Tuesday, July 13, 2010

Hard Engineering, Disadvantages! :D

Hello once again! :D Now for Hard Engineering's disadvantages! :D

No matter how effective/efficient an appliance/structure may be, it will still have it's flaws and that's normal cause nothing is perfect! :)

Seawalls (Hard Engineering)



Seawalls are made to prevent erosion of the coasts, however, a seawall may not protect a coast from erosion in the long run. This is because, when the waves break against the seawall, the energy from the waves is redirected downwards/to the sides of the seawalls resulting in a strong backwash which wears away base/side of the seawall and causing it to weaken and thus, eventually, it will collapse. Hence, seawalls have to be carefully and constantly maintained.


Furthermore, Seawalls are expensive to built! They are estimated to cost 1 million pound(S$3 million) to build a one kilometer stretch of seawall in England.

Groynes (Hard Engineering)


Groyne is a low wall built at right angles to prevent materials from being transported away by the longshore drift as it interrupts water flow and limits the movement of sediments

The disadvantage for groynes is that on the other side of the groyne, the beach will not be replenished by materials carried by the longshore drift thus, the beach further down the coast may erode away. This can lead to cliff collapse and plummeting house prices and destruction of private land in the region making it difficult for affected homeowners to move out.

Also, no matter how useful a series of groynes is to help reduce the effect of coastal erosion, they still spoil the natural beauty of the coastal environment.


Gabions (Hard Engineering)


Gabions, as we all already know is a wire cage containing small rocks to form a wall to protect the coast against erosion and also other coastal structures. However, theses gabions can be easily destroyed by powerful waves that occur during storms. Also, the wires of the cage can rust easily thus, they are easily destroyed.



Furthermore, gabions too destroy the natural beauty of the coastal environment they may take up quite a lot of space up on the beach as lots of gabions are needed to provide plenty of protection. Also, the rocks inside the cage would become worn down and the whole cage would be needed to be taken out and replaced. Plus, if the gabions are stacked up in a wall and a lower one needs replacing this will mean taking out all the ones above it as well before replacing it and rebuilding the wall. this would take lots of time and money! OH, and they have a short lifespan of less then 15 years only! NOT GOOOOD! :(



Okay so that's all the disadvantages of Hard Engineering for coastal protection measures! Soft Engineering would be written by Rosma! :) so stay tuned for her post! :)

Nous aimons la Géographie;
Diyanah
HELLO . (:

hahaha , aunty here to post about soft engineering which involves the application of knowledge of natural processes to stabilise the coast and reduce erosion. Let me break the down into :


1 . Stabilising coastal dunes ( Sand dune stabilisation )

through planting of vegetation which are tolerant to salt spray, strong winds and sand burial. Sand dunes trap sediments washed and blown up, hence slowing the rate of erosion and creating an effective barrier for flood. Footpaths are created so that people won't trample on the vegetation.

Advantages :
  • does not disrupt coastline
  • creates natural habitats for living things
  • not regarded as unattrative
Disadvantages :
  • must be thoroughly researched beforehan therefore it will take long periods of time until established

2. Beach Nourishment

The process where sediment lost through erosion for example is replaced on a beach. Nourishment material is transported to the affected area.

Disadvantages :

  • expensive
  • (coastal defense scheme) therefore , poorly dedigned project can result in a severely impacted ecosystem regardless of the maintanance.
  • have to be regularly renourish since nourished beaches tend to erode fater than natural beaches.

Advantages :

  • reduces storm damage. During storms with elevated water levels and high waves, a wide beach performs as an effective energy absorber with the wave energy dissipated across the surf zone and wide beach rather than impacting on the upland structures and infrastructure
  • Recreational benifits . In many coastal areas, the recreational benefits of a wide beach can lifestyle benefits for residents, additional public open space and improved fishing, diving and surfing conditions.


3. Encouraging growth of coral reefs

Coral reefs are actually made of animals! Coral reefs provide protection for harbors and beaches, which are often found behind reefs because the reefs provide natural protection from heavy wave action caused by coastal storms.

4. Planting of mangroves

Its long and curved roots trap sediments and reduce erosion. However, not all coastal regions can support mangroves and coasts may become shallower thus affecting port activities.


Okay , that's just the brief summary ! For more information , we found a web for you where you can understand better about this topic :D , www.slideshare.net/vickikoh/coastal-management-4 . Please watch the video . thank you !

goodnight!



Nous aimons la Géographie; Rosma .

