Iowa Admin. Code r. 567-73.3

Current through Register Vol. 47, No. 11, December 11, 2024

Rule 567-73.3 - Regulated dams

(1)Thresholds. Dams meeting any of the following thresholds shall be regulated by the department:

a. A dam with a height of at least 25 feet and a storage of 15 acre-feet or more at the top of the dam elevation; or

b. A dam with a storage of 50 acre-feet or more at the top of the dam elevation and a height of at least 6 feet; or

c. A dam that is assigned a hazard potential of high hazard.

(2)Exceptions. Road embankments or driveways with culverts are exempt unless such structure serves, either primarily or secondarily, a purpose commonly associated with dams, such as the temporary storage of water for flood control.

(3)New construction. Before construction begins, approval is required for construction of any dam meeting the thresholds of a regulated dam. The proposed dam must meet the criteria outlined in this chapter.

(4)Existing dams.

a. Approval is required for:

(1) Modification, repair, alteration, breach, abandonment, or removal of any existing dam or appurtenant structure beyond the scope of ordinary maintenance if the height of the dam or storage of the dam exceeds the applicable thresholds in this rule.

(2) Any change in operating procedures if the height of the dam or storage of the dam exceeds the applicable thresholds in this rule.

b. Spillway reconstruction, changes in normal water level, and modification of the dam embankment or spillway are examples of modifications that require approval. The dam must meet the criteria outlined in this chapter. Dams found to be unsafe according to rule 567-73.33 (455B) shall be repaired or removed.

(5)Required upgrades. Improvements may be required for existing dams in order to reduce the risk of a dam failure.

a. Existing dams assigned a high hazard potential or significant hazard potential that have been inspected or analyzed and found not to meet the criteria in this chapter will be required to meet the requirements outlined in this chapter for the appropriate hazard potential.

b. Existing dams assigned a low hazard potential that have been inspected or analyzed and found to have a significant hazard potential or high hazard potential shall be required to be upgraded to meet the requirements outlined in this chapter for the appropriate hazard potential.

Iowa Admin. Code r. 567-73.3

Amended by IAB September 8, 2021/Volume XLIV, Number 5, effective 10/13/2021