Code of Maine Rules
06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION
096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL
Chapter 378 - VARIANCE CRITERIA FOR THE EXCAVATION OF ROCK, BORROW, TOPSOIL, CLAY OR SILT AND PERFORMANCE STANDARDS FOR THE STORAGE OF PETROLEUM PRODUCTS
Section 096-378-3 - Submissions

Universal Citation: 06 ME Code Rules § 096-378-3

Current through 2024-38, September 18, 2024

This section outlines submission requirements related to the variance approval standards described in Section 2, above.

A. Separation of less than five feet from seasonal high water table. If any part of the excavation is to be less than five feet from the seasonal high water table, the following submissions are required.

(1) A plan of the site showing the locations of test pits, borings, monitoring wells, seismic lines, or other subsurface investigations undertaken to establish the elevation of the seasonal high water table. If these investigations have intercepted the seasonal high water table, or otherwise provide evidence of its location, the plan must show the elevations of the seasonal high water table at those points. The contours of the seasonal high water table must be shown throughout the areas in which excavation is proposed to be less than five feet from the seasonal high water table.

(2) Logs and other supporting documentation of the subsurface investigations conducted to establish the elevation of the seasonal high water table.

(3) A plan for regular monitoring of water table elevations at representative locations within the excavation and in the immediate vicinity, and regular reporting of data to the department, at intervals to be determined by the department. During each year of pit operation, water table elevations must be monitored biweekly during April, May, and June, and once in September, December, and March. At least one year of background water level data must be obtained from these wells prior to any excavation to within less than five feet of the seasonal high water table.

(4) The department reserves the right to require more or less frequent monitoring of water table elevations if, in the opinion of the department, such monitoring is necessary to evaluate the impact of the excavation on water supply wells or protected natural resources. Cases in which more or less monitoring might be required include the following:

(a) The department may, at its discretion, require less frequent monitoring of water table elevation if it determines that a statistical analysis of the data shows no evidence of unanticipated changes in water table elevation.

(b) The department may require resumption of the original frequency, or substitute another frequency, in the event of evidence of declining water quality in areas impacted by the excavation or changes in water table elevation not anticipated in the study submitted to meet the requirements of this variance.

(c) The use of pre-existing data shall be subject to approval by the department The applicant shall discuss the manner and time in which the data were acquired, the analytical or investigative methods used and any other factors relevant to the quality and applicability of the data.

B. Excavation into groundwater. If any part of the proposed excavation will be below the elevation of the seasonal high water table, the following submissions are required in addition to the submissions required under subsection A above.

(1) A plan of the site showing the estimated post-development water table contours. This plan must show, at a minimum, all areas in which the elevation of the water table is likely to be impacted by the development, and must specifically address the potential impact on any pre-development water supply wells or protected natural resources in the vicinity of the excavation.

(2) Measurements of the safe yield and water quality of any water supply well within that area in which the elevation of the water table will be impacted by the development. For the purposes of this rule, "safe yield" is defined as the amount of water which can be withdrawn from a well without producing adverse effects on the quality or quantity of water available to that well, protected natural resources, or other users of groundwater.

(3) Provisions for regular analysis of the water table data for the site, for the purpose of comparing the data to the estimated post-development water table. This analysis must be submitted to the department on an annual basis, unless another interval is specifically required by the department, until the department determines that reclamation of the excavation is complete.

(4) Provisions for quarterly measurement of groundwater quality in the vicinity of the excavation. Water quality of upgradient and downgradient wells must be measured for at least the following parameters: iron, manganese, extractable petroleum hydrocarbons (EPH), volatile petroleum hydrocarbons (VPH), pH, and specific conductivity. If explosives are used in the excavation, the applicant must also monitor levels of nitrate or other applicable parameters which are likely residues of explosives. At least one year of background data must be obtained from these wells prior to any excavation in the area proposed for excavation below the water table.

(5) The department reserves the right to require more or less monitoring parameters if, in the opinion of the department, such monitoring is necessary to evaluate the impact of the excavation on water supply wells or protected natural resources. Cases in which more or less monitoring might be required include the following:

(a) The Department may, at its discretion, reduce the list of monitored parameters if it determines that a statistical analysis of the data shows no evidence of declining groundwater quality.

