SELECTED HYDROGRAPHS FROM KEY SALINITY BORES IN THE BALLARAT SUB-REGION
PITTONG
Groundwater Trend Up date
PITTONG
Granite Rises
’94
GROUNDWATER HYDROGRAPHS
A graph of groundwater levels against time is usually refered to as a
hydrograph. The pattern of water level variation in a hydrograph is dependent
upon the nature of the groundwater system. As well as indicating long term
trends, the hydrograph often also fluctuates according to the seasons. A peak
is commonly observed in winter/spring as a result of recharge during this
period. Where there is minimal seasonal fluctuation, only minor recharge to the
watertable is suggested, though soil waterlogging or excess run-off may then be
significant issues.
’96
’97
’98
’8 9
-2
’99
’91
’9 2
’93
’94
’9 5
’9 6
’97
’98
’85
’9 9
’ 95
’96
’97
’9 8
Depth to water (m)
Depth to water (m)
-12
-4
’9 7
Over all s teady conditions . No noticeable
impact as ye t fr om up-s lope tr e e block.
Ver y slight r is ing wate r table te ndency that could
indicate long term gr oundwat er accumulati on
-4
-5
Strong seasonal fluctuations i ndicate high r echarge.
Hint of overall rise i n wate rtable. Reduct ion in
monitor ing frequency mak es i nter pr etati on difficult
PITTONG
Granite Rises
’9 0
’91
’92
’9 3
’9 4
’95
’96
’9 7
’98
’99
Ballarat
De p th to w a te r (m )
66622(23)
5290
119367 47192
Skipton
BALLARAT
-5
’97
’98
5155 Grenville
GRENVILLE
’89
Moder ate fall in w ater table likely to be
caused by lower than average rai nfall from
the mid-1990s
’93
’94
’9 5
’96
’97
’98
’92
’93
’94
’95
’96
’97
De pth to wa ter (m )
Sus tained falling water table that could be linked
to plantation es tablis hment in t he Gr envill e ar ea
Cressy
LINTON
’89
Ver y slight fal ling water table since 1993
c oinciding wi th below average r ainfall
LISMORE
’9 3
’9 4
’95
’96
’9 7
’98
’89
’99
Basalt Plains
’90
’91
’92
’93
’94
’95
’96
’97
’98
CRESSY
-3
Bore No. 4405 lower slo pe
-5
-6
D ep th to w ate r (m )
-2
-10
-11
’92
’9 3
’94
’9 5
’96
’9 7
’98
Western Highland Hills
’90
’9 1
’9 2
’93
’94
’95
’96
’97
’9 8
’99
PPDQQ XDOUDLQIDOO
500
100
-100
’8 5
-1
-12
Depth to water (m)
Western Highland Hills
’89
’91
’93
’95
’97
-2
-3
’94
-2
’9 5
’9 6
Western Highland Hil ls
’97
’98
’99
Bore No. 286
-3
-4
-5
-4
Slight fall in water table. Little or no direct
r echar ge i ndicated her e, though s easonal
pe rched w ater table smay be si gnificant
ROKEWOOD DEMO. FARM
’99
Bore No. 26662
Bore No. 92658
126
Slight r is ing water table, probably due to lateral
gr oundwater accumulation r ather than di rect
r echar ge
-5
Over all dr op in water table indicated des pite
missing data
’87
Shallow groundwate r conditi ons indic ated on
edge of Bas alt Plains near R okewood.
