ak-a2020161_SWPPP.pdf

Stormwater Pollution Prevention Plan (SWPPP)

For Construction Activities at:

Project Name: Connecting Anchorage Trail Improvements, AK

ANCHORAGE T 2016(1),

Project Site Location: Far North Bicentennial Park

City, County, State, Zip Code: Anchorage, Municipality of Anchorage, AK, 99507

SWPPP Prepared for:

Organization Name: FHWA, Western Federal Lands Highway Division

Address: 610 East Fifth Street

Vancouver, WA 98661-3801

Telephone Number: 360-619-7700

SWPPP Prepared by:

Name, Title: Alexandra Jefferies, P.E., Senior Engineer

Company/Organization: PND Engineers, Inc.

Address: 1506 W. 36th Ave.

Anchorage, AK 99503

Telephone Number: 907-561-1011

SWPPP Preparation Date: October 16, 2020

Estimated Construction Start Date for Tour of Anchorage Trail: July 19th, 2022 Estimated Construction Completion Date for Tour of Anchorage Trail: October 8th, 2022

Estimated Construction Start Date for North Gasline Bridge Trail: August 23rd, 2022 Estimated Construction Completion Date for North Gasline Trail: November 2nd, 2022

Estimated Revegetation Start Date for Tour of Anchorage Trail and North Gasline Trail: May 23rd, 2023 Estimated Revegetation Completion Date for Tour of Anchorage Trail and North Gasline Trail: May 27th, 2023

SWPPP TABs (SWPPP Inclusions)

TAB 1: SWPPP Narrative

TAB 2: NPDES Permit (Construction General Permit or Corresponding State Permit)

TAB 3: NOI, EPA/State Acknowledgement, Other Applicable EPA/State Correspondence

TAB 4: Delegation of Authority

TAB 5: Vicinity Maps

TAB 6: Erosion/Sediment Control Plan Sheets (plan set and BMP typical details)

TAB 7: Revegetation Plan (if applicable)

TAB 8: SWPPP Amendment Log

TAB 9: Inspection Reports

TAB 10: Corrective Action Log

TAB 11: Water Quality Monitoring, Reporting Requirements, and Reports (if applicable)

TAB 12: Training/Certification Log

TAB 13: Government-Selected Waste, Borrow, Staging Sites

TAB 14: Grading and Stabilization Log

TAB 15: Hazardous Spill Plan or SPCC

TAB 16: Threatened and Endangered Species (Section 7) and Historic Preservation (Section 106) Documentation

TAB 17: NPDES Quality Assurance Checklist

TAB 18: NPDES Notice of Termination (NOT)

TAB 1:

