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Watershed Assessment: Moving from Indicators to Better Process Understanding and Models
Citation:
Sidle, R. Watershed Assessment: Moving from Indicators to Better Process Understanding and Models. Presented at 2013 Joint Scientific Congress, Saskatoon Saskatchewan, CANADA, May 26 - 30, 2013.
Impact/Purpose:
Presentation given at the 2013 Joint Scientific Congress: Bridging Environmental Science, Policy and Resource Management
Description:
Watershed assessment is a critical approach to evaluate the effects of anthropogenic activities on ecosystem components and humans. Cumulative effects of these stressors in both time and space represent an important challenge in watershed assessment. Many of the indicator approaches that have been used in hydrological and sediment models, like equivalent clearcut area and road density, are inadequate, as are some of the bioindicators. These simply do not effectively link indicator response or change to ecosystem processes. As such, there is a need to move towards a more process-based approach in water assessment with respect to transport of materials (water, sediment, nutrients, and contaminants) and the biota they interact with along their pathways. Distributed, physically-based watershed models are powerful tools that can capture water, sediment and chemical transport and transformations at multiple scales; however, these may be too complicated and time-consuming for site specific assessments. Progress has been made in capturing important watershed processes in simpler hydrology and sediment models, but more research is needed to incorporate cumulative effects of land use. An approach that utilizes complex, spatially-distributed watershed models to inform and develop reduced-form models may be a useful paradigm for regional watershed assessment. For similar biogeographic regions, reduced form models (based on system processes) may be powerful management tools that can inform rural land management, residential planning, and regulation. An example is presented showing how such an approach could be applied to sediment sources, transport, and ecosystem impacts in watersheds of varying sizes, including the temporal and spatial effects of land management activities – e.g., roads, trails, agriculture and forest management disturbances. Furthermore, implications for moving towards improved sustainable watershed management and regulation are addressed.
