Environmental_Document.pdf

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Franklin Road – Black Cat to McDermott, NWW-2026-00143 1

Idaho Department of Environmental Quality Final Section 401 Water Quality Certification

July 17, 2026

Project Name: Franklin Road – Black Cat to McDermott, NWW-2026-00143

Permit Name and Number: Nationwide Permit 14, Linear Transportation

Applicant/Authorized Agent: Logan Hansen, Ada County Highway District

Project Location: The project is located on Franklin Road, between the crossroads: Black Cat Rd and McDermott, Merdian, Ada County, Idaho; 43.0604840° and -116.464959°

Receiving Water Body: Perkins Drain and Rosenlof Drain – Lower Boise River Subbasin

Pursuant to Section 401(a)(1) of the Federal Water Pollution Control Act (Clean Water Act), as amended; 33 U.S.C. Section 1341(a)(1); 40 CFR § 121; and Idaho Code §§ 39-101 et seq. and 39- 3601 et seq., the Idaho Department of Environmental Quality (DEQ) has authority to review and certify that any discharge of dredged or fill material into waters of the United States will comply with water quality requirements under state law and the Clean Water Act. Consistent with DEQ’s May 6, 2024, Scope Directive for 2023 Clean Water Act § 401 Water Quality Certifications for § 404 Permits (Scope Directive), this review is limited to the water quality-related impacts from the activity subject to the US Army Corps of Engineers (USACE) § 404 permit, including the activity’s construction and any integral operational elements directly tied to that activity. DEQ’s review does not extend to general project operations or ancillary upland activities that are subject to other federal, state, or local regulatory authorities. Moreover, the US Environmental Protection Agency’s (EPA) May 21, 2025, clarification memorandum reiterates that CWA § 401 is limited to considering adverse impacts to water quality, and only insofar as they may prevent compliance with applicable water quality requirements. Conditions or denials may not be based on impacts unrelated to water quality or not within the scope of the federal permit.

In accordance with federal regulations at 40 CFR § 121.4, all project proponents must submit a request for a prefiling meeting at least thirty days in advance of submitting a certification request. A prefiling meeting request was received by DEQ on 4/16/2026. DEQ reviewed the prefiling meeting request and determined that necessary project information submitted with advance notice was sufficient to evaluate potential water quality impacts to act on the certification request within a reasonable period of time.

Based upon review of the federal permit application, readily available water quality related materials, and certification request in accordance with 40 CFR §§ 121.5 (b) and (c) and 121.7 mailto:accessibility@deq.idaho.gov https://www.deq.idaho.gov/about-us/accessibility/

Idaho Department of Environmental Quality § 401 Water Quality Certification

Franklin Road – Black Cat to McDermott, NWW-2026-00143 2

(c), received on, 5/18/2026, DEQ, certifies that if the permittee complies with the terms and conditions imposed by the federal permit and the conditions set forth in this water quality certification, then it is reasonable for DEQ to conclude that the activity will comply with water quality requirements, including applicable requirements of the Clean Water Act §§ 301, 302, 303, 306, and 307, Idaho’s “Water Quality Standards” (IDAPA 58.01.02), and other appropriate water quality requirements of state law. This finding is based on DEQ’s evaluation of the water quality-related impacts from the activity subject to the § 404 permit, consistent with DEQ’s May 6, 2024, Scope Directive and EPA’s May 21, 2025, clarification. Potential impacts unrelated to the permitted activity, or regulated under other authorities, were not evaluated or conditioned under this certification.

Pursuant to Clean Water Act § 401 (a)(1) and 40 CFR § 121.7 (d); and IDAPA 58.01.02.052.08, DEQ issued a 21-day public notice to solicit comments on the draft certification on 6/12/2026 through 7/3/2026. Any public comments received during the 21-day comment period were considered by DEQ to inform the certification decision and conditions.

This certification does not authorize activities by any other state or federal agency or any private individual or entity and does not relieve the permittee of the responsibility to obtain all other required approvals, authorizations, or permits that may be necessary for the project.

1 Project Description The Franklin Road – Black Cat to McDermott project proposes to expand Franklin Road from two lanes to five, install pedestrian and bikes lanes via a 10-foot detached sidewalk, curb and gutter stormwater infrastructure, roadside lighting, and a roundabout at the McDermott Road intersection.

