Causes, impacts, and sustainability issues of dryland salinity on wetlands in Australia

1
Causes, impacts, and sustainability issues of
dryland salinity on wetlands in Australia

• SWES 574
• W. J. Ward
• 12/09/2003

2
(No Transcript)
3
(No Transcript)
4
Mining and Agriculture Anthropogenic Salinisation

• Dryland salinities result from

• Diverted inflows for irrigation and other uses
• Excessive clearance of natural, deep rooted
  vegetation from catchments
• Discharge of saline agricultural wastewater
• Rising saline groundwater
• Mining and discharge of brine waters
• Salinity rising in Mono Lake, CA., Pyramid Lake,
  NV., Aral Sea, Asia, Qinghai Hu, China, Lake
  Qarum, Egypt, Lake Corangamite, AUS. and rivers
  Syr, Amu darya, Asia, Blackwood, AUS.

5
Anthropogenic Salinisation (cont.)

• Salinisation common in semi-arid regions of
  annual rainfall of 25-500 mm
• 43-47 of all irrigated land has been effected
  by salinisation
• Potential to cause irreversible damage to arid
  land rivers and wetlands
• In Australia lost agricultural production is 50
  mil/yr U.S. and degradation of infrastructure is
  an additional 90 mil/yr. U. S.
• Vegetation death is caused by toxic levels of
  bicarbonate, magnesium, sulphate, sodium, and
  chloride
• Loss of species and species diversity
• Waters become unusable for irrigation or drinking

6
Copper Lode Gold Bauxite Tin
Nickel Uranium
Figure 1 Known Mineral Resources
7
Removal of native vegetation causes increased
recharge to groundwater
Water table rises with increased groundwater
mobilization
Saline Seeps
Dry land Crops and Grazing
Low Permeability layer
Hydraulic Pressure and upward groundwater
movements in aquifers
Saline lake size increases as water table rises
Saline soil develops where water table rises to
less than 2 meters from surface
Saline groundwater in drains
Figure 2. Clearing deep rooted vegetation leads
to salinity of rivers and lakes
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
CEC total amount of exchangeable cations that
can be held by a given mass of soil
12
Exchangeable Ca / Na Cation Experiment

• Saturate Arizona White House Bt horizon clay with
  NaCl Cations
• Removed Cl ions by washing
• Mix clay with sand for permeable layer
• Flow solution of CaCl2 through clay/sand
• Remove excess Ca cations and Cl ions by washing
• Extract Ca cations with LaMotte Extraction
  Solution
• Precipitate Ca cations with LaMotte Sodium
  Oxalate
• Compare sample precipitate with LaMotte sample
  strip

13
RESULTS Visually compare test tube results with
PPM chart ? ? ?
Background Ca Na Exchanged 130 mg/L Ca Na
Exchanged in Sat. Ca
14
Figure 3. Dryland Salinity Hazard
Australian rising groundwater salinity sequence
of events dryland salinity hazard mapping using
GIS

• Tree clearing in upper part of catchment
• Winter rains with low evapotranspiration
• Fractured rock deep groundwater aquifer
• Hydraulic head beneath clay floor
• Kaolinite, illite, and semectite in debris-flow
  allows cation-exchange releasing sodium
• Clays decrease hydraulic conductivity under
  saturated conditions

15
Summary

• Early mining timber use and early settlement and
  agriculture land clearing degraded long term
  sustainability
• Increased recharge creates valley area
  groundwater discharge through clay debris flow.
• Discharge cation exchange causes increased
  salinity of surface waters negatively impacting
  lakes and wetlands

16
Summary (cont.)

• Column experiment simulated the cation exchange
  between Ca Na in high CEC clays
• Cation exchange occurring in Yass River
  Catchment, New South Wales, Australia causing
  rising salinity in rivers, lakes, and wetlands
• Mapping salinity and remediation to prevent
  excess infiltration is key to further damage

17

• Reference List
• Blinn, D. W. and Bailey, P. C. E.(2001).
  "Land-use influence on stream water quality and
  diatom communities in Victoria, Australia a
  response to secondary salinization."
  Hydrobiologia , 466(1-3), 231-244.
• Bradd, J. M., Milne-Home, W. A., and Gates,
  G.(1997). "Overview of Factors Leading to Dryland
  Salinity and its Potential Hazard in New South
  Wales, Australia." Hydrogeology Journal, 5(1),
  51-67.
• Davis, J. A. and Froend, R.(1999). "Loss and
  degradation of wetlands in southwestern
  Australia underlying causes, consequences and
  solutions." Wetlands Ecology and Management,
  7(1-2), 13-23.
• George, R., McFarlane, D., and Nulsen, B.(1997).
  "Salinity Threatens the Viability of Agriculture
  and Ecosystems in Western Australia."
  Hydrogeology Journal, 5(1), 6-21.
• Hendricks, D. M. (1985). Arizona Soils, Roswell
  Bookbinding, University of Arizona.
• Jankowski, J. and Acworth, I. R.(1997). "Impact
  of Debris-Flow Deposits on Hydrogeochemical
  Processes and the Developement of Dryland
  Salinity in the Yass River Catchment, New South
  Wales, Australia." Hydrogeology Journal, 5(4),
  71-88.
• Johnson, R. H. and Bush, P. W. (2002). "Summary
  of the Hydrology of the Floridan Aquifer System
  In Florida and In Parts of Georgia, South
  Carolina, and Alabama." USGS Professional Papers,
  1403-I.
• Lemay, T. (2001). "Groundwater Chemistry in the
  Athabasca In Situ Oil Sands Area, Northeast
  Alberta." Rocks Chips, Publication of the Alberta
  Geological Survey, 1-4.
• Markewitz, D., Davidson, E. A., de O. Figueiredo,
  R., Victoria, R. L., and Krusche, A. V. (2001).
  "Control of cation concentrations in stream
  waters by surface soil processes in an Amazonian
  watershed." Nature, 410, 802-805.
• McBride, M. B. (1994). Environmental Chemistry of
  Soils, Oxford.
• Nabhan, G. (1985). Gathering the Desert,
  University of Arizona Press, Tucson, Arizona.
• Rolls, E. C. (1999). "Land of Grass The Loss of
  Australia's Grasslands." Australian Geographical
  Studies, 197.
• Tickell, S. J.(1997). "Mapping Dryland-Salinity
  Hazard, Northern Territory, Australia."
  Hydrogeology Journal, 5(1), 109-117.
• Williams, W. D.(1999). "Salinisation A major
  threat to water resources in the arid and
  semi-arid regions of the world." Lakes
  Reservoirs Research and Management , 4(3-4), 85.
• Williams, W. D.(2001). "Anthropogenic
  salinisation of inland waters." Hydrobiologia,
  466(1-3), 329-337.