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Applicability of 327 IAC 15-5

About the Construction Stormwater General Permit

The Construction Stormwater General Permit (CSGP) applies to all "construction activity" that results in the disturbances of one (1) acre or more of land area. Areas smaller than one (1) acre are also regulated under the CSGP if the project is part of a "larger common plan of development or sale".

Construction Activity means land-disturbing activities and land-disturbing activities associated with the construction of infrastructure and structures. This term does not include routine ditch or road maintenance or minor landscaping projects.

Land-Disturbing Activity means any manmade change of the land surface, including removing vegetative cover that exposes the underlying soil, excavating, filling, transporting, and grading.

A "Larger Common Plan of Development or Sale" means a plan, undertaken by a single project site owner or a group of project site owners acting in concert, to offer lots for sale or lease; where such land is contiguous, or is known, designated, purchased or advertised as a common unit or by a common name, such land shall be presumed as being offered for sale or lease as part of a larger common plan. The term also includes phased or other construction activity by a single entity for its own use".

Land Disturbance Calculation

Under the CSGP, projects are regulated where land disturbance is projected to be greater than or equal to one (1) acre. The land disturbance must be calculated for all proposed land-disturbing activities that will be associated with a project site. Land disturbance includes grading, soil disposal, and stockpiling that exposes soil material to stormwater. Activities associated with land disturbance include grading, the installation of infrastructure (i.e. roads, stormwater drainage systems, etc.), utility work, and construction within developments and on individual building lots.

Land disturbance is the primary factor that should be utilized to determine whether a construction/land-disturbing activity will require compliance with the CSGP. While this determination can be projected by the project site owner, there are special circumstances that apply to the CSGP for multi-lot projects. Below are guidelines listed in the CSGP that will assist in calculating the land disturbance.

The project site owner should estimate all land-disturbing activities that will be associated with the overall project by adding the total projected area of land disturbance including all site improvements, such as roads, utilities and/or common areas and expected land disturbance for each individual lot based on the criteria below:

Multi-lot Projects:

  • Single Family Residential Lots:
    • Size of the lot is one half (0.5) acre or more - the land disturbance is assumed to be one half (0.5) acre.
    • Size of the lot is less than one half (0.5) acre - the land disturbance is assumed to be the actual size of the lot.
  • Commercial, Industrial, and multi-family dwellings: land disturbance on each individual lot is estimated to be:
    • To estimate the lot size for purposes of initial determinations of disturbance use the size of the lot.

Once each individual lot is developed, a minimum of one (1) acre disturbed must be used for each lot.  To further clarify, all out lots associated with a multi-lot commercial project must obtain their own permit coverage regardless of lot size. This determination has been made based on the overall development is a larger common plan of development.

Requirements Associated with Lots within a Permitted Project Site

Permit Coverage:

For lots within a larger permitted site that are less than one (1) acre, the individual lot operator/builder (Residential Lot) is not required to submit his/her own Notice of Intent. However, the individual lot operator/builder (Residential Lot) may choose to submit a Notice of Intent (NOI) for the activities that will be performed at the project site. The regulating entity may also require permit coverage be obtained for individual lots.

Development of a Stormwater Pollution Prevention Plan:

The overall developer of a project site that has obtained permit

For lots within a larger permitted site that are one (1) acre or more, the individual lot operator/builder (Residential Lot) or the Project Site Owner (Commercial, Industrial, or Multi-Family Lot) may be required to file for a separate permit.

The Rule assumes that land disturbance associated with a one (1) acre or more single-family residential lot will only disturb 0.5 acre. Therefore, the builder/lot operator on a single-family residential lot within a permitted project site does not need to submit a separate construction/stormwater pollution prevention plan (SWP3) or a Notice of Intent. However, if during a site inspection it is determined that land disturbance has exceeded one acre and the operations occurring at the site are out of compliance, the agency representative may require the individual lot owner to file a SWP3 and a Notice of Intent. This decision will be based on the conditions and compliance level associated with the individual lot in question.

For lots that are one acre or more, land disturbance is pre-determined to be one acre or more. Therefore, the Project Site Owner of a commercial, industrial, or multi-family lot of one (1) acre or more must always file their own construction/stormwater pollution prevention plan (SWP3) and Notice of Intent.

Applicability of Specific Project Types and Operations

Following is a list of project types and operations and how the Rule applies to each activity:

Strip Developments

A strip development is defined as a multi-lot project that fronts on an existing road. A strip development is considered one Project Site. These projects are subject to the Rule as must comply, provided the projected combined land disturbance is less than one acre and is not part of a larger common plan of development or sale.

Strip developments may or may not include land-disturbing activities associated with grading or the installation of infrastructure. Strip developments that include initial grading and/or the installation of infrastructure must include the projected land disturbance for these operations plus the projected land disturbance for each lot. Strip development that will not require any initial grading or installation of infrastructure are still required to comply with the Rule, provided that the projected land disturbance of each individual lot combined is one acre or more. The Rule clarifies calculation of land disturbance on each individual lot by utilizing the information contained in the Land Disturbance Section of this manual.

Single Family Residences

A single-family residential dwelling that is not part of a larger common plan of development or sale is excluded from filing a Construction Plan and a notice of intent if land disturbance is less than five acres.