To accommodate the new infrastructure, the project will fill approximately 500 linear feet of the Rosenlof Drain and 250 linear feet of the Perkins Drain. Both drains will be excavated, piped with 24-inch and 30-inch Class III reinforced concrete pipe (RCP), place structural fill six to eight feet beyond the footprint of the headwalls and compact with a mechanized plate compactor, install cast-in-place concrete headwalls at the inlet of the RCP to reshape the drain bottoms, place riprap at the headwalls to prevent scour, and revegetate disturbed areas impacted by construction by reseeding.

Best Management Practices (BMPs), as identified in a site-specific Storm Water Pollution Prevention Plan (SWPPP), will be implemented to prevent sediment and other pollutants from entering the waterway. BMPs include installation of fiber wattles and silt fencing, reseeding disturbed areas, and other measures to contain and filter stormwater runoff.

The project will permanently impact approximately 650 square feet of palustrine emergent (PEM) wetlands and 1,105 square feet of waters below the ordinary high-water mark (OHWM) in Perkins Drain. In Rosenlof Drain, the project will permanently impact approximately 848 square feet of PEM wetlands and 1,632 square feet of waters below the OHWM. In total, the project will result in approximately 1,498 square feet of permanent impacts to PEM wetlands and 2,737 square feet of permanent impacts below the OHWM.

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2 Antidegradation Review Idaho’s antidegradation policy only applies to waters subject to the jurisdiction of the Clean Water Act and establishes three tiers of water quality protection (IDAPA 58.01.02.051, 58.01.02.052).

Tier I Protection. The first level of protection applies to all water bodies subject to Clean Water Act jurisdiction and ensures that existing uses of a water body and the level of water quality necessary to protect those existing uses will be maintained and protected (IDAPA 58.01.02.051.01; 58.01.02.052.01). Additionally, a Tier I review is performed for all new or reissued permits or licenses (IDAPA 58.01.02.052.07).

Tier II Protection. The second level of protection applies to those water bodies considered high quality and ensures that no lowering of water quality will be allowed unless necessary to accommodate important economic or social development (IDAPA 58.01.02.051.02;

58.01.02.052.08).

Tier III Protection. The third level of protection applies to water bodies that have been designated outstanding resource waters and requires that activities do not lower water quality

(IDAPA 58.01.02.051.03; 58.01.02.052.09).

DEQ employs a water-body-by-water-body approach to implementing Idaho’s antidegradation policy. This approach means that any water body fully supporting its beneficial uses will be considered high quality (IDAPA 58.01.02.052.05.a). Any water body not fully supporting its beneficial uses will be provided Tier I protection for that use, unless specific circumstances warranting Tier II protection are met (IDAPA 58.01.02.052.05.c). The most recent federally approved DEQ Integrated Report and supporting data are used to determine support status and the tier of protection (IDAPA 58.01.02.052.05).

2.1 Pollutants of Concern

The pollutant of concern for this project is sediment. As part of the § 401 water quality certification, DEQ requires the applicant to comply with various conditions to protect water quality and ensure compliance with Idaho’s water quality standards, including applicable water quality criteria for the identified pollutant.

The project may result in short-term increases in suspended sediment during construction activities. These effects are evaluated in the context of the § 404 activity footprint and immediate downstream waters.

2.2 Receiving Water Body Level of Protection

This project is located on the Perkins Drain and the Rosenlof Drain within the Lower Boise River subbasin. None of the impacted waterbodies have been assigned an assessment unit (AU), but they may share hydrologic connectivity with the Lower Boise River through Tenmile Creek – 3rd order below Blacks Creek Reservoir (assessment unit (AU) ID17050114SW008_03). According to the most recent federally approved DEQ Integrated Report, this AU has the following https://www.deq.idaho.gov/water-quality/surface-water/monitoring-and-assessment/ https://mapcase.deq.idaho.gov/wq2024/

Franklin Road – Black Cat to McDermott, NWW-2026-00143 4 designated beneficial uses: cold water aquatic life and secondary contact recreation. Because both the Perkins Drain and the Rosenlof Drain are not included in the AU database maintained by DEQ, or the National Hydrography Dataset, they are not designated in Idaho’s water quality standards and are considered man-made waterways (IDAPA 58.01.02.010.58). DEQ protects such waterways for the use for which they were developed, namely agricultural water supply (IDAPA 58.01.02.101.02). Accordingly, DEQ will provide Tier I protection for this water body. In addition to these uses, all waters within the state are protected for agricultural and industrial water supply, wildlife habitat, and aesthetics (IDAPA 58.01.02.100).

