<P> In Shrewsbury, boat trips around the loop of the town centre are at present provided by the Sabrina and depart from Victoria Quay near the Welsh Bridge during the summer . </P> <P> The river becomes tidal at Maisemore, on the West Channel just north of Gloucester, and at Llanthony Weir on the East Channel . The tidal river downstream from Gloucester is sometimes referred to as the Severn Estuary, but the river is usually considered to become the Severn Estuary after the Second Severn Crossing near Severn Beach, South Gloucestershire (the point to which the jurisdiction of the Gloucester Harbour Trustees extends), or at Aust, the site of the Severn Bridge . </P> <P> The Severn Estuary extends to a line from Lavernock Point (south of Cardiff) to Sand Point near Weston - super-Mare . West of this line is the Bristol Channel . In the Severn Estuary (or the Bristol Channel in the last two cases, depending where the boundary is drawn) are the rocky islands called Denny Island, Steep Holm and Flat Holm . </P> <P> The estuary is about 2 miles (3 km) wide at Aust, and about 9 miles (14 km) wide between Cardiff and Weston - super-Mare . </P>

Where does the severn estuary become the bristol channel
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