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SOURCE AND DISTRIBUTION OF WATER On completion of this segment you should be able to appreciate

• Water, an essential component

• Sources and application of water resources

• Distribution of global water

• Uniqueness of water in Australia and its water demand

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Necessity of Water

• Water is fundamental to life

• Water is used not only for drinking but power, transport and irrigation

• Ancient civilisations thrived where water was abundant or learned to harness it

• Contaminated water led to outbreaks of diseases

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Water Use in the Ancient World

Nileometer at Aswan

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Waterwheel on theRio Guadalquivir,Cordoba(circa 1000 AD)

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World Water Crisis

• Water is life’s most precious resource

• An estimated 1.4 billion people lack safe water

• 3.3 billion cases of illness and 5.3 million deaths per year

• 2/3 of humanity will face shortages in 2025

• Knowledge is central to improve global water supply

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Distribution of Global Water

Distribution %Fresh water

(2.5%) distributedas

Soil & surfacewater (0.5%)distributed as

Oceans, seas

Fresh water

97.5

2.5

Ice caps

Groundwater

Soil & surface

76.0

23.5

0.5

Lakes

Soil moisture

Atmosphere

54.0

38.0

8.0

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Comparison of World’s Drainage Systems

Drainage system Billion m3

Yangtze 1088

Brahmaputra 599

Mississippi 568

Danube 202

Fly 189

Rhine 69

Murray-Darling 24

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Queensland’s Major Drainage Systems

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Uniqueness of Australian Water Resources

• Average annual precipitation is 465 mm of which 10% appears as runoff

• Average annual world precipitation is 860 mm

• Wide disparity in temporal and spatial distribution

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Wide disparity in temporal distribution

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Wide disparity in temporal distribution

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Wide disparity in temporal distribution

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SURFACE WATERThe most visible water resource resulting from excess rainfall that appears as streams and lakes

• Quality and quantity are highly variable

• Requires storage

• Subject to changing land use and evaporation

• Runoff and precipitates may add significant contaminants

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GROUNDWATER

Outside ice-caps and glaciers (76.0%), groundwater represents a significant part of global freshwater (23.5%), while surface water is only minute (0.5%)

• Small development cost

• Negligible evapotranspiration losses

• Reduced alienation of productive land

• Consistent water quality

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GROUNDWATERSome disadvantages:

• High pumping energy cost

• Variation in standing water level

• Higher dissolved solids and minerals

• Corrosion and encrustation of pipes and fittings

• May not be suitable for human and industrial uses

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Potential to use aquifer to treat, store and recover recycled water

(source: The Weekend Australian July 6 – 7, p.18)

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Australian Water Use

• Irrigation 74%

• Rural purposes 8%

• Urban and industrial usage 18%

• Primary resources are ground and surface water

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Urban Water Demand

• Residential use constitutes 40 – 60%

• Commercial use

• Industrial use

• Public use

• Loss

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Some water supply planning parameters

Average Day Demand

ADD Total annual demand/365 day

Mean Day Max Month

MDMM Highest 30 day moving average daily water demand

Peak Day Demand

PD Maximum day demand

Peak Hour Demand

PH Maximum hour demand or peak instantaneous demand

Fire flow 15 L/s for 2 h in residential; 30 L/s in commercial; also dependent on population

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Factors Affecting DemandWater demand is based on population size but other factors may include:

Climatic conditions Sewerage & drainage Water quality Pressure and flow Topography, soil types Water restriction Metering Availability Lot size, gardening

interest

Affluence and costs

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Fluctuations in Demand

• Diurnal flows

• Seasonal flows

• Maximum:minimum flows will depend on population mix

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Ratio Peak:Average Flow Against Population

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Some factors used in the Design Flow

• Average daily demand (ADD)

• Mean day of the max month (MDMM = 1.5 x ADD)

• Maximum day (PD = 1.5 x MDMM)

• Maximum hour (PH = MD/12)

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Queensland average flows

• 400 L/c.d in SE Queensland

• 800 L/c.d in northern coastal towns

• 1500 L/c.d in dry western areas

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A Water Supply System

• Source - surface, ground or combination

• Extraction facilities - intake structures, pumps

• Conveyance system - trunk mains, channels

• Water treatment to achieve quality

• Distribution system - storage, supply mains and reticulation

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A typical water supplysystem

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Dam Water Storage

Revelstoke DamBritish Columbia

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An Intake Structure

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An Intake Structure (Perseverance)

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A Small Intake Structure

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End of water source and demand segment