IDAPA 58.01.11
This rule applies to any individual or entity that conducts an activity with the potential to degrade ground water.
Under Section 39-120, Idaho Code, the Department of Environmental Quality is designated as the primary agency to coordinate and administer ground water quality protection programs for the state. This rule establishes minimum requirements for protection of ground water quality through standards and an aquifer categorization process. The requirements of this rule shall serve as a basis for the administration of programs which address ground water quality. This rule does not in and of itself create a permit program.
This rule implements the following statutes passed by the Idaho Legislature:
Health and Safety -
Environmental Quality:
Scott Short
1410 N. Hilton
Boise, ID 83706
Phone: (208) 373-0191
Email: scott.short@deq.idaho.gov
www.deq.idaho.gov
This rule chapter will be reviewed in compliance with Section 67-5292, Idaho Code, and in accordance with the 8-year rule review schedule linked here.
58.01.11 – Groundwater Quality Rule
000. Legal Authority. ... 3
001. Scope. ... 3
002. Administrative Appeals. ... 3
003. (Reserved) ... 3
004. Referenced Material. ... 3
005. -- 006. (Reserved) ... 3
007. Definitions. ... 3
008. -- 149. (Reserved) ... 5
150. Implementation. ... 5
151. -- 199. (Reserved) ... 6
200. Groundwater Quality Standards. ... 6
201. -- 299. (Reserved) ... 11
300. Categorized Aquifers Of The State. ... 11
301. Management Of Activities With The Potential To Degrade Aquifers. ... 11
302. -- 349. (Reserved) ... 12
350. Procedures For Categorizing Or Recategorizing An Aquifer. ... 12
351. -- 399. (Reserved) ... 13
400. Groundwater Contamination. ... 13
401. Mining. ... 15
402. -- 999. (Reserved) ... 18
Sections 39-105, 39-107, 39-120, and 39-126, Idaho Code. (7-1-26)
This rule establishes minimum requirements for protection of groundwater quality through standards and an aquifer categorization process and serves as a basis for administering programs that address groundwater quality. This rule does not create a permit program. (7-1-26)
Persons may be entitled to appeal agency actions authorized under this chapter pursuant to IDAPA 58.01.23, “Contested Case Rules and Rules for Protection and Disclosure of Records.” (3-24-22)
Statistical Guidance for Determining Background Ground Water Quality and Degradation, Department of Environmental Quality. (7-1-26)
The terms “Board,” “Department,” and “Person” are defined in Section 39-103, Idaho Code. The term “Ground water” (Groundwater) is defined in Section 39-121, Idaho Code. (7-1-26)
01. Agricultural Chemical. Any pesticide, nutrient, or fertilizer used for the benefit of agricultural production or pest management. (7-1-26)
02. Aquifer. A geological unit of permeable saturated material capable of yielding economically significant quantities of water to wells and springs. (3-24-22)
03. Beneficial Uses. Various uses of groundwater in Idaho including, but not limited to, domestic water supplies, industrial water supplies including drinking water supplies, agricultural water supplies, aquacultural water supplies, and mining. A beneficial use is defined as actual current or projected future uses of groundwater. (7-1-26)
04. Best Available Method. Any system, process, or method that is available to the public for commercial or private use to minimize the degradation from point or nonpoint sources of contamination of groundwater quality. (7-1-26)
05. Best Management Practice. A practice or combination of practices determined to be the most effective and practical means of preventing or reducing contamination of groundwater and interconnected surface water from nonpoint and point sources to achieve water quality goals and protect the beneficial uses of the water. (7-1-26)
06. Best Practical Method. Any system, process, or method that is established and in routine use that can be used to minimize the degradation from point or nonpoint sources of contamination on groundwater quality. (7-1-26)
07. Cleanup. The removal, treatment, or isolation of a contaminant from groundwater through the directed efforts of humans or the removal or treatment of a contaminant in groundwater through management practice or the construction of barriers, trenches and other similar facilities for prevention of contamination, as well as the use of natural processes such as groundwater recharge, natural decay, and chemical or biological decomposition. (7-1-26)
08. Constituent. Any chemical, ion, radionuclide, synthetic organic compound, microorganism, waste or other substance occurring in groundwater. (7-1-26)
09. Contaminant. Any chemical, ion, radionuclide, synthetic organic compound, microorganism, waste, or other substance that does not occur naturally in groundwater or that naturally occurs at a lower concentration. (7-1-26)
10. Contamination. The direct or indirect introduction into groundwater of any contaminant caused in
whole or in part by human activities. (7-1-26)
11. Crop Root Zone. The zone that extends from the surface of the soil to the depth of the deepest crop root and is specific to a species of plant, group of plants, or crop. (3-24-22)
12. Degradation. The lowering of groundwater quality as measured in a statistically significant and reproducible manner. (7-1-26)