2.3 Protection and Maintenance of Existing Uses (Tier I Protection) A Tier I review is performed for all new or reissued permits or licenses, applies to all waters subject to the jurisdiction of the Clean Water Act, and requires demonstration that existing uses and the level of water quality necessary to protect existing uses must be maintained and protected. The numeric and narrative (non-numeric) criteria in the water quality standards are set at levels that ensure protection of existing and designated beneficial uses.

Water bodies not supporting existing or designated beneficial uses must be identified as water quality limited, and a total maximum daily load (TMDL) must be prepared for those pollutants causing impairment. Once a TMDL is developed, discharges of causative pollutants must be consistent with the allocations in the TMDL (IDAPA 58.01.02.055.05). Before developing the TMDL, the water quality standards require applying the antidegradation policy and implementation provisions to maintain and protect uses (IDAPA 58.01.02.055.04).

Throughout the life of the project, the applicant will implement, install, maintain, monitor, and adaptively manage BMPs to reduce erosion and minimize turbidity levels in receiving water bodies downstream of the project. In addition, permanent erosion and sediment controls will be implemented that will minimize or prevent future sediment contributions from the project area.

If the project is conducted according to the provisions of the project plans, federal permit and conditions of this certification, then it is reasonable for DEQ to conclude that the project will comply with the state’s numeric and narrative water quality criteria. These criteria are set at levels that protect and maintain existing and designated beneficial uses.

There is no available information indicating the presence of any existing beneficial uses aside from those that are already designated and discussed above. The conditions in this certification ensure that the level of water quality necessary to protect both existing and designated uses is maintained and protected in compliance with the Tier I provisions of IDAPA 58.01.02.051.01 and 58.01.02.052.07.

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3 Conditions Necessary to Ensure Compliance with Water Quality Standards or Other Appropriate Water Quality Requirements of State Law

The following conditions ensure the Franklin Road – Black Cat to McDermott project complies with Idaho’s water quality standards and other appropriate water quality requirements of state law applicable to the Perkins Drain and the Rosenlof Drain.

3.1 General Conditions

This certification is based on review of the federal permit application, readily available water quality related materials, and certification request submitted by Ada County Highway District on 5/18/2026, and is conditioned upon the requirement that any modification (e.g., change in work windows, etc.) of the permitted activity must first be provided to DEQ for review to determine compliance with Idaho’s water quality standards.

The following conditions apply solely to the activity subject to the § 404 permit. They are necessary to assure compliance with applicable water quality requirements as required by 40 CFR 121.3. Conditions do not extend to aspects of general project operation or unrelated upland activities regulated under other programs. Because DEQ is certifying only the activity described in the certification request, this condition ensures that discharges under circumstances that differ from those described in the certification request will comply with 33 U.S.C. § 1341, 40 CFR § 121, and other applicable water quality requirements, including without limitation 33 U.S.C. § 1311(a), Idaho Code § 39-108, IDAPA 58.01.02.051, IDAPA 58.01.02.052, IDAPA 58.01.02.080, IDAPA 58.01.02.200, IDAPA 58.01.02.210, IDAPA 58.01.02.250, IDAPA 58.01.02.251, IDAPA 58.01.02.252, IDAPA 58.01.02.253, and IDAPA 58.01.02.400.

1. DEQ reserves the right to modify this certification in accordance with 40 CFR § 121.10 if DEQ determines that, due to changes in relevant circumstances—including without limitation, changes in project activities, the characteristics of the receiving water bodies, or state water quality standards—there is no longer reasonable assurance of compliance with the water quality standards or other appropriate requirements of state law.

2. If ownership of the project changes, the certification holder must notify DEQ, in writing, upon transferring this ownership or responsibility for compliance with these conditions to another person or party. The new owner/operator must request, in writing, the transfer of this water quality certification to the new name.

3. A copy of this certification must be kept on the job site and readily available for review by any contractor working on the project and any federal, state, or local government personnel.

4. The applicant is responsible for all work done by contractors and must ensure the contractors are informed of and follow all the conditions described in this certification and the federal permit.

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5. The applicant must provide access to the project site upon request by DEQ personnel for site inspections, monitoring, and/or to ensure that conditions of this certification are being met.

