Title 401 | Chapter 046 | Regulation 130REG
PROPOSED
This document is not yet current.
ENERGY AND ENVIRONMENT CABINET
Department for Environmental Protection
Division of Waste Management
(New Administrative Regulation)
401 KAR 46:130.Groundwater assessment and corrective action for coal combustion residuals (CCR).
Section 1.
Groundwater Assessment, Remedy Selection, and Corrective Action. Except as established in this administrative regulation, the groundwater assessment, selection of remedy, and corrective action requirements for a CCR unit shall be as established in C.F.R. 257.95 through 257.98. The requirements established in 40 C.F.R. 257.96(a) shall be replaced with:(1)
(a)
Within 90 days of finding that any constituent listed in Appendix IV in 40 C.F.R. Part 257 above the maximum contaminant level (MCL) as established in 401 KAR 30:031, or significant level exceeding the groundwater protection standard established in 40 C.F.R. 257.95(h) for parameters that have no MCL, or immediately upon detection of a release from a CCR unit, the owner or operator must initiate an assessment of corrective measures to prevent further releases, to remediate any releases, and to restore affected area to original conditions. The assessment of corrective measures must be completed within 90 days, unless the owner or operator demonstrates the need for additional time to complete the assessment of corrective measures due to site-specific conditions or circumstances.(b)
For parameters that have no MCLs, a significant increase over background shall be determined using a statistical test established in 40 C.F.R. 257.93. If after assessment monitoring, the parameters remain below the standard established in 40 C.F.R. 257.95(h), no other parameter exceeds a groundwater protection standard, and plume stability has been demonstrated pursuant to this regulation, the permittee may resume detection monitoring.(2)
(a)
The assessment of corrective measures, the application of approved corrective measures, including long-term monitoring and maintenance shall be based upon a sitewide conceptual site model performed pursuant to 401 KAR 46:130 which discusses short-term and long-term exposure risks associated with the release and proposed remedies. Short-term risks, including a cost-benefit evaluation of any removal activities, shall consider localized and environmental impacts such as increased road hazards, increased risk of additional releases, and increased emissions.(b)
Monitoring data produced during any assessment monitoring period required by 40 C.F.R. 257.95 shall be incorporated into the conceptual site model (CSM) performed pursuant to 401 KAR 46:130.(3)
The owner or operator must obtain a certification from a qualified professional attesting that the demonstration is accurate.(4)
The 90-day deadline to complete the assessment of corrective measures may be extended for no longer than 60 days.(5)
The owner or operator shall submit the assessment required by this section to the Director of the Division of Waste Management for review and approval.(6)
Upon approval by the cabinet, the owner or operator must also include the demonstration in the annual groundwater monitoring and corrective action report required by 40 C.F.R. 257.90(e).Section 2.
Karst Terrain. Karst terrain requirements shall be as established in 401 KAR 46:110, Section 9.Section 3.
Groundwater Assessment Monitoring.(1)
Except as provided in this section, the requirements for a groundwater assessment monitoring program shall be as established in 40 C.F.R. 257.95(g).(2)
To implement the requirements in 40 C.F.R. 257.95(g)(1), the following procedures are established.(a)
CCR corrective action shall reduce a concentration of Contaminants of Concern (COC) in groundwater to levels below the MCLs established by 401 KAR 8:250, Section 1, ambient background values, or risk-based levels for parameters that lack an MCL.(b)
No later than February 9, 2027, the owner or operator shall submit to the cabinet, CCR Corrective Action Plan. The CCR Groundwater Corrective Action Plan shall include:1.
The methods to be used to abate release of COCs;2.
The methods to be used to prevent further release of COCs;3.
A description of the means used to restore or replace contaminated water supplies;4.
The milestones and total time to complete corrective action as established in subsection (a) of this subsection; and5.
A conceptual site model as established in paragraph (e) of this subsection.(c)
Upon proposed approval of the Corrective Action Plan by the cabinet, a public notice shall be published as established in 401 KAR 46:120, Section 8.(d)
Corrective action measures shall be initiated and completed within the time period required in the permit.(e)
An owner or operator shall submit a CSM.1.
The CSM shall be scientifically and geologically sufficient to understand the release of the COCs and to enable a comprehensive and conceptual understanding of the impacts, impact boundaries, and fate and transport of the uppermost groundwater aquifer, and underlying hydraulically-connected aquifers.2.
The CSM shall also include:a.
The incorporation of all previous and relevant assessment, investigatory, and characterization work, data, and information related to defining the nature and extent of the COC contamination and impact;b.
A concise executive summary of the CSM report findings and recommendations;c.
To the extent known or reasonably obtained, a site description and history;d.
In accordance with C.F.R. § 257.75 and to the extent known or reasonably obtained, a comprehensive, accurate, and complete discussion regarding the identification, regulatory, operational, and investigational history of the site, and a chronology of events related to all CCR units and CCR Areas of Potential Concern (APC), releases, and potential releases. At a minimum, this discussion shall include the elements of C.F.R Part 257.75 (c)(1)(i) through (xiv) and (d)(1)(i) through (xiii).e.
To the extent known or reasonably obtained, a description of the land use status of the site and adjacent properties;f.
A map depicting domestic use well, municipal well or well field, and well head protection area survey within a radius commensurate with the COCs under investigation and their characteristic fate and transport within the specific groundwater regime impacted;g.
A description and analysis of the geologic and hydrogeologic setting relevant to the release;h.
A description, discussion, and analysis of the nature and extent of the mass discharge strength of the source and plume;i.
An assessment of the applicability of the Darcy Flux concept as defined in this administrative regulation or other groundwater velocity and flow concepts, consistent with the specific geologic and hydrogeologic setting;j.
A description, discussion, and analysis of groundwater impacts that references the appropriate maps, figures, tables, and appendices regarding the:(i)
COCs;(ii)
Plume source area;(iii)
Plume migration pathway;(iv)
Existing and potential future points of exposure and extraction points;(v)
Plume terminus; and(vi)
COC groundwater impact trends per monitoring point, along a cross-section of the plume's major axis length in the predominant downgradient direction, and across the plume's minor axis width;k.
A description, discussion, and analysis of the nature and extent of impacted surface and subsurface soil, as applicable;l.
A description, discussion, and analysis of the nature and extent of impacted sediment, as applicable;m.
A description, discussion, and analysis of the nature and extent of impacted surface water(s), as applicable;n.
A description, discussion, and analysis of ecological impacts, as applicable;o.
Conclusions and recommendations;p.
Figures, maps, graphs, and tables, including:(i)
Aerial photographs;(ii)
A site survey map;(iii)
A site map of the source;(iv)
Site maps of historic and recent soil sampling locations and data;(v)
Site maps of historic and existing monitoring wells;(vi)
Site maps of historic and recent monitoring wells and data;(vii)
Site maps of historic and recent groundwater potentiometric surface with flow trend direction indicated;(viii)
Site maps indicating groundwater COCs isoconcentration contours;(ix)
A map of the portion of the 7.5-minute United States Geological Survey (USGS) Topographic Map or a map providing equivalent information depicting the location of the site, name of the map, latitude and longitude labels, and a map scale;(x)
A map of the portion of the 7.5-minute USGS Geologic Quadrangle Map, or a map providing equivalent information depicting the location of the site, the name of the map, latitude and longitude labels, a map scale, and a description of the site geology from the geologic quadrangle;(xi)
Geologic and soil cross sections depicted along the major and minor axes of the contaminant plume indicating the plume source, migration pathway, exposure and extraction points, as applicable, and plume terminus, soil and lithological stratigraphy, hydraulically significant geologic features, average depth groundwater elevation, average depth to plume elevation, and other pertinent subsurface features, including underground utilities and preferred pathways;(xii)
A site bedrock contour map, as applicable;(xiii)
Hydrographs for all monitoring wells and alternative groundwater monitoring points;(xiv)
Concentration versus time plots for each monitoring well and alternative groundwater monitoring points for trend analysis;(xv)
Concentration, as average of mass across monitoring wells and alternative groundwater monitoring points along the primary major and minor axes versus time plots for trend analysis;(xvi)
Groundwater elevation data tables for all historic and existing monitoring wells and alternative groundwater monitoring points, which shall at a minimum, include all relevant current and historic gauging data for each monitoring well and alternative groundwater monitoring points, all relevant monitoring well and alternative groundwater monitoring point's identification designations, groundwater gauging dates, and identification of any abandoned wells;(xvii)
Groundwater analytical data tables for all historic and existing monitoring wells and alternative groundwater monitoring points, which shall at a minimum include all relevant current and historic analytical data for each monitoring well and alternative groundwater monitoring points, all relevant monitoring well and alternative groundwater monitoring point's identification designations, sample collection dates, analytical results, and identification of any abandoned wells;(xviii)
Soil analytical data tables for all soil samples collected, which shall at a minimum include sample identification numbers, depths sampled, sample collection dates, analytical results, and identification of any excavated sampled areas;(xix)
Current photographs of the site and adjacent sites;(xx)
Copies of all boring logs, logged by a geologist; and(xxi)
Copies of all monitoring well records, including records for abandoned monitoring wells;q.
The owner or operator of any facility regulated under this section shall obtain a certification statement, signature, and stamp or seal by a qualified Professional Geologist (PG), stating that the CSM complies with the requirements of this administrative regulation, that all geologic and hydrogeologic data, analysis, and interpretations comply with KRS Chapter 322A and has been performed, designed, utilized, and implemented by a PG or a geologist-in-training under the direct supervision and review of a PG to assess and provide for the protectiveness of public health and welfare and the environment to the fullest extent possible;r.
The owner or operator of any facility regulated under this regulation shall obtain a certification from a qualified Professional Engineer (PE) stating that the clause d. of this subparagraph meets the requirements of C.F.R, Part 257.75;s.
The owner or operator of any facility regulated under this section must provide a notarized, dated, and signed certification that all data, site evaluation, and information provided by the owner or operator to the PE and PG consultant, and contained in the PE and PG certified CSM, to the best of their knowledge and understanding, is true, accurate, and complete, with the following statement signed by the owner or operator or an authorized representative: "I certify under penalty of law that I have personally examined and am familiar with the information submitted in this demonstration and all attached documents, and that, based on my inquiry of those individuals immediately responsible for obtaining the information, I believe that the submitted information is true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment.";t.
The Groundwater CCR Plume Geochemical Study and Analysis (GSA) Demonstration established in Section 4 shall be submitted as an appendix to the CSM.(f)
1.
For CCR facilities subject to this administrative regulation, the requirements established in 40 C.F.R. 257.90(e) for the groundwater monitoring and corrective action report shall be replaced with the requirement for the owner or operator to submit an annual CCR Corrective Action Update no later than January 31.2.
The CCR Groundwater Corrective Action Update shall include:a.
Any updated information relevant to the requirements in the CSM; andb.
The requirements established by 40 C.F.R. 257.90(e).Section 4.
Groundwater Coal Combustion Residuals (CCR) Plume Geochemical Study and Analysis (GSA) Demonstration.(1)
The party or applicant shall perform and submit a GSA Demonstration Report of the CCR groundwater plume's geochemical conditions and state.(2)
A GSA Demonstration Report is a documented study and analysis performed to demonstrate the geochemical conditions and state of the CCR groundwater plume. The GSA Demonstration Report is an evaluation of geochemical plume conditions and external parameters that may limit or promote the stability or instability of metals mobilization within the groundwater aquifer.(3)
The GSA Demonstration Report general provisions and core requirements shall address and at a minimum include the following scientific, geologic, and technical criteria:(a)
Data, analysis, and presentations of the plume status in space (lateral and vertical communication) and time;1.
Expansion;2.
Steady-state; or3.
Decay.(b)
Data, analysis, and presentations of the geochemical plume status, geochemical parameters and conditions that limit or promote stability or instability for metals mobilization in the groundwater aquifer:1.
pH conditions;2.
Redox conditions;3.
Soil sorption capacity conditions; and4.
Mineral equilibrium conditions.(c)
Data, analysis, and presentations of plume mass discharge rate (Md);(d)
Data, analysis, assessment, and presentations of existing, future likely, and future potential groundwater extraction points mass extraction rate (Me) of existing and future potential and likely groundwater extraction point receptors;(e)
Data, analysis, and designation of plume magnitude;(4)
The GSA Demonstration Report prepared and submitted for agency review and approval to support a geochemical stability determination shall, at a minimum, include the following technical elements, supporting data, analytical evaluations, and performance metrics necessary to demonstrate and document the geochemical study:(a)
A concise executive summary of the GSA Demonstration Report's findings, conclusions, and recommendations.(b)
An evaluation of Plume Status in Space and Time, including supporting data, statistical analyses, hydrogeologic interpretation, and technical discussion addressing the following:1.
Statistically significant concentration trends for Appendix IV and other applicable COCs at plume boundary monitoring wells,2.
Testing, data evaluation, and analysis of downgradient groundwater conditions relative to plume expansion, steady-state behavior, or attenuation decay for Appendix IV and other applicable COCs beyond the historical plume footprint,3.
Testing, data and analysis downgradient of the groundwater plume historical footprint, including:a.
In relation to existing groundwater extraction points inducing and influencing the groundwater gradient related to the groundwater CCR plume, andb.
In relation to applicable likely future and potential future Groundwater Extraction Point(s) inducing and influencing related to the groundwater gradient on the groundwater CCR plume.4.
Characterization of upgradient natural background groundwater conditions outside areas exhibiting plume expansion, steady-state conditions, or attenuation for Appendix IV and other applicable COCs relative to the historical plume footprint; and5.
Demonstration and evaluation of groundwater mass flux and mass discharge for Appendix IV and other applicable COCs to determine whether the groundwater plume is expanding, stable, or decreasing.(c)
An evaluation of geochemical plume conditions and external parameters that may limit or promote the stability or instability of metals mobilization within the groundwater aquifer.(d)
The geochemical evaluation shall include supporting data, testing results, analyses, geochemical interpretation, and technical discussion addressing the following:1.
Identification and evaluation of geochemical conditions demonstrating whether site-specific conditions facilitate, limit, or arrest the mobility of Appendix IV metals and other applicable COCs;2.
Evaluation of whether the mobility or immobility of Appendix IV and other applicable COCs is spatially and temporally stable and persistent on a seasonal and annual basis, or whether such conditions are temporally or spatially variable, uncertain, or demonstrably unstable; and3.
Geochemical testing, data evaluation, analysis, and interpretation including, at a minimum:a.
Identification of the primary source type, including the anthropogenic source matrix and relevant aquifer matrix materials;b.
Seasonal and annual testing, analysis, and evaluation of oxidation–reduction (redox) conditions and trends associated with stability or instability of Appendix IV and other applicable COCs;c.
Seasonal and annual testing, analysis, and evaluation of aerobic and anaerobic redox conditions within the subject aquifer groundwater and their relationship to Appendix IV and other applicable COCs;d.
Seasonal and annual testing, analysis, and evaluation of pH stability, variability, or instability within the subject aquifer groundwater in relation to Appendix IV and other applicable COCs;e.
Testing and analysis of pH conditions, including acidic, neutral, or alkaline conditions, within the subject aquifer groundwater and their relevance to Appendix IV and other applicable COCs;f.
