Lecture 12 Streams and Floods

Lecture Outline IThe Hydrologic Cycle IIDefinitions IIIDrainage A)Runoff i.Channel Flow ii.Sheet Flow B)Drainage Basins i.Mississippi River Drainage Basin ii.Chesapeake Bay Drainage Basin C)Stream Order D)Drainage Patterns i.Dendritic ii.Radial iii.Rectangular iv.Trellis E)Stream Valley Development i.Base Level Lecture 12 i

Lecture Outline IIIDrainage E)Stream Valley Development ii.The Graded Stream iii.Lateral Erosion iv.Headward Erosion IVStream Function A)Controls on Stream Function i.Velocity ii.Channel Properties iii.Gradient iv.Discharge B)Erosion C)Transportation D)Deposition i.Bars ii.Braided Streams iii.Meandering Streams and Point Bars Lecture 12 ii

Lecture Outline Lecture 12 iii IVStream Function D)Deposition iv.Flood Plains v.Deltas vi.Alluvial Fans VOther Fluvial Morphologies A)Stream Terraces B)Incised Meanders C)Superposed Streams

The Hydrologic Cycle Lecture 12 I

Definitions Lecture 12 II stream - a body of water found on Earth's surface and confined to a narrow topographic depression, down which it flows and transports rock particles, sediment, and dissolved particles. Rivers, creeks, brooks, and runs are all streams.

Runoff Lecture 12 III.A Channel Flow Sheet Flow

Runoff Overland (Sheet) Flow Lecture 12 III.A

Drainage Basin Lecture 12 III.B drainage basin - the total land surface drained by a system of streams leading to the same outflow. drainage system - the streams, tributaries, and other bodies of water by which a region is drained. drainage divide - the boundary between adjacent drainage basins.

Drainage Basin Mississippi River and Chesapeake Bay Lecture 12 III.B.i

Stream Order Lecture 12 III.C stream order - a classification of relative position of streams in a channel network, assigning each link an integer order number determined by the pattern of confluences in the tributary network headward of the given link.

Stream System Components Lecture 12 III.C

Drainage Patterns Lecture 12 III.D Dendritic Radial Rectangular Trellis Deranged

Drainage Patterns Dendritic Lecture 12 III.D.1

Drainage Patterns Radial Lecture 12 III.D.2

Drainage Patterns Rectangular Lecture 12 III.D.3

Drainage Patterns Trellis Lecture 12 III.D.4

Drainage Patterns Deranged Lecture 12 III.D.4

The Stream Valley Lecture 12 III.D.4

Stream Valley Development Evolution Lecture 12 III.E.iii

Stream Valley Development Stream Profile Lecture 12 III.E Base Level/Grade Lateral Erosion Headward Erosion

Stream Valley Development Base Level Lecture 12 III.E.i

Stream Valley Development The Graded Stream Lecture 12 III.E.ii graded stream - a stream maintaining an equilibrium between the processes of erosion and deposition, and therefore between aggradation and degradation.

Stream Valley Development Lateral Erosion Lecture 12 III.E.iii

Stream Valley Development Evolution – Headward Erosion Lecture 12 III.E.iii

Stream Functions Lecture 12 IV Erosion Transportation Deposition

Controls on Stream Function Lecture 12 IV.A Velocity Channel Properties Gradient Discharge

Controls on Stream Function Velocity Lecture 12 IV.A.i

Controls on Stream Function Channel Properties – Cross-Sectional Area Lecture 12 IV.A.ii.1

Controls on Stream Function Channel Properties – Longitudinal Organization Lecture 12 IV.A.ii Straight Channel Meandering Channel Braided Channel

Controls on Stream Function Straight Channel Lecture 12 IV.A.ii

Controls on Stream Function Meandering Channel Lecture 12 IV.A.ii

Controls on Stream Function Braided Channel Lecture 12 IV.A.ii

Controls on Stream Function Gradient Lecture 12 IV.A.iii

Controls on Stream Function Discharge Lecture 12 IV.A.iv discharge : volume of water flowing past a point in a given amount of time.

Erosion Lecture 12 IV.B

Sediment Transport Lecture 12 IV.C capacity: the total volume of sediments a stream can carry; a function of discharge competence:the maximum size of sediment the stream can carry Transport Modes 1 Suspended load 2 Bed load 3 Dissolved load

Depositional and Other Fluvial Landforms Lecture 12 IV.D Flood Plains Meandering Stream Point Bar Cutbank Oxbow Lakes Natural Levees Overbank Deposits Yazoo Tributary Backswamps Bars Braided Streams Deltas Alluvial Fans

Flood Plains Lecture 12 IV.D.iv

Meandering Streams and Point Bars Lecture 12 IV.D.iii

Meandering Streams and Point Bars Lecture 12 IV.D.iii

Meandering Streams Migration Lecture 12 IV.D.iii

Lecture 12 IV.D.iii Meandering Streams and Oxbow Lakes

Flood Plains Natural Levees Lecture 12 IV.D.iv Natural levees

Bars Lecture 12 IV.D.i

Braided Streams Lecture 12 IV.D.ii

Deltas Lecture 12 IV.D.v

Deltas Lecture 12 IV.D.v

Alluvial Fans Lecture 12 IV.D.vi Alluvial Fan (Death Valley, CA)

Other Fluvial Morphologies Lecture 12 V Stream Terraces Incised Meanders Superposed Streams

Stream Terraces Lecture 12 V.A

Incised Meanders Lecture 12 V.B

Superposed Streams Lecture 12 V.C