Hampton Fieldtrip Background Info Terms to use when describing beach environments Backdunes: dunes that sometimes develop behind the foredunes. These may be stabilised by

small shrubs and trees. Backshore: land from high tide up to the coastline Backwash: the movement of water back down the beach to the sea Bay: a sheltered part of a sea or lake formed by a curve in its shoreline Beach: formed by materials brought to the shore by waves in the swash Beach renourishment: the artificial placement of sand on a beach Berm: a ridge of sand on a beach Breakwater: structure built on coasts as part of coastal defence to protect an area from the

effects of weather and longshore drift Coastal waters: the area of seawater adjacent to the coast, including offshore and nearshore

waters Coastline: the extreme landward limit prone to the action of waves Cliff: a steep, rocky slope formed by waves eroding the rock face Constructive waves: waves that carry and deposit sand and other materials Deposition: the laying down of material carried, for example, by waves, ocean currents or wind Destructive waves: large waves that carry sand and other material away in the backwash Erosion: wearing away of the Earth’s surface by agents such as wind, water and human activity Estuary: the tidal mouth of a river where the salt water of the tide meets the fresh water of the

river current Fetch: the distance over which the wind has blown waves Foredunes: sand dunes closest to the beach Groyne: a low wall or sturdy timber barrier built out into the sea from a beach to check erosion

and drifting Headland: land jutting out into the sea, usually at the end of a bay Hinterland: the land adjoining the coast in view of the shore High and low tide mark: the highest or lowest point above sea level that the shoreline reaches

under the influence of tides Intertidal zone: the land between low-tide and high-tide marks Longshore drift: the movement of sand and other materials along a beach Nearshore waters: shallow waters that extend from the surf zone to the shoreline Offshore waters: the deep water seaward of the surf zone Open sea: deeper sea beyond the continental shelf Refraction: the bending of waves caused by their contact with the sea floor and headlands Rip: water flowing out to sea in a strong current Rocky platform: formed by wave action eroding a cliff, leaving a platform of rock behind Sand dunes: dunes that occur when dry sand is blown to the back of a beach and trapped there Shore: the land adjacent to the sea which receives some form of marine influence, including sea

winds or salt spray

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Shoreline: the water’s edge at any particular point in time Swash: the movement of water up the beach after a wave breaks Swell: the movement of the waves

Coastal Processes

Erosion and DepositionCoastal landforms are produced by two major processes – erosion and deposition. Erosion is the wearing away of the Earth’s surface by agents such as wind and water. Wind and waves create the energy that erodes the rocks along coastlines. Waves are constantly striking against a coastline. When the weather is windy, the waves are larger and more powerful. As the waves hit the coastline, the energy in them is used to erode rocks and move sand, pebbles and other material. SWaves carry sand and other material on and off the shore. When a wave breaks, the water from it runs up the beach. This is called the swash. The movement of water back down the beach to the sea is called the backwash. You may have observed the swash and backwash moving sand, shells, seaweed and other material up and down a beach. When storms occur and waves are large, more material is carried in the backwash to deep water. These are called destructive waves. When the waves are small and contain less energy, sand and other materials are more likely to be carried in the swash and laid down as deposits on the beach. These are called constructive waves.

Backwash is stronger that the swash in destructive waves so material is removed the beach. These waves are frequent in number (10 – 15 per minute) and they are tall and powerful.

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Swash is stronger than the backwash in constructive waves causing them to deposit material on the beach. They are less frequent (6 – 9 per minute). Waves are long but no high and roll onto the beach rather than eroding. They create a wide, gently sloping beach.

Longshore DriftIn addition to moving material into and out of beaches, waves move material along the shore.Waves rarely approach a beach at right angles. They usually approach at an angle that depends on the direction of the wind. The swash travels up the beach in the same direction as the breaking wave. Due to gravity, the direction of the backwash and any material it is carrying tends to be straight down the beach, perpendicular to the coastline. The result is that sediment material is transported along the beach in a zigzag movement parallel to the shore. This lateral movement of sediment material along the coastline is called longshore drift and is usually in one direction only – that of the prevailing wind. Longshore drift can be seasonal. When winds blow in a certain direction during one season then change direction during another season, the direction of longshore drift can alter, as occurs in Port Phillip. Over time, long

Hampton Beach is influenced by seasonal longshore drift. In summer at Hampton Beach, sand moves north-west towards Green Point. In winter, sand moves south-east towards Picnic Point.