6. Projects must be conducted in a manner that complies with numeric and narrative criteria in Idaho’s water quality standards, including criteria for sediment, turbidity, temperature, and dissolved oxygen.

3.2 Design, Implementation, and Maintenance of Best Management Practices (BMPs)

The following condition is necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation, IDAPA 58.01.02.200, IDAPA 58.01.02.250, IDAPA 58.01.02.251, IDAPA 58.01.02.252, IDAPA 58.01.02.350, and IDAPA 58.01.02.401.

1. BMPs must be properly designed, implemented, and maintained to protect beneficial uses and minimize pollutant loading to surface waters. Proper installation and operation of BMPs are required to ensure the provisions of IDAPA 58.01.02.052 are met. To ensure that BMPs are operating properly and to demonstrate that degradation has not occurred, the permittee must monitor and evaluate BMP effectiveness daily during project activities to ensure that water quality standards are met. BMP inspection logs and documentation of corrective measures (if necessary) must be maintained on site, along with a copy of this certification and provided to DEQ upon request.

DEQ publishes the Idaho Catalog of Storm Water Best Management Practices (DEQ 2020), which identifies approved practices for controlling erosion and sediment during and following construction. Alternative sources of BMPs may be used only where consistent with state water quality standards and the conditions of this certification.

3.3 Fill Material

The following conditions are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.051, IDAPA 58.01.02.200, IDAPA 58.01.02.210, IDAPA 58.01.02.250, IDAPA 58.01.02.251, IDAPA 58.01.02.252, IDAPA 58.01.02.253, and IDAPA 58.01.02.400.

1. Fill material subject to suspension will be free of easily suspended fine material. Only clean materials may be placed as fill.

2. If dredged material is proposed for use as fill material and there is a possibility the material may be contaminated, then the permittee must assess and characterize sediment to determine the suitability of dredge material for unconfined-aquatic placement; determine the suitability of post-dredge surfaces; and predict the effect on water quality during dredging. Sediment assessment and characterization following the procedures in the Sediment Evaluation Framework for the Pacific Northwest (RSET 2018) satisfies this requirement. A different assessment and characterization methodology may be used if DEQ approves the methodology in writing.

https://www2.deq.idaho.gov/admin/LEIA/api/document/download/14968 https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll11/id/2548

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3. When sand is utilized as fill material, appropriate BMPs must be implemented to ensure sand will not be easily dispersed (e.g., filter fabric anchored over the sand or other confinement).

4. Temporary fills must be removed in their entirety on or before construction completion.

3.4 Erosion and Sediment Control

The following conditions are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.051, IDAPA 58.01.02.200, IDAPA 58.01.02.250, IDAPA 58.01.02.253, and IDAPA 58.01.02.400.

1. BMPs for sediment and erosion control suitable to prevent exceedances of Idaho’s water quality standards and consistency with TMDLs must be selected and installed before starting construction at the site.

2. Temporary and permanent erosion and sediment control measures must be installed around the perimeter of the project or initial work areas to control and prevent excess sediment from entering waters of the United States.

3. Temporary and permanent erosion and sediment control measures must be installed at the earliest practicable time consistent with good construction practices and must be maintained as necessary throughout the project.

4. Structural fill or bank protection must consist of materials that are placed and maintained to withstand predictable high flows in the waters of the United States.

5. A BMP inspection and maintenance plan must be developed and implemented. At a minimum, BMPs must be inspected and maintained daily during project implementation and replaced or augmented if they are not effective. BMP inspection logs and documentation of corrective measures (if necessary) must be maintained on site, along with a copy of this certification and provided to DEQ upon request.

6. All excess dredged or fill material generated by the authorized activity must be contained and properly disposed of so it does not enter waters of the United States or cause water quality degradation.

7. Disturbed areas suitable for vegetation must be seeded or revegetated to stabilize soils and prevent erosion to the maximum extent practicable (EPA 2000).

8. Maximum fill slopes must be material that is structurally stable once placed and does not slough into the stream channel during construction, during periods before revegetation, or after vegetation is established.

9. Sediment from disturbed areas or sediment that can be tracked by vehicles onto pavement must not leave the site in amounts reasonably expected to enter waters of the United States. Placement of clean aggregate at all construction entrances or exits and other BMPs such as truck or wheel washes, if needed, must be used when earth-moving equipment will be leaving the site and traveling on paved surfaces to prevent track-out.

