Storm water Flashcards
purpose of storm water design
regulate storm water runoff so that LOS are protected and adverse effecct are minor, include biodiversity, flood damage, erosion
building act states what min LOS
safeguard people
flood with 2% chance should not enter buildings
should convey storm water to the appropriate out fall with no blockages etc
more flood mitigation requirements from CCC
need o.5 m free board above flood level of x year event for all habital floors
define secondary flow overland
considerations affecting future LOS
sea level rise
climate change
land settlement
future development
discharge consent needed for
both construction and operation
consetn conditions vary between councils
managment plan needed to show compliance
what is aceptable flow path
not in private property because easily blocked
why can flood protection be hard
town in wrong place, los too expensive
instead control retreat
design for floods
how to estimate flood flows
rational method q=CIA
what is free board and what does it do
provides contingebcy against, flood flow predictions, sea level rise. is putting houses on slats etc
why treat storm water
environmental effects
asthetics
public health
recreation, like fishing
contaminant protection statergies
community education
end of pipe treatmentp
planning controls
at source treatment
example of at source treatments
biofiltration
sand filter etc
end of pipe treatment
wet lands dry lands
large sand filter or somthing
why are chch soils good and bad
pervious, good for drainiage, not for treatment.
what info is needed for design
infiltration characteristics
source of contamination (only roof can be discharged quick
