Uses downstream of dams

Uses downstream of dams.

(1) General. Adequately designed, constructed and maintained dams provide reduced damages and relief from flooding for developed areas. Areas downstream of dams shall be zoned and regulated by municipalities with floodplain zoning ordinances in compliance with the standards in this section, to reduce potential loss of life and property located downstream of the dams. Except as provided in sub. (2) , areas downstream of all dams shall be delineated on floodplain maps in accordance with s. NR 116.09 (1) (b) 5. Flood studies and related mapping, completed and adopted prior to August 1, 2001, which calculated flood flow attenuation based on the existence of the dam structures within the contributing basin, may continue to use the dam in-place, no failure, profile.

(2) Exemptions. All dams having a structural height of 6 feet or less, or a storage capacity of 15 acre feet or less, and all dams having a structural height of more than 6 feet but less than 25 feet with a storage capacity of less than 50 acre feet are exempt from the requirements of this section unless the department determines pursuant to s. 31.19 , Stats., that the dam is likely to endanger life, health or property.

(3) Compliant dams.

(a) A dam is considered compliant if all the following requirements are met:

1. The dam is structurally adequate to meet the conditions in ss. NR 333.05 (2) (k) and 333.07 (3) (b) .

2. The dam is hydraulically adequate to meet the standards in s. NR 333.07 (1) .

3. The dam has been certified by a professional engineer, registered in Wisconsin, to meet the requirements of subds. 1. and 2.

4. Written assurance of the dam owner’s ability to operate and maintain the dam in good condition is obtained from the dam owner.

5. An emergency action plan to minimize loss of human life has been developed for the area downstream of the dam based on the assumption that the dam fails during the regional flood.

6. The department reviews and approves the material submitted under subds. 1. to 5.

2.

4. Written assurance of the dam owner’s ability to operate and maintain the dam in good condition is obtained from the dam owner.

5. An emergency action plan to minimize loss of human life has been developed for the area downstream of the dam based on the assumption that the dam fails during the regional flood.

6. The department reviews and approves the material submitted under subds. 1. to 5.

(b) Developed areas downstream of compliant dams shall be zoned and regulated as follows:

1. For high hazard dams, assuming that the dam is nonexistent during the regional flood.

2. For significant or low hazard dams, assuming the dam fails during the regional flood.

(c) Undeveloped areas downstream of a compliant dam shall be zoned and regulated assuming that the dam fails during the regional flood.

(4) Noncompliant dams.

(a) If an existing dam does not meet the standards in sub. (3) (a) , the dam is considered noncompliant.

(b) Both developed and undeveloped areas downstream of a noncompliant dam shall be zoned and regulated assuming that dam failure occurs during the regional flood.

(c) The regional flood profile of the area downstream of the dam shall be calculated in accordance with s. NR 333.05 (2) (b) .

(5) Construction of new dams.

(a) Dams constructed after August 1, 2001, shall be considered compliant if the requirements in sub. (3) (a) are met.

(b) Developed areas downstream of the construction of a new dam shall be zoned and regulated as if the dam does not exist until construction is 100% complete and all the conditions of sub. (3) (a) are met.