6.1 Running Water 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 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.

6.2 Stream Erosion Streams erode their channels by 3 main processes…abrasion, grinding, and by dissolving particles. Streams carry their materials (loads) in 3 ways Dissolved load – dissolved particles Suspended load - carried by fast water Bed load – along the bottom…saltation

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

6.3 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 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

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)