Small Depressions on Indian Lands Guidance
Guidance for Evaluation of Small Depressions
Indian Lands Program
Office of Surface Mining
These guidelines are intended to provide Office of Surface Mining (OSM) staff and the coal industry with information about how small depressions will be evaluated and authorized for retention on surface coal mining operations on Indian Lands. It is clear the Act and regulations allow for small depressions in the reclamation landscape; however, there are several basic questions that are frequently asked regarding what constitutes a small depression. This guidance is presented as a series of questions and responses that are intended to clarify the Western Regional Coordinating Center's (WRCC's) interpretation and applicability of 30 CFR 816.102(h) to coal mines operating on Indian Lands. Western Region recognizes the importance of retention of small depressions on Indian Lands mines in the southwest. Among the benefits that small depressions provide are: playa restoration, moisture retention, wildlife enhancement, erosion control, and vegetation enhancement. In the arid and semiarid southwest, the moisture retention characteristics of small depressions are particularly valuable in supporting vegetation and wildlife diversity on reclaimed lands.
Authorization for small depressions in the reclamation landscape is provided in the Act at 515(b)(3) as part of the environmental protection performance standards:
"except as provided in subsection (c) with respect to all surface mining operations backfill, compact (where advisable to insure stability or to prevent leaching of toxic materials), and grade in order to restore the approximate original contour of the land with all highwalls, spoils piles, and depressions eliminated (unless small depressions are needed in order to retain moisture to assist revegetation or as otherwise authorized pursuant to this act): ----"(emphasis added)
The performance standards for small depressions are provided at 30 CFR 816.102(h):
"Small depressions may be constructed if they are needed to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation."
Additional regulatory support can be found at 30 CFR 701.5; 816.71(e)(4); 816.83(c)(3); 816.102(a)(2); and 816.102(h). Also preamble language at 48 FR 23358, 48 FR 23363, and 48 FR 44002 contains some regulatory guidance for evaluation of small depressions.
SMCRA, Regulations, and Preamble Language
Concerning Small Depressions
515(b) General performance standards shall be applicable to all surface coal mining and reclamation operations and shall require the operation as a minimum to:
. . . (3) except as provided in subsection (c) with respect to all surface coal mining operations backfill, compact (where advisable to insure stability or to prevent leaching of toxic materials), and grade in order to restore the approximate original contour of the land with all highwalls, spoil piles, and depressions eliminated (unless small depressions are needed in order to retain moisture to assist revegetation or as otherwise authorized pursuant to this Act)
701.5 Impoundments means all water, sediment, slurry or other liquid or semi-liquid holding structures and depressions, either naturally formed or artificially built
816.71(e)(4) No permanent impoundments are allowed on the completed fill. Small depressions may be allowed by the regulatory authority if they are needed to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation; and if they are not incompatible with the stability of the fill.
Coal Mine Waste
816.83(c)(3) No permanent impoundments shall be allowed on the completed refuse pile. Small depressions may be allowed by the regulatory authority if they are needed to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation, and if they are not incompatible with stability of the refuse pile.
Backfilling and Grading
816.102(a)(2) Eliminate all highwalls, spoil piles, and depressions, except as provided in Paragraph (h) (small depressions) and in Paragraph (k)(3)(iii) (previously mined highwalls) of this Section;
816.102(h) Small depressions may be constructed if they are needed to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation.
Backfilling and Grading Requirements:
5-24-83 Federal Register (48 FR 23358)
One commenter suggested replacing the section reference for small depressions in proposed § 816.102(b)(2)(i) with the language from § 816.102(h) that pertains to small depressions. The commenter offered no explanation for this suggested change.
The depressions that Section 515(b)(3) of the Act requires to be removed are those formed during the mining operation before any backfilling and grading of the spoil has been accomplished. They may be of any size and are not planned as part of the postmining land-use plan. The small depressions allowed to remain by the Act and § 816.102(h) are small depressions used for specific purposes and formed during the reclamation operation. OSM has retained the organization of these two paragraphs as set out in the proposed rule because to combine them would create a long and confusing paragraph.
Backfilling and Grading Requirements:
5-24-83 Federal Register (48 FR 23363)
Final § 816.102(h) states that small depressions may be constructed if they are needed to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation. The creation and enhancement of wildlife habitat was not included in the proposed rule.