Hard Engineering, Advantages! :D

Hello lovelies! Since i did not really elaborate about the importance of Coastal Protection Measure in my previous post, i shall do it now! :)

Coastal Protection Measures are important because there are some cities, such as Brisbane, Houston and many more which are located along the coast and it is estimated that about 3.6 billion people in the world live along that coast! That's a lot! Also, coasts are awesome locations as tourist attractions! However, as we all know, the coast may sometimes erode thus, affecting people who live near coast they they may need to retreat inland and also affect the infrastructure that has been built. Hence, it is important for us to find way to prevent erosion from occurring :)

There are two different types of measures that could be taken. One, Hard Engineering, and two, Soft Engineering. Hard Engineering refers to the construction of structures such as seawalls, breakwaters, groynes and gabions to protect the coast from erosion while soft engineering involves the application of knowledge of natural processes to stabilize the coast and reduce the erosion.

I will talk more about Hard Engineering in this post :)

Seawall (Hard Engineering)


Seawalls constructed on the inland part of a coast to reduce the effects of strong waves. They are usually made out of concrete, boulders, steel or gabions which absorbs the energy of the waters and protects the coast against strong waves, especially during storms. Also, more modern seawalls tend to be curved so that they are able to reflect the wave energy back out to sea.


Fun, random fact 3.Seawalls can be expensive to build, today costing between $4000 to $7000 per metre (£2000 - £5000 per metre)

Fun, random fact 4. There's going to be a sea wall at Singapore's Resorts World! (picture below)


Also, there are different types of seawalls available! :) here are some examples:

Curved/Stepped seawalls & Standing seawalls


Curved or stepped seawalls are designed to enable waves to break and to dissipate wave energy and repel waves back to the sea. The curve can also prevent the wave overtopping the wall, and provide additional protection for the toe of the wall.

Vertical seawalls are built in particularly exposed situations. These reflect wave energy and under storm conditions standing waves will develop. In some cases piles are placed in front of the wall to lessen wave energy slightly

Rubble Mound


A series of rubble mound-type structures such as riprap and revetment are used in less demanding settings. The least exposed sites involve the lowest-cost bulkheads, or revetments of sand bags or geotextiles. These serve to armour the shore and minimize erosion. They may be either watertight, covering the slope completely, or porous, to allow water to filter through after the wave energy has been dissipated.


Groynes (Hard Engineering)


Groyne is a low wall built at right angles to prevent materials from being transported away by the longshore drift as it interrupts water flow and limits the movement of sediments. All of a groyne may be under water, in which case it is a submerged groyne. The areas between groups of groynes are groyne fields. Groynes are generally made of wood, concrete, or rock piles, and placed in groups. They are often used in tandem with seawalls.

Gabions (Hard Engineering)
Gabions are wire cages that contains small rocks to form a wall to protect the coast against erosion and also to protect other coastal structures such as seawalls. For erosion control, caged riprap is used. For dams or foundation construstion, cylindrical metal structures are used.

Plus, gabions are cheaper alternatives compared to coastal protection measures!


Fun, random fact 5. Gabions are also used in civil engineering, road building and military applications! :)
-In a military context, earth or sand-filled gabions are used to protect artillery crews from enemy fire.

Reinforced earth with gabions, Sveti Rok, Croatia.

Okay! That's all under hard engineering for it's advantages! :D Next post will be for it's disadvantages/limitations! :D

Nous aimons la Géographie;
Diyanah

Simple sweet smiles.


That's them looking really adorable ! :D


OREO !



And them otw to East Coast park !


We're at the top of some tower at Siloso Beach.


Us camwhoring in Sentosa toilet.


With the help of a kind stranger :D


Nous aimons la Géographie; Rosma

Breakwaters!

Okay so since Hazwani has posted about our trip to the three sites which are;
1. East Coast Park
2.Pahlawan Beach
3.Siloso Beach

and took pictures of our visit there plus pictures of breaks waters and other stuffs/measures to prevent coastal erosion, i will post about how each of these measures prevent coastal erosion :)

The most common coastal protection that we found at all the three beaches was the breakwaters. Thus, i will be talking more about this.

Basically, breakwaters (also known as bulkheads) are usually made out of granite and are built parallel to the coast of the beach or built with one end linked to the coast. Breakwaters may be small structures and are designed to protect gently sloping beaches and may either be floating or fixed, depending on the depth of the water and the tidal range.

In Singapore, the breakwaters are mostly built with one end linked to the coast and are fixed. Fun, random fact 1. There are 24 breakwaters at East Coast Park.
Fun, random fact 2. Cost of each breakwater is estimated to be around S$1 million.

