Hydraulics and Hydrology Lec

48362 HYDRAULICS and HYDROLOGY James E Ball Hydrology Component win enlarge 1 CONTACTS ? Assoc Prof James Ball ? ? ? james. emailprotected edu. au ph 9514 2623 Office Hours ? ? Monday 200 400pm Contact by email for appointment SUBJECT model The objective of this component of the subject is ? Introduce engineering hydrology ? Introduce hydrological processes ? Introduce flood estimation and ? Introduce engineering hydrology applications in water resources management. 2 SUBJECT CONCEPT This introduction is aimed at ? Providing an ability to apply commonly used methods in hydrology and ?Provide an understanding of the theory behind these methods. REFERENCES Three references that may be useful are ? Applied Hydrology Chow, Maidment & Mays, McGraw-Hill Book Co. ? Hydrology An Australian Introduction Ladson, Oxford University Press ? Australian Rainfall & Runoff A Guide to Flood Estimation Engineers Australia No published Course Notes are available for this subject. 3 SUBJECT DO CUMENTS UTS-Online will be used for distribution of ? Copies of lecture slides ? Reading material and ? Tutorial problems. Students should tincture that additional reference books may be noted in the lecture slides.LECTURE STRUCTURE Each Hydrology lecture period will comprise ? 2 moment lecture and ? 1 hour tutorial. It is expected that students will have accessed the lecture slides, reading material and tutorials prior to the lecture period. 4 SUBJECT TIMETABLE Date effect 27 February Hydrology and Water Resources 5 March Meteorology 12 March Hydrologic Data 19 March Surface Water 27 March wedge Runoff 2 April Hydrologic bod 9 April Design Rainfall 1 May Peak Flow Estimation 7 May Hydrograph Estimation come apart 1 13 May Hydrograph Estimation Part 2 14 May Environmental Flows 21 May Water Sensitive Urban Design 4 JuneCourse Review HYDROLOGIC beat Lecture 1 5 CONTENT ? Introduction to Hydrology ? Development of Hydrology ? Hydrologic Cycle ? Australian Hydrology INTRODUCTI ON 6 DEFINITION OF HYDROLOGY classical word Hydor = water & ology = study of Hydraulics comes from Greek word hydraulikos which in turn comes from hydor (Greek for water) and aulos (meaning pipe). DEFINITION OF HYDROLOGY UNESCO (1979)1 defines hydrology as the physical science which treats the waters of the Earth, their Occurrence, Circulation and Distribution, their Chemical and carnal Properties, and their Reaction with the Environment. UNESCO, (1979), Impact of urbanisation and industrialisation on water resources planning and management, Studies and Reports in Hydrology, UNESCO, UNESCO, Paris. 7 piddle Water is essential for maintenance of life. aboriginal civilisations were concentrated on rivers ? ? establishment of settlements near rivers analogous to looking for signs of water on Mars Management of water is multi-disciplinary many professions are involved. WATER variety of problems encountered include ? Flood mitigation ? Sanitary sewer systems ? Land drainage ? Water S upply ? Culvert and bridge design ? Environmental Flows ? Erosion ?Mine tailings ? drought ? Adaptation to climate change ? Irrigation systems ? Hydro-electric and power generation ? Stormwater systems 8 RURAL FLOODING URBAN FLOODS 9 STORMWATER STRUCTURES STORMWATER DRAINS 10 WATER SUPPLY HYDRO-ELECTRIC POWER 11 IRRIGATION SCHEMES DROUGHT 12 DEVELOPMENT OF HYDROLOGY Ancient civilisations were integrated with their river valleys. Examples are ? ? ? ? ? Egyptian Civilisations and the Nile Valley Mesopotamian Civilisations and the TigrisEuphrates Indian Civilisations and the Indus Valley Ancient China and the Yellow River Andean Civilisations and coastal Peru DEVELOPMENT OF HYDROLOGYMany of structures from early civilisations are still in operation. Large scale irrigation and drainage works were associated with these civilisations. Earliest recorded dam is about 2900BC (the Sadd Al-Kafara at Wadi Al-Garawi, 25km southern of Cairo) apply for both flood protection and irrigation. Also site of earliest known dam failure. 13 DEVELOPMENT OF HYDROLOGY Oldest surviving dam in the creation is the Grand Anicut Dam on the Kaveri River in Southern India. This structue dates back to 2nd Century AD. DEVELOPMENT OF HYDROLOGY Water supply to Ancient Rome has been estimated as being approx 500L/c/d.Current water supply requirements are ? ? ? Australian cities, design approx. 430L/c/d Australian cities, actual approx. 230L/c/d US cities, design approx 600L/c/d Drainage structures (such as the Cloaca Maxima) from Ancient Rome are still being used today. 