GEOG10001 Lecture Notes - Lecture 17: Phreatic Zone, Interbasin Transfer, Waterborne Diseases
16 May 2018
School
Department
Course
Professor
LECTURE 17: HYDROLOGY + WATER QUALITY
• Famines: many deaths linked to disease from water + water availability (not just food)
• Projected climate change: wet areas wetter, dry areas drier, coastal flooding = salt water invasion, higher temps leading to drought,
+ breakdown of water storage + management infrastructure
o Increased fractions of the population will experience water scarcity or flood
FRESHWATER
Sources
• Water bodies: rivers, lakes, wetlands, estuaries
• Groundwater – largest freshwater source for populated continents!!!!!
• Hyporheic Zone: interchange between surface + groundwater – quality of each affects the
other
• Atmospheric Water
• Frozen: ice, glaciers, ice caps etc.
Rivers
International River: a river that forms a boundary between 2 or more nations, results in conflict
because of river change
Transnational River: a river that flows across international boundaries, management coordination needed
• River continuum concept: headwater – transfer – deposition
o Rivers can be controlled + managed to store (dams), change flow + sediment = changed water quality
Groundwater (also known as phreatic zone)
Precipitation that enters the water table, saturated
• Needs to be managed, yet we have limited knowledge on it
• Does not adhere to state boundaries, nor to catchment boundaries
• Phreatic Zone: permanently saturated, aquifer the main type
o Not all groundwater within this zone the same, have different recharge + flow rates
o 2 types of aquifer: open, and confined (no flow, water tapped into – artesian well)
• Where developing countries pump deeper into groundwater in times of scarcity, they are using water
with slow recharge rates, and will deplete all resources
• Saline Intrusion: occurs after depletion of groundwater + due to rising water table after land clearing
o Leads to intrusion of contaminated water
Basic Supply Sources
Source
Description
River
• Intakes difficult to design, weirs used moderate sized rivers, don’t work for large rivers
• Affects sediment and environmental flows
• Reservoir: built with gravity feeding system OR run of river supply
Groundwater
• Costs associated with pumping (fuel needed), could lead to salt water intrusion
• Not a finite resource – often slow recharge rate
• Different chemistry to surface water
• Available all year
Other River
• Interbasin transfer schemes
• Pumping costs to get through tunnels or catchment divides
• Allows redistribution from wetter areas or larger rive systems
• Also transfers ecology + physical pollutants (temp, chemicals, sediment)
• Differing water resources can be managed together
• Aim: optimise river resources through seasons based on price, determine what water source is used
• River =cheap, reservoirs = medium, groundwater = expensive
o However, negatives: maximising cheap river water = leaves dry, lack of co-ordination between source management +
dams have different physical condition
WATER QUALITY
• Multiple ways to measure quality
o Can be based on humans and/or biota
o Eg. turbidity, dissolved oxygen, nutrients
• Main point: safe level of chemicals
Waterborne Pathogens
Pathogen: bacterium, virus or micro-organism that can cause disease
• Most waterborne pathogens:
o Introduced into drinking-water supplies in human or animal faeces
o Don’t grow in water, grow inside the host
o Initiate infection in gastrointestinal tract following ingestion
• Examples: typhoid, cholera, cryptosporidium, diarrhoea
• Waterborne diseases play an important role in understanding famine mortalities
Reducing risk
• Groundwater preferred = higher quality
• Surface water + groundwater interactions increase risk – associated with poor sanitation
o Build structures around wells or locate in further away areas to ensure contaminated surface water does not degrade
quality of sourced ground water
Catchment
• Unit of management in Aus
• Water should be managed
at a catchment scale
• Includes: source, tributary +
mouth
• The area of which rain falls
and enters the river system
• Divided by topography
• Can be altered by land use
change
In a famine resource scarcity situation – lower water quality may be accessed
Groundwater has
various residence
times, need to be
considered in
management +
use of the resource
Document Summary
Famines: many deaths linked to disease from water + water availability (not just food) Projected climate change: wet areas wetter, dry areas drier, coastal flooding = salt water invasion, higher temps leading to drought, + breakdown of water storage + management infrastructure. Increased fractions of the population will experience water scarcity or flood. Sources: water bodies: rivers, lakes, wetlands, estuaries, groundwater largest freshwater source for populated continents!!!! Hyporheic zone: interchange between surface + groundwater quality of each affects the other. International river: a river that forms a boundary between 2 or more nations, results in conflict because of river change. Transnational river: a river that flows across international boundaries, management coordination needed. River continuum concept: headwater transfer deposition. Unit of management in aus: water should be managed at a catchment scale. The area of which rain falls and enters the river system. Divided by topography: can be altered by land use.