(b) Cases in which such additional parameters might be required include, but are not limited to: evidence of declining water quality in areas impacted by the excavation; proximity of the excavation to a known contaminant source, such as a landfill, hazardous waste site, engineered septic system, or waste discharge site.

C. Reclamation requirements for excavation activities conducted below the seasonal high water table. In the event of excavation below the seasonal high water table, the operator of the mining activity must reclaim the affected area as a pond according to the following standards.

(1) The water supply to the pond must be sufficient to maintain the approximate water elevation specified in the design of the pond under normal circumstances. The bottom of the pond must be undulating to provide a variety of water depths.

(2) In order to provide suitable conditions for safety and egress, shallow areas of less than 3 feet in water depth must exist along the shoreline. These areas must be graded to a slope no steeper than 4H to 1V.

(3) To increase the pond's productivity, the shoreline must be irregular in shape.

(4) A pond may not be smaller than one-half acre.

D. Externally drained pits. If any area of an excavation or quarry regulated under 38 M.R.S.A. §490-B or 38 M.R.S.A. §490-X will be externally drained at any time during the development, operation, or use of the site, then that portion of the operation must have a stormwater management plan for the control and treatment of runoff. The following standards and submission requirements must be met.

(1) Site Plan. Submit a topographic plan of the operation showing all areas disturbed or developed as a result of the operation, including all buildings, processing facilities, stormwater management structures, excavation areas, roads, stockpile areas, and existing and proposed contours. The plan must clearly indicate by boundary line the portion(s) of the operation that will be externally drained.

(2) Basic standard for erosion control, maintenance, and housekeeping. Externally drained excavations or quarries must meet the basic standard identified at 06-096 CMR 500.4(A) and the submission requirements identified at 06-096 CMR 500.8(C).

(3) General standards for stormwater quality. If the externally drained excavation or quarry is not located in the direct watershed of any lake, then the excavation or quarry must meet the general standard identified at 06-096 CMR 500.4(B)(2)) and the submission requirements identified at 06-096 CMR 500.8(D). For purposes of calculating volumes and sizing buffers for this standard, areas exposed for mining or stockpiling of rock, gravel, borrow, topsoil, clay, or silt shall be considered impervious area.

(4) Phosphorus standard for stormwater quality. If the externally drained excavation or quarry is located in the direct watershed of any lake, then that portion must meet the phosphorus standard identified at 06-096 CMR 500.4(C) and the submission requirements identified at 06-096 CMR 500.8(D). For purposes of determining phosphorus export for the phosphorus standard, areas exposed for mining or stockpiling of rock, gravel, borrow, topsoil, clay, or silt shall have a phosphorus export equal to that of pavement unless the Department approves alternate export rates.

(5) Urban impaired stream standard. If the externally drained area of an excavation or quarry is three acres or more of impervious area and is located in the watershed of an urban-impaired stream or stream segment listed in 06-096 CMR 502, Appendix B, then the excavation or quarry must meet the urban-impaired stream standard identified at 06-096 CMR 500.4(D). For purposes of determining the compensation fees and mitigation credits needed for the urban impaired stream standard, areas exposed for mining or stockpiling of rock, gravel, borrow, topsoil, clay, or silt shall be considered non-roof impervious area. Reclamation of existing and proposed mining areas regulated under 38 M.R.S.A. §490-B or 38 M.R.S.A. §490-X may not be used as compensation credit for meeting the urban-impaired stream standard.

(6) Flooding standard for stormwater quantity. Externally drained excavations or quarries, must meet the flooding standard identified in 06-096 CMR 500.4.D for both site operation and post-reclamation conditions. The following information must be provided to the department.

(a) A narrative describing the operation layout, the pre-excavation hydrology, the hydrology changes resulting during operations, the hydrology changes after reclamation, and the stormwater management measures to be put in place to prevent stormwater quantity impacts on and off the site.

(b) A pre-excavation drainage plan, at a scale and contour interval to be determined by the department, showing drainage subcatchment boundaries, flow paths, reaches, storage areas, cover type boundaries, and soil type boundaries.

