During the Miocene era, what is now the catchment area of the lake was on the western side of an uplifted area that functioned as a continental divide, with streams on the western side flowing into the Congo River basin and streams on the eastern side flowing to the Indian Ocean.
In 1843, he [Arthur Denny] married Mary Ann Boren; together they had six children: Louisa Catherine Frye, Margaret Leona Denny, Rolland Herschell Denny, Orion Orvil Denny, Arthur Wilson Denny, and Charles Latimer Denny.