| 
Following
the two community meetings in early July, researchers at the GCCM began an investigation
into options for improved wave quality at Kirra.  Background
As
many of you know, both on top of and under the water, Kirra has changed remarkably
over the past 10 years. In the 12 months prior to the removal of a section of
Big Groyne in 1996, Stage 1A of the Tweed River Estuary Sand Bypassing Project
(TRESBP) delivered approximately 2,300,000m3 of sand to the beaches and nearshore
zone of Coolangatta Bay with the specific focus of ‘re-establishing depleted
upper beach and nearshore sand levels’ (Boswood 2001).
In
April 1995 1,500,000 m3 of sand was placed in the nearshore zone in the 6-10m
depth range. In May, 600,000 m3 was placed on the upper beaches; and in the 5
months following this, a further 200,000 m3 was placed in the nearshore zone in
the 0-5m depth range (remember an olympic pool contains 2,500m3 of sand). This
dredging campaign moved almost 50% of the total volume of sand that has been dredged
to date. The TRESBP dredging campaign, combined with the removal of part of the
groyne in 1996 led to a large and sudden change to the structure of the bay (filling
in holes, smoothing the bay floor, raising the seabed height etc). This program
of works succeeded in the objective of creating a wider beach but had the effect
of significantly altering wave quality. Further information on the TRESBP dredging
and
pumping programs are available on the TRESBP website:
www.tweedsandbypass.nsw.gov.au  Current
considerations
The volume of sand in Coolangatta Bay and specifically in
the area around Big Groyne and Kirra Reef is significant. Since the bypass operations
commenced in March 2001, the annual average of sand pumped (to March 2006) has
been 681,909m3, with a maximum amount of 755,072m3 pumped in the year ended March
2004.
Prior to the
bypass operations commencing, 3,580,067m3 of sand was dredged from the Tweed
River.
The annual average of sand dredged from April 2001 – April 2006 has been
292,438m3 with a maximum amount of 498,898m3 in 2001-02 and a minimum amount of
169,926m3 in 2004-05. The average annual rate of sand deposited (dredged + pumped)
since the bypass commenced operations is 974,596m3. These figures have been taken
from the TRESBP
website. At
the August 2006 Advisory Committee meeting for the TRESBP, the community was informed
that the project will now deliver a volume of sand closer to the identified ‘natural’
littoral drift of
500,000m3 per year, and we can expect to see a downscaling
of the dredging operations over the next few years. The
purpose of the Griffith University project is to present a series of options to
the local community on how surfing amenity might be improved. Any recommendations
made by the community need to be considered against the expected condition of
the bay in a few years time, the time it might take for an intervention to have
any effect and the possible economic, management and liability considerations
around these issues.  Gold
Coast Shoreline Management Review Information Sheet - October 2006
The
range of opinions from the community meetings on this issue in July can be summarised
into 5 options. These are:
1. Modifications to Big Groyne.
2. Supplementary
outlet to the north.
3. Extend the ‘grid system’ for dredged sand
to be placed further to the north.
4. Realign the beach profile at Kirra.
5.
TRESBP operates according to current management plans. Note:
While options are being investigated independently, GCCM recognises that combinations
of options are possible and may ultimately be the preferred strategy. 1.
Modifications to Big Groyne.
This option involves investigating the benefit
of:
* Extending Big Groyne back to the pre-1996 length
* Extending Big Groyne
by 50m
* Removing Big Groyne 2.
Supplementary outlet to the north.
This option involves investigating the
benefit of creating a supplementary outlet in the North
Kirra / Bilinga area. 3.
Extend the ‘grid system’ for dredged sand to be placed further to the
north.
This option involves investigating the benefit of extending the
grid system further to the north,
which will enable the dredge to dump sand
further along the coast. 4.
Realign the beach profile at Kirra.
This option involves investigating
a number of options that may assist in realigning the beach
and sandbank profile
at Kirra. These options include:
* Beach scraping
* The creation of a ‘lagoon’
type system that may encourage the shoreline and sandbank
to migrate shorewards
at an angle 5. TRESBP
operates according to current management plans.
The TRESBP has put forward
a position statement suggesting the typical conditions that we may expect at Duranbah
and Coolangatta Bay, including Kirra, in 3 years time. They are as
follows:
•
Duranbah Beach to be similar to now – i.e. it would need to be nourished
once or twice a
year. Snapper Rocks to provide good consistent surfing, but
not provide the long rides of the early 2000s.
• Rainbow Bay to be similar
to now – i.e. variable and not as wide as in the early 2000s.
• Greenmount
Beach will also be variable. Typically it is expected to recede up to 30-
50m
at the Greenmount Headland end with some separation of surfing breaks between
Snapper
Rocks and Greenmount.
• Coolangatta Beach (closer to the Kirra Point groyne)
to be similar to now, but with smaller
inner nearshore shoals.
• Kirra
Beach to recede about 100m to near the end of the Miles Street Groyne.
•
Kirra Point to become more prominent, and “point break” surfing conditions
to become
more frequent.
• Kirra Reef to be significantly larger –
about 3,000 square metres in area.
(Information provided by Ian Taylor Project
Manager, Tweed River Entrance Sand Bypassing Project on 11/08/06) Timeline
We
expect to have the modelling completed in November. Other surf related projects
currently underway on the Gold Coast
• Investigation into the placement
of safe surfing signs (Council and Surfing Qld).
• Investigation into
the declaration of surfing reserves at Burleigh and Kirra/Snapper (Council and
the National Reference Group).
• Report into the value of recreational
surfing on the Gold Coast (Council and Griffith Centre
for Coastal Management).
•
Law / Lore of the Surf Forum scheduled for November 2006 (TBC).
• Video
documentary on surfers, surfing and coastal processes at Kirra and Coolangatta
Bay.
We are currently seeking sponsors to assist with the completion of this project.
If
you are able to make a contribution, please contact us on the details below. More
Information
Project Manager: Neil Lazarow
Griffith Centre for Coastal Management
Griffith
University Gold Coast Campus
PMB 50 Gold Coast Mail Centre 9726
P: (07)
5552 8389
P: (07) 5552 8506 (Secretary)
M: 0416 022 742
F: (07) 5552
8067
E: n.lazarow@griffith.edu.au
W: www.griffith.edu.au/centre/gccm/gcsm | 