Testing and analysis of soil and aquifer material sorption capacity, including pedololithic soils, anthropogenic fill materials, and aquifer matrix materials, evaluated both laterally and vertically;g.
Demonstration of whether geochemical factors associated with the CCR source are expanding laterally or downgradient within the aquifer system; andh.
Testing, analysis, and modeling evaluating geochemical mineral equilibrium conditions associated with the CCR source and the groundwater aquifer.4.
Geochemical source and groundwater conditions shall be demonstrated and evaluate geochemical conditions at a site utilizing:a.
The most recent published version of the United States Geologic Survey's (USGS) Ph, Redox Equilibrium (PHREEQC) model as the minimal acceptable means; orb.
The Registered Professional Geologist (PG) responsible for the applicable certifications may propose another scientifically valid method, model, or combination of methods. Use of an alternative approach shall be supported by sufficient technical documentation demonstrating to the satisfaction of the cabinet that the proposed approach:(i)
Is demonstrated to serve the same technical purpose as the USGS PHREEQC model for the specific geochemical evaluation being performed;(ii)
Is demonstrated to provide capabilities that are equivalent to or technically superior to those of the USGS PHREEQC model for the specific site conditions and evaluation objectives; andc.
The above demonstrations have been technically reviewed and approved by a cabinet Registered Professional Geologist (PG) prior to its use as the basis for the applicable GSA Demonstration Report certification.5.
Analysis and demonstration of whether the first aquifer immediately beneath the upper impacted aquifer is in communication with the upper impacted aquifer, or is impacted by Appendix IV and other applicable COCs spatially, seasonally, or annually from the impacted upper aquifer.(e)
Groundwater Plume Geochemical Spatial Status (Plume Footprint). In order to demonstrate the lateral and downgradient spatial status of the groundwater plume spatial maps and figures to scale shall be prepared and submitted isoconcentration (plane view) time-sequenced plume maps for each Indicator constituent, Appendix IV metal, and other identified applicable COCs using and showing 3 to 5 representative seasonal wet period and dry period events, over 2 to 4 years. Isoconcentration time-sequenced maps shall include at a minimum:1.
Consistent contour intervals;2.
The primary source area;3.
The plume core;4.
The plume's boundaries; background bounds, leading edge, and side lateral bounds;5.
Overlays of the dominant seasonal and annual groundwater flow direction;6.
The location of all sentinel and monitoring wells;7.
The location of all existing groundwater extraction points; and8.
Standard mapping components, which shall include:a.
Map title;b.
Compass rose or north arrow;c.
Map legend or key;d.
Inset map;e.
Locator map;f.
Map scale;g.
Data frame;h.
Source; andi.
Professional Geologist (P.G.) Stamp.(f)
Groundwater Plume Geochemical Vertical Status (Cross-Sections). In order to demonstrate the vertical and hydrogeologic vertical communication status of the groundwater plume vertical geologic and groundwater cross-section with scaled vertical exaggeration shall be prepared and submitted.1.
Prepare hydrostratigraphic vertical concentration indicated plume cross sections for each Indicator constituent, Appendix IV metal, and other identified applicable COCs.2.
Hydrostratigraphic vertical concentration indicated plume cross sections shall include:a.
Well/boring identification;b.
Well/boring map location inset;c.
Vertical and horizontal scales;d.
Electrical logs;e.
Screened intervals;f.
Geologic data;g.
Soil type;h.
Stratigraphy;i.
Geologic features;j.
Age of geologic units;k.
Stratigraphic correlations;l.
Static groundwater level;m.
Metals concentrations by depth; andn.
Professional Geologist (P.G.) Stamp.(g)
Groundwater Plume Geochemical Temporal Status (Trend Analysis). In order to demonstrate the temporal status of the groundwater plume trend, analysis for Appendix IV and other applicable COCs shall be prepared and submitted.1.
Temporal stability trend analysis shall use;a.
Mann-Kendall non-parametric statistical determination method test to analyze if trends over time are present. Mann-Kendall determines if the COC trends are increasing, decreasing, stable;b.
Sen's Slope non-parametric statistical tests to quantify the strength and rate of change over time of an identified trend. Sen's Slope supports corrective action decisions and risk analysis;c.
Other appropriate statistical method for groundwater analysis listed in 401 KAR 48:300, Section 9 or U.S. EPA's Groundwater Statistics Tool; ord.
Other appropriate and applicable statistical methods for groundwater analysis upon approval by the cabinet in the context of a specific report if use of the alternative statistical approach is supported by sufficient technical documentation demonstrating to the satisfaction of the cabinet that the proposed approach:(i)
Is demonstrated to serve the same technical purpose as the statistical model, Mann-Kendall or Sen's Slope, for the specific geochemical evaluation being performed;(ii)
Is demonstrated to provide capabilities that are equivalent to or technically superior to those of the Mann-Kendall or Sen's Slope for the specific site conditions and evaluation objectives; and(iii)
The demonstration has been technically reviewed and approved by a cabinet Registered Professional Geologist (PG) prior to its use as the basis for the applicable GSA Demonstration Report certification.2.
Mann-Kendall and Sen's Slope non-parametric statistical tests shall be applied to:a.
Unit boundary wells;b.
Plume boundary wells (up, down, and side gradient);c.
Sentinel wells;d.
Monitoring wells; ande.
Highest concentration plume core wells.3.
Temporal stability trends shall be classified as:a.
Increasing;b.
Decreasing; andc.
No trend (stable).4.
Time-series plots demonstrating concentrations over time shall include:a.
Concentration versus time for each COC for each well;b.
Overlay of applicable regulatory standards; andc.
Highlight of long-term trends.(h)
Groundwater Plume Mass Discharge Rate Estimates, Analysis, and Demonstration. In order to demonstrate groundwater plume mass discharge status, the plume shall be evaluated system-wide in both space and time to assess plume stability, rather than relying solely on discrete point measurements. The evaluation shall include supporting data, calculations, analysis, and technical interpretation sufficient to characterize plume loading conditions. Plume mass discharge demonstrations shall include, at a minimum, the following:1.
An estimate of the mass discharge rate at the groundwater plume terminus for all CCR Appendix IV COCs and other applicable COCs that exceed applicable regulatory or risk-based levels.2.
An estimate of the mass discharge rate at the groundwater plume terminus for all CCR Appendix IV and other applicable COCs exceeding their applicable regulatory levels, compared to an estimated mass extraction rate for all existing, likely future, and potential future groundwater extraction points using a baseline concentration of 0.002 parts per million (ppm) (mg/L), corresponding to the MCL for mercury (Hg).3.
An estimate of the daily mass discharge rate at the groundwater plume terminus for all CCR Appendix IV and other applicable COCs exceeding applicable regulatory levels, compared to the estimated daily mass extraction rates for all existing and reasonably foreseeable future groundwater extraction points calculated for each applicable regulatory level. This comparison shall determine whether the daily mass discharge rates at the plume terminus for each CCR Appendix IV and other applicable COC exceedance are greater than, equal to, or less than the estimated daily mass extraction rates for applicable existing, likely future, and potential future groundwater extraction points.(i)
In order to assess the groundwater plume mass discharge and groundwater extraction point mass extraction rates, the owner or operator shall determine:1.
The groundwater plume mass discharge rate (Md) at the plume terminus; and2.
The mass extraction rate (Me) at all applicable:a.
Existing groundwater extraction points;b.
Likely future groundwater extraction points; andc.
Potential future groundwater extraction points.(j)
Methodology.1.
The calculation of mass discharge (Md) and mass extraction (Me) may utilize the standard data tables identified as Tables 1 through 3 of this administrative regulation below:| Table 1. Kentucky Rivers Average Flow Rates as a Groundwater Extraction Point. | |||
| Kentucky River | Flow Rate(Cu.Ft./Sec.) | Flow Rate(Gal./Sec.) | Flow Rate(Gal./da.) |
| Beargrass Creek | 103 | 770 | 66,570,640 |
| Elkhorn Creek | 677 | 5,064 | 437,556,534 |
| Tradewater River | 1,070 | 8,004 | 691,559,072 |
| North Fork Kentucky River | 1,099 | 8,221 | 710,302,262 |
| Salt River | 1,704 | 12,747 | 1,101,323,980 |
| Barren River | 2,501 | 18,709 | 1,616,438,541 |
| Big Sandy River | 5,007 | 37,455 | 3,236,108,667 |
| Licking River | 5,694 | 42,594 | 3,680,128,370 |
| South Fork Licking River | 275 | 2,057 | 177,737,145 |
| Kentucky River | 8,924 | 66,756 | 5,767,731,924 |
| Green River | 14,574 | 109,021 | 9,419,422,350 |
| Cumberland River | 37,250 | 278,649 | 24,075,304,141 |
| Tennessee River | 70,575 | 527,938 | 45,613,814,490 |
| Ohio | 281,500 | 2,105,766 | 181,938,204,450 |
| Ohio-Mississippi at Confluence | 593,000 | 4,435,948 | 383,265,915,591 |
| Table 2. Stream and River Classification Average Flow Rates | ||||
| *Stream River Flow Class | Base FlowCubic Feet per Second (cfs) | Base FlowGallons per Day (gpd) | Kentucky Rivers and Streams Examples | Notes |
| Very Small Stream Headwaters | <1 | <646,000 | Unnamed headwater tributaries to Red River (eastern Kentucky uplands). Small tributaries to Elkhorn Creek in Fayette/Scott counties. | **1st Order Stream. |
| Small Streams | 1–100 | 0.65–64.6 million | Upper Floyd's Fork, Elkhorn Crk., Upper tributaries to Licking River. | **2nd and 3rd Order Streams. |
| Medium Rivers | 100–10,000 | 64.6 million–6.46 billion | Salt, Big Sandy, Licking, Barren, and Kentucky Rivers. | **4th, 5th, and 6th Order Rivers. |
| Large Rivers | 10,000–100,000 | 6.46–64.6 billion | Green, Cumberland, and Tennessee Rivers. | **7th and 8th Order Rivers. |
| Major Continental Rivers | >100,000 | >64.6 billion | Ohio and Mississippi Rivers. | **8th Order Rivers. |
| References: *Based on Leopold, L, Wolman, M.G., Miller, J.P. Fluvial Process in Geomorphology. (1964). **Based on Strahler Stream Order (1952). | ||||
| Table 3. Spring Classification Average Flow Rates | ||||
| *Stream/River Magnitude Order | DischargeCubic Feet per Second (cfs) | DischargeGallons per Day (gpd) | Kentucky Spring and Seep Examples | Notes |
| 8th (Small Seep, Minor Spring) | <0.0003 cfs | <180 | Minor hillside discharges, E. Kentucky Coal Field fractured sandstones & shales, Upland residual soils over limestone. | Often seasonal; common in shallow perched systems. |
| 7th (Small Seep, Minor Spring) | 0.0003–0.002 cfs | 180–1,440 | Minor hillside discharges, E. Kentucky Coal Field fractured sandstones & shales, Upland residual soils over limestone. | Often seasonal; common in shallow perched systems. |
| 6th (Small Spring) | 0.002–0.02 cfs | 1,440–14,400 | Farmstead springs, Spring box domestic supplies, Hillside seeps feeding small tributaries. | Typical rural domestic supply range. |
| 5th (Small Spring) | 0.02–0.22 cfs | 14,400–144,000 | Farmstead springs, Spring box domestic supplies, Hillside seeps feeding small tributaries. | Typical rural domestic supply range. |
| 4th (Moderate Spring) | 0.22–1 cfs | 144,000–646,000 | Common in central Kentucky karst belt. Captured for rural water supply or forming small perennial headwaters. | Capable of forming a perennial stream channel. |
| 3rd (Large Spring) | 1–10 cfs | 0.65–6.46 million | Shaker, Elizabethtown. | Equivalent to a small stream baseflow. |
| 2nd (Large Spring) | 10–100 cfs | 6.46–64.6 million | Crab Orchard, Lulbegrud Crk. Sp., Booneville. | Equivalent to a small stream baseflow. |
| 1st (Regional Spring) | ≥100 cfs | ≥64.6 million | Mammoth Spring, Big Spring. | Regionally significant groundwater discharge points. |
| References: *Based on USGS Meinzer (1927) | ||||
2.
Tables 1 through 3 shall provide default or representative parameter values for groundwater flow, extraction rates, and receptor classifications where site-specific data is unavailable or insufficient.3.
Where site-specific hydrogeologic data is available, the owner or operator may use measured values in lieu of default tabulated values, unless otherwise approved by the cabinet.(k)
The calculated Md at the plume terminus and Me at all existing and applicable speculative groundwater extraction points shall be used to:1.
Classify groundwater plume magnitude;2.
Assess the plume magnitude in relation to groundwater extraction point at risk receptors and potential receptors;3.
Assess and record plume magnitude strength and status;4.
Evaluate receptor impact potential;5.
Support corrective action determinations; and6.
Evaluate and support short- and long-term risk analysis, evaluation of risk and potential risk, risk management, and institutional, engineering, and natural controls.(l)
Groundwater plume magnitude classification shall be determined based on the calculated mass discharge rate of the plume. The classification shall be derived using the mass discharge rate corresponding to the lowest applicable MCL exceedance for Appendix IV constituents or other applicable COCs, or the lowest applicable risk-based concentration level where an MCL is not available.1.
The mass discharge rate shall be expressed in grams per day (g/day).2.
Groundwater plume magnitude classification shall be classified according to the total calculated mass discharge (Md) at the plume terminus in accordance with Table 4 of this administrative regulation below:| Table 4. Groundwater Plume Magnitude Strength (5 Major Categories) | ||
| Plume Magnitude Category | Md – Mass Discharge Range (g/day) | First Plume Magnitude Impacting > Regulatory or Risk Exceedance Level at a Groundwater Extraction Point (Receptor) |
| I – De Minimis / Trace | < 0.01 | Consumptive Wells: Average domestic use well (~150 gal/day). |
| Streams/Rivers: Typically limited to ephemeral drainage or diffuse headwater seepage. | ||
| Springs: 8th–7th order minor seeps and hillside discharges (Eastern Kentucky coal field fractured sandstones & shales; upland residual soils over limestone). | ||
| II – Minor / Localized | 0.01 – 1 | Consumptive Wells: Small domestic or farmstead wells. |
| Streams/Rivers: Very small 1st order headwater streams (e.g., unnamed tributaries to the Red River; small tributaries to Elkhorn Creek in Fayette/Scott Counties). | ||
| Springs: 6th–5th order small springs (farmstead springs, spring box domestic supplies, hillside seeps feeding small tributaries). | ||
| III – Moderate / Developing | 1 – 100 | Consumptive Wells: Public supply or agricultural wells (≥100 gallons per minute). |
| Streams/Rivers: Small 2nd–3rd order streams (Upper Floyd's Fork; Elkhorn Creek; upper tributaries to Licking River; Beargrass Creek). | ||
| Springs: 4th–3rd order springs (moderate to large springs common in central Kentucky karst belt; e.g., Shaker Spring – Elizabethtown). | ||
| IV – Major / Regional | 100 – 10,000 | Consumptive Wells: High-capacity municipal or regional supply wells. |
| Streams/Rivers: Medium 4th–6th order rivers (Salt, Big Sandy, Licking, Barren, Kentucky Rivers). | ||
| Springs: 2nd–1st order large to regional springs (Crab Orchard Spring; Lulbegrud Creek Spring; Booneville Spring; Mammoth Spring; Big Spring). | ||
| V – Severe / Basin-Scale | > 10,000 | Consumptive Wells: Regional groundwater production fields. |
| Streams/Rivers: Large 7th–8th order rivers to continental-scale systems (Tennessee, Cumberland, Green Rivers; Mississippi and Ohio Rivers). | ||
| Springs: Regional karst systems with multi-mile conduit flow and basin-scale discharge influence. | ||
| Note: Groundwater Extraction Point Examples Calculated Regulatory Extraction Exceedance Rates are based on MCL of 0.002 ppm for mercury (Hg). | ||
3.
