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ERT 246 HYDROLOGY AND WATER RESOURCES ENGINEERING PowerPoint Presentation
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ERT 246 HYDROLOGY AND WATER RESOURCES ENGINEERING

ERT 246 HYDROLOGY AND WATER RESOURCES ENGINEERING

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ERT 246 HYDROLOGY AND WATER RESOURCES ENGINEERING

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  1. ERT 246 HYDROLOGY AND WATER RESOURCES ENGINEERING Ms Siti Kamariah Bt Md Sa’at School of Bioprocess Engineering sitikamariah@unimap.edu.my

  2. Text Book • Bedient B. P; Huber W.C and Vieux B.E,. (2008) Hydrology & Floodplain Analysis, 4th Ed. Prentice-Hall, Inc, Upper Saddle River, NJ 07458

  3. Reference Books • Subramaya K.(2008),Engineering Hydrology, 3rd Ed. McGraw Hill,New York,N.Y • DID. (2000), Urban Stormwater Management Manual for Malaysia, DID, Malaysia • V.T. Chow, D.R. Maidment and L.W. Mays (1988,) Applied Hydrology, McGraw-Hill

  4. Course Objectives At the end of the course, students are expected to be: • 1. EXPLAIN and DISCUSS components of hydrologic cycle. • 2. Ability to DEMONSTRATE use of , ASSESS, and PERFORM, techniques of hydrologic analyses. • 3. ANALYZE and ASSESS hydrologic data for engineering design and management

  5. INTRODUCTION

  6. What is hydrology • From Greek word “hudor” means water and “logy” means research. • The science dealing with all aspects of the waters of the Earth. • Water is essential for all living things. It also participates in the physical and geochemical evolution of most nonliving matter on Earth • Its adequate supply is a key factor for urban, agricultural, and industrial development

  7. What is hydrology • Deals with occurence,circulation, storange and distribution of surface and ground water on earth • Relates to water quality and quantity • Hydrologic cycle and process • Water resources management • To solve human problem related to water such as flood, water supply

  8. Hydrology and Water Resources Engineering

  9. Hydrology and Water Resources Engineering

  10. History of Hydrology - 1800s • Chezy Channel Formula in the 1780s • Open channel flow experiments - 1800s • US Army Corps of Eng established (1802) • Darcy and Dupuit laws of ground water - 1850s • USGS first measured Miss River flow in 1888 • Manning’s Eqn - Open Channel Flow - 1889 • U.S. Weather Bureau 1891 (NWS) • Major Hurricane at Galveston - 1900 (8000 dead)

  11. History of Hydrology - 1900s • Early 1900s saw great expansion of water supply and flood control dams in the western U.S. - in response to Dust Bowl and the Great Depression of the 1920s & 30s • U.S. Dept of Agriculture began many hydrologic studies • Sherman UH and Horton infiltration theory - mid 1930s • U.S. Army Corps of Engineers (1930s) - large projects • Major Hurricane at Florida - over 2000 deaths • Penman (1948) - complete theory of evaporation

  12. Important of water • The most important resources after oxygen. • Minimum requirement for human= 1.5L/d • Plants also need water for photosynthesis and nutrient transport • Human civilization such as Nile River, Hwang Ho River, Klang River • Water related problem

  13. Problems in Hydrology • Extreme weather and rainfall variation • Streamflow and major flood devastation • River routing and hydraulic conditions • Overall water supply - local and global scales • Flow and hydraulics in pipes, streams and channels • Flood control and drought measures • Watershed management for urban development

  14. Total water in the world = 1.36 x 1018 m3

  15. What percent of the Earth’s total volume of water is stored in the atmosphere? • 0.001% • Water vapor • Clouds (water vapor condensed on particulate)

  16. Major Hydrologic Cycle Processes • Precipitation • Evaporation or ET (loss to atmosphere) • Infiltration (loss to subsurface soils) • Overland flow (sheet flow toward nearest stream) • Streamflow • Ground water flow and well

  17. The Hydrologic Cycle

  18. Atmosphere

  19. What two processes change liquid water into vapor that can ascend into the atmosphere? • Evaporation 90% • Transpiration 10% What percent of the water in the atmosphere comes from evaporation?

