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Superviso r Associate Professor Ryan Vogwill Evaluation of water and solute (Cl - ) balance for two contrasting wetlands in a semi-arid environment, Western Australia SCHOOL OF EARTH AND ENVIRONMENT Oct 2013 Nathan Senevirathne

Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

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Page 1: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

Supervisor Associate Professor Ryan Vogwill

Evaluation of water and solute (Cl-) balance for two contrasting wetlands in a semi-arid environment, Western Australia

SCHOOL OF EARTH AND ENVIRONMENT

Oct 2013

Nathan Senevirathne

Page 2: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

BMNDRC

The study area is part of Buntine-Marchagee Natural Diversity Recovery Catchment (BMNDRC)

Study area

Regional setting of project area

Page 3: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

W023

W024

Regional setting of project area

Study area sub-catchment(~ 600 ha = 0.02 % of BMNDRC)

W023

W024

Page 4: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Remnant vegetation and landuse

Wheat Plantation Canola Plantation

Lupin Plantation Re-vegetated in 2013 Eucalyptus overstory

Salt – tolerant shrubs

~4%~90%

Page 5: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

The entire study area is a low relief region that lies over Archaean granitic rock of the Yilgarn Craton; ~340 mAHD on WEST and ~290 mAHD on EAST

The typical soil structure is comprised of fresh granitic bedrock grading upwards into saprock and saprolite which are overlain by lacustrine clays, palaeochannel silts, yellow earthy sands (Balgerbine Soil System)

(Anand & Paine 2002)

Basement rocks are exposed only at a small area near western margin and maximum depth is about 35 m

There is only one dyke appearing just outside of south-west margin (Geological Survey Western Australia by Baxter & Lipple 1985)

Geology & Topography• Drilling program carried out in mid 2012• LiDAR data• Geological survey of Western Australia by Baxter & Lipple 1985• The geology, physiography and soils of wheatbelt valleys by Commander et al. 2001• Regolith geology of the Yilgarn Craton, Western Australia: implications for exploration by Anand & Paine 2002

Page 6: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Soil types, dykes and isolated outcrops of granite in the study area (Baxter & Lipple 1985)

Geology & Topography

Page 7: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

The gradient of slope in the study area

Geology & Topography

Page 8: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

A

BC

D

A B

C D

Digital elevation profiles of study area using LiDAR elevation data

Geology & Topography

Page 9: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Groundwater monitoring network

Page 10: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

W023 W024

surface flow that could be generated by a heavy rainfall

Methodology Surface water catchment delineation

Page 11: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Surface water catchment delineation

New Boundary

618 ha

589 ha

Page 12: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Hydrogeochemistry

Water samples were collected from monitoring bores and several wetlands on 30 th April 2013. Electrical Conductivity (EC), Oxidation-Reduction Potential (ORP), pH, and temperature were measured at the field.

Ion chromatography using Dionex DX500 systems to determine the concentrations of major cations and anions

   Na-Cl type

waters

Na-Cl type

waters

Page 13: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Dominance of Cl-, Na+, SO42-, Mg2+ and HCO3

- in water samples

Methodology Hydrogeochemistry

Molar Cl/Br ratios vs. Cl- concentrations (mol/L) in water samples collected from groundwater and wetlands

Page 14: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Distribution of Total Dissolved Solids (TDS) in study area

Methodology Hydrogeochemistry

Page 15: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Surface water in-flow Surface water out-flow

