Erosion transects have been established upon a mid-slope of an ancient sand ridge (Tona Station) for the purpose of monitoring current land degradation and to monitor future potential land stabilisation. The location of the erosion transects lay between the Great Darling Anabranch floodplains of Tona and a denuded Belvedere landsystem (see attached map; e.g. ESWTW4 - ENETW4). The denuded area will be revegetated over time, which should give rise to the stabilisation of the Belvedere landsystem. The dimensions of the transects are 500m long by 20m wide and they represent an attempt to monitor both the erosion front and the erosion mouth (see diagram below).

There will be two main monitoring processes conducted along the transects to collect erosion data over the long term, which can be noted as follows;

1. The installation of monitoring pegs at the erosion front and mouth. The location of the pegs will serve as a base point for measurements obtained between the peg and the erosion wall and will also serve as a reference for annual photopoint data collection.
2. Measurement along the transect (at erosion front and mouth) to determine the beginning and the end point of the gully walls over time (see table below).

The following table is an example of a gully monitoring transect data sheet.
NB The start and finish of the gully is determined by it’s location along the transect i.e. start of transect = 0 m and start of first gully = 3.4 m and finish of first gully = 4.2 m. In the example below, two transects have been laid, namely at the erosion front and at the erosion base. Photopoints have been set up at the intersection of the transect and the gully side. Pegs can be installed to create a semi-permanent ground reference point.

Transect no.	Rill/gully base (rocky, gravel, alluvium)	Start Rill (m)	Finish Rill (m)	Rill width (m)	Rill depth (m)	X sect area (sq m)
1a (erosion front)	alluvium	14.6	14.8	0.2	0.2	0.04
1a (erosion mouth)	Gravel & alluvium	13.7	15.3	1.6	0.3	0.48
Cont.
Cont.

Survey participants should follow the relevant monitoring map (see attached Map) and duplicate the following procedure to monitor erosion within the designated area.

Equipment required: (per person)

1. 1 x 30 m measuring reel
2. Clipboard
3. Field Data Sheet
4. 1x erosion recording
5. Pencil/sharpener & eraser
6. Compass
7. GPS
8. Range Pole
9. Marker pen/board
10. Tape

 

1. Start of 500m transect at northern end, which will equal 0m on the datasheet provided.
2. Record the start and finish of the gully (measurement taken from the gully walls; as presented in diagram below).
   Example: Start of Gully= 85.9m, Finish=149.8m for erosion base
3. Undertake this procedure for both transect perimeters i.e. erosion front and erosion mouth.
4. While you are at the location as dictated by the monitoring procedure it would be efficient to set up a ‘peg point’ from which further measurements and photopoints will be taken (see below).

note that the arrows represent the measurement between gully walls.

Establishing ‘peg points’

1. Measure distance from peg to gully wall
2. Record distance
3. Establish photo point- walk 10m out from peg in direct line  and record location with a GPS.
4. Fill out photo point record sheet (use the photopoint datasheet as attached).
5. Repeat for all peg points as the monitoring team see fit (please note that in some locations it will not be necessary to photograph all ‘peg points’ as one frame will probably capture a sufficient picture)

 

Peg Code	Peg to Erosion Edge (m)
ENETW4-ESWTW4 (Western Polygon)
Front3ep	30cm
Front4ep	20cm
ENETE4-ESWTE4 (Eastern Polygon)
Front3wp	18cm
Front4wp	45cm

Example of a table used to record data collected by the ‘peg point’ procedure as described above. Note that each peg needs to be assigned a code so that duplication of measurements does not occur.
Note: It should be noted that over time the distance between the peg and the gully wall will change; It will increase if the gully is stabilizing and decrease if the gully is destabilized.