drought case studies

8/3/2019 Drought Case Studies

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Drought A long period of time when precipitation is consistently

below average for a region

Affects a wider area than different extreme weather events

It also has a longer duration

Droughts have a slow onset, it creeps up gradually

The definition of a drought varies between countries

Effects are more easily prevented

Droughts are affected by the level of development

People die indirectly e.g. famine

HUMAN CAUSES:

- Over-use of water

- Over-grazing

- Excessive farming and cultivation

- Deforestation

- Global Warming?

NATURAL CAUSES:

- Below average precipitation

- High pressure systems

- Blocking highs

- Aeolian (wind erosion that takes away top soils = dust storm)

- El Nino

- Global Warming?



MEDC Murray Darling Basin, Australia, 2007

A.K.A, The Big Dry . The Murray Darling Basin is in SE Australia and holds 75% of Australias water. It makes up

70% of Australias irrigated cropland producing 40% of agricultural produce (55,000 farmers who produce

virtually all stone fruit/ citrus/ veg/ cotton/ rice). Its as big as the size of France and Spain combined, and is

home to 2 million people.

CAUSES

y EL Nino/ La Nina

- Normall y , trade winds blow from eat to west ( from South America towards Indonesia

and Australia), which blows warm air towards Australia. This creates warm and dry

conditions on Peru and tropical, wet climates in Australia; Peru are left with high

pressures and Australia are left with warm air = low pressures, hence the wet climate.

- However with El Nino, every 3 to 7 years, the trade winds stop, also stopping to East to

West pattern. The sea recedes back to Peru rather than over to Australia This flips the

climates around, giving Peru tropical and wet climates whereas Australia gets unusually

high and dry conditions. This creates DROUGHT. (The opposite to this is La Nina, where

Peru gets the drought) - In 2006, just 1317 billion litres of water were in theMBD this was 25% less than the

extreme drought of 1902 and way below the average of 222,000 billion litres available.

EFFECTS

y AGRICLTURAL:

- Irrigation water was cut, leaving crops without water water was given to humans and

livestock first.

- Harvests were decimated

- Annual crops werent planted, creating shortages for future seasons- Incomes shrank considerably, leaving thousands of farmers in debt

- Farmers began to abandon their land completely

- SOCIAL:

- Rural communities became ghost towns as many moved away

- Rural suicide rates almost doubled

- Food imports rose, meaning so did prices

- Energy and water prices rose by 20% from 2008, and more polluting and expensive

energy sources had to be used

- Agricultural workers got subsidies and counselling for free

- Water restrictions were put in place In all major cities ( It has stages 1 to 8, and the

summer of 2007 was at stage 5)- Many were only allowed 4 minute long showers each day

- ENVIRONMENTAL:

- Loss of vegetation and wildlife

- Soil erosion weakened the land

- Declines in water quality

- Toxic algal outbreaks in depleted rivers and dams/lakes

- Bush fires and dust storms increased



- Snowy Hydro Electricity Scheme were forced to rely on gas-fired,polluting power stations

- Reservoirs dropped to an average of 12% capacity.

- ECONOMIC:

- Wiped 1% off Australian economy in 2007,cutting government spending

- 60% of businesses in Victoria were affected by the drought, and 34% of rural businesses

reported a major impact ( compared to 10% in urban areas)- Alpine Shires, who get 80% of their income from tourism, suffered

- Resource base on farms were eroded, and takes 5 years for a replanted tree to grow

fruit again without GM

- 2008 vintage wines were crippled due to the 2007 water shortages, seeing a 40% drop in

production

MANAGEMENT

There are 5 main ways to manage drought inMEDCs.

1) Reducing demand Hosepipe bans, paying for consumption of water (meters), public

campaigns and educating people about how to use water during droughts.

2) Water collection/ distribution Repair leaks in infrastructures, government or business

decision3) Adapting farming techniques reducing irrigation, use Mediterranean crops, use gene

technology

4) Recycling/ Conserving water recycle usable river water, use grey water, reduce peoples

water footprint

5) High tech strategies Desalination plants, urban dams built near parks

Australias management:

- Australian Government Water Fund, a nationwide programme with fundings of $2 billion

from the government, concentrating mainly on water solutions and future generations. The

main focus was infrastructure repairs, and creating sources for water.

Its made of 3 programmes:

y

Raising National Water Standardsy Community Water Grants

y WaterSmart Australia this aims to accelerate developments of smart technologies e.g.

Lake Brewster Water Efficiency Programme 2007; It used its money to create storage

improvements, and secure sustainability for all water users, managers and deliverers. It

saved 10 gigalitres of water and 1100 acres of wetland due to its river flow

management.

