P1A 06Glossary of Key Terms

Urbanization

• The process of increasing agricultural production in rural areas.

• The expansion of cities into rural regions, including activities like infrastructure development.

• The decline of population in urban areas due to migration.

• The establishment of wildlife reserves in urban settings.

Storm Water Sewers

• Large underground pipes designed to quickly move water away from settled areas to a nearby river.

• Small surface drains that collect rainwater and direct it to local ponds.

• Open ditches that allow stormwater to flow freely into the ocean.

• Pipes that filter and purify stormwater before it enters the drainage system.

Bull's eye effect

• The phenomenon where development expands outwards from urban centers, often into flood-prone areas.

• A method used in archery to measure accuracy.

• A visual illusion that causes concentric circles to appear distorted.

• A marketing strategy targeting specific demographics.

Lag Time

• The time between the peak rainfall intensity and the peak river discharge.

• The duration it takes for water to evaporate from a surface.

• The interval between two consecutive rainfall events.

• The time taken for a river to reach its maximum depth after a storm.

Surface Runoff

• Water that flows over the surface of the land during and after a rainfall event.

• Water that seeps into the ground during a rainfall event.

• Water that evaporates from the surface of the land after a rainfall event.

• Water that is stored in lakes and rivers during a rainfall event.

Floodplain

• An area of low-lying ground adjacent to a river, formed mainly of river sediments and subject to flooding.

• A high elevation area that is rarely affected by water.

• A region characterized by dry, arid conditions and minimal vegetation.

• A flat area that is always submerged under water.

Hydrograph

• A graph showing the rate of flow (discharge) versus time at a specific point on a river.

• A chart depicting the rainfall over a specific period.

• A diagram illustrating the water cycle stages.

• A map showing the geographical features of a river basin.

River Straightening

• A method of channelization that involves making a meandering river channel more direct.

• A technique used to increase the depth of a river for navigation.

• A process of creating artificial lakes by damming rivers.

• A method to enhance the natural meandering of rivers.

Falling Limb

• The portion of a hydrograph that shows the increase in river discharge after the peak discharge.

• The portion of a hydrograph that shows the decrease in river discharge after the peak discharge.

• The section of a river where water flows at a constant rate.

• The part of a hydrograph that represents the total rainfall over a period.

Encroachment on the River Channel

• The building of structures that reduce the original width of a river channel.

• The process of widening a river to increase water flow.

• The natural erosion of riverbanks over time.

• The construction of dams to control water levels.