physcial geography (paper 1) case studys

Where is the river kennet?

Swindon, hungerford, along the M4, in these south

Geology of river Kennet?

Chalk, influences the natural cycle process as chalk is highly permeable (most of the river flows as ground water)

How is water extracted from the river kennet?

Filtered through the chalk (has good clarity, high oxygen and fast flowing), means water doesn’t need much cleaning before before it can be drank

Negative effect of water extraction on the river kennet?

On the stores and flows, as rates of extraction exceed rates of recharge

• 1990 flows = 40%, 2003 flows = 20%

• Falling water table reduced flows but 10-14%

Positive effect of water extraction on the river kennet?

Flooding and overland flow has reduced as the springs have dried out

What is London located on?

Synclinal structure and a artesian aquifer basin, the ground water is trapped by imperishable London clay and gaut clay

• Water enters through the north downs and chilterns , then flows to the centre of the basin

Does the presence of London have a effect on the natural flows and stores

Yes, they have drilled many boreholes which have been overused

• Burning the 19th century stores fell by 90m

• Over the past 50 years a decline in industry has allowed the water table to stabilise

• Since 1990 water table has risen by 3m/ year

What is DACS and who does it?

Direct air capture and storage

Done by climeworks

How does DACS work?

• Air drawn into a collector, CO3 is collected on a surface of selective material

• When full, heated to 100c then pumped underground with water and calcium carbonate and mineralises so can be stored there permanently for years

Why do we need DACS?

IPCC = urgent climate action is needed to half emmisons by 2030

• Need to remove the ‘legacy CO2’

What are the benefits of DACS?

• Location independent = CO2 is everywhere all that is needed is energy and a place for the CO2 to be stored

• Highly measurable = can precisely measure the CO2 levels the plant collects

• Efficient land storage = 0.42 acres can remove 4000 tones of CO2/year (1000x more than trees)

• Carbon negative as no factory’s used to get the CO2 (but needs a lot of energy)

Why is Iceland perfect for DACS?

Has volcanic rock (has air pockets) = when carbon is pumped it can fill the gaps and solidify into the rocks

What is CCS

Carbon capture and storage

Basic bits for CCS

Removal of carbon, from emmisons by thermal power stations and stored in disused oil and gas wells (underground), small scale and carbon neutral at best as the CO2 is still produced

Drawbacks of CCS

• Big costs - drax and Peterhead projects will cost £1 billion +

• Use large amounts of energy - about 20% of a power plants average output to separate and compress CO2

• Needs storage reservoirs (with specific geology- poreus rocks overlain by impermeable strata)

Where is the Colorado basin?

Southwest USA, covers 630 km², through Arizona, Utah, Nevada etc

Source in the Rocky Mountains, only major river in south-west USA

How do humans activities affect the water cycle in the Colorado basin?

Most dammed river in the US ( led to desertification in the lower basin )

Colorado allocated 4.79 billion m³ water/ year

California allocated 5.43 billion m³ water/year

90% of water extracted is used for irrigation

Natural factor leading to positive feedback loops in the Colorado basin?

South-west US experiencing long droughts due to climate change

• Reduction in snowmelt in Rocky Mountain = unreliable source for the river

Water levels in lake mead and Powell have fallen to record levels

Temperatures highest in June-September, July = 27.6 c, January = -1.1 c

Impact on the water cycle in the future for Colorado basin?

Most water comes from snowmelt on rock mountains, the snowpack has reduced due to warmer springs therefore less water into the basin

• This will continue to happen if climate change furthers

Key information- Amazon rainforest?

South America

Goes through Brazil (70%), Peru and Venezuela

6 million km²

High annual temperatures between 25 c- - 30 c (small seasonal change), high annual rainfall (no dry season) - conventional rain all year 2000mm/ year

Conventional rainfall in the Amazon rainforest

1. Heat evaporates Atlantic, westerly winds mean clouds for in in the Amazon basin

2. Rainfall evaporates immediately due to insulation (clouds from West due to winds)

3. Process repeats 5-6x, why 50% of rain is recycled in evapotranspiration

4. Once clouds reach Andes (6000m) rainfall flows down mountain and basin then back to the ocean

Absolute humidity?

Mass of water vapour in a given volume of air

Relative humidity?

Mass of water in a given volume as a ration of the mass needed to saturate it

Water cycle flows and stores in amazon rainforest?