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A Brief History of Hampton BeachHampton Beach was once part of a continuous strip of sand running from Picnic Point to Green Point, including Brighton Beach. The Hampton Life Saving Club was formed in 1913, to patrol the southern end. However, construction of the boat harbour in the early 1950s trapped sand from the beach and erosion resulted. Beach nourishment was attempted in the 1970s, with little success; and the New Street groyne was built in 1986. This has trapped sand on the northern side and helped Brighton Beach, however Hampton remains virtually a shadow of its former self. Today the 900 m long beach is broad, but stagnant in the boat harbour. It consists of a few patches of sand where the Hampton Life Saving Club was previously located, and only a seawall, rocks and groyne up to the New Street groyne. Hampton Life Saving Club is located opposite the Sandringham Yacht Club between the Small St and New St Groynes. The Beach is well protected with a safe swimming area directly in front of the Life Saving Club. There are a few reefs just north of the club house, but these are easily visible from the shore. The Beach is popular with young families, and increasingly popular with Windsurfers and Kite Surfers.

People flock to beach environments for recreational activities, modifying them to better serve their needs. The effects of these changes are often dramatic and harmful to the natural environment. The solutions are generally costly. Hampton Beach provides an insight into natural coastal processes and how human interference can both degrade a coastal region and also reverse coastal degradation.

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The construction of Sandringham Harbour interfered with longshore drift at Hampton beach. It caused sand to build up in the harbour during winter, posing a threat to boats moored in the marina. It also prevented sand being redistributed to Hampton Beach during the summer, making the beach less attractive to beach-goers.

Severe storm activity in 1934 caused considerable erosion of the beach and damaged yachts andfishing vessels. At the time, it was feared that Beach Road and nearby homes would be damaged.A stone wall was built to protect the road and residential developments from further threats. In the 1950s, a stone breakwater was added to ensure that Sandringham would be a safe harbour and that vessels within would be protected from storm activity. These actions, though well-meaning, were disastrous for the beach environment. The eroding foreshore was previously a vital source of sand for the beach. The interruption of seasonal longshore drift meant that eroded material was moved into the harbour and deposited during winter but could not then move in the reverse direction in summer.

By the 1970s, the beach had completely disappeared. The sea wall was also suffering extreme damage, requiring frequent and costly repair. In addition, constant maintenance was needed to prevent the harbour from being choked by sand. The local community became alarmed at the range of problems facing Hampton Beach. Those with vision realised that careful planning could see the return of this once popular beach. Several studies were undertaken to ensure that the best possible results were achieved. Every effort was made to carefully think through decisions and thoroughly consider all possible environmental impacts. Mistakes caused by quick decision-making and insufficient attention to long-term environmental effects were avoided. The aim was to restore Hampton Beach as a sustainable beach, while taking full account of aspects such as access, traffic, the marine ecosystem, water quality and stormwater management.

Computer simulation was used to consider management alternatives. Two rock anchor groynes were built to protect the beach from the seasonal variations in longshore drift. These groynes also housed stormwater drains within them, which were hidden from public view. Two smaller timber groynes were built to provide extra stability for the beach region. To restore the beach, sand was dredged from a site 350 metres south-west of the Sandringham breakwater. This site was chosen because of its coarse sand, which was more likely to remain in place and not be washed or blown away.

During beach renourishment, approximately 160 000 cubic metres of sand was pumped intospecially constructed compartments along the beach. This meant sand could be directed to theright area. The process began on 15 September 1997 and continued around the clock for ten days.

Today, Hampton Beach has been restored, although its appearance is somewhat different tothat of 100 years ago. The shoreline is protected, and massive revegetation programs were carried out. Ongoing environmental monitoring confirms that the delicate marine environment has not suffered any adverse effects as a result of the works.

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A summary of managementA number of artificial structures have been constructed over the last 150 years to balance the needs of the local population with the sustainability of the coastline. These have included sea walls, groynes, jetties, piers and breakwaters and have been predominantly to control the movement of sand.

1861: the coastline between Green Point and Picnic Point consisted of cliffs 5 to 10 metres high, bordered by a continuous sandy beach up to 30m wide.

1962: the pier shown in the historical photo previously was dismantled 1930: Present sea wall was constructed down to the Hampton Life Saving Club. The cliffs

were landscaped to a stable artificial slope. This stopped the erosion of the cliffs which used to supply the beach with sand and so now stopped the beach from being naturally replenished.

1952: The breakwater at Sandringham Harbour, extending from Picnic Point, was completed. It began to act as a sand trap by excluding the southerly wave action that previously carried sand northward from Picnic Point.

Year after year much of the sand that moved southwards in winter has become trapped on the shore behind the breakwater in the Sandringham Harbour, the primary reasons for the depletion of Hampton Beach.

1972: Stone groynes were constructed, up to 30m long and 50 to 80m apart. These were put in to trap drifting sand and retain the beach.

1986: A groyne was constructed opposite New Street in preparation for beach nourishment using sand dredged from Beaumaris Bay.

1997: Major renourishment of beaches and additional groynes built at Hampton to contain this sand.

2009: Additional renourishment occurred.

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ReferencesBird, E (1987) Geology and Landforms of Beach Park, Sandringham City Council

Chisholm, A et al. (2015) New Perspectives Units 1 & 2, GTAV, Melbourne

Mraz, J (2007) Geography 2, John Wiley & Sons, Milton, QLD

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