Managing Global Resources for a Secure Future

2017 Annual Meeting | Oct. 22-25 | Tampa, FL

365-10 Impact of Length of Calibration Period on the Apex Model Output Simulation Performance.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Nutrient Source Control at the Field, Farm and Watershed Scales (includes student competition)

Wednesday, October 25, 2017: 1:45 PM
Tampa Convention Center, Room 12

Amanda M Nelson1, Daniel Moriasi2, Mansour Talebizadeh2, Jean L. Steiner3, Rem Confesor Jr.4, Prasanna H. Gowda5, Patrick Starks2 and Haile K. Tadesse6, (1)Grazinglands Research Laboratory, USDA-ARS Grazinglands Research Laboratory, El Reno, OK
(2)Grazinglands Research Laboratory, USDA-ARS, El Reno, OK
(3)7207 W Cheyenne Street, USDA-ARS Grazinglands Research Laboratory, El Reno, OK
(4)National Center for Water Quality Research, Heidelberg University, Tiffin, OH
(5)USDA-ARS Grazinglands Research Laboratory, El Reno, OK
(6)USDA - United States Department of Agriculture, El Reno, OK
Abstract:
Datasets from long-term monitoring sites that can be used for calibration and validation of hydrologic and water quality models are rare due to resource constraints. As a result, hydrologic and water quality models are calibrated and, when possible, validated using short-term measured data. A previous study on the impact of the length of the calibration period on simulation performance of the Agricultural Policy/Environmental eXtender (APEX) model focused on streamflow. This follow-up study used a long-term, water quality data from the Rock Creek watershed, located in northern Ohio, to quantify the impact of length of calibration period on sensitive model parameters and performance of APEX to simulate total nitrogen (TN) and total phosphorus (TP). Five short (5-year), two medium (15-year), and one long term (28-year) calibration period scenarios were implemented. The calibrated parameters for each of the scenarios were applied to the validation period (last 5 years). The most sensitive streamflow, TN, and TP parameters and their values were presented and discussed in detail, as well as model performance results during the calibration and validation periods. Finally, computed uncertainty ranges of simulated streamflow, TN, and TP outputs were presented and discussed. These results are expected to be used by the USDA to develop an APEX model parameter database to support nation-wide deployment of the nutrient tracking tool (NTT), a user-friendly web-based computer program used to estimate reductions in nutrient losses associated with alternative practices.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Nutrient Source Control at the Field, Farm and Watershed Scales (includes student competition)