What causes the water to move? 1) Gravity - Rivers flow because of gravity as they begin in high areas and wind there way down towards the sea. Runoff from the surronding hills add to the flow. 2) Tidal Changes -The moon causes tidal changes in the ocean and at the beach.  The tide can make the water rise and fall in bodies of water that flow into the ocean. 3) Some bodies of water don`t move e.g billabongs, dams and swamps.
	How can flow be interrupted or changed? Natural  - Flow can be interrupted by big trees that have fallen down and blocked the river.  - A flood may change the course of a river for a short time or for ever. Man Made  - Removal of dead trees and debris from the river can change the flow and can cause tubidity and fish may die.  - Irrrigation can remove so much water from a river that it may stop the flow. - Dams and weirs can stop the flow of a river.
What difference does it make if the flow is changed?  If flow is lessend there is less oxygen, more silt and sediment and the water temperature is raised. If flow is speed up water tempreture lowers and water becomes turbid and causes fish to die.  Water creatures live in certain environments because it suits them.  If a part of their environment is changed, like the flow, it can kill many living creatures.
	What does flow have to do with oxygen? Moving water is more oxygenated than stagnate water. Water that flows and tumbles over rocks, gathers oxygen, so moving streams and rivers can support more life.
By Rhys, Ben and Peter