The determined groundwater plume magnitude shall be evaluated relative to all applicable groundwater extraction points located at, downgradient of, and side-gradient to the site and all evaluated applicable likely and potential future groundwater extraction points.4.
The groundwater plume calculated mass discharge rate shall be evaluated relative to all applicable existing groundwater extraction points mass extraction rates located at, downgradient of, and side-gradient to the site, and all evaluated applicable likely and potential future groundwater extraction points.(5)
Weight-of-Evidence Groundwater Plume Stability Evaluation.(a)
The demonstration of groundwater plume stability for the evaluation of risk and protection of human health and the environment for CCR units and areas of interest Appendix IV metals, and other applicable COCs, require the evaluation of multiple independent lines of evidence that collectively assess whether the plume has reached a stable configuration in space and time.(b)
Dissolved metals mobility or immobility, and consequential present or future risk(s), are primarily influenced by geochemical conditions and hydrogeologic factors. Plume stability cannot be determined solely based on individual concentration measurements at discrete wells or sampling events, nor are such decisions based on concentrations alone scientific, scientifically sound, robust, or legally defensible.(c)
Accordingly, the evaluation of plume stability shall be conducted using a weight-of-evidence framework that integrates spatial plume behavior, temporal concentration trends, plume mass and mass flux characteristics, geochemical controls on metals mobility, and potential receptor impacts.(d)
This approach is consistent with widely accepted regulatory practices applied under groundwater corrective action programs, including those explicitly stated and implemented under 40 C.F.R. Part 257 (Coal Combustion Residuals), RCRA corrective action programs, and CERCLA remedial investigations.(e)
For purposes of this regulation and its gathered information, data, evaluation, and analysis: A stable groundwater plume is defined as a plume that demonstrates the following conditions:1.
No statistically significant increasing trends in concentrations at downgradient plume boundary wells or sentinel monitoring wells;2.
No lateral or downgradient expansion of the plume footprint relative to historical monitoring data;3.
Stable or declining dissolved plume mass or mass discharge; and4.
Persistent geochemical conditions that limit metals mobility through processes such as sorption, precipitation, or co-precipitation.(f)
Evaluation of plume stability based on the scientific and technical requirements of this section shall include and yield, at a minimum, the following lines of evidence:1.
Spatial stability, demonstrated through consistent plume geometry and absence of lateral or downgradient expansion based on isoconcentration mapping and hydrostratigraphic cross sections;2.
Temporal stability, demonstrated through statistical trend analysis (e.g., Mann-Kendall or Sen's slope) and long-term time-series evaluation of COC concentrations;3.
System-scale plume behavior, demonstrated through estimates of dissolved plume mass and, where practicable, mass flux or mass discharge across downgradient transects;4.
Geochemical stability, demonstrated through evaluation of groundwater chemistry parameters that influence metals mobility and through geochemical modeling or speciation analysis where appropriate;5.
Source term conditions, including evaluation of whether the source area is controlled, removed, capped, or otherwise stabilized; and6.
Receptor protection, including confirmation that the plume remains contained on-site and does not pose a current or reasonably foreseeable future risk to downgradient receptors.(g)
The results of these evaluations are summarized for simplicity and to assist regulatory decision in the following tables:1.
Table 5. CCR Groundwater Metals Plume Stability – Decision Matrix. This decision matrix integrates multiple lines of evidence to evaluate groundwater plume behavior for metal COCs associated with coal combustion residuals (CCR) units. The matrix provides a structured, weight-of-evidence framework that considers spatial plume stability, temporal concentration trends, plume mass and mass flux, geochemical controls on metals mobility, source term conditions, and potential receptor impacts. Collectively, these factors are evaluated to support a comprehensive assessment of plume stability and to provide a transparent and regulator-defensible basis for determining plume status and the justification and effectiveness of corrective action and risk management measures; and2.
Table 6. CCR Geochemical Regulatory Decision Outcome. This table provides a structured, regulatory defensible framework for classifying the groundwater plume based on geochemical and hydrogeologic evaluation of metals COCs. Using the weight-of-evidence approach described in Table 5, the plume is assessed across multiple lines of evidence, including spatial stability, temporal trends, plume mass and mass flux, geochemical conditions, source term control, and receptor risk to assign a final classification of Unstable, Conditionally Stable, or Stable. This decision framework ensures a transparent, consistent, and scientifically justified determination regarding CCR groundwater plume behavior and the effectiveness of corrective action and risk management measures.| Table 5. CCR Groundwater Metals Plume Stability – Decision Matrix | ||||
| Line of Evidence | Unstable Condition | Conditionally Stable | Stable Condition | Decision Rule / Notes |
| Plume Footprint (Plan View) | Downgradient or lateral expansion beyond historical footprint | Minor footprint variability without sustained expansion | No expansion; consistent plume geometry across events | Use consistent contour levels; evaluate ≥3–5 multi wet/dry-year 2+ events. |
| Vertical Migration | Downward migration into deeper hydrostratigraphic units | Vertical variability within same unit | Vertically constrained within defined unit | Requires cross-sections with geology and hydrogeology showing screen intervals. |
| Boundary Well Trends | Statistically significant increasing trends | Mixed trends or no trend with short record | No increasing trends (no trend or decreasing) | Mann-Kendall and Sen's slope. |
| Sentinel Well Trends | Increasing trends | No trend with limited data | No increasing trends | Sentinel wells are high-weight evidence. |
| Plume Core Trends | Increasing trends at high-concentration wells | Mixed or stable trends | Stable or decreasing trends | Core trends support mass stability. |
| Time-Series Concentrations | Sustained increases over time | Short-term variability | Stable or declining long-term patterns | Focus on long-term signal vs noise. |
| Plume Mass | Increasing dissolved mass | Approximately stable mass | Stable or declining mass | System-scale metric; high weight evidence metric. |
| Mass Discharge | Increasing downgradient mass flux | Stable with variability | Stable or declining mass flux | Especially useful where concentrations fluctuate point to point. |
| Plume Magnitude Strength 1(See Table 4) | Groundwater plume mass discharge rate (grams/day) exceeds the applicable regulatory or applicable risk-based level, expressed as a mass extraction rate (grams/day), relative to existing or potential future groundwater extraction points. | Groundwater plume mass discharge rate (grams/day) is less than or comparable to applicable regulatory and applicable risk-based levels, expressed as a mass extraction rate (grams/day), relative to existing and likely future groundwater extraction points. | Groundwater plume mass discharge rate (grams/day) is less than applicable regulatory and applicable risk level(s) calculated as a mass extraction rate in (grams/day) relative to existing likely, and potential future groundwater extraction points. | Compares plume magnitude for Appendix IV and other applicable COCs calculated mass discharge rate (grams/day) to the regulatory-level mass extraction rate (grams/day) of existing and reasonably foreseeable downgradient groundwater extraction points. This comparison considers whether plume loading is greater than or less than applicable standards at the point of extraction, and incorporates the probability of future groundwater extraction points (e.g., domestic, public water supply, or agricultural wells) occurring within the defined planning horizon (see Table 4). |
| Plume Magnitude Strength 2(See Tables 1, 2, 3 and 4) | Site groundwater plume magnitude is sufficient, greater than, to impact existing surface water, spring, and seep surface expressed drainage features characteristic of the surrounding geography. | Site groundwater plume magnitude sufficiency is varying (+/-) within one order of magnitude, with respect to potential impacts on existing surface water, spring, and seep surface expressed drainage features typical of the surrounding geography. | Site location groundwater plume magnitude is insufficient, by one magnitude or greater, to impact existing surface water, spring, and seep surface expressed drainage features typical to the geography surrounding the site. | Compares groundwater plume mass discharge (g/day) to surrounding groundwater extraction points and drainage features classifications (streams, rivers, seeps, springs) by converting annual average flow rates (gpd) to equivalent mass extraction/loading rates (g/day) using applicable COC MCLs and risk-based concentrations to evaluate relative magnitude and receptor impact. (See Tables 1, 2, 3 and 4). |
| Geochemical Conditions | Shifting toward mobilizing conditions | Mixed or transitional conditions | Persistent immobilizing conditions | pH, redox, alkalinity, sulfate/sulfide, Fe/Mn. |
| Speciation / Solubility | Undersaturated; high mobility potential | Near equilibrium | At or near solubility limits | PHREEQC USGS or equivalent modeling. |
| Attenuation Mechanisms | No identified attenuation processes | Limited or uncertain attenuation | Documented sorption/precipitation/co-precipitation | Metals-specific line of evidence. |
| Source Term | Active or uncontrolled source | Source partially controlled | Source controlled or declining | Stability claims not demonstrable without source control. |
| Receptor / Compliance Risk | Active or imminent off-site impact | On-site only; future risk uncertain | On-site contained; no current or future risk | Includes surface water, domestic use wells, public supply wells, and agricultural use wells. |
| Table 6. CCR Geochemical Regulatory Decision Outcome | ||
| Overall Weight-of-Evidence Result | Interpretation | Regulatory Action |
| Unstable | Multiple and majority lines of evidence or the most significant indicators, demonstrate plume expansion, increasing concentration trends, or conditions favoring contaminant mobilization. | Continued corrective action required. |
| Conditionally Stable | Mixed results; no clear expansion or stabilization, due to mixed results, data gaps, or uncertainty. | Continued additional monitoring or greater focused evaluation. |
| Stable | All multiple and critical lines of evidence indicate no expansion and stable/declining conditions and concentrations. | Plume stability demonstrated, No Further Action. |
(6)
The owner or operator of any facility regulated under this section shall obtain a certification statement, signature, and stamp or seal by a qualified Professional Geologist (PG), stating that the Groundwater Coal Combustion Residuals (CCR) Plume Geochemical Study and Analysis (GSA) and report complies with the requirements of this administrative regulation, that all geologic and hydrogeologic data, analysis, and interpretations comply with KRS Chapter 322A and has been performed, designed, utilized, and implemented by a PG or a geologist-in-training under the direct supervision and review of a PG to assess and provide for the protectiveness of public health and welfare and the environment to the fullest extent possible.Section 5.
Assessment, Corrective Action, and Remedy Selection.(1)
Except as established in this section, the assessment of corrective measures, corrective action, and remedy selection shall be established in 40 C.F.R. 257.96 through 257.98.(2)
The requirements in 40 C.F.R. 257.96(e) shall be replaced with the requirement for the owner or operator to publish the approved assessment of corrective measures for notice and comment pursuant to 401 KAR 46:120, Section 8.(3)
To implement the requirements in 40 C.F.R 257.96 through 257.98, the following procedures are established.(a)
The CCR groundwater corrective action plan shall be supported by the CSM. If additional data has been obtained following submittal of the CSM, the CCR groundwater corrective action plan shall include the additional data as necessary.(b)
The groundwater corrective action plan shall include a certification statement, signature, and stamp or seal by a PE or PG that the groundwater corrective action plan was prepared to address the requirements of this administrative regulation.(c)
The responsible party shall propose one (1) of the following groundwater remedy selections in the CCR Groundwater Corrective Action Plan:1.
No action necessary in accordance with KRS 224.1-400(18)(a) if the party or applicant submits to the cabinet:a.
A CSM that complies with this administrative regulation, and supports the demonstration that no further action is necessary; andb.
A demonstration that constituents do not exceed:(i)
Target risk levels for unrestricted groundwater use for MCLs established by 401 KAR 8:250, Section 1;(ii)
Ambient background values where ambient background levels are greater than MCLs; and(iii)
Risk-based levels for constituents that lack an MCL;2.
Management in place in accordance with KRS 224.1-400(18)(b) if the responsible party or applicant submits to the cabinet:a.
A revised CSM, as necessary, that complies with 401 KAR 46:130; andb.
A CSM that supports the demonstration that management in place is, and will remain, protective of human health and the environment in perpetuity;3.
Restoration in accordance with KRS 224.1-400(18)(c), which shall apply to sites where the responsible party restores the environment through removal of COCs to below MCLs established by 401 KAR 8:250, Section 1, ambient background values, or risk-based levels for parameters that lack an MCL through source removal, source treatment, or active groundwater remediation; or4.
A combination of options established in subparagraphs 2. and 3. of this paragraph.(d)
The cabinet shall review and approve, disapprove, or notify the applicant of any deficiencies of the groundwater corrective action plan pursuant to this administrative regulation.Section 6.
CCR Groundwater Management in Place Remedy. If the responsible party proposes management in place as the groundwater remedy selection the responsible party shall comply with this section.(1)
A groundwater management in place demonstration shall be submitted to the cabinet for a groundwater management in place remedy selection that shall include:(a)
1.
The removal, reduction, or stabilization of the contamination source to the extent practicable; or2.
A demonstration that the residual contaminant source has been reduced, removed, or stabilized through previous actions or attenuation;(b)
The implementation of sustainable measures that ensure protectiveness to human health and the environment for the duration of the groundwater impact;(c)
The assessment of on- and off-site risk due to the groundwater impact's fate and transport future extents, with present and area specific future potential groundwater users and extraction points;(d)
The consideration of current and proposed or potential future land use in selecting the remedy;(e)
A plan to perform a five-year review and report to the cabinet to ensure stable and protective conditions remain in place;(f)
A demonstration of protectiveness for both current and future exposures at a potential groundwater extraction point that includes a description of the method for maintenance of engineering and institutional controls, including:1.
Annual, or other approved frequency, assessments and inspections of the engineering and institutional controls, as approved by the cabinet in the groundwater corrective action plan;2.
Annual, or other approved frequency, certification to the cabinet by the party or applicant, and a PE or PG, that the engineering and institutional controls remain protective of human health, safety, and the environment; and3.
An environmental covenant in accordance with KRS 224 Subchapter 80 as appropriate;(g)
The CCR groundwater corrective action plan shall:1.
Reduce or stabilize the plume's mass discharge below the applicable MCLs established by 401 KAR 8:250, Section 1, ambient background values, or risk-based levels for parameters that lack MCLs at the present or future potential groundwater points of extraction;2.
Permanently place the groundwater plume into a plume decay or plume steady state;3.
Prevent or control the source or plume from extending the impact further vertically or horizontally toward current or future off-site groundwater extraction points; and4.
Assess, control, or eliminate unacceptable soil vapor intrusion risk exposures as applicable to the COCs and their fate and transport.(2)
If management in place is selected as a corrective action remedy for groundwater contamination, groundwater monitoring shall be required by the cabinet. Groundwater monitoring frequency shall be based upon relevant site-specific geologic, hydrogeologic, and exposure conditions.(3)
The groundwater corrective action plan and most current version of the CSM shall include a certification statement, signature, and stamp or seal by a PE or PG, that the corrective action plan and most current version of the CSM complies with the requirements established in this administrative regulation and is protective of human health and the environment.Section 7.
