Groundwater Monitoring within the Kamarooka Project

Groundwater monitoring is conducted at monthly intervals within the Kamarooka Project area.  The main focus is on recording changes in the depth of the watertable over time in response to both treatments and climate.  The results from this work to date are presented below. :   

Kamarooka Project Groundwater Monitoring Program

Height of casing above ground level

1.07

1.04

1.09

1.07

1.02

1.03

1.04

1.03 1.05 1.05

Date

 

Bore 1

Bore 2

Bore 3

Bore 4

Bore 5

Bore 6

Bore 7

Bore 8

Bore 9

Bore 10

3/10/2004

DTC*

4.41

2.3

2.07

1.73

1.6

1.66

1.88

n/c* n/c* n/c*

3/10/2004

DTW*

3.34

1.26

0.98

0.66

0.58

0.63

0.84

n/c* n/c* n/c*

27/11/2004

DTC*

3.14

1.97

1.85

1.65

1.67

1.66

1.74

n/c* n/c* n/c*

27/11/2004

DTW*

2.07

0.93

0.76

0.58

0.65

0.63

0.7

n/c* n/c* n/c*

26/12/04

DTC*

3.07

2.24

2.08

1.77

1.76

1.77

1.82

n/c* n/c* n/c*

26/12/04

DTW*

2.0

1.20

0.99

0.70

0.74

0.74

0.78

n/c* n/c* n/c*
          Bores 8, 9 & 10 constructed on 19/20 Jan 2005
22/01/05 DTC* 3.44 2.53 2.35 1.98 1.94 1.97 2.00 2.25 5.85 2.12
22/01/05 DTW* 2.37 1.49 1.26 0.91 0.92 0.94 0.96 1.22 4.8 1.07

Special thanks to East Loddon College for monitoring the bores on 11 March 2005

11/03/05 DTC* 3.20 2.40 2.28 1.96 1.90 1.92 2.00 2.20 5.87 2.08
11/03/05 DTW* 2.13 1.36 1.19 0.89 0.88 0.89 0.96 1.17 4.82 1.03
17/04/05 DTC* 3.70 2.78 2.6 2.27 2.19 2.21 2.21 2.4 5.85 N/M
17/04/05 DTW* 2.63 1.74 1.51 1.2 1.17 1.18 1.17 1.37 4.8 N/M

Note:  Monitoring on 22/5/05 falls one week after bores were bailed for chemical analysis

