Utah Admin. Code R315-319-74 - Structural Integrity Criteria for New CCR Surface Impoundments and Any Lateral Expansion of a CCR Surface Impoundment

(a) The requirements of Subsections R315-319-74(a)(1) through (4) apply to all new CCR surface impoundments and any lateral expansion of a CCR surface impoundment, except for those new CCR surface impoundments that are incised CCR units. If an incised CCR surface impoundment is subsequently modified, e.g., a dike is constructed, such that the CCR unit no longer meets the definition of an incised CCR unit, the CCR unit is subject to the requirements of Subsections R315-319-74(a)(1) through (4).

(1) No later than the initial receipt of CCR, the owner or operator of the CCR unit shall place on or immediately adjacent to the CCR unit a permanent identification marker, at least six feet high showing the identification number of the CCR unit, if one has been assigned by the state, the name associated with the CCR unit and the name of the owner or operator of the CCR unit.

(2) Periodic hazard potential classification assessments.

(i) The owner or operator of the CCR unit shall conduct initial and periodic hazard potential classification assessments of the CCR unit according to the timeframes specified in Subsection R315-319-74(f). The owner or operator shall document the hazard potential classification of each CCR unit as either a high hazard potential CCR surface impoundment, a significant hazard potential CCR surface impoundment, or a low hazard potential CCR surface impoundment. The owner or operator shall also document the basis for each hazard potential classification.

(ii) The owner or operator of the CCR unit shall obtain a certification from a qualified professional engineer stating that the initial hazard potential classification and each subsequent periodic classification specified in Subsection R315-319-74(a)(2)(i) was conducted in accordance with the requirements of Section R315-319-74.

(3) Emergency Action Plan (EAP)

(i) Development of the plan. Prior to the initial receipt of CCR in the CCR unit, the owner or operator of a CCR unit determined to be either a high hazard potential CCR surface impoundment or a significant hazard potential CCR surface impoundment under Subsection R315-319-74(a)(2) shall prepare, and maintain a written EAP. At a minimum, the EAP shall:

(A) Define the events or circumstances involving the CCR unit that represent a safety emergency, along with a description of the procedures that will be followed to detect a safety emergency in a timely manner;

(B) Define responsible persons, their respective responsibilities, and notification procedures in the event of a safety emergency involving the CCR unit;

(C) Provide contact information of emergency responders;

(D) Include a map which delineates the downstream area which would be affected in the event of a CCR unit failure and a physical description of the CCR unit; and

(E) Include provisions for an annual face-to-face meeting or exercise between representatives of the owner or operator of the CCR unit and the local emergency responders.

(ii) Amendment of the plan.

(A) The owner or operator of a CCR unit subject to the requirements of Subsection R315-319-74(a)(3)(i) may amend the written EAP at any time provided the revised plan is placed in the facility's operating record as required by Subsection R315-319-105(f)(6). The owner or operator shall amend the written EAP whenever there is a change in conditions that would substantially affect the EAP in effect.

(B) The written EAP shall be evaluated, at a minimum, every five years to ensure the information required in Subsection R315-319-74(a)(3)(i) is accurate. As necessary, the EAP shall be updated and a revised EAP placed in the facility's operating record as required by Subsection R315-319-105(f)(6).

(iii) Changes in hazard potential classification.

(A) If the owner or operator of a CCR unit determines during a periodic hazard potential assessment that the CCR unit is no longer classified as either a high hazard potential CCR surface impoundment or a significant hazard potential CCR surface impoundment, then the owner or operator of the CCR unit is no longer subject to the requirement to prepare and maintain a written EAP beginning on the date the periodic hazard potential assessment documentation has been submitted to and has received approval from the Director and placed in the facility's operating record as required by Subsection R315-319-105(f)(5).

(B) If the owner or operator of a CCR unit classified as a low hazard potential CCR surface impoundment subsequently determines that the CCR unit is properly re-classified as either a high hazard potential CCR surface impoundment or a significant hazard potential CCR surface impoundment, then the owner or operator of the CCR unit shall prepare and submit to the Director a written EAP for the CCR unit as required by Subsection R315-319-74(a)(3)(i) within six months of completing such periodic hazard potential assessment.

(iv) The owner or operator of the CCR unit shall obtain a certification from a qualified professional engineer stating that the written EAP, and any subsequent amendment of the EAP, meets the requirements of Subsection R315-319-74(a)(3).

(v) Activation of the EAP. The EAP shall be implemented once events or circumstances involving the CCR unit that represent a safety emergency are detected, including conditions identified during periodic structural stability assessments, annual inspections, and inspections by a qualified person.

