Transcript Dynamics of Product Water Chemistry & Defining Native

Dynamics of Product Water
Chemistry
&
Defining Native Wetland Species Salt
Tolerance and Water Use Rates
Holly Sessoms
General Chemistry:
CBM product water is sodium
bicarbonate rich. When discharged
to the surface or applied to the soil,
sodium bicarbonate undergoes the
following reaction:
NaHCO3-
H+ + CO3-- + Na++
Free carbonate (CO3) in solution is now
available to bind with calcium in the
surface water or soil to form calcium
carbonate (CaCO3):
Ca++ + CO3--
CaCO3
Calcium carbonate is relatively insoluble
and precipitates from solution, thereby
increasing the SAR.
The dissolution of sodium bicarbonate
also causes the pH to increase with the
formation of sodium hydroxide:
Na++ + H+ + CO3--
CO2 + NaOH-
Change in water chemistry for three water
qualities over a 9 day time period
(subject to evapoconcentration).
Initial vs.
Final pH
Initial vs.
Final EC
(dS/m)
Initial vs.
%
%
%
Final SAR Change Change Change
EC
SAR
pH
Powder
River
7.4 / 8.1
3.07 / 3.75
3.7 / 4.4
22.15
18.92
9.5
CBM
7.7 / 8.4
3.36 / 4.01
12.5 /
18.0
19.35
44.00
9.1
Salinesodic
CBM
7.5 / 9.1
5.42 / 6.71
20.7 /
33.8
23.80
63.29
21.3
21.77 42.07
13.3
Average
% Change:
Change in product water chemistry - from
discharge to irrigation nozzle:
•Source
•pH
•SAR
•EC
•mmhos/cm
•Outfall
•7.5
•20-26
•3.8-4.2
•Pump
•8.2
•27-30
•2.6
•Irrigation
Nozzle
•8.7
•32
•2.9
•16%
•23-60%
•24-31%
•Average %
Change
(outfall to
nozzle)
•Aaron Dejoia,
Cascade Earth
Science
Changes in product water chemistry - from
discharge to downstream location:
Mean values
Sue Draw
DC 1
Site 3
Site 4
(below res.)
% Change:
(discharge to
Site 4)
pH
--
EC
dS/m
SAR
practical
SAR
true
7.13
4.30
24.76
33.5
8.54
4.20
29.74
44.1
9.15
4.27
32.46
53.4
28.3%
<1%
31.1%
59.4%
increase
decrease
increase
increase
Source: Patz, Marji J. Coalbed Methane Product Water Chemistry on Burger Draw, Wyoming, M.S.,
Department of Renewable Resources. University of Wyoming. May, 2002.
Suggested range in EC and SAR of
irrigation water for various soil textures:
Soil Texture
Very Coarse
sand, loamy sand
Coarse
sandy loam
Medium
loam, silt loam
Medium fine
clay loam, sandy clay loam
EC range
(mmhos/cm)
SAR upper limit
Flood
Sprinkler
Flood
Sprinkler
0-4
0-5
18
24
0-3
0-4.5
12
15
0.2-2.5
0-3
12
15
0.3-2.5
0.2-3
8
12
0.5-2
0.3-2.5
6
9
Fine
Silty clay loam, sandy
clay, clay, silty clay
Source: Western Fertilizer Handbook
Discharge standards as of April 25th, 2003 :
Irrigation Season
– Powder River
• Max EC 2.5 dS/m
• Max SAR 6.0
Non-Irrigation Season
– Powder River
• Max EC 2.5 dS/m
• Max SAR 9.75
– Tongue River
• Max EC 1.5 dS/m
• Max SAR 4.5
– Tongue River
• Max EC 2.5 dS/m
• Max SAR 7.5
Reduce product water volumes
through the use of halophytic
wetland species, thereby obtaining
an economically viable volume of
water for treatment methods while
enhancing wetland function.
Objectives:
Identify appropriate wetland species
Define the maximum salt tolerance of each
species
Determine water use rates relative to open
water evaporation
Determine how wetland design may
optimize plant health – water table height
Determine the extent of salt accumulation
in plant tissue, ion selectivity?
Determine if stratification does occur and
to what extent
Halophyte Background:
Halophytes are plants found
growing under naturally saline
conditions (Aronson, 1989) and
are sodium tolerant.
Patz et al., 2002 found that CBM
product water, released into a
channel, will alter plant species
composition by favoring salt
tolerant wetland and riparian
plants.
Halophyte Background:
Of these wetland species,
American bulrush,
Maritime bulrush, Baltic
rush, Cattail, Inland
saltgrass, Prairie
chordgrass, and Nutall’s
alkaligrass appeared to
be thriving (Patz et. al.,
2002).
