: Outline Chapter 18 • Definition • Basins and divides: Colorado • & Gradients Rivers and Streams

Hydrologic Cycle Streams

• A is a that is confined in a and moves downhill under the influence of gravity. • This definition includes all sizes of running water from a tiny trickle to the Amazon. • The total area drained by a given stream is its .

Colorado Rivers Colorado DrainageN. Platte Basins Drainage Basins and Divides S. Platte Steamboat Boulder • The line separating one drainage basin from another is a drainage divide. • The Continental Divide separates Pueblo drainage basins of rivers that flow to Arkansas

the Atlantic and Gulf of Mexico from Alamosa those flowing to the Pacific and Gulf Durango

of Cortez (Gulf of California). Colorado

RioGrande

1 Clicker Question Clicker Question

• Water falling on Boulder goes down which • Water falling on Boulder goes down which system? river system? – A. Colorado River to Gulf of California – A. Colorado River to Gulf of California – B. North Platte to Missouri River to Mississippi – B. North Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – C. South Platte to Missouri River to – C. South Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans Mississippi River to Gulf of Mexico at New Orleans – D. Arkansas River to Mississippi River to Gulf of – C. Arkansas River to Mississippi River to Gulf of Mexico at New Orleans Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – D. Rio Grande To Gulf of Mexico at Brownsville, TX TX

Clicker Question Clicker Question

• Water falling on Pueblo goes down which • Water falling on Pueblo goes down which river system? river system? – A. Colorado River to Gulf of California – A. Colorado River to Gulf of California – B. North Platte to Missouri River to Mississippi – B. North Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – C. South Platte to Missouri River to Mississippi – C. South Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – D. Arkansas River to Mississippi River to Gulf of – D. Arkansas River to Mississippi River to Mexico at New Orleans Gulf of Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – E. Rio Grande To Gulf of Mexico at Brownsville, TX TX

Clicker Question Clicker Question

• Water falling on Alamosa goes down which • Snow melting at Leadville goes down which river system? river system? – A. Colorado River to Gulf of California – A. Colorado River to Gulf of California – B. North Platte to Missouri River to Mississippi – B. North Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – C. South Platte to Missouri River to Mississippi – C. South Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – D. Arkansas River to Mississippi River to Gulf of – D. Arkansas River to Mississippi River to Gulf of Mexico at New Orleans Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – E. Rio Grande To Gulf of Mexico at Brownsville, TX TX

2 Clicker Question Clicker Question

• Snow melting at Leadville goes down which • Snow melting at Breckenridge goes down river system? which river system? – A. Colorado River to Gulf of California – A. Blue River to Colorado River to Gulf of California – B. North Platte to Missouri River to Mississippi – B. North Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – C. South Platte to Missouri River to Mississippi – C. South Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – D. Arkansas River to Mississippi River to – D. Arkansas River to Mississippi River to Gulf of Gulf of Mexico at New Orleans Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – E. Rio Grande To Gulf of Mexico at Brownsville, TX TX

Clicker Question Clicker Question

• Snow melting at Breckenridge goes down • Snow melting at Steamboat Springs goes which river system? down which river system? – A. Blue River to Colorado River to Gulf of – A. Blue River to Colorado River to Gulf of California California – B. North Platte to Missouri River to Mississippi – B. North Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – C. South Platte to Missouri River to Mississippi – C. Yampa River to Green River to Colorado River River to Gulf of Mexico at New Orleans to Gulf of California – D. Arkansas River to Mississippi River to Gulf of – D. Arkansas River to Mississippi River to Gulf of Mexico at New Orleans Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – E. Rio Grande To Gulf of Mexico at Brownsville, TX TX

Clicker Question Clicker Question

• Snow melting at Steamboat Springs goes • Water falling on Alamosa goes down which down which river system? river system? – A. Blue River to Colorado River to Gulf of – A. Colorado River to Gulf of California California – B. North Platte to Missouri River to Mississippi – B. North Platte to Missouri River to Mississippi River to Gulf of Mexico at New Orleans River to Gulf of Mexico at New Orleans – C. Yampa River to Green River to – C. South Platte to Missouri River to Mississippi Colorado River to Gulf of California River to Gulf of Mexico at New Orleans – D. Arkansas River to Mississippi River to Gulf of – D. Arkansas River to Mississippi River to Gulf of Mexico at New Orleans Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – E. Rio Grande To Gulf of Mexico at Brownsville, TX TX

3 Clicker Question Clicker Question

• Snow melting at Durango goes down which • Snow melting at Purgatory (Durango) goes river system? down which river system? – A. Blue River to Colorado River to Gulf of – A. Blue River to Colorado River to Gulf of California California – B. Animas River to San Juan River to Colorado – B. Animas River to San Juan River to River to Gulf of California Colorado River to Gulf of California – C. Yampa River to Green River to Colorado River – C. Yampa River to Green River to Colorado River to Gulf of California to Gulf of California – D. Arkansas River to Mississippi River to Gulf of – D. Arkansas River to Mississippi River to Gulf of Mexico at New Orleans Mexico at New Orleans – E. Rio Grande To Gulf of Mexico at Brownsville, – E. Rio Grande To Gulf of Mexico at Brownsville, TX TX

Colorado Drainage Basins Floods

Steamboat Boulder • Flash floods can occur in a matter of hours as a result of a single storm.

