Spirit Lake was changed biologically, chemically, and physically by the 1980 eruption of Mount St. Helens and the concurrent landslide that essentially buried the old lake and created a new one in its place. Recent changes to the surrounding watershed, spurred by ever-increasing regrowth of terrestrial vegetation, continue to alter the biogeochemistry of Spirit Lake. Here the authors outline over a decade of work developing a hydrologic and nutrient model for the lake and discuss preliminary work to elucidate the ecological role of the floating logs in Spirit Lake.