Summary of reported salt tolerance and water use:
Species
Reported salinity
tolerance
Scirpus americanus
(American bulrush)
42.5 dS/m (Duncan, 1974)
Scirpus maritimus
(Maritime bulrush)
77 dS/m (Duncan, 1974)
Juncus balticus
(Baltic rush)
Tolerates ‘brackish’ water (Duncan,
1974)
Typha latifolia
(Cattail)
22.5 dS/m (Hootsmans and
Wiegman, 1997)
‘some salinity’ (Duncan, 1974)
Distichlis spicata
(Inland saltgrass)
70 dS/m (Aronson, 1989)
Spartina pectinata
(Prairie chordgrass)
Tolerates ‘brackish’ water (Duncan,
1974)
Puccinellia nuttalliana 11.0 dS/m (Ungar, 1974)
‘has salt tolerance’ (Aronson,
(Nutall’s alkaligrass)
1989)
ET Rate
6.6 mm/day to 13.8 mm/day (Towler, 1999)
10-12 mm/day (Allen et al., 1992)
4-12 mm/day (Snyder and Boyd, 1987)
3-10 mm/day (Pauliukonis and Schneider,
1999).
6.6 mm/day to 13.8 mm/day (Towler, 1999)
Hypotheses:
Native halophyte water use rates will exceed
evaporation rates and species will tolerate
elevated salinity levels over that of “average”
CBM product water.
Constructed wetlands can be utilized to reduce
product water volumes, thereby increasing the
feasibility of other water management options
while providing a beneficial use.
Design:
7 native wetland species
Columns constructed of 10”
PVC pipe, 40 inches deep
Gravel substrate
Randomized block design
4 Replications, 16 columns per
replication
2 “blanks” per replication
2 open surface evaporation
pans
Study Protocol:
• Planted starter plants Jan. 27, 2003
• All columns filled with tapwater
• When plants no longer appeared dormant, began
watering with CBM water (Feb. 18th)
Study Protocol:
Progressively sodic water chemistry:
Initial: SAR=11.6 , EC=3.10 , pH=8.3
Mid: SAR=23.0 , EC=3.50 , pH=8.1
Final: SAR=36.0 , EC=3.53 , pH=8.0
Water plants once per week
Allowed for “drawdown” in 18” water table
columns
Continuous accumulation of salts through
evapoconcentration
Study Protocol
Treatments:
 Seven Plant Species
 Two water tables: at the
surface, 18” below the
surface
 Depth of sampling
Monitor:
Water use rates once per week
Plant health - thickening of leaves, leaf burn, lack of
water uptake, death
Biomass production - harvest plants every 8 weeks
(or when plants start to seed)
Plant salt uptake and preferential selectivity of ions
Collect water samples once per month at three
depths within the columns - stratification?
Expected Results:
Salinity and water table tolerance will allow for some
prediction of riparian community succession in
channels receiving product water.
Salinity tolerance and water use rates will provide
some baseline data.
Allow for prediction of the feasibility of constructed
wetlands for treatment of product water.
So what have we learned so
far?
18” water table doesn’t work:
Plants appear to die
from lack of water
27 of 28 treatment
columns are dead
Average weekly water use rates of all treatments and average pan
evaporation from first harvest to second harvest.
4500
Blank
Inland saltgrass
Baltic rush
Nuttall's alkaligrass
American bulrush
Maritime bulrush
Prairie chordgrass
Cattail
Pan Evap.
4000
3500
Water Use (mL)
3000
2500
2000
1500
1000
500
0
0
1
2
3
4
Week
5
6
7
8
Harvest
Ratio of treatment water use to pan evaporation at plant maturity (7th
week of growth).
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
Blank
Saltgrass
Baltic Rush
Alkaligrass
American
bulrush
Treatment
Maritime
bulrush
Chordgrass
Cattail
Water use (mL) per gram of biomass produced.
450
400
350
300
250
200
150
100
50
0
Distichlis spicata Juncus balticus
Puccinellia
nuttaliana
Scirpus
americanus
Treatment
Scirpus
maritimus
Spartina
pectinata
Typha latifolia
Average pH values per treatment over a 3 month sampling period.
8.4
pH Blank
pH Saltgrass
pH Baltic rush
pH Alkaligrass
pH American bulrush
pH Maritime bulrush
pH Chordgrass
pH Cattail
8.3
8.2
8.1
pH
8
7.9
7.8
7.7
7.6
7.5
7.4
5/9
5/19
5/29
6/8
6/18
Date Sampled
6/28
7/8
7/18
Average EC values (dS/m) per treatment over a 3 month sampling
period.
8
EC Blank
EC Saltgrass
7.5
EC Baltic rush
EC Alkaligrass
EC American bulrush
EC Maritime bulrush
7
EC Chordrass
EC (dS/m)
6.5
EC Cattail
6
5.5
5
4.5
4
5/9
5/19
5/29
6/8
6/18
Date Sampled
6/28
7/8
7/18
Average SAR values per treatment over a 3 month sampling
period.
21
SAR Blank
SAR Inland Saltgrass
20
SAR Baltic rush
SAR Alkaligrass
Sodium Adsorption Ratio
19
SAR American bulrush
SAR Maritime bulrush
18
SAR Chordgrass
SAR Cattail
17
16
15
14
13
12
5/9
5/19
5/29
6/8
6/18
Date sampled
6/28
7/8
7/18
Gee whiz:
Constructed wetland
= ½ a football field
can consume 11,520
gallons of water per
day.
Jim Bauder
Bauder crew
BLM
DOE