SWPPP NARRATIVE

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Table of Contents

SECTION 1: RESPONSIBLE PARTIES/CONTACT INFORMATION

1.1 Operator(s):

1.2 Construction Site SWPPP Contact(s):

1.3 SWPPP Prepared by:

1.4 NPDES Stormwater Permit

1.5 SWPPP Administrator

1.6 Permitting Authority for FHWA/WFLHD Projects

SECTION 2: PROJECT INFORMATION

2.1 Project Name and Location

2.2 Project Site Characteristics

SECTION 3: NATURE OF CONSTRUCTION ACTIVITY

3.1 General Description of Project and Scope of Work:

3.2 Sequence and Estimated Dates of Construction Activities

3.3 Potential Sources of Pollutants

SECTION 4: SITE MAPS

SECTION 5: DISCHARGES

5.1 Allowable Non-Stormwater Discharges

5.2 Receiving Waters:

5.3 Water Quality Monitoring Requirements

SECTION 6: COMPLIANCE WITH OTHER APPLICABLE REQUIREMENTS

6.1 Endangered Species Protection

6.2 Historic Preservation

6.3 Safe Drinking Water Act Underground Injection Control Requirements

SECTION 7: EROSION AND SEDIMENT CONTROLS

7.1 Natural Buffers or Equivalent Sediment Controls (Required for EPA CGP states only – ID, WA) 20

7.2 Perimeter Controls

7.3 Sediment Track-Out

7.4 Stockpiled Soil or Other Erodible Materials

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7.5 Minimize Dust

7.6 Minimize Disturbance of Steep Slopes

7.7 Topsoil Conservation

7.8 Minimize Soil Compaction

7.9 Storm Drain Inlets and Culvert Inlets

7.10 Constructed Stormwater Conveyance Channels and Culvert Outlets

7.11 Sediment Basins

7.12 Chemical Treatment

7.13 Dewatering Practices

7.14 Erosion Control and Stabilization

7.15 Removal of BMPs

7.16 Post Construction Measures

SECTION 8: OPERATIONAL CONTROLS/GOOD HOUSEKEEPING MEASURES

8.1 Hazardous Spill Plan

8.2 Spills/Releases in Excess of Reportable Quantities

8.3 Equipment/Vehicle Fueling and Maintenance Practices

8.4 Equipment/Vehicle Washing

8.5 Material Handling and Waste Management

8.6 Designate Concrete Washout Areas

SECTION 9: INSPECTIONS

9.1 Inspection Frequency

9.2 Corrective Actions

SECTION 10: DELEGATIONS OF AUTHORITY

SECTION 11: STAFF TRAINING

SECTION 12: CERTIFICATION AND NOTIFICATION

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Section 1: Responsible Parties/Contact Information

1.1 Operator(s):

Organization Name: FHWA, Western Federal Lands Highway Division (WFLHD) Address: 610 East Fifth Street

Vancouver, WA 98661-3801 Telephone Number: 360-619-7700

General Contractor Name:

TBD

Address:

Telephone Number:

Contractor and PE Note: Fill in all incomplete information following contract award date and prior to start of construction

1.2 Construction Site SWPPP Contact(s):

FHWA Contact Name:

Title:

Brandon Stokes Project Manager

Address: 610 East Fifth Street, Vancouver WA 98661 Telephone Number: 306.210.3636

General Contractor Company:

TBD

Erosion Control Supervisor Name:

Address:

Telephone Number:

1.3 SWPPP Prepared by:

Organization/Company: PND Engineers, Inc.

Name, Position: Alexandra Jefferies, PE, Senior Engineer Role/Responsibility SWPPP Preparer Telephone Number: 907-561-1011 Email: ajefferies@pndengineers.com

1.4 NPDES Stormwater Permit

The Applicable EPA/State NPDES Stormwater Permit is located in TAB 2. The Project NOI and EPA/State Acknowledgement with NPDES Tracking Number is located in TAB 3.

1.5 SWPPP Administrator

The General Contractor (section 1.2) is responsible for maintaining the project SWPPP of Record. The General Contractor will provide a qualified Erosion Control Supervisor, who is

[2] responsible for managing the installation, maintenance, inspection, and reporting for erosion and sediment control measures, shall maintain and update the project SWPPP of Record and prepare all documentation required by the project NPDES stormwater permit and SWPPP.

The Erosion Control Supervisor (ECS) is identified in section 1.2 and his/her qualifications are documented in TAB 12.

The FHWA/WFLHD Project Engineer (PE) is the duly authorized representative of the FHWA for the purpose of overseeing compliance with the NPDES stormwater permit and SWPPP at the construction site. See Delegation of Authority TAB 4.

All SWPPP documentation, revisions/updates, and reports will be approved/signed by both the General Contractor’s ECS and the FHWA PE.

1.6 Permitting Authority for FHWA/WFLHD Projects

Delivery Confirmation documentation of the NOI is located in TAB 3.

The applicable EPA/State NPDES permit is located in TAB 2 Alaska Department of Environmental Conservation (ADEC)

State Permitting Authority Alaska ADEC is permitting authority for most discharges within the state EXCEPT for:

EPA is the permitting authority for the Denali National Park and Preserve and Metlakatla Indian Reservation.

The NOI for Alaska projects (through the ADEC) can be filed electronically at Alaska Pollutant Discharge Elimination System Program website. The completed SWPPP will be submitted to either ADEC or the Municipality based on the project type and operator described in the ADEC CGP.

http://dec.alaska.gov/water/wnpspc/stormwater/index.htm http://dec.alaska.gov/water/wnpspc/stormwater/APDESeNOI.html

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Section 2: Project Information

2.1 Project Name and Location

This basic site information is used to file for National Pollutant Discharge Elimination System (NPDES) permit coverage. Permit coverage is obtained by filing the Notice of Intent (NOI) after the SWPPP is complete.

