Class 4- climate change and SWM Flashcards
1
Q
How does climate change affect SWM?
A
- changes the intensity and frequency of rainfall events.
- makes it harder to plan for and predict, flow increases 10 to 20% every 50 yrs
- dont have the hydrology guidelines so we can’t properly plan
- damage in existing infrastrucutre
2
Q
List the reasons for concern caused by climate change
A
- threatens ecosystems
- extreme weather events
- disadvantaged people get the worst of it
- impact on biodiversity and economy
- irreversible damages
3
Q
What does the minor systems of the dual drainage system do?
A
- provides conveyance for high freqency, low intensity events.
- hot and dirty goes into minor systems and is treated
4
Q
What does the major system of the dual drainage system do?
A
- conveyance for high intensity, low frequncy events.
- goes straight to the rivers.
5
Q
What is the volume that we design for?
A
100 yr return period volume, the amount of rain that falls in a 24hr period
6
Q
Explain the ostrich approach
A
- no adjustment to infrastructure to accommodate climate change
- uses historic design flows and accept that it’ll wear out over time
- cost spread out over time for maintenance and exchange
7
Q
explain the chicken little approach
A
- design using future design flows.
- build to the max
- expensive to begin with
- might overshoot
8
Q
explain the mulligan approach
A
- design something that is suppose to last only 20 yrs
- redo it 20 yrs later
- cheap at the start, but operating/maintenance cost adds up over time
9
Q
What is the major system approach?
A
- aka treatment train approach, a series of BMPs
- source BMPs (i.e. greenroof)
- conveyance BMPs (try to stop water from entering streams and pipes. i.e. infiltration trenches)
- source and conveyance BMPs take care of fast hot and dirty
- end of pipe BMPs as the last resort (forebay in pipes to get bad stuff to settle down. SWM ponds)