13. Extraction. Physical removal of ore or waste rock from mineral-bearing deposits. Extraction does not include processing, which is the removal of target minerals from ores by physical or chemical methods. (3-24-22)
14. Groundwater Quality Standard. Values, either numeric or narrative, assigned to any constituent for the purpose of establishing minimum levels of protection. (7-1-26)
15. Highly Vulnerable Groundwater. Groundwater characterized by a relatively high potential for contaminants to enter or be transported within the flow system. Determinations of groundwater vulnerability will include consideration of land use practices and aquifer characteristics. (7-1-26)
16. Irreplaceable Source. A groundwater source serving a beneficial use(s) where the reliable delivery of comparable quality and quantity of water from an alternative source in the region may be economically infeasible or precluded by institutional constraints. (7-1-26)
17. Mine Operator. Any person authorized to engage in mining activities, including without limitation those authorized by law, lease, contract, permit or plan of operation. It does not include a governmental agency that grants mineral leases or similar contracts or permits unless the agency is engaged in mining activities. (7-1-26)
18. Mining Activity. Recovery of a mineral from mineral-bearing deposits, which includes reclamation, extraction, excavation, overburden placement, disposal of tailings resulting from processing, and disposal of mineral extraction wastes, including tailings that are the result of extraction, waste rock, and other extraction wastes uniquely associated with mining. (3-24-22)
19. Mining Area. The area on or within that one (1) or more mining activities occur. The Department will determine the boundaries of the mining area. Distinct mining activities may constitute separate mining areas. (7-1-26)
20. Natural Background Level. The level of any constituent in the groundwater within a specified area as determined by representative measurements of the groundwater quality unaffected by human activities. (7-1-26)
21. Point of Compliance. The vertical surface where the Department determines compliance with groundwater quality standards as provided in Subsection 400.05 and Section 401. (7-1-26)
22. Practical Quantitation Level. The lowest concentration of a constituent that can be reliably quantified among laboratories within specified limits of precision and accuracy during routine laboratory operating conditions. Specified limits of precision and accuracy are the criteria listed in the calibration specifications or quality control specifications of an analytical method. (3-24-22)
23. Projected Future Beneficial Uses. Various uses of groundwater, such as drinking water, aquaculture, industrial, mining, or agriculture, that are practical and achievable in the future based on hydrogeologic conditions, water quality, future land use activities, and social/economic considerations. (7-1-26)
24. Recharge Area. An area where water infiltrates into the soil or geological formation from, including but not limited to precipitation, irrigation practices and seepage from creeks, streams, and lakes, and percolates to one (1) or more aquifers. (7-1-26)
25. Reclamation. The process of restoring an area affected by a mining activity to its original or another beneficial use, considering previous uses, possible future uses and surrounding topography. The objective is
to re-establish a diverse, self-perpetuating plant community and to minimize erosion, remove hazards, and maintain water quality. (7-1-26)
26. Remediation. Any action taken (1) to control the source of contamination, (2) to reduce the level of contamination, (3) to mitigate the effects of contaminants, or (4) to minimize contaminant movement. Remediation includes providing alternate drinking water sources when needed. (7-1-26)
27. Site Background Level. The groundwater quality at the hydraulically upgradient site boundary. (7-1-26)
008. -- 149. (RESERVED)
This rule establishes minimum requirements to maintain and protect groundwater quality. This rule applies to all activities with the potential to degrade groundwater quality. (7-1-26)
01. Groundwater Quality Standards. The numerical and narrative standards in Sections 200 and 301 identify minimum levels of protection for groundwater quality and will be used as a basis for: (7-1-26)
a. Evaluating or comparing groundwater quality when developing or modifying best available methods, best management practices, or best practical methods; (7-1-26)
b. Identifying permit conditions; (3-24-22)
c. Establishing cleanup levels; and (3-24-22)
d. Determining appropriate actions when groundwater quality standards are exceeded. (7-1-26)
02. Aquifer Categorization. Aquifers of the state will be categorized based on vulnerability of the groundwater, existing and projected future beneficial uses of the groundwater, existing water quality, and social and economic considerations. There will be three (3) aquifer categories, Sensitive Resource, General Resource, and Other Resource, to provide different levels of protection. The level of protection required for each category and application of standards to these categories are shown in Table I.