Project Name: Connecting Anchorage Trail Improvements

Project Site Location: Far North Bicentennial Park

City, County, State, Zip Code:

Anchorage, Municipality of Anchorage, Alaska 99503

Latitude/Longitude:

Start of Tour of Anchorage Trail: 61.16509N, -149.77522W Start of North Gasline Trail: 61.170526N, -149.71856W

The method used for determining latitude/longitude was: Other Website getLatLong

Township: Range: Section:

13N 3W 34-36

12N 3W 3

Is the project located in an American Indian or Alaskan Native area?

(previously referred to as Indian Country) No

Are you applying for permit coverage as a “federal operator?” Yes

The project Does Not discharge stormwater into a Municipal Separate Storm Sewer System.

2.2 Project Site Characteristics

The undeveloped site and features of the land that are incorporated into the final soil Erosion and Sediment Control plan sheets (TAB 6), as well as natural resources that should be protected are described below:

Vegetation, trees, and sensitive areas, such as stream buffers, wetlands, highly erodible soils, and steep slopes at the site include:

The park is located along the foothills of the Chugach Mountains. The topography of the project area is generally undulating and hilly, with some areas of steep slopes and lowland wetland complexes. Higher elevations are found moving towards the mountains on the east side of the park.

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The project area consists of native forest and wetlands. Vegetation ranges from wetland vegetation and black spruce to dense forest with cottonwoods, spruce, and birch.

Wetlands surrounding the trail are potential receiving waters throughout the project. The wetlands occurring in the project area were delineated through efforts by PND and divided into five identified areas, including two palustrine wetland areas, two emergent wetland areas, and one forested wetland area. Palustrine wetland occur on either side of the North Fork Campbell Creek at the site of the TOA Trail crossing, and in the areas of the South Fork Campbell Creek. A large swathe of forested wetland area occurs on either side of the TOA Trail at a location south of the South Fork Campbell Creek crossing. Emergent wetlands were identified south of the North Fork Campbell Creek and along the trail near the South Fork Campbell Creek.

Also, see TAB 6.

Stormwater currently drains from the site in the following manner:

Stormwater drains from the site via sheet flow.

Also, see TAB 6.

The location of discharge points or areas:

See above block. Sheet flow will occur across trail areas and into native vegetation.

In areas adjacent to the bridge, storm water will sheet flow will run off the trail/bridge and into North Fork Campbell Creek and South Fork Campbell Creek.

Also see TAB 6

The location of all waters, including wetlands, are shown on the site map located in TABs 5 and 6.

Critical slopes and slope lengths include:

None.

Soil type(s) of highly erodible soils and the soil infiltration capacity are identified as:1

Soils generally consist of peat and silt loams (NRCS 2020b). Minimal change to existing slopes will occur as a result of this project. The project will include widening of some portions of the trail, and in these areas the majority of expansion will require fill, although cut into the existing ground will be required in some areas. In order to minimize potential impacts to waters of the U.S., embankment

1 NRCS Web Soil Survey.

http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx

[5] slopes were steepened as much as possible to minimize project footprints while still maintaining safety and stability. Fill slopes are proposed at 3H:1V with cut slopes at 2H:1V. Other than at the proposed bridge approaches, the embankments throughout the project will be less than 2 feet in height.

Any past soil contamination at the site is identified as:

No historic sources of site contamination have been identified inside the project area. Two sites marked as ‘cleanup complete’ are within 1500 feet of the north end of TOA Trail, and one active site for petroleum contamination exists at the north end of the TOA Trail. Additionally, several sites marked as ‘cleanup complete’ exist along the Campbell Airstrip, at distances exceeding 2000 feet from the TOA Trail improvement activities.

(“Alaska DEC Contaminated Site – ArcGIS”. Alaska DEC Contaminated Sites.

Alaska DEC. Web. 22 September. 2020.)

Site Name Hazard ID Location Status

AKARNG CSMS Lower Yard 3301 61.174428 N, -149.783753 W Active

Southcentral Foundation - Tudor Centre Dr

3906 61.181478 N, -149.796605 W Cleanup Complete

Chugach Electric University Substn. 415 61.179510 N, -149.794652 W Cleanup Complete

Protected Natural Features (natural features include trees, streams, wetlands, slopes, etc.):

See first block under this section. Also see TAB 6.

