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Land Reclamation :smiley: - Coggle Diagram
Land Reclamation :smiley:
Definition
:explode:
Known as
land fill
, a process of creating a
new land
from oceans, seas, riverbeds or lake beds.
Land reclaimed = reclamation ground or land fill
Materials of Land Reclamation
:warning:
Sand
Hill cut
Clay
Boulders, cobbles and gravel
Rock
Reason to Reclaim Land:
:question:
Human activities
eg: poor farming methods
Derelict Land
become
damaged by industrial w/o treatment
. Treatment = demolition & levelling.
Waterlogged land
eg: swamps and wetland
Damaged land due to natural hazards
eg: fires
Land scarcity
Difficult to find new land to restore or improve
eg: rising demand for land (land value vs. population density)
Benefits
:star:
Feasible
solution
to the prob. of overcrowding
Further growth
of a country's industry
Expanding
the carrying capacity of land
Used for for multitude of purposes
Increase
the availability of arable land
Land Reclamation Method :recycle:
Draining of submerged land
to reclaim wetlands/land for
agriculture use
.
Deep Cement Mixing
Used when the
materials displaced by dredging/draining
; might be contaminated. then, needed to be contained.
Infilling Method
Most simple; fill w/ large amt. rocks/ cement > fill w/ clay & dirt until desired height.
Material used = Infill
Land dredging
Advantages :check:
More
lands, buildings and better infrastructure
can be built.
Reclaim lot of lands from flooding
Increase land area
Disadvantages :green_cross:
Can be damaging to corals & marine life
due to
wrong selection
of poor knowledge of the subject
Techniques :pen:
Direct Pumping
Used when seabed is
deep
/underlying seabed soil is
soft
.
6-8m deep = bottom dumping
Fill mat. dumped at designated location; by opening the bottom of the barge
sufficient draft & clearance required.
not suitable for
granular material
,
stiff clay & soft clay
Rehandling pit method
Transporting sand by barging and dumping fill mat. (clay or rock) in the pit for
temporary storage
Location: At depression on a firm seabed or created by dredging (pit stability is analyzed)
Dredging
the sand using one cutter suction hopper dredger then
transport
it to the rehandling pit
another cutter suction dredger fill the reclamation area at the handling.
Hydraulic Filling
Suitable for granular; not for shallow seabed.
Transfer fill to the reclamation site by dredger, barge, pipeline
Place fill mat. as mixture and process H2O in the reclamation area.
By floating equipment like dredger, fill mat. dredger from a borrow or dredging area.
Fill mat. ratio adjusted following the grain size of fill mat.
Dredging
Dry method
Suitable for filling mat. from land source (rock, hill cut & clay fill)
vulnerable to
soil liquefaction
when there is
seismic activity
.
Sand spreading
Spread sand over water with sufficiently high water level above seabed; each grain will fall gradually thru water and rest gently on seabed.
When sand touch seabed,
impact
force on the ultra soft soil is
very small
Hydro-namic drag keeps the particle velocity relatively constant
The
impact
force of the sand grain on the seabed is
negligible
.