• High temperatures are a response to insulation

• Clouds ensure that there is no extreme temperatures (no seasonal difference)

• Water loss is from river flows and atmosphere vapour moving - made equal from, flow to the Atlantic Ocean

Carbon cycle flows and stores in the amazon rainforest?

• Amazons climate creates ideal conditions for plant growth, NPP 2500g/m²/year and biomass is 400-700 tonnes/ha

• Large trees contain 180 tonnes/ha carbon above ground, 40 tonnes/ha carbon in the roots

• Amazon is an global reservoir of stored carbon (2.4 billion tonnes/year) due to soil stores averaging 90-280 tonnes/ha

• Carbon exchanges are rapid

• High temperatures = decomposition is definite and the quick release of CO2

• Carbon fluctuations are high due to photosynthesis

• Acidic soils = reduced carbon and nutrient stores

Physical factors on the water cycle in the amazon rainforest - temperature

High temperatures = high evapotranspiration, high atmospheric humidity, thunderstorm clouds and intense precipitation, water cycled from land and trees and atmosphere

Physical factors on the water cycle in the amazon rainforest - rock permeability

• Impermeable catchments have mineral water capacity = rapid water run off

• Permeable and porus rocks (limestone) store water = slow run off Permeable and

Physical factors on the water cycle in the amazon rainforest - relief (slopes)

Basin has many lowlands , areas of gentle relief water moves across or into the soil to rivers. Andees create high relief so water can run off onto area of gentle relief or rivers/lakes

Physical factors on the carbon cycle in the amazon rainforest - temperature and rainfall

• High temperatures = rainfall and sunlight therefore simulating NPP (responsible for 15-25% of NPP)

• High temperatures = rapid decomposition by bacteria and fungi, release nutrients into the soil (taken by tree immediately and emit CO2 returned to atmosphere)

Physical factors on the carbon cycle in the amazon rainforest - geology

• Mainly igneous and metamorphic, carbonates are absent

• In the west basin outcrops of limestone form (significant in the slow carbon cycle)

Human activity on the carbon cycle in the rainforest

• Deforestation exhausts the carbon biomass and reduces input of organic matter to soils and exposes to high sunlight

• Deforestation destroys a key nutrient store, cause soil to lack nutrients as its washed away rather than taken by the trees

• Soil is unprotected b trees and is eroded by surface runoff

Management strategy in the amazon rainforest - protection (legislation)

• 1988 brazillian government established conservation areas, cover an area 20x the side of Belgium,

• 2015 44% of the rainforest was national parks etc

Management strategy in the amazon rainforest - rainforest projects

Parica project (in rondônia), aims to develop 1000km², planned for29 million tropical hardwood trees planted over 20 years (no biodiversity, monoculture)

Management strategy in the amazon rainforest - improving agricultural techniques

• Diversifying crops - soil fertility by rotating crops and combining livestock, integrating crops and livestock allows 5-fold increase in ranching productivity and slows deforestation

• Human engineered soils - made from charcoal, waste and manure, charcoal atracts micro-organisms and fungi (long term fertility), still being researched could allow intensive and permanent cultivation (reduce deforestation)

Deforestation in the Madeira drainage basin

In Amazonia deforestation averaged 17,500 km²/year from 1970-2013, since 1970’s 1/5 of primary forests has been destroyed or degraded

Events at the Madeira drainage basin

• April 2014 floods occurred on the madiria river (largest tributary of the amazon)

• At Porto Velho the river was 19.68 m higher than normal

• 60 died, 68,000 families were evacuated and outbrakes of cholera and leptospirosis

Why was deforestation present at the Madeira drainage basin

Cleared for subsistence farming and cattle ranching, mostly occurred on the steep slopes of the Andees

Was heavy rain the reason for the events at the Madeira drainage basin?

No, mainly due to deforestation in Bolivian and Peru

• From 2000-2012 30,000 km² of rainforest was destroyed

• Ment there was much less storage for water and accelerated water runoff

Where is the arctic tundra?

8 million km² in northern Canada, Alaska ad Siberia

Southern limit is the 10 c July isotherm (climate limit of tree line)

Ground conditions of arctic tundra

Permanently frozen, only the top layer thaws in the summer months

Flora and fauna in the arctic tundra

Few dawarf species, treeless, some areas are bare due to such harsh conditions

Annual temperatures and rainfall in arctic tundra?