Measures to protect these features:

Activities related to project construction will be given careful consideration to preserve existing vegetation and to minimize the amount of land disturbed at one time. Project disturbance limits will be clearing marked using fencing, flagging tape, or staking per the requirements of Site Delineation (AK BMP-54). Minimal cutting will be included in this project and native topsoil will be preserved as much as possible for reuse on the project. Topsoil will be stockpiled at the edge of cuts for future use.

Rainfall:

Mean Annual Precipitation at the Project Site (inches):2 15.3

2 NRCS Annual Climate Data https://www.wcc.nrcs.usda.gov/climate/navigate_wets.html

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Frequency, intensity, and duration of rainfall for the project site:

(principal factors influencing erosion from a construction site)

The 2-year, 24-hour storm event:3

1.33 inches/day

The 10-year, 24-hour storm event:

1.97 inches/day

The 25-year, 24-hour storm event:

2.37 inches/day

Approximate Growing Season at the Project Site: May 8-October 5 (Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Alaska Region (Version 2.0), US Army Corps of Engineers).

Approximate Freeze-Up and Spring Thaw Dates at Project Site: August 28 (fall freeze)-May 22 (spring thaw) (Anchorage, Alaska “Fall ‘Freeze’ and Spring ‘Freeze’ Probabilities.” Western Regional Climate Center. Web. 22 September. 2020.)

3 Precipitation frequency for Western States http://www.wrcc.dri.edu/Climate/precip_freq_maps.php

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Section 3: Nature of Construction Activity

3.1 General Description of Project and Scope of Work:

(i.e., highway construction, roadway realignment, highway and bridge reconstruction, etc.):

The project consists of trail improvements in Far North Bicentennial Park (FNBP) in Anchorage, Alaska, and will include specific trail improvements, bridges, and an upgraded wayfinding system. The Tour of Anchorage (TOA) Trail (also known as the Old Rondy Trail) and the North Gasline Trail will be included in this project. Trail improvements will consist of widened tread width, improved surface material, cleared width, and sight distance upgrades.

Bridge improvements will consist of the replacement of three existing bridges on the TOA Trail and one new bridge on the North Gasline Trail.

The type or function of the project is: Other transportation-related – Trail

Construction Support Activities: If applicable, describe any construction support activities, such as dedicated concrete or asphalt batch plants, dedicated aggregate sites, equipment staging yards, material storage areas, borrow, or disposal sites (government-selected sites):

To be completed by contractor

Dedicated

Support Activity Location Yes No

Concrete Batch Plant N/A ☐

Asphalt Batch Plant N/A ☐

Equipment Staging Yards

See maps. Potential staging areas include:

Campbell Airstrip area Parking areas along Science Center

Drive Alaska Department of

Transportation and Public Facilities (ADOT&PF) Maintenance Yard

Ballfields on Dr. Martin Luther King Jr. Avenue

Material Storage Areas

See maps. Potential staging areas include:

Campbell Airstrip area Parking areas along Science Center

Drive Alaska Department of

Transportation and Public Facilities (ADOT&PF) Maintenance Yard

Ballfields on Dr. Martin Luther King Jr. Avenue

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Excavated Material Disposal Areas

Unsuitable material excavated during construction will be immediately hauled off-site to reduce risk of sediment transport.

Borrow Areas No borrow areas are anticipated for this project. ☐

NOTE: All Contractor-selected sources and support sites are the sole responsibility of the General Contractor. The SWPPP and NPDES permitting for Contractor-selected sites and sources are separate from this documentation (SCR 107.01A(h)).

Support activities will be located on the general vicinity map and/or site map in TAB 5 and TAB 6 by the Contractor.

Size of Project Action Area:

(Including all Government-selected support sites such as staging, borrow, waste, access roads, affected downstream area, noise perimeter, extent of light effects, etc.)

Estimated Area Units

Total project area (within outermost project boundary): 3.59 acres

Disturbed project area (area of digging within total project area): 2.7 acres

Percent Impervious Project Area BEFORE Construction: 0.75 % Runoff Coefficient BEFORE Construction: 0.30 %

Percent Impervious Project Area AFTER Construction: 1.8 % Runoff Coefficient AFTER Construction: 0.41 %

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3.2 Sequence and Estimated Dates of Construction Activities

The intended construction sequencing and timing of major construction activities is detailed here, including the phased grading and stabilization activities used to minimize overall amount of disturbed soil.

