waterretention

Water retention refers to the capacity of a system to hold water for a period of time. It is a concept used across soil science, biology, hydrology, and medicine to describe how water is stored, conserved, or accumulated.

In soils, water retention describes how much water remains in the soil after drainage. It depends on texture, structure, porosity, and organic matter. Key terms include field capacity (water retained after excess drainage) and wilting point (water content at which plants cannot recover). Available water capacity is the range between these two, and soil moisture characteristics curves relate water content to matric potential. Retention influences irrigation needs, drainage design, and drought resilience.

In plants and agriculture, retention refers to water stored in soil and plant tissues that supports turgor and metabolism. Root systems and stomatal regulation determine how efficiently water is used, while practices such as mulching and organic matter enrichment aim to increase in-soil retention and reduce evaporation.

In hydrology and urban planning, landscape water retention describes the ability of surface and subsurface features to store rainwater, slow runoff, and promote groundwater recharge. Wetlands, retention basins, permeable pavements, and green spaces enhance retention and reduce flood peaks.

In medicine, water retention or edema denotes abnormal accumulation of fluid in tissues, often linked to heart, liver, kidney disease, pregnancy, or medications. Management targets underlying causes, electrolyte balance, and fluid intake.

Enhancing retention generally involves increasing soil organic matter, reducing compaction, and using practices that conserve moisture, while appropriate drainage prevents waterlogging. Retention is influenced by climate, land use, and management.