Estimated Calibration Parameters in SWAT Model for Andean Watersheds

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1 Estimated Calibration Parameters in SWAT Model for Andean Watersheds Jefferson Valencia Gómez Decision and Policy Analysis July 18 th, 2013

2 Ecosystem Services Team Marcela Quintero Ecologist, Soil and Water Scientist Natalia Uribe GIS Expert and Hydrological modeler Jefferson Valencia GIS expert and Hydrological modeler

3 Objectives To summarize research findings in the calibration process for the simulation of six basins hydrology in the Andean region. To provide information about what the common parameters of the calibration process are and the likely range of parameters values for this region.

4 Localization of the Studied Basins Riogrande II Fúquene Guavio Fraile Quijos Cañete SWAT 2005

5 Andean Basins Characteristics Andean watersheds are characterized by significant landscape diversity in terms of soil type, land use and relief. These factors, when combined with changes in climate along the altitudinal gradient, create different hydrological responses within the same basin. This diversity presents difficulties for hydrological models aimed at simulating streamflow behavior.

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10 Description of the Study Areas Country Watershed Area a (Km 2 ) Mean precipitation b (mm) Number of sub-basins Elevation range (msl) Land use c (%) Fraile SUGC (45) BROM (18) MESQ (18) SWRN (13) RYEG (2) Colombia Fuquene RYEG (56) APPL (11) POTA (10) PINE (7) FESC (5) Guavio RNGB (29) FRSF (16) FESP (15) FRST (15) RYEG (9) Riogrande II RYEG (62) RYEE (16) MESQ (10) PINP (6) FESC (4) Ecuador Quijos FRST (29) PAST (24) WPAS (21) MESQ (11) SWRN (10) Perú Cañete MESQ (29) RYEG (19) RNGB (18) FESC (14) BLUG (13) a Modeled area b Average annual basin value c Extracted from USGS land use database, homologated or adjusted using dominant land use for each basin. APPL: Fruits and permanent crops, BLUG: Grassland/Tundra, BROM: Vegetation in high zone, FESC: Puna grassland, FESP: Paramo and subparamo vegetation, FRCB: Deciduous and subdeciduous forest, FRSF: Fragmented forest, FRST: Forest-Mixed, MESQ: Shrub and/or herbaceous vegetation associations, OAKB: Oak forest, PAST: Clean pasture, PINE: Planted forest, PINP: Pinus patula, POTA: Potato, RNGB: Sparsely vegetated areas, RYEE: Weedy grasses, RYEG: Patterns of permanent crops and pastures, SIDM: Induced pasture, SPAS: Cultivated pasture, SUGC: Sugarcane, SWRN: Patterns of permanent crops, pastures and natural areas, WATR: Water, WPAS: Winter Pasture

11 Spatial Input Data Used in Each Basin Data type Description Watersheds Fraile Fuquene Guavio Riogrande II Quijos (Ec) Cañete (Pe) Topography map Land use map Soils map Resolution 30m 30m 10m 12.5m 90m 90m Source CVC CAR CORPOGUAVIO EPM SRTM-CIAT SRTM-CIAT Scale 1: : : : : : Source IGAC IGAC IGAC IGAC Ecobona IGN Scale 1: : : : : : Source CVC-IGAC IGAC IGAC IGAC INIAP ONERN-CORLIMA Weather No. Stations Source CVC- IDEAM SCS-CN method Surface runoff Hargreaves method Potential evapotranspiration 50 and 100 Ha Threshold for the delineation of basins 5 ranges Slope CAR-IDEAM IDEAM EPM - IDEAM INAMHI SENAMHI

12 Characteristics of the Catchment Area for Calibration Process Watersheds Sub-basin used for calibration Area a Km 2 % Simulation period b No. months simulated No. months with observed streamflow data Fraile Jan-91 - Dec Fuquene Jan-01 - Dec Guavio Jan-95 - Dec Riogrande II Jan-96 - Dec Quijos (Ec) Jan-93 - Dec Cañete (Pe) Jan-92 - Jul a Calibrated area and percentage of the total area of the watershed b This period doesn't include warm up period

