Authors: Jerry Davis*, San Francisco State University, Leonhard Blesius, Department of Geography & Environment, San Francisco State University, Michelle Slocombe, Environmental Scientist, CalRecycle, Mike Vasey, SF Bay National Estuarine Research Reserve
Topics: Environmental Science, Physical Geography, Geomorphology
Keywords: geomorphology, hydrology, biogeography, microclimatology, soils, meadows, wetlands, restoration
Session Type: Paper
Start / End Time: 3:20 PM / 5:00 PM
Room: Astor Ballroom I, Astor, 2nd Floor
Presentation File: No File Uploaded
Montane meadows in the Sierra Nevada range experienced a long history of degradation from railroad timber extraction and channel headcuts, and efforts to restore wetland properties have reestablished vegetation and soil characteristics that interact closely with meadow hydrogeomorphology. The impacts of wetland degradation on carbon and snowmelt storage are major concerns related to climate change, and restoration efforts offer benefits in carbon sequestration and water resources. Especially in restored meadows with relatively small drainage basins, channel patterns exhibit step-pool characteristics in longitudinal profile and altered sinuosity reflecting the influence of willow copses, hillslope margins and boulders. Field methods have included GPS + level survey of channel development and low-altitude remote sensing of vegetation and channel scour features. Imaging technology developed for precision agriculture was deployed using a small unpiloted quadcopter-mounted sensor capturing narrow bands of 465-485, 550-570, 663-673, 820-860 (NIR), and 712-722 (red-edge) nm at a resolution of 5.6 cm, detecting fine patterns of vegetation reflecting ephemeral flow and hydrologic connection to the restored piezometric surface. Normalized difference vegetation indices (NDVI) incorporating red edge and near infrared was used to detect hydrophilic root-mat producing vegetation species such as Carex utriculata and C. nebrascensis. Evidence of degraded root mats dating from pre-impact wetland conditions help to reconstruct the wetland system that predated the impact of railroads on channel incision. Understanding controls and tendencies of channel development related to biogeomorphic controls as well as their changes over short timeframes help to guide meadow and other wetland restoration efforts.