Draining

Draining is the process of removing liquid from a substance, space, or system. It can occur naturally via gravity or be facilitated by devices and systems. The term also covers related processes in which a fluid is redirected or collected for disposal or reuse. In everyday language, draining describes both the action of removing water from soil or a container and the result, a drier condition.

In hydrology and civil engineering, drainage refers to the management of water in landscapes and built environments. Drainage networks include ditches, tile drains, sewers, and culverts that carry surface runoff and groundwater away from urban areas or agricultural fields. Proper drainage reduces flooding, supports crop production, and protects foundations and roads. Drainage density and pattern influence watershed behavior and soil moisture regimes.

In agriculture and soil science, drainage aims to prevent waterlogging and promote aeration. Surface drainage uses channels and furrows to remove water from the surface, while subsurface drainage uses perforated pipes or tiles to lower the water table. Maintenance includes cleaning outlets, repairing leaks, and ensuring outlets connect to appropriate disposal points.

In medicine and surgery, drainage involves the removal of fluids accumulated in tissues or cavities. Drains may be passive, such as soft flexible tubes that allow fluid to escape by gravity, or active, using pumps to apply suction. They help prevent infection, promote healing, and monitor exudate. Risks include irritation, blockage, and infection, so clinicians assess necessity and duration.

In electronics and engineering, the term drain appears as a component terminal in field-effect transistors, where current flows from drain to source under an applied voltage. The concept of drainage can also describe fluid removal practices in various industrial contexts.