CCR Groundwater Corrective Action Completion Report.(1)
The party or applicant shall submit a CCR Groundwater Corrective Action Completion Report to the cabinet which shall include:(a)
Documentation that the groundwater corrective actions were implemented, completed, and comply with the CCR Groundwater Corrective Action Plan established in Section 4 that was approved by the cabinet, and consists of;1.
Documentation of any modification from the approved CCR Groundwater Corrective Action Plan;2.
Documentation of the weight, volume, and classification of any material removed as part of the groundwater corrective action;3.
Copies of signed manifests and any other pertinent waste disposal forms;4.
Sampling procedures used for waste profile determination and restoration confirmation;5.
Sampling procedures and methods used for soil, sediment, surface water, groundwater;6.
Results from any confirmatory sampling and copies of all laboratory analytical reports; and7.
Information regarding backfill material, including where it was obtained, and any attendant analytical results;(b)
Documentation of all engineering and institutional controls implemented to contain the release, eliminate pathways of exposure, reduce exposure, or achieve a combination thereof; and(c)
A statement signed by the party or applicant certifying that the document and all attachments were prepared under the direction or supervision of the party or applicant, and the information submitted is, to the best knowledge of the party or applicant, true, accurate, and complete.(2)
(a)
The party or applicant shall revise the CSM submitted pursuant to Section 3 to reflect the groundwater corrective actions implemented and completed with revised data and information, and submit with the CCR Groundwater Corrective Action Completion Report to the cabinet.(b)
The CCR Groundwater Corrective Action Completion Report and most current version of the CSM shall include a certification statement, signature, and stamp or seal by a PE or PG, comply with the requirements of this administrative regulation, and is and shall remain protective of human health and the environment within the anticipated scope of risk, potential risk, and timeframe for which it was designed and approved by the cabinet.(3)
The cabinet shall review and approve, disapprove, or notify the applicant of any deficiencies of the CCR Groundwater Corrective Action Completion Report and the CSM pursuant to KRS 224.1-522 or 224.1-400(22), and (2)(a) of this section, as applicable.Section 8.
CCR Post-Groundwater Corrective Action Implementation Long-Term Monitoring, Operation, and Management.(1)
Consistent with the continued assessment monitoring provisions of 40 C.F.R. 257.95(f), exceedance of background concentrations alone for CCR units utilizing a management-in-place closure option under this administrative regulation shall not constitute a new plume release, instability or corrective action failure, provided plume stability criteria established under this section continue to be satisfied.(2)
For CCR units and facilities electing to close pursuant to Section 5(c)2. or 5(c)4., where closure includes, in whole or in part, a management-in-place option, the responsible party shall submit to the cabinet a CCR Groundwater Corrective Action Long-Term Monitoring, Operation, and Management Plan.(3)
The CCR Groundwater Corrective Action Long-Term Monitoring, Operation, and Management plan shall include:(a)
A groundwater monitoring network sufficient to monitor groundwater quality conditions and assess groundwater plume stability, migration, attenuation, and potential expansion;(b)
Groundwater monitoring frequencies sufficient to evaluate temporal and spatial groundwater quality trends;(c)
Groundwater plume instability trigger assessment criteria; and(d)
A statistical evaluation methodology for assessment of plume stability and instability consistent with subsection (3) of this section.(4)
The statistical evaluation of plume stability shall include:(a)
Groundwater analytical data shall be evaluated periodically to determine whether monitored constituent concentrations remain consistent with stable plume conditions or indicate potential plume expansion, migration, or attenuation;(b)
Trend evaluations shall incorporate both statistical and spatial lines of evidence;(c)
Trend analyses shall utilize the Mann–Kendall (MK) nonparametric trend test in conjunction with Sen's slope estimation, unless an alternative method approved by the cabinet is demonstrated to provide equivalent or greater statistical reliability:1.
The Mann–Kendall test shall be used to evaluate the presence, direction, and statistical significance of monotonic concentration trends over time; and2.
Sen's slope estimation shall be used to evaluate the magnitude and rate of constituent concentration change over time.(5)
Trigger criteria for potential plume instability evaluation shall include:(a)
Additional technical evaluation to be initiated if one or more of the following conditions are identified:1.
A Mann–Kendall trend test indicates a statistically significant increasing trend with a p-value less than 0.05;2.
Sen's slope analysis indicates a sustained positive rate of constituent concentration change exceeding historical baseline conditions;3.
Sen's slope confidence interval excludes zero;4.
Constituent concentrations increase during three consecutive monitoring events following adjustment for seasonal variability, precipitation trends, and other temporally correlated hydrologic influences;5.
Constituent exceedance frequency materially increases relative to baseline conditions; or6.
Groundwater plume footprint expansion or downgradient migration is observed.(b)
The occurrence of a single trigger condition shall not alone constitute a determination of plume expansion, but shall require additional technical review and evaluation of supporting multiple statistical, hydrogeologic, and spatial lines of evidence.(6)
A groundwater plume may be considered expanding when multiple lines of evidence demonstrate sustained increasing constituent concentration trends and spatial migration, including:(a)
Persistent statistically significant upward concentration trends across successive monitoring periods;(b)
Increasing Sen's slope values relative to historical baseline conditions;(c)
Measurable expansion of groundwater plume extent or concentration contours; and(d)
Evidence of downgradient plume migration toward compliance boundaries, receptors, or other sensitive environmental features.(7)
(a)
Where appropriate, additional statistical methods may be utilized to evaluate temporal changes in plume behavior, including, but not limited to:1.
Rolling trend analyses;2.
Seasonal Mann–Kendall testing;3.
Modified Mann–Kendall procedures accounting for autocorrelation; or4.
Change-point detection methods.(b)
These or other selected and approved statistical methods, significance thresholds, baseline periods, and evaluation procedures shall be documented in the approved monitoring plan and applied consistently throughout the monitoring program unless otherwise approved by the cabinet.HISTORY: COMPILER'S NOTE: 2025 RS HB 6, enacted by the General Assembly on March 27, 2025, altered the information to be provided at the time an administrative regulation is filed. Aside from formatting changes necessary to upload the regulation into the LRC's publication application, this regulation has been published as submitted by the agency.
401 KAR 46:130 Groundwater assessment and corrective action for coal combustion residuals (CCR) is approved for filing.
TONY HATTON, Deputy Secretary, for
JOHN LYONS, Secretary
APPROVED BY AGENCY: October 14, 2026
FILED WITH LRC: October 14, 2026 at 2:30 p.m.
PUBLIC HEARING AND COMMENT PERIOD: A public hearing on this administrative regulation shall be held on December 22, 2026, at 10:00 a.m. EST (9:00 a.m. CST), at 300 Sower Blvd., 1st Floor, Training Room B. Individuals interested in being heard at this hearing shall notify this agency in writing by five workdays prior to the hearing, of their intent to attend. If no notification of intent to attend the hearing was received by that date, the hearing may be cancelled. A transcript of the public hearing will not be made unless a written request for a transcript is made. If you do not wish to be heard at the public hearing, you may submit written comments on the proposed administrative regulation. Written comments shall be accepted through December 31, 2026. Send written notification of intent to be heard at the public hearing or written comments on the proposed administrative regulation to the contact person. The hearing facility is accessible to persons with disabilities. Requests for reasonable accommodations, including auxiliary aids and services necessary to participate in the hearing, may be made to the contact person at least five (5) workdays prior to the hearing.
CONTACT PERSON: Louanna Aldridge, Assistant Director II, Division of Waste Management 300 Sower Blvd., 2nd Floor Telephone: (502)782-0863 Louanna.Aldridge@ky.gov
REGULATORY IMPACT ANALYSIS AND TIERING STATEMENT
Contact Person:
Louanna Aldridge Telephone: (502) 782-0863 Louanna.Aldridge@ky.gov
(1) Provide a brief summary of:
(a) What this administrative regulation does:
This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of coal combustion residuals (CCR) in CCR units and requires entities to perform a conceptual site model.
(b) The necessity of this administrative regulation:
KRS 224.10-100 and KRS 224.50-760 authorizes the cabinet to promulgate administrative regulations for the management of special wastes. This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of CCR in CCR units and requires entities to perform a conceptual site model to demonstrate compliance equivalent to federal standards.
(c) How this administrative regulation conforms to the content of the authorizing statutes:
KRS 224.10-100 and KRS 224.50-760 authorizes the cabinet to promulgate administrative regulations for the management of special wastes. This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of CCR in CCR units and requires entities to perform a conceptual site model.
(d) How this administrative regulation currently assists or will assist in the effective administration of the statutes:
This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of coal combustion residuals (CCR) in CCR units and requires entities to perform a conceptual site model to demonstrate compliance equivalent to federal standards.
(2) If this is an amendment to an existing administrative regulation, provide a brief summary of:
(a) How the amendment will change this existing administrative regulation:
This is not applicable as this is a new administrative regulation.
(b) The necessity of the amendment to this administrative regulation:
This is not applicable as this is a new administrative regulation.
(c) How the amendment conforms to the content of the authorizing statutes:
This is not applicable as this is a new administrative regulation.
(d) How the amendment will assist in the effective administration of the statutes:
This is not applicable as this is a new administrative regulation.
(3) List the type and number of individuals, businesses, organizations, or state and local governments affected by this administrative regulation:
Six (6) utility companies or any new owner/operator of a CCR unit, Division of Waste Management, Division of Water, Division of Enforcement, Kentucky Transportation Cabinet, and potentially all Kentucky counties and ratepayers of the Commonwealth.
(4) Provide an analysis of how the entities identified in question (3) will be impacted by either the implementation of this administrative regulation, if new, or by the change, if it is an amendment, including:
(a) List the actions that each of the regulated entities identified in question (3) will have to take to comply with this administrative regulation or amendment:
This administrative regulation is an adoption of federal regulations and will require sites to submit internet reporting requirements to the Division of Waste Management and perform a conceptual site model at CCR facilities.
(b) In complying with this administrative regulation or amendment, how much will it cost each of the entities identified in question (3):
The costs associated with complying with this administrative regulation are unknown and are dependent on the size of facilities and number of CCR units at the facility.
(c) As a result of compliance, what benefits will accrue to the entities identified in question (3):
This administrative regulation will benefit the regulated entities by being consistent with the federal regulations, thereby only having one standard with which they must comply.
(5) Provide an estimate of how much it will cost the administrative body to implement this administrative regulation:
(a) Initially:
The administrative body has personnel costs associated with the review and approval of documents and inspections conducted. The cost of implementation of the CCR program, including this administrative regulation, is estimated to be $420,800.
(b) On a continuing basis:
The cost of implementation of the CCR program, including this administrative regulation, is estimated to be $420,800 on an annual basis.
(6) What is the source of the funding to be used for the implementation and enforcement of this administrative regulation:
All funding needed for this administrative regulation will be sourced from the CCR facility annual fee in addition to a one-time grant of $136,000.
(7) Provide an assessment of whether an increase in fees or funding will be necessary to implement this administrative regulation, if new, or by the change if it is an amendment:
This administrative regulation has an indirect fee structure established in 401 KAR 46:120.
(8) State whether or not this administrative regulation establishes any fees or directly or indirectly increases any fees:
This regulation does not establish any fees directly or indirectly.
(9) TIERING: Is tiering applied?
(Explain why or why not) Tiering is not applied to this administrative regulation as all entities are treated the same.
FEDERAL MANDATE ANALYSIS COMPARISON
(1) Federal statute or regulation constituting the federal mandate.
40 C.F.R. 257.50-257.107
(2) State compliance standards.
KRS 224.10-100, 224.50-760
(3) Minimum or uniform standards contained in the federal mandate.
40 C.F.R. 257.50-257.107
(4) Will this administrative regulation impose stricter requirements, or additional or different responsibilities or requirements, than those required by the federal mandate?
This administrative regulation is more prescriptive to demonstrate compliance equivalent with federal standards by establishing conceptual site model procedures.
(5) Justification for the imposition of the stricter standard, or additional or different responsibilities or requirements.
The imposition of these additional standards is necessary in order to protect Kentucky’s karst geography and ensure compliance equivalent to the federal standards.
FISCAL IMPACT STATEMENT
(1) Identify each state statute, federal statute, or federal regulation that requires or authorizes the action taken by the administrative regulation.
KRS 224.10-100, 224.50-760
(2) Identify the promulgating agency and any other affected state units, parts, or divisions:
Environment and Energy Cabinet, Department of Environmental Protection, Division of Waste Management
(a) Estimate the following for the first year:
Expenditures:
The administrative body has personnel costs associated with the review and approval of documents and inspections conducted. The cost of implementation of the CCR program, including this administrative regulation, is estimated to be $420,800.
Revenues:
There are no known revenues for the promulgating agency in this administrative regulation.
Cost Savings:
There are no known cost savings for the promulgating agency in this administrative regulation.
(b) How will expenditures, revenues, or cost savings differ in subsequent years?
The effective administration of the CCR program is estimated to cost $420,800 annually. As CCR surface impoundment facilities move all units into post closure, the annual fee decreases as established in 401 KAR 46:120.
(3) Identify affected local entities (for example: cities, counties, fire departments, school districts):
All Kentucky counties where CCR landfills or surface impoundments may be sited, or where beneficial reuse of CCR may be utilized.
(a) Estimate the following for the first year:
Expenditures:
There are no known expenditures for local entities in this administrative regulation.
Revenues:
There are no known revenues for local entities in this administrative regulation.
Cost Savings:
There are no known cost savings for local entities in this administrative regulation.
(b) How will expenditures, revenues, or cost savings differ in subsequent years?
There are no known expenditures, revenues, or cost savings for local entities in this administrative regulation.
(4) Identify additional regulated entities not listed in questions (2) or (3):
Utility Companies: Six (6)
(a) Estimate the following for the first year:
Expenditures:
There are no known expenditures for additional regulated entities in this administrative regulation. The annual fee for a CCR facility is $30,000, unless all CCR units are in post-closure in which case the annual fee is decreased to $5,000 as established in 401 KAR 46:120.
Revenues:
There are no known revenues for additional regulated entities in this administrative regulation.
Cost Savings:
There are no known cost savings for additional regulated entities in this administrative regulation.
(b) How will expenditures, revenues, or cost savings differ in subsequent years?
There are no known expenditures, revenues, or cost savings for additional regulated entities in this administrative regulation.
(5) Provide a narrative to explain the:
(a) Fiscal impact of this administrative regulation:
The CCR program, including this administrative regulation will cost approximately $420,800 each year to effectively administer.
(b) Methodology and resources used to determine the fiscal impact:
The Division of Waste Management estimates the program to require 3.3 full-time equivalent (FTE) positions in order to effectively administer the program estimated to cost $420,800.
(6) Explain:
(a) Whether this administrative regulation will have an overall negative or adverse major economic impact to the entities identified in questions (2) - (4). ($500,000 or more, in aggregate)
There is no major economic impact from this administrative regulation.
(b) The methodology and resources used to reach this conclusion:
The amendments to this administrative regulation will not have a major economic impact as the estimated costs associated with the CCR program are less than $500,000 and funded by CCR annual fees. A total of 14 CCR facilities paying $30,000 annually totals $420,000.
