlowsInstream Flows

• Reservoir Management for Resident Reservoir Management for Resident

SpeciesSpecies

• Flood ControlFlood Control

• HydropowerHydropower

VulnerabilityVulnerability

• A Reflection of the Sensitivity of the A Reflection of the Sensitivity of the System and its Beneficiaries (people System and its Beneficiaries (people and environment) to variable and environment) to variable conditionsconditions

Hydrologic Uncertainty-Imaginary Hydrologic Uncertainty-Imaginary WorldWorld

• If the hydrology affecting the system If the hydrology affecting the system

were 100% predictable, the system were 100% predictable, the system

could be operated “perfectly”could be operated “perfectly”

Hydrologic Uncertainty - Real Hydrologic Uncertainty - Real WorldWorld

• Weather is highly variable and somewhat Weather is highly variable and somewhat

unpredictableunpredictable

• Climate is variable and may be changingClimate is variable and may be changing

• Physical processes affecting hydrology arePhysical processes affecting hydrology are

complexcomplex

Strategies for Decision Making Strategies for Decision Making in the Face of Hydrologic in the Face of Hydrologic UncertaintyUncertainty• Making Sense of the PastMaking Sense of the Past

• Real-time Information GatheringReal-time Information Gathering

• ForecastingForecasting

• Communication with StakeholdersCommunication with Stakeholders

• Operational FlexibilityOperational Flexibility

• Risk SharingRisk Sharing

Making Sense of the PastMaking Sense of the Past

• Range of variability, statistical analysesRange of variability, statistical analyses

• Affords Comparisons to Current ConditionsAffords Comparisons to Current Conditions

and Development of Possible Futuresand Development of Possible Futures

• Physical Processes and response of Physical Processes and response of

WatershedWatershed

• Learning from Prior Successes and FailuresLearning from Prior Successes and Failures

Real-time Information Real-time Information GatheringGathering

• WeatherWeather

• Water UseWater Use

• Fish and WildlifeFish and Wildlife

• SnowSnow

• StreamflowStreamflow

ForecastingForecasting

•WeatherWeather

•StreamflowStreamflow

•Climate, ENSO/PDOClimate, ENSO/PDO

Communication with Communication with StakeholdersStakeholders• Greater Knowledge of Conditions, IssuesGreater Knowledge of Conditions, Issues and Valuesand Values

• Better Understanding of Consequences Better Understanding of Consequences ofof

DecisionsDecisions

• Risk Sharing and Decision SharingRisk Sharing and Decision Sharing

Operational FlexibilityOperational Flexibility

• Dynamic Reservoir Rule CurvesDynamic Reservoir Rule Curves

• Hydrologically-linked Instream FlowHydrologically-linked Instream Flow

Obligations Obligations

High Reliability StandardHigh Reliability Standard