Water Resources, the Water Cycle, and Flooding in China

Comprehensive vocabulary flashcards covering the hydrological cycle, water resources calculation, major Chinese rivers, regional climatic differences, causes and impacts of flooding, and engineering and non-engineering flood mitigation measures in China.

Evaporation

The hydrological process where water in seas, rivers, lakes, and soil heats up, changes state, and becomes water vapour.

Condensation

The hydrological process where rising water vapour cools, turns into water droplets, and groups together to form clouds.

Precipitation

The falling of water from clouds to the ground as rain or snow when the air can no longer hold the accumulated moisture.

Transpiration

The biological process in the water cycle where the leaves of plants release water into the air as water vapour.

Infiltration

The process by which water on the ground surface seeps into the soil and rock layers to become groundwater.

Overland Flow

The movement of rainwater or meltwater flowing directly down slopes across the ground surface.

Per Capita Water Resources

A measurement calculated by dividing the total water resources of a place by its population: $\frac{\text{Total water resources of a place}}{\text{population}}$, expressed in $\text{m}^3$.

Major Rivers of China (Numbered 1 to 7)

1: Songhua Jiang, 2: Liao He, 3: Hai He, 4: Huang He, 5: Huai He, 6: Chang Jiang, 7: Zhu Jiang.

Wet and Dry Regions in China

Climatic moisture zones defined by annual precipitation: Humid region (over $800\,\text{mm}$), Semi-humid region ($400\,\text{mm}$ to $800\,\text{mm}$), Semi-arid region ($200\,\text{mm}$ to $400\,\text{mm}$), and Arid region ($0\,\text{mm}$ to $200\,\text{mm}$).

Monsoons

Winds that reverse direction seasonally, formed primarily by the differential heating of land and sea.

Monsoon Region of China

The eastern and southern parts of China where summer onshore monsoons blow moist air from sea to land, producing higher rainfall and a humid climate.

Non-monsoon Region of China

The northwestern part of China that is not reached by summer monsoons, resulting in lower rainfall and a dry climate.

Relief Barrier in Western China

High mountain chains in western China that block moist onshore winds blowing from the Indian Ocean, leaving the air dry by the time it reaches northwestern China.

Flooding

A condition that occurs when a river channel cannot hold all the flow and excess water overflows the river banks.

River Holding Capacity

The volume of flow a river channel can accommodate without overflowing; it decreases when riverbeds become shallow due to silting.

Risk of Flooding in China

A distribution where flood risk is concentrated in eastern and southern China, particularly along the lower courses and floodplains of the Huang He, Chang Jiang, and Zhu Jiang.

Storm Surge

An abnormal rise of coastal water generated by typhoons that leads to extensive flooding in coastal areas.

Low-lying Relief (Cause of Flooding)

The flat, gentle topography characterizing the lower river courses in eastern China, which slows river flow and promotes sediment deposition, making riverbeds shallower.

Deforestation (Cause of Flooding)

The clearance of large forest areas for materials, fuel, and land, which reduces protective vegetation, intensifies soil erosion, and silts up riverbeds to diminish channel capacity.

Reclamation of Lakes

The draining and filling of natural lakes for agriculture and urban development, destroying their capacity to store floodwater and regulate river discharge.

Impermeable Urban Surfaces

Paved concrete and asphalt ground surfaces in cities that block water infiltration into the soil, drastically increasing surface runoff during rainstorms.

Impacts of Flooding in China

1: Injury and loss of life; 2: Diseases caused by drinking polluted water; 3: Disruption of utility supplies such as gas and electricity; 4: Disruption of transport services; 5: Structural damage to buildings, roads, and bridges; 6: Flooding of agricultural fields causing crop failure.

Dam (Flood Prevention)

An engineered barrier constructed across a river to regulate discharge and prevent excessive water from surging downstream.

Reservoir

An artificial lake or storage facility built behind a dam to store surplus rainwater during periods of high flow.

Dyke

An earthen wall or embankment constructed along river banks to heighten the channel walls and prevent floodwaters from spilling onto adjacent land.

Dredging

The mechanical excavation of accumulated sediment and mud from riverbeds to restore channel depth and maintain holding capacity.

Returning Farmland to Forest Programme

A government afforestation initiative implemented along the Chang Jiang to convert agricultural land back into forest cover to reduce soil erosion.

Returning Farmland to Lake Programme

An environmental restoration programme carried out to ban illegal reclamation and restore the water storage capacity of natural lakes.

Land Use Zoning (Flood Management)

A planning strategy that regulates building density and the type of development along river corridors in proportion to the localized risk of flooding.

Flood Warning System

A technological monitoring network that tracks rainfall levels and river stages to issue early alerts so authorities and citizens can take precautionary measures.

Remedial Flood Measures

Post-disaster emergency responses divided into immediate rescue (dispatching teams and supplying food and water) and clean-up works (draining floodwater, clearing streets, and repairing damaged infrastructure).