If, upon the completion of all public and private improvements in a subdivision, it is found that the construction of buildings is not feasible due to unsatisfactory subsurface conditions, or for any other reason, and such lots are left vacant by the owner, the lots and parkways shall be improved by grading, spreading four inches (4") of topsoil and fully seeded. The owner of the adjacent property shall be responsible for the maintenance of the parkways. (1978 Code § 7-4-4)