One commenter advocated constructing small depressions to create and enhance wildlife habitat. It was suggested that this new use for small depressions be added to proposed § 816.102(g). OSM has accepted the comment that benefiting wildlife is a reasonable use of small depressions. Section 515(b)(3) of the Act allows small depressions as authorized pursuant to the Act. Section 515(b)(24) of the Act requires fish, wildlife, and related environmental values to be enhanced where practicable. OSM believes small depressions could, in certain cases, be a practicable means of benefiting wildlife and increasing wildlife habitat. The final rule reflects this position.
Another commenter described using depressions as a means of requiring less backfilling in the final cut of an area mine. A depression would be created between the sloped highwall and the last spoil ridge that would be terraced. The depression would undoubtedly collect water during some periods of the year. However, the Act, at Section 515(b)(3), does not allow depressions to circumvent the AOC restoration requirements. Also, the depressions described by the commenter would not qualify as small depressions under § 816.102(h). Depressions cannot substitute for fully backfilling the mining pit. Congress intended that depressions that would collect and store water be barred from the surface area unless permanent impoundments are approved (Senate Report 95-128, 95th Congress, 1st Session, 1977, p. 99). Therefore, the depressions described by the commenter are not allowable.
Permanent and Temporary Impoundments:
9-26-83 Federal Register (48 FR 44002)
Commenters made reference to OSM's proposed rules permitting certain small depressions after backfilling and grading (see 30 CFR 816.102(c)). The commenter questioned whether it was possible to treat a permanent impoundment that did not meet the design storm size requirements as a small depression, subject only to the § 816.102(c) requirements.
Section 816.102(c) provides a limited exception to the approximate original contour restoration requirements for small depressions. Small depressions are not expected to hold water and must be renegotiated. A small depression that is capable of holding water would be classified as an impoundment. Thus, it would not be possible for any impoundment to be treated only as a small depression. In order to allow a permanent impoundment, § 816.49, 816.56 and 816.133 or § 817.49, 817.56 and 817.133 must be satisfied.
Appendix B: Navajo Mine Criteria
Navajo Mine Permit
Section 12.3 (pages 12-7 and 12-8)
During the process of secondary grading, small depressions may be established on an opportunistic basis. These features will enhance post-mining topographic diversity and act as seasonal surface water collection sites. Small depressions will serve as wildlife enhancement features and micro-topographic niches for establishment of music and/or hydria plant species. Although these depressions will not have specific design criteria, they will be small enough that they will occur within the limits of the approved AOC. These small depressions will also meet the following specific criteria:
- Each depression or combination of directly adjacent depressions will be less than one acre foot total capacity,
- No depression will be deeper than 10 feet,
- All small depressions will be incised (below ground level),
- The maximum in slope for the small depression will be 6:1 and
- At bond release, small depression areas will be subject to vegetation sampling similar to any area within the bond release parcel.
Question: Do small depressions require regulatory approval?
Small depressions may occur inadvertently as the result of differential settling of backfilled materials, or they may be planned and constructed. The Federal regulations do not specifically require small depressions to be planned, designed, and approved as a part of the permit application process. However, OSM, as the regulatory authority for Indian Lands mines, must authorize (i.e. approve retention of) small depressions prior to bond release. It is anticipated that this authorization would occur during the routine contemporaneous inspections of the mine, although it could occur during bond release inspections.
Comments regarding proposed rule 816.102(a) and (b) published in the May 24, 1983, Federal Register (48 FR 23358) stated:
"The small depressions allowed to remain by the Act and 816.102(h) are small depressions used for specific purposes and formed during the reclamation operation."
In no case will the approval of inadvertent small depressions be allowed as a measure to minimize the amount of material that must be backfilled and graded to ensure proper drainage in a reclamation area.
Western Region strongly encourages applicants and permittees to define criteria for small depressions in their permit application package (PAP) so that both the operator and OSM will know what is required when final grading is completed (e.g., during a routine inspection). Western Region believes that it would be advantageous if the operator and OSM were to agree during the permitting process on general criteria for small depressions such as has been accomplished with the Navajo Mine team (see Appendix B). Approval of criteria is supported by the requirements of 30 CFR 780.18 (a) which state in part "each application shall contain a plan for reclamation . . . showing how the applicant will comply with . . . the environmental protection performance standards of the regulatory program," including the requirements for small depressions at 30 CFR 816.102(h). The alternative would be evaluation of small depressions during inspections after grading is completed. If unacceptable depressions were identified during the inspection, additional grading would be required.
Question: What general criteria should be considered when evaluating a small depression?
The following general criteria for small depressions can be gathered from the Act, regulations, and preamble language (see Appendix A.)
Small depressions must be authorized (i.e., allowed) by the regulatory authority.
Small depressions must be formed during the reclamation phase of the operation.
Small depressions must be used for specific purposes: to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation.
