Height limits. The height limitations in this chapter shall not apply to the following structures, provided that such structures are compatible with uses in the immediate vicinity: silos, barns and other agricultural structures; church spires; cupolas; domes; monuments; water towers; fire observation towers; electric transmission facilities and supporting structures; windmills; chimneys; smokestacks; derricks; conveyors; flagpoles; masts; aerials; solar energy facilities; and similar structures required to be placed above the roof level and not intended for human occupancy; provided, however, that the height of any tower or similar structure shall not exceed the distance from the nearest property line to the base of the tower or structure. Such features, however, shall be erected only to such height as is necessary to accomplish the purpose they are to serve.