-300
-500
-6
ROKEWOOD
’99
127
Bore No. 4406 mid-slope
Slight fall ing wate r tables s ince the mid 1990s
coinciding wi th below ave rage r ainfall
’91
128
-7
-9
Basalt Plains
’90
129
Bore No. 4420
-1
’89
’99
-9
0
Depth to water (m)
Basal t Plains
’92
ROKEWOOD
-4
Depth to water (m)
-13
Height of water abov e s ealevel (m)
Depth to water (m)
LAND MANAGEMENT UNITS
The key bores here overlay Land Management Units (LMUs). LMUs are
zones of similar geology, soils, landscape type and climate. By definition, a
particular LMU would be expected to respond in a consistent manner with
respect to salinity treatment
-12
’91
200
0
-200
-400
-3
’99
Bore No. 5151
’9 0
PP DQQXDO UDLQIDOO
600
400
300
-11
LISMORE
SKIPTON
-6
92658
Bore No. 261
Depth to water (m)
’99
-5
-10
-8
’98
Bore No. 515 5
-4
G ranite Rises/Basalt Plains
’92
PP
DQQ
XDOUDLQIDOO
400
200
0
-200
-400
-600
-8
92659
-6
’91
LISMORE
-7
64139
’9 0
’91
-3
-4
LISMORE
’90
Western Highland Hills
-2
96050 4420
44064405 Lismore
-5
’99
-11
26662(63)
Rokewood
’99
-3
’98
Despite low r ainfall period, s light r ising
watertable that indicates the pos s ibility of long
term gr oundwater accumul ation.
5411
5410
5412
2865414
261
-2
’9 7
Bore No. 5268
Bore No. 5141
-1
’96
-10
Granite Rises
’96
’9 5
-12
Slight r is ing tende ncy until 1997 be fore a
s tep- down i n the w atert able
’9 5
Granite Rises
’94
-9
97869
’94
PPDQQXDOUDLQIDOO
700
500
300
100
-100
-300
-4
-4
’93
99’
PITTONG
2905263
Lint on
5148
Linton
5145
5267
5268
5141 5151
5271
’9 2
98’
Over all s teady, though onl y monitor ed since
1995.
-3
’ 91
97’
-6
-2
’90
96’
Bore No. 5290
Bore No. 5145
PITTONG
95’
-3
NRE / Co mmunity managed bore
SKM managed bore
Water bodies
Outside study area
Ballarat Land Mana gement Units
Basalt plains
Cropped basalt rises
Granite ri ses
Wester n highland hills
Soutern upl and hil ls
Alluvial plai n
Lake & dune system
Stoney rise s
Scoria hil ls
Dissected plains
Sand & clay rises
Clay plains
-1
-4
KEY BORES
18 representative or key bore sites have been selected
across the Ballarat sub-region of the Corangamite
Dryland Salinity Region to assist in the analysis and
reporting of groundwater trends. These have been
selected on the basis of representative trends within a
monitoring network, geographic distribution, quality and
length of record. Trends from the key bores are reported
on a 2 yearly basis.
Western Highland Hills
94’
-25
’89
’9 9
-6
-5
-13
Depth to water (m)
-24
Gr adual fall in w ater table that coincides with a
period of lower rainfall .
Depth to water (m)
’9 5
Bore No. 66622
-3
LEGEND
-26
Depth to water (m)
’9 3
HADDON
Bore no. 290
’89
’91
’99
-23
’89
0
’89
Bore No. 5148
-11
G ranite Rises
’94
’89
Basalt Plains
’87
-3
Bore No. 5263
Depth to water (m)
HADDON
Granite Rises
’90
Rainfall Tre nds Sinc e 198 0
PITTONG
Depth to water (m)
’95
-10
Litt le change indicated her e to date, des pite
establ ished tr ee belts and per ennial past ure
RAINFALL GRAPHS
The bar graphs in the above rainfall charts indicate deviation
of annual rainfall from the long term average for each
station. The accompanying line graphs indicate the
cumulative deviation. Interestingly, the cumulative deviation
across much of south-eastern Australia has been rising since
the mid-1940s. Since 1982, the cumulative deviation for the
stations above has generally been rising or at least remained
steady, before dropping with the onset of a relatively dry
period post-1993 (e.g. Skipton and Lismore). However
rainfall patterns can significantly alter over short distances,
such as the different patterns exhibited at Ballarat and
Rokewood.