Land which the approving authority finds to be in areas having severe or moderate soil characteristics, particularly as the land relates to flooding, improper drainage, steep slopes, rock formations, soil conditions, adverse topography or other features which can reasonably be expected to be harmful to the health, safety and general welfare of the present or future inhabitants of the development and/or its surrounding areas shall not be subdivided, and site plans shall not be approved unless adequate and acceptable methods are formulated by the developer to solve the problems by methods meeting the requirements of this ordinance and all other regulations.