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3.5 Turbidity

The following conditions are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.051, IDAPA 58.01.02.200.08, IDAPA 58.01.02.250.02.e, IDAPA 58.01.02.253, and IDAPA 58.01.02.400.

1. Sediment resulting from activities—including BMP failures, construction mishaps, spills, or any unplanned event—must be mitigated to prevent violations of Idaho’s water quality standards. Any violation of this standard must be reported to the DEQ regional office immediately.

2. Throughout the life of the project, the applicant must implement, maintain, monitor, and adaptively manage BMPs—such as silt curtains, geotextile fabrics, and silt fences— to minimize instream sediment suspension, turbidity, and the potential for spills or mishaps to affect surface waters.

3. Visual observation is acceptable to determine whether project activities, BMPs, or unanticipated events (e.g., construction mishaps or spills) are contributing to increased turbidity. If a sediment plume is observed, the project may be causing an exceedance of water quality standards, and the permittee must inspect BMPs and the project activity area to identify the cause. If the BMPs, site conditions, or any incident are contributing to turbidity, the permittee must take corrective measures and modify the activity, address the incident, and implement additional or revised BMPs.

4. If a visible sediment plume persists after corrective measures have been implemented, turbidity monitoring consistent with Table 1 and Appendix A is required.

a. A properly and regularly calibrated turbidimeter is required for field measurements. The turbidimeter should be calibrated before each use or in accordance with the manufacturer’s recommendations. Calibration logs must be maintained and made available to DEQ upon request. Instantaneous grab samples must be collected upstream of the disturbance to determine background turbidity and downstream within the visible plume to evaluate project impacts. Location, date, time, and turbidity values must be recorded for each sample.

b. Results from the downstream sampling location must be compared to the upstream sample location or background turbidity to determine whether project activities are causing an exceedance of Idaho’s water quality standards. If the downstream turbidity is 50 nephelometric turbidity units (NTUs) or greater than the upstream turbidity, then the project is causing an exceedance of the water quality standards. Any exceedance of the turbidity standard must be reported to the DEQ regional office within 24 hours of the sample event.

c. Work (or earth-disturbing activities) may resume when turbidity readings return to within 50 NTU above background, or if turbidity has exceeded 25 NTU above background for more than 10 consecutive days, once readings have remained below 25 NTU above background for at least 24 consecutive hours.

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d. Daily turbidity monitoring logs must be available to DEQ upon request. Logs must describe all exceedances, the causes (including spills or incidents, if applicable), corrective measures taken, and the effectiveness of those measures.

Table 1. Turbidimeter monitoring and sampling when a plume is observed.

Turbidity Above

Backgrounda Monitoring/Sampling Frequencya Additional Actions Required

0 to 24 NTU Visual monitoring every 2 hours. No sampling required.

None

25 to 49 NTU Collect samples every 2 hours. Continue work for up to 8 hours within any 24-hour period, then STOP work until turbidity returns to acceptable levels.

25 NTU for 10 or more consecutive days

Sample before and after implementing corrective actions, following instructionsb

STOP work, implement corrective actions, and follow instructionsb; notify DEQ regional office

50 NTU or more Sample before and after implementing corrective actions, following instructionsc

STOP work, implement corrective actions, and follow instructionsc; notify DEQ regional office

a. For any required turbidity sampling, collect and report three measurements at each monitoring location. Use the maximum value of three measurements to determine compliance following Table 1 directions.

b. Instructions: If BMPs appear to be functioning properly, the permittee must modify the activity or implement corrective actions, such as installing additional or modifying existing BMPs, until turbidity measurements indicate turbidity standards are met. Sampling may cease once a sediment plume is no longer observed. Work may resume when the sediment plume is no longer visible and turbidity measurements remain consecutively below

25 NTU.

c. Instructions: If BMPs appear to be functioning properly, the permittee must modify the activity or implement corrective action, such as installing additional or modifying existing BMPs, until turbidity measurements indicate turbidity standards are met. Sampling may cease when the sediment plume is no longer visible. Work may resume when the sediment plume is no longer visible and turbidity measurements remain below 50 NTU.

3.6 In-Water Work

The following conditions are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.051, IDAPA 58.01.02.200, IDAPA 58.01.02.250, IDAPA 58.01.02.253, and IDAPA 58.01.02.400.

1. When practicable, equipment must work from an upland site to minimize disturbance of waters of the United States.

2. Construction affecting the streambed or streambanks must generally occur during low-flow periods, and where practicable, coincide with suitable in-water work periods for aquatic life.

