Section 58.01.02.102 - DESIGNATION AND REVISION OF BENEFICIAL USESWhen designating or revising beneficial uses for a water body, the Department shall consult with the basin advisory group and the watershed advisory group with the responsibilities for the water body described in Chapter 36, Title 39, Idaho Code. After consultation, the Director shall identify the designated beneficial uses of each water body in these rules pursuant to the rulemaking and public participation provisions of Chapter 52, Title 67, Idaho Code.
01.Designation of Beneficial Uses. Beneficial uses shall be designated in accordance with Section 39-3604, Idaho Code, taking into consideration the uses set forth in Section 100, and such physical, geological, chemical, and biological measures as may affect the surface water. Beneficial uses are designated according to water body unit unless designated otherwise. Use designations are made for each water body or segment whether or not they are being attained or are fully supported at the time of designation. a. In designating beneficial uses, which a water body can reasonably be expected to attain, the Department shall consider: i. Existing uses of the water body;ii. The physical, geological, hydrological, atmospheric, chemical and biological measures that affect the water body;iii. The beneficial use attainability measures identified in Section 39-3607, Idaho Code;iv. The economic impact of the designation and the economic costs required to fully support the beneficial uses;v. The attainment and maintenance of the water quality standards of downstream waters, including the waters of downstream states;vi. Adopting subcategories of a beneficial use and setting the appropriate criteria to reflect varying needs of such subcategories of beneficial uses, for instance, to differentiate between cold water and warm water fisheries;vii. At a minimum, that beneficial uses are deemed attainable if they can be achieved by the imposition of effluent limits required under sections 301(b) and 306 of the federal Clean Water Act and cost-effective and reasonable best management practices for nonpoint source control; andviii. Designating seasonal beneficial uses as an alternative to reclassifying a water body or segment thereof to uses requiring less stringent water quality criteria. If seasonal beneficial uses are adopted, water quality criteria may be adjusted to reflect the timing of the beneficial use, e.g., salmonid spawning. However, seasonal beneficial uses and their criteria shall not preclude the attainment and maintenance of a more protective beneficial use at other times.b. In no case shall waste transport or waste assimilation be a designated beneficial use for a water body.02.Revision of Beneficial Uses.a. Designated beneficial uses shall be reviewed and revised when such physical, geological, hydrological, atmospheric, chemical or biological measures indicate the need to do so. Designated beneficial uses may be revised or removed if the designated beneficial use is not an existing use, and it is demonstrated that attaining the designated beneficial use is not feasible due to one of the following factors:i. Naturally occurring pollutant concentrations prevent the attainment of the use;ii. Natural, ephemeral, intermittent or low flow conditions or water levels prevent the attainment of the use unless these conditions may be compensated for by the discharge of sufficient volume of effluent discharges without violating state water conservation requirements to enable uses to be met;iii. Human caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place;iv. Dams, diversions or other types of hydrologic modifications preclude the attainment of the use, and it is not feasible to restore the water body to its original condition or to operate such modification in a way that would result in the attainment of the use;v. Physical conditions related to the natural features of the water body, such as the lack of a proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, preclude attainment of aquatic life protection uses; orvi. Controls more stringent than those required by sections 301(b) and 306 of the federal Clean Water Act would result in substantial and widespread economic and social impact.b. Designated beneficial uses may not be removed if:i. They are existing uses unless a use requiring more stringent criteria is added; orii. Such uses can be attained by implementing effluent limits required under sections 301(b) and 306 of the federal Clean Water Act and by implementing cost-effective and reasonable best management practices for nonpoint source control.c. Where existing water quality standards specify designated uses less than those which are presently being attained, the Department shall revise its standards to reflect the uses actually being attained.d. A use attainability analysis is a structured scientific assessment of the factors affecting the attainment of the use which may include physical, chemical, biological, and economic factors as described in Subsection 102.02.a. A use attainability analysis must be conducted whenever:i. The Department designates uses for a water body that do not include the protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water; orii. The Department acts to remove a designated use which provides for protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water; to remove a subcategory of such uses; or to designate subcategories of such uses which require less stringent criteria than previously applicable.e. A use attainability analysis is not required under this rule whenever: i. The Department designates beneficial uses which include protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water; orii. The Department removes a beneficial use that does not include the protection and propagation of fish, shellfish, and wildlife and provides for recreation in and on the water.Idaho Admin. Code r. 58.01.02.102