geography urban 2 (climate / fogs)

geography paper 1

microclimate

a climate in a small or restricted area, especially when it differs to the surrounding areas.

Urban heat island effect

the increased temperature in urban areas compared to surrounding rural areas.

Albdedo effect

the reflectivity of certain services:

black surfaces such as roads and black buildings have low albedo

white surfaces have high albedo

absolute humidity

the mass of water vapour in a given volume of air, regardless of temp

relative humidity

a percentage / ratio of the actual amount of water vapour that is in the air.

different between relative and total humidity

relative - the percentage of water vapur

total - the quantity in the water

venturi effect

two buildings with a gap between them causing a sharp air wind speed

the formation of thunderstorms

• ground surface heats and air rises

• the air becomes unstable and causes of a ‘chimney’ of condensed air

• causes ice crystals and they fall as precipitation

• this causes electric charges of the positive crystals

  • causing thunder and lighting

downdraught effect

tall buildings cause the wind to mostly go down (some go up) and this air picks up speed and causes higher wind speeds.

fog

when visibility is less than 1000mand occurs by water droplets and solid particlses

radiation fog

1. caused when there is cooling of land by thermal radiation cooling the close to the surface

2. the cooling reduces the ability to hold moisture and causes the dew point to be reached easier, causing fog

advection fog

caused by warm moist air blowing over a colder area, causing air to reach lower dew point.

Smog

a mixture of smoke and fog which occurs when smoke particulates and sulphur dioxide mix with fog.

photo chemical smog

occurs in drier areas and forms due to fossil fuels, and borning trees and organic waste

particle pollution

pollution which consists of particles suspended. these particles come from natural and human processes

smoke controlled areas: def adv dis

an areas where it is offence to emit smoke from a chimney, normally resulting in a fine.

adv: stops the emissions of gas within urban areas, better air quality, reduces risk of chimney fires

dis: the max offence charge is £1,000 meaning large businesses are mostly unaffected

clean air act: def adv dis:

the clean air act was brought in 1956 and dealt with smog issues, making smog contol areas where smoke is not allowed in domestic properties

adv: improving public health and environmental impact is reduced

dis: may lead to exportation from abroad, worsening the carbon footprint of products and reducing the UK’s economy

vehicle control: def adv dis:

introducing schemes to reduce cars in busy areas, whether that be from the design of cities reducing roads, to low emission zones being introduced

adv: encourages people to have cleaner habits in the way they commute

dis: leads to traffic on the outskirts of the city, with city expansion being an issue

vechile emissions: def adv dis:

car manufacturers have been made to make efficient fuel-burning engines

adv: reduces the impact of vechiles on the road and lowers fuel usage and price

dis: these new standards only apply to new cars, which not many people have

public transport: def adv dis:

introducing more public transport schemes such as bus and train stations and bike paths

adv: reduces traffic, reduces people’s carbon footprint getting to work

dis: can lead to overcrowding of services, can often be unreliable

industry zoning

forcing businesses to emit their pollutants above the immersion layer

adv: decreases fog and smoke, decreasing health issues and keeps businesses still in the city

dis: can have a negative look on a city and the emissions are still being released

the urban water cycle - neame the levels:

source - reservoirs, lakes

water treatment - raw water must be treated with methods such as filtering and disinfection

water distribution - clean water is put into pipes and pumps, where it is transported

use - can be used in many ways such as cleaning, drinking and bathing

wastewater collection - taken back for treatment

wastewater treatment - the physical, chemical and biological treatment processes and discharged into sources

