Rivers How Do Rivers Change the Landscape

1. Erosion-Rivers wear away the rock 2. Transportation-Rocks are moved from one place to another in a river. The material moved in a river is called the river load 3. Deposition-Rivers drop the material in new places Erosion

 Hydraulic Action: The sheer force of the running water over the rock wears it down  Abrasion: The rocks in the river load hit off the river bed and sides causing it to break down.  Solution: Rocks are dissolved by the water (limestone)  Attrition: The river load hits off itself wearing it down Transportation Deposition

Rivers drop the load when:  They lose speed  Less water in the river  They flow into the sea or a lake  The land begins to get flat River Valley Youthful Stage

 Also called Upper course/valley

 The steepest part of a river profile.

 How do you think a river would move and look at this stage? Mature Stage

 Also known as middle course/valley

 Slope begins to get a bit gentler

 Would a river be bigger at this stage?

 What about the river load? Old Age Stage

 Also known as the lower course/valley

 River travels over almost flat land

 Will the river have much energy?

 What will happen to the load? V-Shaped Valley

 Steep narrow floors  Formed by vertical erosion  Weathering and mass movement cause sides of valley to move downslope. (V- Shape)  Example: River Lee and River Liffey

V-Shaped Valley V-Shaped Valley Interlocking Spurs

 High areas of ground that jut out from each side of the valley  Looks like they “lock” together  River will flow around resistant rock (while it keeps eroding downwards)  Examples: River Liffey and River Barrow Interlocking Spurs Potholes

 Just like the potholes in the road!  Circular shaped hollows found on the riverbed.  The river load cuts down into the bed and wear away the rocks  This is the process of ______ Examples: River Liffey and River Bandon Potholes Waterfalls Waterfalls Waterfalls

 Created when there are layers of both hard and soft rock  Water erodes the softer rock quicker than the harder, more resistant rock.  Once the soft rock is gone, an overhang is created.  A plunge pool is created over time Example:Torc Waterfall, Killarney, Co. Kerry Meanders Meanders Meanders Meanders Meanders-Mature Stage

 Bends or curves found along the mature course  Volume of the river and the load increases  Outer Bend: Water flows more quickly. Erosion here.  Inner Bend: Water flows more slowly. Deposition here.  Meanders become more pronounced over time.  Example: River Shannon Ox-Bow Lake Ox-Bow Lake