Transcript Flux through Peat An investigation into fluid flow in the Serpentine Bog, Belgrade Lakes Watershed, Maine.

Flux through Peat
An investigation into fluid flow in the
Serpentine Bog, Belgrade Lakes
Watershed, Maine
Belgrade
Lakes
• A – Maine
• B – Belgrade
Lakes
Watershed
• C – Surficial
Geology
• D – Bedrock
Geology
Site Description
Serpentine Bog Corridor
Cross Section
Hydraulic Head
Darcy’s Law
Q  KA
dh
dl

Discharge (Q)
Cross-sectional area (A)
Hydraulic gradient (dh/dl)
Constant (K)
Northern Transect
Hydraulic Head
and
Weather Data
Southern Transect
Serpentine Datalogger
Weather
Slug Tests
Piezometer
T37
Conductivity
(hours)
(cm/s)
N1d
<2
1.18E-04
N2d
71.4
3.30E-06
N3d
17.3
1.36E-05
N4d
9.3
2.55E-05
S1d
3.5
6.67E-05
S2d
67.5
3.49E-06
S3d
<1
2.36E-04
S4d
<2
1.18E-04
21.8
7.30E-05
Average
Northern Transect
Southern Transect
Serpentine Datalogger
Numerical Modeling
Why?
(1) Test hypotheses about groundwater flow through a system
(2) Predict how the system would respond to different conditions
How?
(1) Finite Difference Grid
(2) Properties and Boundaries
(3) Calibration
(4) Additional Models
Column
Row
Hydraulic Properties
Slug Tests
Cross Section
Layer 1
Row 17
Boundaries
Base Model Results
Groundwater Map
(Layer 1)
Surface Water Head = 9.71 m
Recharge = 1347 mm/year
Velocity Map
(Layer 1)
Velocity Map
(Row 3)
Calibration
Runs 1 & 2
Surface Water Head = 9.71 m
Recharge = 2353 mm/year
Surface Water Head = 9.71 m
Recharge = -86 mm/year
Groundwater Map
Layer 1 Velocity
Row 3 Velocity
Runs 3 & 4
Surface Water Head = 10.02 m
Recharge = 1347 mm/year
Surface Water Head = 9.58 m
Recharge = 1347 mm/year
Groundwater Map
Layer 1 Velocity
Row 3 Velocity
Conclusions
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Geometry
K = 3.49*10-6 cm/s to ~2.36*10-4
cm/s
General ideas on fluid flux
Effect of water table and
precipitation on system
Temporal changes > spatial
changes
How much faith should be placed
in any numerical model?
Acknowledgements
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Dr. Jennifer Shosa
Dr. Bruce Rueger, Dr. Robert Gastaldo and Alice Ridky
Dr. Whitney King
Katie Curtis and Dan Pace
Jerry and Betsy Tipper
East Pond Association
ACS-PRF Grant # 40810-GB8
Hydraulic Head [Elevation above 0 datum (m)]
Average
StdDev
Max
T37
Min
Conductivity
(hours)
(cm/s)
N1d
9.88
0.11
10.17
9.77
<2
1.18E-04
N2d
9.93
0.10
10.17
9.85
71.4
3.30E-06
N3d
9.84
0.01
9.86
9.83
17.3
1.36E-05
N4d
10.02
0.05
10.12
9.96
9.3
2.55E-05
S1d
9.96
0.11
10.24
9.85
3.5
6.67E-05
S2d
9.87
0.09
10.07
9.76
67.5
3.49E-06
S3d
10.01
0.12
10.19
9.84
<1
2.36E-04
S4d
9.95
0.06
10.16
9.78
<2
1.18E-04
Piezometer Average
9.93
0.08
10.12
9.83
21.8
7.30E-05
Serpentine Gauge
9.71
0.14
10.02
9.58