1. Steve Raber, QSI Senior Program Manager
West Salt Creek
Landslide
GeCo in the Rockies Conference | September 24, 2014
Matt Morgan, Jon White, F. Scot Fitzgerald and Karen Berry , Colorado Geological Survey

2. •Massive landslide on May 25th, 2014
•Lower escarpment of the Grand Mesa
•Near Collbran, CO … about 40 miles east of here (Grand Junction) …
•3 men killed …
•Current concerns:
–potential pond failure/flood inundation
–continued movement
–proximity to active well heads
•High density LiDAR supported analyses

4. Landslide
Collbran
Grand Junction

5. TIMELINE
West Salt Creek Landslide

6. Sunday, May 25, 2014
Morning
•Precursor landslide -- east side of West Salt Creek (noted by landowner)
•Disruption of irrigation ditch
•Second precursor slide -- west side of creek
•Eyewitness noted moving ground / crashing/toppling trees on upper valley floor
Late afternoon
•Inspection by landowner’s son and county public works employees
•5:45 pm … 3 landslide pulses within 3 minutes

7. West
East
3 well heads
Courtesy of Colorado Geological Survey

8. 660 ft
2.8 mi
1,700 ft
Courtesy of Colorado Geological Survey

9. Interagency Response
•Mesa County (Sheriff’s office, Emergency Mgmt., Public Works, other agencies)
•FEMA
•Colorado Office of Emergency Management
•U.S. Forest Service
•U.S. Geological Survey
•National Geospatial- Intelligence Agency (NGA)
•Colorado School of Mines (CSM); Colorado Geological Survey (CGS)
•U.S. Army Corp of Engineers (USACE)
•USDA National Resources Conservation Service (NRCS)
•NOAA
•Colorado Mesa University
•Div. of Water Res./Dam Safety Program
•Colo. Water Cons. Board
•Town of Collbran

10. Following Week
•Monday, May 26 – Memorial Day
•Monitoring tools installed (USFS, USGS, Mesa County)
–Unmanned Aerial Systems (UAS) – image acquisition
•Inundation/flood modeling (USGS, USACE, others)
•LiDAR coverage (CGS/Colorado State)
–Quantum Spatial (QSI) – Acquisition partner
•3D modeling (CGS, CSM)
•Slope stability analyses (CSM)
•Mapping (USGS, CGS)

11. LiDAR Discussions (Following Week cont.)
•QSI - CGS discuss rapid response for LiDAR acquisition
•LiDAR study area determined
•Response time determined
•Mobilization planning
•Proposal dev’t / Contracting
•CGS emergency access to funds
Courtesy of Colorado Geological Survey

12. CGS Need for LiDAR
•Critical: snapshot of slide immediately following event, for baseline elevation and change-detection analyses
•Modeling of slide for potential inundation of Collbran
•Stability analyses of upper rotated block
•Additional landslide hazard mapping around slide area
•Calculation of slide volume, areas of excavation and deposition
•Elevation data for placement of roadways, canals, and other engineered features

13. LIDAR ACQUISITION & PROCESSING
West Salt Creek Landslide

14. Area of Interest
Debated Options
Final AOI
48,118 acres

15. Acquisition Plan
•Mobilize aircraft from nearby project site (Partenavia P68)
•Start collection on Sunday, June 1
•Simultaneously acquire control points
•Coordinate with onsite incident command (OIC)
–Mesa County Sherriff
–Temporary flight restriction (TFR)

16. LiDAR Specs
•48,118 acres
•12 hrs flying time
•1400m (~4600’) AGL
•10,200’ terrain elevation
•ALS70 Sensor
•O2 required for flight crew
LiDAR Specifications Summary
Multi-Swath Pulse Density
≥ 8 pulses/m2
Scan Angle
≤30o (+/-15o from Nadir)
Returns Collected Per Laser Pulse
Up to 4
Intensity Range
1-255
Swath Overlap
50% side-lap (100% overlap)
GPS PDOP During Acquisition
≤3.0
GPS Satellite Constellation
≥6
Maximum GPS Baseline
13 nautical miles
Accuracyz (1.96 ), slope <20o
< 20 cm
Vertical Accuracy (), slope <20o
≤ 9 cm
Horizontal Accuracy ()
≤ 30 cm

17. Deliverables
•LiDAR
–Point Cloud
–All returns, Las 1.2 format
–Point files: X,Y,Z, Return Intensity, Return Number, Point Classification (ground, default), Scan Angle, GPS Time
•Surface Models
–Highest Hit DEM, 1m resolution, ESRI Grid format
–Intensity Images, 0.5m resolution, GeoTiff format
•Vectors
–Survey Boundary, shapefile format
–Tiling delineations, shapefile format
•Reporting
–Methods, Results, Accuracy Assessments, pdf and Word format
–Ground Check Points, shapefile format
–FGDC-compliant Metadata

18. Delivery Schedule
•NTP: Fri 5/30/14
•Acquisition
–Start: Sun 6/1/14
–80% complete: Mon 6/2/14
–100% complete: Tues 6/3/14
•Processing
–Start: Wed 6/4/14
–Final deliverables: Mon 6/16/14
•~18 Days from NTP to delivery!

