Natural Restoration of Peat and Re-usability of Fill Material After Road Reclamation on a Fen Terry Osko, Circle T Consulting, Inc. Corey Vogel, Cenovus Energy (formerly with Suncor Energy) Jenna Pilon, University of Waterloo Rich Petrone, University of Waterloo Catherine La Farge, University of Alberta Krista Williams, University of Alberta Josh Martin, Suncor Energy Sustainable Peatlands for In Situ Oil Sands, NAIT Boreal Research Institute, Sep 3, 2014, Peace River
Transcript
Natural Restoration of Peat and Re-usability of Fill Material After
Road Reclamation on a Fen Terry Osko, Circle T Consulting, Inc.
Corey Vogel, Cenovus Energy (formerly with Suncor Energy) Jenna Pilon, University of Waterloo
Rich Petrone, University of Waterloo Catherine La Farge, University of Alberta
Krista Williams, University of Alberta Josh Martin, Suncor Energy
Sustainable Peatlands for In Situ Oil Sands, NAIT Boreal Research Institute, Sep 3, 2014, Peace River
Outline
Project overview
Road removal
Road fill assessment
Peatland physical property and hydrologic assessments
Propagule Study
Implications
Project Overview Backround
General Description Considerations
Process
Background/Rationale Growing interest and regulatory requirements for reclamation of clay pads and associated facilities back to peatland
Desire for continued improvement
Reduce impacts of facilities left in place, such as impeded water flow, change in water chemistry
Though growing, knowledge and practice is still deficient; much yet to learn
Learning sometimes hindered by fear of unknown
Big watery holes
Is fill reusable? Reuse economical?
Project Description Suncor Firebag Project area
Gravel-capped clay fill road on fabric liner over fen peatland.
250 m long
6 years old
Clay thickness: 1.4 – 1.7 m
Compressed peat thickness: 0.7 – 1.4 m
Underlain by sand
Evidence of vegetation mortality due to flooding on the upstream side
Objectives
Remove fill entirely
Re-use the fill
Achieve natural revegetation of re-exposed peat to an acceptable peatland community
New peatland community naturally sustainable by restoration of suitable hydrologic regime
Basic Study Methods Installed instrumentation prior to excavation to make initial observations
Atmospheric conditions, water table elevation and flow, soil moisture, soil temperature, water chemistry
Removed road fill, tested material for re-use
Sampled peat on and off road for physical property testing
Installed instrumentation on newly exposed peat
Sampled peat on and off road for propagule viability
Continued observations
Road Removal Description of process
What was observed
Road Fill Assessment Sampling
Testing
Results
Soil Sampling Positions
Depths: 0-25 cm 25-50 cm 50-75 cm 75-100cm 100-125 cm 125-150 cm
Soil Sampling
Sampled at 4 locations along road length
Collected about 1 kg of soil at each depth increment
Sent to engineering lab for analysis
• Maximum compactability
• Optimum moisture
• Actual moisture
Soil Moisture and Density Analysis
Estimated maximum density:
1844 (kg/m3)
Estimated optimum moisture to achieve max density: 13.8%
Moisture of samples:
• Mean = 11.5%
• Range = 8.1% - 14.2%
• (2 of 72 samples >13.8%)
(From: AB Transportation Method TLT-413 (02))
Moisture Trends in Road Profile (% moisture)
Upstream Shoulder
Middle Downstream
Shoulder Depth Average
0-25 cm 9.4a1 9.0a1 10.3a1 9.5a
25-50 cm 10.9b1 10.5b1 12.7bc2 11.4b
50-75 cm 10.0a1 11.8c2 11.7b2 11.2b
75-100 cm 11.9bc1 11.8bc1 12.9bc1 12.2c
100-125 cm 12.4c1 11.5bc1 12.7bc1 12.2c
125-150 cm 12.3c1 12.2c1 13.4c1 12.6c
Position Average
11.11 11.11 12.22
Fill Volumes
Total volume of fill removed (m3):
Gravel: 181
Mud, organics, liner material: 987
Useable clay: 4866
Useable clay as a proportion of clay fill = 83.1%
Peatland Physical and Hydrologic Responses
Instrumentation Sampling
Lab Procedures Results
Instrumentation
Measurements Met Station
