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Modeling of a Watershed. Basic Calibration Workshop LMRFC March 10-13, 2009. slide 1. NWS Hydrologic Modeling. Operations Table Snow model A Rainfall-runoff model A Unit hydrograph A
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Modeling of a Watershed Basic Calibration Workshop LMRFC March 10-13, 2009 slide 1
NWS Hydrologic Modeling Operations Table Snow model A Rainfall-runoff modelA Unit hydrograph A Convert discharge to stage 1 Display results 1 Rout hydrograph1->2 Snow model B Rainfall-runoff model B Unit hydrograph B Add hydrographs 1+2 Convert discharge to stage 2 Display results 2 Basin A 1 Basin B 2
Requirements • Need models of all process, natural or man-made that occur in a watershed, or adjust the data to remove the effects • Snow accumulation and melt • Soil moisture retention and movement • Flow in channels • Effects of reservoirs • Channel losses • Need ability to combine models in the proper sequence to simulate what occurs in the watershed • Need ability to combine results of models by adding, subtracting, weighing, etc. • Need ability to display results in form of plots, tables, statistics • Data for models • Time series of single quantities • ‘time series’ of gridded values such as precipitation • Operationally, may need to apply state adjustment procedures NWS Calibration Workshop, LMRFC March, 2009 slide 2
NWSRFSOperations Table Concept • Operation • Hydrologic or hydraulic model • Updating procedure • Display of results (graphical or tabular) • Data manipulation algorithm • Operations table • Procedure for combining operations in whatever sequence is needed for a particular application. • Information passed from one operation to another by time series • All input time series for each operation must have data values • Future: pass information from one operation to another in the form of grids NWS Calibration Workshop, LMRFC March, 2009 slide 3
Summary of NWSRFS Operations • Snow model • Conceptual rainfall/runoff models: Sac, Nile • Empirical rainfall/runoff models: 7 variations of API • Channel response functions (UHG) • Hydrologic routing models: Lag/K, layered coefficient, Muskingum • Hydraulic (full dynamic) channel routing • Reservoir models • Stage discharge conversions • Time series manipulation • Add • Subtract • Change t • Mult/divide • No missing • Weight • Updating procedures: Kalman filtering • Glacier model • Consumptive use • Plotting functions NWS Calibration Workshop, LMRFC March, 2009 slide 4