Idaho Stormwater Management
Idaho State Overview
The State of Idaho and the Idaho Department of Environmental Quality (IDEQ) administer the Federal Construction General Permit (CGP) for stormwater discharges associated with construction activities. Such discharges define the runoff of any pollutants into waters of the United States (Idaho) from areas where land disturbing activities (clearing, grading or excavation) occur, or where construction materials or equipment are located. The EPA expects that compliance with the conditions of this permit will result in stormwater discharges that adhere to Federal water quality standards. This permit authorizes the discharging of stormwater runoff from construction sites where:
(1) Land disturbing activities are equal to, or greater than one (1) acre of total land.
(2) Construction activities involve less than one (1) acre of total land area, but are part of a common plan of development or sale equal to or greater than one (1) acre of land.
(3) Your project is located in an areas where EPA is the permitting authority.
*Permit number IDR120000, The Federal Construction General Permit, authorizes coverage for stormwater discharges within Idaho, except Indian country. Excluding Duck Valley Reservation Lands, Indian country within the State of Idaho is covered under permit number IDR120001.
(4) As designated by the Environmental Protection Agency (EPA), Stormwater discharges including stormwater runoff, snowmelt runoff, and surface runoff and drainage associated with construction activities.
The State of Idaho and the Idaho Department of Environmental Quality (IDEQ) administer the Federal Construction General Permit (CGP) for stormwater discharges associated with construction activities. Such discharges define the runoff of any pollutants into waters of the United States (Idaho) from areas where land disturbing activities (clearing, grading or excavation) occur, or where construction materials or equipment are located. The EPA expects that compliance with the conditions of this permit will result in stormwater discharges that adhere to Federal water quality standards. This permit authorizes the discharging of stormwater runoff from construction sites where:
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EPA Developing Your SWPPP Guide
Federal CGP Appendix A - Definitions
Federal CGP Appendix B - Areas of Permit Coverage
Federal CGP Appendix C - Waivers
Federal CGP Appendix D - Endangered Species Reqs
Federal CGP Appendix E - Historic Properties Reqs
Federal CGP Appendix F - Tier 3 Tier 2 Tier 2.5 Waters
Federal CGP Appendix G - Buffer Requirements
Federal CGP Appendix H - Storm Frequencies
Federal CGP Appendix I - Standard Permit Conditions
Federal CGP Appendix J - Notice of Intent (NOI) Form and Instructions
Federal CGP Appendix K - Notice of Termination (NOT) Form and Instructions
Federal CGP Appendix L - Request for Chemical Treatment
Federal CGP Appendix by Region
Federal CGP Fact Sheet
Federal CGP Low Erosivity Waiver Certification
Federal CGP NOI Deadlines Chart
Federal CGP Pre-publication Version of the Federal Register Notice
Federal CGP Stabilization Deadlines
Federal Construction General Permit (CGP)
EPA - Stormwater Phase II Final Rule - Construction Rainfall Erosivity Waiver
Federal Water Pollution Control Act (Clean Water Act)
Federal CGP Excerpt of Changes from Proposal to Final Modification
Federal CGP Register Notice for CGP
Federal MSGP Appendix A - Definitions, Abbreviations, and Acronyms (for the purposes of this permit)
Federal MSGP Appendix B - Standard Permit Conditions
Federal MSGP Appendix C - Permit Areas Eligible for Coverage
Federal MSGP Appendix D - Facilities and Activities Covered
Federal MSGP Appendix E – Procedures Related to Endangered Species Protection
Federal MSGP Appendix F - Procedures Relating to Historic Properties Preservation
Federal MSGP Appendix G - Notice of Intent (NOI) Form
Federal MSGP Appendix H - Notice of Termination (NOT) Form
Federal MSGP Appendix I - Annual Report Form
Federal MSGP Appendix J - Calculating Hardness in Freshwater Receiving Waters for Hardness Dependent Metals
Federal MSGP Appendix K - No Exposure Certification Form
Federal MSGP Appendix L - List of Tier 3, Tier 2, and Tier 2.5 Waters
