2. Puddles and Soil Infiltration &

3. Seeps Downhill and Soaks into the Rocks

1. Upstream or tributaries of the river.

2. Surface runoff.

3. Water that seeps downhill through the soil.

4. Ground water forced into the river through the bedrock.

5. Storm drainage systems from towns.

B. Velocity in a straight river section.

1. & 3. Slow surface velocity, decreasing towards the river bank.

2. Fast surface velocity.

4. (striped area) Fastest area of river flow.

5. Decreasing velocity towards the river bed.

C. Velocity, erosion and sediment load on a river bend.

1. (striped area) Fastest area of the river is often found close to the river bank. Erosion is greatest on the outside of the river bend, and can undercut the bank. Large sediment is found on the bed as all small particles are carried downstream in the fast flowing part of the river.

2. Slow velocity due to large amounts of friction between the river and the river bed. Small particles (sand and clay) may be found as sediment on the bed as this part of the river is not moving quick enough to keep these particles in suspension.

1. Rain water runs off the buildings (such as schools), roads and school playgrounds. Then it is channelled into storm drains.

2. The water has little chance of seeping into the ground due to the impermeable surfaces in built up areas, such as concrete and tarmac. This is called surface runoff.

3. The rain water then flows through the storm drains straight to the river. The time taken for the rain water to reach the river is far less than in a 'natural' environment. This can cause the river to rise rapidly and flood.