While looking for early references to "Springs" near Tullamarine, I came across an 1839 article about the Port Phillip District's harbours and rivers.
PORT PHILLIP

Having discovered that the Maribyrnong River was first called the Arndell by Hume and Hovell in 1924, I wondered what I'd find if I googled, ARDNELL RIVER, MELBOURNE, and found a fantastic article about the history of Melbourne's western suburbs with some great historic photos.
MELBOURNE'S 180TH BIRTHDAY

Unfortunately the wrong source was consulted about the Arndell River, as the Arndell was confused with the Exe, BUT the origin of the name (as confirmed below) was explained.

Hovell, William Hilton (1786–1875)

by T. M. Perry

This article was published in Australian Dictionary of Biography, Volume 1, (MUP), 1966

William Hilton Hovell (1786-1875), sailor, explorer and settler, was born on 26 April 1786 at Yarmouth, Norfolk, England. He went to sea as a boy and by 1808 commanded a vessel trading with South America. In London on 10 May 1810 he married Esther, a daughter of Surgeon Thomas Arndell, and in November 1811 applied for permission to settle in New South Wales. (etc.)