Flood-tide delta morphodynamics and shoreline implications in Port Stephens

It has been a while since the last update in February 2009 and I am now back from maternity leave although I am only working two days a week. During my leave, Dr Javier Benavente and Dr Laura del Rio visited the Geocoastal Group at the University of Sydney and worked on the Port Stephens project. Dr Javier Benavente worked with Dan Harris on Shoal Bay morphodynamics and Dr Laura del Rio contributed to GIS analyses.

Dan Harris is currently finalising his Honours thesis and preparing a poster to be presented at the NSW Coastal Conference. Tim Austin has gone forward in his analysis of the ADCP data and is currently starting the analysis of the ADCP transects across the entrance. Wenping Jiang’s modelling is also showing good progress with the Hydrodynamic and Wave modules of MIKE21 (DHI Water and Environment) already set and running. Tim and I presented our results at the International Coastal Symposium in Lisbon (Portugal) in April 2009, we also wrote two papers that were published in the Journal of Coastal Research. Wenping presented her work in Coasts and Ports in Wellington (New Zealand).

We held a progress meeting at the University of Sydney on the 22nd of September. The meeting was a great opportunity for all Chief Investigators of the project to present their results to our partners and to discuss the morphodynamics of the system; I have included a new section about the meeting with links to the presentations. The meeting was a success and we all agreed that the most challenging aspect of the research lie ahead in linking all the studies that we have been undertaking over the past two years. To facilitate this linkage of data and results over the final year we intend to undertake the following measurements providing the opportunity to compare and contrast with our initial data collected: (1) more ADCP transects; (2) some bathymetric measurements over the shoals; and, (3) some more monitoring of the evolution of Winda Woppa.

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Nov-2007	Dec-2007	Feb-2008	Mar-2008	Jun-2008	Nov-2008	Feb-2009

This research project (LP0668979) is funded by the Australian Research Council (ARC) and aims to investigate flood-tide delta morphodynamics and their relationship with estuarine beaches. Management scenarios and climate change implications will also be investigated.

PARTNERS:

• The University of Sydney- School of Geosciences
• The University of Sydney- School of Civil Engineering
• NSW Department of Environment and Climate Change (DECC)
• Port Stephens Council
• Great Lakes Council
• Jimmy's Beach Restoration Society Inc.
• DHI Water and Environment

Port Stephens is a ria-like estuary located 230 km north of Sydney (NSW, Australia). It has an east-west orientation with a total length of 23 km. The shallow nature of the estuary has prevented further development as a commercial/industrial harbour. At present it is one of the most popular tourist destinations on the 1,000 km long NSW coastline.

Fieldwork

The fieldwork campaign involves bathymetric and topographic measurements of the flood-tide delta and estuarine beaches, as well as measurements of waves, tides and currents within the bay and around the shorelines.

Flood tide delta:

• Bathymetric surveys (undertaken by DECC).
• Eulerian and lagrangian current measurements using bottom-mounted and boat-towed ADCPs (Acoustic Doppler Current Profiler) respectively.
• Sediment characterisation.

Estuarine beaches:

• Periodic topographic surveys of estuarine beaches.
• Hydrodynamic measurements (waves and currents) under winter and summer conditions.
• Sediment characterisation.

GIS

Historic photos and maps are being included in a Geographic Information System using ARC-GIS that allows accurate quantification of the evolution of the system.

Modelling

Numerical model is being undertaken using MIKE21 (DHI) to evaluate different management options and climate change scenarios.

This research involves scientists and engineers from The University of Sydney and the NSW Department of Environment and Climate Change. The main researchers from The University of Sydney, School of Geosciences, are Dr Ana Vila-Concejo, Prof Andy Short and Dr Michael Hughes and Prof Dong Jeng from the School of Civil Engineering. David Mitchell and Graham Lloyd, also from the School of Geosciences, provide technical expertise in the operation of field equipment.

Two postgraduate students are undertaking PhD theses within the project: Wenping Jiang and Tim Austin. Three Honours theses have already been completed (Michelle Frolich, Lara Ainley and Gen Pezzimenti, see list of publications below) and further honours students will undertake other projects in the near future.

The NSW Department of Environment and Climate Change provides the expertise of Dr Rosh Ranasinghe and David Hanslow.

