Review of hydrologic models for forest management and climate change applications in British Columbia and Alberta

This review summarizes the capabilities and limitations of existing hydrologic models for use in an operational forest management context in British Columbia (BC) and Alberta (AB). The review brings together relevant information contained in user manuals, technical model documentation, and in published materials that describes model applications, and emphasizes studies conducted in the Pacific Northwest and in physical and climatic settings similar to those encountered in BC and AB. One outcome of this review is to provide guidance (decision support) for resource managers and other practitioners to help them identify which hydrologic models are most appropriate for addressing their forest management questions. To do this, the review identifies trade-offs between model complexity and model functionality for addressing forest management questions and makes recommendations for advancing the routine and consistent use of watershed models. These recommendations include improving interdisciplinary education; performing model inter-comparisons at data-rich (experimental) and data-poor (ungauged) watersheds; enhancing data availability; communicating uncertainty in results; developing better models, graphical user interfaces (GUIs), commercial software, and model support; and establishing regulatory guidance and professional precedence. The review also considers the suitability of select models for exploring the potential effects of climate change on future watershed processes that are relevant to forest management. Emphasis is placed on shifts in site water balances (evapotranspiration); changes in snow accumulation and melt rates; melting of permafrost, river, and lake ice processes; adjustments in glacier mass balance; changes in streamflow generation; and the increased risk of disturbances such as wildfire, pest outbreaks (e.g., mountain pine beetle), flood events, windthrow, and landsliding. The barriers and challenges to using hydrologic models for answering climate change questions are discussed, and areas for model improvement are identified.