Data collection and preparation
LiDAR terrain data were used to define flow paths and delineate the
topography of roads in the study site. The LiDAR remote sensing data of
Lake Tahoe were collected by Watershed Sciences, Inc. (WSI) in August
2010. The survey used two Leica ALS50 Phase II laser systems mounted in
a Cessna Caravan 208B. The average first-return density of the delivered
dataset was 11.82 points m-2 and the average ground
return density was 2.26 points m-2. A raster elevation
data set with a resolution of 0.5 m was created based on the ground
return points from the LiDAR flight (Figure 1). We estimated soil burn
severity using the differenced Normalized Burn Ratio (dNBR) from Landsat
ETM 7 images from information before and after the fire to generate a
Burned Area Reflectance Classification (BARC) layer (Parsons, Robichaud,
Lewis, Napper & Clark, 2010). The BARC data were classified following
Parsons et al. (2010) to estimate soil burn severity (Table 1).
Michigan Technological Research Institute (MTRI) together with US Forest
Service and NASA developed a rapid response tool to provide a 30-m
digital elevation model, soil and land cover layers, and the linkage
files necessary to run a spatial WEPP (Water Erosion Prediction Project)
simulation of post-fire erosion
(http://geodjango.mtri.org/geowepp/; Miller, Elliot, Billmire,
Robichaud, & Endsley, 2016). We uploaded the BARC raster map onto the
MTRI main page, and then downloaded soil and land use files formatted
for GeoWEPP (Miller, Billmire & Banach, 2015) for the study site. The
LANDFIRE Existing Vegetation Type (EVT) data downloaded from the Miller
et al. (2015) server were adopted as the prefire land cover. Soil and
land use data were provided as 30-m resolution raster files and stored
in an ASCII format, including both pre-fire and post-fire conditions.
The post-fire soil properties modification was achieved following the
instructions described by Elliot and Hall (2010). We were then able to
run the WEPP model spatially under different soil and land use types
describing both pre-fire and post-fire conditions.