(c) A site operation drainage plan, at a scale and contour interval to be determined by the department, showing drainage subcatchment boundaries, flow paths, reaches, storage areas, cover type boundaries, and soil type boundaries.

(d) A post-reclamation drainage plan, at a scale and contour interval to be determined by the department, showing drainage subcatchment boundaries, flow paths, reaches, storage areas, cover type boundaries, and soil type boundaries.

(e) Pre-excavation runoff rate and runoff volume calculations for the 2-year, 10-year, and 25-year storms, including runoff curve number computations and time-of-concentration calculations for each drainage subcatchment; a reach description and routing analysis for each drainage conveyance; and pond description and pond routing analysis for each runoff storage structure.

(f) Site operation runoff rate and runoff volume calculations for the 2-year, 10-year, and 25-year storms, including runoff curve number computations and time-of-concentration calculations for each drainage subcatchment; a reach description and routing analysis for each drainage conveyance; and pond description and pond routing analysis for each runoff storage structure.

(g) Post-reclamation runoff rate and runoff volume calculations for the 2-year, 10-year, and 25-year storms, including runoff curve number computations and time-of-concentration calculations for each drainage subcatchment; a reach description and routing analysis for each drainage conveyance; and pond description and pond routing analysis for each runoff storage structure.

NOTE: Acceptable stormwater methodologies and models include "TR-20 Computer Program for Project Formulation - Hydrology," Second Edition, U. S. Department of Agriculture, Soil Conservation Service (March 1986); "TR-55 Urban Hydrology for Small Watersheds," Second Edition, U. S. Department of Agriculture, Soil Conservation Service (June 1986); "WIN TR-55 2003.00.24 Microcomputer Program" (January 12, 2003); and "HEC-HMS Flood Hydrology Package," U. S. Army Corps of Engineers (January 2001). Any methodology or model other than those listed must have prior approval from the department.

(h) A detail sheet showing the plan and cross section views for each proposed stormwater management basin, pond, or other storage structure which identifies the permanent pool elevation (if any) and the peak water levels in the basin, pond, or structure due to runoff from the 2-year, 10-year, and 25-year, 24-hour storms.

(i) A detail and specifications sheet for each basin's, pond's, or storage structure's embankment construction, impoundment construction, outlet control structure fabrication and installation, and emergency spillway construction.

(j) Logs for soil borings or test pits done at the location of each proposed stormwater management basin, pond, or other storage structure.

NOTE: Siting and design specifications for stormwater management basins and ponds can be found in 06-096 CMR 500 Appendix E and in Volume III of the department's manual Stormwater Management for Maine (January 2006).

(7) Easements and covenants. If the externally drained portion of the operation will require specific off-site areas for the control, disposal, or treatment of stormwater runoff, then these off-site areas must be protected from alteration through easements or covenants in accordance with the standards in 06-096 CMR 500.4(F).

(8) Management of stormwater discharges. The discharge of concentrated runoff from stormwater management basins or ponds must be to areas that have received concentrated flows before development of the operation. If an operation must discharge flows through an open-channel or pipe to any point that is not an open channel, an inlet to a storm drain system, or a natural or man-made impoundment, then the discharge will only be allowed if flow can be converted to sheet flow through use of a properly designed level spreader meeting the criteria in 06-096 CMR 500.5(A).

(9) Plans and calculations for the proposed stormwater management system must be signed by and bear the sealed of a professional engineer registered in Maine and qualified to undertake the design.

(10) Nothing in 06-096 CMR 378.3(D) may be construed to supersede or replace the Erosion and Sedimentation Control Standard established in 38 M.R.S.A. §490-D(8).

E. Larger working pits. The financial assurance provisions below apply to any excavations with a working pit larger than 10 acres. Financial assurance is designed to ensure that the operator satisfactorily meets all requirements of 38 M.R.S.A. §490-D and 38 M.R.S.A. §490-Z. Financial assurance must cover the affected land.