Breakwaters prevent coastal erosion by creating a zone of shallow water between itself and the coast, so that the waves will break against it before reaching the coast. This way, there would be an area of slack water behind the breakwaters, thus, reducing the impact of the waves on the coast.

However, no matter how useful breakwaters are at preventing coastal erosion, the processes of erosion and sedimentation cannot be effectively overcome at the same time as deposition of sediment at one site will be compensated for by erosion elsewhere and this phenomenon occurs whenever breakwater or a series of such structures is built along coasts. Thus, there are still some disadvantages of breakwaters.

Breakwaters are unable to provide complete coastal protection as they still leave areas of the coast unprotected due to it's small structure. This will leave the unprotected area to be prone to erosion and gradually shrink, namely due to longshore drift.

Also, over the long term of interfering with currents and the supply of sediment, deposition will occur in these waters and beaches can be built up or extended in these waters and the nearby unprotected sections of the beaches do not receive fresh supplies of sediments.
Futhermore, breakwaters are subject to damage, and over-topping by big storms can lead to problems of drainage of water that gets behind them. The wall also serves to encourage erosion of beach deposits from the foot of the wall and can increase longshore sediment transport.

Okay that's the main idea of how breakwaters prevent coastal erosion and some disadvantages of having them. Now, let's look at some of the different types of breakwaters that's available. :)
Headland Breakwaters
A series of breakwaters constructed in an "attached" fashion to the shoreline and angled in the direction of predominant wave approach such that the shoreline behind the features evolves into a natural "crenulate" or log spiral embayment.


Detached Breakwaters


As the name implies, these are breakwaters that are constructed away from the shoreline, usually a slight distance offshore. They are detached" from the shoreline, and are designed to promote beach deposition on their leeside.

Single Breakwater

Single breakwaters may be attached or detached depending on what they are being designed to protect. A single detached breakwater may protect a small section of shoreline. A single attached breakwater, may be a long structure designed to shelter marinas or harbors from wave action.


Okay! So that's all i'll post about for breakwaters! Will post about the other measures that other countries take to prevent coastal erosion in the next post! so stay tuned! :D



Nous aimons la Géographie; Diyanah

Wednesday, June 23, 2010

Loud and cloudy.

Yesterday was the execution day. Inititally, we were meant to go to East Coast Park, Labrador Park and West Coast Park. And thanks to a witty eeny mouse named Rosma, we changed plans and swapped Labrador Park and West Coast Park to Sentosa. That means we have to visit two beaches at Sentosa and they are Siloso Beach and Palawan Beach.


  • East Coast Park
  • Sentosa
It started out weirdly silent especially with Shannon plugging in almost all of the entire morning, being really anti-social. We met up at Jurong East Interchange at 9am. Diyanah was really late. And because of her we missed five trains heading to Bedok of which 1 was not for boarding and another was really packed. Well anyway, Shannon was still keeping to himself when we were at Bedok Interchange. So we decided to text him, that means all of us me, Diyanah, Rosma and Shafiq all at the same time in act of teasing him. HAHA.

1st text: Hi Shannon ! :D
*Shannon looked stunned and turned and smiled to us and said 'what?'*
2nd text: Why so anti-social ?! Tsk.
*He took out one side and said 'I'm not anti-social.*
3rd text: If you don't talk to us we'll push you into the sea later. Hahaha !
*It worked this time and he kept his iPod but still silent though*

During the bus ride in 197, it wasn't at all quiet. A little toddler was entertaining us, disturbing Ros and trying to communicate with us. Well apparently, she was really attracted to Shannon and attempted to bat her eyelashes several times but failed and it turned out that she was squinting her eyes at him ! HAHA! How cute. We laughed till our jaws hurt for what was counted as 11 bus stops. Anyway, the toddler's granny was really nice to us she showed us the way to the underpass that would lead us to East Coast Park. And we finally made it, we stayed there for about 10 minutes, took pictures and head back to Bedok Interchange. Mrs A, it truly is a pathetic project !

Got back to Bedok MRT and headed to Harbourfront MRT, to stop by for lunch at Vivo. How unlucky were we, it was lunchtime ! Perfect. Headed to LJS and it was packed, no more seats. Headed to BK next, and same goes for that. At least, our 3rd stop at McDonalds was fruitful we had a nice table that seats all five of us with a tolerable queue. Ate till 1 30 and decided to go to Sentosa instead. Walked a long way, SLOWLY to the Sentosa monorail. Shannon and Shafiq were complaining that Vivo was so cold. Speaks so much, they're implying that the girls are fat ! TSK. At the ticket counter, Rosma got teased by the malay ticket officer. Funny !

