HILLSLOPE STABILITY. Focus in the Westfork Area of Washington County, Arkansas. Environmental Geology Dr. Paul Lowrey

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1 Environmental Geology Dr. Paul Lowrey Team Members Christine Gossett Jennifer Lane Lauren Morrison Nicole Sage Focus in the Westfork Area of Washington County, Arkansas HILLSLOPE STABILITY

2 INTRODUCTION

THE IMPORTANCE OF DETERMINING HILLSLOPE STABILITY Identification of areas in danger of potential slope failure provides the opportunity to minimize danger to humans and their environment through:

3 THE IMPORTANCE OF DETERMINING HILLSLOPE STABILITY Identification of areas in danger of potential slope failure provides the opportunity to minimize danger to humans and their environment through: Employing appropriate mitigation techniques to delay failure Restricting human access to hazardous areas Slope Failure = Mass Wasting = Landslide (engineering term) (geological term) (common term) INTRODUCTION

4 PROJECT OVERVIEW

5 WHAT THE TEAM DID IN A NUTSHELL Met to define, plan and produce project proposal Learned to use GIS Technology to identify potential slope failure sites in Washington County Produced a map of potential sites; narrowed focus to area around Westfork, Arkansas Undertook research to better understand how to recognize conditions that indicate potential slope failure Made field trips to document presence of identified factors Drew conclusions about the likelihood of imminent failure Designed products for dissemination of results OVERVIEW

6 COMMUNITY

7 Community Served: The location of sites investigated were near the population center of Westfork, Arkansas. However, the actual community served includes all who travel through that area on Highway 71 or Interstate 540. Service: Field-checking of sites composed of weak bedrock on steep slopes that were located within 50 feet of the highway. Verified slope steepness, type and orientation of rock present Checked for evidence of recent slides, creep and/or slump, and the presence of a large amount of debris. Looked for other conditions that could affect potential failure such as the presence and flow of water, lack of vegetation, and undercutting of slopes Community Contacts: Arkansas Highway and Transportation Department COMMUNITY

8 Environmental Geology CURRICULUM OBJECTIVES Understand how the scientific method is applied to environmental issues Relate geological principles to environmental issues Recognize the relationship between humans and the environment, particularly the effects of population growth on natural systems Be aware of the effects of natural hazards on humans and the environment Demonstrate the ability to utilize Global Positioning Systems and GIS technology

9 APPLICATION OF THE SCIENTIFIC METHOD TO ENVIRONMENTAL ISSUES The Scientific Method Ask Question Research Hypothesis Procedure/Method Gather Data Conclusions Dissemination Application of Method in our Project Can we identify hazardous slopes in Washington County? Learn about geologic factors contributing to slope failure and hazardous conditions. Learn new technologies. We expect to find evidence of potential failure at sites composed of weak rock with steep slopes. Produce a map identifying steep slopes of shale that are within 50 feet of roadways (populated areas) in Washington County. Make observations -Collect data to verify rock type, slope steepness and other evidence of hazardous conditions Analyze data and describe conclusions. Was our hypothesis supported? Creation of reporting products to share results. CURRICULUM

10 RELATIONSHIP BETWEEN GEOLOGICAL PRINCIPLES AND ENVIRONMENTAL ISSUES What is Environmental Geology? Geology: the science which deals with the physical structure and substance of the earth, their history, and the processes which act on them. [Oxford Dictionary] Environment: the surroundings or conditions in which a person, animal, or plant lives or operate. [Oxford Dictionary] Environmental Geology: The study of how natural workings of the physical earth apply to the problems that we face in dealing with our environment. CURRICULUM

11 What is a natural hazard? NATURAL HAZARDS: EFFECTS ON HUMANS AND THE ENVIRONMENT An event resulting from a natural process that has a negative impact on humans and our environment. A human component is necessary. A naturally-occurring event that does not impact humans is merely a natural phenomenon. What are the effects of a natural hazard? Injury or loss of human life. Economic impact due to property damage. Degradation of the environment in which we live. CURRICULUM