(1) The amount of financial assurance required is determined by the department. The type of financial assurance must be as described under this rule. The amount of financial assurance must be, at a minimum, the estimated cost to a third party for completing the reclamation for all disturbed areas, and all areas expected to be disturbed within the upcoming year.

(2) The permittee shall pay into a reclamation fund established for the benefit of the department as follows.

(a) The reclamation fund must be funded by the permittee through cash deposits, letter of credit, or surety.

(b) The initial deposit for reclamation costs, identified above, must be made prior to site disturbance. Subsequent payments must be made on or prior to the next subsequent anniversary date of permit issuance, and annually thereafter.

(c) Annual deposits or increases in the required reclamation fund amount must be made from the beginning of the operation to the end of the operation and until the successful completion of all reclamation activities. Without limitations changes in the amount in the fund may be required by the department due to modifications of the permit, changed financial conditions or site conditions, technology changes, inflation, anticipated changes in mining activity and corrective action, and reclamation. The permittee shall annually report to the department, subject to the department's approval, an estimate of cost changes as provided in this rule. The permit remains in effect only if all required deposits or increases are made within 30 days of the due date provided in this rule. The obligation to make deposits or adjust the letter of credit or bond amount ceases only upon approval from the department.

(d) When computing the annual inflation adjustment for reclamation, the department and the permittee must use the Implicit Price Deflator for Gross National Product as published by the U.S. Department of Commerce in "Survey of Current Business".

(e) The department may, at its discretion, grant approval for the withdrawal by the permittee of portions of the reclamation fund upon the permittee's verification that the sums authorized have been used solely for their intended, and department-authorized, purposes provided the remaining funds are sufficient to cover expenses required by this rule. In any event, 25% of the total financial assurance obligations must be retained in the trust fund until all reclamation is completed.

(f) If a permit is suspended, revoked, or not renewed, the permittee must continue to make deposits according to this rule.

(g) The financial assurance cost estimates must be made in U.S. dollars in accordance with established estimating practices and must not incorporate any salvage value that may be realized by the sale of materials, wastes, site structures or equipment, land, or other assets associated with the site.

(h) If a permittee fails to post required financial assurance, the department must issue a notice of violation to the permittee.

(3) The following requirements apply to all financial institutions issuing a letter of credit under this rule.

(a) The letter of credit must be unconditional, irrevocable, issued for a period of at least one year, and otherwise in a form satisfactory to the department. At least 90 days before the expiration date, the financial institution issuing the letter of credit must notify the permittee and the department if the letter of credit will not be renewed for an additional one year period, and the letter of credit must so provide. If the permittee is unable to obtain a letter of credit that complies with this rule prior to 45 days before the expiration of the current letter of credit, the department shall immediately draw all funds under the letter of credit and deposit those in the reclamation fund. The permittee shall also take all other measures necessary to maintain the letter of credit as provided herein and to assure such letters do not expire unless replaced with another duly qualified letter.

(b) The letter of credit must be issued so as to be drawn upon unconditionally by the department to meet the terms of the trust fund or otherwise at the call of the department.

(c) The financial institution issuing the letter of credit shall meet the following financial criteria, and must be reviewed no less often than annually by the department:

(i) It has assets of not less than $50 million.

(ii) It has Tier 1 leverage capital, as defined by its primary federal regulator, of not less than 6% of total assets.

(iii) Its unsecured long-term debt, if rated, is rated A or better by Moody's Investor Service or A or better by Standard and Poor's.

(iv) Its parent company, if any, has Tier 1 leverage capital, as defined by its primary federal regulator, of not less than 5% of total assets on a consolidated basis.

(v) Its parent company's unsecured long-term debt, if rated, is rated Baa or better by Moody's Investors Service or BBB or better by Standard and Poors.

(vii) The proposed letter of credit must be submitted to the department for review and approval.

(viii) In the event the department delivers to the financial institution a certificate so requesting and signed by the department, the financial institution shall draw down the full amount available under the letter of credit specified in the certificate and shall deposit to the department's reclamation fund the amount drawn down.

In the event that an issuer of a letter of credit ever fails to meet these criteria, the department shall immediately order the permittee to replace it with a properly qualifying letter of credit, failing which the department shall immediately call the letter of credit.

