Due Tuesday, May 31 st at beginning of class Go to and enter 101 in left navbar search field. On G101 web page, download Problem Set #3, PDF file.  Discharge, stream velocity, wetted perimeter  Simple calculations  Need to understand units of calculations (e.g., m/sec or m 3 /sec) Problem Set 3

Hydrologic cycle Streams

V. Stream Transport A.Sediment Load 1.Dissolved Load All natural water carries ions in solution Source from groundwater Ions are commonly bicarbonate, Ca, Mg, Na Warm & wet environment  more dissolved load Cold & dry environment  less dissolved load Streams

V. Stream Transport A. Sediment Load 2. Suspended Load: most sediment, consisting of clay, silt, very fine sand Depends on: Stream velocity faster = more suspended load Particle shape, flatter = better suspended Particle densitylow density = better suspended Examples: Colorado is Red = red suspended load Yellow River in China = yellow silt Streams

V. Stream Transport A.Sediment Load 3. Bed Load Transported along the bottom a. Saltation—bouncing motion, jump or skip along b. Traction—rolling or sliding along

Streams

V. Stream Transport B. Capacity a. The maximum load of sediment that a stream can transport (volume/time) b. Related to discharge Streams

V. Stream Transport C. Competence a. The diameter (size) of the largest particle that a stream can transport b. Related to velocity (squared) Higher velocity = carry larger sediments Streams

VI. Deposition A. In-Channel deposits 1. Braided Streams = sand and gravel bars 2. Meandering Streams = point bars on inside of meander Streams Point bar deposits on inside of meander, Mississippi River

Streams

Point bar deposits under farmland

VI. Deposition A. In-Channel deposits 1. Braided Streams = sand and gravel bars 2. Meandering Streams = point bars on inside of meander Streams Sand and gravel bars in braided stream, Alaska

Streams Braided channel, Taklat River, Denali National Park, Alaska

VI. Deposition B. Floodplains Floods have high velocity  high sediment load Overflow their banks  lower velocity  drop sediment load Levees: ridges of sediment on either side of the stream Larger sediment forms the levees, the smaller sediment is deposited further out on the floodplain Streams

VI. Deposition B. Floodplains Floods have high velocity  high sediment load Overflow their banks  lower velocity  drop sediment load Levees: ridges of sediment on either side of the stream Larger sediment forms the levees, the smaller sediment is deposited further out on the floodplain Streams

VI. Deposition C. Deltas Stream flows into standing water (lake or ocean) Fan-shaped Nile and Mississippi River deltas Deltas do not form in some rivers – e.g., Columbia and Amazon rivers because oceans more vigorous Streams

VI. Deposition C. Deltas Stream flows into standing water (lake or ocean) Fan-shaped Nile and Mississippi River deltas Deltas do not form in some rivers – e.g., Columbia and Amazon rivers because oceans more vigorous Streams

Modern Mississippi River delta

VI. Deposition D. Alluvial Fans Form where stream valleys widen When narrow mountain streams reach flat plains Drop in gradient, Drop in velocity (wider--more open) Drop in carrying capacity Fan-shaped geometry

VI. Deposition D. Alluvial Fans Form where stream valleys widen When narrow mountain streams reach flat plains Drop in gradient, Drop in velocity (wider--more open) Drop in carrying capacity Fan-shaped geometry

1993 Mississippi Flood

Streams