chapter 1 Flashcards
water scarcity
either the lack of enough water (quantity) or lack of access to safe water (quality).
economic scarcity
finding a reliable source of safe water is often time-consuming and expensive
physical scarcity
lack of water
hydrological cycle
renews the world’s freshwater resources through evaporation and precipitation.
average amount of ppn, evaporated part and remains part, etc.
Average annual precipitation on land: 110 000 km3 Evaporated part: 70 000 km3 remains: 40 000 km3 relatively stable supply: 14 000 km3 Global freshwater consumption: 4 000 km3
The 40 000 km3 of available water are distributed very unevenly and two-thirds of it….
runs off in floods
For example, 6 000 km3 of water is needed to dilute and transport the estimated ……… of waste water now entering the world’s rivers each year.
450 km3
Without ………………………. even more water will have to be diverted to dilute and transport wastes.
substantial investment in waste water treatment and more effective regulation,
Human actions bring about water scarcity in three ways:
through population growth misuse nequitable access.
average annual flow
Every country has a more or less fixed amount of internal water resources, defined as the average annual flow of rivers and aquifers generated from precipitation.
When annual internal renewable water resources are less than 1 000 m3 per caput, water availability is considered
a severe constraint on socio-economic development and environmental protection.
Most countries facing chronic water scarcity problems are in
North Africa the Near East sub-Saharan Africa.
serious water shortages are causing difficulties in
specific regions and watersheds.
examples of water shortages
northern China western and southern India parts of Mexico
People also bring about water scarcity by
polluting and overusing existing supplies.
If pumping is greater than recharge…
the aquifier is depleted and the capital is consumed
Precipitation …………
absorbs gases from the atmosphere and removes particles from the air.
When the precipitation strikes the ground it
becomes surface water runoff or enters the ground.
The surface water flows into
larger and larger channels, ponds, lakes and rivers until some of it reaches the sea.
surface water picks up
both organic and mineral particles, bacteria and other organisms as well as salts and other soluble substances.
The water in lakes and swamps sometimes acquires
odours, tastes and colours from algae and other organisms and from decaying vegetation.
heavy metals from mining and pathogens from cities have caused serious, although localized, …………..
contamination
localized contamination is caused by
heavy metals from mining and pathogens from cities
Much water is polluted when it is used in
industry and agriculture or for domestic purposes.
Mining is the major cause of
metal contamination
industries contribute to
acidification
The intensification of agricultural activities has led to
the contamination of groundwater by fertilizers and other chemicals
irrigation projects often cause
a rapid rise in the level of groundwater, which leads to waterlogging and soil salinity.
Recent assessments have found that the main water pollutants are:
sewage, nutrients, toxic metals and industrial as well as agricultural chemicals.
the most common water pollutant is
organic material from domestic sewage, municipal waste and agro-industrial effluent; and the high water nitrate levels
the high water nitrate levels found in
Western Europe and the United States
the high water nitrate levels are a result of
the nitrogen fertilizers and manure used for intensive agriculture
Deforestation
the clearing of land for agriculture and urban development, often leads to water contamination
Eutrophication
the enrichment of waters with nutrients, especially phosphorus and nitrogen
Salinity
significant and widespread form of freshwater pollution, particularly in arid, semi-arid and some coastal regions.
Cause of salinity
combination of poor drainage and high evaporation rates which concentrate salts on irrigated land.
Waterlogged soil
which aggravates the problem of salinity, is usually caused by overwatering and a lack of proper drainage systems.
Overuse of groundwater has become a major problem in
China,
India,
Indonesia,
Mexico,
the Near East,
North Africa,
Thailand,
the western United States
and many island countries where seawater intrusion results.
The overpumping of aquifers result in
- water source that is too depleted to serve as a supply
- cause the land above the aquifer to settle or subside, resulting in widespread structural damage in extreme cases
countries that surve an example of the dangers of overpumping
Bangkok and Mexico City
agriculture water use persentage
70%
Domestic and industrial water use persentage
30%
Domestic water uses include
drinking-water supplies, private homes, commercial establishments, public services and municipal supplies.
Poor families in some large cities spend up to percent of their income on water.
20
When the cost is so high, they use little water for washing and bathing, which results in
serious health problems
Countries predicted to have scarce water resources
Egypt
Saudi Arabia
Libya
UAE
Jordan
around 15 000 m3 of water are normally sufficient to irrigate 1 ha of rice. This same amount of water can supply:
100 nomads and 450 head of stock for three years;
or 100 rural families through house connections for four years;
or 100 urban families for two years;
or 100 luxury hotel guests for 55 days.
Domestic water demand is …………………in comparison with agriculture and industry
moderate
Domestic water quality requirement is
high
Domestic and municipal water uses include
drinking, washing, food preperation and sanitiation
Two of the most troubling domestic water supply issues for policy-makers are
access and health
Health officials identify five categories of disease related to water:
i) water-borne diseases (typhoid, cholera, dysentery, gastroenteritis and infectious hepatitis);
ii) water-washed infections of the skin and eyes (trachoma, scabies, yaws, leprosy, conjunctivitis and ulcers);
iii) water-based diseases (schistosomiasis and guinea-worm);
iv) diseases from water-related insect vectors such as mosquitoes and blackflies; and
v) infections caused by defective sanitation (hookworm).
Explain the concept of resource geopolitics or “hydropolitics”
The increasing value of water,
concern about water quality and quantity,
and problems of access and denial
have given rise to the concept of resource geopolitics or “hydropolitics”.
give examples of countries that receive over 75 percent of their available water supplies from the river flows of upstream neighbors.
Botswana,
Bulgaria,
Cambodia,
the Congo,
Egypt,
the Gambia,
Hungary,
Luxembourg,
Mauritania,
the Netherlands,
Romania,
the Sudan
and the Syrian Arab Republic
over ………….percent of their available water supplies from the river flows of upstream neighbors.
75
More than percent of the world’s population lives in river basins that are shared by more than one country.
40