Federal MSGP Appendix M - Discharge Monitoring Report (DMR) Form
Federal MSGP Appendix N - List of SIC and NAICS Codes
Federal MSGP Appendix O - Summary of Reports Permit Submittals
Federal MSGP Appendix P - List of Federal CERCLA Sites
Federal Multi-Sector General Permit (MSGP) - Part 9
Federal Multi-Sector General Permit (MSGP) - Part 8
Federal Multi-Sector General Permit (MSGP) - Parts 1-7
Federal Multi-Sector General Permit (MSGP) Fact Sheet
Federal Multi-Sector General Permit (MSGP)
Federal Register Notice Vol. 80, No. 115
Federal Suggested Format for Submitting a Change Notice of Intent
Federal Guidance Manual for Conditional Exclusion from Storm Water Permitting
Federal Industrial SWPPP Template
Federal Developing Your SWPPP Industrial Guide
Federal Industrial Stormwater Monitoring and Sampling Guide
Federal - Compendium Part 1 - Six Minimum Control Measure Provisions
Federal - Compendium Part 2 - Post-Construction Standards
Federal - Compendium Part 3 - Water Quality-Based Requirements
Federal - Compendium Part 4 - Transportation Stormwater Permit Compendium
Federal - Comprehensive Summary of State Post Construction Stormwater Standards
Federal - MS4 Program Evaluation Guidance
Federal - MS4 Permit Improvement Guide
Federal - MS4 Permits – Compendium of Clear, Specific and Measurable Permitting Examples - Introduction
Federal - Revisions to the Memorandum - Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs)
Federal - TMDLs to Stormwater Permits Handbook - DRAFT
Federal - Guidance for Municipal Stormwater Funding
Federal - IDDE Guidance Manual (CWP)
Federal - EPA - Stormwater Phase II Final Rule - IDDE MCM
Idaho Permit Application Process
The Idaho Department of Environmental Quality (IDEQ) integrates the EPA’s Federal Construction General Permit for all stormwater discharges on project sites that: (1) land disturbing activities equal to, or greater than one (1) acre; and (2) construction activities involving less than one (1) acre and which is part of a common plan of development or sale equal to or greater than one (1) acre.
Coverage under the Federal Construction General Permit (CGP) must be attained for Stormwater Discharge Associated with Construction Activity. This means that the discharge of pollutants in stormwater to waters of the United States (Idaho) from areas where land disturbing activities (e.g., clearing, grading, or excavation) occur, or where construction materials or equipment storage or maintenance (e.g., fill piles, borrow area, concrete truck chute wash down, fueling), or other industrial stormwater directly related to the construction process (e.g., concrete or asphalt batch plants), are located.
Idaho Storm Water Pollution Prevention Plan Requirements
As mandated by the Federal Construction General Permit (CGP) via the state of Idaho and the Idaho Department of Environmental Quality (IDEQ), any owner or operator seeking permit coverage under the Federal CGP must design and implement a Storm Water Pollution Prevention Plan (SWPPP). A complete and compliant Storm Water Pollution Prevention Plan (SWPPP) will include the following criteria:
(1) Stormwater Team: Each owner/operator, or group of owners/operators are mandated to assemble a “stormwater team” which is responsible for developing, maintaining, and modifying the SWPPP. Each member of the “stormwater team” should be identified by name and individual responsibilities which will occur throughout the course of the construction project.
(2) Other Operators: A list of all other operators that will be working on the construction site, even if they did not partake in the creation of the Storm Water Pollution Prevention Plan (SWPPP).
(3) Nature of Construction: the SWPPP must describe the nature of construction activities, including the size of the property, the total acreage expected to be disturbed by construction activities, and the maximum area expected to be disturbed at one time.
*Note: If conducting construction activities in response to an “Emergency-related project,” an owner or operator shall document the cause of the public emergency, information substantiating its occurrence, and the corrective actions taken in response to the emergency.