22/5/05 DTC* 5.06 3.12 2.95 2.55 2.45 2.47 2.45 2.61 7.1 2.6
22/5/05 DTW* 3.99 2.08 1.86 1.48 1.43 1.44 1.41 1.58 6.05 1.55
27/06/05 DTC* 4.34 3.03 2.69 2.12 1.97 2.10 2.10 2.50 6.95 2.10
27/06/05 DTW* 3.27 1.99 1.6 1.05 0.95 1.07 1.06 1.47 5.9 1.05
17/07/05 DTC* 3.98 2.84 2.59 2.14 1.93 2.05 2.13 2.44 6.95 2.21
17/07/05 DTW* 2.91 1.8 1.5 1.07 0.91 1.02 1.09 1.41 5.9 1.16
21/08/05 DTC* 3.81 2.87 2.65 2.22 2 2.1 2.3 2.46 6.96 2.31
21/08/05 DTW* 2.74 1.83 1.56 1.15 0.98 1.07 1.19 1.43 5.91 1.26
24/09/05 DTC* 3.94 2.93 2.71 2.3 2.06 2.16 2.35 2.3 7.5 2.38
24/09/05 DTW* 2.87 1.89 1.62 1.23 1.04 1.13 1.31 1.27 6.45 1.33
24/10/05 DTC* 3.7 2.76 2.42 1.89 1.43 1.6 1.64 1.83 7.50 1.66
24/10/05 DTW* 2.63 1.72 1.33 0.82 0.41 0.57 0.60 0.80 6.45 0.61
21/11/05 DTC* 2.78 2.28 2.05 1.77 1.73 1.75 1.78 1.87 7.15 1.85
21/11/05 DTW* 1.71 1.24 0.96 0.70 0.71 0.72 0.74 0.84 6.1 0.80
4/01/06 DTC* 3.39 2.75 2.54 2.19 2.08 2.1 2.16 2.33 7.1 2.38
4/01/06 DTW* 2.32 1.71 1.45 1.12 1.06 1.07 1.12 1.3 6.05 1.33
19/01/06 DTC* 3.68 2.94 2.73 2.39 2.25 2.26 2.3 2.48 7.25 2.58
19/01/06 DTW* 2.61 1.9 1.64 1.32 1.23 1.23 1.26 1.45 6.2 1.53
19/02/06 DTC* 4.02 3.18 3.00 2.62 2.43 2.45 2.50 2.70 7.25 2.82
19/02/06 DTW* 2.95 2.14 1.91 1.55 1.41 1.42 1.46 1.67 6.2 1.77
21/03/06 DTC* 4.32 3.47 3.29 2.91 2.74 2.68 2.8 3.04 7.45 3.1
21/03/06 DTW* 3.25 2.43 2.22 1.84 1.72 1.65 1.76 2.01 6.4 2.05
2//04/06 DTC*     3.35 2.99 2.81 2.78 2.90 3.15   3.22
2/04/06 DTW*     2.26 1.92 1.79 1.75 1.86 2.12   2.17
23/04/06 DTC* 4.6 3.64 3.49 3.14 2.97 2.91 3.1 3.35 dry 3.4
23/04/06 DTW* 3.53 2.6 2.4 2.07 1.95 1.88 2.06 2.32 dry 2.35
20/05/06 DTC* 4.79 3.73 3.6 3.2 3.09 3.03 3.22 3.49 7.55 2.65
20/05/06 DTW* 3.72 2.69 2.51 2.13 2.07 2.0 2.18 2.46 6.5 2.45
18/06/06 DTC* 4.94 3.82 3.67 3.29 3.15 3.32 3.30 3.63 7.35 3.63
18/08/06 DTW* 3.87 2.78 2.58 2.22 2.13 2.29 2.26 2.6 6.3 2.58
26/09/06 DTC* 4.7 3.18 2.96 2.55 2.3 2.33 2.55 2.8 7.15 2.88
26/09/06 DTW* 3.63 2.14 1.87 1.48 1.28 1.3 1.51 1.77 6.1 1.83
24/10/06 DTC* 4.76 3.3 3.1 2.72 2.53 2.52 2.72 2.97 7.25 3.18
24/10/06 DTW* 3.69 2.26 2.01 1.65 1.51 1.48 1.68 1.94 6.2 2.13
17/12/2006 DTC* 4.98 3.8 3.6 3.2 3.13 2.98 3.35 3.65 7.55 3.85
17/12/2006 DTW* 3.91 2.76 2.51 2.13 2.11 1.95 2.31 2.62 6.5 2.8

Note: Bores are numbered from 1 through 10 beginning in the SE corner of the trial

n/c = not constructed

*DTC = Depth to watertable from top of casing

*DTW = Depth to watertable from soil surface

Each observation well is located along a traverse extending from a small area of relict native vegetation in the southeast corner (bore 1) of the trial through the more saline land into to the northwest region (bore 7). 

Seven wells are located at approximately one hundred metre intervals. They are designed to monitor the impacts of each treatment on watertable depth and salinity over time as the vegetation (halophytes, trees, and native grasses) mature.

There are plans to extend the monitoring through the establishment of an additional three wells to enable better assessment of the impact of native vegetation (both existing and recently planted) along the northern extremities of the trial area.  

What do the numbers mean?  

When high salinity groundwater present at Kamarooka rises within 1.6 metres of the land surface it is drawn upward by capillary action and causes extreme salinity.  Information realised from the observation bores (above) indicates this condition occurs throughout almost all of the project area.   

Six of the seven observation wells (2,3,4,5,6 & 7) reveal a watertable less than this critical depth 
(1.6 metres).  Five bores (3,4,5,6,7) indicate a watertable shallower than 1.0 metres. The project area is ,thus, for the most part a zone of very active saline groundwater discharge.  

Dramatic variations in the appearance and extent of soil salinity result from small variations in micro-relief and the presence or absence of topsoil (the 'A' horizon).  The most severe salinity occurs where the watertable is shallow in areas where topsoil has been removed by wind erosion (deflation).  Areas where the topsoil has not removed by erosion are subject to sufficient seasonal leaching to sustain salt levels low enough to maintain salt tolerant native vegetation.  The sub-soils of these regions, however, are equally as saline as those within areas severely affected by salinity.   

