1 Hydrologic Cycle. Chin - chapter 1. Dr. Luis E. Lesser

Transcription

1 1 Hydrologic Cycle Chin - chapter 1 Dr. Luis E. Lesser All Tables and Figures (except where noted) were kindly provided by Pearson, from the textbook by David A. Chin, Water Resources Engineering, 3 rd edition.

2 Hydrologic cycle

3 Hydrologic cycle GREEKS influenced by their visual observations of karst Theorized the existence of one or various caverns in the interior of the earth Sea Limitless? Recharge? Springs and rivers Caverns

4 Hydrologic cycle Thales of Miletus (650 BC) Springs and Rivers feed by oceans. The water would rise by rock pressure Plato (400 BC) Tartarus, water from the sea into the mountains by effect of tides, waves and pressures of rocks Aristotle (350 BC) Book Meteorlogica. Distillation through pores from the center of the earth (removes salt) China (2000 BC) Open wells (norias). Wells drilled to m deep. Only until the XIX century these depth were equaled Egypt and Persia More than 2500 years ago created filtrant galleries called kanats

5 Hydrologic cycle Bernard Palissy ( ) First one to suggest that the origin of spring water may be from precipitation at the moment, scientists did not pay much attention Pierre Perrault In 1674 published "De I'origine des Fontaines, with data from flow measurements from the Seine river as well as precipitation data from the upper Seine basin. Mariotte In 1685 confirmed the results by Perreault in "Traité du mouvement des Eaux et des autres Corps fluides" Edmund Halley Evaporation studies (1687 and 1691)

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7 Estimated World Water Quantities The largest source of fresh water is contained in the polar ice caps The largest source of fresh water available to humans is groundwater

8 Estimated World Water Quantities From: Fetter, 1992

9 Estimated World Water Quantities From: Fitts, 2002

10 Key components of the hydrologic cycle Storage: Water storage in oceans Water storage in ice and snow Water storage as groundwater in aquifer Water storage as freshwater lakes, ponds, and reservoirs Water on the earth's surface: Snowmelt Surface runoff Streamflow Springs Water in the atmosphere: Condensation Precipitation Evaporation Transpiration Water below the earth's surface: Infiltration Soil moisture Groundwater recharge

11 Meteorological Budget The volume of water at any point in a hydrologic system can be calculated as the difference between the inflow and outflow of the system resulting in a change in storage. I O = S I = Inflow O = Outflow S = Change instorage

12 Atmospheric Water Rain gauges are the traditional method for measuring precipitation

13 Atmospheric Water Transpiration is the process by which the soil moisture taken up by a plant root system is eventually evaporated Evapotranspiration: the combined effect of evaporation and transpiration - generally taken together as evapotranspiration From: COMET is a registered trademark of UCAR , University Corporation for Atmospheric Research. All Rights Reserved.

14 Surface Water Infiltration is defined as the downward movement of water through soil The rate of infiltration is directly influenced by the physical characteristics of the soil, soil cover, moisture content of the soil, soil temperature, precipitation rate, and rainfall intensity When precipitation rate > infiltration capacity, surface runoff will occur (01 Soil Texture - ANIMATION)

15 Surface Water Runoff is that portion of rainfall that does not infiltrate into the soil As the soil becomes saturated, less infiltration will take place. A graph of streamflow is called a hydrograph. The shape of the hydrograph is influenced by the precipitation and basin characteristics. From: COMET is a registered trademark of UCAR , University Corporation for Atmospheric Research. All Rights Reserved.

16 Groundwater Groundwater is an extremely important source of water. It is not subject to the same evaporation rates as surface water (rivers or lakes) Aquifers are composed of materials in the subsurface (soil, void space and water) From: COMET is a registered trademark of UCAR , University Corporation for Atmospheric Research. All Rights Reserved.

17 Groundwater In unconfined aquifers, the groundwater is in contact with the atmosphere through the pores of the overlaying soil. Aquitard From: COMET is a registered trademark of UCAR , University Corporation for Atmospheric Research. All Rights Reserved.

18 Groundwater In confined aquifers there is an aquitard on top (layer with very low permeability) Aquitard From: COMET is a registered trademark of UCAR , University Corporation for Atmospheric Research. All Rights Reserved.

19 MetEd Online - 2 1) Do: Runoff Processes" (approx. 2.5 hrs)