Josiah Parkes (1793–1871) was an English civil engineer, inventor of a deep drainage system.
The brother of Joseph Parkes, and third son of John Parkes, a manufacturer, he was born at Warwick on 27 February 1793. He was educated at Charles Burney's school at Greenwich.
At the age of 17 Parkes started to work in his father's mill; in 1820 the factory at Warwick closed, and Parkes moved to Manchester, where he knew William Henry and John Dalton. He worked on inventions for the prevention of smoke, and then took up a new process for refining salt, near Woolwich. On 11 March 1823 he was chosen an associate of the Institution of Civil Engineers, and became a member on 26 December 1837.
In 1825 Parkes removed to Puteaux-sur-Seine and set up in business; he was often visited by Louis-Philippe, then the Duc d'Orléans. He took part in the July Revolution of 1830 in Paris, but lost his business and he returned to England.
For Mr. Heathcote of Tiverton, Parkes carried out a plan for draining a part of Chat Moss, Lancashire, which he tried to cultivate by using steam power. The steam cultivation was a failure. Parkes, however, observed the deep cuttings on the bog, and found that deep drains began to run after wet weather, not from the water above, but from rising water. Draining the stagnant moisture from about a metre below the surface had a marked effect on the soil. Parkes's views replaced the convention wisdom of the time, of James Smith of Deanston.