Abstract
Accurate field data are required to predict elevated runoff and sediment
transport to aid post-fire planning. This is especially significant at
the small catchment scale, where these runoff processes occur
disproportionately, occurring at a higher magnitude and higher
frequency. Sources of elevated runoff include soil hydrophobicity,
in-channel sediment loading through dry ravel, extensive rill networks,
and exposed bare soil. Recovery of these processes are related to
vegetation conditions before, during, and after fire. This can be
quantified using satellite-based vegetation indices to understand the
recovery of the burned area and resulting hydrologic response. The main
objective was to demonstrate potential for ECOsystem Spaceborne Thermal
Radiometer Experiment on Space Station (ECOSTRESS) evaporation
measurements in post-fire hydrology by linking to hydrologic signatures
(flashiness index and runoff-ratio) to highlight changes and improve
vegetation assessments after fire. A case study of the 2018 Holy Fire is
presented using a control catchment and a burned catchment. Results show
that areas containing higher proportions of montane hardwood and montane
hardwood conifers burned at high soil burn severity, a result of the
normal to moderately dry period (2012-2016, 2018) that decreased annual
evapotranspiration and increased water stress leading up to fire. For
1-year post-fire, ECOSTRESS measured the highest variation between
burned and control during the peak dry months (3 to 4 mm/day), which
explained the comparatively higher dry-season flows observed for the
burned catchment. Summer field visit also showed vegetation regrowth
that consisted of mostly annual grasses following a moderately wet year.
Preliminary results were adequate; however, not enough time has passed
for the system to fully recover, and thus, we present a Google Earth
Engine application to help track recovery.