Design and Modeling of a Landfill Cover
using Salix for Hydrologic Control,
Biomass Production and Land
Reclamation:
Solvay Wastebeds, Syracuse, NY
Douglas J. Daley, P.E.
State University of New York College of
Environmental Science and Forestry
Syracuse, NY
American Society of Agricultural Engineers Annual International Meeting July 18, 2005
Presentation Outline
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


Project Background and Objectives
Field Demonstration Trial Results
Modeling and Evaluation of Design
Elements
Summary
Project Goal and Objectives
•
Evaluate the feasibility of large-scale willow
biomass crop production on a former waste
disposal site to improve stormwater control,
reduce leachate generation, enhance
recreational opportunities and produce biomass.
•
•
•
Screen willow varieties suitable for wastebed
environment.
Determine the effectiveness of Salix for hydrologic
control in an ecologically engineered, alternative
landfill cover system.
Measure and model the effect of short rotation
woody crop (SRWC) management strategies and
three organic soil amendments on
percolation/leachate generation.
Project Site Location
Syracuse, NY
N 43o 04’ 26” W 076o 14’ 58”
Solvay Process Residues



Solvay process to produce
soda ash 1887 -1986
Primarily a non-hazardous
mixture of calcium, magnesium
and sodium compounds
Waste Beds 9 to 15




15 to 21 m deep
270 ha (662 acres)
Elevated chloride levels in
leachate and stormwater
Stressful growing conditions


pH (8.0 – 12.3)
Electrical conductivity
(0.5 – 9.2 dS/m)

Organic matter (0 - 3.9%)
Landfill Cover Systems:
Conventional vs. Evapotranspiration

Reduce percolation
(leachate)
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

Conventional systems rely
on low permeability soil
and geomembrane
Alternative systems
enhance evapotranspiration
Issue: Long-term
reliability, flexibility,
sustainability
Evapotranspiration (ET) Landfill
Cover

The role of willow
PPT = (E + T) + RO + DS + D
Evaporation is positively influenced by
increasing leaf/stem area and promoting
interception.
Evaporation through advection is
enhanced in multi-story canopies.
Benefits of Salix


One of the first woody
species to establish naturally
Tolerant of harsh site
conditions on site (elevated
chloride and pH)
Naturally established willow and
poplar on the Solvay waste beds.
Design: Willow Selection
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High growth rates
High stem density
High transpiration rates
Genetic diversity

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SUNY ESF long history of
research in short rotation
woody crop for biomass
Select desired traits to
match project design
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First-year growth from cuttings (Trial Field
1, May 2005)
Survival
Below-ground biomass
(consider root : shoot
ratio)
High water use
“efficiency” (e.g. high
water use : biomass ratio)
Design: Growth and Yield Field
Trials
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Two 2-acre fields (2004)
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Multiple Salix varieties
selected from greenhouse
trials (2003)
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First-season’s growth of willow on
biosolids-amended Solvay waste (Fall
2004)
biosolids-amended (1986)
unamended Solvay waste
Two cutting lengths to test
rooting depth and survival
(25 and 50 cm)
High planting density