ENERGY AND ENVIRONMENT CABINET
Department for Environmental Protection
Division of Waste Management
(New Administrative Regulation)
401 KAR 46:130.Groundwater assessment and corrective action for coal combustion residuals (CCR).
Section 1.
Groundwater Assessment, Remedy Selection, and Corrective Action. Except as established in this administrative regulation, the groundwater assessment, selection of remedy, and corrective action requirements for a CCR unit shall be as established in C.F.R. 257.95 through 257.98. The requirements established in 40 C.F.R. 257.96(a) shall be replaced with:(1)
(a)
Within 90 days of finding that any constituent listed in Appendix IV in 40 C.F.R. Part 257 above the maximum contaminant level (MCL) as established in 401 KAR 30:031, or significant level exceeding the groundwater protection standard established in 40 C.F.R. 257.95(h) for parameters that have no MCL, or immediately upon detection of a release from a CCR unit, the owner or operator must initiate an assessment of corrective measures to prevent further releases, to remediate any releases, and to restore affected area to original conditions. The assessment of corrective measures must be completed within 90 days, unless the owner or operator demonstrates the need for additional time to complete the assessment of corrective measures due to site-specific conditions or circumstances.(b)
For parameters that have no MCLs, a significant increase over background shall be determined using a statistical test established in 40 C.F.R. 257.93. If after assessment monitoring, the parameters remain below the standard established in 40 C.F.R. 257.95(h), no other parameter exceeds a groundwater protection standard, and plume stability has been demonstrated pursuant to this regulation, the permittee may resume detection monitoring.(2)
(a)
The assessment of corrective measures, the application of approved corrective measures, including long-term monitoring and maintenance shall be based upon a sitewide conceptual site model performed pursuant to 401 KAR 46:130 which discusses short-term and long-term exposure risks associated with the release and proposed remedies. Short-term risks, including a cost-benefit evaluation of any removal activities, shall consider localized and environmental impacts such as increased road hazards, increased risk of additional releases, and increased emissions.(b)
Monitoring data produced during any assessment monitoring period required by 40 C.F.R. 257.95 shall be incorporated into the conceptual site model (CSM) performed pursuant to 401 KAR 46:130.(3)
The owner or operator must obtain a certification from a qualified professional attesting that the demonstration is accurate.(4)
The 90-day deadline to complete the assessment of corrective measures may be extended for no longer than 60 days.(5)
The owner or operator shall submit the assessment required by this section to the Director of the Division of Waste Management for review and approval.(6)
Upon approval by the cabinet, the owner or operator must also include the demonstration in the annual groundwater monitoring and corrective action report required by 40 C.F.R. 257.90(e).Section 2.
Karst Terrain. Karst terrain requirements shall be as established in 401 KAR 46:110, Section 9.Section 3.
Groundwater Assessment Monitoring.(1)
Except as provided in this section, the requirements for a groundwater assessment monitoring program shall be as established in 40 C.F.R. 257.95(g).(2)
To implement the requirements in 40 C.F.R. 257.95(g)(1), the following procedures are established.(a)
CCR corrective action shall reduce a concentration of Contaminants of Concern (COC) in groundwater to levels below the MCLs established by 401 KAR 8:250, Section 1, ambient background values, or risk-based levels for parameters that lack an MCL.(b)
No later than February 9, 2027, the owner or operator shall submit to the cabinet, CCR Corrective Action Plan. The CCR Groundwater Corrective Action Plan shall include:1.
The methods to be used to abate release of COCs;2.
The methods to be used to prevent further release of COCs;3.
A description of the means used to restore or replace contaminated water supplies;4.
The milestones and total time to complete corrective action as established in subsection (a) of this subsection; and5.
A conceptual site model as established in paragraph (e) of this subsection.(c)
Upon proposed approval of the Corrective Action Plan by the cabinet, a public notice shall be published as established in 401 KAR 46:120, Section 8.(d)
Corrective action measures shall be initiated and completed within the time period required in the permit.(e)
An owner or operator shall submit a CSM.1.
The CSM shall be scientifically and geologically sufficient to understand the release of the COCs and to enable a comprehensive and conceptual understanding of the impacts, impact boundaries, and fate and transport of the uppermost groundwater aquifer, and underlying hydraulically-connected aquifers.2.
The CSM shall also include:a.
The incorporation of all previous and relevant assessment, investigatory, and characterization work, data, and information related to defining the nature and extent of the COC contamination and impact;b.
A concise executive summary of the CSM report findings and recommendations;c.
To the extent known or reasonably obtained, a site description and history;d.
In accordance with C.F.R. § 257.75 and to the extent known or reasonably obtained, a comprehensive, accurate, and complete discussion regarding the identification, regulatory, operational, and investigational history of the site, and a chronology of events related to all CCR units and CCR Areas of Potential Concern (APC), releases, and potential releases. At a minimum, this discussion shall include the elements of C.F.R Part 257.75 (c)(1)(i) through (xiv) and (d)(1)(i) through (xiii).e.
To the extent known or reasonably obtained, a description of the land use status of the site and adjacent properties;f.
A map depicting domestic use well, municipal well or well field, and well head protection area survey within a radius commensurate with the COCs under investigation and their characteristic fate and transport within the specific groundwater regime impacted;g.
A description and analysis of the geologic and hydrogeologic setting relevant to the release;h.
A description, discussion, and analysis of the nature and extent of the mass discharge strength of the source and plume;i.
An assessment of the applicability of the Darcy Flux concept as defined in this administrative regulation or other groundwater velocity and flow concepts, consistent with the specific geologic and hydrogeologic setting;j.
A description, discussion, and analysis of groundwater impacts that references the appropriate maps, figures, tables, and appendices regarding the:(i)
COCs;(ii)
Plume source area;(iii)
Plume migration pathway;(iv)
Existing and potential future points of exposure and extraction points;(v)
Plume terminus; and(vi)
COC groundwater impact trends per monitoring point, along a cross-section of the plume's major axis length in the predominant downgradient direction, and across the plume's minor axis width;k.
A description, discussion, and analysis of the nature and extent of impacted surface and subsurface soil, as applicable;l.
A description, discussion, and analysis of the nature and extent of impacted sediment, as applicable;m.
A description, discussion, and analysis of the nature and extent of impacted surface water(s), as applicable;n.
A description, discussion, and analysis of ecological impacts, as applicable;o.
Conclusions and recommendations;p.
Figures, maps, graphs, and tables, including:(i)
Aerial photographs;(ii)
A site survey map;(iii)
A site map of the source;(iv)
Site maps of historic and recent soil sampling locations and data;(v)
Site maps of historic and existing monitoring wells;(vi)
Site maps of historic and recent monitoring wells and data;(vii)
Site maps of historic and recent groundwater potentiometric surface with flow trend direction indicated;(viii)
Site maps indicating groundwater COCs isoconcentration contours;(ix)
A map of the portion of the 7.5-minute United States Geological Survey (USGS) Topographic Map or a map providing equivalent information depicting the location of the site, name of the map, latitude and longitude labels, and a map scale;(x)
A map of the portion of the 7.5-minute USGS Geologic Quadrangle Map, or a map providing equivalent information depicting the location of the site, the name of the map, latitude and longitude labels, a map scale, and a description of the site geology from the geologic quadrangle;(xi)
Geologic and soil cross sections depicted along the major and minor axes of the contaminant plume indicating the plume source, migration pathway, exposure and extraction points, as applicable, and plume terminus, soil and lithological stratigraphy, hydraulically significant geologic features, average depth groundwater elevation, average depth to plume elevation, and other pertinent subsurface features, including underground utilities and preferred pathways;(xii)
A site bedrock contour map, as applicable;(xiii)
Hydrographs for all monitoring wells and alternative groundwater monitoring points;(xiv)
Concentration versus time plots for each monitoring well and alternative groundwater monitoring points for trend analysis;(xv)
Concentration, as average of mass across monitoring wells and alternative groundwater monitoring points along the primary major and minor axes versus time plots for trend analysis;(xvi)
Groundwater elevation data tables for all historic and existing monitoring wells and alternative groundwater monitoring points, which shall at a minimum, include all relevant current and historic gauging data for each monitoring well and alternative groundwater monitoring points, all relevant monitoring well and alternative groundwater monitoring point's identification designations, groundwater gauging dates, and identification of any abandoned wells;(xvii)
Groundwater analytical data tables for all historic and existing monitoring wells and alternative groundwater monitoring points, which shall at a minimum include all relevant current and historic analytical data for each monitoring well and alternative groundwater monitoring points, all relevant monitoring well and alternative groundwater monitoring point's identification designations, sample collection dates, analytical results, and identification of any abandoned wells;(xviii)
Soil analytical data tables for all soil samples collected, which shall at a minimum include sample identification numbers, depths sampled, sample collection dates, analytical results, and identification of any excavated sampled areas;(xix)
Current photographs of the site and adjacent sites;(xx)
Copies of all boring logs, logged by a geologist; and(xxi)
Copies of all monitoring well records, including records for abandoned monitoring wells;q.
The owner or operator of any facility regulated under this section shall obtain a certification statement, signature, and stamp or seal by a qualified Professional Geologist (PG), stating that the CSM complies with the requirements of this administrative regulation, that all geologic and hydrogeologic data, analysis, and interpretations comply with KRS Chapter 322A and has been performed, designed, utilized, and implemented by a PG or a geologist-in-training under the direct supervision and review of a PG to assess and provide for the protectiveness of public health and welfare and the environment to the fullest extent possible;r.
The owner or operator of any facility regulated under this regulation shall obtain a certification from a qualified Professional Engineer (PE) stating that the clause d. of this subparagraph meets the requirements of C.F.R, Part 257.75;s.
The owner or operator of any facility regulated under this section must provide a notarized, dated, and signed certification that all data, site evaluation, and information provided by the owner or operator to the PE and PG consultant, and contained in the PE and PG certified CSM, to the best of their knowledge and understanding, is true, accurate, and complete, with the following statement signed by the owner or operator or an authorized representative: "I certify under penalty of law that I have personally examined and am familiar with the information submitted in this demonstration and all attached documents, and that, based on my inquiry of those individuals immediately responsible for obtaining the information, I believe that the submitted information is true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment.";t.
The Groundwater CCR Plume Geochemical Study and Analysis (GSA) Demonstration established in Section 4 shall be submitted as an appendix to the CSM.(f)
1.
For CCR facilities subject to this administrative regulation, the requirements established in 40 C.F.R. 257.90(e) for the groundwater monitoring and corrective action report shall be replaced with the requirement for the owner or operator to submit an annual CCR Corrective Action Update no later than January 31.2.
The CCR Groundwater Corrective Action Update shall include:a.
Any updated information relevant to the requirements in the CSM; andb.
The requirements established by 40 C.F.R. 257.90(e).Section 4.
Groundwater Coal Combustion Residuals (CCR) Plume Geochemical Study and Analysis (GSA) Demonstration.(1)
The party or applicant shall perform and submit a GSA Demonstration Report of the CCR groundwater plume's geochemical conditions and state.(2)
A GSA Demonstration Report is a documented study and analysis performed to demonstrate the geochemical conditions and state of the CCR groundwater plume. The GSA Demonstration Report is an evaluation of geochemical plume conditions and external parameters that may limit or promote the stability or instability of metals mobilization within the groundwater aquifer.(3)
The GSA Demonstration Report general provisions and core requirements shall address and at a minimum include the following scientific, geologic, and technical criteria:(a)
Data, analysis, and presentations of the plume status in space (lateral and vertical communication) and time;1.
Expansion;2.
Steady-state; or3.
Decay.(b)
Data, analysis, and presentations of the geochemical plume status, geochemical parameters and conditions that limit or promote stability or instability for metals mobilization in the groundwater aquifer:1.
pH conditions;2.
Redox conditions;3.
Soil sorption capacity conditions; and4.
Mineral equilibrium conditions.(c)
Data, analysis, and presentations of plume mass discharge rate (Md);(d)
Data, analysis, assessment, and presentations of existing, future likely, and future potential groundwater extraction points mass extraction rate (Me) of existing and future potential and likely groundwater extraction point receptors;(e)
Data, analysis, and designation of plume magnitude;(4)
The GSA Demonstration Report prepared and submitted for agency review and approval to support a geochemical stability determination shall, at a minimum, include the following technical elements, supporting data, analytical evaluations, and performance metrics necessary to demonstrate and document the geochemical study:(a)
A concise executive summary of the GSA Demonstration Report's findings, conclusions, and recommendations.(b)
An evaluation of Plume Status in Space and Time, including supporting data, statistical analyses, hydrogeologic interpretation, and technical discussion addressing the following:1.
Statistically significant concentration trends for Appendix IV and other applicable COCs at plume boundary monitoring wells,2.
Testing, data evaluation, and analysis of downgradient groundwater conditions relative to plume expansion, steady-state behavior, or attenuation decay for Appendix IV and other applicable COCs beyond the historical plume footprint,3.
Testing, data and analysis downgradient of the groundwater plume historical footprint, including:a.
In relation to existing groundwater extraction points inducing and influencing the groundwater gradient related to the groundwater CCR plume, andb.
In relation to applicable likely future and potential future Groundwater Extraction Point(s) inducing and influencing related to the groundwater gradient on the groundwater CCR plume.4.
Characterization of upgradient natural background groundwater conditions outside areas exhibiting plume expansion, steady-state conditions, or attenuation for Appendix IV and other applicable COCs relative to the historical plume footprint; and5.
Demonstration and evaluation of groundwater mass flux and mass discharge for Appendix IV and other applicable COCs to determine whether the groundwater plume is expanding, stable, or decreasing.(c)
An evaluation of geochemical plume conditions and external parameters that may limit or promote the stability or instability of metals mobilization within the groundwater aquifer.(d)
The geochemical evaluation shall include supporting data, testing results, analyses, geochemical interpretation, and technical discussion addressing the following:1.
Identification and evaluation of geochemical conditions demonstrating whether site-specific conditions facilitate, limit, or arrest the mobility of Appendix IV metals and other applicable COCs;2.
Evaluation of whether the mobility or immobility of Appendix IV and other applicable COCs is spatially and temporally stable and persistent on a seasonal and annual basis, or whether such conditions are temporally or spatially variable, uncertain, or demonstrably unstable; and3.
Geochemical testing, data evaluation, analysis, and interpretation including, at a minimum:a.
Identification of the primary source type, including the anthropogenic source matrix and relevant aquifer matrix materials;b.
Seasonal and annual testing, analysis, and evaluation of oxidation–reduction (redox) conditions and trends associated with stability or instability of Appendix IV and other applicable COCs;c.
Seasonal and annual testing, analysis, and evaluation of aerobic and anaerobic redox conditions within the subject aquifer groundwater and their relationship to Appendix IV and other applicable COCs;d.
Seasonal and annual testing, analysis, and evaluation of pH stability, variability, or instability within the subject aquifer groundwater in relation to Appendix IV and other applicable COCs;e.
Testing and analysis of pH conditions, including acidic, neutral, or alkaline conditions, within the subject aquifer groundwater and their relevance to Appendix IV and other applicable COCs;f.
Testing and analysis of soil and aquifer material sorption capacity, including pedololithic soils, anthropogenic fill materials, and aquifer matrix materials, evaluated both laterally and vertically;g.
