Iowa Administrative Code

71.1(1) Rural areas. In rural areas, projects in or on the floodplain of any stream draining ten or more square miles at the downstream end of the project site. 71.1(2) Urban areas. In urban areas, projects in or on the floodplain of any river or stream draining two or more squar…

approved local floodplain regulation shall not be effective until it has been reviewed and approved by the department in accordance with the following procedures. 71.3(1) Duty of local government to notify department of each variance request. After receipt of each request for var…

567—71.1(455B), the following activities do not require approval pursuant to this title by the department to construct in a floodplain: 71.4(1) Rural bridges/culverts/road embankments and associated work. Construction, maintenance, or use of bridges, culverts, temporary stream cr…

567—70.6(17A,455B,481A). If the applicant is denied a permit to channelize a protected stream, the applicant may appeal to the environmental protection commission. The appeal will normally be heard by an administrative law judge but the applicant may request that the commission h…

construction, operation, and maintenance of bridges, culverts, and road embankments: 72.1(1) Bridges and road embankments affecting low damage potential areas. For bridges and road embankments affecting floodway or floodplain areas having a low flood damage potential, the followi…

and stream crossings: 72.10(1) Protection. Pipeline river or stream crossings shall be sufficiently buried in the stream bed and banks or otherwise sufficiently protected to prevent rupture. 72.10(2) Overflow and velocities. Pipeline river or stream crossings shall be constructed…

construction: 72.11(1) Structures, obstructions, or deposits. a. Location. Miscellaneous structures, obstructions, or deposits shall be located outside of the floodway or demonstrate that the construction shall not result in a rise in upstream water surface elevations. b. Protect…

feeding operation structures: 72.13(1) Confinement feeding operation structures located on the floodplain of a major water source. As required by 567—Chapter 65, confinement feeding operation structures shall not be constructed on land that would be inundated by Q100 and is adjac…

DIVISION II GENERAL CRITERIA

72.2(1) Percent reduction in length. a. Streams draining over 100 square miles. For streams (other than protected streams) draining more than 100 square miles, no more than a 10 percent reduction in the original length of the existing channel through any contiguous parcel(s) of t…

to the following conditions: 72.30(1) Maintenance. The applicant and any successor in interest to the real estate on which the project or activity is located shall be responsible for proper maintenance. 72.30(2) Responsibility. No legal or financial responsibility arising from th…

561—Chapter 10. The contents of a petition for waiver shall include information pursuant to 561—10.9(17A,455A). [ARC 9210C, IAB 5/14/25, effective 6/18/25]

relation of hydrologically connected streams to protected streams: 72.32(1) Protected streams variance procedure. The variance shall be requested as part of the permit application and review process provided for in 567—70.3(17A,455B,481A) to

DIVISION III PROTECTED STREAM DESIGNATION PROCEDURE

and dikes: 72.4(1) Agricultural levees or dikes. a. Level of protection. The permanent height of agricultural levees or dikes normally shall be limited so that overtopping will occur due to discharges from Q10 to Q25 with the more comprehensive levee system being permitted the gr…

72.5(1) Minimum protection levels. The minimum level of flood protection for a building depends on the damage potential of the building and contents. “Maximum” and “high” damage potential classifications are defined in 567—Chapter 70. Criteria for determining minimum levels of pr…

72.50(1) Protected streams defined. Protected streams shall include streams designated as protected streams pursuant to the procedures of 567—72.51(455B), which upon designation will be listed in 72.50(2). Streams hydrologically connected to protected streams are not protected st…

72.51(1) Eligible petitioners. Any state agency, governmental subdivision, association or interested person may petition the commission, according to the rules of this division, to designate a stream as a protected stream. However, if the stream had been the subject of a similar …

from the list of protected streams in 72.50(2) shall be the same as the rules for designation of a stream as a protected stream, except that all notices, investigations and reports shall be addressed to the issue of declassification. [ARC 9210C, IAB 5/14/25, effective 6/18/25] Th…

to water supply and wastewater treatment facilities: 72.6(1) Location. Water supply and wastewater treatment facilities shall be located outside of the floodway or demonstrate that the construction shall not result in a rise in upstream water surface elevations. 72.6(2) Flood pro…

72.7(1) Location. Sanitary landfills shall be located outside of the floodway or demonstrate that the construction shall not result in a rise in upstream water surface elevations. 72.7(2) Flood protection. Flood protection for the active working portion of the sanitary landfill s…

floodplain: 72.8(1) Location. Any permanent structures, obstructions, or deposits shall be located outside of the floodway or demonstrate that the construction shall not result in a rise in upstream water surface elevations. 72.8(2) Flood protection. Any permanent structures, obs…

devices: 72.9(1) Overflow. Stream protective devices shall be constructed in a manner which will not cause premature overbank flow. 72.9(2) Velocity. Increased velocities resulting from the construction, operation, and maintenance of stream protective devices shall be limited so …

construction and maintenance of dams. Any person who desires to construct, repair, modify, abandon, or remove a dam has a responsibility to determine whether approval is required from the department prior to undertaking any such work. [ARC 9211C, IAB 5/14/25, effective 6/18/25]

or removal. 73.10(1) Application process. Application materials are provided by the department. The application shall be submitted by or on behalf of the person or persons who will be the future dam owner or owners. The application shall be signed by the applicant or a duly autho…