Contractor and PE Note: Fill in all incomplete information following contract award date and prior to start of construction

Phase:

Construction sequence description: Duration of sequence: BMPs associated with this sequence: Stabilization measures:

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Phase:

Construction sequence description: Duration of sequence: BMPs associated with this sequence: Stabilization measures:

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Phase:

Construction sequence description: Duration of sequence: BMPs associated with this sequence: Stabilization measures:

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Phase:

Construction sequence description: Duration of sequence: BMPs associated with this sequence: Stabilization measures:

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Phase:

Construction sequence description: Duration of sequence: BMPs associated with this sequence: Stabilization measures:

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3.3 Potential Sources of Pollutants

The follow table identifies all potential sources (checked activities in column 1) of sediment and other sources of pollution, which may reasonably be expected to affect the quality of stormwater discharges from the construction site.

Potential Construction Site Pollutants

Se le ct ed

A ct iv ity

(X

Construction Activity

Se di m en t

N ut ri en ts

B ac te ri a pH O il

G re as e

T ra sh

D eb ri s

Pe st ic id es

H ea vy M et al s

O th er

Po llu ta nt s

Clearing, excavating, and grading X X Fill of roadway embankment, backfill at structures X X

Vehicle/equipment fueling and maintenance X X X

Vehicle/equipment use and storage X X

Sanitary/septic waste X X Dewatering operations X X

Drilling and blasting operations X X X Concrete washout and waste X X Structure construction/painting/cleaning X X X X

Demolition and debris disposal X X X X X

Solid waste (trash and debris) X X

Hazardous waste or contaminated spills X X X

Paving operations X X

Landscaping operations X X X Mining, rock extraction, crushing X X X

Contractor and PE Note: Fill in all incomplete information following contract award date and prior to start of construction

Construction and waste material expected to be stored on-site includes:

Material Storage Location

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Section 4: Site Maps

Vicinity maps are located in TAB 5.

Site maps and erosion and sediment control plan maps are located in TAB 6.

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Section 5: Discharges

Industrial stormwater discharges associated with industrial activity other than construction at the site (including dedicated asphalt plants and dedicated concrete plants that are covered by this permit) include:

NOTE: An Industrial Activity Multi-Sector General Permit may be required for some activities.

Industrial Activity Stormwater Discharge Location Multi-Sector General Permit Number (if applicable)

1. N/A

5.1 Allowable Non-Stormwater Discharges

Non-stormwater discharges used at the construction sited are identified below, along with control measures used to eliminate or reduce the discharges and BMPs used to prevent stormwater contamination.

Applicable to this Project

(check all that apply)

Potential Non-Stormwater Discharges Control Measures

To be completed by contractor

Waters used to wash vehicles where detergents are not used Water used to control dust Do not overwater. See also TAB 6.

Potable water including uncontaminated water line flushings Construction dewatering (uncontaminated) Ground water or spring water (uncontaminated) Routine external building wash down that does not use detergents Pavement wash waters where spills or leaks of toxic or hazardous materials have not occurred (unless all spilled material has been removed) and where detergents are not used Foundation or footing drains where flows are not contaminated with process materials such as solvents Landscape irrigation Discharges from emergency fire-fighting activities Fire hydrant flushings Uncontaminated air conditioning or compressor condensate

NOTE: The likely locations of these discharges are identified on the site map TAB 5 and/or

TAB 6

5.2 Receiving Waters:

Are there any surface waters located within 50 feet of the construction disturbance? Yes

Name(s) of the first surface water that receives stormwater directly from your site and/or from the MS4

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1. North Fork Campbell Creek (AWC 247-60-10340-2021)

2. South Fork Campbell Creek (AWC 247-60-10340-2020)

3. Wetlands

4.

Impaired Waters/TDMLs:

Answer the following for each surface water listed in Table 1:

Is this surface water listed as “impaired?”

What pollutant(s) is causing the impairment?

Has a TMDL been completed?

Pollutant(s) for which there is a TDML

1. Yes No Yes No

2. Yes No Yes No

3. Yes No Yes No

4. Yes No Yes No

Source used to determine whether or not your project discharges into an impaired water:

Alaska DEC Water Quality Map

Tier 2, 2.5 or 3 Waters Answer the following for each surface water listed in Table 1:

Is this surface water designated as Tier 1,2 or 3?