Table I. Level of Protection and Application of Standards to Aquifer Categories
| Category | Level of Protection | Application of Standards |
|---|---|---|
| Sensitive Resource | Apply best management practices and best available methods. This category provides the highest level of groundwater protection. | May apply stricter standards than in Section 200. |
| General Resource | Apply best management practices and best practical methods to the maximum extent practical. | Apply numerical and narrative standards in Section 200. |
| Other Resource | Apply best management practices and best practical methods to the maximum extent practical. | May apply less strict standards than in Section 200. |
(7-1-26)
a. All aquifers where there are activities with the potential to degrade groundwater quality are categorized in Section 300. Those aquifers where no activities with the potential to degrade groundwater quality are occurring will remain uncategorized until such activities are commenced. If no action is taken to categorize an aquifer when an activity(ies) with the potential to degrade groundwater quality is initiated, the aquifer will automatically be categorized as General Resource. (7-1-26)
b. Categorization will be considered when an activity with the potential to degrade groundwater
quality is proposed over an aquifer or portion of an aquifer that presently has no such activities and, based on the criteria in Section 350, the aquifer may be most appropriately categorized as Sensitive Resource or Other Resource. (7-1-26)
c. Recategorization will be considered when information on vulnerability of the groundwater, existing and projected future beneficial uses of the groundwater, existing quality of the groundwater and social and economic considerations, in conjunction with one (1) or more of the criteria in Section 350, demonstrates that the aquifer or portion of an aquifer may be more appropriate in another category. (7-1-26)
03. Groundwater-Surface Water Interconnection. The beneficial uses of interconnected surface water will be recognized when evaluating groundwater quality protection. The implementation of water quality programs ensure that the quality of groundwater that discharges to surface water does not impair the identified beneficial uses of the surface water and that surface water infiltration does not impair beneficial uses of groundwater. (7-1-26)
04. Interagency Coordination. The Department will coordinate with other federal, state, and local agencies to pursue interagency agreements when necessary to ensure implementation of this rule for activities with the potential to degrade groundwater quality. (7-1-26)
151. -- 199. (RESERVED)
The following numerical and narrative standards apply to all groundwater of the state and shall not be exceeded unless otherwise allowed in this rule. (7-1-26)
a. The Primary Constituent Standards are based on protection of human health and are identified in Table II.
| Chemical Abstract Service Number | Constituent | Standard (mg/l unless otherwise specified) |
|---|---|---|
| 7440-36-0 | Antimony | 0.006 |
| 7440-38-2 | Arsenic | 0.05 |
| 1332-21-4 | Asbestos | 7 million fibers/l longer than 10 um |
| 7440-39-3 | Barium | 2 |
| 7440-41-7 | Beryllium | 0.004 |
| 7440-43-9 | Cadmium | 0.005 |
| 7440-47-3 | Chromium | 0.1 |
| 7440-50-8 | Copper | 1.3 |
| Table Footnotes *1 No Chemical Abstract Service Number exists for this constituent. 2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coliform or E. coli is a violation of these rules. |
| Chemical Abstract Service Number | Constituent | Standard (mg/l unless otherwise specified) |
|---|---|---|
| 57-12-5 | Cyanide | 0.2 |
| 16984-48-8 | Fluoride | 4 |
| 7439-92-1 | Lead | 0.015 |
| 7439-97-6 | Mercury | 0.002 |
| *1 | Nitrate (as N) | 10 |
| *1 | Nitrite (as N) | 1 |
| *1 | Nitrate and Nitrite (both as N) | 10 |
| 7782-49-2 | Selenium | 0.05 |
| 7440-28-0 | Thallium | 0.002 |
| 15972-60-8 | Alachlor | 0.002 |
| 1912-24-9 | Atrazine | 0.003 |
| 71-43-2 | Benzene | 0.005 |
| 50-32-8 | Benzo(a)pyrene (PAH) | 0.0002 |
| 75-27-4 | Bromodichloromethane (THM) | 0.1 |
| 75-25-2 | Bromoform (THM) | 0.1 |
| 1563-66-2 | Carbofuran | 0.04 |
| 56-23-5 | Carbon Tetrachloride | 0.005 |
| 57-74-9 | Chlordane | 0.002 |
| 124-48-1 | Chlorodibromomethane (THM) | 0.1 |
| 67-66-3 | Chloroform(THM) | 0.002 |
| 94-75-7 | 2,4-D | 0.07 |
| 75-99-0 | Dalapon | 0.2 |
| 103-23-1 | Di(2-ethylhexyl) adipate | 0.4 |
| 96-12-8 | Dibromochloropropane | 0.0002 |
| 541-73-1 | Dichlorobenzene m- | 0.6 |
| 95-50-1 | Dichlorobenzene o- | 0.6 |
| 106-46-7 | 1,4(para)-Dichlorobenzene or Dichlorobenzene p- | 0.075 |
Table Footnotes
*1 No Chemical Abstract Service Number exists for this constituent.
