Urban Drainage Engineering

These flashcards cover key terminology and concepts related to urban drainage engineering.

Drainage

The removal of excess water from a given place, either naturally or artificially.

Urban Drainage

The removal of excess surface and sub-surface water specifically from urban areas.

Wastewater

Water that has been used to support life or industry, potentially causing pollution if not drained properly.

Stormwater

Rainwater or water from precipitation that falls on a built-up area and must be managed to prevent flooding.

Surface Drains

Drains that remove water from the ground surface before it infiltrates into the soil.

Subsurface Drains

Drains designed to facilitate the movement of water through soil, preventing water table rise.

Combined Sewer System

A sewer system that carries both domestic sewage and stormwater runoff in the same pipe.

Separate Sewer System

A sewer system that transports wastewater and stormwater in separate pipes or channels.

Partially Separate System

A drainage system that combines some stormwater with sewage while separately collecting other stormwater.

Runoff Coefficient

A measure of the fraction of rainfall that becomes runoff for a specific area, influenced by surface characteristics.

Time of Concentration

The time it takes for water to travel from the furthest point of a watershed to the outlet.

Manning’s Formula

A formula used to calculate the velocity of water flow in open channels based on channel characteristics.

Peak Flow

The maximum rate of flow of stormwater that a drainage system can accommodate during a rainfall event.

Hydrologic Cycle

The continuous movement of water within the Earth and atmosphere, involving processes such as evaporation, condensation, and runoff.

Evapo-transpiration

The sum of evaporation and plant transpiration from the Earth's surface to the atmosphere.

Blockages

Full or partial restrictions within a sewer that impede water flow, often due to construction defects or solid accumulation.

Sedimentation

The process whereby solid particles settle out of the water column and accumulate at the bottom of the sewer.

Grease/Scale

Accumulation of solidified grease in sewer systems, often reducing hydraulic capacity.