(4) The CCR unit and surrounding areas shall be designed, constructed, operated, and maintained with vegetated slopes of dikes except for slopes which are protected with an alternate form(s) of slope protection.

(b) The requirements of Subsections R315-319-74(c) through (e) apply to an owner or operator of a new CCR surface impoundment and any lateral expansion of a CCR surface impoundment that either:

(1) Has a height of five feet or more and a storage volume of 20 acre-feet or more; or

(2) Has a height of 20 feet or more.

(c)

(1) No later than the initial receipt of CCR in the CCR unit, the owner or operator unit shall compile the design and construction plans for the CCR unit, which shall include, to the extent feasible, the information specified in Subsection R315-319-74(c)(1)(i) through (xi).

(i) The name and address of the person(s) owning or operating the CCR unit; the name associated with the CCR unit; and the identification number of the CCR unit if one has been assigned by the state.

(ii) The location of the CCR unit identified on the most recent U.S. Geological Survey (USGS) 71/2 minute or 15 minute topographic quadrangle map, or a topographic map of equivalent scale if a USGS map is not available.

(iii) A statement of the purpose for which the CCR unit is being used.

(iv) The name and size in acres of the watershed within which the CCR unit is located.

(v) A description of the physical and engineering properties of the foundation and abutment materials on which the CCR unit is constructed.

(vi) A statement of the type, size, range, and physical and engineering properties of the materials used in constructing each zone or stage of the CCR unit; the method of site preparation and construction of each zone of the CCR unit; and the dates of construction of each successive stage of construction of the CCR unit.

(vii) At a scale that details engineering structures and appurtenances relevant to the design, construction, operation, and maintenance of the CCR unit, detailed dimensional drawings of the CCR unit, including a plan view and cross sections of the length and width of the CCR unit, showing all zones, foundation improvements, drainage provisions, spillways, diversion ditches, outlets, instrument locations, and slope protection, in addition to the normal operating pool surface elevation and the maximum pool surface elevation following peak discharge from the inflow design flood, the expected maximum depth of CCR within the CCR surface impoundment, and any identifiable natural or manmade features that could adversely affect operation of the CCR unit due to malfunction or mis-operation.

(viii) A description of the type, purpose, and location of existing instrumentation.

(ix) Area-capacity curves for the CCR unit.

(x) A description of each spillway and diversion design features and capacities and calculations used in their determination.

(xi) The construction specifications and provisions for surveillance, maintenance, and repair of the CCR unit.

(xii) Any record or knowledge of structural instability of the CCR unit.

(2) Changes in the design and construction. If there is a significant change to any information compiled under Subsection R315-319-74(c)(1), the owner or operator of the CCR unit shall update the relevant information and place it in the facility's operating record as required by Subsection R315-319-105(f)(13).

(d) Periodic structural stability assessments.

(1) The owner or operator of the CCR unit shall conduct initial and periodic structural stability assessments and document whether the design, construction, operation, and maintenance of the CCR unit is consistent with recognized and generally accepted good engineering practices for the maximum volume of CCR and CCR wastewater which can be impounded therein. The assessment shall, at a minimum, document whether the CCR unit has been designed, constructed, operated, and maintained with:

(i) Stable foundations and abutments;

(ii) Adequate slope protection to protect against surface erosion, wave action, and adverse effects of sudden drawdown;

(iii) Dikes mechanically compacted to a density sufficient to withstand the range of loading conditions in the CCR unit;

(iv) Vegetated slopes of dikes and surrounding areas except for slopes which have an alternate form or forms of slope protection;

(v) A single spillway or a combination of spillways configured as specified in Subsection R315-319-74(d)(1)(v)(A). The combined capacity of all spillways shall be designed, constructed, operated, and maintained to adequately manage flow during and following the peak discharge from the event specified in Subsection R315-319-74(d)(1)(v)(B).

(A) All spillways shall be either:

(I) Of non-erodible construction and designed to carry sustained flows; or

(II) Earth-or grass-lined and designed to carry short-term, infrequent flows at non-erosive velocities where sustained flows are not expected.

(B) The combined capacity of all spillways shall adequately manage flow during and following the peak discharge from a:

(I) Probable maximum flood (PMF) for a high hazard potential CCR surface impoundment; or

(II) 1000-year flood for a significant hazard potential CCR surface impoundment; or

(III) 100-year flood for a low hazard potential CCR surface impoundment.

