Water last minute Flashcards
(24 cards)
What is Eutrophication?
Eutrophication is the process where excessive nutrients enrich aquatic ecosystems.
This can lead to algae blooms, which block sunlight, disrupt the ecosystem, and ultimately deplete oxygen levels, potentially causing “dead zones” where few organisms can survive.
FROM FLOODING.
What are floodplains?
Floodplains are natural natural stores of flood water and self-regulating defences
Channelisation?
Channelisation adds a liner to a straightened river channel (usually concrete) to reduce friction which aims to improve flow rate and therefore, reduce silting
However, the method displaces the river flow downstream (increased silting or flooding) overwhelming locations during peak discharge
Dams / Floodwalls?
Dams, floodwalls and reservoirs are built to prevent flooding and ensure a regular supply of water
Unfortunately, the flow of sediment is halted and the reservoir gradually fills with silt
Downstream, erosion is increased in the river bed as they are starved from a sediment supply.
River Straightening?
River straightening increases the flow of water by increasing the gradient of a river’s channel and removing natural meanders (bends)
Increasing flow velocity, increases risks of flooding downstream if blockages occur or narrowing of the channel through an urban area
how does over grazing / ploughing cause floods?
Over Grazing = loss of vegetation = less interception and transpiration
Over Ploughing = compact soil = less porous = less infriltration.
3 Main Causes of Meteorlogical Flooding?
Intense Storms: High rainfall over a short time → short lag time → flash floods.
Prolonged Rainfall: Sustained rainfall (e.g. monsoons) saturates soil → increased surface runoff.
Snowmelt: Rising temperatures melt stored snow → sudden increase in water input to the basin.
Impact of Climate Change on Precipitation?
Warmer air holds more water, therefore, there would be an increase in rainfall frequency and intensity; areas most affected would be the tropics and high latitudes
Decreases in precipitation would most likely lie between 10° and 30° north and south of the Equator
Increased frequency and length of heatwaves, increasing occurrences of drought and water scarcity
Snowfall is replaced with rain in northern regions, reducing glacier mass
Impact of climate change on soil moisture?
Where areas see an increase in precipitation then it would follow that soil moisture will increase also and vice versa
Overall impact of climate change is uncertain as many factors contribute soil moisture levels and climate is just one factor
Impact of climate change on Evapo-transpiration
Increased evaporation over large land masses such as North America and Asia
Transpiration levels would alter inline with vegetation changes (increase or decrease), this would further link to changes in soil moisture and precipitation
Impact of climate change on ENSO?
ENSO cycles result in both extreme flooding and drought in different parts of world at the same time
However, if land and sea surface temperatures continue to rise, then it is possible ENSO cycles could become more frequent rather than every 2-3 years
This would lead to more periodic unusual climates for both South America and Australia
It would also lead to unreliable patterns of rainfall and failure of monsoons impacting many tropical monsoon climates (India etc.)
UN estimates WHAT about water stress?
It is estimated by the UN that by 2028 over 65% of the world’s population could be living with water stress
An estimated 30% of groundwater systems are being depleted
Cost of Water in Africa Case Study?
In Ghana, only 41% have access to a safely managed water source, while only 18% have access to very basic sanitation.
UK COST = 5p for 50 litres
GHANA COST = Satchet / bottled water as pipes are too expensive / limited - cost of 50L = £4
What is economic scarcity?
Economic scarcity occurs when there is water available but the infrastructure is not available to access the water
About 1.6 billion people face economic water scarcity
What is physical scarcity?
Physical scarcity occurs when there is greater demand for water than there is supply
An estimated four billion people face severe water scarcity for at least
Human and Physical impacts of water insecurity:
- Physical - variation in climate, salt water encroachment (sea level rise)
- Human - over-abstraction, water contamination, industrial pollution
Define Over Abstraction?
Over-abstraction occurs when more water is taken than is naturally replaced by precipitation
- Jakarta and Beijing are sinking as a result of past over-abstraction of groundwater which is causing subsidence
Over-abstraction from lakes and rivers is also an issue
Increased abstraction of water from the Nile by Ethiopia is decreasing the availability of water for Sudan and Egypt
How many people live without sanitation?
- Over 2.4 billion people live without sanitation
A lack of sanitation is one of the leading causes of water contamination
In developing countries 90% of sewage flows untreated into water sources
China industrial water pollution stat?
It is estimated that 80% of China’s groundwater is polluted
3 HARD ENGINEERING TO INCREASE WATER SUPPLY?
Water transfer schemes - China South to North - Bejing.
Mega dams - 3 gorges
Desalination plants - Saudi 75% of their water
Sustainable schemes to deal with water supply / conservation?
- Smart irrigation- replace traditional irrigation methods of sprinklers and surface flows with automated spray technology and drip irrigation systems
- Rainwater harvesting - precipitation is collected from roofs and stored in water butts for repurposing in toilets and watering gardens
- Restoration of damaged lakes, rivers and wetlands to return them to their part in the natural water system
- Filtration - sophisticated systems are used to remove even the finest particulates from dirty water, rendering it safe to drink again
Case Study for smart Water Supply / Conservation
Singapore has very little natural water resources and have made water management one of its priorities for its 6 million residents
- Collect all water - government educates its citizens on using water carefully and since 2006, domestic water consumption has fallen by 24 litres per person per day
- Re-use water - Singapore has cutting edge technology to re-use its grey-water called NEWater
- Desalinate - Singapore now has 5 desalination plants meeting up to 25% of demand
What is IRBM?
Integrated Drainage Basin Management
Integrated river basin management (IRBM) is the process of coordinating conservation, management and development of water, land and related resources across sectors within a given river basin, in order to maximise the economic and social benefits derived from water resources in an equitable manner while preserving and, where necessary, restoring freshwater ecosystems.
IWRM is successful at a local, community level, but not at national or international levels
