ARS | Publication request: The Use of Scenario Analysis to Assess Future Landscape Change on Watershed Condition in the Pacific Northwest (USA) 1937

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 26, 2007
Publication Date: February 8, 2008
Citation: Kepner, W.G., Hernandez, M., Semmens, D., Goodrich, D.C. 2008. The Use of Scenario Analysis to Assess Future Landscape Change on Watershed Condition in the Pacific Northwest (USA). In: Use of Landscape Sciences for Environmental Security, Springer Publishers, The Netherlands. pp. 237-261.

Interpretive Summary: The ability to assess, report, and forecast the life support functions of ecosystems is absolutely critical to our capacity to make informed decisions which will maintain the sustainable nature of our environmental services and secure these resources into the future. It is from this perspective that we have used the state of Oregon and particularly the Willamette River basin to demonstrate the integration of advanced technologies (such as satellite remote sensing and land cover characterization, large digital primary datasets, spatial statistics, and process models) with landscape ecological theory to examine impacts in environmental processes. Specifically, this study provides one example of the use of landscape sciences for environmental assessment that examines the impact of both urban and agricultural development in a large regional area in the northwest United States. In particular, it attempts to 1) answer questions that relate to future scenarios that describe contrary positions related to urban development, 2) provide information which can be used to assess the potential changes of the landscape relative to human use, and 3) provide options that could be useful for sustainable management of natural resources and thus minimize future hydrologic and environmental impacts. In this study, potential impacts from three wide-ranging scenarios are compared to current conditions of a region in terms of a set of processes that are modeled in a geographic information system (GIS). Alternative futures landscape analysis involves 1) describing development patterns and significant human and natural processes that affect a particular geographic area of concern; 2) constructing GIS models to simulate these processes and patterns; 3) creating changes in the landscape by forecasting and by design; 4) and evaluating how the changes affect pattern and process using models . This study presents an integrated approach to identify areas with potential water quality problems as a result of land cover change projected by stakeholders within the basin. Landscape metrics describing spatial composition and spatial configuration were computed using the Analytical Tools Interface for Landscape Assessments (ATtILA) tool. The landscape metrics generated from ATtILA were used in conjunction with the Automated Geospatial Watershed Assessment (AGWA) tool to examine the contribution of land use/land cover to water and sediment yield and identify subwatersheds within the Willamette River basin that would be most affected in the year 2050 relative to three possible future scenarios which include inherent differences related to conservation, planning, and open development.

Technical Abstract: The traditional definition of security has been broadened to include environmental threats resulting from resource degradation and scarcity related to anthropogenic development. This paper examines the use of landscape indicators to identify the susceptibility of the U.S. state of Oregon to resource and water-related conflict. It then applies hydrological process models to examine the consequences and benefits of three plausible build-out options relative to their impact on the availability and quality of water resources of the Willamette River basin. The hydrological outputs were estimated for a baseline year circa 1990 and projected to the year 2050; they were provided as an alternative futures analysis for integrating a scientific framework into decision-making processes for determining present and future policy relative to land use, management, and development.