- Farming changes, particularly crop and pasture management including:

y Genetically modified plants that are drought resistant, withstanding periods of intense

heat and dryness they yield 5%MORE in these periods.

y Sustainable farming, as land where trees have been felled are more likely to be

vulnerable to drought. Three main aims are to reduce livestock to stop over grazing,

plant native shrubs that can withstand soil erosion and protect other produce, and thisleads to lower soil moisture evaporations. OR reduce ploughing to improve soil

structure.

- Lastly, smart managements were created. Desalination plants inMelbourne,2007, converted

salt water into water to be used for watering plants and parks saving the precious drinking

water. Also, Urban dams and resevoirs were created near parks and pitches to store grey

and rain water, to feed the plants rather than use drinking water.



LEDC Sahel Belt, Africa

The Sahel drought began in

the late 1960s and into theearly 1980s, was the worst

encountered drought of the

20th century.

CAUSES

A massive drought that struck parts of Northern Africa in the 1970s and 80s may have been the

result of a natural climate cycle. Up to now, many scientists thought the drought in the Sahel zone

was caused by humans over-using natural resources in the region.

But a new study in the journal Science shows how a combination of ocean temperature and loss of

natural vegetation could have been the sole reasons for the drought. The drought pushed the Sahara

desert south, destroying farmland. It had a major impact on many countries including Nigeria, Niger

andMali.

Now, scientists from the Nasa Goddard Space Flight Centre and the University of California in Los

Angeles believe it could all be explained by natural phenomena. The researchers produced a

computer model that included ocean surface temperature, the amount of moisture in the soil, and

loss of vegetation. With all those conditions, the computer model behaved just like the Sahel

drought - producing a long period of dry, cool weather.

It appears that human activity might not have been to blame for the drought, and the study suggests

the Sahel region may be naturally prone to such large climate changes. The challenge now is

whether that information will help scientists predict when the next drought is likely to occur.

EFFECTS

y AGRICLTURAL:

- The rain shortage has killed many of the crops and left people with very bad harvests

and so the food has had to be rationed.

- The rain shortage has killed many of the crops and left the lack of water is killing off the

animals which they have to use to get food and money by selling them. People are

having very bad harvests and so the food has had to be rationed.

- Agricultural bases of 5 countries crumbled (Ethiopia, Sudan, Mali, Niger and Chad).



-SOCIAL:

-The Sahel witnessed some of its most serious climate induced food shortages in 1972-

'74 and 1984-'85. Up to 250,000 drought-related human fatalities occurred throughout

the Sahel region between 1968 and 1973.

-People have had to travel up to 4km to find the nearest watering hole

- Approximately half the individuals in the Sahelian region took flight from their rural

communities to more developed urban centres

- ENVIRONMENTAL:

- The lack of vegetation has meant the animals have had to eat the leaves from the trees.

These leave the ground with no shade and so all of the vegetation underneath die of.

- The trees also slowly die off, these trees usually retain some moisture so with out them

the ground is drying up even quicker.

- The soil is then left open to the wind, the wind blows the top soil away and creates

desert, when it eventually does rain the top soil is just washed away. The soil that is left

behind is worked for the crops that it can produce, the only problem is that the soil

eventually becomes over worked and turns into desert.

- The whole place is slowly becoming a desert, this is often known as DESERTIFICATION.

- ECONOMIC:

- It hindered economic development in this region, limiting investment in the respectivenations.- Additionally, national governments of this region lost nearly 3% of their tax revenuefollowing the drought.

- On an individual level, Chad, for instance, had a per capita GNP of US$120, one of thelowest in the world

MANAGEMENT

There are 4 main ways to manage drought in LEDCs.

1) Reducing demand Hosepipe bans, paying for consumption of water (meters), publiccampaigns and educating people about how to use water during droughts.

2) Water collection/ distribution Use bunds, lines of stones etc. to collect water, fit pumps

or dig new wells, communally owned facilities, help from international aid

3) Adapting farming techniques- change from nomads to cultivators,use naturally drought

resistant crops, and use intermediate/out-dated level technology from aid resources

4) Recycling/ Conserving water collect and store any rain water underground until the dry

season, separate clean and reusable water

- In this particular drought, government response was limited for a multiplicity of factors - mostrelated to monetary reasoning. Economies in the Sahelian region at the time were not verydeveloped, thus it prevented adequate assistance to afflicted individuals and starvingcommunities.

- Additionally, with droves of people entering the urban centers seeking refuge, overcrowdingbecame an immense problem which went unresolved by national governments of the region.This inability to address overcrowding led to the proliferation of diseases like malaria.

- In terms of response to the physical occurrence, governments of Chad, Ethiopia and Niger dug channels from urban centers to rural farmlands in an effort to diffuse water, but theseefforts failed as the sweltering heat in the region limited progress of the channels'development and their effectiveness.

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