2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coliform or E. coli is a violation of these rules.
| Table II - Primary Constituent Standards | ||
|---|---|---|
| Chemical Abstract Service Number | Constituent | Standard (mg/l unless otherwise specified) |
| 107-06-2 | 1,2-Dichloroethane | 0.005 |
| 75-35-4 | 1,1-Dichloroethylene | 0.007 |
| 156-59-2 | cis-1, 2-Dichloroethylene | 0.07 |
| 156-60-5 | trans-1, 2-Dichloroethylene | 0.1 |
| 75-09-2 | Dichloromethane | 0.005 |
| 78-87-5 | 1,2-Dichloropropane | 0.005 |
| 117-81-7 | Di(2-ethylhexyl)phthalate | 0.006 |
| 88-85-7 | Dinoseb | 0.007 |
| 85-00-7 | Diquat | 0.02 |
| 145-73-3 | Endothall | 0.1 |
| 72-20-8 | Endrin | 0.002 |
| 100-41-4 | Ethylbenzene | 0.7 |
| 106-93-4 | Ethylene dibromide | 0.00005 |
| 1071-83-6 | Glyphosate | 0.7 |
| 76-44-8 | Heptachlor | 0.0004 |
| 1024-57-3 | Heptachlor epoxide | 0.0002 |
| 118-74-1 | Hexachlorobenzene | 0.001 |
| 77-47-4 | Hexachlorocyclopentadiene | 0.05 |
| 58-89-9 | Lindane | 0.0002 |
| 72-43-5 | Methoxychlor | 0.04 |
| 108-90-7 | Monochlorobenzene | 0.1 |
| 23135-22-0 | Oxamyl (Vydate) | 0.2 |
| 87-86-5 | Pentachlorophenol | 0.001 |
| 1918-02-1 | Picloram | 0.5 |
| 1336-36-3 | Polychlorinated biphenyls (PCBs) | 0.0005 |
| 122-34-9 | Simazine | 0.004 |
| 100-42-5 | Styrene | 0.1 |
Table Footnotes
1 No Chemical Abstract Service Number exists for this constituent.
2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coliform or E. coli is a violation of these rules.
| Table II - Primary Constituent Standards | ||
|---|---|---|
| Chemical Abstract Service Number | Constituent | Standard (mg/l unless otherwise specified) |
| 1746-01-6 | 2,3,7,8-TCDD (Dioxin) | 3.0 x 10-8 |
| 127-18-4 | Tetrachloroethylene | 0.005 |
| 108-88-3 | Toluene | 1 |
| *1 | Total Trihalomethanes [the sum of the concentrations of bromodichloromethane, dibromochloromethane, tribromomethane (bromoform), and trichloromethane (chloroform)] | 0.1 |
| 8001-35-2 | Toxaphene | 0.003 |
| 93-72-1 | 2,4,5-TP (Silvex) | 0.05 |
| 120-82-1 | 1,2,4-Trichlorobenzene | 0.07 |
| 71-55-6 | 1,1,1-Trichloroethane | 0.2 |
| 79-00-5 | 1,1,2-Trichloroethane | 0.005 |
| 79-01-6 | Trichloroethylene | 0.005 |
| 75-01-4 | Vinyl Chloride | 0.002 |
| 1330-20-7 | Xylenes (total) | 10 |
| *1 | Gross alpha particle activity (including radium -226, but excluding radon and uranium) | 15 pCi/l |
| *1 | Combined beta/photon emitters | 4 millirems/year effective dose equivalent |
| *1 | Combined Radium - 226 and radium 228 | 5 pCi/l |
| *1 | Strontium 90 | 8 pCi/l |
| *1 | Tritium | 20,000 pCi/l |
| *1 | Total Coliform2 | 1 colony forming unit/100 ml |
| Escherichia coliform (E. coli) | Less than 1 viable colony or colony forming unit/100 ml using any EPA approved method | |
| Fecal coliform | Less than 1 viable colony or colony forming unit/100 ml using any EPA approved method | |
| Table Footnotes *1 No Chemical Abstract Service Number exists for this constituent. 2 An exceedance of the primary ground water quality standard for total coliform is not a violation of these rules. If the primary ground water quality standard for total coliform is exceeded, additional analysis for fecal coliform or E. coli will be conducted. An exceedance of the primary ground water quality standards for either fecal coliform or E. coli is a violation of these rules. |
(3-24-22)
b. The Secondary Constituent Standards are generally based on aesthetic qualities and are identified in Table III.