Ambient temperature, wind speed and direction, relative humidity, net radiation (all-wave and photosynthetically active), soil temperature (5, 10, 25, 50, 100 cm depths)
Remote Stations (25 and 50 m on either side of road) Air temperature, relative humidity, soil temperature (5, 10, 25, 50 cm)
Water wells (frost free season) Continuous water table elevation, weekly soil temp, soil moisture, depth to frost
Chemistry: major cations/anions, DOC/DIC, N, P
“Squishy-meters” Peat surface fluctuation
Peat Sampling Physical Properties:
• Bulk density
• Particle size
• Porosity
• Specific yield
• Moisture retention
• Hydraulic conductivity
“Squishy-meter” • Measure distance
from top of bar to plate
• Change in distance represents compression or decompression
• Installed in both road and off-road locations
Ground Surface and Ground Water Elevations An initial water table gradient from upstream to downstream
Gradient maintained after road removal
However, former road area forms a depression in water table
Figure 1. Cultured bryophyte species showing two types of growth. Regeneration A-D. from stem lateral initials (Pleurozium schreberi (A,D) from off-road sample 2-6a; dish 84a Sphagnum warnstorfii (B) from shallow off-road sample 3a; jar 62b) or fragmented leaves (S. magellanicum (C) from off-road sample 2-5a; jar 78a). Germination E. from spores (Sphagnum sp. protonema with no old stems/leaves observed).
A B C
D E
Before After: March 2014
Road (bottom) Trial Culture: started Sept. 9th, 2013
Sphagnum sp (brown)., S. magellanicum, Polytrichum sp., Pohlia
Successfully germinated diaspores from peat samples taken from off-road samples. A) Foliose lichen in culture from sample 2-6a (Dish 84b). B) Crustose lichen in culture from sample 4-3a (Dish 32b). C) Fungal fruiting body in culture from stockpile sample 4 (medium depth) (Jar 108b). D & E) Cultured vascular plants seedlings from sample 4-3a (Jar 31a) and sample 1a Shallow Off Road (Jar 71a), respectively. F) Cultured Aulacomnium palustre with close-up of gemmae stalk (asexual propagules) from sample 4-3a (Jar 30b). G) Cultured Amblyodon dealbatus (green) and Sphagnum sp. (white) from sample 2-5a (Dish 80b). Scale bars: a & c = 1 cm; b = 1 mm; d & e = 2 mm; f = 2.5 mm; g = 2.5 cm
A
B C D E
F G
Implications So Far Road fill reusability
Peat response Plant regeneration potential
Application to industry
Road Fill
Bulk of fill (83%) immediately reusable
Soil quality excellent
Much cheaper than a new borrow if the fill can be used nearby
Less footprint than new borrow also, thereby reducing reclamation liability
Excavation was not complicated, probably depends on depth of fill, depth and nature of underlying peat, initial construction
Peat Response
Much still unknown
Physical and hydrologic properties are not far outside of natural ranges
Properties able to restore naturally?
Increasingly likely if appropriate vegetation establishes
Exciting to see how things will evolve
Peat Propagules There are viable propagules within the buried
peat
• Unknown how they may perform in a natural
setting vs growth chamber
Natural encroachment via seed also has good
potential for revegetation
• Seed bank in off-road cores indicates
abundant spore and seed rain
• Observed natural seeding by cotton grass
during excavation
• May indicate timing window
Industry Application Fill is likely re-usable in most cases
Tempered by nature of individual circumstances
Re-usability affected by construction methods (e.g. proper peat loading)
Response of peat and hydrology seems encouraging
Ability of peat to naturally revegetate appears to be high
To be confirmed by vegetation survey on the road
Additional tools can be used to temporarily manage hydrology and to actively revegetate
Overall, results are encouraging and should reduce hesitation to complete fill removal projects
Goodbye… Thanks to: Chuck Symons, Brayford Trucking, Brayford Trucking staff,
Stephen Hodges, Bruce Anderson, Bill Tully, Suncor Energy
Tristan Gingras-Hill, George Sutherland, University of Waterloo