RELATIONSHIP BETWEEN HUMANS AND THE ENVIRONMENT Increase in Human Population Forces expansion into geographic areas that may be less stable Human activities impact processes in the natural world

12 RELATIONSHIP BETWEEN HUMANS AND THE ENVIRONMENT Increase in Human Population Forces expansion into geographic areas that may be less stable Human activities impact processes in the natural world Natural processes impact human population Human Population Growth Increased Chance Of Disaster Circular Cycle Expand into Larger Geographical Area Effects on Physical World Increase in Human Activity CURRICULUM

display geographical information GPS coordinates were used by team members to locate sites mapped with ArcGIS

13 DEMONSTRATE THE ABILITY TO UTILIZE GLOBAL POSITIONING SYSTEMS AND GLOBAL INFORMATIONAL SYSTEMS TECHNOLOGY Skills learned in a new (to team) software program allowed utilization of GIS technology to analyze and display geographical information GPS coordinates were used by team members to locate sites mapped with ArcGIS as potential failure sites CURRICULUM

14 TECHNOLOGY

15 SPECIALIZED TOOLS UTILIZED DURING PROJECT ArcGIS Software Global Positioning System Tiltmeter iphone App Digital Photography Adobe Photoshop Google Earth Microsoft Powerpoint Software Internet Use of ArcGIS to create a map of steep slopes with shale as a major component that lay within a 50 buffer zone of roads required learning a new program Learned to use GPS coordinates as a means to locate potential slope hazard sites during field visits Learned to use the new tiltmeter to measure angle of elevation to document slope steepness at sites Digital photographs were taken of the hillslopes visited Digital images were resized for use on the website New techniques in Google Earth were learned in the creation of a virtual tour for the project website Skills in the development of a Powerpoint Presentation were re-visited and enhanced The internet served as a resource for information and the team learned basic information on website creation TECHNOLOGY

16 METHODOLOGY

17 TIMELINE, PROCESS & DIVISION OF LABOR Feb 4-8 Develop Initial Proposal Planning: Team Powerpoint: Nicole S. Feb Feb Research & Learn Technology Produce Hazard Map Topic Research: Team Learn GIS Technology: Team ArcGIS Mapping: Jennifer L. Google Map: Jennifer L. Feb 25 - Mar 15 Mar 4-22 Contact Community Resources Mar Field-Check Identified Sites Apr 8 - May 2 Reach Conclusions Share Results and Information By Phone or Interview: Nicole S. Observations & GPS: Team Photos: Christine G. Data Recorder: Lauren M. Analysis of Data and Discussion: Team Website: Lauren M. Powerpoint Presentation: Christine G. & Jennifer L. METHODOLOGY

18 PROJECT RESULTS

19 RESULTS OF INVESTIGATION No signs of imminent hazard were present (at least none that could be identified by the team). No evidence of recent slope movement There were substantial deposits of small, loose pieces of shale, but no evidence of recent deposit Shale was found on slopes at angles up to 45 degrees, but the rock was of sufficient size that it would take a large force to initiate abrupt movement Water was present in the area, but not in abundance No evidence of undercutting was seen RESULTS

20 Along Hwy 71 South of Westfork PHOTOS OF SITES INVESTIGATED RESULTS

21 PHOTOS OF SITES INVESTIGATED Hwy 71 Debris Pile RESULTS

$fracture or sink hole?$

22 PHOTOS OF SITES INVESTIGATED Evidence of Creep Under I-540 bridge just south of Hwy 74 Evidence of fracture or sink hole? RESULTS

23 SITE WITH MITIGATION TECHNIQUES Private Property Site on Hwy 71 With Terracing and Vegetation RESULTS Lined ditch created to direct water flow and prevent undercutting of slope

24 MATERIALS PRODUCED BY PROJECT Public website with information on hillslope stability Maps in ArcGis and Google Earth identifying potential slope hazard sites in Washington County, Arkansas Google Earth Tour of site field-checking Powerpoint slideshow presentation of project goals, methodology, outcomes and informational content related to potential hillslope failure RESULTS

