7.8 Dune Revegation at Stuarts Point - Questions

1. Name and locate the coastal dune management area discussed in this unit.
The area discussed in this unit is Stuarts Point. Stuarts Point is located at the mouth of the Macleay River just south of Grassy Head headland and North of Shark Island and South West Rocks. 


2. Using the material in the unit, construct a timeline that highlights the changes in the Stuarts Point sand dune ecosystem. 
1893 - A large flood opened up a gap for the Macleay River at South West Rocks causing the original mouth of the Macleay River to close due to build up of silt and lessen in flow. 
Early 1900's - The gap closed allowing cattle to graze along the dune barrier system. Eventually the vegetation was lost and on three consecutive occasions of heavy storms the dunes were drowned. The idea of the dunes being lost caused action from the community as there was threat against some property.
1965 - After approaching the Soil Conservation Service of New South Wales for advice and assistance, they provided native plant seedlings to what was going to be the start of the revegetation program for Stuarts Point. Unfortunately, this scheme failed in August due to cattle grazing. 
1970 - With all the organisations working together, they developed a scheme that would re-establish the dunes in three parts. They would have a primary dune consisting of grasses and creepers, a secondary species consisting of shrubs and short-lived trees and a tertiary species consisting of long-lived trees. 
Today - It continues to be a success today with the plan still intact and very few issues. 


3. Describe the role of the local community in managing the sand dune area.
The community had a large role in making the management of the sand dunes successful. They had the responsibility to keep on the walking tracks, keep litter to a minimum and some people from the communities even volunteered.  Their involvement was a key area of the re-establishment of Stuarts Point. 


4. Why is the sand dune area important to the people of Stuarts Point?
The dune area is very important to the the people of Stuarts Point. Without it, some properties would be lost making it almost crucial to have the dunes in place. 


5. Using 7.35 describe the natural vegetation succession on sand dunes.
The sand dunes are built up of three separate and different plant types.  The first section being made up of grasses and creepers that trap dry sand in the frontal dunes and reduce the sand and spray onto dunes behind it. The second section is made up of  shrubs and short lived trees that are highly adapted prolific re-seeders, fast-growing plants. Finally the third section is made up of long-lived trees that are permanent, highly interdependent, surviving in protection of dune and secondary species. 


6. Explain why vegetation is so important in stabilising sand dunes. 
Vegetation is important in stabilising sand dunes as it stops the wind from blowing the sand away and keeps the sand firm from being washed away by long shore transportation. 


7. What impact did cattle grazing have on the sand dune area?
Cattle grazing meant that the vegetation was lost and therefore the were no longer any plants to keep it firm/strong. 


8. Describe the changes to the sand dune area that would have occurred after cattle grazing. Identify the geographical processes that would have been altered as a result of the removal of vegetation from the dunes. 
The sand dune would have become less dense or firm and there would be great loss of sand due the the natural process of long shore transportation. 


9. Identify the groups involved in the rehabilitation program.
The groups involved in the rehabilitation of the sand dune were the Department of Lands, the Department of Public Works, the Macleay Shire Council and he Soil Conservation Service of New South Wales. 


10. Outline the stages involved in the management program undertaken to re-establish the coastal vegetation. 
The stages taken to re-establish the coastal vegetation included; using a tractor to form a small foredune, then they planted trees along the river band, then they planted the native seedlings between the foredune and the river band and finally once the plants were established coastal tertiary species. 


12. Use maps to explain the geographical process that would have caused the river mouth to silt up. 
The geographical processes that would have caused the Macleay River to silt up include; long shore transportation from the southern parts of the beach as well as wave refraction because the beach faces east. 


13. Evaluate the success of the revegation program in the following areas:
a) Stabilising the sand dunes. The stabilising of sand dunes through revegetation was an enormous success as the sand dunes are still standing strong. By using a multi-part system they made a successful stabilised dune. 
b) Protecting the Macleay River ecosystem. The success of protecting the Macleay River ecosystem was very true, they managed to replant native bushes and trees without causing harm to the dune system. They only issue was that Bitou Bush, a toxic weed that spread all of the fore and hind dunes. 
c) Benefiting groups from the local community. The community benefited immensely from this project. They now had a clear pathway which occasionally needs maintenance and a sand barrier to protect some properties. 


14. (power point presentation)

The TRESB Project

1. The problem which lead to the TRESB Project

The problem that lead to the TRESB project was that the entrance to the Tweed River had become a hazard to shipping due to the build up of sandbars in the river mouth. Various attempts to fix the problem such as breakwaters and frequent dredging became uneconomical and impractical. The breakwaters created sand build up and the periodical sand dredging of the river mouth became to expensive. Therefore this lead up to the creation of the TRESB project. 

2. The solution to the problem. 

The solution to the problem came with the cooperation of the state government and local council with the community. The Tweed River Entrance Sand Bypassing Project became one of the most successful examples of how people can implement management schemes that replicate natural processes. They replicated the process of long shore transportation in removing sand from a jetty and moving it up the coast to beaches for sand replenishment. 

