Sec 2 geography unit 5 lesson 4 full version
Transcript of Sec 2 geography unit 5 lesson 4 full version
Chong Boon Secondary SchoolHumanities Department
Geography UnitSec 2 Geography
Unit 5 Lesson 4
“How should cities prepare for floods?
The Cost Benefit Analysis
• For every choice, there are 2 key factors involved.
• The costs (tangible cost and opportunity cost)
• The benefit (tangible and intangible)
Mitigation measures in Singapore
• Regulation– Zoning
– Elevated properties
• Investment in infrastructure– Levees and floodwalls
– Channel improvement
• Disaster preparedness– Forecasting and warning system
– Evacuation drills
Regulation
Refers to rule of law which is enforced by an authority.
States how something should be done.
Zoning & Development control requirements
Zoning
Plans for the physical development of the land and its uses.
Specifies residential, industrial, commercial, recreational areas.
Flood-prone areas are zoned as low-value developments.
Low investments involved, less loss in floods.
Elevated Properties
Raising the properties to a certain height.
Imposing of the minimum platform level (MPL)
Requires buildings to be built above the potential flood level.
Commonly, steps / slopes are built to ensure buildings meet the MPL.
Investment in Infrastructure
Investing in infrastructures like levees, floodwalls and channels
reduce flood impact.Current infrastructure needs to
be maintained to ensure serviceability.
Levees and floodwalls
Levees and floodwalls
Barriers against floods and floodwater.Levees – raised river banks (natural / manmade) used to keep river floods
from the banks.
Floodwalls – man-made concrete structures. Also to keep flood water
away.
Channel Improvement
Channel Improvement
Changes made to the river channel or canal
Increasing capacity to hold water / discharge water
quicklyPrevents overflowing.
Disaster Preparedness
Disaster Preparedness
Cities take pre-emptive steps to reduce damage.
Advance flood warning also helps reduce flood impact.
Emergency drills and training also helps mitigate impact.
Forecasting and Monitoring
Forecasting and warning system
Systems that provide forecasting of weather conditions that would lead to
flooding.Monitoring systems that warn when the drainage systems are approaching flood
levels.Provides reaction time for residents in
affected areas.Opportunity for the residents to take action
(move / evacuate / put up flood barriers)
Evacuation Drills
Evacuation Drills
Critical for cities with large populations.
Plan to evacuate the large number of people in the shortest time.
Drills reduce panic and improve efficiency.
Ensures spread of essential skills and services (first aid stations)
Summary
What are the ways in which regulation, infrastructure and
disaster preparedness can be used to prepare
cities for floods?
Team Task
• In your groups, apply Cost Benefit Analysis to the measures that you have been allocated.
• You have 15 minutes
• Pick the best and write a short speech (1 minute) to explain how it is the most ideal measure. Your team must have a presenter for this.
What are the benefits and challenges of minimum platform level as a flood
mitigation measure?
Benefits Challenges
What are the benefits and challenges of levees & floodwalls as a flood
mitigation measure?
Benefits Challenges
What are the benefits and challenges of channel improvement as a flood
mitigation measure?
Benefits Challenges
What are the benefits and challenges of forecasting and warning system as a
flood mitigation measure?
Benefits Challenges