Objectives and Approach
The Puget Sound River History Project is a response to the need for a better understanding of the “reference state” of lowland river landscape to support effective river restoration and management in the Puget Sound area: the processes and forms that constitute the physical template, controls on its spatial pattern, its evolution through time, and how it functions as a template for ecosystems. We use three types of studies: landscape evolution, landscape processes and dynamics, and GIS mapping of pre-settlement landscape.
The Holocene landscape evolution
We use digital terrain analysis to understand how the region’s geologic history, particularly Pleistocene glaciation, Holocene lahars, and recent co-seismic uplift and subsidence, shapes valley topography, and how the fluvial response, in turn, generates landscapes with contrasting river morphology and dynamics, floodplain landforms, and ecosystems.
Mapping the historical landscape
To study the forms and spatial patterns of the region’s landscape without the obscuring and homogenizing effects of modern land use, we use 19th century field surveys supplemented with more recent sources, including high-resolution digital elevation models from lidar, in a GIS to map land cover and landforms at the time of early Euro-American settlement in the mid 19th century.
For an application of historical mapping to an analysis of historical change to Puget Sound tidal marshes, see Collins and Sheikh (2005a).
Process studies
We undertake process studies using field sites in protected areas and data from archival sources to better understand landform and ecosystem dynamics, including the dynamic between forests, fluvial wood, and river dynamics in landscape evolution and ecosystem assembly.
Applications
We are developing applications for river management and restoration that include: an approach to defining reference conditions; approaches to characterizing hazards in lowland river valleys; framework for a linked river and riparian forest restoration; historical habitat estimates for historical salmonid production assessments; and environmental change analyses.