In another era I often flew Cessna singles with students from Essendon to various training areas. Usual initial track was Essendon direct to Westgate Bridge. The nearby Marylebone River was parallel to our track most of the time. My advice to students was if an engine failure happened and it wasn't possible to comfortably glide to Moonee Valley or Flemington Racecourses, then a ditching into the river was the way to go rather than risk trying to land at local sports grounds. Also not far to swim to the banks of the river.