14 ANCIENT ROMANS Cloaca maxima Bath, UK AQUEDUCTS Pont du Gard, France c19 BC Hampi, India beginning(a) century AD 15 DEVELOPMENT OF HYDROLOGY Flood protection has been practiced for thousands of years along the Yellow and Yangtze Rivers. It mud an issue of concern in these demesnes to the real day. DEVELOPMENT OF HYDROLOGY Water has been of interest for many years.Ancient Greek and Roman philosophers speculated on a h ydrologic cycle Homer, Plato, Aristotle, Lucretius, Seneca, Pliny. This cycle was developed from their observations of water in their environment. Use of observations remains a fundamental component of current hydrologic applications and research. 16 DEVELOPMENT OF HYDROLOGY Chinese recorded observations of rain ? ? ? An-yang oracle bones as early as 1ccBC Used rain gauges around 1000BC and Established systematic records about 200BC. Indian records date back to 400BC. DEVELOPMENT OF HYDROLOGY Scientific culture of hydrology occurred uring the Renaissance period. Examples are ? ? ? Leonardo da Vinci velocity distributions in streams. Bernard Palissy springs originated from pelting. Pierre Perrault runoff is a fraction of rainwater. 17 DEVELOPMENT OF HYDROLOGY Other contributions during this period were made by ? ? ? ? ? Galileo spick-and-spanton Bernoulli Euler Lagrange DEVELOPMENT OF HYDROLOGY world-shaking scientific development occurred in the 19th Century when ? ? ? ? ? D alton proposed the principle of evaporation. Hagen-Poiseuille described capillary flow. Mulvaney developed the Rational method. Darcy described mathematically porous media low. Rippl developed methods for ascertain storage requirements. 18 DEVELOPMENT OF HYDROLOGY 20th Century saw rapid development of quantitative hydrology. Biggest influence during this period was the development of the digital computer and the development of catchment modelling systems. Limitation now is data availability rather than calculation capacity. HYDROLOGIC CYCLE 19 HYDROLOGICAL CYCLE One of the fundamental cycles of nature. Basis for the science of hydrology. weighty points ? ? ? ? Cycle has no start and no end. Cycle is continuous. Flow of water in the cycle is not continuous.Water moves erratically through the cycle. HYDROLOGICAL CYCLE 20 HYDROLOGICAL CYCLE HYDROLOGICAL CYCLE 21 HYDROLOGICAL CYCLE HYDROLOGICAL CYCLE General components of the cycle are ? Atmospheric Water ? Surface Water ? Ground Wate r In analysis of water resource problems, these components are treated with a systems approach. 22 SYSTEMS CONCEPT A systems concept is applied when considering the hydrological cycle or some component thereof. This is reconciled with the reductionist concept used in many engineering problems. SYSTEMS CONCEPT The reductionist philosophy is based on reducing the system to a scrap of smaller omponents. The response of the system then is determined from summation of the responses of the individual components. 23 SYSTEMS CONCEPT WATER BALANCE 24 WATER BALANCE sum total of water does not change. Where it may be found does change. Water maybe found in the seas and oceans, in the atmosphere, on the surface, below the surface, and in biological systems. WATER BALANCE ITEM nauticals gelid Ice Groundwater Lakes Soil Moisture Atmospheric Water Rivers Biological Water ?Water VOLUME (km3) % TOTAL WATER 1. 338 x 109 96. 5 24. 0 x 106 1. 7 23. 4 x 106 1. 69 187. 9 x 103 0. 0138 16. 5 x 103 0 . 0012 12. 9 x 103 . 001 2. 1 x 103 0. 0002 1. 1 x 103 0. 0001 1. 386 x 109 100. 0 UNESCO, 1978 ref 11, ladson ch1 25 WATER BALANCE Not all water is invigoratedwater. Only approx 2. 5% of the water is fresh water water in the oceans and some lake water and ground water is saline. Considering only fresh water, the values in the previous table are modify to WATER BALANCE UNESCO, 1978 ITEM VOLUME (km3) % TOTAL WATER Polar Ice 24. 0 x 106 68. 6 Groundwater 23. 4 x 106 30. 1 103 0. 26 Soil Moisture 16. 5 x 103 0. 05 Atmospheric Water 103 0. 04 Rivers 2. 1 x 103 0. 006 Biological Water 1. 1 x 103 0. 003 Fresh Water 35. 0 x 106 00. 0 Lakes 187. 9 x 12. 9 x 26 WATER BALANCE Basis of any volume based problem is a water balance. This is a usage of the concept of continuity. In general, application of continuity gives in volume terms Inflow Outflow = Change in store (? S) And in flux terms Qi Qo = ? S / ? t WATER BALANCE Components of inflow for a water body such as a lake or reservoir are ? Precipitation (P) ? Inflow from rivers or groundwater (I) 27 WATER BALANCE Components of outflow for a water body such as a lake or reservoir are ? Evapo-transpiration (ET) ? Outflows Extractions, Downstream flows, (O) and ? Seepage (G)WATER BALANCE Hence the water balance for a water body is P + I O ET G = ? S 28 WATER FLOWS While the volume of water in a source is important, the flux of water through a component is important also. An indication of the flux can be obtained from the diagram of the hydrological cycle. WATER FLOWS The Global yearbook Water Balance is shown on in units congener to the annual volume of precipitation on land masses. Note that this is a flow rate (km3/yr). 