Objectives Describe how surface water can move weathered materials. Section 9.1 Surface Water Movement Objectives Describe how surface water can move weathered materials. Explain how a stream carries its load. Describe how a floodplain develops. Running water is an agent of erosion, carrying sediments in streams and rivers and depositing them downstream.

Section 9.1 1. Runoff

What determines the amount of runoff? Section 9.1 What determines the amount of runoff? 1. Soil composition Pore spaces: The particle size that makes up a soil helps determine the pore space of the soil. Porosity Activity Large grain size Fine grain size Mixed grain size

If precipitation exceeds infiltration, the water will become runoff. Section 9.1 What determines the amount of runoff? 2. Rate of precipitation If precipitation exceeds infiltration, the water will become runoff.

Vegetation slows runoff Section 9.1 What determines the amount of runoff? 3. Vegetation Vegetation slows runoff

The steeper the slope, the faster the water flows. Section 9.1 Surface Water Movement Runoff Activity 4. Slope Water from precipitation falling on slopes flows to areas of lower elevation. The steeper the slope, the faster the water flows.

Section 9.1 Surface Water Movement Stream Systems Some surface water flows in thin sheets and eventually collects in small channels, which are the physical areas where streams flow.

Stream Systems Tributaries Section 9.1 Surface Water Movement Stream Systems Tributaries Rivers that flow into other streams are called tributaries.

Stream Systems Watersheds and divides Section 9.1 Surface Water Movement Stream Systems Watersheds and divides All of the land area whose water drains into a stream system is called the system’s watershed. A divide is a high land area that separates one watershed from another.

The watershed of the Mississippi River Section 9.1 Surface Water Movement The watershed of the Mississippi River

Section 9.1 Surface Water Movement Stream Load The material that a stream carries is known as stream load. Stream load is carried in three ways.

Section 9.1 Surface Water Movement 1. Suspension all particles are held up by the turbulence of a stream’s moving water.

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Section 9.1 Surface Water Movement 2. Bed load sand, pebbles, and cobbles that can be rolled or pushed along the bed of the stream.

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Section 9.1 Stream Load Activity Surface Water Movement 3. Solution When water runs through or over rocks with soluble minerals, it dissolves small amounts of the minerals and carries them away in the solution.

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Stream Carrying Capacity Section 9.1 Surface Water Movement Stream Carrying Capacity The ability of a stream to transport material, referred to as its carrying capacity, Depends on both the velocity and the amount of water moving in the stream.

Section 9.1 Surface Water Movement Floods A flood occurs when water spills over the sides of a stream’s banks onto the adjacent land.

Flood plains Surface Water Movement Section 9.1 Surface Water Movement Flood plains The area that extends out from a stream’s bank and is covered by excess water during times of flooding is known as the stream’s floodplain

Section 9.2 Stream Development Objectives Describe some of the physical features of stream development. Describe the relationship between meanders and stream flow. Explain the process of rejuvenation in the stream development. Streams erode paths through sediment and rock, forming V-shaped stream valleys.

Section 9.2 Stream Development Supply of Water The region where water first accumulates to supply a stream is called the headwaters. Stream channels

Section 9.2 Stream Development Stream channels Moving water carves a narrow pathway into the sediment or rock called the stream channel.

Formation of Stream Valleys Section 9.2 Stream Development Formation of Stream Valleys A bend or curve in a stream channel caused by moving water is called a meander. Meanders

Meanders - Movie Clip Outside of meander Section 9.2 Stream Development Meanders - Movie Clip Outside of meander Water moving along the outside of a meander curve experiences the speed with the meander and erodes the side of the streambed. Inside of meander Along the inside of a meander, the water moves more slowly and deposition is dominant.

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Deposition of Sediment Section 9.2 Stream Development Deposition of Sediment When streams lose velocity, they lose some of the energy needed to transport sediment, and deposition of sediment occurs.

composed mostly of sand and gravel. Section 9.2 Stream Development 1. Alluvial fans fan-shaped, sloping depositional features that form when water flows down steep slopes onto flat plains. composed mostly of sand and gravel.

consist of layers of silt and clay particles. Section 9.2 Stream Development 2. Deltas triangular deposit that forms where a stream enters a large body of water consist of layers of silt and clay particles. Nile delta

Complete the diagram on page 43 Complete the front side of the worksheet using your notes and textbook “Features of a Meandering Stream”