15,000 stems/ha (6,000
stems/ac)
First-year Survival of Willow on
Biosolids-amended Waste
120
25 cm
50 cm
Survival (%)
100
80.1% survival
on unamended
waste (Field 2)
80
60
40
20
0
-66 37-77 70-23 71-26 71-31 S 365 SV1SX 61SX 64
1
0
98
98
98
98
981
Salix varieties
First Year Growth of Willow on
Biosolids-amended Solvay Waste
(Field 1)
100
80
2
Basal area (cm /plot)
25 cm
50 cm
60
40
20
0
7
3
6
1
6
65 SV1 X 61 X 64
01-69837-79870-29871-29871-3 S 3
S
S
1
8
9
Salix varieties
Average basal area
on Field 2
(unamended waste)
(1.2 cm2/plot)
Using Sap Flow to Measure
Transpiration
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Stem heat balance
method
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Three-year old willow on
mineral soil (control)
Sensor sizes range from 10
- 35mm
Measure: sap flow
(g/hr/stem) and stem
diameter frequency
(stem/ha)
Compute: Stand-scale
sap flow (l/day)
9/1
6/ 2
9/1 004
9/ 2
00
9/2
4
2/ 2
9/2 004
5/ 2
00
9/2
4
8/ 2
10 004
/1/
2
10 004
/4/
20
04
10
/7/
20
10
04
/10
/20
10
04
/13
/
10 2004
/16
/20
10
04
/19
/
10 2004
/22
/
10 2004
/25
/20
10
04
/28
/
10 2004
/31
/20
04
11
/3/
2
11 004
/6/
20
04
11
/9/
20
11
04
/12
/
11 2004
/15
/20
04
Sap flow (l/day)
Stem Size Differences in Late
Season Sap Flow for One Variety
4
3.5
3
2.5
2
1.5
1
0.5
0
SX64, 16mm sap flow l/day
SX64, 25mm sap flow l/day
SX64, 35mm sap flow l/day
Time (day)
5/
6/
2
5/ 005
8/
2
5/ 005
9/
5/ 2 00
10 5
/
5/ 200
11 5
/
5/ 200
12 5
/
5/ 200
14 5
/
5/ 200
15 5
/
5/ 200
16 5
/
5/ 200
17 5
/
5/ 200
18 5
/
5/ 200
20 5
/
5/ 200
21 5
/
5/ 200
22 5
/
5/ 200
23 5
/
5/ 200
24 5
/
5/ 200
26 5
/
5/ 200
27 5
/
5/ 200
28 5
/
5/ 200
29 5
/
5/ 200
30 5
/2
00
5
Sap flow (g/hour)
Sap Flow: Early Season
1400
1200
1000
800
600
400
200
0
Time (days)
SX64, 35mm, sensor 7
SX64, 35mm, sensor 16
SX64, 35mm, sensor 15
Stem Diameter Distribution to
Determine Stand-level Sap Flow
20000
S25
SV1
SX64
18000
14000
12000
10000
8000
6000
4000
2000
>4
0
37
_4
0
34
_3
7
31
_3
4
28
_3
1
25
_2
8
22
_2
5
19
_2
2
16
_1
9
13
_1
6
10
_
13
0
<1
0
Number of stems ha-1
16000
Diameter class (mm)
Sensor sizes (16, 25, 35 mm)
Late Season Willow Transpiration
(October-November 2004)
Salix Variety
Sap Flow
(l/d/plant)
S25
Sap Flow
(mm/month)
180
SV1
65
1.2
SX64
131
2.5
Equivalent
transpiration
3.4
350,000 – 968,000
gal/acre/season
Simultaneous Heat and Water
(SHAW) Model
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Humid climate
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30-yr Average Annual PPT =
978 mm
PET:P = 1.3
Model simulates heat and
water transfer through soilplant-air continuum
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Freeze-thaw
Management
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Salix as short-rotation woody
crop (SRWC)
Even-age vs. 3-year
harvesting rotation
Soil modifications with
organic amendments (mulch
and biosolids)
(Figure supplied by USDA)
Preliminary Model Projections
Deep percolation
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
Mean: 978 mm
SD: 165 mm
Precipitation
No vegetation
19
75
19
77
19
79
19
81
19
83
19
85
19
87
19
89
19
91
19
93
19
95
19
97
19
99
20
01
Water (mm)
Different management regimes
Year
Uniform Stand
3-YR Harvest
Rotation
Summary
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Willow (Salix) is successful when organic
amendments are incorporated into Solvay waste
Late season transpiration by willow is important
to the water balance
Preliminary model results indicate that Salix
minimizes deep percolation throughout a long
growing season.
Evaluate other design elements to address
extreme wet weather events.
Acknowledgements
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Sponsor: Honeywell International
Co-investigators: Timothy Volk, Lawrence
Abrahamson
Graduate Students: Andrew Johnson, Jaconette
Mirck,
Engineering Consultants: O’Brien & Gere