Rainfall

Open water body ET

Bare soil ET

Superficial in-flow Superficial out-flow

Bedrock

Saprolitic

Aquifer

Saprolitic

discharge

Saprolitic

recharge

Methodology Conceptual model of wetland-scaled water balance

∆𝑆∆ 𝑡

=(𝑃+𝐺𝑊 𝑖𝑛+𝑆𝑊 𝑖𝑛 )− (𝐸𝑇+𝑆𝑊 𝑜𝑢𝑡+𝐺𝑊 𝑜𝑢𝑡 )=0

𝐺𝑊 𝑖𝑛

𝐺𝑊 𝑖𝑛

𝑆𝑊 𝑖𝑛𝑆𝑊 𝑜𝑢𝑡

𝑃

𝐺𝑊 𝑜𝑢𝑡

𝐺𝑊 𝑜𝑢𝑡

[𝑃 ∙𝑋𝑝+𝑆𝑊 𝑖𝑛 ∙𝑋 𝑠𝑤 .𝑖𝑛+𝐺𝑊 𝑖𝑛∙ 𝑋𝐺𝑊 ,𝑖𝑛 ]− [𝑆𝑊 𝑜𝑢𝑡 ∙𝑋 𝑆𝑊 ,𝑜𝑢𝑡+𝐺𝑊 𝑜𝑢𝑡 ∙ 𝑋𝐺𝑊 ,𝑜𝑢𝑡 ]=0

Page 16: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Conceptualising groundwater flow

A

A’

B

B’

Transects of hydrogeological profiles marked on study area sub-catchment

Page 17: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Conceptualising groundwater flow

Page 18: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Conceptualising groundwater flow

Page 19: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Conceptualising groundwater flow

Groundwater equipotential lines and flow in shallow aquifer

Page 20: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Conceptualising groundwater flow

Groundwater equipotential lines and flow in the saprolitic aquifer

Page 21: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Evapotranspiration

Open water body Evapotranspiration

𝐸𝑇=𝐸𝑣𝑎𝑝𝑜𝑟𝑎𝑡𝑖𝑜𝑛 𝑓𝑟𝑜𝑚𝑎𝑛𝑜𝑝𝑒𝑛𝑤𝑎𝑡𝑒𝑟 𝑏𝑜𝑑𝑦

𝐸𝑠𝑎𝑙𝑡=𝐸𝑣𝑎𝑝𝑜𝑟𝑎𝑡𝑖𝑜𝑛𝑟𝑎𝑡𝑒 h𝑤𝑖𝑡 h𝑡 𝑒𝑒𝑓𝑓𝑒𝑐𝑡 𝑜𝑓 𝑇𝐷𝑆𝑖𝑛𝑤𝑎𝑡𝑒𝑟 𝑏𝑜𝑑𝑦

𝐸𝑝𝑎𝑛=𝑃𝑎𝑛 𝐸𝑣𝑎𝑝𝑜𝑟𝑎𝑡𝑖𝑜𝑛

𝐸𝑝𝑎𝑛/𝐸𝑙𝑎𝑘𝑒=𝐸𝑣𝑎𝑝𝑜𝑟𝑎𝑡𝑖𝑜𝑛𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡

𝐴=𝑆𝑢𝑟𝑓𝑎𝑐𝑒𝑎𝑟𝑒𝑎

Where

(Tweeda, Leblanca & Cartwright 2009)

(Marimuthua, Reynoldsa & Salle 2005; Allison 1974; Tweeda, Leblanca & Cartwright 2009)

0.7

Page 22: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Evapotranspiration

Estimating bare soil evapotranspiration - Chen (1992)

Monthly bare soil ET with E1 (0.024 of Epan) and E2 (0.4 of Epan)

J an Feb Mar Apr May J un J ul Aug Sep Oct Nov Dec

Epa n 396.4 357.7 310.5 191.4 121.1 72.8 81.4 97.2 131.2 209.0 281.2 379.4

Mean number

of days of rain

≥1mm

2.0 1.8 2.2 1.5 5.0 6.2 7.5 6.4 5.1 2.6 2.0 1.7

E1 (mm/month) 8.3 7.5 6.4 4.1 2.0 1.0 1.0 1.4 2.1 4.2 5.8 8.1

E2 (mm/month) 20.5 18.4 17.6 7.7 15.6 12.0 15.7 16.1 17.8 14.0 15.0 16.6

mid Feb – beginning June (4 months)

