A riparian zone, also known as a riparian area, is the interface between land and a river or stream. It is a transitional semiterrestrial/semiaquatic area regularly influenced by fresh water, usually extending from the edges of water bodies to the surrounding uplands. Riparian zones are important in ecology, environmental resource management, and civil engineering because of their role in soil conservation, their habitat biodiversity, and the influence they have on terrestrial and semiaquatic fauna as well as aquatic ecosystems.

Riparian zones provide many important functions and benefits, including:

• Soil conservation: Riparian zones are important natural biofilters, protecting aquatic environments from excessive sedimentation, polluted surface runoff, and erosion.
• Habitat biodiversity: Riparian zones supply shelter and food for many aquatic animals and shade that limits stream temperature change.
• Climate change: Climate change is bringing warmer temperatures and drier conditions, as well as potential shifts in the amount and timing of precipitation. Precipitation is a particularly important driver of the riparian zone. Warmer and drier conditions also stress native riparian plant communities while giving a competitive advantage to some invasive plants.
• Water quality: Riparian vegetation influences light penetration, soil health, water quality, air and water temperatures, and interactions between aquatic and terrestrial zones.

Riparian areas are characterized by high water tables and are subject to periodic flooding. They may be natural or engineered for soil stabilization or restoration. Riparian areas are complex, delicate, and serve essential ecological functions. Some of the impacts that are important to be aware of include habitat loss, invasive species, and disturbance. It is therefore important to recognize threats to riparian systems in order to take management actions to mitigate damage and/or protect these areas.