• Mean temperatures below -15 c, for 8/9 months tundra has a negative heat balance, height oof 10 c in the year

• Less than 100mm/year (most falls as snow), height in august - 35mm

Other info on the arctic tundra

• Permafrost stores around 1600 GT of carbon

• Thawing permafrost causes land to collapse

• High temperatures will impact tundra as greater surface water and CO2 emmisons (could cause global consequences)

Characteristics of the water cycle in the arctic tundra

• Low precipitation most falls as snow, small stores of water moisture owing to low absolute humidity

• Limited evaporation as suns energy used melting snow, so ground stays frozen

• Limited transpiration as sparseness of vegetation (growing season is 3 months long)

• Limited groundwater and soil moisture stores as permafrost prevents infaltration, perculation recharge

• Melting permafrost and snow increase rive flow spring, Yukon river discharges 24,000 cumes in summer

• Wetlands stop drainage, Alaska has 3 million + lakes

Characteristics of the carbon cycle in the arctic tundra

• Permafrost is a carbon sink (1600 GT) - due to low temperatures = slow decomposition

• Carbon in Alaskan soils is 5x greater than the biomass

• NPP is less than 200 g/m³/year (biomasss is 4-29 tonnes therefore small)

• Due to climate change permafrost is becoming a carbon source

Seasonal change in the arctic tundra

Summer = high surface water (due to melting of permafrost and evapotranspiration from standing water)

Summer , there’s a 3 month growing period where small plants grow

Physical factors on the water cycle in the arctic tundra - tempurature

• Freezing for most of the year (water is stored in the permafrost), summer active layer thaws and water flows on the surface

• Humidity is low al year and precipitation is sparse

Physical factors on the carbon cycle in the arctic tundra - temperature

Low temperatures = not many plants so carbon store in biomass is small, low levels of photosynthesis and NPP, reduce flows of CO2

• Management strategy in the arctic tundra - insulated ice and gravel pads

• Separates structures from the permafrost, used for airports roads etc

• Spine road at prudhoe bay lies on a 2m deep pad

Management strategy in the arctic tundra - elevated piles

• Steel pilings (1/2 diameter) to support the building and raise of the ground

• Reach about 14m into the ground

• Prevents heat transfer into the permafrost

• Allows cold air to circulate around the houses

Management strategy in the arctic tundra - drilling laterally beyond drilling platforms

• Allows drills to move laterally / horizontally under the surface

• Allows oil operations to protect environmentally sensitive lands and get the needed resources

• Allows drills to reach and avoid sensitive surface and subsurface environmental features

Management strategy in the arctic tundra - supercomputers to model oil and gas reservoirs (AI)

• Creating seismic waves in the ground, the supercomputer is able to record the waves and create a 3D model of the interior crust

• Identify areas of gas and oil without having to drill to prospect (environmentally damaging)

• Allows companies to see the economic viability of a new reservoirs before drilling

Management strategy in the arctic tundra - refrigerated supports

• Over ½ of trans-Atlantic pipeline runs above ground so hot oil doesn’t melt the permafrost

• Pipeline is elevated on 78,000 refrigerated supports

• Every support is equipped with 2 tubes that descend, absorb heat, releases it into the air, then circulates back into the ground

Basic information on he Alaskan oil and gas industry

• North slope in Alaska, oil and gas found in 1968, mainly done in prudhoe bay

• A harsh climate (cold) and long periods of dark in winter

• Permafrost, very remote and limited access

• Accounted for ¼ of USA’s oil production (1990’s)

Impact on the water cycle for the Alaskan oil and gas industry

• Melting of the permafrost increases runoff therefor flooding increases in the summer (15m of permafrost thawed in 60 years)

• Strip mining of sand and gravel crate artificial lakes (disrupt drainage)

• Water is abstracted from creeks and river for industrial use, BP uses water from the big lake and Kaparuk river

Impact on the carbon cycle in the Alaskan oil and gas industry

• Construction and operation of oil heating the ground, dust deposition which increases the Albedo effect (melts permafrost)

• Removal of vegetation cover ( reduces photosynthesis = increase in CO2) which insulates the ground

• Loss of permafrost = increase of CO2 (7-40 tonnes/year)