Demonstration of whether geochemical factors associated with the CCR source are expanding laterally or downgradient within the aquifer system; andh.
Testing, analysis, and modeling evaluating geochemical mineral equilibrium conditions associated with the CCR source and the groundwater aquifer.4.
Geochemical source and groundwater conditions shall be demonstrated and evaluate geochemical conditions at a site utilizing:a.
The most recent published version of the United States Geologic Survey's (USGS) Ph, Redox Equilibrium (PHREEQC) model as the minimal acceptable means; orb.
The Registered Professional Geologist (PG) responsible for the applicable certifications may propose another scientifically valid method, model, or combination of methods. Use of an alternative approach shall be supported by sufficient technical documentation demonstrating to the satisfaction of the cabinet that the proposed approach:(i)
Is demonstrated to serve the same technical purpose as the USGS PHREEQC model for the specific geochemical evaluation being performed;(ii)
Is demonstrated to provide capabilities that are equivalent to or technically superior to those of the USGS PHREEQC model for the specific site conditions and evaluation objectives; andc.
The above demonstrations have been technically reviewed and approved by a cabinet Registered Professional Geologist (PG) prior to its use as the basis for the applicable GSA Demonstration Report certification.5.
Analysis and demonstration of whether the first aquifer immediately beneath the upper impacted aquifer is in communication with the upper impacted aquifer, or is impacted by Appendix IV and other applicable COCs spatially, seasonally, or annually from the impacted upper aquifer.(e)
Groundwater Plume Geochemical Spatial Status (Plume Footprint). In order to demonstrate the lateral and downgradient spatial status of the groundwater plume spatial maps and figures to scale shall be prepared and submitted isoconcentration (plane view) time-sequenced plume maps for each Indicator constituent, Appendix IV metal, and other identified applicable COCs using and showing 3 to 5 representative seasonal wet period and dry period events, over 2 to 4 years. Isoconcentration time-sequenced maps shall include at a minimum:1.
Consistent contour intervals;2.
The primary source area;3.
The plume core;4.
The plume's boundaries; background bounds, leading edge, and side lateral bounds;5.
Overlays of the dominant seasonal and annual groundwater flow direction;6.
The location of all sentinel and monitoring wells;7.
The location of all existing groundwater extraction points; and8.
Standard mapping components, which shall include:a.
Map title;b.
Compass rose or north arrow;c.
Map legend or key;d.
Inset map;e.
Locator map;f.
Map scale;g.
Data frame;h.
Source; andi.
Professional Geologist (P.G.) Stamp.(f)
Groundwater Plume Geochemical Vertical Status (Cross-Sections). In order to demonstrate the vertical and hydrogeologic vertical communication status of the groundwater plume vertical geologic and groundwater cross-section with scaled vertical exaggeration shall be prepared and submitted.1.
Prepare hydrostratigraphic vertical concentration indicated plume cross sections for each Indicator constituent, Appendix IV metal, and other identified applicable COCs.2.
Hydrostratigraphic vertical concentration indicated plume cross sections shall include:a.
Well/boring identification;b.
Well/boring map location inset;c.
Vertical and horizontal scales;d.
Electrical logs;e.
Screened intervals;f.
Geologic data;g.
Soil type;h.
Stratigraphy;i.
Geologic features;j.
Age of geologic units;k.
Stratigraphic correlations;l.
Static groundwater level;m.
Metals concentrations by depth; andn.
Professional Geologist (P.G.) Stamp.(g)
Groundwater Plume Geochemical Temporal Status (Trend Analysis). In order to demonstrate the temporal status of the groundwater plume trend, analysis for Appendix IV and other applicable COCs shall be prepared and submitted.1.
Temporal stability trend analysis shall use;a.
Mann-Kendall non-parametric statistical determination method test to analyze if trends over time are present. Mann-Kendall determines if the COC trends are increasing, decreasing, stable;b.
Sen's Slope non-parametric statistical tests to quantify the strength and rate of change over time of an identified trend. Sen's Slope supports corrective action decisions and risk analysis;c.
Other appropriate statistical method for groundwater analysis listed in 401 KAR 48:300, Section 9 or U.S. EPA's Groundwater Statistics Tool; ord.
Other appropriate and applicable statistical methods for groundwater analysis upon approval by the cabinet in the context of a specific report if use of the alternative statistical approach is supported by sufficient technical documentation demonstrating to the satisfaction of the cabinet that the proposed approach:(i)
Is demonstrated to serve the same technical purpose as the statistical model, Mann-Kendall or Sen's Slope, for the specific geochemical evaluation being performed;(ii)
Is demonstrated to provide capabilities that are equivalent to or technically superior to those of the Mann-Kendall or Sen's Slope for the specific site conditions and evaluation objectives; and(iii)
The demonstration has been technically reviewed and approved by a cabinet Registered Professional Geologist (PG) prior to its use as the basis for the applicable GSA Demonstration Report certification.2.
Mann-Kendall and Sen's Slope non-parametric statistical tests shall be applied to:a.
Unit boundary wells;b.
Plume boundary wells (up, down, and side gradient);c.
Sentinel wells;d.
Monitoring wells; ande.
Highest concentration plume core wells.3.
Temporal stability trends shall be classified as:a.
Increasing;b.
Decreasing; andc.
No trend (stable).4.
Time-series plots demonstrating concentrations over time shall include:a.
Concentration versus time for each COC for each well;b.
Overlay of applicable regulatory standards; andc.
Highlight of long-term trends.(h)
Groundwater Plume Mass Discharge Rate Estimates, Analysis, and Demonstration. In order to demonstrate groundwater plume mass discharge status, the plume shall be evaluated system-wide in both space and time to assess plume stability, rather than relying solely on discrete point measurements. The evaluation shall include supporting data, calculations, analysis, and technical interpretation sufficient to characterize plume loading conditions. Plume mass discharge demonstrations shall include, at a minimum, the following:1.
An estimate of the mass discharge rate at the groundwater plume terminus for all CCR Appendix IV COCs and other applicable COCs that exceed applicable regulatory or risk-based levels.2.
An estimate of the mass discharge rate at the groundwater plume terminus for all CCR Appendix IV and other applicable COCs exceeding their applicable regulatory levels, compared to an estimated mass extraction rate for all existing, likely future, and potential future groundwater extraction points using a baseline concentration of 0.002 parts per million (ppm) (mg/L), corresponding to the MCL for mercury (Hg).3.
An estimate of the daily mass discharge rate at the groundwater plume terminus for all CCR Appendix IV and other applicable COCs exceeding applicable regulatory levels, compared to the estimated daily mass extraction rates for all existing and reasonably foreseeable future groundwater extraction points calculated for each applicable regulatory level. This comparison shall determine whether the daily mass discharge rates at the plume terminus for each CCR Appendix IV and other applicable COC exceedance are greater than, equal to, or less than the estimated daily mass extraction rates for applicable existing, likely future, and potential future groundwater extraction points.(i)
In order to assess the groundwater plume mass discharge and groundwater extraction point mass extraction rates, the owner or operator shall determine:1.
The groundwater plume mass discharge rate (Md) at the plume terminus; and2.
The mass extraction rate (Me) at all applicable:a.
Existing groundwater extraction points;b.
Likely future groundwater extraction points; andc.
Potential future groundwater extraction points.(j)
Methodology.1.
The calculation of mass discharge (Md) and mass extraction (Me) may utilize the standard data tables identified as Tables 1 through 3 of this administrative regulation below:| Table 1. Kentucky Rivers Average Flow Rates as a Groundwater Extraction Point. | |||
| Kentucky River | Flow Rate(Cu.Ft./Sec.) | Flow Rate(Gal./Sec.) | Flow Rate(Gal./da.) |
| Beargrass Creek | 103 | 770 | 66,570,640 |
| Elkhorn Creek | 677 | 5,064 | 437,556,534 |
| Tradewater River | 1,070 | 8,004 | 691,559,072 |
| North Fork Kentucky River | 1,099 | 8,221 | 710,302,262 |
| Salt River | 1,704 | 12,747 | 1,101,323,980 |
| Barren River | 2,501 | 18,709 | 1,616,438,541 |
| Big Sandy River | 5,007 | 37,455 | 3,236,108,667 |
| Licking River | 5,694 | 42,594 | 3,680,128,370 |
| South Fork Licking River | 275 | 2,057 | 177,737,145 |
| Kentucky River | 8,924 | 66,756 | 5,767,731,924 |
| Green River | 14,574 | 109,021 | 9,419,422,350 |
| Cumberland River | 37,250 | 278,649 | 24,075,304,141 |
| Tennessee River | 70,575 | 527,938 | 45,613,814,490 |
| Ohio | 281,500 | 2,105,766 | 181,938,204,450 |
| Ohio-Mississippi at Confluence | 593,000 | 4,435,948 | 383,265,915,591 |
| Table 2. Stream and River Classification Average Flow Rates | ||||
| *Stream River Flow Class | Base FlowCubic Feet per Second (cfs) | Base FlowGallons per Day (gpd) | Kentucky Rivers and Streams Examples | Notes |
| Very Small Stream Headwaters | <1 | <646,000 | Unnamed headwater tributaries to Red River (eastern Kentucky uplands). Small tributaries to Elkhorn Creek in Fayette/Scott counties. | **1st Order Stream. |
| Small Streams | 1–100 | 0.65–64.6 million | Upper Floyd's Fork, Elkhorn Crk., Upper tributaries to Licking River. | **2nd and 3rd Order Streams. |
| Medium Rivers | 100–10,000 | 64.6 million–6.46 billion | Salt, Big Sandy, Licking, Barren, and Kentucky Rivers. | **4th, 5th, and 6th Order Rivers. |
| Large Rivers | 10,000–100,000 | 6.46–64.6 billion | Green, Cumberland, and Tennessee Rivers. | **7th and 8th Order Rivers. |
| Major Continental Rivers | >100,000 | >64.6 billion | Ohio and Mississippi Rivers. | **8th Order Rivers. |
| References: *Based on Leopold, L, Wolman, M.G., Miller, J.P. Fluvial Process in Geomorphology. (1964). **Based on Strahler Stream Order (1952). | ||||
| Table 3. Spring Classification Average Flow Rates | ||||
| *Stream/River Magnitude Order | DischargeCubic Feet per Second (cfs) | DischargeGallons per Day (gpd) | Kentucky Spring and Seep Examples | Notes |
| 8th (Small Seep, Minor Spring) | <0.0003 cfs | <180 | Minor hillside discharges, E. Kentucky Coal Field fractured sandstones & shales, Upland residual soils over limestone. | Often seasonal; common in shallow perched systems. |
| 7th (Small Seep, Minor Spring) | 0.0003–0.002 cfs | 180–1,440 | Minor hillside discharges, E. Kentucky Coal Field fractured sandstones & shales, Upland residual soils over limestone. | Often seasonal; common in shallow perched systems. |
| 6th (Small Spring) | 0.002–0.02 cfs | 1,440–14,400 | Farmstead springs, Spring box domestic supplies, Hillside seeps feeding small tributaries. | Typical rural domestic supply range. |
| 5th (Small Spring) | 0.02–0.22 cfs | 14,400–144,000 | Farmstead springs, Spring box domestic supplies, Hillside seeps feeding small tributaries. | Typical rural domestic supply range. |
| 4th (Moderate Spring) | 0.22–1 cfs | 144,000–646,000 | Common in central Kentucky karst belt. Captured for rural water supply or forming small perennial headwaters. | Capable of forming a perennial stream channel. |
| 3rd (Large Spring) | 1–10 cfs | 0.65–6.46 million | Shaker, Elizabethtown. | Equivalent to a small stream baseflow. |
| 2nd (Large Spring) | 10–100 cfs | 6.46–64.6 million | Crab Orchard, Lulbegrud Crk. Sp., Booneville. | Equivalent to a small stream baseflow. |
| 1st (Regional Spring) | ≥100 cfs | ≥64.6 million | Mammoth Spring, Big Spring. | Regionally significant groundwater discharge points. |
| References: *Based on USGS Meinzer (1927) | ||||
2.
Tables 1 through 3 shall provide default or representative parameter values for groundwater flow, extraction rates, and receptor classifications where site-specific data is unavailable or insufficient.3.
Where site-specific hydrogeologic data is available, the owner or operator may use measured values in lieu of default tabulated values, unless otherwise approved by the cabinet.(k)
The calculated Md at the plume terminus and Me at all existing and applicable speculative groundwater extraction points shall be used to:1.
Classify groundwater plume magnitude;2.
Assess the plume magnitude in relation to groundwater extraction point at risk receptors and potential receptors;3.
Assess and record plume magnitude strength and status;4.
Evaluate receptor impact potential;5.
Support corrective action determinations; and6.
Evaluate and support short- and long-term risk analysis, evaluation of risk and potential risk, risk management, and institutional, engineering, and natural controls.(l)
Groundwater plume magnitude classification shall be determined based on the calculated mass discharge rate of the plume. The classification shall be derived using the mass discharge rate corresponding to the lowest applicable MCL exceedance for Appendix IV constituents or other applicable COCs, or the lowest applicable risk-based concentration level where an MCL is not available.1.
The mass discharge rate shall be expressed in grams per day (g/day).2.
Groundwater plume magnitude classification shall be classified according to the total calculated mass discharge (Md) at the plume terminus in accordance with Table 4 of this administrative regulation below:| Table 4. Groundwater Plume Magnitude Strength (5 Major Categories) | ||
| Plume Magnitude Category | Md – Mass Discharge Range (g/day) | First Plume Magnitude Impacting > Regulatory or Risk Exceedance Level at a Groundwater Extraction Point (Receptor) |
| I – De Minimis / Trace | < 0.01 | Consumptive Wells: Average domestic use well (~150 gal/day). |
| Streams/Rivers: Typically limited to ephemeral drainage or diffuse headwater seepage. | ||
| Springs: 8th–7th order minor seeps and hillside discharges (Eastern Kentucky coal field fractured sandstones & shales; upland residual soils over limestone). | ||
| II – Minor / Localized | 0.01 – 1 | Consumptive Wells: Small domestic or farmstead wells. |
| Streams/Rivers: Very small 1st order headwater streams (e.g., unnamed tributaries to the Red River; small tributaries to Elkhorn Creek in Fayette/Scott Counties). | ||
| Springs: 6th–5th order small springs (farmstead springs, spring box domestic supplies, hillside seeps feeding small tributaries). | ||
| III – Moderate / Developing | 1 – 100 | Consumptive Wells: Public supply or agricultural wells (≥100 gallons per minute). |
| Streams/Rivers: Small 2nd–3rd order streams (Upper Floyd's Fork; Elkhorn Creek; upper tributaries to Licking River; Beargrass Creek). | ||
| Springs: 4th–3rd order springs (moderate to large springs common in central Kentucky karst belt; e.g., Shaker Spring – Elizabethtown). | ||
| IV – Major / Regional | 100 – 10,000 | Consumptive Wells: High-capacity municipal or regional supply wells. |
| Streams/Rivers: Medium 4th–6th order rivers (Salt, Big Sandy, Licking, Barren, Kentucky Rivers). | ||
| Springs: 2nd–1st order large to regional springs (Crab Orchard Spring; Lulbegrud Creek Spring; Booneville Spring; Mammoth Spring; Big Spring). | ||
| V – Severe / Basin-Scale | > 10,000 | Consumptive Wells: Regional groundwater production fields. |
| Streams/Rivers: Large 7th–8th order rivers to continental-scale systems (Tennessee, Cumberland, Green Rivers; Mississippi and Ohio Rivers). | ||
| Springs: Regional karst systems with multi-mile conduit flow and basin-scale discharge influence. | ||
| Note: Groundwater Extraction Point Examples Calculated Regulatory Extraction Exceedance Rates are based on MCL of 0.002 ppm for mercury (Hg). | ||
3.
