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Transcript of Coastal Management
Coral reefs are one of the largest ecosystems on the earth. They are underwater colonies of rock and different organisms that help and feed off of each other to survive.
Coral reefs contain fish, plankton and other organisms.
One of the main organisms in this ecosystem is the polyp. Polyps grow on the coral rock and they have a mouth which allows them to feed on plankton. They are plants so they can photosynthesize and that is how they obtain oxygen and sugar.
They are the producer in a food chain which means they use the sun as a source of energy and they provide energy for all the other organisms in the food chain.
Coral reefs have 3 different formations that they form around volcanic islands; a fringing reef, a barrier reef and an atoll reef.
A fringing reef is when the coral reef is underwater around it is surrounding the island in a circular shape.
A Barrier Reef is when the coral reef is almost out of the water and when the volcanic island has started sinking.
Atoll reefs are completely out of the water and still in a circular shape but the volcanic island is fully submerged into the water. As these formations are being created, the coral reef and the volcanic island are rising and lowering respectively.
There are 2 types of coastal management strategies, hard engineering strategies and soft engineering strategies. Hard engineering strategies are when we build structures or interfere with the natural coastal processes while soft engineering strategies are when we let the natural coastal processes do as they please and not interfere.
Types of hard engineering strategies are:
- Sea walls. They are strong barriers placed parallel to the shore which reflects the sea’s energy away and prevents erosion.
- Groynes. They are walls built 90 degrees to the shore which aim to slow down LSD and trap sediment.
- Rip-Rap. They are large boulders lined up across the shore.
- Gabions. They are steel wire baskets filled with rock.
- Revetments. They are wooden slatted barriers.
- Offshore reefs. They are enormous concrete and natural blocks that are sunk offshore to alter the wave direction.
A type of soft engineering strategy is:
- Manage Retreat. This is when areas of coast are allowed to erode and the natural processes are allowed to occur. This usually happens in areas where land is of low value, so heavily protecting it would be a waste of money.
Erosion is the opposite of deposition.
It is when strong waves collide with the shore and break down the shore by taking all the material and sand with it.
It makes the shore shorter which makes it less useable to different people.
This happens because of something called a backwash, which is the movement the wave does as it is retreating into the ocean. Backwash’s can be strong or weak.
A strong backwash takes back a lot of material from the beach so it destroys the beach and it is caused by a high wave height and a short wave length. A weak backwash barely takes any material from the beach but it also builds up the beach. Waves that have a strong backwash are called destructive waves and waves that have a weak backwash are called constructive waves.
Erosion can take place in many different forms. Abrasion is when the waves carry rocks in it and when the wave collides with the shore, the rocks crash into the shore which breaks pieces off that get taken by the wave. These are some of the many types of erosion. Corrosion is when the water in the waves have a bit of acidity in them, so they break pieces of the shore off when the wave collides. Finally Hydraulic pressure is when air or water gets trapped in the rocks or shore, which causes an increasing pressure in the trapped substance which leads the rocks and shore to crack.
The Coast is a part of the land that joins with the sea. It is a place where lots of activity happens due to its value to many people such as fishers, tourists, exporters, importers...
The problem however, is that the coast needs to be managed properly in order for the coast to prevent erosion from occurring. With erosion on the coasts less people want the land and so the land becomes of less value. This is wasted space for what could have been an opportunity for more economic income through means such as tourism, trade, oil, or fishing. In the following presentation, we will be talking about the coast, its dangers and prevention methods
Rashid and Zein
Deposition is when there is material being transported by a flow or stream of water until it gets deposited.
The process of deposition occurs when a stream if water loses energy when it enters a shallow area of water or towards the mouth where it meets another body of water such as the sea
The area where rivers flood is called the floodplain
After many floods sediment starts to form around the floodplain
A large majority of deposition occurs next to river channels. This is due to increased friction with the floodplain
Sediment builds up and creates a ridge higher than before next to the river channels on both banks of the river and is called a leeve.