Development of the Hydrologic Model

Transcription

1 Kick-off meeting on enhancing hydrological data management and exchange procedures Water and Climate Adaptation Plan (WATCAP) for Sava River Basin Development of the Hydrologic Model David Heywood Team Leader COWI AS 7 th June 213

2 Sava Basin Hydrologic Model Scope of work Model development define model structure according to the requirements collect necessary data model calibration and verification Creation of forecast scenarios create scenarios for 22, 23, and 25 at gauging stations based on the results of the Exeter study (climate scenarios were later redefined for periods and ) perform forecast s 2 7TH JUNE 213

3 Model Development Choice of the model: HEC-HMS used initially by US Army Corp of Engineers (USACE) as a link to the hydraulic model developed for ISRBC easily obtainable by future users on the Sava River Basin (free of charge) Main pros and cons moderate data requirements (depending on calculation methods) not completely suitable for continuous 3 7TH JUNE 213

4 Model Development Daily time step max time step in HEC-HMS a compromise to satisfy requirements on both water balance and high and low water levels final choice: 12-hour computational time step to resolve time shift in daily input data and enable more realistic hydrologic routing 4 7TH JUNE 213

5 Model Development Sub-basin runoff modelling in HEC-HMS 1. precipitation interception by vegetation (Canopy method) 2. surface detention (Surface method) 3. infiltration (Loss method) 4. direct runoff hydrograph composition (Transform method) 5. baseflow hydrograph composition (Baseflow method) River reaches: Muskingum routing 5 7TH JUNE 213

6 Data Requirements Input data daily precipitation (time series) daily temperatures (time series) monthly potential evapotranspiration (seasonal distribution) Hydrologic data for calibration and verification mean daily flows (time series) Geographic data basin area met station elevations elevation distribution within the basin (elevation bands) 6 7TH JUNE 213

7 Model Development Basin subdivision with respect to daily time step and to data availability and quality: subbasin sizes approx. 2-5 km 2 data quality (reliable measurements, no gaps); recommendations by riparian experts choice of subbasins and modelling methods, and data collection = iterative process select subbasins ask for data select time period select modelling method 7 7TH JUNE 213

8 Calibration and Verification Selection of calibration and verification periods 5-year periods according to the smallest departures from the means for verification calibration Savinja Laško Savinja Laško 8 7TH JUNE 213 Mean annual flow (m3/s) Mean ann. flow 1 Multiyear average MA year

9 Data Collection Data available from Task 1 (trend analysis) total of 33 meteorological (meteo) and 38 hydrologic stations (flows, precipitation, temperatures, Evaporation/calculated Potential. Evapo-transpiration (PET), humidity; daily data) Data from ISRBC GeoHMS input and output from the USACE model, including a raw digital elevation model (DEM) and vectorized river network Sub-basin division made by USACE had to be changed 9 7TH JUNE 213

10 Data Collection Data collection by riparian experts lasted for 5 months (from 5 June to 24 October 212) delivered: hydrologic data at selected stations and in selected periods daily flow rates precipitation and air temperature data at selected meteo station daily data potential evapotranspiration data at selected stations monthly data basic information on water control facilities Precipitation and temperature data from Montenegro additional data needed for the Drina Basin model obtained via ISRBC made available in February TH JUNE 213

11 Data Collection MS Access database: 3,286,698 records 9 Number of stations in database 8 7 Number of stations Discharge Precipitation 1 Temperature TH JUNE 213

12 Model Development Methods selected for continuous modelling in HEC-HMS Simple canopy method Simple surface method Deficit and constant Clark Unit Hydrograph transform method Constant monthly baseflow method or the recession method Muskingum routing method Soil Moisture Accounting Method (SMA) loss method considered, but abandoned due to large number of parameters 12 7TH JUNE 213

13 7th June Model Development Sub-basins Major sub-basins modelled separately

14 7th June Calibration Zagreb 2 okt 1979 okt 198 okt 1981 okt 1982 okt Mackovac okt 1979 okt 198 okt 1981 okt 1982 okt 1983 Sl. Brod 1 5 okt 1979 okt 198 okt 1981 okt 1982 okt 1983 Mean monthly flows

15 7th June Validation 8 Zagreb okt 1969 okt 197 okt 1971 okt 1972 okt 1973 Mackovac okt 1969 okt 197 okt 1971 okt 1972 okt 1973 Sl. Brod okt 1969 okt 197 okt 1971 okt 1972 okt 1973 Mean monthly flows

16 7th June Calibration Seasonal distribution Zagreb year average monthly flows Mackovac Sl. Brod

17 7th June Validation 5-year average monthly flows Zagreb Mackovac Sl. Brod

18 7th June Model Quality (selected stations) 25% 2% 15% 1% 5% % -5% -1% -15% -2% Percentage error in mean flows Calibration Validation

19 7th June Model Quality (selected stations) 1,9,8,7,6,5,4,3,2,1 Nash-Sutcliffe model efficiency coefficient for monthly flows Calibration Validation

20 Further Steps Simulations with climate scenarios: verification of model performance with future climate data for the period s with future climate data for the and periods 2 7TH JUNE 213

21 Thank you for your attention! 21 7TH JUNE 213