The determined groundwater plume magnitude shall be evaluated relative to all applicable groundwater extraction points located at, downgradient of, and side-gradient to the site and all evaluated applicable likely and potential future groundwater extraction points.4.
The groundwater plume calculated mass discharge rate shall be evaluated relative to all applicable existing groundwater extraction points mass extraction rates located at, downgradient of, and side-gradient to the site, and all evaluated applicable likely and potential future groundwater extraction points.(5)
Weight-of-Evidence Groundwater Plume Stability Evaluation.(a)
The demonstration of groundwater plume stability for the evaluation of risk and protection of human health and the environment for CCR units and areas of interest Appendix IV metals, and other applicable COCs, require the evaluation of multiple independent lines of evidence that collectively assess whether the plume has reached a stable configuration in space and time.(b)
Dissolved metals mobility or immobility, and consequential present or future risk(s), are primarily influenced by geochemical conditions and hydrogeologic factors. Plume stability cannot be determined solely based on individual concentration measurements at discrete wells or sampling events, nor are such decisions based on concentrations alone scientific, scientifically sound, robust, or legally defensible.(c)
Accordingly, the evaluation of plume stability shall be conducted using a weight-of-evidence framework that integrates spatial plume behavior, temporal concentration trends, plume mass and mass flux characteristics, geochemical controls on metals mobility, and potential receptor impacts.(d)
This approach is consistent with widely accepted regulatory practices applied under groundwater corrective action programs, including those explicitly stated and implemented under 40 C.F.R. Part 257 (Coal Combustion Residuals), RCRA corrective action programs, and CERCLA remedial investigations.(e)
For purposes of this regulation and its gathered information, data, evaluation, and analysis: A stable groundwater plume is defined as a plume that demonstrates the following conditions:1.
No statistically significant increasing trends in concentrations at downgradient plume boundary wells or sentinel monitoring wells;2.
No lateral or downgradient expansion of the plume footprint relative to historical monitoring data;3.
Stable or declining dissolved plume mass or mass discharge; and4.
Persistent geochemical conditions that limit metals mobility through processes such as sorption, precipitation, or co-precipitation.(f)
Evaluation of plume stability based on the scientific and technical requirements of this section shall include and yield, at a minimum, the following lines of evidence:1.
Spatial stability, demonstrated through consistent plume geometry and absence of lateral or downgradient expansion based on isoconcentration mapping and hydrostratigraphic cross sections;2.
Temporal stability, demonstrated through statistical trend analysis (e.g., Mann-Kendall or Sen's slope) and long-term time-series evaluation of COC concentrations;3.
System-scale plume behavior, demonstrated through estimates of dissolved plume mass and, where practicable, mass flux or mass discharge across downgradient transects;4.
Geochemical stability, demonstrated through evaluation of groundwater chemistry parameters that influence metals mobility and through geochemical modeling or speciation analysis where appropriate;5.
Source term conditions, including evaluation of whether the source area is controlled, removed, capped, or otherwise stabilized; and6.
Receptor protection, including confirmation that the plume remains contained on-site and does not pose a current or reasonably foreseeable future risk to downgradient receptors.(g)
The results of these evaluations are summarized for simplicity and to assist regulatory decision in the following tables:1.
Table 5. CCR Groundwater Metals Plume Stability – Decision Matrix. This decision matrix integrates multiple lines of evidence to evaluate groundwater plume behavior for metal COCs associated with coal combustion residuals (CCR) units. The matrix provides a structured, weight-of-evidence framework that considers spatial plume stability, temporal concentration trends, plume mass and mass flux, geochemical controls on metals mobility, source term conditions, and potential receptor impacts. Collectively, these factors are evaluated to support a comprehensive assessment of plume stability and to provide a transparent and regulator-defensible basis for determining plume status and the justification and effectiveness of corrective action and risk management measures; and2.
Table 6. CCR Geochemical Regulatory Decision Outcome. This table provides a structured, regulatory defensible framework for classifying the groundwater plume based on geochemical and hydrogeologic evaluation of metals COCs. Using the weight-of-evidence approach described in Table 5, the plume is assessed across multiple lines of evidence, including spatial stability, temporal trends, plume mass and mass flux, geochemical conditions, source term control, and receptor risk to assign a final classification of Unstable, Conditionally Stable, or Stable. This decision framework ensures a transparent, consistent, and scientifically justified determination regarding CCR groundwater plume behavior and the effectiveness of corrective action and risk management measures.| Table 5. CCR Groundwater Metals Plume Stability – Decision Matrix | ||||
| Line of Evidence | Unstable Condition | Conditionally Stable | Stable Condition | Decision Rule / Notes |
| Plume Footprint (Plan View) | Downgradient or lateral expansion beyond historical footprint | Minor footprint variability without sustained expansion | No expansion; consistent plume geometry across events | Use consistent contour levels; evaluate ≥3–5 multi wet/dry-year 2+ events. |
| Vertical Migration | Downward migration into deeper hydrostratigraphic units | Vertical variability within same unit | Vertically constrained within defined unit | Requires cross-sections with geology and hydrogeology showing screen intervals. |
| Boundary Well Trends | Statistically significant increasing trends | Mixed trends or no trend with short record | No increasing trends (no trend or decreasing) | Mann-Kendall and Sen's slope. |
| Sentinel Well Trends | Increasing trends | No trend with limited data | No increasing trends | Sentinel wells are high-weight evidence. |
| Plume Core Trends | Increasing trends at high-concentration wells | Mixed or stable trends | Stable or decreasing trends | Core trends support mass stability. |
| Time-Series Concentrations | Sustained increases over time | Short-term variability | Stable or declining long-term patterns | Focus on long-term signal vs noise. |
| Plume Mass | Increasing dissolved mass | Approximately stable mass | Stable or declining mass | System-scale metric; high weight evidence metric. |
| Mass Discharge | Increasing downgradient mass flux | Stable with variability | Stable or declining mass flux | Especially useful where concentrations fluctuate point to point. |
| Plume Magnitude Strength 1(See Table 4) | Groundwater plume mass discharge rate (grams/day) exceeds the applicable regulatory or applicable risk-based level, expressed as a mass extraction rate (grams/day), relative to existing or potential future groundwater extraction points. | Groundwater plume mass discharge rate (grams/day) is less than or comparable to applicable regulatory and applicable risk-based levels, expressed as a mass extraction rate (grams/day), relative to existing and likely future groundwater extraction points. | Groundwater plume mass discharge rate (grams/day) is less than applicable regulatory and applicable risk level(s) calculated as a mass extraction rate in (grams/day) relative to existing likely, and potential future groundwater extraction points. | Compares plume magnitude for Appendix IV and other applicable COCs calculated mass discharge rate (grams/day) to the regulatory-level mass extraction rate (grams/day) of existing and reasonably foreseeable downgradient groundwater extraction points. This comparison considers whether plume loading is greater than or less than applicable standards at the point of extraction, and incorporates the probability of future groundwater extraction points (e.g., domestic, public water supply, or agricultural wells) occurring within the defined planning horizon (see Table 4). |
| Plume Magnitude Strength 2(See Tables 1, 2, 3 and 4) | Site groundwater plume magnitude is sufficient, greater than, to impact existing surface water, spring, and seep surface expressed drainage features characteristic of the surrounding geography. | Site groundwater plume magnitude sufficiency is varying (+/-) within one order of magnitude, with respect to potential impacts on existing surface water, spring, and seep surface expressed drainage features typical of the surrounding geography. | Site location groundwater plume magnitude is insufficient, by one magnitude or greater, to impact existing surface water, spring, and seep surface expressed drainage features typical to the geography surrounding the site. | Compares groundwater plume mass discharge (g/day) to surrounding groundwater extraction points and drainage features classifications (streams, rivers, seeps, springs) by converting annual average flow rates (gpd) to equivalent mass extraction/loading rates (g/day) using applicable COC MCLs and risk-based concentrations to evaluate relative magnitude and receptor impact. (See Tables 1, 2, 3 and 4). |
| Geochemical Conditions | Shifting toward mobilizing conditions | Mixed or transitional conditions | Persistent immobilizing conditions | pH, redox, alkalinity, sulfate/sulfide, Fe/Mn. |
| Speciation / Solubility | Undersaturated; high mobility potential | Near equilibrium | At or near solubility limits | PHREEQC USGS or equivalent modeling. |
| Attenuation Mechanisms | No identified attenuation processes | Limited or uncertain attenuation | Documented sorption/precipitation/co-precipitation | Metals-specific line of evidence. |
| Source Term | Active or uncontrolled source | Source partially controlled | Source controlled or declining | Stability claims not demonstrable without source control. |
| Receptor / Compliance Risk | Active or imminent off-site impact | On-site only; future risk uncertain | On-site contained; no current or future risk | Includes surface water, domestic use wells, public supply wells, and agricultural use wells. |
| Table 6. CCR Geochemical Regulatory Decision Outcome | ||
| Overall Weight-of-Evidence Result | Interpretation | Regulatory Action |
| Unstable | Multiple and majority lines of evidence or the most significant indicators, demonstrate plume expansion, increasing concentration trends, or conditions favoring contaminant mobilization. | Continued corrective action required. |
| Conditionally Stable | Mixed results; no clear expansion or stabilization, due to mixed results, data gaps, or uncertainty. | Continued additional monitoring or greater focused evaluation. |
| Stable | All multiple and critical lines of evidence indicate no expansion and stable/declining conditions and concentrations. | Plume stability demonstrated, No Further Action. |
(6)
The owner or operator of any facility regulated under this section shall obtain a certification statement, signature, and stamp or seal by a qualified Professional Geologist (PG), stating that the Groundwater Coal Combustion Residuals (CCR) Plume Geochemical Study and Analysis (GSA) and report complies with the requirements of this administrative regulation, that all geologic and hydrogeologic data, analysis, and interpretations comply with KRS Chapter 322A and has been performed, designed, utilized, and implemented by a PG or a geologist-in-training under the direct supervision and review of a PG to assess and provide for the protectiveness of public health and welfare and the environment to the fullest extent possible.Section 5.
Assessment, Corrective Action, and Remedy Selection.(1)
Except as established in this section, the assessment of corrective measures, corrective action, and remedy selection shall be established in 40 C.F.R. 257.96 through 257.98.(2)
The requirements in 40 C.F.R. 257.96(e) shall be replaced with the requirement for the owner or operator to publish the approved assessment of corrective measures for notice and comment pursuant to 401 KAR 46:120, Section 8.(3)
To implement the requirements in 40 C.F.R 257.96 through 257.98, the following procedures are established.(a)
The CCR groundwater corrective action plan shall be supported by the CSM. If additional data has been obtained following submittal of the CSM, the CCR groundwater corrective action plan shall include the additional data as necessary.(b)
The groundwater corrective action plan shall include a certification statement, signature, and stamp or seal by a PE or PG that the groundwater corrective action plan was prepared to address the requirements of this administrative regulation.(c)
The responsible party shall propose one (1) of the following groundwater remedy selections in the CCR Groundwater Corrective Action Plan:1.
No action necessary in accordance with KRS 224.1-400(18)(a) if the party or applicant submits to the cabinet:a.
A CSM that complies with this administrative regulation, and supports the demonstration that no further action is necessary; andb.
A demonstration that constituents do not exceed:(i)
Target risk levels for unrestricted groundwater use for MCLs established by 401 KAR 8:250, Section 1;(ii)
Ambient background values where ambient background levels are greater than MCLs; and(iii)
Risk-based levels for constituents that lack an MCL;2.
Management in place in accordance with KRS 224.1-400(18)(b) if the responsible party or applicant submits to the cabinet:a.
A revised CSM, as necessary, that complies with 401 KAR 46:130; andb.
A CSM that supports the demonstration that management in place is, and will remain, protective of human health and the environment in perpetuity;3.
Restoration in accordance with KRS 224.1-400(18)(c), which shall apply to sites where the responsible party restores the environment through removal of COCs to below MCLs established by 401 KAR 8:250, Section 1, ambient background values, or risk-based levels for parameters that lack an MCL through source removal, source treatment, or active groundwater remediation; or4.
A combination of options established in subparagraphs 2. and 3. of this paragraph.(d)
The cabinet shall review and approve, disapprove, or notify the applicant of any deficiencies of the groundwater corrective action plan pursuant to this administrative regulation.Section 6.
CCR Groundwater Management in Place Remedy. If the responsible party proposes management in place as the groundwater remedy selection the responsible party shall comply with this section.(1)
A groundwater management in place demonstration shall be submitted to the cabinet for a groundwater management in place remedy selection that shall include:(a)
1.
The removal, reduction, or stabilization of the contamination source to the extent practicable; or2.
A demonstration that the residual contaminant source has been reduced, removed, or stabilized through previous actions or attenuation;(b)
The implementation of sustainable measures that ensure protectiveness to human health and the environment for the duration of the groundwater impact;(c)
The assessment of on- and off-site risk due to the groundwater impact's fate and transport future extents, with present and area specific future potential groundwater users and extraction points;(d)
The consideration of current and proposed or potential future land use in selecting the remedy;(e)
A plan to perform a five-year review and report to the cabinet to ensure stable and protective conditions remain in place;(f)
A demonstration of protectiveness for both current and future exposures at a potential groundwater extraction point that includes a description of the method for maintenance of engineering and institutional controls, including:1.
Annual, or other approved frequency, assessments and inspections of the engineering and institutional controls, as approved by the cabinet in the groundwater corrective action plan;2.
Annual, or other approved frequency, certification to the cabinet by the party or applicant, and a PE or PG, that the engineering and institutional controls remain protective of human health, safety, and the environment; and3.
An environmental covenant in accordance with KRS 224 Subchapter 80 as appropriate;(g)
The CCR groundwater corrective action plan shall:1.
Reduce or stabilize the plume's mass discharge below the applicable MCLs established by 401 KAR 8:250, Section 1, ambient background values, or risk-based levels for parameters that lack MCLs at the present or future potential groundwater points of extraction;2.
Permanently place the groundwater plume into a plume decay or plume steady state;3.
Prevent or control the source or plume from extending the impact further vertically or horizontally toward current or future off-site groundwater extraction points; and4.
Assess, control, or eliminate unacceptable soil vapor intrusion risk exposures as applicable to the COCs and their fate and transport.(2)
If management in place is selected as a corrective action remedy for groundwater contamination, groundwater monitoring shall be required by the cabinet. Groundwater monitoring frequency shall be based upon relevant site-specific geologic, hydrogeologic, and exposure conditions.(3)
The groundwater corrective action plan and most current version of the CSM shall include a certification statement, signature, and stamp or seal by a PE or PG, that the corrective action plan and most current version of the CSM complies with the requirements established in this administrative regulation and is protective of human health and the environment.Section 7.