25 SKILLS GAINED FROM PROJECT EXPERIENCE Teamwork Skills - Members of the team worked together to divide responsibilities and assist other in task completion. Communication skills - Enhanced due to the need to share technical information in a way that could be easily understood. Technological Skills Team members learned to use new technology such as GIS and GPS. Skills in preparation of presentation material (slideshow, google tours, etc.) were learned and/or enhanced by team members. RESULTS

26 Does your presentation convey a knowledge of your subject matter greater than that of your audience CONTENT KNOWLEDGE

27 RELATE GEOLOGICAL PRINCIPLES TO ENVIRONMENTAL ISSUES What factors contribute to slope failure? Steep slopes are out of equilibrium with gravity and WILL eventually fail. Weak bedrock such as shale is particularly susceptible to failure. Other factors (soil type, weathering, erosion, water) can exacerbate the failure process. When is slope failure an environmental issue? When the event occurs in proximity to human population, creating a hazard to life and property. CONTENT

SHALE: COMPOSITION AND CHARACTERISTICS A layered sedimentary rock deposited in shallow seas that covered the area during the Mississippian Period, about 325 million years ago.

28 SHALE: COMPOSITION AND CHARACTERISTICS A layered sedimentary rock deposited in shallow seas that covered the area during the Mississippian Period, about 325 million years ago. CURRICULUM a clastic rock made up of claysize weathering debris [Clastic - term for rocks composed of broken pieces of older rocks] The process in the rock cycle by which shale is formed is known as compaction. Clay minerals line up with each other in such a way that the rock splits easily on one plane, typically breaking into very small, thin flat pieces. Shale is slick and slides easily on wet surfaces

destructive, continuous movement of slopes down inclined planes CURRICULUM Evidence of

29 SLOPES AND MASS WASTING Slump occurs when material rotates along a curved surface; can be bedrock, but usually soil Slump will eventually turn into flow Creep is a slow, but destructive, continuous movement of slopes down inclined planes CURRICULUM Evidence of creep includes bent trees and leaning poles Creep is a continuing maintenance problem

30 Define Hazard Zone MASS WASTING: MITIGATION TECHNIQUES Confirm slope steepness gentle slopes do fail, but failure on steep slopes is more likely Identify material present (is the rock weak, like shale?) Determine if there is evidence of previous slide in identified, or immediately adjacent, location Is the site in close proximity to human activity? Evacuate hazardous area and/or post warnings CURRICULUM

31 Creep Slump CURRICULUM EVENT SPECIFIC MITIGATION Fix small cracks as they appear. Deep foundation repair Put in retaining wall with a gravel pack and weep hole Debris Flow Attempt to re-direct the flow with channels and retention basins Block Glide / Rock Fall Attempt to bind large rock more tightly using bolts to anchor slope Cover area with mesh to keep smaller rocks from falling into roads

32 ACKNOWLEDGEMENTS

33 ACKNOWLEDGMENTS Dr. Robyn Dennis CAST University of Arkansas, Fayetteville Mark Lane Civil Engineer, City of Searcy, Arkansas Paul Lowrey Science & Math Faculty/GIS Facilitator Northwest Arkansas Community College, Bentonville, AR C. Dianne Phillips Science & Math Faculty, EAST/EMPACTS Facilitator Northwest Arkansas Community College, Bentonville, AR

34 APPENDIX

35 REFERENCES Disaster, Planning and Development: Managing Natural Hazards to Reduce Loss Environmental Geology Course Material News and Information about Geology Physical Geography Slope Stability, Triggering Events, Mass Movement Hazards

36 RECOMMENDED LINKS Project Website Final Presentation Slope Hazard Fact Sheet Photos of Site Visits Google Earth Tour of Sites Videos Slow Avalanche: Additional Reading Landslide Hazards: Landslide Hazard Information: Slope Stability: Photos Landslide Blog:

Illegal Dumpsite Map and Informational Website

Illegal Dumpsite Map and Informational Website Dominick Elkins, Faith Cordes, and Shweta Shah Environmental Geology, EMPACTS: Professor Paul Lowrey Fall 2015, NorthWest Arkansas Community College, Bentonville,