He was employed on the trigonometrical survey at Oakingham, Berkshire (1806), until he received a commission as second lieutenant in the Royal Engineers on 1 July 1807.
Vetch was then sent to the Barbary Coast, and went on from Tangier to Tetuan to report on the capabilities of the country to furnish engineering supplies.
[1] In March 1812 Vetch left Cadiz for Elvas, sailing up the Guadiana River with a company of sappers and miners to take part in the siege of Badajos.
On the evening of 6 April, when the final assault took place, he made a lodgment with three hundred men in the ravelin of San Roque, and entered Badajos with the victorious army.
[1] From 1814 to 1820 Vetch commanded a company of sappers and miners, first at Spike Island in Cork Harbour, where he was employed on the construction of Fort Westmoreland, and afterwards at Chatham.
He went to Mexico, and managed the Real del Monte silver mines, associated with John Taylor,[2] and those of Bolaños companies.
[1] In 1844, 1845, and 1846 Vetch was examined by the Commissioners Upon the Subject of Harbours of Refuges, and at their request wrote a report on wrought iron frameworks in the construction of piers and breakwaters.
In the same year he proposed an extended water supply for the London metropolis, and in 1850 designed a system of drainage for Southwark.
Vetch was author of:[1] Reports were published by Vetch between 1847 and 1859 on the following harbours: Ramsgate, the Tyne, Cork, Wexford, the Isle of Man, Holyhead, Port Patrick, and Donaghadee, Galway, Portsmouth, Table Bay, Port Natal, Point de Galle.
[1] Feeling the want of a good map of Mexico, Vetch accumulated astronomical and barometrical observations while there, measured several short base-lines, and triangulated a large tract of country.
Twelve years later Ferdinand de Lesseps published his scheme, printing Vetch's opinions as an appendix to his work.