CCR Groundwater Corrective Action Completion Report.(1)
The party or applicant shall submit a CCR Groundwater Corrective Action Completion Report to the cabinet which shall include:(a)
Documentation that the groundwater corrective actions were implemented, completed, and comply with the CCR Groundwater Corrective Action Plan established in Section 4 that was approved by the cabinet, and consists of;1.
Documentation of any modification from the approved CCR Groundwater Corrective Action Plan;2.
Documentation of the weight, volume, and classification of any material removed as part of the groundwater corrective action;3.
Copies of signed manifests and any other pertinent waste disposal forms;4.
Sampling procedures used for waste profile determination and restoration confirmation;5.
Sampling procedures and methods used for soil, sediment, surface water, groundwater;6.
Results from any confirmatory sampling and copies of all laboratory analytical reports; and7.
Information regarding backfill material, including where it was obtained, and any attendant analytical results;(b)
Documentation of all engineering and institutional controls implemented to contain the release, eliminate pathways of exposure, reduce exposure, or achieve a combination thereof; and(c)
A statement signed by the party or applicant certifying that the document and all attachments were prepared under the direction or supervision of the party or applicant, and the information submitted is, to the best knowledge of the party or applicant, true, accurate, and complete.(2)
(a)
The party or applicant shall revise the CSM submitted pursuant to Section 3 to reflect the groundwater corrective actions implemented and completed with revised data and information, and submit with the CCR Groundwater Corrective Action Completion Report to the cabinet.(b)
The CCR Groundwater Corrective Action Completion Report and most current version of the CSM shall include a certification statement, signature, and stamp or seal by a PE or PG, comply with the requirements of this administrative regulation, and is and shall remain protective of human health and the environment within the anticipated scope of risk, potential risk, and timeframe for which it was designed and approved by the cabinet.(3)
The cabinet shall review and approve, disapprove, or notify the applicant of any deficiencies of the CCR Groundwater Corrective Action Completion Report and the CSM pursuant to KRS 224.1-522 or 224.1-400(22), and (2)(a) of this section, as applicable.Section 8.
CCR Post-Groundwater Corrective Action Implementation Long-Term Monitoring, Operation, and Management.(1)
Consistent with the continued assessment monitoring provisions of 40 C.F.R. 257.95(f), exceedance of background concentrations alone for CCR units utilizing a management-in-place closure option under this administrative regulation shall not constitute a new plume release, instability or corrective action failure, provided plume stability criteria established under this section continue to be satisfied.(2)
For CCR units and facilities electing to close pursuant to Section 5(c)2. or 5(c)4., where closure includes, in whole or in part, a management-in-place option, the responsible party shall submit to the cabinet a CCR Groundwater Corrective Action Long-Term Monitoring, Operation, and Management Plan.(3)
The CCR Groundwater Corrective Action Long-Term Monitoring, Operation, and Management plan shall include:(a)
A groundwater monitoring network sufficient to monitor groundwater quality conditions and assess groundwater plume stability, migration, attenuation, and potential expansion;(b)
Groundwater monitoring frequencies sufficient to evaluate temporal and spatial groundwater quality trends;(c)
Groundwater plume instability trigger assessment criteria; and(d)
A statistical evaluation methodology for assessment of plume stability and instability consistent with subsection (3) of this section.(4)
The statistical evaluation of plume stability shall include:(a)
Groundwater analytical data shall be evaluated periodically to determine whether monitored constituent concentrations remain consistent with stable plume conditions or indicate potential plume expansion, migration, or attenuation;(b)
Trend evaluations shall incorporate both statistical and spatial lines of evidence;(c)
Trend analyses shall utilize the Mann–Kendall (MK) nonparametric trend test in conjunction with Sen's slope estimation, unless an alternative method approved by the cabinet is demonstrated to provide equivalent or greater statistical reliability:1.
The Mann–Kendall test shall be used to evaluate the presence, direction, and statistical significance of monotonic concentration trends over time; and2.
Sen's slope estimation shall be used to evaluate the magnitude and rate of constituent concentration change over time.(5)
Trigger criteria for potential plume instability evaluation shall include:(a)
Additional technical evaluation to be initiated if one or more of the following conditions are identified:1.
A Mann–Kendall trend test indicates a statistically significant increasing trend with a p-value less than 0.05;2.
Sen's slope analysis indicates a sustained positive rate of constituent concentration change exceeding historical baseline conditions;3.
Sen's slope confidence interval excludes zero;4.
Constituent concentrations increase during three consecutive monitoring events following adjustment for seasonal variability, precipitation trends, and other temporally correlated hydrologic influences;5.
Constituent exceedance frequency materially increases relative to baseline conditions; or6.
Groundwater plume footprint expansion or downgradient migration is observed.(b)
The occurrence of a single trigger condition shall not alone constitute a determination of plume expansion, but shall require additional technical review and evaluation of supporting multiple statistical, hydrogeologic, and spatial lines of evidence.(6)
A groundwater plume may be considered expanding when multiple lines of evidence demonstrate sustained increasing constituent concentration trends and spatial migration, including:(a)
Persistent statistically significant upward concentration trends across successive monitoring periods;(b)
Increasing Sen's slope values relative to historical baseline conditions;(c)
Measurable expansion of groundwater plume extent or concentration contours; and(d)
Evidence of downgradient plume migration toward compliance boundaries, receptors, or other sensitive environmental features.(7)
(a)
Where appropriate, additional statistical methods may be utilized to evaluate temporal changes in plume behavior, including, but not limited to:1.
Rolling trend analyses;2.
Seasonal Mann–Kendall testing;3.
Modified Mann–Kendall procedures accounting for autocorrelation; or4.
Change-point detection methods.(b)
These or other selected and approved statistical methods, significance thresholds, baseline periods, and evaluation procedures shall be documented in the approved monitoring plan and applied consistently throughout the monitoring program unless otherwise approved by the cabinet.HISTORY: COMPILER'S NOTE: 2025 RS HB 6, enacted by the General Assembly on March 27, 2025, altered the information to be provided at the time an administrative regulation is filed. Aside from formatting changes necessary to upload the regulation into the LRC's publication application, this regulation has been published as submitted by the agency.
401 KAR 46:130 Groundwater assessment and corrective action for coal combustion residuals (CCR) is approved for filing.
TONY HATTON, Deputy Secretary, for
JOHN LYONS, Secretary
APPROVED BY AGENCY: October 14, 2026
FILED WITH LRC: October 14, 2026 at 2:30 p.m.
PUBLIC HEARING AND COMMENT PERIOD: A public hearing on this administrative regulation shall be held on December 22, 2026, at 10:00 a.m. EST (9:00 a.m. CST), at 300 Sower Blvd., 1st Floor, Training Room B. Individuals interested in being heard at this hearing shall notify this agency in writing by five workdays prior to the hearing, of their intent to attend. If no notification of intent to attend the hearing was received by that date, the hearing may be cancelled. A transcript of the public hearing will not be made unless a written request for a transcript is made. If you do not wish to be heard at the public hearing, you may submit written comments on the proposed administrative regulation. Written comments shall be accepted through December 31, 2026. Send written notification of intent to be heard at the public hearing or written comments on the proposed administrative regulation to the contact person. The hearing facility is accessible to persons with disabilities. Requests for reasonable accommodations, including auxiliary aids and services necessary to participate in the hearing, may be made to the contact person at least five (5) workdays prior to the hearing.
CONTACT PERSON: Louanna Aldridge, Assistant Director II, Division of Waste Management 300 Sower Blvd., 2nd Floor Telephone: (502)782-0863 Louanna.Aldridge@ky.gov
REGULATORY IMPACT ANALYSIS AND TIERING STATEMENT
Contact Person:
Louanna Aldridge Telephone: (502) 782-0863 Louanna.Aldridge@ky.gov
(1) Provide a brief summary of:
(a) What this administrative regulation does:
This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of coal combustion residuals (CCR) in CCR units and requires entities to perform a conceptual site model.
(b) The necessity of this administrative regulation:
KRS 224.10-100 and KRS 224.50-760 authorizes the cabinet to promulgate administrative regulations for the management of special wastes. This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of CCR in CCR units and requires entities to perform a conceptual site model to demonstrate compliance equivalent to federal standards.
(c) How this administrative regulation conforms to the content of the authorizing statutes:
KRS 224.10-100 and KRS 224.50-760 authorizes the cabinet to promulgate administrative regulations for the management of special wastes. This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of CCR in CCR units and requires entities to perform a conceptual site model.
(d) How this administrative regulation currently assists or will assist in the effective administration of the statutes:
This administrative regulation establishes the requirements for groundwater assessment monitoring, assessment of corrective measures, selection of remedy, and the implementation of corrective action incident to the disposal of coal combustion residuals (CCR) in CCR units and requires entities to perform a conceptual site model to demonstrate compliance equivalent to federal standards.
(2) If this is an amendment to an existing administrative regulation, provide a brief summary of:
(a) How the amendment will change this existing administrative regulation:
This is not applicable as this is a new administrative regulation.
(b) The necessity of the amendment to this administrative regulation:
This is not applicable as this is a new administrative regulation.
(c) How the amendment conforms to the content of the authorizing statutes:
This is not applicable as this is a new administrative regulation.
(d) How the amendment will assist in the effective administration of the statutes:
This is not applicable as this is a new administrative regulation.
(3) List the type and number of individuals, businesses, organizations, or state and local governments affected by this administrative regulation:
Six (6) utility companies or any new owner/operator of a CCR unit, Division of Waste Management, Division of Water, Division of Enforcement, Kentucky Transportation Cabinet, and potentially all Kentucky counties and ratepayers of the Commonwealth.
(4) Provide an analysis of how the entities identified in question (3) will be impacted by either the implementation of this administrative regulation, if new, or by the change, if it is an amendment, including:
(a) List the actions that each of the regulated entities identified in question (3) will have to take to comply with this administrative regulation or amendment:
This administrative regulation is an adoption of federal regulations and will require sites to submit internet reporting requirements to the Division of Waste Management and perform a conceptual site model at CCR facilities.
(b) In complying with this administrative regulation or amendment, how much will it cost each of the entities identified in question (3):
The costs associated with complying with this administrative regulation are unknown and are dependent on the size of facilities and number of CCR units at the facility.
(c) As a result of compliance, what benefits will accrue to the entities identified in question (3):
This administrative regulation will benefit the regulated entities by being consistent with the federal regulations, thereby only having one standard with which they must comply.
(5) Provide an estimate of how much it will cost the administrative body to implement this administrative regulation:
(a) Initially:
The administrative body has personnel costs associated with the review and approval of documents and inspections conducted. The cost of implementation of the CCR program, including this administrative regulation, is estimated to be $420,800.
(b) On a continuing basis:
The cost of implementation of the CCR program, including this administrative regulation, is estimated to be $420,800 on an annual basis.
(6) What is the source of the funding to be used for the implementation and enforcement of this administrative regulation:
All funding needed for this administrative regulation will be sourced from the CCR facility annual fee in addition to a one-time grant of $136,000.
(7) Provide an assessment of whether an increase in fees or funding will be necessary to implement this administrative regulation, if new, or by the change if it is an amendment:
This administrative regulation has an indirect fee structure established in 401 KAR 46:120.
(8) State whether or not this administrative regulation establishes any fees or directly or indirectly increases any fees:
This regulation does not establish any fees directly or indirectly.
(9) TIERING: Is tiering applied?
(Explain why or why not) Tiering is not applied to this administrative regulation as all entities are treated the same.
FEDERAL MANDATE ANALYSIS COMPARISON
(1) Federal statute or regulation constituting the federal mandate.
40 C.F.R. 257.50-257.107
(2) State compliance standards.
KRS 224.10-100, 224.50-760
(3) Minimum or uniform standards contained in the federal mandate.
40 C.F.R. 257.50-257.107
(4) Will this administrative regulation impose stricter requirements, or additional or different responsibilities or requirements, than those required by the federal mandate?
This administrative regulation is more prescriptive to demonstrate compliance equivalent with federal standards by establishing conceptual site model procedures.
(5) Justification for the imposition of the stricter standard, or additional or different responsibilities or requirements.
The imposition of these additional standards is necessary in order to protect Kentucky’s karst geography and ensure compliance equivalent to the federal standards.
FISCAL IMPACT STATEMENT
(1) Identify each state statute, federal statute, or federal regulation that requires or authorizes the action taken by the administrative regulation.
KRS 224.10-100, 224.50-760
(2) Identify the promulgating agency and any other affected state units, parts, or divisions:
Environment and Energy Cabinet, Department of Environmental Protection, Division of Waste Management
(a) Estimate the following for the first year:
Expenditures:
The administrative body has personnel costs associated with the review and approval of documents and inspections conducted. The cost of implementation of the CCR program, including this administrative regulation, is estimated to be $420,800.
Revenues:
There are no known revenues for the promulgating agency in this administrative regulation.
Cost Savings:
There are no known cost savings for the promulgating agency in this administrative regulation.
(b) How will expenditures, revenues, or cost savings differ in subsequent years?
The effective administration of the CCR program is estimated to cost $420,800 annually. As CCR surface impoundment facilities move all units into post closure, the annual fee decreases as established in 401 KAR 46:120.
(3) Identify affected local entities (for example: cities, counties, fire departments, school districts):
All Kentucky counties where CCR landfills or surface impoundments may be sited, or where beneficial reuse of CCR may be utilized.
(a) Estimate the following for the first year:
Expenditures:
There are no known expenditures for local entities in this administrative regulation.
Revenues:
There are no known revenues for local entities in this administrative regulation.
Cost Savings:
There are no known cost savings for local entities in this administrative regulation.
(b) How will expenditures, revenues, or cost savings differ in subsequent years?
There are no known expenditures, revenues, or cost savings for local entities in this administrative regulation.
(4) Identify additional regulated entities not listed in questions (2) or (3):
Utility Companies: Six (6)
(a) Estimate the following for the first year:
Expenditures:
There are no known expenditures for additional regulated entities in this administrative regulation. The annual fee for a CCR facility is $30,000, unless all CCR units are in post-closure in which case the annual fee is decreased to $5,000 as established in 401 KAR 46:120.
Revenues:
There are no known revenues for additional regulated entities in this administrative regulation.
Cost Savings:
There are no known cost savings for additional regulated entities in this administrative regulation.
(b) How will expenditures, revenues, or cost savings differ in subsequent years?
There are no known expenditures, revenues, or cost savings for additional regulated entities in this administrative regulation.
(5) Provide a narrative to explain the:
(a) Fiscal impact of this administrative regulation:
The CCR program, including this administrative regulation will cost approximately $420,800 each year to effectively administer.
(b) Methodology and resources used to determine the fiscal impact:
The Division of Waste Management estimates the program to require 3.3 full-time equivalent (FTE) positions in order to effectively administer the program estimated to cost $420,800.
(6) Explain:
(a) Whether this administrative regulation will have an overall negative or adverse major economic impact to the entities identified in questions (2) - (4). ($500,000 or more, in aggregate)
There is no major economic impact from this administrative regulation.
(b) The methodology and resources used to reach this conclusion:
The amendments to this administrative regulation will not have a major economic impact as the estimated costs associated with the CCR program are less than $500,000 and funded by CCR annual fees. A total of 14 CCR facilities paying $30,000 annually totals $420,000.