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Calibration Strategy Implementation over An Entire River Basin. Gather Information and Data Assess Spatial Variability of Hydrologic Factors Select Flow-Points and Period of Record for Calibration Analyze Historical Data and Put in Form Needed by Models
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Calibration StrategyImplementation over An Entire River Basin • Gather Information and Data • Assess Spatial Variability of Hydrologic Factors • Select Flow-Points and Period of Record for Calibration • Analyze Historical Data and Put in Form Needed by Models • Calibrate Hydrologic Models (Snow, Soil Moisture, River, and Reservoir) • Implement for Operational Use
Calibration Requirements • Knowledge and experience (requires investment in training and time to develop needed skills) • Teamwork --including people with different types of expertise • Leadership to direct, monitor, and review the overall effort • Computerized tools (interactive, graphical, GIS based) available to reduce manual labor • Must follow proven procedures and strategies
Historical Data Analysis • Should be done over a large area to incorporate spatial variability and terrain effects • Results should be as unbiased as possible compared to what actually occurs • Models are not designed to overcome data bias • Data bias will cause model parameters to become distorted and results to be sub-optimal • Model parameters will not be consistent with hydrologic factors over a river basin or RFC area • Historical and operational techniques should be compatible (i.e., produce statistically similar results)
Effect of Data Bias • Precipitation • Effect most noticeable in total amount of runoff generated • % Change in runoff normally greater than % change in precipitation • Temperature • Effect most noticeable in timing of snowmelt runoff and form of precipitation • Small temperature bias significantly effects snowmelt timing. • Evaporation • Mainly effects total amount of runoff generated • Amount greatest in generally wet regions
Effect of MAP on Model ResultsChanging MAP by 10% Leaf River nr Collins MS.
Effect of MAT on Snow ModelChanging MAT by 2 FSmith River nr Bristol, NH – 1970