The Agroecosystem-Watershed (AgES-W) Model: Model Overview and Application to the South Fork, IA USA Watershed.

AgroEcoSystem-Watershed (AgES-W) is a modular, Java-based spatially distributed model which implements hydrologic/water quality (H/WQ) simulation components under the Java Connection Framework (JCF). AgES-W has been previously evaluated for streamflow and recently has been enhanced with the addition of tile drainage, nitrogen (N) and sediment modeling components refactored from various agroecosystem models including J2K-SN, SWAT, WEPP, and RZWQM2. The specific objective of this poster is threefold: 1) present an overview of major AgES-W processes, simulation components, and input/output file structure; 2) evaluate the accuracy and applicability of the enhanced AgES-W model for estimation (using a newly developed autocalibration tool) of streamflow and N/sediment loading; and 3) evaluate the efficacy of AgES-W for assessing spatially targeted agricultural conservation effects on water quantity and quality. The South Fork Watershed (SFW) in central Iowa, USA was selected as the target area for model application. AgES-W model performance was assessed using Nash-Sutcliffe model efficiency (ENS) and percent bias (PBIAS) model evaluation criteria. Comparisons of simulated and observed daily and average monthly streamflow/N loading and monthly sediment load for different simulation periods resulted in ENS and PBIAS values that were within the range of those reported in the literature for other H/WQ models at a similar scale and time step. Considering that AgES-W was applied with minimal calibration, study results indicate that the model reasonably reproduced the hydrological, N, and sediment dynamics of the SFW and should serve as a foundation upon which to better quantify additional water quality indicators (e.g., phosphorus dynamics) at the watershed scale.