The Role of Remotely Sensed Data in Future Scenario Analyses at a Regional Scale - Fluvial Remote Sensing for Science and Management - page 274

were reported in Lattin and Peniston, 1999 and Hulse
et al., 2002.
In areas of extensive human development and land
conversion, additional data sources were used to refine
satellite data (e.g., tax lot data, 1990 U.S. Census
data, road data from transportation agencies, aerial
photographs, USGS topographic quadrangle maps).
Rivers, streams, lakes, and wetlands were mapped using
TM and U.S. Census data, USGS maps, digital elevation
models, aerial photographs, and ground truthing.
Maps of historical channels and riparian forests of the
mainstem Willamette River were created from General
Land Office survey maps from 1850-1860 and US Army
Corps

Opportunity Areas, were mapped and then reviewed by
a series of groups regarding the political plausibility of
conserving or restoring them to the indicated vegetation
types. The three alternative 2050 futures, as well as the
1850 past conditions, were then evaluated by an array of
computerised evaluation models.
Maps of several natural resources - forest type, riparian
forest, surface water - were used as ecological response
measures in the assessment of alternative scenarios. In
addition, the effects of each future on major terrestrial and
aquatic communities were modeled based on observed
relationships between habitat and community compo-
sition or species abundance in the WRB (Schumaker
et al., 2004, Van Sickle et al., 2004). Models were used to
project wildlife diversity, native fish richness, cutthroat
trout abundance, fish habitat suitability indices, and EPT
richness (numbers of taxa of Ephemeroptera, Plecoptera
and Trichoptera; orders of aquatic macroinvertebrates
that require high water quality). Models of future water
availability were based on designated water availability
basins and projected water use by different water use
sectors (Dole and Niemi, 2004). Future environmental
changes that are recognised but not analysed in this study
of future scenarios include climate change, groundwater
withdrawal, or new toxic substances in the environ-
ment. Past effects on these three phenomena are inherent
in the observed relationships between land cover, land
use, and biotic responses, but future changes in these
environmental parameters may not be reflected in our
analyses.

of Engineer river maps from 1895 and 1932

(Gregory et al., 2002d, 2002g, Oetter et al., 2004).

12.2.2 Useof remotelysenseddata inthe larger
alternative futuresproject

Simply put, the map that resulted from the methods
described above was used to depict existing conditions
ca. 1990 for the Willamette River basin. This depic-
tion became a baseline reference for comparing changes
from the past to the present, and from the present to
three alternative futures. These depictions were used to
better understand and anticipate trajectories of change
in human occupancy and natural resource condition
from ca. 1850 to ca. 2050. In the Willamette River basin
project, all three major purposes of scenario develop-
ment identified by Henrichs et al. (2010) were served.
During a 30-month period, we worked with lay and pro-
fessional citizen groups to create, map, and refine a set
of value-based assumptions about future policy in three
scenarios concerning land and water use. The Plan Trend
2050 scenario represented the expected future landscape
in 2050 if current policies are implemented as written
and recent trends continue. Development 2050 reflected
a loosening of current policies, to allow freer rein to
market forces across all components of the landscape,
but still within the range of what citizen stakeholders
considered plausible. Conservation 2050 placed greater
emphasis on ecosystem protection and restoration, still
reflecting a plausible balance among ecological, social,
and economic considerations as defined by the stake-
holders. For the Conservation scenario, natural resource
managers and scientists provided estimates for the area of
key habitats required to sustain, in perpetuity, the array
of dependent species. Spatially explicit analyses identified
locations biophysically suited to meet the area targets.
These locations, titled the Conservation and Restoration

12.3 Land use/land cover changes
since 1850

Land cover in the Willamette basin changed markedly
from the time of settlement to the present, as illustrated
by changes in mapped land cover from 1850 and remotely
sensed land cover from 1990. During this 140-year period
of EuroAmerican settlement, lowlands of the WRB were
settled and converted to agricultural and urban land uses.
Historically 50% of the lowlands were forested, and by
1990 forested land in the lowlands had been reduced
to approximately 30% (Gregory et al., 2002a, 2002e).
The uplands were almost completely covered with forests
(98%), which largely remain the case (96%). Older forests
(conifers > 80 yr) once covered 60% of the WRB, but by
1990 these older forests occupied only 20% of the basin.
The land cover of the WRB changed markedly from
1850 to 1990, and riparian forests changed to an even