3. To the maximum extent practicable, where fill is needed, temporary crossings must be installed perpendicular to the channel and located in areas that will result in the least environmental impact. Temporary crossings must be stabilized with clean gravel or treated with other measures that are equally effective in reducing impacts. All temporary crossings must be removed as soon as possible after project completion or when they are no longer needed.

4. To the maximum extent practicable, heavy equipment operating in wetlands must be placed on mats or suitably designed pads to prevent damage to wetland soil and vegetation. However, during winter conditions, mats or pads may not be required if the

Franklin Road – Black Cat to McDermott, NWW-2026-00143 10 ground is adequately frozen and construction activities are expected to result in minimal impacts.

5. Wastewater from concrete washout and equipment cleaning must be managed to prevent discharge to waters of the United States. Control measures must be maintained to prevent or minimize the potential for wet concrete, slurry, or wash water from entering waters of the United States.

6. To the maximum extent practicable, equipment operating over water or directly adjacent to the channel must utilize environmentally acceptable lubricants or hydraulic fluids that are less toxic to fish and other aquatic organisms.

3.7 Vegetation Protection and Restoration

The following conditions are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.051, IDAPA 58.01.02.200, IDAPA 58.01.02.250, IDAPA 58.01.02.253, and IDAPA 58.01.02.400.

1. To the maximum extent practicable, locate staging areas and access points in open, upland areas.

a. Fencing and other protective barriers should be used to mark the construction areas.

b. To the maximum extent practicable, minimize disturbance of native vegetation to reduce soil erosion, sediment delivery of sediment to waterways, and impacts to aquatic biota.

2. Existing riparian vegetation within the project area must remain undisturbed to the maximum extent practicable. Where disturbance is unavoidable, implement BMPs to minimize impacts and replant disturbed areas with native riparian species that provide equivalent or improved shading, bank stability, and habitat functions within the current or next appropriate planting season.

3. Where project activities unavoidably remove native riparian or wetland vegetation, successfully reestablish native species within the current or next appropriate planting season to the maximum extent practicable. Restoration must achieve, at minimum, preproject levels of water quality benefit or result in an overall ecosystem improvement.

3.8 Management of Hazardous or Deleterious Materials

The following conditions are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.051, IDAPA 58.01.02.080, IDAPA 58.01.02.200, IDAPA 58.01.02.400, IDAPA 58.01.02.800, and IDAPA 58.01.02.850.

1. Petroleum products and hazardous, toxic, and/or deleterious materials must not be stored, disposed of, or accumulated adjacent to or in the immediate vicinity of waters of the United States. Adequate measures and controls must ensure that those materials

Franklin Road – Black Cat to McDermott, NWW-2026-00143 11 will not enter waters of the United States because of high water, precipitation runoff, wind, storage facility failure, accidents, or unauthorized third-party activities.

2. Secondary containment must be provided for all chemical materials stored or used on-site to prevent spills, leaks, or releases to soil or waters of the United States.

Containment systems must be designed and maintained in accordance with applicable industry standards and manufacturer recommendations.

3. Daily inspections of all fluid systems on equipment to be used in or near waters of the United States must ensure no leaks or potential leaks exist before equipment use. A logbook of daily equipment inspections must be kept on site and provided to DEQ upon request.

4. Equipment and machinery must not be refueled, repaired, or serviced within waters of the United States.

5. Equipment and machinery must be steam cleaned of oils and grease in an upland location or staging area with appropriate wastewater controls and treatment capability before entering waters of the United States. Any wastewater or wash water must not enter waters of the United States.

6. Emergency spill response procedures must be in place and include a spill response kit (e.g., oil absorbent booms or other equipment).

7. If an unauthorized release of hazardous material to waters of the United States or to land occurs and there is a likelihood it will enter waters of the United States, the responsible persons in charge must:

a. Make every reasonable effort to abate and stop a continuing spill.

b. Make every reasonable effort to contain spilled material so it will not reach waters of the United States.

c. Call 911 if immediate assistance is required to control, contain, or clean up the spill. If no assistance is needed in cleaning up the spill, contact the appropriate DEQ regional office during normal working hours or Idaho State Communications Center after normal working hours (1-800-632-8000). If the spilled volume is above federal reportable quantities, contact the National Response Center (1- 800-424-8802).

d. Contact Boise Regional Office: (208) 373-0550.