Natural levees: def adv dis:

embankments (turns in the river) are made of concrete and riverbed materials

adv: relatively low costs to maintain and have a nice natural look

dis: can easily be over topped by flash floods

diversion spillways: def adv dis:

emergency areas which are opened when there is flooding

adv: reduce the pressures on the main channel

dis: expensive and can disrupt ecosystems r

river channelisation: def adv dis:

straightening channels with concerete to reduce friction

adv: improved navigation and more efficient flooding

dis: expensive and destroys habitats. can lead to flooding at the bottom of rivers

afforestation: def adv dis:

planting trees to increase interception and reduce water runoff

adv: more natural approach and little construction needed

dis: community not happy, takes long time for them to grow

riverbank conservation: def adv dis:

planting bushes and trees to reduce erosion and roots which stabilise riverbanks

adv: low maintenance and disruption needed

dis: takes a long time and does not reduce major flood impact

floodplain zoning: def adv dis:

restricts land use to a floodplain, allowing it to get flooded

adv: avoids people from being flooded, reducing risk

dis: can be difficult to implement and requires assessment of land

river straightening: def adv dis:

cutting through meanders to create a straight channel

adv: improved navigation, easier maintenance, more space for urban land

dis: can increase floods downstream and can destroy habitats

river restoration definition

removing all hard engineering and adaptations to restore meanders, wetlands and floodplains. this leads to flood management being returned to nature

river conservation

planting vegetation to reduce lateral erosion and riverbank collapse. this can also include introducing native species and awareness to the public

River restoration study - Darlington

• the river was straightened in 1850 to accommodate industrialisation

• in the 70’s the lake was highly polluted with gas and sewer pipes

• in 1995 a plan was made to restore the area into an attractive wetland environment thriving with natural life

  • this was done to maintain biodiversity and reduce flood risks

river conservation study - Blue Loop Sheffield

• throughout the 1800’s, the river was used for industrial purposes such as cooling and exporting coal and goods

• this lead to the river becoming derelict, as well as the houses around the canal

• this was until 1992 when the Sheffield development co-operation helped to conserve the river Don and canal

• the aim was to: encourage biodiversity, create a community to help the river, reducing flood risk and making it a recreational area

SUDS definition

represent the ultimate in realistic yet environmentally friendly replication of natural drainage systems

SUDS: Swale

wide shallow drainage channels which collect and transport water

SUDS: permeable road and pavements

use of porous block paving and concrete

SUDS: infiltration trenches

bioretention basins

gravel / sand filtration beneath reed beds

SUDS: rain garden

shallow landscape despressions planted with flowers and shrubs

SUDS: green roof

SUDS: adv dis

adv: slow down water runoff, provide wildlife homes i urban areas, reduced flooding risk, prevents water pollution

dis: lowered profit when developing, increased maintenance, high initial costs

Case study: Lamb Drove, Cambourne

• this development was apart of a large scale project of introducing SUDS across Europe

• this one included introducing methods such as: permeable surfaces for drives, under drained swale, water butts and filter strips

• this lead to less metal in their water as well as maintenance being 10% less

  • however, it did lower profit’s for developers and concerns were made about exposed water

streategy: greener built environment. def adv dis:

initiatives to use energy and water more efficeintly as well as reducing waste in a more greener way

adv: can improve energy consumption in buildings, enhanced appeal of cities

dis: high initial costs, hard to change what is already implemented

strategy: planed expansion def adv dis

encouraging the conservation of historic buildings and green space.

adv: protects open spaces which act as carbon sinks, maintain hsitorical and tourism heritage.

dis: can be costly to maintain older buildings, restrictions on land use take a lot of time to gain

strategy: carbon neutral developments. def adv dis

building structures such as houses that produce as much energy as they need

adv: reduces impact on environment from all settlements, enhanced reputation

dis: can be challenging to maintain due to cost

strategy: economic opportunities. Adv dis

providing a range of economic opportunities outside of the fossil fuel department e.g. Quaternary sector

adv: can lead to a more sustainabel growth in demand and reduce reliance of fossil fuels

dis: can create economic inequalities due to loss of jobs needed

ecological footprint definition

the impact of a person or community on the environment, expressed as the amount of land required to sustain their use fo natural resources

biocapacity definition

refers to the capacity of a given biologically productive area to generate an on-going supply of renewable resources and to absorb its spill ober wastes

ecological defecit and surplus definition

the difference between the bio capacity and ecological footprint tor a region or country

defecit: when the footrpints exceeds the capacity in the area

surplus: when the capacity exceeds the footrprints in the area