Idaho Administrative Code
Title IDAPA 37 - Water Resources, Department of
Rule 37.03.06 - SAFETY OF DAMS RULES
Section 37.03.06.035 - DESIGN REPORTS, DRAWINGS, AND SPECIFICATIONS

Universal Citation: ID Admin Code 37.03.06.035

Current through September 2, 2024

The following provisions shall apply when submitting plans, drawings, reports, and specifications for dams to the Director for design review and approval, prior to commencing construction.

01. Submission of Duplicate Plans, Drawings and Specifications. Any owner desiring to construct, enlarge, alter, or repair any dam, shall submit duplicate plans, drawings and specifications prepared by an engineer for the proposed work to the Director with required fees for approval prior to commencing construction.

02. Applying for and Obtaining Written Approval. Construction of a new dam, or the enlargement, alteration, or repair of such shall not commence until the owner has applied for and obtained written approval of the plans, drawings, and specifications from the Director.

03. Preparation and Submission of Plans. Plans and drawings shall be of a sufficient scale with an adequate number of views showing proper dimensions, so that the plans and drawings may be readily interpreted and so that the structure and appurtenances can be built in conformance with the approved design. Plans and drawings shall be submitted in both printed and digital format, with the printed version consisting of paper size eleven by seventeen (11 x 17) inches. After reviewing the plans, the Director will notify the owner of any required changes.

04. Information Included with Plans. Plans for new dams or the enlargement, alteration, or repair of such shall include as much of the following information as determined necessary by the Director to adequately describe the enlargement, alteration, or repair and the effect on the existing structure or its appurtenances:

a. A topographic map of the project site showing the location of the proposed construction by section, township and range, and location of all borings, test pits, borrow pits and other locations of samples obtained for field or laboratory testing;

b. A profile depicting the locations, elevations, and depths of borings or test pits, including the visual illustration of logs of bore holes, test pits, or borrow pits;

c. A cross-section of the structure at maximum section showing elevation and width of crest, slopes of upstream and downstream faces, thickness of riprap, zoning of earth embankment, location of cutoff and bonding trenches, elevations and dimensional heights, size and type of conduits, valves, operating mechanism, and dimensions of all other essential elements deemed to be necessary for properly constructing the approved design;

d. Detailed drawings showing plans, cross and longitudinal sections of appurtenant features such as but not limited to the spillway, training walls, outlet conduits, valves, gates, trash rack, and control works;

e. A curve or table showing the capacity of the reservoir or tailings impoundment in acre-feet vs. gauge height referenced to a common project datum and the computations used in making such determinations;

f. A curve or table showing the outlet discharge capacity in cubic feet per second vs. gauge height of reservoir storage level, and the computations used in making such determinations;

g. A curve or table showing the spillway discharge capacity in cubic feet per second vs. gauge height of the reservoir or flood surcharge level above the spillway crest and the computations used in making such determinations;

h. Detailed drawings of spillway structure(s), including cross-sections of the channel entrance and exit points to and from the spillway and a spillway profile;

i. Plans for flow measuring devices capable of providing an accurate determination of the flow of the stream above or below the reservoir, and a permanent reservoir or staff gauge near the outlet of the reservoir plainly marked in feet and tenths of a foot referenced to an approved datum; and

j. Plans or drawings of instruments recommended by the owner or engineer to monitor the performance of the dam to assure safe operation, or as may be required by the Director as deemed necessary to monitor any structure for benefit of public safety regardless of size.

05. Specifications. The engineer shall prepare specifications that include instructions for construction of the approved design in accordance with accepted engineering and industry standards of care, including provisions for adequate observation, inspection, and control of the work by an engineer during the period of construction.

06. Changes to the Approved Design. The approved design shall not be materially changed without prior written consent of the Director. Design changes which may affect the stability, size, or integrity of the structure, while construction is underway, shall be submitted for the Director's review and approval. In emergency situations, the owner shall make the required alterations or repairs necessary to relieve the emergency, and subsequently notify the Director of all alterations or repairs implemented.

07. Inspections. The owner shall allow inspections by the Department to assure the dam and appurtenant structures are constructed in conformance with the approved plans and specifications, or as may be revised by the engineer and approved by the Director if there are unforeseen conditions discovered during site preparation or construction which potentially jeopardize the future integrity and safety of the project works. The Department may request of the owner that certain stages of construction not proceed without inspection and approval by the Director.

08. Inspection, Examination and Testing of Materials. All materials and workmanship shall be subject to review, inspection, examination, or testing by the Director.

09. Rejection of Defective Material. The Director may order the owner or engineer to reject defective material. The owner shall correct rejected workmanship and replace rejected material with approved material.

10. Suspension of Work. The Director may order the engineer to suspend any work that is or is likely to be subject to damage by inclement weather conditions.

11. Responsibility of Engineer. These provisions shall not relieve the engineer of their responsible charge to assure that construction is accomplished in accordance with their approved plans and specifications as mandated by Sections 54-1202(10) and (15), Idaho Code, or to unilaterally suspend work as deemed necessary.

12. Design Report. Owners proposing to construct, enlarge, alter, or repair a dam shall submit an engineering or design evaluation report to accompany the plans and specifications. The engineering report shall include as much of the following information as necessary to present the technical basis for the design and to describe the analyses used to evaluate performance of the structure and appurtenances.

a. All technical reference(s), equations, calculations, and assumptions used in the design.

b. Hydrologic data used in determining runoff from the drainage areas, reservoir flood routing pertinent to the project location, and hydraulic evaluations of the outlet(s) and the spillway(s) as may be required for approval of the design plans and specifications.

c. Investigation of site and subsurface conditions, to include the engineering properties of the foundation area and of each type of material to be encountered or used in the construction of the project works.

d. A stability analysis, including an evaluation of overturning, sliding, slope, and foundation stability;
i. An evaluation of seismic design loads may be included in the stability analysis for all dams as deemed necessary by the Director for benefit of public safety. The evaluation required for the design of large dams or high hazard structures shall use the maximum ground acceleration which could affect the dam. In the absence of a site-specific seismic hazard analysis, the Director may accept seismic analyses that reference published seismic hazard maps which determine seismic loads estimated for seismic events corresponding to a return interval of two percent (2)% in fifty (50) years.

ii. Seismic analyses may be waived by the Director for new or existing dams if the consequence of failure is demonstrated to be sufficiently low or the critical features of design are demonstrated to be sufficiently conservative to allow minor deformation(s) without releasing the contents of the impounding structure.

e. Geologic description of the dam and reservoir area, including evaluation of landslide potential near the dam;

f. Engineering properties and the weathering characteristics of the contents proposed for storage in the impoundment, if applicable;

g. Other information which would aid in evaluating the safety of the design.

13. Additional Information/Waiver. The Director may require the filing of such additional information which in their opinion is necessary for the benefit of public safety or waive any requirement in these rules if available data demonstrates that it is unnecessary.

14. Alternate Plans. The Director may accept plans and specifications for dams, or portions thereof prepared for other agencies which are determined to meet the requirements of Rule 35, including but not limited to the following:

a. An operation plan; or

b. An emergency action plan to help protect or mitigate the consequences of a dam failure on downstream life and property.

Effective March 30, 2023

Disclaimer: These regulations may not be the most recent version. Idaho may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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