Presentation on theme: "Running Water and Groundwater"— Presentation transcript:
1Running Water and Groundwater Oceans – 97 %Glaciers/ice – 2 %Freshwater - < 1 %Water cycle = the continuous circulation of earth’s water supplyIt is powered by the sun
2Evaporation = liquid to gas Condensation = gas to liquid (forms clouds)Precipitation = water (s,l ) returns to earthInfiltration = water that soaks into groundRunoff = water that flows across the groundTranspiration = water that plants release into the atmosphere (gas to liquid)
3Earth’s water cycle is balanced…if it wasn’t balanced, the earth would tip over and fall out of orbit and crash into the sun.Balanced = earth’s annual precipitation = the amount that evaporatesLocal imbalances do exist like droughts and floods.
4Stream FlowVelocity is the distance that water travels in a period of time. (some slow some fast)Highest velocities in the center of channelVelocity fastest on the outside bank/bend when a steam bends/curvesThe ability of a stream to erode & transport materials depends largely on its velocity
55 Stream Velocity Factors Gradient = slope (how steep or flat)Shape = crooked vs straightSize = wide vs narrow & deep vs shallowRoughness = smooth vs roughDischarge = the volume of water flowing past a certain point per unit of time (m3/s)
6Stream Profile Changes Profile - a cross-sectional stream viewGradient and roughness decrease as you go downstreamDischarge, velocity, depth, and width increases as you move downstreamThe ability of a stream to erode increases as the discharge increases.
7Stream Terms Tributary – anything that empties into another stream Base level – the lowest point to which a stream can erode its channelMeander – bends/curves in a river/streamOxbow lake – a meander that gets cut off from the main stream and form a small lake.
8Stream ErosionThe ability of stream to carry a load is dependent upon 2 factors:Competence - the largest particles the stream is transportingCapacity – the maximum load it can carrySteams generally erode “V” shaped valleys & channels in three waysAbrasionGrindingDissolving soluble materials
9Stream DepositionAs the stream slows down material/alluvium begins to settle outLarger materials settle out firstDelta – a triangular accumulation of sediment formed where a stream enters a lake/oceanLevee – accumulation of sediment along the river banksRivers carve
103 Stages of Stream Development 1 Young – fast, straight, narrow, rapids2 Mature – slower, meanders, wider3 Old – slowest, meanders/oxbows, widest
11Flooding Flood plain – flat areas along rivers that occasionally flood Flood contribution factors:PavingExcess precipitationMethods of controlDams and leveesLimiting development
12Drainage basin - the land area that contributes water to a stream Divide – imaginary line that separates one drainage basin of one stream from anotherDrainage patternsDendriticRadialBraidedTrellis/rectangular
13GroundwaterZone of saturation – area below ground where all the pore spaces are completely filled with waterZone of aeration – all the pore spaces are not completely filled with waterWater table – the line that divides the two
14Groundwater – It’s Underground Porosity – the percentage of the total volume of rock (or sediment) that consists of pore spacesPermeability – how well water moves through the rock/sedimentWell rounded and well sorted grains = high porosityAquifer – rock layers or sediment that allow groundwater to flow freely (sandstone)Aquitard – does not allow groundwater freely to flow freely (shale)
15Hot springs – water is heated from magma just below the surface Springs – form whenever the water table intersects the surface of the groundHot springs – water is heated from magma just below the surfaceGeysers – intermittent hot spring/fountain that periodically erupts (Old Faithful)Wells – a hole bored into the zone of saturationA pump is neededCone of depressionArtesian wells – groundwater rises on its own under pressure and no pump is neededRead pages 175/176 (env probs)
16Caverns A naturally formed underground chamber Usually forms in limestone from carbonic acid dissolving the rockTravertine – Calcium carbonate depositsStalactites, stalagmites, soda straws, curtains/ribbons, flowstone, etcKarst topography – limestone areas with many caves and sinkholes (collapsed caves)