1.3.1 Floods/Stores and flows in the drainage basin

• input- pecipitation
• Output- river, evaporation, transportation
• flow- infiltration, percolation, through flow, groundwater flow, surface store
• storage- interception, surface store, soil moisture, ground water
• though flow- water that flows downhill through soil
• overland flow- water flows over the surface, perhaps as rivers or just as run off
• interception- when rain water is stopped in its path e.g. trees/leaves
• infiltration- water soaking into the ground
• percolation- water moving slowly through rocks and soil to reach an underground aquifer
• through flow- water flowing directly from one place to another without being stored
• surface stores- temporary storage on land such as ponds, lakes, rivers, reservoirs etc.
• surface stores- temporary storage of water on land
• soil moisture- water held within the top layer of soil by capillary action
• groundwater store- water that has percolated downwards and been held in rock fractures and pores
• evaporation- water changing state from liquid to gas (vapor)
• Flooding is influenced by houses, large amounts of flooding, flat lands, steep slopes, tributaries, vegetation, dams
• A hydrograph shows how a river discharge changes in response to a precipitation event
• In a hydrograph the vertical axis measures precipitation in millimetres and discharge in cubic meters per second
• In a hydrograph the horizontal axis measures time usually in hours or days
• In a hydrograph the bars represents rainfall and the line graph represents discharge
• River discharge - Amount of water in a river
• Peak rainfall - the amount of water that falls during a storm event
• Lag time - The river does not hit peak discharge until the water flows down the valley into the river, the time that takes is called lag time