Certain areas have been identified as sensitive regional areas, which are deemed particularly sensitive to the detrimental effects of nutrients, pathogenic organisms, organic chemicals and other substances that may be present in effluent from onsite wastewater system, and which are in need of special protection from such effects due to the unique and irreplaceable value of the resource, such as a public water supply, fisheries habitat and/or public recreation area. Standards for siting and design of onsite wastewater systems of this manual are established to enhance the wastewater treatment capability of onsite wastewater system, and thereby reduce the potential for adverse effects to critical resources. In areas designated as sensitive regional areas, the standards of this manual shall supersede minimum standards wherever applicable. The city will adopt the same areas as sensitive regional areas that have been identified by the South Dakota Department of Environment and Natural Resources. When specific evidence suggests questionable subsurface conditions exist, additional hydrological, geological, engineering or other information provided by a registered professional engineer or geologist may be required to be submitted by the applicant. The final determination shall be made by the Director.