1. Evaluating Hydrological Output of DRAINMOD from Measured and Estimated Soil Properties Advisor: Dr. Christopher Hay Presenter: Govinda Karki Graduate Research Assistant Agricultural and Biosystems Engineering July 29, 2015

2. Introduction  DRAINMOD Requires soil properties input: Saturated hydraulic conductivity (Ks) Soil water characteristics curve (SWCC) Drainage Volume Upward flux Green-Ampt Parameters  Input for DRAINMOD : Soil Properties (SWCC and Ksat) determined by:  Direct Method (Field Methods)  Indirect Method ( Pedotransfer Functions, PTFs :Rosetta) Derived from SWCC

3. Introduction  Direct Method:  Hyprop (Wind and Schindler evaporation method) and WP4C (dew point potentiometer) instruments (Peters and Durner 2008).  Indirect Method:  Widely used PTF is Rosetta (Schaap et al. 2001) and uses five different levels of input:  H1: USDA textural class  H2: H1 plus % of sand silt and clay  H3: H2 plus dry bulk density  H4: H3 plus water content at suction -33kPa (field capacity)  H5: H4 plus water content at -1500kPa (wilting point)  DRAINMOD has inbuilt utilities to convert soil properties in formatted input file using Rosetta Hyprop WP4C

4. Objectives  To determine soil properties (Ksat and SWCC) using pedotransfer function (Rosetta), and Hyprop and WP4C  Compare DRAINMOD hydrological output of direct measurement (hyprop & WP4C) and Rosetta inputs with Calibrated values

5. Materials & Methods Study Area  Location: Located at SERF (Beresford, Clay Co., SD)  Soil Type: Trent Series (EhA), Silty clay loam  Climate (1950-2012): Average annual precipitation : 642 mm Average daily maximum Temp: 14.7 ºC Average daily minimum Temp: 1.8 ºC  Field plots 14.25 acre (5.75ha) 6-plots half of the plots were drained and rest was undrained

6. Materials & Methods Soil Information:  USDA, NRCS (SSURGO) soil database used in Rosetta for SWCC  Soil water characteristics curve was generated using Hyprop-DES Measured SWCC Water Content(θ)Head(h) 0.400 0.38-26 0.36-51 0.35-74 0.33-102 0.30-155 0.28-205 0.25-310 0.21-514 0.16-1028 0.12-2588 0.10-5164 0.08-10328 0.07-15000 Saturated Hydraulic Conductivity (K sat,cm/hr.) DepthValue of K sat 0-201.74 20-451.74 45-1101.74 110-1521.74 Measured and Rosetta derived soil parameters for DRAINMOD input Rosetta derived SWCC Water Content(θ)Head(h) 0.4910 0.460-25 0.430-50 0.407-75 0.388-100 0.361-150 0.341-200 0.308-330 0.283-500 0.246-1000 0.183-5000 0.155-15000 Saturated Hydraulic Conductivity (K sat,cm/hr.) DepthValue of K sat 0-433.24 43-713.24 71-1193.24 119-1323.24 132-1520.97

7. Materials & Methods Model Simulation: DRAINMOD simulation for 2004-2014 using measured weather data and soil hydraulic properties (calibration of model) Long-term simulation (1950-2012) conducted for hydrological output Simulation conducted using Rosetta (Ro) Simulation conducted using Direct Measurement (Mo) [ SWCC, Ksat from hyprop-DES] Soil temperature (Freezing and Thawing) was considered for simulation Statistical Analysis: Nash-Sutcliffe efficiency (E): Normalized root mean square (RMSE): Mean absolute error (MAE):

8. Results Comparison of Average Annual Drainage and Annual Runoff Average annual DrainageAverage annual Runoff Co- Calibrated ValuesMo- Direct Measured valuesRo- Rosetta values

9. Results Comparison of Calibrated with Simulated Drainage flow (Nash-Sutcliffe and R2) – Yearly Values

10. Results Comparison of Calibrated with Simulated Drainage flow (Nash-Sutcliffe and R2) – Monlthy Values

11. Results Comparison of Calibrated with Simulated Drainage flow (Nash-Sutcliffe and R2) – Daily Values

12. Results Comparison of Calibrated with Simulated Runoff flow (Nash-Sutcliffe and R2) – Yearly Values

13. Results Comparison of Calibrated with Simulated Runoff flow (Nash-Sutcliffe and R2) – Monthly Values

14. Results Comparison of Calibrated with Simulated Runoff flow (Nash-Sutcliffe and R2) – Daily Values

15. Results Statistical comparison between Mo and Ro for Drainage and Runoff Soil Input YearlyMonthlyDaily DrainageRunoffDrainageRunoffDrainageRunoff E RMSE(cm) MAE(cm) E RMSE(cm) MAE(cm) E RMSE(cm) MAE(cm) E RMSE(cm) MAE(cm) E RMSE(cm) MAE(cm) E RMSE(cm) MAE(cm) Ro 0.970.650.370.750.980.43 0.94 0.04 0.75 0.25 0.03 0.91 0.01.001 0.580.04 0.001 Mo 0.99 0.26 0.15 0.980.200.07 0.99 0.08 0.02 0.98 0.060.01 0.97 0.007 0.001 0.94 0.01 0.003 E- Nash-Sutcliffe efficiency RMSE- Root Mean Squared ErrorMAE- Mean Absolute Error

16. Summary DRAINMOD Output obtained using SWCC from Hyprop & WP4C and Ksat from Hyprop-DES gives fairly close result compared to calibrated values DRAINMOD output obtained from hyprop& WP4C (for SWCC) and Hyprop-DES (for K sat ) fits better than Rosetta Rosetta-derived soil input can be used in DRAINMOD for long-term simulation Statistical measure of average drainage output fits better than average runoff

17. Acknowledgements East Dakota Water Development District South Dakota Corn Utilization Council South Dakota Ag Experiment Station With additional in-kind support provided by Agri Drain Corp. and ADS, Inc.

18. For more questions /details : govinda.karki@sdstate.edu