What we will cover. The Hydrologic Cycle. River systems. Floods. Groundwater. Caves and Karst Topography. Hot springs

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Gyles Manning
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1 Fresh Water

2 What we will cover The Hydrologic Cycle River systems Floods Groundwater Caves and Karst Topography Hot springs

3 On a piece of paper, put these reservoirs of water in to order from largest to smallest Oceans Lakes Rivers Glaciers and continental ice Atmospheric water Soil moisture Groundwater

4 Distribution of water in the hydrosphere Reservoir (%) Oceans Glaciers and other ice Ground water Lakes Freshwater Lakes Saline Lakes Soil moisture Atmosphere Rivers

5 Hydrologic Cycle Hydrologic cycle - the movement and interchange of water between the sea, air, and land Precipitation Rain or snow Evaporation Solar radiation provides energy Transpiration Evaporation from plants Runoff Water flowing over land surface Infiltration Water soaking into the ground

6 IG4e_15_01 The Hydrologic Cycle About 90% returns to the tropical oceans

7 River Systems A river or stream is any body of water that is flowing downhill in a well defined channel River systems consist of a main channel and all its tributaries

8 Path of desire or path of least resistance? Desire Path: A term in landscape architecture used to describe a path that isn t designed but rather is worn casually away by people finding the shortest distance between two points.

9 River terminology Headwaters - upper part of stream near its source in the mountains Mouth - place where a stream enters sea, lake or larger stream Channel - a long, narrow depression eroded by a stream into rock or sediment Stream banks - sides of channel Streambed - bottom of the channel Floodplain - flat valley floor composed of sediment deposited by the stream

10 Channel floodplain floodplain Headwaters River Mouth A river system

11 Dendritic = tree-like or root-like Dendritic rivers in the flat midwest

12 Drainage basin River Systems The area of land that is drained by a certain river drainage system All the water in that area eventually finds its way into one of the rivers in the system Drainage divide Boundaries that separate one drainage basin from another Continental Divide separates the streams that flow into the Pacific from those that flow into the Atlantic and Gulf of Mexico

13 Mississippi River Drainage Basin

14 Missouri River Drainage Basin

15 Yellowstone River Drainage Basin

16 Powder River Drainage Basin

17 Mississippi River Drainage Basin

19 The Colorado: an incised meandering stream

20 The Colorado: downcutting due to tectonic uplift

21 Entrenched or incised river in its floodplain: Virgin River

22 Floods

24 IG4e_15_20

25 IG4e_15_22b

27 A braided stream in its floodplain: Laramie River

28 Oxbow lakes in a floodplain

29 Riparian foliage in a floodplain

32 IG4e_15_22c

34 Urban flooding Paved areas and storm sewers increase runoff by inhibiting infiltration Rapid delivery of water to streams increases peak discharge and hastens occurrence of flood Flooding

35 Mississippi River flood: Iowa

36 Mississippi River flood: Iowa

37 Mississippi River flood: Iowa

38 IG4e_15_01 The Hydrologic Cycle Groundwater is a very important reservoir

39 Ground Water precipitation either runs off or infiltrates into the soil as runoff, it flows into streams as infiltration, it either returns to the air through evapotranspiration or seeps downward to become ground water

40 Ground Water Figure 15.3, p. 514

41 Ground Water the water table marks the top of the saturated zone of ground water It generally reflects the overlying surface Figure 15.4, p. 515

42 Porosity and Permeability Porosity - the percentage of rock or sediment that consists of voids or openings Measurement of a rock s ability to hold water Loose sand has ~30-50% porosity Compacted sandstone may have only 10-20% porosity Permeability - the capacity of a rock to transmit fluid through pores and fractures Interconnectedness of pore spaces Most sandstones and conglomerates are porous and permeable Granites, schists, unfractured limestones are impermeable unless fractured

43 Well sorted sandstone Fig. 16-1a, p. 499

44 A poorly sorted sandstone Fig. 16-1b, p. 499

45 Fig. 16-1d, p. 499

Ground Water an aquifer is a layer of rock or sediment that contains abundant, freely flowing ground water aquicludes are beds of clay and shale