13 Parameters Modified in the Calibration Process Name Definition Range SWAT Deafault Value Fraile Fuquene Guavio Riogrande II SHALLST.gw Initial depth of water in the shallow aquifer [mm] GW_DELAY.gw Groundwater delay [days] ALPHA_BF.gw Baseflow alpha factor [days] GWQMIN.gw Threshold water depth in the shallow aquifer for flow [mm] REVAPMN.gw Threshold water depth in the shallow aquifer for "revap" [mm] RCHRG_DP.gw Deep aquifer percolation fraction GWHT.gw Initial groundwater height [m] GW_SPYLD.gw Specific yield of the shallow aquifer [m 3 /m 3 ] ESCO.hru Soil evaporation compensation factor EPCO.hru Plant uptake compensation factor SLSUBBSN.hru Average slope length [m] Changes for HRU -9** SLOPE.hru Average slope steepness [m/m] Changes for HRU +20%** TIMP.bsn Snow pack temperature lag factor SMFMX.bsn Melt factor for snow on June 21 [mm H2O/ C-day] SMFMN.bsn Melt factor for snow on December 21 [mm H2O/ C-day] SFTMP.bsn Snowfall temperature [ C] SMTMP.bsn Snow melt base temperature [ C] ESCO.bsn Soil evaporation compensation factor FFCB.bsn Initial soil water storage expressed as a fraction of field capacity water content Quijos (Ec) Cañete (Pe) SURLAG.bsn Surface runoff lag time [days] SOL_AWC.sol Available water capacity [mm H20/mm soil] 0-1 Changes for Soil +14.4% CH_N2.rte Manning's nvalue for main channel CN2.mgt Initial SCS CN II value Changes for HRU -19% PLAPS.sub Precipitation lapse rate [mm/km] TLAPS.sub Temperature lapse rate [ C/km] BLAI.crop.dat Maximum potential leaf area index Changes for Crop 3* *Just modified to Paramo vegetation (FESP) **Parameters modified to subbasins 1-9

14 Parameters Modified in the Calibration Process Name Definition Range SWAT Default Value Fraile Fuquene Guavio Riogrande II Quijos (Ec) Cañete (Pe) SHALLST.gw Initial depth of water in the shallow aquifer [mm] GW_DELAY.gw Groundwater delay [days] ALPHA_BF.gw Baseflow alpha factor [days] GWQMIN.gw Threshold water depth in the shallow aquifer for flow [mm] REVAPMN.gw Threshold water depth in the shallow aquifer for "revap" [mm] RCHRG_DP.gw Deep aquifer percolation fraction GWHT.gw Initial groundwater height [m] GW_SPYLD.gw Specific yield of the shallow aquifer [m3/m3]

15 Parameters Modified in the Calibration Process Name Definition Range SWAT Default Value Fraile Fuquene ESCO.hru Soil evaporation compensation factor EPCO.hru Plant uptake compensation factor Guavio Riogrande II SLSUBBSN.hru Average slope length [m] Changes for HRU -9** SLOPE.hru Average slope steepness [m/m] Changes for HRU +20%** TIMP.bsn Snow pack temperature lag factor SMFMX.bsn Melt factor for snow on June 21 [mm H2O/ C-day] SMFMN.bsn Melt factor for snow on December 21 [mm H2O/ C-day] SFTMP.bsn Snowfall temperature [ C] SMTMP.bsn Snow melt base temperature [ C] ESCO.bsn Soil evaporation compensation factor FFCB.bsn Initial soil water storage expressed as a fraction of field capacity water content Quijos (Ec) Cañete (Pe) SURLAG.bsn Surface runoff lag time [days] SOL_AWC.sol Available water capacity [mm H20/mm soil] 0-1 Changes for Soil +14.4% CH_N2.rte Manning's nvalue for main channel CN2.mgt Initial SCS CN II value Changes for HRU -19% PLAPS.sub Precipitation lapse rate [mm/km] TLAPS.sub Temperature lapse rate [ C/km] BLAI.crop.dat Maximum potential leaf area index Changes for Crop 3* *Just modified to Paramo vegetation (FESP) **Parameters modified to subbasins 1-9

16 Model Performance Evaluation Fraile Fuquene Guavio Riogrande II

17 Model Performance Evaluation Quijos (Ec) Cañete (Pe) Watersheds Calibration period Validation period NSE d RMSE MAE NSE d RMSE MAE Fraile Fuquene Guavio Riogrande II Quijos (Ec) Cañete (Pe) NSE: Nash-Sutcliffe coefficient of efficiency. From - to 1, being 1 the optimal value. A value of 0.5 is acceptable. d: Index of agreement. Varies between 0 and 1, being 1 perfect agreement, 0 no agreement at all. RMSE: Root mean square error MAE: Mean absolute error

18 Results Range of input values to SWAT for aquifer parameters in the Andes basins: Name Definition Range SWAT Default Value Proposed Range SHALLST.gw Initial depth of water in the shallow aquifer [mm] GW_DELAY.gw Groundwater delay [days] ALPHA_BF.gw Baseflow alpha factor [days] GWQMIN.gw Threshold water depth in the shallow aquifer for flow [mm] REVAPMN.gw Threshold water depth in the shallow aquifer for "revap" [mm] RCHRG_DP.gw Deep aquifer percolation fraction GWHT.gw Initial groundwater height [m] GW_SPYLD.gw Specific yield of the shallow aquifer [m 3 /m 3 ]

19 Conclusions Most of the parameters that need to be often adjusted are those associated with the simulating of water movement in the shallow or unconfined aquifers, surface runoff and snow melting (when applicable). The final values for those parameters related to aquifers are in a range that should be used as a reference for future applications of the SWAT model in the region. These parameters correspond to those related with processes and basins characteristics that are not well studied and understood in the Andes.

20 Thanks for your attention Jefferson Valencia Gómez