19. PRELIMINARY FINDINGS
West Salt Creek Landslide

20. LiDAR Surface Model

21. LiDAR Bare Earth Surface

28. General
•Classified as an extremely rapid rock/debris avalanche and debris flow
•Precipitation was slightly above average (morning of 5/25: 1.5" in 3.5 hours)
•Moved 2.8 miles, down 2200 vertical feet, from about 9,600’ to 7,400’ elev.
–Length 7 times the vertical height
•Flows of disaggregated and pulverized rock occurred as cascading stacked pulses (3), mostly constrained by West Salt Creek valley
•Landslide deposit at toe was only slightly damp with steep slope at edge (~40 degrees)

29. General (cont.)
•Debris/rock avalanche covered 599 acres (0.95 square miles)
•3 fatalities; remains not yet found
•Pick-up truck and 4-wheeler also missing
•At assumed truck location at end of road, slide is 1,900’ wide and debris deposit up to 125’ thick
•Current ground movements very small, mostly in terms of vertical consolidation and settlement (F. Kochevar, Mesa Co.)

30. West Salt Creek
Oxy Hawkins Ranch
#14-4A
#14-3A
#11-13C
Assumed truck location
Courtesy of Colorado Geological Survey

31. ~2,900 ft
~450 ft
Cross sections generated from 4m IfSAR DEM provided by FEMA and post- landslide LiDAR
Area of
evacuation

32. Tire tracks of missing truck

33. Geologic
•Eastern portion of ancient landslide failed in recent past (1984, according to Hawkins family)
•Upper scarp mapped in regional landslide study by CGS (Soule, 1988)
•The May 2014 landslide occurred at same ancient scarp of a geologically recent landslide complex
•Full geologic characterization conducted by CGS, USGS, and Colorado Mesa University

34. Mechanisms of Failure
•Trigger: 2,700’ wide rotational block failure
•Caused rock avalanches and debris flows
•Block failed along pre-existing ancient scarp
•Rotational failure and back-tilting of upper block created depression below main scarp of landslide
•Eyewitness: entire landslide was in-place within a 15-minute time frame. Seismic wave indicated major block failures within 3 min.

35. Slide Morphology
•Assessed using:
–High resolution aerial photography (UAS)
•County collected photography during rescue and recovery period (when slide considered unsafe)
•Now available on GoogleEarth (3 months after slide)
–High density LiDAR hill-shade
–Locations of red soil remnants -- reveals some sense of sequence of deposits

36. Photogrammetry
Courtesy of Mesa County Sheriff’s office
100s of UAS images

37. Long-Term Threats/Concerns
•Stability of upper rotated block
•Reactivation and retrogressive failures above existing head scarp
•Threat of subsequent mud/debris flows
–Breach and rapid outlet of ponded water
–Mini-tsunamis
•Inundation of Salt Creek and flood threat downstream
•Spread of landslide toe to Salt Creek
•Burial and shearing of Oxy well heads

38. Well heads
Tanks and other infra-
structure relocated here
Diversion berms and other earthwork to direct flows away from well pad

39. CURRENT ACTIVITY
West Salt Creek Landslide

40. Pond Monitoring
•Water flowed into depression due to spring run-off, at high rate
–up to 15 to 30 cfs; current rate ~2-4 cfs
–Pond: ~1,500 ac-ft (65,000,000 ft3)
•Level stopped rising at end of June
•Seeping occurring from base of upper block and small ponds appearing in center of slide and below east ridgeline
•Still no water seeping from landslide toe as of September 5
West view (8/21/14)

41. Future publications
•CGS completing preliminary report of the landslide fall 2014
•USGS to complete final paper and detailed map of landslide in future publication

42. QUANTUM SPATIAL
Geospatial Services

43. The Power of 3

44. Data Information Understanding
LANDSLIDES

45. Landslide Experience
•Oso, WA landslide LiDAR response (2014) – WA DOT; pre- and post-slide data
•Oregon Department of Geology And Mineral Industries (DoGAMI) testing of entire Vernonia 7.5’ quad (west of Portland, OR)
•California power company – identification of landslides in 32 mile corridor (Lake Tahoe area) … for remediation purposes
•Additional pilot studies and smaller projects

46. Methods/Tools Development
•Landslide Support (what we do)
–Detection and risk (semi-automated methods)
–Rapid response (data acquisition)
–Detailed analytics
–Impact analyses
–Monitoring (LiDAR)
•Detection methods
–Use of open source GIS, Python, C++, and Java scripting
–Pattern recognition algorithm developed by Chang/Lin
–Extrapolate conditions based on modeling of small training sites
–Polygon labeling and attribution – landslide metrics
•Future: development of terrain failure hazard maps

47. Landslide Analytics
•Tool generates multiple layers based on topography; highlights surface feature aberrations
–ID sensitive areas previously unknown, unmapped, unmanaged
–IDs areas of high, medium and low risk terrain failure
–Determine areas of concern, reveal new potential risks, and help experts focus resources in vulnerable areas

48. Polygons attributed with susceptibility information

49. Field Tested, Geologist Approved
QSI has achieved 95% accuracy for landslide detection
Quantum Spatial automated result
DoGAMI delineation
Field Survey

50. Case Study
Quantum Spatial automated Landslide delineation
Transmission Line
California power company – landslide detection for mitigation/remediation

51. Questions
sraber@quantumspatial.com
Acknowledgements:
Quantum Spatial greatly appreciates the support of Matthew Morgan, Senior Research Geologist at the Colorado School of Mines (CSM), Colorado Geological Survey (CGS), for a large portion of the content of this presentation.