Date	Objectives
24.03.2007 27.03.2007	Jimmy's Beach topography, hydrodynamics and sediments
25.05.2007	Shoal Bay topography
26.05.2007	Jimmy's beach topography
19.06.2007 22.06.2007	Jimmy's beach topography and hydrodynamics under strong southerly and westerly conditions
23.07.2007	Jimmy's beach topography and sediments. RTK-DGPS surveying of benchmarks
24.07.2007	Shoal Bay topography. RTK-DGPS surveying of benchmarks
11.10.2007	Shoal Bay topography
12.10.2007	Jimmy's beach topography (rain)
27.11.2007	Lagrangian ADCP measurements (problem with boat's alternator)
28.11.2007	ADCP deployments
29.11.2007	Jimmy's beach topography
30.11.2007	Shoal Bay topography
19.12.2007 20.12.2007	ADCP recovery, download, service and redeployment
14.02.2008	ADCP recovery, download, service and redeployment
15.02.2008	Topography of Jimmy's beach and Shoal Bay
27.03.2008 10.04.2008	Intensive fieldwork in Jimmy's beach including several days of simultaneous hydrodynamic measurements along the beach and detailed topographic surveys.
28.03.2008	Recovey of both ADCPs
10.04.2008	Deployment of ADCP off Fly Point
05.05.2008	Recovery of ADCP- no deployment.
16.05.2008	Fourth failed attempt to measure the cross-sections. Topography of Shoal Bay
17.05.2008	Deployment of both ADCPs
26.06.2008 27.06.2008	Failed attempt to ADCP servicing
20.07.2008 25.07.2008	Winter intensive field campaing at Shoal Bay beach. Detailed topography and hydrodynamic measurements. Failed attempts to ADCP servicing
10.10.2008	Recovery and redeployment of one ADCP Topography Shoal Bay beach
28.10.2008	Topography Jimmy's beach
27.11.2008 28.11.2008	Search for ADCP with DSTO AUV. Possible identification of ADCP in side-scan image
03.12.2008	Search for ADCP with divers
13.12.2008 19.12.2008	Shoal Bay Summer Campaign: Nearshore Hydrodynamics Topography Recovery of ADCP Lagrangian transects at the entrance

These photos show hydrodynamic measurements in Jimmy's Beach (top to bottom and left to right).

• March 2007, everything is set for our first measurements... nice and sunny (we had a southerly on the next day).
• June 2007 erosion in Jimmy's beach after strong southerly. See below for photos during southerly conditions.
• June 2007 measuring during westerly conditions... it was hard to stay warm and dry because we had to get in the water often to clean the instruments.
• June 2007 measuring during westerly conditions... cold, windy and full of weed!
• March 2007 during a southerly.
• Set up of the laptops inside the Blue Box.

These two images show one of our instruments (ADP) covered in barnacles just after being recovered (above); the same instrument is deployed by University of Sydney divers Heather Sowden and Dave Cummings (below). The instrument has been cleaned and serviced.

High energy southerly conditions represent a hazard in Jimmy's beach. We discovered this, after deploying our instruments on the day that the photos were taken. Fortunately we did not lose any instruments, but the POD (mounting bracket for the instruments) broke and we had to leave it behind.

The first four photos show how reflected waves collide with approaching waves producing clapotis. This spectacular process commonly occurs on reflective beaches (such as Jimmys Beach), which are characterised by steep gradients. These photos are taken from the road which is 2-3 m above the beach. The photos in the last row show the beach after the high energy southerly and Tim giving the final touches to the new POD that we had to improvise to continue measuring during the following days.

Here are some of the photos we took during Jimmy's Beach intensive fieldwork in March/April 2008 (top to bottom and left to right):

• Some of the team members, from left to right: Brad Morris, Dave Mitchell, Tim Austin, Mike Kinsela, Alex Frolich, Ana Vila-Concejo, Rhi McKeon, Gen Pezzimenti, Wenping Jiang. They are not in the photo but also participated: Mitch Harley, Michael Hughes, Michelle Frolich and Jess Morgan.
• Instruments deployed on Site 1, east from the sandwave: Dobie wave gauge (borrowed from Rob Brander) and two pods with ADVs and self-logging pressure transducers (borrowed from Tom Baldock).
• It was dark during many deployements, Gen is writing down all the details about the instruments- Brad and Tim got in the water to deploy almost every day!
• Dave making sure that everything is working before deploying.
• Brad and Tim got lucky that day... there was light and it was sunny during the deployment!
• Gen observing the waves and currents and taking notes for her thesis.

Below are some photos from our last campaign, the summer fieldwork in Shoal Bay in December 2008 (top to bottom and left to right):

• Part of the team, this is the day we were heading back to Sydney: Arjen Overduin, Dan Harris, Amy Haughton, Gen Pezzimenti, Mike Kinsela, Rhi McKeon, Dave Mitchell, Tim Austin and Ana Vila-Concejo.
• The topography warriors, Amy and Dan, having their first fights with setting up the RTK-GNSS base station.
• Arjen and Mike moving one of the instruments- great summer conditions for fieldwork!
• The entrance at Port Stephens, where Tim and Mike finally managed to measure cross-sectional transects of velocities.
• Shoal Bay beach, looking north from Station 3.
• Marco and Dan (not) enjoying the day of bad weather that we had to endure.

These results are preliminary and are the subject of ongoing research. I will be adding more figures and results as we get them ready.

This photo shows the evolution of Winda Woppa since 1951 (red), to 1986 (yellow and black), 2001 (pink), 2006 (photo) and 2008 (dotted line).