Rosma: Ummm, are we considered as adults or children ?
Malay Guy: How old are you guys ?
Us: 15.
Malay Guy: Are you sure you're 15, you could still pass as children. *chuckles*
Rosma: Hahaha yessss. *paiseh face*

Hahaha how funny, if only we didn't open our big mouths and be so honest with our age, we could get away with paying one dollar less each ! Still, it was hilarious that he thought Rosma was not 15. Grow taller !

We missed the 2 monorails because it was super packed. And the third bought us seats. Speaking of which, we could all fit into the 4-seat bench ! Hahaha squeeeeeezee ! Thanks to the boys with tiny derrieres.

Arrived at Beach Station via monorail. Headed to Siloso Beach first. Shannon spotted a group of boys and a girl from our school. We took pictures and videos. Oh how could i forget, Shannon looked like an absolute retard walking on sand. He didn't want to dirty he's clean Oxford Shoes. So, he walked like he just got circumcised. Hahahaahahaaha. Hilarious.

And our final destination was Palawan Beach. A really long walk from Siloso Beach. The weather was cloudy and humid, helps much. We walked the freaky bridge to this tower nonsense where we climbed many flights of stairs to reach to the top. Halfway up, we paused at the stairs because Shannon was asked to help take a picture of this group of girls in bikinis. Hahaha out of all people him. So we just stoood there rooted like idiots waiting for Shannon. So we reached the top, and the wind was amazing. We indulged in the cool breeze while camwhored as much as possible.

Took the tram back to the monorail station. We went to the toilet to clean up and spent around 15 minutes. We went out of the ladies' to find Shannon and Shafiq standing outside waiting for us with bored faces. Hahaha pity them. Lesson learnt. Never wait for girls to go to the washroom. They take ages ! 

Headed back to Vivo for stroll. Ate ice cream. And Shannon doesn't like ice cream, how strange. He's weird. And he hates taking pictures. Hahaha ! Well too bad, because of that, we have so many pictures of him. 

So thanks for staying till the end, here are the pictures ! Well from my camera and Shannon's. I haven't gotten those from Rosma's camera.

Breakwaters at East Coast Park.




Breakwaters at East Coast Park.






We're at the East Coast Park underpass. And that's Shannon trying hard to be a passerby but apparently, barely anyone was here.




Diyanah giggling at Siloso Beach ! If you don't know this is at Sentosa then you can bury yourself in the sand and don't ever come out.


Shy Shannon is not being anti-social anymore ! And check out the breakwaters in the background.


And yes, we're still at Siloso Beach. Alert: See Mrs. A, we're still doing our Geography project despite the unsightly weather. It was cloudy, with random drizzles and humid. ):




We're still at Siloso Beach.


Look at the picture, it's so hazy. Plus it was drizzling ! And this is at East Coast.

 More breakwaters at East Coast

 And more !

 And a breakwater island at Siloso Beach.

And it's us at Siloso Beach fumbling for a camera to snap a photo of Shannon. HAHA!

Breakwater rocks at Palawan Beach ?

Ooooh a caterpillar spotted during our nature walk from Siloso Beach to Palawan Beach.

The view of Palawan Beach from atop the towers or whatever you call it.






Breakwater island from afar.



Shy Shannon makes an appearance again at Siloso Beach ! Paparazzi !!!! :O

#1 fan: Mr Shannon may i snap a photo of you for memories? I'd like the side with the ear plug on. Haha !
Shannon: Oh no no nooo, i'm not Shannon. I'm Shannon the Shy. 
#1 fan: It's okay, just say 'CHEESE' !
Shannon: Oh damn!




Look ! It's Shannon the Shy ! He's taking a picture of us, how awesome !




Ogling bikini girls ! :O


OMG It's Shannon the Shy again !

 Breakwater island, heading to Palawan Beach.


Diyanah: Shannon the Shy Sir, it's an earthquake ! Hide Sir hide !
Shannon: *covers his head* Save me Diyanah !
Diyanah: Oh here comes the paparazzi Sir !
Shafiq: Peek a boo ! You call me ?




Shannon: OMG MOMMY ! HELPP the earthquake's gettinggg me !!
Shafiq: Shannon the Shy : Picture Perfect :D



Rosma: Diyanah, what's Shannon the Shy doing ? He doesn't want to take a picture with me ):
Diyanah: Oh who cares ! CHEESE ! Now i'm the famous one :D
Shannon: I told you i'm shy !



Rosma: HUHH ?!
Diyanah: Uh wth !
Shannon: Oh no, the paparazzi is here to stay ! They're so lame!

Nous aimons la Géographie; Hazwani