GEOG 1113 NOTES pt 11 - GEOG 1113 NOTES pt 11 HYDROLOGIC...

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GEOG 1113 NOTES pt 11 HYDROLOGIC SYSTEMS ** WATER (H2O) * originally formed within the Earth & brought to the surface by outgassing, which is the release of trapped gasses from rocks, forced out through cracks, fissures, & volcanoes from within the Earth * collected on the surface after the Earth cooled about 3.8 BYBP * reached present amount, about 1.36 billion km3, about 2 BYBP * covers approximately 71% of the Earth's surface Other than gravity, water is the major agent of geomorphic change on the earth’s surface * Distribution 97.22 % is in the oceans, 2.78 % is freshwater. * of this freshwater: * of this 77.78% surface water: 99.357% in ice & glaciers, .33% in freshwater lakes & ponds, .003% is in rivers & streams, .28% is in saline lakes, and .03% is in the atmosphere * Properties of water: * occurs in all 3 states (phases) of matter (solid, liquid, gas) at the T°s found on Earth * undergoes phase changes (melting, freezing, evaporation, condensation, sublimation, & deposition) * to change phase energy is either added or released ** HYDROLOGIC CYCLE * the flow of water through the environment * includes all phases, all 4 of Earth's spheres, & various pathways * Basic cycle: * evapotranspiration (evaporation + transpiration by plants): water is converted from the liquid form to the gaseous form & rises into the atmosphere
* condensation: water vapor is converted back to the liquid form (cloud and raindrops) * precipitation: water returns to surface as rain, snow, etc. * after precipitation, water either soaks into the surface, infiltration, or is run-offs (overland flow) into streams, lakes, & other water bodies * Water Balance: the amount of water in an area based on input (precipitation) minus output (usage, evaporation, storage) * hydrologic cycle, if balanced, provides an adequate water supply for plants, animals, and various processes * water is a major factor in weathering processes above & below the surface, & thus landform development (Increased water == increased weathering) * How it affects weathering: Infiltration vs runoff subsurface weathering fluvial landscapes regolith formation degradation karst formation aggradation overland flow FLUVIAL SYSTEMS * What is a fluvial system? Primarily this refers to “running water” * rills, brooks, creeks, streams, rivers, & other water moving in a channel or watercourse * may be a permanent watercourse or temporary (intermittent) * in arid regions intermittent channels are also known as arroyos, wadis, dry gulches, washes, etc. Running water causes erosion and transport of weather material. * in some cases standing water such as lakes or ponds are included but carryout
more weathering than transport, and are more likely to be areas of aggradation * How do they induce change on the landscape? ** 2 main processes by which is induced: Degradation: wear down Earth’s materials and surface: erosion. Aggradation: the build-up of Earth’s surface: deposition.

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