The entire project with the possible exception of a slightly more elevated region in the southeast corner supporting native vegetation is subject to saline groundwater discharge.  Variation in the manifestation of salinity across the site area are easily explained by the presence or absence of topsoil, and subtle variations in micro-relief.

Beyond a depth of some thirty centimetres the same saline conditions occur within all clay sub-soils of the project area. Treatments, thus, should recognise this condition and be designed accordingly.

Data Loggers monitor shallow groundwater

By December 2004 it was apparent that the groundwater beneath remnant native vegetation in the south-eastern sector of the project areas was much deeper than anticipated.  It seemed that the trees were using saline groundwater and maintaining the watertable at a depth of two to three metres. 

During January 2005 additional groundwater observation wells were installed to complete a line of bores stretching throughout the area.  Each bore was strategically located to record future watertable fluctuations beneath each treatment.  Another observation well was established to monitor remnant vegetation (old Grey Box trees). This time within a stand present on the northern extremities of the trial.

Groundwater under the northern stand of remnant vegetation proved to be even deeper than had been recorded under the southern stand. The watertable was almost five metres below the land surface in a region  not more than fifty metres from the main saline land where groundwater was present at a depth of less than one metre.

It was immediately clear from these observations that a more intensive monitoring program would be required to ascertain interactions between vegetation and groundwater.  Accordingly the NUFG took the decision to invest in two electronic water level loggers and an electronic barometric pressure logger in order to gain greater insight into groundwater responses under different treatments. The barometric logger was purchased to correct water level (bore) logger readings for changes in atmospheric pressure.  

The data loggers were installed in late March 2005.  One logger was placed in a bore the midst of the saline land where the watertable was within one metre of the land surface, and the other was placed in the bore monitoring remnant vegetation to the north of the trial site.

The loggers were set to record the depth of the watertable every ten minutes.  This high intensity data recording was aimed at understanding whether the watertable was moving up and down in response to daily fluctuations in evaporation and transpiration. 

The data collected to date (presented below) demonstrates a linear fall in the watertable beneath the saline land.  It is clear this is occurring in response to evaporation from the capillary fringe.  It is anticipated that this decline will continue until the depth to the watertable reaches about 1.5 metres from the soil surface.

The groundwater trend under the remnant vegetation is in strong contract with that under the saline land.  Here the watertable is maintained at a constant level of about 4.8 metres from the soil surface.  

Both graphs illustrate very strong, almost identical responses to diurnal changes in light and temperature.  It is becoming clear that these represent daily variations in both evaporation and transpiration.

Hydrograph illustrating watertable responses 
under saline land and remnant vegetation

Results from data loggers (27 June 2005)

Watertable beneath saline land (September 2005)

Watertable Fluctuations (All bores Manual Records November 2005) 

Watertables Fluctuations Saline Land (Manual Records November 2005) 

Watertables Fluctuations Saline land (Data Logger November 2005)

Watertables Remnant Vegetation (Data Logger November 2005) 

Watertable Fluctuations Kamarooka (Manual Records February 2006)

Watertable Fluctuations (Manual Records March 2006) 

Watertable Fluctuations (Manual Records April 2006)

Watertable Fluctuations (Manual Records May 2006)

Daily Rainfall May 2006

Watertable Fluctuations (Manual Records June 2006)

Watertable fluctuations October 2006

Watertable fluctuations December 2 2006

Watertable fluctuations December 17 2006

Watertable fluctuations May 22 May 2006 All bores

Watertable fluctuations May 22 May 2006 Selected bores 1

Watertable fluctuations May 22 May 2006 Selected bores 2

Watertable fluctuations June 24 2007 All Bores

Watertable fluctuations June 24 2007 Selected Bores

Watertable depth fluctuations July 2007

Watertable elevation July 2007

Watertable fluctuations August 2007

Watertable elevation August 2007

September 2007 Manual/Datalogger records 

Watertable elevation (Manual) bores 1 - 10

Remnant vegetation (south) bore 1 logger

Saltland bore 5 logger

NUFG plantation bore 8 logger 

NCCMA/NUFG biodiversity trial bore 10 logger

Roadside north of NUFG plantation bore CO70 logger 

Upper Catchment Hogg's Road bore CO72 logger 

October 2007 manual monitoring