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Discover natural methods like dune building and beach replenishment to combat beach erosion and protect coastal habitats. Learn about the benefits of vegetation and fencing in stabilizing dunes and how beach nourishment can restore eroded beaches.
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Slide: 1 Natural Approaches to Solving the Beach Erosion Problem • Dune Building • Beach Replenishment
Erosion Solution: Dunes Dunes are hills built by water flow Habitat for flora and fauna Protect from erosion and encourage deposition Slide: 2
Slide: 3 Dune building can be done using natural means or it can be done using man made structures. Natural: planting vegetation Man Made Structures: using sand fencing
Slide: 4 Dune building method #1 Use of Vegetation Sand dune stabilization: Sand dune stabilization is a coastalmanagement technique for preventing erosion. Sand dunes trap sand and beach material that is washed up or blown up to the shore. The rate of erosion is slowed and an effective flood barrier is created. Footpaths will also have to be introduced to stop trampling. Sand dune stabilization is economical, environmentally friendly, does not disrupt the coastline further on, creates natural habitats for animals and plants and is not regarded as unattractive. However, for successful dunes to be placed it must be thoroughly researched beforehand and will take a long time to establish. Sand dunes may be stabilized through the planting of vegetation. Vegetation encourages dune growth by trapping and stabilizing blown sand.
Slide: 5 It is clear to see that people have tried to help save the dunes in this area by planting vegetation
Slide: 6 The plant life here, has helped to capture the blowing sand.
Slide: 7 The shore side of the dune…
Slide: 8 This picture shows the leeward (land) side of the dune. Write a claim about the amount of vegetation on the windward (ocean) side of the dune. Support with reasoning.
Slide: 9 Inland → ←Shore Look at the vegetation that is nearest the shore. Compare it to the vegetation that is further inland.
Slide: 10 How does vegetation help to save the beaches?
Slide: 11 These diagrams show how the natural action of the waves helps to restore eroded beaches. This occurs in a natural cycle.
Slide: 12 Dune Building Solution #2: Temporary Fences • Standard slatted wood sand fencing is ideal for dune-building structures because it is inexpensive, readily available, easy to handle, and can be erected quickly.
Slide: 15 Plastic fencing has the advantage of being strong, durable, and reusable, and it won't be taken for campfire fuel. Plastic fencing, however, is about three times as expensive as wooden sand fencing.
Slide: 16 Keep our beach areas beautiful! For aesthetic reasons, for safety, and to avoid interference with public access, dune-building structures should be removed as soon as they have served their purpose. Sand collected by structures should be stabilized with appropriate vegetation.
Slide: 17 Keeping pedestrians off the dunes !! Elevated walkovers can prevent damage to dunes from pedestrian traffic. If walkovers are conveniently placed near access roads, parking areas, beachfront subdivisions, and public facilities, pedestrians will be less likely to cut foot paths through the dunes to the beach. The presence of walkovers may increase public awareness of the value and fragility of sand dunes.
Slide: 18 Solution:Beach Replenishment More than 70% of Earth's shorelines are retreating due to rising sea levels. As shorelines move landward, structures located on or near the beach may be destroyed. In addition, communities may lose significant amounts of income if they lose the use of their beaches. It is, in fact, the interaction of the natural migration of the beach with the placement of beachfront structures creates the demand for shoreline protection. If no homes, roads or businesses were built in the coastal area, beach retreat might be seen more as the fundamental process that it is and not as a threat that should be corrected. Shorelines moving landward do not necessarily mean that beaches will vanish.
Slide: 19 Beach nourishment: A beach is the perfect defense against waveaction and, if a beach is poor, one option may be to undertake beach nourishment. This basically involves adding large quantities of material to a beach in order to build it up. The material added will need to be very similar to the material naturally found on the beach. Offshore dredging can provide a good source of suitable material for beach nourishment. This involves importing sand off the beach and piling it on top of the existing sand. The imported sand must be of a similar quality to the existing beach material so it can integrate with the natural processes occurring there, without causing any adverse effects. This barge is taking the sand from further out in the ocean and shooting it onto the beach. This is called dredging.
Slide: 20 The barge that is dredging in this picture is shown far out in the ocean. The pipes on the beach carry the sand from the barge to the beach.
Slide: 21 Here, the sand is deposited on the beach from the pipeline.
Slide: 22 Another picture of beach replenishment from dredging.
Slide: 23 Bulldozers are then used to spread the sand around the newly restored beaches.
Slide: 24 Let’s examine how erosion and deposition have played an important role in creating a beach that you may be familiar with.
Slide: 25 This is Sandy Hook New Jersey. It was created by the act of deposition. Sand from the south is brought to the north by a current known as the Longshore Current.
Slide: 26 Longshore Current North South As the Longshore Current is moving northward, the ocean tides and waves pull the sand to the beach. These actions sometimes work against each other. Sand is therefore deposited in many new places as it moves along the shoreline.
Slide: 27 Notice how the water current and waves stir up the water and carries it along to a new place depending on the direction the current is flowing. You may have felt the effects of a current while standing on the shoreline. It pulls you farther north or south without you realizing it.
Slide: 28 Sandy Hook New Jersey The shape of Sandy Hook is also due to the actions of people to try and restore the southern beaches from erosion. Notice the V shaped extensions of beach on the eastern shore line.
Slide: 29 Sandy Hook beach was once a sand bar that formed into a peninsula by a northern flowing current called the long shore current. As the current pulls sand from southern areas of the New Jersey shoreline, it deposits the sand at Sandy Hook in the north. Now that Sandy Hook is a peninsula, it still feels the effects of the long shore current. The southern beaches of Sandy Hook erode a bit each year while the northern beach continues to grow. Let’s examine the process of erosion that is occurring on the southern beaches and ways that this can be fixed.
Slide: 30 Solution: Groins and seawalls can be used to help restore the beaches.
Slide: 31 Groins, or jetties as they are sometimes known, are often made of rock, wood or concrete. They are placed perpendicular to the beach to catch sand as it travels north.
Erosion Solution: Groins Groins are structures that interrupt water flow and limit erosion Slide: 32
Slide: 33 Examine the picture of Sandy hook again. Why do you think the beach has this V shaped formation on the eastern shoreline?
Erosion Solution: Sea Walls A sea wall is a wall that is built along the beach Absorbs no water Completely prevents both deposition and erosion Slide: 34
Slide: 35 Sea walls A seawall is a structure which is designed to protect a shoreline from flooding and erosion. Essentially, a seawall acts as a layer between the vulnerable coastline and the ocean. Wave action can beat at the seawall without eroding the coast, although the seawall itself will eventually break down and require repair or replacement. Seawalls also help to insulate communities from flooding, although high waves can still rise over most seawalls. A seawall can also provide a space for recreation, since the top of a seawall is often flat, allowing people to walk on it or to fish from it.
Run for the hills! More storms are on the way. What will happen to our beaches?