  20. Evaporation • The process by which liquid water is transformed into a gaseous state • Evaporation into a gas ceases when the gas reaches saturation

  21. Evaporation v. Precipitation • About equal on a global scale • Evaporation more prevalent over the oceans than precipitation • Over land, precipitation exceeds evaporation • Most water evaporated from the oceans falls back into the ocean as precipitation • 10% of water evaporated from the ocean is transported over land and falls as precipitation • Once evaporated, a water molecule spends ~ 10 days airborne

  22. Transpiration The process of water loss from plants through stomata. (Stomata are small openings found on the underside of leaves that are connected to vascular plant tissues.) • passive process that depends on: • humidity of the atmosphere • the moisture content of the soil • only 1 % of the water transpired used for growth • transports nutrients from the soil into the roots and carries them to the various cells of the plant • keeps tissues from becoming overheated

  23. Precipitation • The vapor that accumulates or freezes on condensation nuclei is acted on by gravity and falls to Earth’s surface. rain, freezing rain, sleet, snow, or hail primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth

  24. Meteorological factors affecting surface Runoff • Type of precipitation • Rainfall intensity • Rainfall amount • Rainfall duration • Distribution of rainfall over the drainage basin • Direction of storm movement • Precipitation that occurred earlier and resulting soil moisture • Meteorological conditions that affect evapotranspiration

  25. Physical characteristics affecting surface runoff • Land use • Vegetation • Soil type • Drainage area • Basin shape • Elevation • Topography, especially the slope of the land • Drainage network patterns • Ponds, lakes, reservoirs, sinks, etc. in the basin, which prevent or delay runoff from continuing downstream

  26. Human factors affecting surface runoff • Urbanization -- more impervious surfaces reduce infiltration and accelerate water motion • Removal of vegetation and soil -- surface grading, artificial drainage networks increases volume of runoff and shortens runoff time to streams from rainfall and snowmelt

  27. Most runoff… • Drains to a creek • To a stream • To a river • To an ocean • Rarely runoff drains to a closed lake • May be diverted for human uses

  28. Groundwater begins as INFILTRATION Precipitation falls and infiltrates into the subsurface soil and rock • Can remain in shallow soil layer • Might seep into a stream bank • May infiltrate deeper, recharging an aquifer • May travel long distances • May stay in storage as ground water

  29. How much ground water? • Ground water occurs only close to the surface (a few miles down) • Density of soil/rock increases with depth • The weight of the rocks above condense the rocks below and squeeze out the open pore spaces deeper in the Earth

  30. Outlet point Watershed • A basin, drainage or catchment area that is the land area that contributes runoff to an outlet point Watershed boundary

  31. Watersheds • We all live in a watershed! • Area of land from which all water drains, running downhill, to a shared destination - a river, pond, stream, lake, or estuary

  32. Watersheds • Area of land that drains to a single outlet and is separated from other watersheds by a drainage divide. • Rainfall that falls in a watershed will generate runoff to that watershed outlet. • Topographic elevation is used to define a Watershed boundary (land survey or LIDAR) • Scale is a big issue for analysis

  33. Functions • Captures precipitation – its characteristics influence how much is captured • Stores water once it infiltrates into soil (important to plants) • Slowly releases water into streams, rivers, oceans

  34. Why are watersheds important? • Activities within a watershed impact runoff and water quality of water leaving the watershed • Must manage at a watershed level rather than other boundaries to attain goals related to runoff and water quality

  35. Watershed Characteristics Divide Reservoir • Size • Slope • Shape • Soil type • Storage capacity Natural stream 1 mile Urban Concrete channel

  36. Watershed Shapes • Important hydrologic characteristic • Elongated Shape • Concentrated Shape • Affects Timing and Peak Flow • Determined by geo - morphology of stream

  37. Measurement and Unit • 3 types of measurement • Depth • mm,cm,m, inch, ft • Total rainfall, river depth, evaporation • Volume • cm3,m3,liter, ft3,meter hectare, km3 • Rainfall volume in tank, water requirement, ocean volume • Flowrate • L/s, L/min, m3/s • Stream flowrate, flow in pipe

  38. Units • Rainfall volume is normally measured in inches or cm • Rainfall rate or intensity in inches/hr or cm/hr • Infiltration is measured in inches/hr or cm/hr • Evaporation is measured in inches or in/hr (cm/hr) • Streamflow is measured in cfs or m3/s • Ground water flows are measured as ft3/day or m3/day

  39. Hydrological Data • Meteorological Data • Temperature, relative humidity, moisture, wind speed, sun • Data can be obtained fom JMM • Rainfall data • DID • Streamflow record • DID • Water quality record • JAS, ASMA

  40. Water Balance/Budget • dS/dt = I – O Where dS/dt = change in storage per time I = inflow O = outflow

  41. Water Balance/Budget • Input-Output = Change in storage • P-R-G-E-T = ∆S Where P = precipitation R = surface runoff G = ground water flow E = evaporation T = transpiration ∆S = change in storage

  42. Example 1 • A catchment received inflow and outflow in 10 and 15 m3/s for 24 hours. How much volume changes?