(4) The following requirements apply to all surety bonds provided under this rule.

(a) The bond must be issued for a period of at least one year and in a form acceptable to the department. At least 90 days before the expiration date, the surety company issuing the bond must notify the permittee and the department if the bond will not be renewed for an additional one year period. The text of the bond must include a provision for notice of cancellation. If the bond will not be renewed, the permittee shall immediately replace it.

(b) The bond must be issued so as to be drawn upon unconditionally by the department.

(d) The surety issuing the bond must have its unsecured long-term debt rated "A" or better by Standard and Poors or "A" or better by Moody's Investor Service.

(e) The department will not accept the bond of a surety company which has failed or delayed in making payments on a forfeited surety bond.

(f) The proposed bond must be submitted to the department for review and approval.

(g) In the event that an issuer of a bond ever fails to meet these requirements, the permittee must replace it with a properly qualifying surety.

(h) In the event the department delivers to the surety company a certificate so requesting and signed by the department, the surety company must pay the full amount available under the bond specified in the certificate and deposit that sum to the department's reclamation fund.

(5) The following requirements apply when releasing financial assurance.

(a) When requesting close-out or release of financial assurance, the permittee must notify the department. The department shall make an inspection of the area, and if it finds that reclamation has been properly completed, in accordance with the requirements of these rules, applicable laws and the terms and conditions of the permittee's permit, it must notify the permittee.

(b) When the department makes a determination to release funds, it must notify the financial institution or surety company and the permittee in writing of the decision. At that time, the department must supply the financial institution or surety company and permittee with written approval to transfer the excess funds or to close the account. The department does not release the permittee from any reclamation or corrective action requirements or third party liability as a result of releasing any funds.

(c) If at any time the department finds that reclamation of the affected area is not proceeding in accordance with these rules, applicable laws and the permit, the department under the authority of 38 M.R.S.A. §490 may initiate forfeiture proceedings against the fund filed by permittee.

F. Side slopes steeper than 2.5H to 1V. These requirements apply to all externally drained pits. They may apply to internally drained pits if the department determines that there is a reasonable possibility of adverse impact on adjacent properties or protected natural resources due to failure of a slope steeper than 2.5-to-1. The slope stability analysis must consist of the following components.

(1) A detail sheet showing the cross section of the slope proposed to be graded to a slope steeper than 2.5H to 1V. The cross section must show the slope's soil stratigraphy (i.e., the different soil layers in the slope), the location of springs or seeps, and the location of any perched water tables.

(2) For each soil layer, a description of the soil (e.g. fine sand or coarse gravel), the thickness of the soil layer, the soil unit weight, if angle of internal friction (if a granular soil), and the soil cohesive shear strength (if a cohesive soil).

(3) The calculations for the slope stability analysis must show the slope's safety factor against failure.

(4) Photographs showing the existing condition of the slope.

If the department determines that there is not a reasonable possibility of adverse impact on adjacent properties or protected natural resources due to failure of a slope steeper than 2.5-to-1 in an internally drained pit, the applicant shall notify the department and include in this notification a drawing showing the location of the proposed steeper slopes and a narrative describing how those slopes will be stabilized.

NOTE: In most cases the slope will have only one or two soil layers. The applicant can obtain values for unit weight, angle of internal friction, and cohesive shear strength from laboratory tests or from data published in geotechnical textbook design manuals.

NOTE: The applicant can do the analysis by hand calculation, by computer, or (for limited cases) by using published stability charts. For analyses using soil properties obtained from laboratory tests, the slope factor of safety should be greater than 1.10. For analyses using soil properties obtained from general data in reference books, the slope factor of safety should be greater than 1.25.

G. Excavating closer than 100 feet to a public road. If any part of the excavation will be less than 100 feet to a public road, the following information must be submitted to support the variance application.

(1) A plan showing the location of the existing slope, the road and its associated right-of-way.

(2) Evidence that adequate provisions for safety and visual screening will be made and maintained, if applicable.

(3) Photographs showing the condition of the existing natural buffer between the public road and the excavation.

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

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