Land disturbance for single family residential lots is limited to those activities associated with construction of a dwelling/garage, driveways, septic system, and others essential to the residence.  Land-disturbing activities that are not considered essential include, but are not limited to ponds, out buildings, etc. These types of activities will require submittal of a construction plan and permit based on the one-acre land disturbance threshold.

It was determined that these stand-alone projects are typically not a significant threat to water quality or the discharge of pollutants. It is important to note that these projects are not exempt from the Rule, but only from filing the Construction Plan and the Notice of Intent. The individual lot operator/owner must comply with provisions of the Rule. These include 327 IAC 15-5-7(b) (1-5), 15-5-7(b) (10), 15-5-7(b) (17), 15-5-7(b) (19), and 15-5-7(b) (20). These citations can be located at 327 IAC 15-5-7.

Off-site Construction Activities that Provide Services to a Project

Many projects require the construction or installation of special services for the project. These activities include, but are not limited to, the construction of road extensions, storm/sanitary sewers, water, and other utilities. These activities are required to be permitted under this Rule. The Construction Plan for the overall project should include off-site activities if the Project Site Owner is required to construct or manage the construction of these activities. If this is an unknown requirement at the time of initial Plan/Notice of Intent submittal, the Project Site Owner can amend the plan/Notice of Intent for activities of less than one acre. However, if the activity is one acre or more, the Project Site Owner shall develop and submit a separate Construction Plan and Notice of Intent. This information should be submitted in accordance with procedures as required by the Rule.

In some instances a local governmental entity or utility will construct, manage, and extend these services to the development or project area. In these situations, the governmental entity or utility will be directing the operations associated with the construction and will be required to develop and submit a Construction Plan and a Notice of Intent, provided the construction/land-disturbing activities are one acre or more.

Gas and Oil Exploration

The United States Environmental Protection Agency has excluded gas and oil exploration from the federal storm water regulations. This exclusion includes storm water run-off at oil and gas exploration, production, processing and treatment operations and transmission facilities where the run-off consists entirely of flows from conveyances such as pipes and ditches for rainwater collection, provided that the run-off is not contaminated by contact with raw materials or wastes. Indiana also recognizes this exclusion. However, this exclusion only applies to NPDES permitting. Activities (land disturbance) which occurs within the local governmental agencies, including Municipal Separate Storm Sewer Systems (MS4s) may be required to obtain permit coverage for the planned land disturbance as required by a local ordinance or other regulatory mechanism.

To determine if these activities are subject to the Rule should be based on the projected land disturbance.

Agricultural Activities / Operations

Requirements of the Rule do not apply to persons involved in agricultural land-disturbing activities. However, the definition of the agricultural land-disturbing activity does not include the construction of:

  • Barns
  • Out Buildings
  • Roads Associated with Infrastructure
    • Applies primarily to road that are being constructed to provide access to a facility, barn, out building, etc.
    • Farm lanes are not subject to the rule or used in the land disturbance calculation if it is being used to access a crop field or pasture.
  • Waste Lagoons and Facilities
  • Lakes and Ponds
  • Wetlands (constructed)
  • Other Infrastructure.

Land disturbance associated with the construction of these facilities are required to comply with 327 IAC 15-5. Agricultural activities that are exempt include tillage, planting, cultivation, harvesting, and operations for the production of agricultural, nursery, or vegetative crops. The exemption also applies to pasture renovation and establishment, construction of agricultural conservation practices, and the installation of drainage tile. Agricultural conservation practices include waterways, sediment basins, terraces, water and sediment control basins (WASCOB), and grade stabilization structures.

Forest Harvesting Operations

The Rule identifies forest harvesting operations as being exempt from the Rule. Harvesting operations include the actual area where the forest product is being cut, including skid roads. However, specific operations are not considered exempt and must be considered when estimating land disturbance. These operations include staging areas, access roads, and haul roads.

Any forest harvesting activity that is being conducted in preparation for land development, construction of roads, or other facilities is not considered exempt. These projects are subject to the Rule provided the land disturbance is projected to be one acre or more.

Coal Mining

A Rule 5 permit is not required for these operations. Storm water discharges from coal mine operations and coal mine reclamation areas are regulated by IDEM under a Rule 7 (327 IAC 15-7) permit and by permits issued through the Indiana Department of Natural Resources, Division of Reclamation. The Division of Reclamation also regulates shale mining.

Sand, Gravel, Dimensional Stone, or Crushed Stone Quarries

Mining activities may be regulated by IDEM under a Rule 6 (327 IAC 15-6) and/or a Rule 12 (327 IAC 15-12) permit. Rule 5 permits are required for the removal of overburden from new facilities or for the expansion of a facility this is not permitted under Rule 6.

Municipal Solid Waste Landfills or Landfills Certified for Closure

The following are not required to file for a General Permit under Rule 5:

  • Landfills that have been issued a certification of closure under 329 IAC 10.
  • Municipal solid waste landfills that are accepting waste pursuant to a permit issued by the department under 329 IAC 10 that contains equivalent storm water requirements, including the expansion of landfill boundaries and construction of new cells either within or outside the original solid waste permit boundary.

If it is determined that a project meets the applicability requirements of the Rule, the project site owner is required to obtain a General Permit prior to the initiation of any land-disturbing activities. The procedure for obtaining this permit is outlined in Step-by-Step Process for Compliance with 327 IAC 15-5.

Additional Information

For more information regarding the applicability requirements for 327 IAC 15-5, please contact the IDEM Storm Water Permits Coordinator.

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