| Table III. Secondary Constituent Standards | |
|---|---|
| Constituent | Standard (mg/l unless otherwise specified) |
| Aluminum | 0.2 |
| Chloride | 250 |
| Color | 15 Color Units |
| Foaming Agents | 0.5 |
| Iron | 0.3 |
| Manganese | 0.05 |
| Odor | 3.0 Threshold Odor Number |
| pH | 6.5 to 8.5 (no units apply) |
| Silver | 0.1 |
| Sulfate | 250 |
| Total Dissolved Solids | 500 |
| Zinc | 5 |
(7-1-26)
c. Sample preservation and analytical procedures to determine compliance with the standards identified in Subsection 200.01 must be in accordance with Subsections 200.01.c.i. and ii., except that cyanide must be analyzed as weak acid dissociable cyanide, as defined in IDAPA 58.01.13, “Rules for Ore Processing by Cyanidation,” or other methods approved by the Department: (7-1-26)
i. 40 CFR Part 141, National Primary Drinking Water Regulations, Subpart C, Monitoring and Analytical Requirements, provided in IDAPA 58.01.08, “Idaho Rules for Public Drinking Water Systems”; or (7-1-26)
ii. Another method approved by the Department. (3-24-22)
02. Narrative Groundwater Quality Standards. Contaminant concentrations, alone or in combination with other contaminants or properties, may not cause the groundwater to be hazardous, deleterious, carcinogenic, mutagenic, teratogenic, or toxic. Determinations of specific numerical levels when applying this standard must be based on: (7-1-26)
a. Best scientific information currently available on adverse effects of the contaminant(s); (3-24-22)
b. Protection of a beneficial use; or (3-24-22)
c. Practical quantitation levels for the contaminant(s), if they exceed the levels identified in Subsection 200.02.a. or 200.02.b. (3-24-22)
03. Natural Background Level. If the natural background level of a constituent exceeds the standard in this section, the natural background level will be used as the standard. (7-1-26)
201. -- 299. (RESERVED)
Aquifers or portions of aquifers in the state are categorized as follows: (3-24-22)
01. Sensitive Resource. (3-24-22)
a. Spokane Valley -- Rathdrum Prairie Aquifer. (3-24-22)
i. In addition to the groundwater quality standards in Section 200, the following narrative standard applies: the aquifer may not be degraded, as it relates to beneficial uses, as a result of point source or nonpoint source activity unless it is demonstrated by the person proposing the activity that such change is justifiable as a result of necessary economic or social development. (7-1-26)
02. General Resource. All aquifers or portions of aquifers where there are activities with the potential to degrade groundwater quality of the aquifer unless otherwise listed in Subsection 300.01 or 300.03. Once an activity with the potential to degrade the groundwater quality of an uncategorized aquifer or portion of an aquifer is initiated, the uncategorized aquifer will automatically become General Resource unless petitioned into the Sensitive Resource or Other Resource category. (7-1-26)
03. Other Resource. (3-24-22)
The evaluation of activities for all aquifer categories should include water quality and hydrogeological modeling that consider existing and future conditions. (7-1-26)
01. Sensitive Resource Category Aquifers. (3-24-22)
a. Activities must be managed in a manner which maintains or improves existing groundwater quality through the use of best management practices and best available methods except when a point of compliance is set pursuant to Section 401. (7-1-26)
b. Numerical and narrative standards identified in Section 200 apply to aquifers or portions of aquifers categorized as Sensitive Resource. In addition, stricter numerical and narrative standards, for specified constituents, may be adopted pursuant to Section 350 on a case by case basis and listed in Section 300. (7-1-26)
02. General Resource Category Aquifers. (3-24-22)
a. Activities must be managed in a manner which maintains or improves existing groundwater quality through the use of best management practices and best practical methods to the maximum extent practical except when a point of compliance is set pursuant to Section 401. (7-1-26)
b. Numerical and narrative standards identified in Section 200 apply to aquifers or portions of aquifers categorized as General Resource. (7-1-26)
03. Other Resource Category Aquifers. (3-24-22)
a. Activities must be managed in a manner which maintains existing groundwater quality, except for those identified constituents which may have a less stringent standard, through the use of best management practices and best practical methods to the maximum extent practical except when a point of compliance is set pursuant to Section 401. (7-1-26)
b. Numerical and narrative standards identified in Section 200 apply to aquifers or portions of aquifers categorized as Other Resource. In addition, less strict numerical and narrative standards, for specified
constituents, may be adopted pursuant to Section 350 on a case by case basis and listed in Section 300. (7-1-26)
The following process will be used for categorizing or recategorizing an aquifer. (7-1-26)
01. Criteria for Aquifer Categories. The following criteria will be considered when a petition to categorize or recategorize aquifers or portions of aquifers is submitted to the Board. (7-1-26)
the need for categorization as an Other Resource. (7-1-26)
02. Petition Process. The Department or any other person may petition the Board to initiate rulemaking to categorize or recategorize an aquifer or portion of an aquifer pursuant to Section 67-5230, Idaho Code. In addition to the information required in a rulemaking petition, the following information must be submitted in writing by the petitioner for the identified aquifer or portion of an aquifer: (7-1-26)
