Title: Metadata for the primary data produced and used in the dissertation titled, Spatial and temporal channel changes across the watershed scale following wildfire and floods. 

Primary investigator: Peter A. Nelson, Department of Civil and Environmental Engineering, Colorado State University, 1372 Campus Delivery, Fort Collins, CO 80523-1372. Phone: +1 (970) 491-5247. Email: peter.nelson@colostate.edu

Co-investigator: Daniel J. Brogan, Department of Civil and Environmental Engineering, Colorado State University, 1372 Campus Delivery, Fort Collins, CO 80523-1372.

Contact: Peter A. Nelson (peter.nelson@colostate.edu)

General description: Data provided include digital elevation models (DEMs), DEM of Differences (DoD), rainfall depth and maximum 30-minute intensity (MI30), and morphometric data for analyses on two burned watersheds, Skin Gulch (SG) and Hill Gulch (HG), just west of Fort Collins, Colorado, U.S.A. The DEMs and DoDs cover the channel networks, while the precipitation data cover the entire watersheds. For more detailed information about the methodology in creating these data and how the data were used please refer to Brogan (2018).

Abstract for research of these data: Post-wildfire landscapes are highly susceptible to rapid geomorphic changes at both the hillslope and watershed scales due to the increases in infiltration-excess overland flow, hillslope and channel erosion, and downstream deposition. While there have been numerous studies of these processes at the hillslope scale, relatively few studies have documented larger-scale post-fire geomorphic changes over time. In this study we used five airborne laser scanning (ALS) datasets collected over four years to quantify valley bottom changes in two ~15 km^2 watersheds, Skin Gulch and Hill Gulch, after the June 2012 High Park fire in northern Colorado and followed by a large mesoscale flood 15 months later. The objectives were to: 1) quantify spatial and temporal patterns of erosion and deposition throughout the channel network following the wildfire and subsequent flooding; and 2) investigate the extent to which these changes can be related to precipitation amounts and intensities, burn severity, and valley and basin morphology. Geomorphic changes were quantified using a DEMs of difference (DoD) approach for the channel network segmented into 50-m lengths. The DoDs show net sediment accumulation after the wildfire in the valley bottoms in both watersheds, with the greatest accumulation after summer thunderstorms in the first two years after burning in areas with wider and flatter valley bottoms. In contrast, the mesoscale flood caused large amounts of net erosion, with the greatest erosion in those areas with the greatest post-fire deposition. Volume changes for the different time periods were low but significantly correlated to, in order of highest correlation, contributing area, channel width, percent burned at high and/or moderate severity, channel slope, confinement ratio, maximum 30-minute rainfall, and total rainfall. These results suggest that morphometric characteristics, when combined with burn severity and a specified storm, can indicate the relative likelihood and locations for post-fire erosion and deposition. This information can help assess downstream risks and prioritize areas for post-fire hillslope rehabilitation treatments.

License information: CC BY 4.0

Recommended data citation: Brogan, Daniel J. and Peter A. Nelson (2019). Dataset associated with "Spatial and temporal patterns of sediment storage and erosion following a wildfire and extreme flood." Colorado State University. Libraries. http://dx.doi.org/10.25675/10217/193080

Format of data files: DEM data are provided as GeoTIFF (.tif) files with associated .tfw, .ovr., and .xml files. Delineated valley bottom segments are provided as ESRI shapefiles (.shp, and associated files). Rainfall and MI30 data are provided as GeoTIFF (.tif) files. Summary data of all variables for each valley segment are provided as .csv files.

Dates: DEM data were produced from airborne laser scanning data collected during five different time periods. These time periods were primarily during the months of October 2012, July 2013, October 2013, August 2014, and June 2015. The precipitation data were collected continuously from October 2012 through November 2015. 

Location: The approximate location of the Skin Gulch outlet is at 40.6824 degrees north and 105.3896 degrees west, and the approximate location of the Hill Gulch outlet is at 40.6859 degrees north and 105.3039 degrees west.

