How Do British Rivers Typically Reach the Sea?

Most British rivers enter the sea via an estuary—a wide, funnel-shaped mouth formed by river current and tidal action. Sediment builds sandbars or mudflats, creating tidal inlets that allow water and aquatic life to move between river and sea.

Some, like the Thames, enter through a ria (drowned river valley), forming long, narrow, steep-sided inlets. A few, like the Severn, form a delta—a fan-shaped deposit where sediment accumulates as the current slows.