1. Prediction of Channel Response Areas due to Wildfire Disturbance using GIS and TauDEM
Karen Williams
GIS in Water Resources

2. Project Objective
Use spatial distribution of channel, network, and landscape characteristics to predict channel areas most likely to respond to wildfire disturbance
Stream power
Channel slope
Hillslope gradient
Burn severity
Stream order
Land cover

3. Geomorphic Disturbance and Response
Disturbance regime:
Landscape processes that influence the “supply, storage, and transport of water, sediment, and wood” (Benda et al, 1998)
Examples: wildfire, mass wasting, timber harvest
Response to disturbance varies with channel type, basin morphometry, land cover and use

4. Dutch Creek

5. Project Watershed: Dutch Creek
Basin area = 28 sq.mi.
Drains southwest to North Fork Flathead River

7. Project data 10 m. cell size elevation raster data Stream vector data
Land cover raster data
Burn severity raster data
All obtained from Glacier NP GIS person

8. Methods Stream network (demnet) - TauDEM
Compared to streams layer from GNP
Created network includes more low order channels
Stream order raster (demord) - TauDEM
Channel slope – TauDEM
Slope between links reported in demnet
Classify slopes by Montgomery and Buffington (1997)
<2% = response reach
2-4% = transport reach
> 4% = source reach
Hillslope gradient – DEM raster toTIN
Burn severity and land cover - GNP

9. Comparison of TauDEM and Glacier NP stream vector data
Glacier NP stream vector data created from 1:24,000 maps, digital orthoquads and aerial photos
TauDEM created more low order streams
Low order, ephemeral channels are conduits for sediment and wood delivery

10. Land cover raster data Mostly coniferous forest
High severity burn in riparian coniferous forest increases frequency and extent of woody debris delivered to channel

11. Hillslope Gradient and Channel Slope
Much of watershed is moderate slope
Areas of steep hillslopes are more likely to be subject to mass wasting

12. Fire History: Anaconda 1999, Moose 2001, WolfGun 2003

13. 2001

14. 2003

15. Methods Stream power, Channel slope, S Discharge, Q
The ability of channel to do work, power per unit length
Channel slope, S
Option in TauDEM: Define a feature class of nodes at which slope will be calculated
Discharge, Q
Assume the two-yr recurrence interval flood approximates the channel forming (dominant discharge) Q2
For this region, Q2 = A^.918 * P^1.33
A = area in sq.mi; P = mean annual precip., in.
Determine Q2 at each node

16. Mean annual precipitation polygon
5 precipitation zones in watershed
Contributing area at each node apportioned by precipitation zone

17. Stream power and channel slope
Areas of high stream power not necessarily correlated with channel slope
Not enough nodes to be conclusive

18. Stream power at nodes and stream order
Some nodes of high stream power occur where low order and higher order channels confluence

19. Based on spatial distribution of basin and channel characteristics, the identified channel areas of severe burn, moderate hillslope gradient, and moderate to high stream power may exhibit a response

20. Thanks to Glacier NP Dave Tarboton
Questions?
Thanks to Glacier NP Dave Tarboton