Tunnels under pavements shall not be permitted except by permission of the city administrator or his designee. Where pipes or cables are placed under main thoroughfares, concrete streets, state highways, first grade asphalt streets, or wherever designated by the city administrator or his designee, such work shall be done by jacking or boring casings under street surfaces and placing said pipes or cables inside of the casing. (Ord. 751, 12-18-2000)