73.11(1) A water storage permit shall be required for all regulated dams in order to legally impound water. No water shall be impounded by a dam or reservoir prior to issuance of a water storage permit. 73.11(2) Application for a dam construction permit shall constitute applicati…

DIVISION III CRITERIA FOR APPROVAL

73.15(1) Required findings. The department shall approve the construction, repair, modification, abandonment, or removal of a dam only after finding that the project is designed in accordance with accepted engineering practice and methods, and in a manner consistent with the appl…

shall include information showing the nature and extent of lands, easements, and rights-of-way that the applicant has acquired or proposes to acquire to satisfy the following criteria: 73.16(1) Ownership or perpetual easements shall be obtained for the area to be occupied by the …

73.17(1) Emergency action plan required. All high hazard dams shall be required to have an approved emergency action plan on file with the department. The plan shall include the following: a. A statement of purpose; b. A project description; c. An emergency response process; d. A…

constructed or modified so that the ordinary high water of the lake, pond, or reservoir created by the dam is closer than the following distances from a confinement feeding operation structure unless a secondary containment barrier according to 567—subrule 65.15(17) is in place. …

73.19(1) Hydrology and hydraulic calculations. Hydrology and hydraulic calculations shall be submitted in the design report documenting the methods and analysis followed in modeling software selection, inflow design hydrograph determination, and reservoir routing. The hydrology a…

“Abandonment” means to render a dam nonimpounding by dewatering and filling the reservoir created by that dam with solid materials and by diverting the natural drainage around the site. “Acre-foot” means a volume of water that would cover one acre of land one foot deep, equal to …

73.20(1) Spillways shall be designed to operate safely for the life of the structure and at the discharges and pressures that would be experienced under all flow conditions, including the freeboard design flood. 73.20(2) Spillways shall be provided with a means of piping and seep…

73.21(1) The applicant shall document the engineering standards and design references used for dam embankment design. Drawing details, as necessary, shall be provided showing embankment slopes, required additional fill for anticipated settlement, top width, foundation preparation…

other movable structures that must operate or be operated during times of flood or to provide a minimum downstream release rate. Development of the operating plan is considered part of the design process. An operating plan shall include, at a minimum, the following items: 73.22(1…

and removal of all or a significant portion of the embankment. A dam may be abandoned by rendering a dam nonimpounding by dewatering and filling the reservoir with solid materials and by diverting the natural drainage around the site. 73.23(1) Removal requirements. A dam removal …

DIVISION IV DAM OWNERSHIP, INSPECTIONS, AND ENFORCEMENT

73.3(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 o…

73.30(1) Operation and maintenance required. The intent to permanently cease or cause to cease all acts of construction, operation, and maintenance of a dam is prohibited. If any person wishes to be relieved of the responsibilities inherent in the ownership or control of a dam st…

73.31(1) Scope of dam safety inspection program. Dams subject to inspection under these rules are regulated dams as defined in this chapter. The scope of department staff field inspections normally is limited to visually observable features of dams and their appurtenant structure…

73.32(1) When approval is required. A separate approval is required to temporarily or permanently raise or lower the normal level of water impounded by a regulated dam unless the raising and lowering has been authorized as part of an approved operating plan. Such approval shall b…

73.33(1) Procedures for designation of a dam as unsafe. a. Department report. If after inspection or other investigation the department determines that a dam is unsafe, a report shall be prepared. Copies of the report shall be provided to the dam owner and any other person whom t…

department shall be assigned a hazard potential. Anticipated future land and impoundment use shall be considered in the determination of hazard potential. The hazard potential shall be determined using the following criteria: 73.4(1) Low hazard. A dam shall be classified as “low …

DIVISION II APPROVAL PROCESS

This rule is intended to implement Iowa Code sections 17A.3, 455A.6, and 573.12(13). [ARC 9932C, IAB 1/7/26, effective 12/16/25] [Filed 9/26/88, Notice 8/10/88—published 10/19/88, effective 11/23/88] [Filed 4/26/91, Notice 2/20/91—published 5/15/91, effective 6/19/91] [Filed Emer…

81.1(1) In addition to the definitions, references, and abbreviations in 567—Chapter 40, the following definitions shall apply to this chapter: “Activated sludge system” means a biological wastewater treatment process in which a mixture of wastewater and sludge floc, produced in …

c. Renewal application and fee. (1) Certification renewal applications shall be made available to certified operators on the department’s website at www.iowadnr.gov prior to the certificate expiration date. (2) All renewal applications shall be digitally submitted, postmarked, or…