Drainage is a term used in the field of hydraulic engineering and water management to refer to the process of evacuation or drainage of stormwater, wastewater or groundwater from a land, infrastructure or system, with the aim of avoiding flooding, flooding or structural damage.[1] Drainage can be carried out naturally or through artificial systems, such as drainage networks, canals, sewers or hydraulic pumps").

There are several types of drainage depending on their purpose or method:[2]​.

Drainage is essential in the design of roads, railways, airports, agricultural areas and urban centers. A poor drainage system can cause the appearance of sinkholes, erosion, structural collapse") or recurrent flooding.[2]​.

In Spain, urban planning and flood protection plans usually incorporate hydrological studies that include drainage analysis as a key element in territorial planning. A notable example is the Comprehensive Flood Plan of the Valencian Community, which contemplates drainage as one of the pillars in improving urban resilience.[3]​.