MIKE HYDRO River Rainfall Runoff modelling – overview of RR modelling options Rainfall Runoff modelling Content: • • • • • Catchment delineation – Graphical / manual / Import RR models Options Linkage to HD-models Results © DHI Rainfall Runoff modelling Why Rainfall Runoff modelling? • Calculate catchment runoff from precipitation • Effects of land use change • Climate change studies/coupling with atmospheric models • Forecasting of floods/droughts • Streamflow extension or gap-filling using Meteorological data • Surface water/groundwater interaction • Simulation of spatial patterns within a catchment • Water availability within river basins â DHI Rainfall Runoff Model types MODEL TYPES • Lumped Model-type available in MIKE HYDRO River • Semi-distributed Additional model type characterisation: • Distributed © DHI - Continuous - Event-based MIKE HYDRO River - Rainfall Runoff Models Available Rainfall runoff models : ‘NAM’ (Numerical Runoff Model) • Lumped, Continuous model type ‘UHM’ (Unit Hydrograph Method) • Lumped, Event-based model type ‘Time-area’ • A conceptual model where runoff is controlled by initial and continuous hydrological losses ‘Kinematic wave’ • A non-linear model based on the kinematic wave approach © DHI Rainfall Runoff model : NAM THE RAINFALL-RUNOFF PROCESS © DHI MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) PROCESS DESCRIPTION • Describes the land phase of the hydrological cycle • NAM is a lumped, conceptual model: − Lumped catchment regarded as one unit, parameters are average values − © DHI Conceptual based on considerations of the physical processes The Rainfall Runoff process (NAM) MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) PROCESS DESCRIPTION QOF SNOW SOIL MOISTURE PROFILE Owp Root Zone Overland Flow Pn CK2 RAIN SNOW STORAGE Ofc Osat Ep P U SURFACE STORAGE QIF InterFlow Ea DL Lmax Lmax LOVER ZONE STORAGE L Sy G CAFlux GWPump GWL BFu GWL Depth © DHI OF IF Ps Umax L CK1 CKBF BF BaseFlow GROUNDWATER STORAGE GWLBFo MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) NAM Main parameters Umax Maximum contents of surface storage Evaporation; small peaks Usual value: 10-25 mm Lmax Maximum contents of rootzone storage Evaporation; water balance Usual value: 50-250 mm CQof Overland flow coefficient Divides excess rainfall in runoff and infiltration Usual value: 0.01 - 0.99 TOF Rootzone threshold value for overland flow Delays overland flow at the beginning of a wet season Usual value: 0.0 - 0.7 © DHI MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) NAM Main parameters cont’d: TG Root zone threshold value for recharge Delays groundwater recharge at the beginning of a wet season Usual value: 0.0 - 0.7 CKBF Time constant for routing baseflow Determines shape of baseflow hydrograph Usual value: 500 - 5000 hours CK1 ,CK2 Time constant for routing overland flow Determines shape of peaks Usual value: - 48 hours © DHI MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) NAM CALIBRATION © DHI MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) NAM Calibration MAXIMUM: BUT 15 NAM PARAMETERS PARAMETERS USUALLY FIXED I.E 10 PARAMETERS TO BE CALIBRATED • Most important for the water balance are Lmax, Umax, and CQOF • Remaining parameters are used for adjustment of peaks and for routing © DHI MIKE HYDRO River – Rainfall runoff modelling Activate Rainfall runoff: RR Catchment definitions: a) Delineation (from DEM) b) Digitization c) Shapefile Import © DHI MIKE HYDRO River – Rainfall runoff modelling Combined catchment • Combine outflow from several individual catchments © DHI MIKE HYDRO River – Rainfall runoff modelling NAM calibration plot option • Compare simulation results to measured timeseries • Creates automatically a ‘Plot composer file’ with comparison plots during simulation LIVER, Observed RunOff [m^3/s] LIVER, Simulated RunOff [m^3/s] 7.0 6.0 5.0 4.0 3.0 2.0 C:\MIKE Zero\AutoCalibT es t\RRc alibration\LIVER.dfs0 C:\MIKEZero\AutoCalibT est\RRc alibration\LIVER.dfs0 LIVER, Accumulated Qobs Million [m^3] LIVER, Accumulated Qsim Million [m^3] 100 80 60 40 20 1.0 0.0 00:00 1973-08-20 00:00 1974-03-08 Continuous values comparison © DHI 00:00 09-24 00:00 1975-04-12 00:00 10-29 00:00 1973-08-20 00:00 1974-03-08 Accumulated values comparison 00:00 09-24 00:00 1975-04-12 00:00 10-29 MIKE HYDRO River – Rainfall runoff modelling Coupling of Hydrodynamic and Rainfall runoff models • Catchment connections − • Catchments links to one or multiple rivers River Links − − By fraction or area of catchments Link types: • • • © DHI Point Distritubed Entire branch MIKE HYDRO River – Rainfall runoff modelling • Simulations Results − • All models; Runoff and Rainfall Additional results depending on RR-model selected: Example: NAM Additional Result-file content: © DHI ... important for the water balance are Lmax, Umax, and CQOF • Remaining parameters are used for adjustment of peaks and for routing © DHI MIKE HYDRO River – Rainfall runoff modelling Activate Rainfall runoff: ... on considerations of the physical processes The Rainfall Runoff process (NAM) MIKE HYDRO Basin - Rainfall Runoff Modelling (NAM) PROCESS DESCRIPTION QOF SNOW SOIL MOISTURE PROFILE Owp Root Zone.. .Rainfall Runoff modelling Content: • • • • • Catchment delineation – Graphical / manual / Import RR models Options Linkage to HD-models Results © DHI Rainfall Runoff modelling Why Rainfall Runoff