• CO2 emissions have increased by 73% since 1975 on the north slope (due to permafrost thaw)

• Slow growing tundra = regeneration could take decades

Water cycle management - forestry

• Many programmes funded to protect the rainforest (water recycled 6x)

• Brazil has received multilateral support

• 75% reduction in deforestation 2000-2012 (stabilised the water cycle)

• Offsetting 1.4 million tonnes of carbon/year, promoting ecotourism

Water cycle management - water allocations

• Agriculture is the biggest consumer of water globally

• Accounts for 70% of withdrawals and 90% of consumption

Water cycle management - drainage basin planning

• Most effective management of water resources

• Able to target specific areas

Small scale carbon cycle management - afforestation

How does it work

• Planting trees in deforested areas or unforeseen areas

• Trees are carbon sinks and reduce flood risks

Examples

• Chinese government (1978) aimed to afforestation 400,000 km² by 2050, 2000-2009 30,000km were planted (poplar and birch)

• UN scheme places a monetary value to protect rainforests

Small scale carbon cycle management - agricultural practices

How does it work

• Produces 100 million tonnes/year of methane

• Controls the way manure decomposes (manure management)

• Improve quality of food, less converts to methane (livestock management)

• Poly culture growing plants with trees to stop erosion

Examples

• Mix methane inhibitors with livestock feed (livestock management)

• Store manure in anaerobic containers (manure managment)

• Avoid heavy use of machines on wet soils (erosion)

Small scale carbon cycle management - wetland restoration

How does it work

• Water table near the surface = ground above permanently saturated

• Population growth, economic development places pressure on the wetlands

• Raises local water table by removing flood embankments

• Eater levels are kept high by installing sluice gates

Examples

• Occupy 6-9% of earth land and 35% of carbon pool

• In 48 US states wetlands have ½ since 1600

• Canada has lost 70% of wetland, each stored 3 ¼ tonnes C/HA/year, 112,000 are being restored

• Grade 1 farmland in UK is being restored

Large scale carbon cycle management - Kyoto Protocol

• 1997-2012

• Countries agreed to a legally binding, reductions in CO2 emmisons

• EDC’s are the biggest polluters but we’re exempt (china and India)

• AC’s refused to ratify the treaty (USA and Australia)

Large scale carbon cycle management - Paris climate convention

• 2015 (implemented in 2020)

• Aim to reduce CO2 emissions by 60% of 2010 levels by 2050

• Keep global warming under 2 c

• Country’s set own targets, not legally binding

• AC’s send money to EDC’s and LIDC’s to help them achieve there targets

Large scale carbon cycle management - COP 28, Dubai

• 2023

• First time fossil fuels have been mentioned by COP

• Not legally binding document

• Recognised global emissions will peak before 2050, developing countries may peak later

Cap and trade - how it works

Government sets a emissions cap and emission allowances consistent to the cap, company’s can buy larger allowances from company’s that don’t use all there allowance

Problems with cap and trade

• No incentive to follow as carbon prices are low ( £60/tonne)

• Fines are low and not always enforced

• Can produce in a country with high/ no cap (China)

Will cap and trade make a difference

• Only if it is followed globally and strictly

• If the world reduce the cap every couple of years it would force the company’s to lower there emissions

Misfit stream in nant Ffrancon

Afon Ogden

• A stream that clearly didn’t form the landscape its in

Roche moutonnèe in Nant ffrancon

Carved by glacier moving north east down the valley

Rock stop in Nant ffrancon

Rhaedar Ogden

• Formed when the valley was deepened, rock harder so doesn’t erode

• Waterfall is 100m heigh

Corrie in Nant Ffrancon

Cwm Idwal

• 1 ½ km long, 1 km wide, deeper than nearby corries due to it having greater volumes of ice, lies on a geological weakness

Ribbon lake in Nant Ffrancon

Llyn Ogwen

• Due to softer rocks or thinner glacial ice

Hanging valley in nant Ffrancon

Cwm Bval

• Glacier that connected to a larger glacier

Glacial trough in Nant Ffrancon

Nant Ffrancon

• Glacier moving north-west, a misfit stream

Lateral morning in Nant Ffrancon

Deposited rock on the side of the glacier

Tarn in nant Ffrancon

Llyn Idwal

• Not a circular shaped glacier

• 1 ½ km wide, 375m deep

Arète in Nant Ffrancon

Crib Goch

• Knife edged, jagged ridge bettween 2 corries

Pyramidal peak in Nant Ffrancon

Yr Wydafa

• Mount snowden formed by 3-4 corries (has been weathered)