(4) Sequence of Events/Estimated Project Dates: An outline of the sequence for which construction activity will occur, including start dates and an estimated duration to achieve project completion is required. If plans change due to unforeseen circumstances, modifications to the SWPPP should be documented.
(5) Site Map: a compliant site map will include (a) boundaries of the site and specific locations as to where land disturbing activity will occur; (b) approximate slops before and after grading activities occur; (c) locations where sediment, soil, and other construction materials will be stored; (d) locations of all surface waters that exist within the vicinity of the site; (e) locations of all impervious surfaces that will be created by the completion of the project; (f) locations of construction support activities; (g) the boundary lines of any natural buffer zones within the vicinity of the site; (h)areas of federally listed endangered habitats or species; (i) topography of the site such as existing vegetative covers and stormwater drainage patterns; (j) discharge locations for both stormwater and non-stormwater runoff; and (k) locations of all Best Management Practices (BMPs) or other protective measures.
(6) Construction Site Pollutants: A list of all pollutants that will be produced from construction activities on a site. An inventory documenting the various types of pollutants generated from each individual construction activity within the project site should be kept. Special attention should be placed on any locations within the site that could have the potential for leaks, spills, or any other forms of non-compliance.
(7) Non-Stormwater Discharges: A list identifying all sources of authorized non-stormwater discharges should be made.
(8) Description of Best Management Practices (BMPs): Each stormwater control measure that are or will be installed throughout the duration of the construction project should be listed in detail within the SWPPP.
(9) Waste Management & Stabilization Methods: A description for handling all waste disposal from construction activities and all temporary/or final stabilization practices that will be used to comply with the standards of the Federal Construction General Permit (CGP) is required.
(10) Spill Prevention Methods: All spill prevention methods and procedures for notifying the appropriate authority, emergency response personnel, or regulatory agency must be included.
(11) Maintenance Requirements: Maintenance requirements, inspection schedules, and plans for appropriate corrective actions, if deemed necessary, must be included. Such inspections should be led by the appropriate personnel and documented according to the Federal CGP requirements.
Once all of the aforementioned criteria have been included, the SWPPP can be submitted with the Notice of Intent (NOI) to the Idaho Environmental Protection Agency. All owners and operators are required to keep an up-to-date copy of their Storm Water Pollution Prevention Plan (SWPPP) on site and easily accessible upon reasonable request.
Modifications to the Storm Water Pollution Prevention Plan (SWPPP) should be made to document all alterations, incidences of non-compliance if applicable, and corrective measures used during construction activity. All SWPPP modifications must be made within seven (7) days of the corresponding incidence. All records should specifically track inspection and SWPPP modification dates, as well as the name and contact information of the responsible person.
Idaho Construction Stormwater Inspection Frequency
The Idaho Department of Environmental Quality (IDEQ) integrates the EPA’s Federal Construction General Permit for all stormwater discharges on project sites that: (1) land disturbing activities equal to, or greater than one (1) acre; and (2) construction activities involving less than one (1) acre and which is part of a common plan of development or sale equal to or greater than one (1) acre.
Coverage under the Federal Construction General Permit (CGP) must be attained for Stormwater Discharge Associated with Construction Activity. This means that the discharge of pollutants in stormwater to waters of the United States (Idaho) from areas where land disturbing activities (e.g., clearing, grading, or excavation) occur, or where construction materials or equipment storage or maintenance (e.g., fill piles, borrow area, concrete truck chute wash down, fueling), or other industrial stormwater directly related to the construction process (e.g., concrete or asphalt batch plants), are located.
Idaho Construction Stormwater - Credential Requirements
Prior to the commencement of any land-disturbing construction activities, it is imperative that all necessary personnel understand the requirements of the Federal Construction General Permit (CGP), and the criteria of the Idaho Department of Environmental Quality (IDEQ) for upholding water quality standards and eliminating pollutants connected to stormwater discharges from construction sites.
Although not required to document formal training for subcontractors or other outsourced service providers, the owner of operator of the construction site must ensure that such personnel understand the compliance requirements associated with their job scope.