a. Current category, if applicable; (3-24-22) b. Proposed category and an explanation of how one (1) or more of the criteria in Subsection 350.01 are met; (7-1-26) c. An explanation of why the categorization or recategorization is being proposed; (3-24-22) d. Location, description, and areal extent; (7-1-26) e. General location and description of existing and projected future groundwater beneficial uses; (7-1-26) f. Documentation of the existing groundwater quality; (7-1-26) g. Documentation of aquifer characteristics, where available, including, but not limited to: (3-24-22) i. Depth to groundwater; (7-1-26) ii. Thickness of the water bearing section; (3-24-22) iii. Direction and rate of groundwater flow; (7-1-26) iv. Known recharge and discharge areas; and (3-24-22) v. Geology of the area; and (7-1-26) h. Identification of any proposed standards, for specified constituents, that are more or less strict than the groundwater quality standards in Section 200, or any standards to be applied in addition to those in Section 200, and a rationale for the proposed standards. (7-1-26)
03. Preliminary Department Review. Prior to submission of a petition to the Board to categorize or recategorize an aquifer, any person may seek a preliminary review of the petition from the Department. The Department will respond to the petitioner with comments within forty-five (45) days. (7-1-26)
351. -- 399. (RESERVED)
400. GROUNDWATER CONTAMINATION.
01. Releases Degrading Groundwater Quality. No person may cause or allow the release, spilling, leaking, emission, discharge, escape, leaching, or disposal of a contaminant into the environment in a manner that: (7-1-26)
a. Causes a groundwater quality standard to be exceeded; (7-1-26) b. Injures a beneficial use of groundwater; or (7-1-26) c. Is not in accordance with a permit; consent order; or applicable best management practice, best available method, or best practical method. (7-1-26)
02. Measures Taken in Response to Degradation. (3-24-22)
a. Except when a point of compliance is set pursuant to Section 401, when a numerical standard is not exceeded, but degradation of groundwater quality is detected and deemed significant by the Department, the Department will take one (1) or more of the following actions: (7-1-26)
i. Require a modification of regulated activities to prevent continued degradation; (3-24-22)
ii. Coordinate with the appropriate agencies and responsible persons to develop and implement prevention measures for activities not regulated by the Department; (3-24-22)
iii. Allow limited degradation of groundwater quality for the constituents identified in Subsection 200.01.a. if it can be demonstrated that: (7-1-26)
(1) Best management practices, best available methods, or best practical methods, as appropriate for the aquifer category, are being applied; and (7-1-26)
(2) The degradation is justifiable based on necessary and widespread social and economic considerations; or (3-24-22)
iv. Allow degradation of groundwater quality up to the standards in Subsection 200.01.b., if it can be demonstrated that: (7-1-26)
(1) Best management practices are being applied; and (3-24-22)
(2) The degradation will not impair a beneficial use. (7-1-26)
b. The following criteria will be considered when determining the significance of degradation: (7-1-26)
i. Site specific hydrogeologic conditions; (3-24-22)
ii. Water quality, including seasonal variations; (3-24-22)
iii. Existing and projected future beneficial uses; (3-24-22)
iv. Related public health issues; and (3-24-22)
v. Whether the degradation involves a primary or secondary constituent in Section 200. (3-24-22)
03. Contamination Exceeding a Groundwater Quality Standard. The discovery of any contamination exceeding a groundwater standard that poses a threat to existing or projected future beneficial uses of groundwater requires appropriate actions, as determined by the Department, to prevent further contamination. These actions may consist of investigation and evaluation, or enforcement actions if necessary to stop further contamination or clean up existing contamination. (7-1-26)
04. Agricultural Chemicals. Agricultural chemicals found in intermittently saturated soils within the crop root zone will not be considered groundwater contaminants as long as the chemicals remain within the crop root zone, and have been applied in a manner consistent with all appropriate regulatory provisions. (7-1-26)
05. Site-Specific Groundwater Quality Levels or Points of Compliance. The Department may allow site-specific groundwater quality levels, for any aquifer category, that vary from a standard(s) in Section 200 or Section 300, or may allow site-specific points of compliance, based on consideration of effects to human health and the environment, for: (7-1-26)
a. Remediation conducted under the Department’s oversight; (3-24-22)
b. Permits issued by the Department; (3-24-22)
c. Situations where the site background level varies from the groundwater quality standard; (7-1-26)
d. Dissolved concentrations of secondary constituents listed in Section 200 of this rule. The Department may allow the use of dissolved concentrations for secondary constituents if the requesting person demonstrates that doing so will not adversely affect human health and the environment; or (3-24-22)
e. Other situations authorized by the Department in writing. (3-24-22)
