Wambo Coal AEMR 2011-2012 - Peabody Energy

Sections
Stoney Creek sections scores also ranged from excellent in the upper reaches of the
creek line to good and moderate along the lower more disturbed parts of the creek line.
Excellent scores resulted from an increased number of ground cover species, the
presence of a litter layer and an absence of feral animal species. Three of the four
sections along Stoney Creek recorded minor levels of erosion.
4.2.4 Overall Riparian Condition
The overall condition of the riparian sites based on average calculations is moderate and
good condition. Stoney Creek is identified as being in good condition while both North
Wambo Creek and South Wambo Creek are in moderate condition.
4.2.5 Annual Riparian Condition Photographs
In 2011 four photographs were taken at each riparian transect, with individual
photographs showing the left bank, right bank, upstream channel and downstream
channel. Appendix G shows the photographs from the 2011 riparian condition
assessment. Riparian condition photographs during previous years were varied in their
location, typically showing areas of problem erosion.
4.3 Discussion
Both South Wambo and North Wambo creeks are historically deeply eroded creek lines,
up to four to five metres deep in some parts. Stoney Creek is a shallow narrow creek in
the upper sections and a wide and historically deeply eroded creek in the lower parts.
Past land management practices (presumably land clearing during European settlement)
have resulted in all three creeks being present as deeply eroded channels. Today all three
are essentially grass covered channels with scattered or remnant tree cover and some
areas of minor or moderate erosion.
All three creeks contain some scattered areas of active erosion typically present as
eroding or collapsing banks. These areas of erosion and collapsing banks do not appear
to be a result of current land management practices however there is little evidence of
current land management practices to reduce or eliminate the erosion that is occurring.
Where possible, remedial works to repair eroded banks or tree planting to help stabilise
banks, should be undertaken.
Two common causes for reductions in condition scores were the presence of weeds and
the presence of rabbits. Selective spraying of Lycium ferocissimum (African Boxthorn) and
Olea europaea subspecies cuspidata (African Olive) had been undertaken extensively
throughout 2011. However, these species are continuing to germinate and spread
throughout the riparian areas. In addition, a large percentage of the ground cover
vegetation is composed of introduced exotic species. While these species appear to be
outcompeting native ground cover species, they provide protection for the soil from
erosion and should only be removed when successional native species are planted and
have become established.
2011 Annual Ecological Monitoring Report, Final Report, May 2012 Page 35