ASAE/ASABE EP621 PDF download

ASAE/ASABE EP621 – Guidelines for Calibrating, Validating, and Evaluating Hydrologic and Water Quality (H/WQ) Models

Hydrologic and water quality (H/WQ) models consist of interrelated assemblages of mathematical equations thatrepresent the processes governing the movement, fate, and transport of water, sediments, nutrients, pesticides,bacteria, and other constituents in and on the surface of the soil and through groundwater, stream, river, andreservoir systems. Reliable models provide information for making sound management, policy, and regulatorydecisions. While calibration, validation, and evaluation (CV&E) are essential for ensuring model accuracy andprecision, there is little consistency in how model practitioners conduct and document this process andcommunicate the results. Therefore, this Engineering Practice was designed to contribute to good modelingpractice recommendations to improve modeling methodology and application of H/WQ models through improvedmodel performance as well as enhanced communication of the processes utilized and results to modelers,decision-makers, and other modeling stakeholders.

It builds on recommended protocols recognizing the need for formal model development, application, andcommunication guidelines rather than ad hoc approaches because of the often-serious human health, regulatory,ecological, socio-economic, and policy implications of modeling applications. This Engineering Practice is notmeant to serve as a comprehensive guide but rather to compile and enhance guidance from foundationalmanuscripts such as Beck (1987), ASCE (1993), Haan et al. (1995), Refsgaard et al. (2005), Jakeman et al.(2006), Engel et al. (2007), Moriasi et al. (2007), Biondi et al. (2012), Bennett et al. (2013), Ritter and Mu?oz-Carpena (2013) and Black et al. (2014), and advances described in recent compilations (e.g., Mu?oz-Carpenaet al., 2006; Moriasi et al., 2012, 2015a).