At a minimum, personnel should be trained to understand (1) the location of all stormwater controls and how to maintain them; (2) the proper procedures to follow with respect to the Federal CGP’s pollution prevention requirements; and (3) when and how to conduct inspections and create post-inspection reports ( only applicable to personnel responsible for conducting the inspections).
Idaho Final Stabilization for Construction Activities
Before a construction project can be deemed complete and the Notice of Termination (NOT) can be submitted for approval, the entire site must meet compliant levels of final stabilization. The Federal CGP requires that all stabilization methods are initiated immediately after land-disturbing activity has temporarily or permanently ceased for any portion of the site.
*Note: Land-disturbing activities have permanently ceased when all clearing and excavation activities located on a portion of the site that will not have permanent structures is complete. Land-disturbing activities have temporarily ceased when clearing, grading, and excavation within any portion of the site that will not have permanent structures has stopped for fourteen (14) or more days, but will resume in the future.
Stabilization activities are required to be implemented as soon as practicable, but no longer than fourteen (14) days after the initiation of stabilization activities. Activities that constitute stabilization initiation include: (1) prepping soil for vegetative and non-vegetative covers; (2) applying mulch or other non-vegetative products to exposed areas of the site; (3) seeding or planting on exposed areas; and (4) the finalization of arrangements to have stabilization complete and in accordance with the requirements of the Federal Construction General Permit (CGP).
Final stabilization requirements vary based on the location and topographical composition of the construction site. For all project sites except those located in arid and semi-arid areas or on agricultural lands, an owner or operator must implement a perennial seed or planted vegetation which provides an established uniform vegetative cover that is seventy percent (70%) or more of the density of the native vegetation or pre-construction vegetative cover. For arid, semi-arid, or drought-stricken project sites, an owner or operator will have achieved final stabilization if the area that has been seeded or planted will provide established vegetation within three (3) years and covers seventy percent (70%) or more of the original pre-construction vegetative cover. The owner or operator also has a responsibility to design and install non-vegetative erosion controls that will provide a protective cover for at least three (3) years without active maintenance.
Idaho Stormwater Permit Termination Process - Notice of Termination (NOT)
Until coverage under the Federal Construction General Permit (CGP) within the State of Idaho is properly terminated, owners or operators are required to comply with all permit conditions. To terminate coverage, a Notice of Termination (NOT) must be submitted to the Environmental Protection Agency (EPA).
The Notice of Termination must require the following information:
(1) NPDES tracking number provided by the Environmental Protection Agency (EPA) when permit coverage was issued.
(2) Owner or operator contact information.
(3) Name of the construction project and an address if available. If an address is not available, a description of the street and local reference points should be included.
(4) The actual Notice of Termination with proper signatures.
Prior to submitting the Notice of Termination (NOT), all land disturbing activities and construction support activities must be complete. Additionally, the following steps are required for authorization to terminate permit coverage: (1) All vegetative and non-vegetative methods of stabilization must be achieved; (2) All materials, waste, and waste handling devices must be removed from the site and properly disposed of; (3) All stormwater control measures that are not intended for long-term use have been removed; and (4) Proper removal of all potential pollutants and pollutants generated from construction activities has occurred.
Once all the necessary requirements of the Notice of Termination have been fulfilled, the NOT can be submitted to the EPA via their electronic NOI system (“eNOI”). Approval must be granted to individuals needing to submit a paper format of the Notice of Termination (NOT). Onwers and operators have thirty (30) days after the initiation of final stabilization to complete and submit the NOT. If accepted, permit coverage will terminate at midnight on the day the NOI is processed.
Pacific Northwest
Margaret McCauley
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(206) 553-1772
US EPA, Region 10 / Industrial & Construction
1200 6th Ave, Suite 900
Seattle, WA, 98101-1128
AJ Maupin
Idaho Department of Environmental Quality
(208) 373-0167
Email AJ »
Agency Website »
1410 N. Hilton
Boise, ID, 83706
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