The River Ribble has the third-largest tides in England, with tides that run at and a tidal range at the mouth of the river of during spring tides. Since River Ribble dredging ceased, the estuary is filling up with sand and is developing a meandering path, depending on the tides and river runoff. In addition, many tributaries flow into the main channel including the Savick Brook/Ribble Link, while the River Douglas, has a significant influence both on sediment transport and hydrodynamics of the estuary.