47 Ground Water an aquifer is a layer of rock or sediment that contains abundant, freely flowing ground water aquicludes are beds of clay and shale which are relatively impermeable a perched water table is an accumulation of water suspended or perched above the main water table Figure 15.5, p. 515

48 Porosity and Permeability Good aquifers Good aquitards

50 Fig. 16-4b, p. 502

52 Artesian Wells IG4e_15_06

53 Springs and Streams Spring - a place where water flows naturally from rock or sediment onto the ground surface Gaining streams - receive water from the saturated zone Losing streams - lose water to the saturated zone Stream beds lie above the water table

54 f11-7_basic_dynamics_of.swf

57 Ground Water Movement Movement of ground water through pores and fractures is relatively slow Flow velocity depends upon: Slope of the water table Permeability of the rock or sediment

59 Problems of Ground Water Management wells drawdown the water table at a point, creating a cone of depression as many wells exploit an aquifer, their cones of depression merge to create a general lowering of the water table Figure 15.12, p. 519

60 Water resources in coastal areas: Salt water encroachment

61 Changes in the Everglades due to lowering of the water table

Ground Water Contamination Infiltrating water may bring contaminants down to the water table, including (but not limited to): Pesticides/herbicides Fertilizers Landfill pollutants Heavy metals

62 Ground Water Contamination Infiltrating water may bring contaminants down to the water table, including (but not limited to): Pesticides/herbicides Fertilizers Landfill pollutants Heavy metals Bacteria, viruses and parasites from sewage Industrial chemicals (PCBs, TCE) Acid mine drainage Radioactive waste Oil and gasoline Contaminated ground water can be extremely difficult and expensive to clean up

67 What water does to Limestone

72 IG4e_15_11

75 Groundwater Erosion Groundwater chemically weathers & erodes the bedrock through dissolution Subsurface dissolution forms: Caves Sinkholes Karst topography

76 Fig. 16-1c, p. 499

77 Caves, Sinkholes, and Karst Caves - naturally-formed underground chambers Acidic ground water dissolves limestone along joints and bedding planes Caves near the surface may collapse and produce sinkholes Rolling hills, disappearing streams, and sinkholes are common in areas with karst topography

78 Karst Topography Karst topography is found in areas that have carbonate, sulfate, or salt beds at or near the ground surface Characterized by: Solution valleys Disappearing streams Sinkholes

79 Karst Topography

80 Karst Topography

81 Sinkholes

82 Sinkholes

90 Thermal Springs & Geysers Geysers and hot springs require: Hot rock bodies to heat groundwater Fractures system to transmit water Groundwater Geysers such as Old Faithful are the result

91 Fig a, p. 521

92 Fig b, p. 521

93 Thermal Springs & Geysers Hot water contains thermal energy and dissolved ions Geothermal energy taps heat source, but Many mineral deposits are produced by hot water interacting with cooling igneous intrusions

Geysers - hot springs that periodically erupt hot water and steam

94 Hot Water Underground Hot springs - springs in which the water is warmer than human body temperature Ground water heated by nearby magma bodies Geysers - hot springs that periodically erupt hot water and steam Minerals often precipitate around geysers as hot water cools rapidly in the air

99 Geothermal Energy Geothermal energy is produced using natural steam or superheated water No CO 2 or acid rain are produced (clean energy source) Some toxic gases given off (e.g., sulfur compounds) Can be used directly to heat buildings Superheated water can be very corrosive to pipes and equipment

100

101

102

103 Domestic Water Use human society is heavily dependent on fresh surface water for irrigation, potable water supplies, and industrial consumption artificial dams can increase freshwater supplies and generate power, but may have environmental costs

6.1 Water. The Water Cycle

6.1 Water. The Water Cycle 6.1 Water The Water Cycle Water constantly moves among the oceans, the atmosphere, the solid Earth, and the biosphere. This unending circulation of Earth s water supply is the water cycle. The Water Cycle