401. MINING.
01. Request for Setting Point(s) of Compliance and Standards Applicable to Mining Activities. At the request of a mine operator, pursuant to this section, the Department will set a point of compliance, or points of compliance, at which the mine operator must protect current and projected future beneficial uses of the groundwater and meet the groundwater quality standards as described in Section 200 or as allowed under Subsection 400.05. Degradation of groundwater is allowed at a point of compliance if the mine operator implements the level of protection during mining activities appropriate for the aquifer category as specified in Table I of Subsection 150.02. If a request is not made, the mine operator must meet the groundwater quality standards as described in Subsection 150.01 in groundwater both within and beyond the mining area unless the Department establishes the point(s) of compliance consistent with Subsection 401.03. (7-1-26)
02. Application Process. (3-24-22)
a. If the mine operator requests a point(s) of compliance the mine operator must make a written application to the Department. The application must be accompanied by a fee of two thousand five hundred dollars ($2,500) and include the following information in sufficient detail to allow the Department to establish point(s) of compliance: (7-1-26)
i. Name, location, and mailing address of the mining operation; (3-24-22)
ii. Name, mailing address, and phone number of the mine operator; (3-24-22)
iii. Land ownership status of the mining operation (federal, state, private, or public); (7-1-26)
iv. The legal structure (corporation, partnership, etc.) and residence of the mine operator; (3-24-22)
v. The legal description, to the quarter-quarter section, of the location of the proposed mining operation; (3-24-22)
vi. Evidence the mine operator is authorized by the Secretary of State to conduct business in the state of Idaho; (3-24-22)
vii. A general description of the operational plans for the mining operation from construction through final reclamation. This description must include any proposed phases for construction, operations, and reclamation and a map that identifies the location of all mining activities; (7-1-26)
viii. A preconstruction topographic site map or aerial photos extending at least one (1) mile beyond the outer limits of the mining area, identifying and showing the location and extent of the following features: (3-24-22)
(1) All wells, perennial and intermittent springs, adit discharges, wetlands, surface waters, and irrigation ditches; (7-1-26)
(2) All public and private drinking water supply source(s) within one (1) mile of the mining area; (3-24-22)
(3) All service roads and public roads; (3-24-22)
(4) All buildings and structures within one (1) mile of the mining area; (3-24-22) (5) All special resource waters within one (1) mile of the mining area; and (3-24-22) (6) All Clean Water Act Section 303(d) listed streams, and their listed impairments, within one (1) mile of the mining area; (3-24-22) ix. To the extent such information is available, a description and location of underground mine workings and adits and a description of the structural geology that may influence groundwater flow and direction; (7-1-26) x. Information regarding the relevant factors set forth in Subsection 401.03; and (3-24-22) xi. A proposed point of compliance, or points of compliance. (3-24-22) b. Within thirty (30) days of receipt of an application, the Department will issue a written notice to the mine operator indicating: (7-1-26) i. That the application is complete; or (3-24-22) ii. That the Department is rejecting the application as incomplete. In such a case, the Department will provide a list of deficiencies. Upon a determination that the application is incomplete, the Department will refund one-half (1/2) of the application fee. (7-1-26) c. The Department will establish the point(s) of compliance within one hundred eighty (180) days after receipt of a complete application unless the Department determines that additional time is necessary due to unusual circumstances. (7-1-26)
03. Setting the Point(s) of Compliance. The point(s) of compliance will be set as close as possible to the boundary of the mining area, taking into consideration the relevant factors set forth in Subsections 401.03.a. through 401.03.h., but in no event may the point(s) of compliance be within the boundary of the mining area. The mining area boundary means the outermost perimeter of the mining area (projected in the horizontal plane) as it would exist at the completion of the mining activity. The point(s) of compliance will be set so that, outside the mining area boundary, there is no impairment to current or projected future beneficial uses of groundwater and there is no violation of water quality standards applicable to any interconnected surface waters. The Department's determination regarding the point(s) of compliance will be based on an analysis and consideration of all relevant factors including, but not limited to: (7-1-26)
