A Hydrologic/Water Quality Model Applicati1¹

Abstract

This paper presents a procedure for standard application of hydrologic ⁄ water quality models. To date, most hydrologic ⁄ water quality modeling projects and studies have not utilized formal protocols, but rather have employed ad hoc approaches. The procedure proposed is an adaptation and extension of steps identified from relevant literature including guidance provided by the U.S. Environmental Protection Agency. This protocol provides guidance for establishing written plans prior to conducting modeling efforts. Eleven issues that should be addressed in model application plans were identified and discussed in the context of hydrologic ⁄ water quality studies. A graded approach for selection of the level of documentation for each item was suggested. The creation and use of environmental modeling plans is increasingly important as the results of modeling projects are used in decision-making processes that have significant implications. Standard modeling application protocols similar to the proposed procedure herein provide modelers with a roadmap to be followed, reduces modelers' bias, enhances the reproducibility of model application studies, and eventually improves acceptance of modeling outcomes.(KEY TERMS: simulation; quality assurance ⁄ quality control; runoff; nonpoint source pollution.) Engel, Bernard, Dan Storm, Mike White, Jeff Arnold, and Mazdak Arabi, 2007. A Hydrologic ⁄ Water Quality Model Application Protocol.

Impacts of climate change on nutrient losses from the Pike River watershed of southern Québec

“…This is probably because models are often optimized for conditions prevailing during the calibration period, which may differ significantly from the validation period. In this study, the wetter conditions and more intense hydrologic events prevailing during the validation (vs. calibration) period might explain why some CPs were below the recommended value during the validation period (Engel et al 2007). The weaker validation performance does not invalidate the suitability of the model for simulated processes, but raises awareness of the difficulties associated with simulating sediments and nutrient loads during intense hydrological events and the potential impacts on future projections.…”

“…Except for the validation of NO 3 ( , low NSE values were always above 0 and close to 0.5. Engel et al (2007) pointed out that the acceptability criteria might be lowered depending on the project objectives.…”

Regionalization of SWAT Model Parameters for Use in Ungauged Watersheds

“…While there is no consensus on specific Nash-Sutcliffe coefficient values that must be obtained for SWAT predictions to be considered good, a value greater than 0.5 is considered acceptable [38][39][40], and in particular considering monthly simulations [38,39]. Based on other documentation, NS values greater than 0.75 signify good model performance, while those between 0.36 and 0.75 signify acceptable model performance [41] (as cited in [42]).…”

Estimating Snow Mass and Peak River Flows for the Mackenzie River Basin Using GRACE Satellite Observations

“…The baseflow was likely to have smaller measurement errors than that for the peak runoff and river flow, as the former represents a seasonal total value while the latter represent values at a daily time step. Typically, model simulations tend to be poorer for shorter time steps than for longer time steps [56]. Smaller measurement errors for the total baseflow may provide advantages for achieving higher NSE.…”