Running Water and Groundwater Oceans – 97 % Glaciers/ice – 2 % Freshwater - < 1 % Water cycle = the continuous circulation of earth’s water supply It is powered by the sun

Evaporation = liquid to gas Condensation = gas to liquid (forms clouds) Precipitation = water (s,l ) returns to earth Infiltration = water that soaks into ground Runoff = water that flows across the ground Transpiration = water that plants release into the atmosphere (gas to liquid)

Earth’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 evaporates Local imbalances do exist like droughts and floods.

Stream Flow Velocity is the distance that water travels in a period of time. (some slow some fast) Highest velocities in the center of channel Velocity fastest on the outside bank/bend when a steam bends/curves The ability of a stream to erode & transport materials depends largely on its velocity

5 Stream Velocity Factors Gradient = slope (how steep or flat) Shape = crooked vs straight Size = wide vs narrow & deep vs shallow Roughness = smooth vs rough Discharge = the volume of water flowing past a certain point per unit of time (m3/s)

Stream Profile Changes Profile - a cross-sectional stream view Gradient and roughness decrease as you go downstream Discharge, velocity, depth, and width increases as you move downstream The ability of a stream to erode increases as the discharge increases.

Stream Terms Tributary – anything that empties into another stream Base level – the lowest point to which a stream can erode its channel Meander – bends/curves in a river/stream Oxbow lake – a meander that gets cut off from the main stream and form a small lake.

Stream Erosion The ability of stream to carry a load is dependent upon 2 factors: Competence - the largest particles the stream is transporting Capacity – the maximum load it can carry Steams generally erode “V” shaped valleys & channels in three ways Abrasion Grinding Dissolving soluble materials

Stream Deposition As the stream slows down material/alluvium begins to settle out Larger materials settle out first Delta – a triangular accumulation of sediment formed where a stream enters a lake/ocean Levee – accumulation of sediment along the river banks Rivers carve

3 Stages of Stream Development 1 Young – fast, straight, narrow, rapids 2 Mature – slower, meanders, wider 3 Old – slowest, meanders/oxbows, widest

Flooding Flood plain – flat areas along rivers that occasionally flood Flood contribution factors: Paving Excess precipitation Methods of control Dams and levees Limiting development

Drainage basin - the land area that contributes water to a stream Divide – imaginary line that separates one drainage basin of one stream from another Drainage patterns Dendritic Radial Braided Trellis/rectangular

Groundwater Zone of saturation – area below ground where all the pore spaces are completely filled with water Zone of aeration – all the pore spaces are not completely filled with water Water table – the line that divides the two

Groundwater – It’s Underground Porosity – the percentage of the total volume of rock (or sediment) that consists of pore spaces Permeability – how well water moves through the rock/sediment Well rounded and well sorted grains = high porosity Aquifer – rock layers or sediment that allow groundwater to flow freely (sandstone) Aquitard – does not allow groundwater freely to flow freely (shale)

Hot springs – water is heated from magma just below the surface Springs – form whenever the water table intersects the surface of the ground Hot springs – water is heated from magma just below the surface Geysers – intermittent hot spring/fountain that periodically erupts (Old Faithful) Wells – a hole bored into the zone of saturation A pump is needed Cone of depression Artesian wells – groundwater rises on its own under pressure and no pump is needed Read pages 175/176 (env probs)

Caverns A naturally formed underground chamber Usually forms in limestone from carbonic acid dissolving the rock Travertine – Calcium carbonate deposits Stalactites, stalagmites, soda straws, curtains/ribbons, flowstone, etc Karst topography – limestone areas with many caves and sinkholes (collapsed caves)