a. The hydrogeological characteristics of the mining area and surrounding land, including any dilution characteristics of the aquifer and any natural attenuation supported by site-specific data; (3-24-22) b. The concentration, volume, and physical and chemical characteristics of contaminants resulting from the mining activity, including the toxicity and persistence of the contaminants; (3-24-22) c. The quantity, quality, and direction of flow of groundwater underlying the mining area; (7-1-26) d. The proximity and withdrawal rates of current groundwater users; (7-1-26) e. A prediction of projected future beneficial uses; (3-24-22) f. The availability of alternative drinking water supplies; (3-24-22) g. The existing quality of the groundwater, including other sources of contamination and their cumulative effects on the groundwater; and (7-1-26) h. Public health, safety, and welfare effects. (3-24-22)
04. Groundwater Monitoring and Reporting. The Department will require groundwater monitoring and reporting whenever the Department sets the point(s) of compliance. The Department will not require groundwater monitoring that duplicates groundwater monitoring required by other state or federal agencies as long as the mine operator provides the data to the Department. (7-1-26)
a. A groundwater monitoring system required under Subsection 401.04 must be designed to: (7-1-26) i. Represent the quality of background groundwater that has not been affected by the mining activity; and (7-1-26)
ii. Represent the quality of groundwater passing the point(s) of compliance to determine compliance with groundwater quality standards or effectiveness of best management practices. (7-1-26)
b. When practicable, indicator monitoring wells or other devices may be required. Such indicator wells and other devices may not be used to determine compliance with the groundwater quality standards, but instead may be used to evaluate modeling results, predict the quality of groundwater at the point(s) of compliance, or determine the effectiveness of best management practices. (7-1-26)
c. All monitoring wells must be constructed (well depth, well screen size, well screen interval, gravel pack, etc.) and developed so that groundwater samples represent the quality of groundwater that is relevant to current and future beneficial uses. (7-1-26)
05. Coordination with Other State or Federal Agencies/Public Notice. Before setting the point(s) of compliance or requiring groundwater monitoring, the Department will coordinate with and seek recommendations from other state or federal agencies with regulatory authority over the mining activities. The Department may provide public notice and an opportunity for public comment prior to setting or changing the point(s) of compliance. The Department will issue a public notice after it sets the point(s) of compliance. (7-1-26)
06. Limitations. Section 401 addresses only those contaminants that naturally occur in the mining area groundwater or in the surrounding rock or soil and are present in concentrations above the natural background level as a result of mining activities. (7-1-26)
07. Application of Provisions. The provisions in Section 401 apply to new mining activities or to an expansion of existing mining activities. All consent orders, compliance schedules, and other agreements adopted or issued by the Department prior to July 1, 2009, pertaining to groundwater protection at mine sites will remain in full force and effect. (7-1-26)
08. Change in Point(s) of Compliance/Groundwater Monitoring. (7-1-26)
a. A change in the point(s) of compliance may be requested by the mine operator when there is a change in, or new information regarding, the mining activity or any of the factors set forth in Subsection 401.03. A change requested by the mine operator must include an identification of the new proposed point(s) of compliance, a description of the cause for the change, and any data supporting the change. The mine operator's request will be handled as an application submitted pursuant to Subsection 401.02.a. and will be subject to all other provisions of Section 401. (7-1-26)
b. The Department may initiate a change in the point(s) of compliance if there is a change in, or new information regarding, the mining activity or any of the factors set forth in Subsection 401.03, and the Department determines that the change is necessary to ensure there is no impairment to current or projected future beneficial uses of groundwater and no violation of water quality standards applicable to any interconnected surface waters. The Department will notify the mine operator in writing of the Department's intent to change the point(s) of compliance. The Department will make its final decision to change the point(s) of compliance within sixty (60) days of the notice to the mine operator unless the Department and the mine operator agree more time is necessary to make the decision. (7-1-26)
c. The Department may require additional or new groundwater monitoring or indicator wells when the Department changes the point(s) of compliance. The Department may also require additional or different
groundwater monitoring or indicator wells if the Department determines, based upon a change in or new information regarding the mining activity or any of the factors listed in Subsection 401.03, that the monitoring no longer meets the provisions in Subsection 401.04. The mine operator may also request a change in the monitoring. (7-1-26)
402. -- 999. (RESERVED)