Page 23: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Surface water run-off

• Assumed that surface run-off within the immediate vicinity of W023 and W024

(Groen and Savenije 2006)

J an Feb Mar Apr May J un J ul Aug Sep Oct Nov Dec Annual

Monthly Interception

(Im ) - mm6.8 5.1 7.3 4.4 15.4 17.1 22.1 18.4 14.2 7.4 5.3 5.5 129.1

J an Feb Mar Apr May J un J ul Aug Sep Oct Nov Dec Annual

Surface run-off from

area of 1000 m2

(m3

)

4.5 1.2 4.0 1.3 5.3 3.5 6.0 4.5 3.0 1.7 0.9 2.6 38.6

Page 24: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Methodology Surface water run-off

Possible flow patterns of surface water in-flow (generated using ArcGIS 10.1)

Page 25: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

A

B

D

C

H

E

F

G

W023

W024

Methodology Surface water run-off

A B

DC

H E FG

Elevation profiles across W023 and W024

Page 26: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

 

Methodology Surface water run-off

Estimation of surface area of water body

W etland

H ighes t

s urafce Area

(m2

)

H ighes t water

level (m)

Annual minimum

water level (m)

S urface area at

minimum depth

(m2

)

Average s urface

area (m2

)

W 023 7623.5 1.35 0.70 1475.9 4549.7

W 024 10584.0 0.64 0.00 0.0 5292.0

Page 27: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Volume

(m3

/year)

Cl-

concentration

(mg/L )

Cl- M as s

(kg/year)Comments

P ercentage

of error

2188.7 8.0 17.5 S ection 3.1 and 3.12

1980.0 1036.0 2051.3 S ection 3.9 and 3.12

1048.9 1036.0 1086.7 S ection 3.9 and 3.12

4061.1 8.0 32.5 S ection 3.11 and 3.12

9278.7 3188.0 Total input

1440.0 1825.0 2628.0 S ection 3.9 and 3.12

7930.2 S ection 3.10.1 and 3.12

9370.2 2628.0 Total output

-91.5 m3/year

-12.0 mm/yearB alance560.0 kg/year

Horiz ontal groundwater outflow (GW o u t)

Open water body evapotrans piration (E T)

INP U T

OU TP U T

P recipitation (P )

Horiz ontal groundwater inflow (GW i n )

S urface water inflow (S W i n )

Vertical groundwater inflow (GW i n )

Water and Chloride balance of W023 for a period of 12 months (from Sep 2012 to Sep 2013)

Results Water and Chloride balance of W023

Page 28: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Results Water and Chloride balance of W024

Volume

(m3

/year)

Cl-

concentration

(mg/L )

Cl- M as s

(kg/year)Comments

3116.2 8.0 24.9 S ection 3.1 and 3.12

1055.9 1097.0 1158.3 S ection 3.9 and 3.12

2923.4 8.0 23.4 S ection 3.11 and 3.12

7095.5 1206.7 Total input

789.8 1921.0 1517.1 S ection 3.9 and 3.12

5062.9 S ection 3.10.1 and 3.12

981.2

6833.8 1517.1 Total output

261.7 m3/year

34.3 mm/year-310.5 kg/year B alance

IN P U T

P recipitation (P )

H oriz ontal groundwater inflow (GW i n )

S urface water inflow (S W i n )

B are s oil evaporation (E T)

OU TP U T

H oriz ontal groundwater outflow (GW o u t)

Open water body evapotrans piration (E T)

Water and Chloride balance of W024 for a period of 12 months (from Sep 2012 to Sep 2013)

Page 29: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Results Discussion

Water qualityW 023 W 024

E C (mS /cm) 3.8 to 7.43 0.18 to 7.92

pH 7.49 to 9.08 6.95 to 8.65

R edox potentia l (eh mV) - 97.5 to 205 - 65 to 201

Cl- (mg/L ) 1825 1921

TDS (mg/L ) 3448 4826

Water balance components of W023

Volume

(m3

/year)

