Dealing with salinity in Wheatbelt Valleys - Department of Water
Dealing with salinity in Wheatbelt Valleys - Department of Water
Dealing with salinity in Wheatbelt Valleys - Department of Water
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agriculture) <strong>in</strong> various stages, the oldest be<strong>in</strong>g<br />
approximately 85 years ago, while the newest is<br />
25 years. Approximately 80% <strong>of</strong> the landscape has<br />
been cleared for agriculture. The rema<strong>in</strong><strong>in</strong>g remnant<br />
vegetation is <strong>in</strong> the form <strong>of</strong> Conservation<br />
Commission controlled Reserves, vacant Crown land<br />
and Road Reserves, <strong>with</strong> approximately 10%<br />
rema<strong>in</strong><strong>in</strong>g on farms.<br />
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Hydrology <strong>of</strong> the Area<br />
NYABING<br />
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ONGERUP<br />
(<br />
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Detailed hydrological studies <strong>of</strong> the P<strong>in</strong>grup town<br />
catchment through the Rural Towns Programme,<br />
and the M<strong>in</strong>elup Creek Catchment and Range Road<br />
Catchment through the Focus Catchment Process,<br />
have been completed.<br />
A drill<strong>in</strong>g project, which has placed piezometers and<br />
observation wells throughout the catchment, is <strong>in</strong><br />
place. These were drilled <strong>in</strong> 1997 to 1998 and are<br />
NHT funded. Lewis & Nelson (1994) concluded the<br />
follow<strong>in</strong>g about the area’s hydrology:<br />
PINGRUP<br />
Soils<br />
Morrell, Hatton and Curry<br />
The district consists <strong>of</strong> a large bank <strong>of</strong> salt lakes<br />
runn<strong>in</strong>g from south to north <strong>with</strong> slightly undulat<strong>in</strong>g<br />
lands surround<strong>in</strong>g these lakes. Soils vary from very<br />
sandy to heavy clay; all however are relatively<br />
shallow soils over a clay base (Figure 2).<br />
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Figure 2: Lake Ch<strong>in</strong>ocup Soils Map<br />
– 3 –<br />
JERRAMUNGUP<br />
(<br />
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LEGEND<br />
Towns<br />
Roads<br />
Subcatchments<br />
Soils 500k<br />
Loamy duplex<br />
Loamy earth<br />
Rocky or stony soils<br />
Sandy earth<br />
Shallow sandy duplex<br />
Wet soils<br />
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• Average annual recharge under agriculture is <strong>in</strong><br />
the order <strong>of</strong> 5–50 mm. Coarse textured soils<br />
probably contribute most recharge to the<br />
catchment aquifers, but some areas <strong>with</strong> f<strong>in</strong>er<br />
textured soils are likely to be significant, even<br />
<strong>with</strong>out waterlogg<strong>in</strong>g conditions.<br />
• The water table is ris<strong>in</strong>g below many parts <strong>of</strong> the<br />
catchment at rates <strong>of</strong> about 10–30 cm/yr.<br />
• Episodic recharge result<strong>in</strong>g from flood events<br />
may contribute most <strong>of</strong> the recharge occurr<strong>in</strong>g<br />
below some parts <strong>of</strong> the valley floor. Major<br />
summer storms may contribute a significant<br />
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