8. Collect, remove, and properly dispose of spill and cleanup materials in accordance with all federal, state, and local regulations.

3.9 Culverts

The following conditions to control erosion, sediment, and turbidity are necessary for the protection of beneficial uses according to Idaho’s water quality standards, including without limitation IDAPA 58.01.02.200 and IDAPA 58.01.02.250.

1. To prevent road surface and culvert bedding material from entering a stream, culvert crossings must include BMPs to retain road base and culvert bedding material. For

Franklin Road – Black Cat to McDermott, NWW-2026-00143 12 perennial waters, the permittee should consider Idaho’s “Stream Channel Alterations Rules” (IDAPA 37.03.07). Another source of BMPs for culvert installation are found in the “Rules Pertaining to the Idaho Forest Practices Act” (IDAPA 20.02.01). Examples of BMPs include, but are not limited to: parapets, wing walls, inlet and outlet rock armoring, compaction, suitable bedding material, antiseep barriers such as bentonite clay, or other acceptable roadway retention systems.

2. Culverts must be sized appropriately to maintain the natural drainage patterns.

3. Culverts must not constrict the stream channel or direct flow toward the streambank.

Adequate grade control must be installed to prevent channel erosion or sediment buildup.

4. Culverts for fish-bearing waterways must be installed so they do not impede fish passage.

5. The culvert outflow must be armored with riprap to provide erosion control. This riprap will be clean, angular, dense rock that is free of fines and resistant to aquatic decomposition.

3.10 Dredge Material Management

This condition ensures that there is no unauthorized discharge from upland disposal sites according to 33 U.S.C. § 1311(a) and Idaho’s water quality requirements, including without limitation Idaho Code § 39-108, IDAPA 58.01.02.080, and IDAPA 58.01.02.400.

1. Upland disposal of dredged material must prevent the material from reentering waters of the United States.

3.11 Pollutants/Toxins

In conformance with IDAPA 58.01.02.200, the use of chemicals such as sterilants, growth inhibitors, fertilizers, and deicing salts during construction should be limited to the best estimate of optimum application rates. All reasonable measures must be taken to avoid excess application and introduction of chemicals into waters of the United States.

4 Required Notification The permittee must notify the Boise Regional Office when authorized work begins and if the applicant or organization is transferred or changes.

5 Right to Appeal Final Certification The final § 401 Water Quality Certification may be appealed by submitting a petition to initiate a contested case, pursuant to Idaho Code § 39-107(5) and the “Rules of Administrative Procedure before the Board of Environmental Quality” (IDAPA 58.01.23), within 35-days of the date of the final certification.

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Questions or comments regarding the actions taken in this certification should be directed to Meghan Cline in the Boise Regional Office at Meghan.Cline@deq.idaho.gov or (208) 373-0514.

Troy Smith Regional Administrator Boise Regional Office mailto:Meghan.Cline@deq.idaho.gov https://secure.na3.documents.adobe.com/verifier?tx=CBJCHBCAABAAExLvMRokzlsvHpIKQAlpUCkJ-E3U6CmX

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References DEQ (Idaho Department of Environmental Quality). 2020. Idaho Catalog of Storm Water Best

Management Practices. Boise, ID. https://www.deq.idaho.gov/water-quality/wastewater/storm-water/

DEQ (Idaho Department of Environmental Quality). 2024. Idaho Department of Environmental Quality 2024 Integrated Report. Boise, ID.

https://www2.deq.idaho.gov/admin/LEIA/api/document/download/23740

EPA (US Environmental Protection Agency). 2000. National Menu of Best Management Practices (BMPs) for Stormwater. https://www.epa.gov/npdes/national-menu-best-management-practices-bmps-stormwater

RSET (Northwest Regional Sediment Evaluation Team). 2018. Sediment Evaluation Framework for the Pacific Northwest. Prepared by the RSET Agencies.

https://www.deq.idaho.gov/water-quality/wastewater/storm-water/ https://www.deq.idaho.gov/water-quality/wastewater/storm-water/ https://www2.deq.idaho.gov/admin/LEIA/api/document/download/23740 https://www.epa.gov/npdes/national-menu-best-management-practices-bmps-stormwater https://www.epa.gov/npdes/national-menu-best-management-practices-bmps-stormwater

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Appendix A. Turbidity Monitoring Overview