1. TAG Proposal “Forest vegetation as an indicator of natural gas leaks” Don Davis (PI) Lynda Farrell, Consultant

2. GAS WELL DRILLING: POTENTIAL ADVERSE FOREST EFFECTS
Gas Wells
60% Forested

3. GAS WELL DRILLING: POTENTIAL ADVERSE FOREST EFFECTS 1
GAS WELL DRILLING: POTENTIAL ADVERSE FOREST EFFECTS 1. Pad Site Logging & Construction
Removal and Sale of Trees

4. Logging Wounds on Residual Trees at Edge
1. Direct Effects
2. Secondary Effects

5. 2. Excavating & Grading
“Edge Effects”
Surface Water Flow Changes

6. “Edge Effects” (Tree Mortality Along Edge)
Mortality not necc from salt, etc.
May continue for years

7. 3. Leaks & Spills of Brine (+ Frac’n Chemicals?)

8. Leaks from Lined Pits
Deer Attracted to Salt

9. Salt Damage

10. 4. Precursors to Ozone Formation (i. e
4. Precursors to Ozone Formation (i.e., NOx Emissions from Compressor Stations)
Tons/Yr
Tons/Yr
Source: PA DEP (2010)

11. Ozone-Sensitive Plants
Black Cherry
Chinese Tallowtree

12. Vegetation Associated with Pipelines
Excavation
Clearing

13. Seeding
Grading
Establishment of
Grasses, clover, etc.

14. Common Perennial Plants on PA Pipeline Corridors
Vetch
Grass
Trefoil
Grass
Clover

15. So, what happens if there is a leak in a natural gas pipeline?
Gas migrates
upward in an
inverted cone
Root Death
• Soil atmosphere
• Soil oxygen
depleted
• Methanobacter
(+ Size of leak,
Pressure, etc. etc.)
**OLD** Pipelines

16. Underground Leak
Aerial View Pattern
Influenced By
• Soil Texture
• Soil Disturbance
Within Trench
• Soil Moisture
• Depth of Freezing
**OLD** Pipelines

17. Woody Shrubs Over Old Pipelines

18. SUMMARY: Early Detection of Leaks Using Dead, Dying, or Discolored Vegetation Above Leaking Natural Gas Pipeline

19. TAG Proposal “Forest vegetation as an indicator of natural gas leaks”
• 1. Outreach Activities
Presentations at meetings
Prep of publications, brochures, etc.
• 2. Aerial surveys above old pipelines to locate patterns of discolored or injured vegetation
• Follow-up with ground-truth surveys