Cl-

concentration

(mg/L )

Cl- M as s

(kg/year)

24% 2188.7 8.0 17.5 1%

21% 1980.0 1036.0 2051.3 64%

11% 1048.9 1036.0 1086.7 34%

44% 4061.1 8.0 32.5 1%

9278.7 3188.0

15% 1440.0 1825.0 2628.0

85% 7930.2

9370.2 2628.0

-91.5 m3/year

-12.0 mm/year

IN P U T

OU TP U T

P recipitation (P )

H oriz ontal groundwater inflow (GW i n )

S urface water inflow (S W i n )

Vertical groundwater inflow (GW i n )

560.0 kg/year

H oriz ontal groundwater outflow (GW o u t)

Open water body evapotrans piration (E T)

Page 30: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Page 31: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Page 32: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Results Discussion

Volume

(m3

/year)

Cl-

concentration

(mg/L )

Cl- M as s

(kg/year)

44% 3116.2 8.0 24.9 2%

15% 1055.9 1097.0 1158.3 96%

41% 2923.4 8.0 23.4 2%

7095.5 1206.7

12% 789.8 1921.0 1517.1 100%

74% 5062.9

14% 981.2

6833.8 1517.1

261.7 m3/year

34.3 mm/year

IN P U T

P recipitation (P )

Horiz ontal groundwater inflow (GW i n )

S urface water inflow (S W i n )

B are s oil evaporation (E T)

OU TP U T

Horiz ontal groundwater outflow (GW o u t)

Open water body evapotrans piration (E T)

-310.5 kg/year

Water balance components of W0234

Uncertainty Component Error % Reference

Lake-to-Pan coeff 30% (Tweeda, Leblanca & Cartwright 2009)

Surface area (Surface water, ET) Winter (1981), TBRG - (Australian Bureau of Meteorology 2011)

Precipitation 16% - 26% Winter (1981), TBRG - (Australian Bureau of Meteorology 2011)

Groundwater (Hydraulic conductivity) 40% slug tests in Nabappie subcatchment – Variability in Average

Groundwater (Capture zone – ± 0.5) 10% Statistically

Cl- content in surface water Nabappie catchment 500 to 5000 mg/L Bourke (2011)

Page 33: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Results Conclusion

• Flow-through wetlands • Direct contact with the water table of the surficial aquifer• Can be assumed that both of the wetlands are underlain by a silcrete hardpan• Hydrogeochemically different• Majority of inputs being sourced from groundwater and surface water runoff

components. • Considerable attention should be given to the surface water runoff component

because it may carry a significant amount of solutes to wetland W023 (Winter 1981).

W023 & W024

Page 34: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Results Conclusion

W023

𝑆𝑢𝑝𝑒𝑟𝑓𝑖𝑐𝑖𝑎𝑙𝐺𝑊 𝑖𝑛

𝐷𝑒𝑒𝑝𝐺𝑊 𝑖𝑛

concept is supported by the occurrence of mature perennial vegetation in the northern half of wetland W023

𝐺𝑊 𝑂𝑈𝑇

Page 35: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Results Conclusion

W024

concept is supported by the occurrence of mature perennial vegetation in the north-western part of wetland W024

𝑆𝑢𝑝𝑒𝑟𝑓𝑖𝑐𝑖𝑎𝑙𝐺𝑊 𝑖𝑛

𝐷𝑒𝑒𝑝𝐺𝑊 𝑓𝑙𝑜𝑤

Page 36: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Iso- annual average total dissolved solids (TDS mg/L) curves along AA’

Results Conclusion

Page 37: Hydrogeological assessment of two important wetlands (GDEs) in Hodgson's Wetland suite

The University of Western Australia

Questions