urban drainage Flashcards
3 ways to describe urban surfaces
-impermeable
-steep sloping
-low infliltration
what is catchment management
ctahcment management looks at the interactions between water and its surrounding land and tries to reduce issues associated with urban drainage
water movement through urban catchments on the hydrograph
high peak discharge
short lag time
3 types of catchment management
dredging
dams/resevoirs
flood defences/channel management
what is dredging
dredging is the removal of sediments in the channel using machinery to deepen the river alowing smoother flow
negatives of dredging
causes water to move more turbulently enhancing flood risk further downstream
what are dams/resevoirs
dams manipulate water flow and act as a water store and source
negatives of dams/ resevoirs
creation of resevoir is environmentally degrading by eroding large valleys
what are flood defences/ channel management
the physical alteration f the chanel
e.g channel straightening, flood walls, drainage pipes
negatives of flood defences/channel management
worsens flooding downstream e.g drainage pipes rapidly remove water
expensive
reuire maintenance
environmentally damaging
what are SUDS
SUDS are systems designed to control the flow of water through urban settlements sutainably using natural drainage rather than construction and machinery
3 types of SUDs
green roofs
retention pond
wetlands
positives of wetlands
detain flow
remove urban pollutants
increase biodiversity of the area
negatives of wetlands
vulnerable to high sediment inflows
require baseflow
positives of retention ponds
hold stormwater
remover urban pollutants
negatives of retention ponds
no reduction of run off volume
high land take
positives of green roofs
infiltrate and retain precipitation
ecological and aesthetic
work in high density environments
negative of green roofs
costly
inappropriate for steep roofs
require maintenance
aims of the river chess project
reduce flood risk
create aqau-scape by increasing channel capacity
create consistent flow to alleviate flood risk
actions of the river chess project
increase depth of the 100-metre channel using coir rolls
remove trees to improve lighting and reduce risk to properties
attitudes and support of the river chess project
organised by the Buckingham City council
worked alongside local clubs and estates
support from local stakeholders
aims of cheonggycheon river project
reroute traffic
create green space social sustainability
revive the history and culture
reduce density
actions of the cheongycheon river project
concrete cover dug up
widening of the channel
attitudes to cheongycheon
business owners did not agree
result and success of the cheongycheon river project
created habitat for widlife
average daytime temps dropped 4’C
how much did korea river restoration cost
380 million won
how long did it take (cheongycheo)
2 years
how have curitiba protected themself from flood risks
located parks alongside riovers and river basins and protected the land
nearby woodlands slow infiltration opf rain and use it lowering the peak discharge
lakes in parks act as storage points
how much green space does the WHO recommend
16 metres squared
