Victoria: Port Phillip Bay (Point Lonsdale to Point Nepean)

Introduction

Port Phillip Bay is a spacious embayment with an area of 1,950 sq km, a coastline 256 km long, and a narrow entrance from Bass Strait, Port Phillip Heads, 3.2 km wide at high tide, through which strong tidal currents (up to 4 m/s) maintain a deeply scoured channel known as The Rip. Because it is almost landlocked, Port Phillip Bay is rather like a marine lake. The northern part is a saucer-shaped basin with a maximum depth of 24 m, but the southern part is shallow, with extensive shoals exposed at low tide between deeper tidal channels that converge towards Port Phillip Heads (Keble 1946). Tide ranges are small (less than a metre at springs): high tides arrive in Bass Strait and are transmitted in through Port Phillip Heads, and then up to Williamstown, arriving more than three hours after passing Point Lonsdale Jetty. Ocean swell entering Port Phillip Heads is quickly diffracted and weakened, and away from the entrance waves are generated entirely by winds that blow...