(vi) Hydraulic structures underlying the base of the CCR unit or passing through the dike of the CCR unit that maintain structural integrity and are free of significant deterioration, deformation, distortion, bedding deficiencies, sedimentation, and debris which may negatively affect the operation of the hydraulic structure; and

(vii) For CCR units with downstream slopes which can be inundated by the pool of an adjacent water body, such as a river, stream or lake, downstream slopes that maintain structural stability during low pool of the adjacent water body or sudden drawdown of the adjacent water body.

(2) The periodic assessment described in Subsection R315-319-74(d)(1) shall identify any structural stability deficiencies associated with the CCR unit in addition to recommending corrective measures. If a deficiency or a release is identified during the periodic assessment, the owner or operator unit shall remedy the deficiency or release as soon as feasible and prepare documentation detailing the corrective measures taken.

(3) The owner or operator of the CCR unit shall obtain a certification from a qualified professional engineer stating that the initial assessment and each subsequent periodic assessment was conducted in accordance with the requirements of Section R315-319-74.

(e) Periodic safety factor assessments.

(1) The owner or operator shall conduct an initial and periodic safety factor assessments for each CCR unit and document whether the calculated factors of safety for each CCR unit achieve the minimum safety factors specified in Subsections R315-319-74(e)(1)(i) through (v) for the critical cross section of the embankment. The critical cross section is the cross section anticipated to be the most susceptible of all cross sections to structural failure based on appropriate engineering considerations, including loading conditions. The safety factor assessments shall be supported by appropriate engineering calculations.

(i) The calculated static factor of safety under the end-of-construction loading condition shall equal or exceed 1.30. The assessment of this loading condition is only required for the initial safety factor assessment and is not required for subsequent assessments.

(ii) The calculated static factor of safety under the long-term, maximum storage pool loading condition shall equal or exceed 1.50.

(iii) The calculated static factor of safety under the maximum surcharge pool loading condition shall equal or exceed 1.40.

(iv) The calculated seismic factor of safety shall equal or exceed 1.00.

(v) For dikes constructed of soils that have susceptibility to liquefaction, the calculated liquefaction factor of safety shall equal or exceed 1.20.

(2) The owner or operator of the CCR unit shall obtain a certification from a qualified professional engineer stating that the initial assessment and each subsequent periodic assessment specified in Subsection R315-319-74(e)(1) meets the requirements of Section R315-319-74.

(f) Timeframes for periodic assessments

(1) Initial assessments. Except as provided by Subsection R315-319-74(f)(2), the owner or operator of the CCR unit shall complete the initial assessments required by Subsections R315-319-74(a)(2), (d), and (e) prior to the initial receipt of CCR in the unit. The owner or operator has completed an initial assessment when the owner or operator has placed the assessment required by Subsections R315-319-74(a)(2), (d), and (e) in the facility's operating record as required by Subsection R315-319-105(f)(5), (10), and (12).

(2) Frequency for conducting periodic assessments. The owner or operator of the CCR unit shall conduct, complete the assessments required by Subsections R315-319-74(a)(2), (d), and (e) every five years. The date of completing the initial assessment is the basis for establishing the deadline to complete the first subsequent assessment. The owner or operator may complete any required assessment prior to the required deadline provided the owner or operator places the completed assessment(s) into the facility's operating record within a reasonable amount of time. In all cases, the deadline for completing subsequent assessments is based on the date of completing the previous assessment. For purposes of Subsection R315-319-74(f)(2), the owner or operator has completed an assessment when the relevant assessment(s) required by Subsections R315-319-74(a)(2), (d), and (e) has been placed in the facility's operating record as required by Subsection R315-319-105(f)(5), (10), and (12).

(3) Failure to document minimum safety factors during the initial assessment. Until the date an owner or operator of a CCR unit documents that the calculated factors of safety achieve the minimum safety factors specified in Subsections R315-319-74(e)(1)(i) through (v), the owner or operator is prohibited from placing CCR in such unit.

(4) Closure of the CCR unit. An owner or operator of a CCR unit who either fails to complete a timely periodic safety factor assessment or fails to demonstrate minimum safety factors as required by Subsection R315-319-74(e) is subject to the requirements of Subsection R315-319-101(c).

(g) The owner or operator of the CCR unit shall comply with the recordkeeping requirements specified in Subsection R315-319-105(f), the notification requirements specified in Subsection R315-319-106(f), and the internet requirements specified in Subsection R315-319-107(f).

Notes

Utah Admin. Code R315-319-74

Adopted by Utah State Bulletin Number 2016-18, effective 9/1/2016