Development and Application of a Modular Watershed-Scale Hydrologic Model Using the Object Modeling System: Runoff Response Evaluation

Abstract

This study reports on the integration of the J2K model (an object-oriented, hydrological system for fully distributed simulation of the water balance in large watersheds) under the Object Modeling System (OMS) environmental modeling framework and subsequent evaluation of OMS-J2K performance in the Cedar Creek watershed (CCW) in northeastern Indiana. The CCW is one of 14 benchmark watersheds in the USDA-ARS Conservation Effects Assessment Project (CEAP) watershed assessment study. Two input parameter sets were developed for OMS-J2K evaluation: (1) a parameter with parameter values taken from previous simulation studies where J2K was applied to watersheds with characteristics similar to the CCW, and (2) an parameter with modifications to input parameters related to evapotranspiration, soil water storage, and soil water lateral flow. Comparisons of daily, average monthly, and annual average simulated and observed flows for the 1997-2005 simulation period using the base parameter set resulted in Nash-Sutcliffe efficiency (E NS ), root mean square deviation (RMSD), and relative error (PBIAS) coefficients of 0.34 to 0.48 for E NS , 1.50 to 8.79 m 3 s -1 for RMSD, and -18.43% for PBIAS. All statistical evaluation coefficients improved for the adjusted parameter set (e.g., 0.44 to 0.59 for E NS , 0.87 to 7.73 m 3 s -1 for RMSD, and -8.59% for PBIAS). The ranges of E NS and PBIAS values for uncalibrated or manually adjusted streamflow predictions in this study (using both parameter sets) were similar to others reported in the literature for various watershed models. This study represents the first attempt to develop and apply a complex natural resource system model under the OMS. The results indicate that the OMS-J2K watershed model was able to reproduce the hydrological dynamics of the CCW and should serve as a foundation on which to build a more comprehensive model to better quantify water quantity and quality at the watershed scale. In particular, the topological routing scheme employed by OMS-J2K (thus allowing the simulation of lateral processes vital for the modeling of runoff concentration dynamics) is much more robust than the quasi-distributed routing schemes used by other watershed-scale natural resource models and represents a noteworthy advancement in hydrological modeling toward deriving suitable conservation management scenarios.