Rivers Vocabulary + Case Study

• How many people live near the Mekong River?

  65 million.
• How much percent of the people living near the Mekong River depend upon the rich natural resources?

  80% of 65 million
• What do the majority of people who live near the Mekong River do?

  Majority of them, Mekong River is a market place.
• Winding almost 3,000 miles from the _____ Plateau down to the ____ Sea, accounts for __% of global freshwater.

  Winding almost 3,000 miles from the Tibetan Plateau down to the South China Sea, accounts for 25% of global freshwater.
• The negative effects of flood regularly counteracts efforts for economic development and ???? for various locations throughout the Lower Mekong Basin.

  The negative effects of flood regularly counteracts efforts for economic development and poverty reduction for various locations throughout the Lower Mekong Basin.
• Average annual costs of floods in the LMB ranges from US$__-___million.

  Average annual costs of floods in the LMB ranges from US$60-70million.
• Cambodia and Vietnam accounts for approximately __ of the total annual flood damages.

  Cambodia and Vietnam accounts for approximately 2/3rds of the total annual flood damages.
• How many people were evacuated from the village during the Cambodia 2018 flood?

  616,000 people.
• What are the strategies in the Flood Management and Mitigation (FMM) strategies?

  River monitoring, river flood forecasting, early warning, etc. (Hard to soft engineering strategies after the hydroelectric collapse which was the cause of the Cambodia 2018 flood).
• Open system (STORES)


  The basin cycle is an open system: the main input is precipitation, which is regulated by various means of storage.
• Precipitation (INPUTS)


  The main characteristics that affect local hydrology are the amount of precipitation, seasonality, intensity, type (snow, rain etc.) Precipitation is any liquid or frozen water that forms in the atmosphere and falls back to earth.
• Interception (STORES)


  Refers to water stored by vegetation. Interception refers to precipitation that does not reach the soil, but is instead intercepted by the leaves, branches of plants and the forest floor.
• Surface storage (STORES)


  The water that remains temporarily stored on the surface will eventually either evaporate or infiltrate. (Puddles) Water that infiltrates into the soil increases the soil water content and may ultimately be evaporated back to the atmosphere directly, be taken up by plants, or move deeper into the soil.
• Soil infiltration (FLOWS)


  Water infiltrates the soil by moving through the surface. The process by which water soaks into the ground.
• Soil moisture storage (FLOWS & STORES)

  Soil moisture is the subsurface water in soil and subsurface layers above the water table. When it is saturated, it just sits there being stored. It also moves very slowly.
• Deep percolation (FLOWS)


  (Percolation - the process of a liquid moving slowly through a substance that has very small holes in it), the water percolates into the deeper layers of the soil.
• Groundwater (STORES AND FLOWS)

  Refers to subsurface water. The upper layer of the permanently saturated zone is known as the water table. The rock that soaked up the water, rock that stores water is called an aquifer. Groundwater moves slowly due to gravity.
• Overland flow (rivers) (FLOWS)


  Refers to the water moving over the surface. It is also called surface runoff. (Like a sponge, after surface storage) (Main cause of flooding due to the other effects: precipitation, interception, and surface storage)
• Channel storage (STORES & OUTPUTS)

  The river is stored in a lake, then moves slowly. On the surface of the lake, evaporation takes place, that goes back to precipitation.
• Evapotranspiration (OUTPUTS)


  Evapotranspiration includes water evaporation into the atmosphere from the soil surface, evaporation from the capillary fringe of the groundwater table, and evaporation from water bodies on land.
• Groundwater flow (FLOWS)


  The deeper movement of water through subsurface water.
• Confluence


  The point where a smaller river joins a larger river.
• Tributaries


  Smaller rivers that join the larger river.
• Watersheds


  Imaginary lines separating adjacent basins.
• Abrasion (or corrasion)


  The wearing away of the bed and bank by the load carried by a river.
• Attrition


  The wearing away of the load carried by a river, which creates smaller, rounder particles.
• Hydraulic action


  The force of air and water on the sides of rivers and in cracks.
• Solution (or corrosion)


  The removal of chemical ions, especially calcium, which causes rocks to dissolve.
• Suspension


  Small particles are held up by turbulent flow in the river.
• Saltation


  Heavier particles are bounced or bumped along the bed of the river.
• Traction


  The heaviest material is dragged or rolled along the bed of the river.
• Flotation


  Leaves and twigs are carried on the surface of the river.
• Deposition

  As a river slows down and it loses its energy, it creates:

  - Deltas

  - Levées

  - Slip-off slopes

  - Oxbow lakes

  - Braided channels

  - Floodplains