310 likes | 603 Views
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. Necessity of Water.
E N D
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
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
Water Use in the Ancient World Nileometer at Aswan
Waterwheel on the Rio Guadalquivir, Cordoba (circa 1000 AD)
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
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
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
GROUNDWATEROutside 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
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
Potential to use aquifer to treat, store and recover recycled water (source: The Weekend Australian July 6 – 7, p.18)
Australian Water Use • Irrigation 74% • Rural purposes 8% • Urban and industrial usage 18% • Primary resources are ground and surface water
Urban Water Demand • Residential use constitutes 40 – 60% • Commercial use • Industrial use • Public use • Loss
Factors Affecting DemandWater demand is based on population size but other factors may include:
Fluctuations in Demand • Diurnal flows • Seasonal flows • Maximum:minimum flows will depend on population mix
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)
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
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
A typical water supply system
Dam Water Storage Revelstoke Dam British Columbia