What is isostatic rebound (Laurentide icesheet)

Isostatic lowering from the weight placed on earth crust but does rebound upwards when weight is removed

Lake Agassiz

123,500 miles² long, 400 m deep

Basic bits for Laurentide icesheet

• Covered North America 95,000 - 12,000 years ago

• Maximum extent to 37 degrees north around 14,000 years ago

• Centred around Hudson Bay

• 3km thick

• Ice sheet erosion Leeds to a less varied effect than alpine glaciers

• Margins of ice sheets, several lobes formed (gave some distinct features to the landscape)

What did it leave behind (Lake Agassiz)

• Ridges of sand stretching across parts of Minnesota where beaches were

• Flat, rich soils of the river valley lakebed

• Peatland of big bog state park and red lakes, now among minnesota’s largest bodies of water

Tectonics role on the Laurentide ice sheet

Moves rock (eroding them) to create steeper and more dramatic valleys (Misquan hills) In the flat landscape

Temperatures role on the Laurentide ice sheet

Needed to be cold for years (thousands) and around 8-10 c bellow current temperature

Lithology and structure ( geology ) role on the Laurentide ice sheet

• Shale which is layers of weaker rock placed together due to tectonics

• They are slanted which erodes them (upper and lower red lakes)

Latitudes role on the Laurentide ice sheet

37 degrees north from the equator is the furthest extent of the ice sheet

• Needed to be more polar, cold enough for ice to form

Scale role on the Laurentide ice sheet

• Covered an entire continent ( 13 million km²)

• Quaternary period lasted 2.6 million years ago, this lasted from 100,000 years ago to 10,000 years ago (only 90,000 years old)

Upper and lower red lake (erosional) - Laurentide ice sheet

• Example of rocks tilted by tectonic fources so the dip of the layer is almost vertical

• Allows water to get between the layers (weathering) to break up the rocks (slate)

• Laurentide ice sheet gouged striesations (10,000 yeas ago), seen at Manitou rapids on Rarny rivers

Alexandria moraine ( Wadena lobe) - Laurentide ice sheet

• From north-east Canada

• Red due to sandstone and shales

• First deposited the Alexandria moraine, formed drumlin fields and finally formed the Itsaca moraine

Alt amount moraine (des moines lobe) - Laurentide ice sheet

• Coloured tan-buff

• Clay rich and calcareous due to shale and limestone

• Source in north-west

St croix moraine (superior lobe) - Laurentide ice sheet

• Ground moraine with red iron rich sediments from St cloud north-east

• Set of terminal moraine which hoes from St cloud to Minneapolis and St Paul’s

• Caused textured till with basalts, gabbro, granite and red sandstone

The Misquan hills - Laurentide ice sheet

Worn down, highest peaks are now 500-700 m

Location of grand Dixence dam

• Head of the Val des dix

• South-west Switzerland

• Highest gravity dam in the world

Why is the location of the Grand Dixence Dam good

• Was already a good shape (basin)

• Has annual snowfall (fill up the lake)

• Cost 1600 million Swiss francs

• At a natural narrowing of the valley (maximising water storage)

Random facts of the Grand Dixence Dam

• Constructed in 1960’s

• 285m high and 200m wide

• Can store 400 million m³/year

• Produces 2000 GWH/year, powers 400,000 houses

Impact of the Grand Dixence Dam on tourism

• Still attractive to walkers and cyclists

• Pumping stations are underground so the asthetic of the glacial landscape isn’t ruined

• Projections on the side of the dam creates more opportunity’s for tourism

Positive impact as tourism has increased as more methods to reach the dam and the glacier as well as helicopter rides and guided tours

Impact of the grand Dixence dam on the Borgne river

• Reduced flow into the river

Negative as higher concentrations of pollutants at Les Haudēre, from agricultural and domestic sources and is more concentrated

Problem with sedimentation on the grand Dixence dam

15% of water is used to remove sediment, when water is stored behind the dam

Lack of flow = loss in energy

Where does the sediment come from in the grand Dixence dam

The glacier abrading up the river and melting, means its depositing sediment