Iowa Admin. Code r. 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, department 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. Department 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 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.
Notes
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
(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 .