The figure below shows the locations where we have deployed our instruments so far. We will keep updating this photo as we recover the data from the instruments.

Here are some examples of profile evolution in Jimmy's beach between March and November 2007. The figure below shows the location of the profiles along the beach.

The image below (left) shows the volumetric evolution of Jimmy's beach between March 2007 and April 2008. Engineering nourishment works were undertaken during Winter 2008, sand was dredged from the sandwave and placed on the most eroded areas of Jimmy's beach. The image on the right shows the volumetric evolution between March 2007 and October 2008.

Some of Wenping's modelling results using MIKE 21 (DHI Water and Environment) are shown in the images below: ebbing (left) and flooding (right).

The progress meeting took place in the School of Geosciences and we had representatives from all partners involved in the project.

 

Sydney University	DHI Water and Environment
Prof. Andy Short	Mr Craig Allery
Ass.Prof. Peter Cowell	Port Stephens Council
Dr Michael Hughes	Mr Bryce Cameron
Dr Ana Vila-Concejo	Great Lakes Council
Mr Tim Austin	Mr Andrew Staniland
Ms Wenping Jiang	Jimmy's Beach Restoration Society
Mr Dan Harris	Mr Robert Yuen
NSW DECCW	Mr Brian Oakley
Dr Rosh Ranasinghe	Mr Robert Brell
Dr Alan Jordan	Ms Kit Streamer
Mr Phil Watson

During the day we had a series of presentations about the different research branches of the project and we finished with a discussion session where the way to link all results was discussed. The meeting was steered by Prof. Andy Short. The handout with the schedule and the presentations are freely available (Please cite the source if you use this information, if you have any doubts about how to cite it just contact ).

 

Schedule (PDF)

10:30h: Welcome coffee/tea.

11:00h: Project overview (PDF).

11:30h: Measurements on the Flood Tide delta (PDF).

12:00h: Numerical modelling in Port Stephens (PDF).

12:30h: Shoal Bay evolution (PDF).

13:00h: Jimmy's Beach evolution (PDF).

13:30h: Lunch

14:00h: Discussion and closure.

• Harris, D, Benavente, J, Austin, T, Vila-Concejo, A (2009). Multi-scale morphodynamic assessment of an embayed low-energy estuarine beach, Shoal Bay, Port Stephens, NSW. Proceedings of NSW Coastal Conference.
• Jiang, AW, Allery, C, Vila-Concejo, A, Cowell, P, Ranasinghe, R ( 2009). Dominant hydrodynamic processes at Jimmy’s beach, Port Stephens, Australia: A numerical modelling study. Coasts and Ports.
• Vila-Concejo, A, Short, AD, Hughes, MG, Ranasinghe, R (2009). Formation and evolution of a sandwave on an estuarine beach. Journal of Coastal Research, SI(56):153-157.
• Austin, TP, Short, AD, Hughes, MG, Ranasinghe, R, Vila-Concejo, A (2009). Tidal hydrodynamics of a micro-tidal, wave dominated flood-tide delta: Port Stephens, Australia. Journal of Coastal Research.
• Vila-Concejo, A, Hughes, MG, Short, AD, Ranasinghe, R (in review). Estuarine shoreline processes in a dynamic low-energy system. Ocean Dynamics.
• Pezzimenti, GMC (2008) Tide and wave-induced longshore transport on a low energy estuarine beach within a tide-dominated estuary: Port Stephens, NSW. Honours Thesis, School of Geosciences, The University of Sydney, 81pp.
• Vila-Concejo, A., Hughes, M.G., Short, A.D., Ranasinghe, R. (2008) Estuarine shoreline processes:a dynamic low-energy system. Extended abstract submitted to PECS, Liverpool (UK), 2008 [PDF]. [Download the poster]
• Austin, T., Hughes, M.G., Ranasinghe,R.,Short, A.D., Vila-Concejo, A. (2008) Short- to medium-term flood-tide delta morphodynamics and implications for shoreline management. Abstract submitted to Coast to Coast Conference, Darwin (Australia), 2008 [PDF].
• Ainley, L. (2007) Sediment Transport on Jimmy's Beach: Implications for Coastal Erosion. Honours Thesis, School of Geosciences, The University of Sydney, 80pp.
• Frolich, M (2007) Recent Morphological Evolution of the Port Stephens Flood-Tide Delta. Honours Thesis, School of Geosciences, The University of Sydney, 110pp.
• Vila-Concejo, A, Short, AD, Hughes, MG, Ranasinghe, R (2007) Flood-tide delta morphodynamics and management implications, Port Stephens, Australia. Journal of Coastal Research, SI(50), 705-709. [PDF]
• Vila-Concejo, A, Short, AD, Hughes, MG, Ranasinghe, R (2007). Shoreline implications of flood-tide delta morphodynamics. The case of Port Stephens (SE Australia). Proceedings of Coastal Sediments 2007.