3. The result of the project. What areas were effected and how? Do you think that it was a success?

The TRESB project became the most successful coastal management strategy implemented in Australia. By bypassing the mouth of the Tweed River, the build up of sand and silt in the river mouth lessened and became wider creating zero hazards for shipping. The whole of Tweed Heads and Coolangatta was affected by this as they created a way of replenishing the sand of beaches in the area. People of Tweed Heads had to sacrifice the aesthetics of having a sand pumping jetty for a wide, deep and clean river mouth. The scheme was the most successful project implemented in Australia. I think it has been a great success for Australian coasts and could lead to much more in coastal development. 

Coastal Management - The Tweed River Entrance Sand Bypassing Project

QUESTIONS - 
1. It became necessary to extend the Tweed River breakwaters because it became a hazard to shipping due to the sandbars that were forming across the river mouth. 


2. The impact of construction to the breakwaters meant that the river had to be periodically dredged of sand. The sand that was dredged was then taken to the Gold Coast where it was used for beach nourishment. 


3. The Tweed River became unsafe to shipping due to the continual sand build up that was occurring in the river mouth. The long term effects of long-shore transportation was also not accounted for. 


4. The dredging of Tweed River was a short term solution as it was expensive and had to occur on a continual basis in order to create a safe entrance to the Tweed River. 


5. TRESBP replicates long-shore drift by pumping sand from where it accumulates on the southern side of the Tweed River, via a system of popes, across the Tweed River to one of the four outlets where sand is released onto the beach. 


6. The Tweed River Entrance Sand Bypassing Project (TRESBP) is a smart alternative to the build up of silt in the Tweed River Mouth. It creates a replacement to the coastal process of long-shore drift or transportation. The solution is simple and effective with the idea that it measures which beach needs the sand the most and places the pumped sand there. I do question whether going to all the effort is necessary. The sand pumping jetty could be considered an eyesore and the sand next to it is rarely replenished. A smart solution to this eye sore could be to add a board walk on top of the jetty, allowing leisurely activities for residents of the area. This makes it both practical and aesthetically pleasing. 


7. 

8.  Since 1962, very big changes have occurred to the mouth of the Tweed River. The river mouth has expanded and from the aerial view looks a lot deeper due to its colouring. In 1962, majority of the sand can be seen spilling into the river mouth compared to 1994 where the sand spillage is controlled and the river mouth is far deeper. 


9. In 1962 the break water was approximately 100metres long where as in 1994 it was around 500 metres. 

Big Wave Profile

1. Design a blog post on your blog of Maverick waves from different parts of the world. Be sure to describe the geography and the topography of the ocean floor in these areas and how this helps create these massive waves.

          Hout Bay as seen from Suther's Peek, (Hout Bay is on the right)

Hout Bay, (Dutch for Wood Bay) is a small suburb within Cape Town South Africa. Hout bay, also known as Dungeons to the surfing community annually hosts the Red Bull Big Wave Africa competition, boasting waves of up to  100ft or 30 metres. 

Annual Red Bull Big Wave Africa Competition, finals 2008

Hout Bay consists of various reefs with different waves styles and sizes. The most popular of all reefs is known as '2.5' because it is 2.5 metres deep with a reef 3.5 metres deep called '3.5'. 

The reasons for the large waves are The Dungeons Reef is the first sea bottom that the ocean swells hit on their path shore wards. These swells, generated across the South Atlantic Ocean, hit the Dungeon Reefs and rear up into these giant right hand breaking waves for brave souls to attempt to ride.

A world map showing (A) where Hout Bay is located.

The huge waves that are produced at Hout Bay are due to interacting High and Low pressure systems within the Antarctic Region. Hout Bay is the first shoreline hit by the waves that produce and grow through the Southern Ocean and the South Atlantic Ocean. The waves that end up being produced with the right wind conditions are clean due to the reef below the water as well as the depth of the water. 

Besides the enormous waves that are produced in Hout Bay, surfers also have to compete with the ice-cold water, the thick kelp beds that cover the inside waters, and the abundant sea life, including a few local sharks that prey on the seal colony.

The Science of Big Waves

Pre-viewing:

1. Where do ocean waves come from? What gets them started? Ocean waves come from out of sea and are caused by wind currents, ocean currents, moon gravitational pull and sometimes mini-earthquakes. 
2. What do you think a surfer should know about waves before they try and ride a wave while surfing? The surfer should understand the science of the waves and how they are formed and what causes them to do things. 

Question for the Video:

1. Observe all the waves that you see and describe how they form and break. Use as many words found in the segment for you descriptions. They begin in the North Pacific (the gulf of Alaska) and are caused by the wind and the water mixing together. They are made of wind speed, fetch and duration.
2. Describe how waves are formed, how they originate, and how they are measured?  Height, period and wavelength are the terms used for the measurement of waves. They are formed by the mix of High and Low pressure systems. 
3. What is a maverick wave and what is special about the way it is formed? The wavelength becomes larger as well as the period between each wave. A Maverick is a large wave that is formed in the gulfs of Alaska. The wave crosses the deep water, crosses the tip of the reef then it encounters rocks and refracts into converging waves. 
4. How is energy stored and transferred during wave? The energy circulates within the wave and the energy is stored as potential energy until it hits the reef and the potential energy surges up into kinetic energy. 
5. List any kind of advice given by the surfers about how to survive these “big waves.” Staying alive is the most important factor when being dumped by waves that can shake the tectonic plates. Get in there quickly before the wave crashes. 

7.3 Geographical Processes

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7.2 Waves - Water on the Move