Pueblo • Flash floods are most likely in areas of high gradients.

Alamosa • Annual floods result from Durango snowmelt or annual rain patterns (monsoons).

Annual Floods Flash , Boulder, 1894

4 , Boulder, 2013 Gradient • Gradient is the drop per mile (km). • Boulder Creek drops from 8000ft at Nederland to 5600’ in Boulder and has a gradient of 160 ft/mi (~30 m/km). • The Colorado River through Grand has a gradient of about 10 ft/mi (~2 m/km) • The lower Mississippi has a gradient of less than 0.5 ft/mi (~0.1 m/km). • Gradients usually decrease downstream.

Gradient Decreases downstream Stream Velocity

• Velocity is controlled by both gradient and channel size. • Steep gradients cause high velocities • Constricted channels cause high velocities.

Discharge • Boulder Creek is typically 10-25 cfs, but may be 500 cfs or greater in May • Discharge is the total flow in ft3/s (cfs) and June. or m3/s. • The Colorado at Grand Junction is • 1 m3/s = ~35 ft3/s (cfs). typically 2000 cfs, but may exceed • In a section of stream with no 30,000 in May and June. , the discharge is constant • The lower Mississippi is typically while the velocity and channel size 250,000 cfs but exceeded 3 million may vary along the bed. cfs in 1993 flood.

5 Load Load • The load is the amount of material transported by a stream. – is the material in solution. – is the material in suspension. – is the material on the bed • load is the material bouncing along the bottom. • Traction load is the material dragged along the bottom.

Deposition and

• The amount of bed load and suspended load vary with velocity. – Where a stream widens and slows, it deposits material. – Where a stream narrows and quickens, it erodes material.

Deposition, Erosion, Bedrock Yellowstone and Profiles channels River • Actively eroding streams valleys have a charac- teristic V-shape (no flood plain).

• Actively depositing stream valleys have flat bottoms (flood plain).

6 V-shaped Valley Incised – meandering streams that were once “alluvial channels” near , but base level changed so they began to (Byers Canyon) downcut again…what happened here? – rise of the Colorado Plateau

San Juan River, UT

U-shaped Valley U-shaped/V-shaped Valley (Arlberg, Austria) (Val Feret, Suisse)

Bars • Bars are material deposited by Flood streams. Plain – A point is a bar on the side of a stream. (Yampa) – A channel bar is a bar in the middle of a stream – A braided stream has many channels bars. • The presence of bars indicates that the steam is depositing.

7 Point Bars, Banks, Flood Plain (Yampa) Meanders, and Oxbows depositional

Flood Plain (Rhône) depositional Flood Plain (Yampa)

Braided Stream Antecedent Stream

8 Antecedent Stream Victoria Falls (Zambesi) Green River

Mississippi Delta Stream Terms • Stream • Flash flood • Hydrologic Cycle • Annual flood • Drainage divide • Point bar • Drainage basin • Channel bar • Gradient • Cut • Discharge • • Load • Oxbow – Suspended • Braided stream – Dissolved • Antecedent – Bed stream • Saltation • Traction • Delta

Profile: Profile: a: V-shape a: V-shape b: U-shape b: U-shape c: Flat floor c: Flat floor d: braided d: braided

9 Profile: Profile: a: V-shape a: V-shape b: U-shape b: U-shape c: Flat floor c: Flat floor d: braided d: braided

Profile: Profile: a: V-shape a: V-shape b: U-shape b: U-shape c: Flat floor c: Flat floor d: braided d: braided

Colorado River Drainage Basin

10 Colorado River Compacts, Links 1922, 1948 • Colorado River Basin • Divides flow above and below – www.cbrfc.noaa.gov Lee’s Ferry (below Lake Powell) • Colorado River Data • Upper Basin (“50%”): – Colorado(52%), Wyoming(14%), –waterdata.usgs.gov/co/nwis/rt Utah(23%), New Mexico (11%) • Colorado Water Law • Lower Basin (50%) –http://www.waterinfo.org/colorado- – California, Arizona, Nevada water/colorado-water-rights • Upper Basin states have never used their allocation.

Water Law V-shape: No Flood Plain

• Land owners do not own the water. • Prior users have precedent. • You may not restrict flow to deprive prior users downstream.

Antecedent Stream: Green River

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