•Urban 3 Flashcards
What are a range of climate variables?
Pressure (millibars) Humidity (%) Precipitation- type/ amount (mm) Atmospheric conditions- pollution Wind - speed/ direction Temperature- max/ min
How does air quality vary in urban and rural areas?
Poorer in urban areas as pollution from vehicles and industry in particular Diesel engines will release particulates
How does temperature vary in urban and rural areas?
Urban temperatures are higher
Buildings and people give off heat
Big difference in winter due to central heating
CBDs have cafes and kitchens that release heat via vents
Especially at 7-10pm as outside colder
Urban heat island effect
Urban areas are warmer than the surrounding countryside
An average 2-4 degrees higher in urban areas
Lower winds due to building height and urban surface roughness
Urban pollution and photochemical smog can trap outgoing radiant energy
Burning fossil fuels for domestic and commercial use
Precipitation
Higher rainfall in urban areas
Higher temperatures encourage low pressures
UHIE generates convection= ground heated = rapid evapotranspiration = cumulus clouds
High rise buildings created air turbulence
City pollution causes an increase in cloud formation
Fogs and thunderstorms
Particles encourage fog under high pressure
Cities undergoing industrialisation have higher fog levels
Thunderstorms develop on hot and humid air
Wind
Buildings have frictional drag on the air and change speed
Turbulence caused by various building heights
Air quality
Poorer in urban area
Combustion of fossil fuels form vehicles and industry
Varies with time of year
Smoke and fog = smog
What is the water cycle?
Water is uptaken into the water treatment plant before if is cleaned and transported
It’s then distributed to houses, factories etc.
It will then go to the sewers where it will be treated, recycled and placed back into the source
Drainage basin inputs
Precipitation
Drainage basin stores
Interception Surface storage Soil storage Channel storage Groundwater storage Vegetation storage
Drainage basin transfers
Throughflow/ stemflow Surface run-off Infiltration Throughflow Percolation Groundwater/ baseflow
Drainage basin outputs
River run-off
Evaporation
Transpiration
What is peak precipitation?
When rainfall reaches its highest level
What is rising limb?
When throughflow reaches the river and creates a rapid increase in discharge
What is falling limb?
When discharge decreases and it is released slowly
What is discharge?
The amount of water originating as precipitation which reached the channel by surface run-off, throughflow and baseflow
What is Bankfull discharge?
Occurs when a river’s water reaches the top of its channel. Any further increase will result in flooding
What is lag time?
The period between maximum precipitation and peak discharge
What is baseflow/ groundwater flow?
Maintains the river’s flow during periods of low precipitation. Through rocks & soil deep down. Slow down transfer of water
What is flashy?
A short lag time
What is peaky?
A higher peak discharge
Who designs and implements the SUDS?
The Floods and Waters Management Act 2010 (FMWA)
What do SUDS aim to achieve ?
Reduce damage from flooding Improve water quality Project and improve the environment Protect health and safety Ensure stability and durability of drainage
What is SUDS?
Sustainable urban drainage systems
What are the 4 key criteria of SUDS?
Quantity
Quality
Amenity
Biodiversity
Why are SUDS sustainable?
They manage runoff volumes and flow rates
They protect or enhance water quality
They are sympathetic to the environment
Provide a habitat for the wildlife
Encourage natural groundwater recharge
Integrate with public spaces (SUDS)
Create multi-functional use areas and provide amenity
Incorporated into traffic calming and parking areas (on street and car parks)
Manage rainfall at source (SUDS)
Surface run off should be captured as close to where it falls as possible
Mimic natural drainage (SUDS)
Designed to match natural drainage routes, infiltration rates and discharges as far as possible
Design for water scarcity (SUDS)
Incorporating rainwater/ grey water re-use facilities
Enhance biodiversity (SUDS)
Consideration for landscape and biodiversity
Link to wider landscape (SUDS)
Blue and green infrastructure should be considered
Fit with local landscape and topography
Design to be maintainable (SUDS)
Outset maintenance requirements reflected in design
Have regards to historic environment
Should be complementary to the heritage of the area
Show attention to detail (SUDS)
Ensured that they function as intended
Rain garden
Soil storage
Increase lag time
Green roof
Surface storage Reduces surface run-off Slows lag time Slows lag time Transpiration Vegetation storage
Regional wetland
Surface storage
Wildlife (vegetation)
Swale
Artificial channel
Extra channel storage
