2021 Virtual Undergraduate Research Symposium

2021 Virtual Undergraduate Research Symposium

Correlation of Precipitation and Rockfall using Remote Sensing Data

Correlation of Precipitation and Rockfall using Remote Sensing Data

PROJECT NUMBER: 54 | AUTHOR: Samantha Gillaspie​, Geology and Geological Engineering

MENTOR: Gabriel Walton, Geology and Geological Engineering

ABSTRACT

Rockfall in Colorado costs the Colorado Department of Transportation (CDOT) millions of dollars a year. Rockfall in Glenwood Canyon is a large contributor to this issue. Despite multiple precautions such as the removal of unstable rocks and rockfall fences in place, Interstate 70 is still closed on a semi-regular basis due to damages to the road caused by rockfall.
Biweekly point cloud data collected and processed by Heather Schovanec and weather data collected by NOAA near the study site was used to analyze the correlation between precipitation occurrence and rockfall in the area in question. Maximum precipitation in a day within each monitoring interval, sum of the amount of precipitation in each interval, and the number of days with precipitation in each interval were compared to the total volume of rockfall within each interval. Because of the significant variability in precipitation throughout the year, different time frames were considered using the criteria above. Time frames examined include seasons and three- month division throughout the year. The division of seasons showed little correlation for much of the year. Summer did show significant correlation, but the three-month time frames showed stronger correlations throughout. Number of days with precipitation and the sum of precipitation within a given interval were the most significant factors overall throughout the year. Intervals surrounding the middle and end of the year seemed to have stronger correlations between precipitation variables and rockfall.

PRESENTATION

AUTHOR BIOGRAPHY

Samantha is a junior at mines studying geology and geological engineering doing research in the same department. She is interested in studying geologic hazards and how to better predict and adapt to these challenges. She hopes to do more research in regards to this area in the future.

11 Comments

  1. What is the “r” stand for in figure 2 and 3? What is equation of this ratio?
    How do you measure rockfall in millimeters? This is not liquid. Can you explain this?
    What is Pcpn? Precipitation? This is unclear! Write the entire word or define what it is.

    • Hi Shaked,
      That was an old, incorrect draft. It’s been updated, let me know what you think of this one!
      Thanks!

      • I know that this is based off a study area in the Glenwood springs area but do you believe that the same factors that affect rockfall in the study area could also be factors in rockfall throughout the state?

        • Hi Jimmy,
          That’s a difficult question. While this may correlate to similar slopes and these factors likely have some correlation throughout the state, I would not claim that this is an accurate model for rockfall throughout the state.

  2. Does summer experience the highest precipitation value with respect to other seasons? If so, what types of precipitation influence rock fall more? It also seems that more data points would be needed to extract a better linear regression of maximum precipitation vs. rockfall graphs.

    • Hi Chad,
      Overall, summer generally saw the most precipitation, and rain was more influential than snow. The two-week plus scanning intervals for the past few years did limit the amount of data for each timeframe studied, so it would be nice to have more data to support or disprove this hypothesis.

  3. what is worse for rockslides – the rate at which rain falls or the total amount?

  4. Very interesting result. It would be interesting to see how/if snowfall has a larger or smaller impact compared to rainfall.

  5. Sam,

    Why do you think the summer months had the greatest correlation?

  6. Hi Sam! Do you think that the hotter temperatures in the summer have anything to do with it having the greatest correlation? For example, in the winter, the ground becomes harder, so perhaps rockfall decreases because the rocks are more “stuck together,” whereas, in the summertime, the rocks and ground are “looser,” increasing the chances that precipitation may affect rockfalls.

  7. Hi Sam,
    The results from this are intriguing as we learn a lot of rock fractures occur during freeze and thaw. Because of this, why do you think the Spring has a lower correlation when it is one of the seasons with the most freeze and thaw occurring.

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