MULTI-SCALE MODELING OF THE EFFECTS OF LANDSCAPE AND CLIMATE CHANGES ON INTEGRATED HYDROLOGIC SYSTEMS

Drastic land cover changes have occurred recently in Colorado due to the mountain pine beetle (MPB) infestation, which has destroyed entire forests in a matter of years. This widespread devastation will clearly have an effect on the distribution, availability, and quality of water resources in the state, but the severity and duration of these effects are largely unknown. This work presents a numerical framework that is being used to investigate the effects of the MPB epidemic using multi-scale, numerical models of the hydrologic system of Colorado; the large scale model covers the entire state of Colorado at 1km resolution and the smaller model covers about 6 cells of the larger domain and is based on a small watershed within Rocky Mountain National Park at 20m resolution. The small-scale models can be used for high-resolution transport modeling but also help to quantify the imbedded uncertainty in the large-scale model where the rough terrain is difficult to represent with effective model parameters. At both scales, the models are fully coupled simulations of the vadose zone, groundwater, and surface water systems, which also explicitly simulate land-surface processes. The models can also be directly coupled to atmospheric dynamics models to explicitly simulate weather and climate changes, or to reactive transport models to simulate the changes in geochemistry. This model framework provides a realistic representation of the natural system that is being used to investigate the relative changes in the near- and long-term behavior of the ecohydrologic system due to the MPB infestation in Colorado.