File Information: 
Digital Elevation Model (DEM) data use the following naming convention: watershed_yyyymm_DEM.xxx, where 'watershed' is 'HG' for Hill Gulch and 'SG' for Skin Gulch, yyyymm is the year and month of the data collection, and .xxx is the file extension (e.g., .tif). Elevations in the DEM are in meters.
DEM of Difference (DoD) data use the following naming convention: watershed_yyyymm1-yyyymm2_DOD.xxx, where 'watershed' is 'HG' for Hill Gulch and 'SG' for Skin Gulch, yyyymm1 is the year and month of the 'before' DEM, yyyymm2 is the year and month of the 'after' DEM, and .xxx is the file extension (e.g., .tif). Elevation differences are in meters.
Valley bottom segment shapefiles use the following naming convention: watershed_ValleyBottomSegments.xxx, where 'watershed' is 'HG' for Hill Gulch and 'SG' for Skin Gulch, and .xxx is the file extension (e.g., shp).
Cumulative rainfall total raster files use the following naming convention: Rainfall_yyyymmdd_to_yyyymmdd.tif, where yyyymmdd represent the beginning and ending dates of the record. Data are in mm.
Maximum 30-minute rainfall intensity raster files use the following naming convention: MI30_yyyymmdd_to_yyyymmdd.tif, where where yyyymmdd represent the beginning and ending dates of the record. Data are in mm/h.
Summary data for each valley bottom segment use the following naming convention: watershed_MasterList_yyyymm1_to_yyyymm2.csv, where 'watershed' is 'HG' for Hill Gulch and 'SG' for Skin Gulch, yyyymm1 is the year and month of the 'before' DEM, yyyymm2 is the year and month of the 'after' DEM.

Variable information: 
For the 'MasterList' .csv files, these are the column headings:
FID: FID associated with the valley bottom segment shapefiles
Deposition: Deposition from the DoD within the segment (m3); positive values indicate deposition.
Erosion: Erosion from the DoD within the segment (m3); negative values indicate erosion.
Net_volume_change: net volume change (deposition - erosion) (m3), positive indicates net deposition, negative indicates net erosion.
Slope: average slope of the segment.
DeltaSlope_w3: topographic curvature calculated from the slope of a linear regression where the channel slope of the segment and the two upstream segments were plotted against the distance upstream. (1/m)
DeltaSlope_w5: topographic curvature calculated from the slope of a linear regression where the channel slope of the segment and the four upstream segments were plotted against the distance upstream. (1/m)
DeltaSlope_w10: topographic curvature calculated from the slope of a linear regression where the channel slope of the segment and the nine upstream segments were plotted against the distance upstream. (1/m)
Segment_length: average length of the segment (m)
Contributing_area: contributing watershed area to that segment (km2)
Valley_width: average valley width in the segment (m)
DeltaWidths_w3: valley constriction or expansion calculated from the slope of a linear regression where the valley width of the segment and the two upstream segments were plotted against the distance upstream.
DeltaWidths_w5: valley constriction or expansion calculated from the slope of a linear regression where the valley width of the segment and the four upstream segments were plotted against the distance upstream.
DeltaWidths_w10: valley constriction or expansion calculated from the slope of a linear regression where the valley width of the segment and the nine upstream segments were plotted against the distance upstream.
Slope_width: ratio of segment slope to segment valley width (1/m)
DeltaSlopeWidths_w3: change in slope-width ratio from the slope of a linear regression where the slope-width ratio of the segment and the two upstream segments were plotted against the distance upstream. (1/m2)
DeltaSlopeWidths_w5: change in slope-width ratio from the slope of a linear regression where the slope-width ratio of the segment and the four upstream segments were plotted against the distance upstream. (1/m2)
DeltaSlopeWidths_w10: change in slope-width ratio from the slope of a linear regression where the slope-width ratio of the segment and the nine upstream segments were plotted against the distance upstream. (1/m2)
Channel_width: Channel width estimated with the relationship w_c = 1.24*A^0.435, where A is the drainage area in km2 and wc is the channel width in m.
Confinement_ratio: ratio of valley width to channel width
Precipitation_depth: total precipitation in the segment computed from radar data over the time period indicated in the filename (mm)
Max_30-min_intensity: maximum 30-minute precipitation intensity in the segment computed from radar data over the time period indicated in the filename (mm/h)
Moderate_burn_severity: fraction of the contributing area to the segment classified as moderate burn severity
High_burn_severity: fraction of the contributing area to the segment classified as high burn severity
Moderate-high_burn_severity: fraction of the contributing area to the segment classified as moderate or high burn severity.

Date dataset was last modified: 26-12-2018


Keywords: Wildfire, floods, erosion, deposition, sediment availability, high-resolution topography


Funding information: This work was supported financially by the National Science Foundation (EF-1250205, EF-1339928, and EAR-1419223), U.S. Department of Agriculture National Institute of Food and Agriculture Hatch project (1003276), the Arapaho-Roosevelt National Forest, and the USDA Forest Service National Stream and Aquatic Ecology Center. Airborne laser scanning was provided by the National Ecological Observatory Network, a project sponsored by the National Science Foundation. This material is based in part upon work supported by the National Science Foundation under Grant No. DBI-0752017.

References:
Brogan, D.J. (2018), Spatial and temporal channel changes across the watershed scale following wildfire and floods, Dissertation, Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado, 248 pp.