Small depressions must be revegetated (seeded)
Small depressions are a limited exception to the backfilling and grading requirement to eliminate all depressions, but they may not be used to circumvent the AOC restoration requirements. Depressions cannot substitute for fully backfilling the mining pit.
Small depressions are not permanent impoundments.
Small depressions are not expected to hold water as their primary purpose. However, small depressions may retain water to meet a specific purpose. An impoundment cannot be treated as a small depression. Depressions that collect and permanently store water are not permitted unless approved as permanent impoundments.
Question: What water retention properties are expected from small depressions and how do small depressions differ from impoundments?
The preamble discussions emphasize that the intended purpose of an impoundment is to collect and store (hold) water for an approved purpose. The Federal regulation at 30 CFR 816.49(b) for permanent impoundments, requires a showing that, among other things, water will be stored for a sufficient length of time to support the intended purpose of the permanent impoundment, generally to provide a water supply or other use that requires persistent water availability. (The water level will be sufficiently stable and be capable of supporting the intended use.)
Small depressions may collect and retain water for a time period, incidental to their intended purpose, which is to retain moisture, minimize erosion, create and enhance wildlife habitat, or assist revegetation. [30 CFR 816.102(h)] Unlike permanent impoundments, small depressions would properly hold water long enough to fulfill their prescribed purpose.
In general, impoundments are those structures that must comply with the regulations at 30 CFR 780.25, 816.46, and 816.49, while small depressions are not required to be designed under these regulations. Small depressions are incised and have no embankments.
Question: What sizes of small depressions are allowable?
There is no definition for small depressions at either 30 CFR 701 or 705. In addition, the minimum or maximum size of small depressions is not specifically addressed in the permanent program regulations at 816.102(h).
One decision (Appolo Fuels, Inc. vs. OSM, IBLA 93-309) from an Administrative Law Judge (ALJ) adds some clarification regarding size of small depressions. The ALJ found that the regulations did not establish a bright line measurement to define the size of small depressions and that if the depression can be shown to meet one of the purposes of 816.102, then they can be allowed to remain.
Neither the comments submitted during rule-making nor the small depression regulation itself specifically address the size or frequency question of small depressions in a reclamation landscape, but the general guidance indicates that they are allowed when the specific benefits at 816.102(h) are gained. The one clear objection is when excessive depression areas are proposed in an attempt to not fully backfill a pit.
Therefore, Western Region will not prescribe limits to the size or number of small depressions; however, each permit evaluation will determine, on a case-by-case basis, whether the depressions meet the intent of the regulation.
Question: Where can small depressions be located in the landscape and at what frequency?
In recent years, the use of machinery to imprint small depressions has been, for the most part, discontinued. This practice has been replaced by essentially leaving the reclaimed surface in a rough condition. However, the option to use imprinters, contour furrows, etc., is acceptable to Western Region. This type of small depressions can be used on a widespread basis since they will tend to fill over time and are not permanent features.
Small depressions will not be allowed in major drainage ways, but would either be evaluated as pool areas in the reclamation channel design or as a permanent impoundment. The frequency of occurrence of small depressions in the landscape will primarily be governed by the ability of the area to meet bond release success standards. If, for example, several small depressions were concentrated in an area and they were bare (i.e., no vegetation in the centers), the cumulative amount of bare area might prevent the area from meeting revegetation success standards.
Question: What is the relationship between a small depression and a wetland?
The regulations at 30 CFR 816.102(h) allow small depressions to be constructed for the purposes of creating or enhancing wildlife habitat. Under this provision, wetlands may be created and retained on reclaimed lands. Small depression wetlands may occur as wildlife enhancement features within any postmining land use if authorized by OSM. For further guidance on wetlands please see OSM Directive TSR-14, Construction of Wetlands as a Postmining Land Use.
Question: Can small depressions be bare of vegetation or must they be "revegetated"?
Small depressions are expected to be revegetated, which means the area within the small depression must be seeded (the small depression would be seeded along with the surrounding reclamation area). Western Region recognizes that some small depressions (or parts of depressions) may, over time, become devoid of vegetation (primarily due to submergence) and result in bare areas on the reclaimed surface. The reclaimed areas that contain small depressions will be subject to vegetation success standards and as such, if the small depression is large (and bare of vegetation) or if the area under evaluation contains several small depressions that are bare, the lack of vegetation could result in a failure to demonstrate revegetation success and delay bond release. Western Region recommends that operators consider seeding the small depressions with species adapted to specific conditions of the site (e.g., mesic, salt tolerant species) in order to enhance vegetative success.