29 WATER FLOWS ? Precipitation ? ? ? ? Land 119,000 km3/yr (800mm/yr) maritime 458,000 km3/yr (1270mm/yr) bring 577,000 km3/yr Evaporation ? ? ?Land 72,000 km3/yr (484mm/yr) Ocean 505,000 km3/yr (one hundred forty0mm/yr) Total 577,000 km3/yr WATER FLOWS ? Runoff to Oceans ? ? ? Rive rs 44,700 km3/yr Groundwater 2,200 km3/yr Total Runoff 47,000 km3/yr (316mm/yr) 30 WATER FLOWS Considering the volume and flux gives the mean residence clocks in a particular source. The mean residence time for atmospheric water is obtained by dividing the volume (S) of water in the atmosphere by the flux (Q), ie TR ? S 12,900 ? ? 0. 022 yr ? 8. 2days Q 577,000 WATER FLOWS ITEM Oceans Polar Ice & Glaciers Groundwater Lakes Soil Moisture Rivers Atmosphere Biological WaterTR 2600 years 1100 years 700 years 13 years 155 days 13 days 8. 2 days 3. 4 days 31 AUSTRALIAN CLIMATE AUSTRALIAN CLIMATE of droughts and flooding rains 32 RIVER RUNOFF Australia has low runoff per unit nation (average depth of surface runoff). Also, Australian runoff has greater variability due to lack of snow melt period. RAINFALL COMPARISON Variability of Annual rain 20 18 Coefficient (%) 16 14 12 10 8 6 4 2 0 A ustralia S. A frica Germany France NZ India UK Canada China the States Russia Country 33 AUSTRALI AN CLIMATE CLIMATE CLASSIFICATIONS Marked wet summer and dry winter of northern Australia.Wet summer and low winter rainfall of southeast QLD and northeast NSW. Uniform rainfall in southeast Australia. Wet winter and dry summer of southwest WA and parts of the southeast. Arid area comprising about half of the continent More on BoM website 34 AUSTRALIAN RAINFALL Pluviometer Network Daily Read Network PRECIPITATION 35 AUSTRALIAN RAINFALL City bonnie Annual Rainfall (mm) Average Number of Rain Days Darwin 1714 111 Sydney 1217 138 Brisbane 1149 122 Perth 786 114 Melbourne 653 147 Canberra 623 105 Hobart 569 135 Adelaide 530 121 Alice Springs 279 31 later on Ladson, 2008 AUSTRALIAN CONDITIONSAustralian rainfall is influenced by general circulation patterns. Most of Australia is around 30o latitude which tend to be areas of descending air. Note that the solar equator moves during the year. 36 AUST. CLIMATE variability Known major causes Approximate time scale Effect Synoptic weather patterns Day / week Weather Southern Annular Mode Weeks +ve point = winter rainfall deficiencies in southern Australia summer increases in MDB El Nino / La Nina (Southern Oscillation Index) Inter-annual El nino = lower rainfalls La nina = higher rainfalls Indian Ocean Dipole Inter-annual ve phase = increased rainfall +ve phase = decreased rainfall Inter-decadal Pacific Oscillation Inter-decadal Flip flops between drier and wetter periods e. g. 1st half of 20th century wetter than 2nd half The Australian climate influences http//www. bom. gov. au/watl/about-weather-and-climate/australian-climate-influences. html 37 The Australian climate influences The Australian climate topography 38 Seasonal rainfall variation across the country Seasonal rainfall variation across the country Mean rainfall Katherine mm Mean rainfall Dubbo mm 240 220 200 180 one hundred sixty 140 120 100 80 60 40 0 0 240 220 200 180 160 140 120 100 80 60 40 20 0 J F M A M J J A S O N J D F Mean rainfall Alice Springs mm M A M J A S O N D Mean rainfall Sydney mm 240 220 200 180 160 140 120 100 80 60 40 20 0 J 240 220 200 180 160 140 120 100 80 60 40 20 0 J F M A M J J A S O N D J F M A M J J A S O S O N N D Mean rainfall Perth mm Mean rainfall Strahan mm 240 220 200 180 160 140 120 100 80 60 40 20 0 J F M A M J J A S O N D 240 220 200 180 160 140 120 100 80 60 40 20 0 Perth wind rose February J F M A M J J A D Rainfall variability a comparison Annual rainfall Birdsville mm 600 400 200 2000 1980 1960Annual rainfall Bourke mm Annual rainfall Perth 1940 1920 1900 0 mm 1000 1400 1200 800 1000 600 800 600 400 400 200 200 1980 1960 1940 1920 1900 1980 1960 1940 1920 1900 1880 1880 0 0 39 NSW annual rainfall time-series New South Wales Annual Rainfall 1000 900 Dry Period 1900 1946 Average Rainfall 477. 7mm *Dry conditions commenced 1890 Standard Deviation 90. 4 Wet Period 1947 2000 Average Rainfall 573. 9mm 20. 1% increase Standard Deviation 127. 0 800 New Dry 2001/06 439. 5mm 23. 4% d ecline Rainfall (mm) 700 600 500 400 300 200 100 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Year 40