Physical Geography of the Black Canyon of Gunnison

National ParkBy Alexandria LeFebre

Physical Geography – Fall 2011

December 4, 2011

Contents

• Place of Place of InterestInterest

• Erosion by Erosion by StreamflowStreamflow

• Transportation Transportation

• Deposition Deposition

• Down Cutting Down Cutting

• Perennial Perennial StreamsStreams

A Place of Interest

• The Black Canyon is one of the newest national parks

• Its annual visitation yearly average to 170,000 visitors dating from the year 2000.

• It was determined a national park on October 21, 1999

• Displays beautiful views/ Wildlife

• Plentiful activities- Hiking, Water rafting, fishing, etc.

Erosion by StreamflowErosion by Streamflow

• The Black Canyon was uniquely formed by The Black Canyon was uniquely formed by erosion of streamflow. erosion of streamflow.

• Erosion processErosion process

– As a stream enhances in volume and As a stream enhances in volume and velocity, its ability to transport materials velocity, its ability to transport materials become highly dominate.become highly dominate.

Transportation

• Any form of down sloping water can Any form of down sloping water can carry/transport materials. carry/transport materials.

• In the process of naturally constructing a In the process of naturally constructing a land feature, in order to make progress, land feature, in order to make progress, anything in the way of the finished project anything in the way of the finished project must be casted out in which transportation is must be casted out in which transportation is of aid in carrying all unwanted materials of aid in carrying all unwanted materials downstream. downstream. – Black Canyon’s bed-load Black Canyon’s bed-load • Sand, gravel ,rock fragments, boulders, debris, etc. Sand, gravel ,rock fragments, boulders, debris, etc.

Deposition

• When a river experiences a decrease in When a river experiences a decrease in velocity or volume, the river discards its bed-velocity or volume, the river discards its bed-load. This is seen along various parts of the load. This is seen along various parts of the Gunnison river.Gunnison river.– Reduction in velocity occurs when:Reduction in velocity occurs when:• the land lays flatthe land lays flat

• river widens in width river widens in width

– Reduction in volume occurs when:Reduction in volume occurs when:• area experiences a dry seasonarea experiences a dry season

• river passes along absorbent land river passes along absorbent land

Down Cutting

• The Black Canyon is identified through the The Black Canyon is identified through the process of down cutting. process of down cutting.

• Down Cutting is the deepening of a valley Down Cutting is the deepening of a valley due to erosion. due to erosion. – Causes:Causes:• High volume/velocity of riverHigh volume/velocity of river

– Effects:Effects:• Deeper water channel Deeper water channel

• ““V” shape in canyon V” shape in canyon

• Steep wallsSteep walls

• Lowering of streambedLowering of streambed

Perennial Streams Perennial Streams

• Identifying the Gunnison River as a perennial Identifying the Gunnison River as a perennial stream. stream.

• It’s a permanent land feature that constantly It’s a permanent land feature that constantly flows year roundflows year round

• A key component in the survival of wildlife in A key component in the survival of wildlife in the areathe area

Imprint in Physical Geography

• The Black Canyon of Gunnison National Park The Black Canyon of Gunnison National Park is one iconic land feature that has been is one iconic land feature that has been noticed for its renowned fluvial erosion noticed for its renowned fluvial erosion effect that was formed through the effect that was formed through the millenniums. This will be an eternal millenniums. This will be an eternal topography that will be enjoyed and studied topography that will be enjoyed and studied for many more millenniums to come.for many more millenniums to come.