If yes, specify which Tier.

1. Yes No Choose an item.

2. Yes No Choose an item.

3. Yes No Choose an item.

4. Yes No Choose an item.

If applicable, documentation of consultation with State or Federal TMDL authorities on consistency of SWPPP conditions with the approved TMDL is found in TAB 11. The control measures required to ensure that discharge of pollutants from the site are consistent with the assumptions and requirements of the EPA-established or approved TMDL, including any specific waste-load allocations are included in that documentation.

5.3 Water Quality Monitoring Requirements

Provisions in Permit Conditions of the applicable NPDES stormwater permit, as well as the associated §401 certification or other special conditions, define additional monitoring and reporting requirements. Details about water quality monitoring and reporting requirements applicable to this project are included in TAB 11.

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Samples and measurements taken for the purpose of monitoring will be representative of the monitored activity. Records of all monitoring information will be retained in TAB 11, including all calibration and maintenance records and all original strip chart recordings for continuous monitoring instrumentation.

Records of monitoring information will include:

1. The date, exact place, and time of sampling or measurements;

2. The individual(s) who performed the sampling or measurements;

3. The date(s) analyses were performed

4. The individual(s) who performed the analyses;

5. The analytical techniques or methods used; and

6. The results of such analyses.

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Section 6: Compliance with Other Applicable Requirements

6.1 Endangered Species Protection

Under which criterion is project eligible for Endangered Species coverage under the NPDES permit (EPA)?

A B C D E F

Criterion A. No federally-listed threatened or endangered species or their designated critical habitat(s) are likely to occur in your site’s “action area” as defined in Appendix A of EPA permit.

Criterion B. The construction site’s discharges and discharge-related activities were already addressed in another operator’s valid certification of eligibility for your action area under eligibility Criterion A, C, D, E, or F and there is no reason to believe that federally-listed species or federally-designated critical habitat not considered in the prior certification may be present or located in the “action area”. To certify your eligibility under this Criterion, there must be no lapse of NPDES permit coverage in the other operator’s certification. By certifying eligibility under this Criterion, you agree to comply with any effluent limitations or conditions upon which the other operator's certification was based. You must include in your NOI the tracking number from the other operator’s notification of authorization under this permit. If your certification is based on another operator’s certification under Criterion C, you must provide EPA with the relevant supporting information required of existing dischargers in Criterion C in the EPA NOI form.

Criterion C Federally-listed threatened or endangered species or their designated critical habitat(s) are likely to occur in or near your site’s “action area,” and your site’s discharges and discharge-related activities are not likely to adversely affect listed threatened or endangered species or critical habitat. This determination may include consideration of any stormwater controls and/or management practices you will adopt to ensure that your discharges and discharge-related activities are not likely to adversely affect listed species and critical habitat. To make this certification, you must include the following in your NOI: 1) any federally listed species and/or designated habitat located in your “action area”; and

2) the distance between your site and the listed species or designated critical habitat (in miles). You must also include a copy of your site map with the NOI.

Criterion D. Coordination between you and the Services has been concluded. The coordination must have addressed the effects of your site’s discharges and discharge-related activities on federally-listed threatened or endangered species and federally-designated critical habitat, and must have resulted in a written concurrence from the relevant Service(s) that your site’s discharges and discharge-related activities are not likely to adversely affect listed species or critical habitat. You must include copies of the

[17] correspondence between yourself and the Services in your SWPPP and

NOI.

Criterion E. Consultation between a Federal Agency and the U.S. Fish and Wildlife Service and/or the National Marine Fisheries Service under section 7 of the ESA has been concluded. The consultation must have addressed the effects of the construction site’s discharges and discharge-related activities on federally-listed threatened or endangered species and federally-designated critical habitat. The result of this consultation must be either:

i. a biological opinion that concludes that the action in question (taking into account the effects of your site’s discharges and discharge-related activities) is not likely to jeopardize the continued existence of listed species, nor the destruction or adverse modification of critical habitat;

or

ii. written concurrence from the applicable Service(s) with a finding that the site’s discharges and discharge-related activities are not likely to adversely affect federally-listed species or federally-designated habitat.

You must include copies of the correspondence between yourself and the Services in your SWPPP and NOI.

Criterion F. Your construction activities are authorized through the issuance of a permit under section 10 of the ESA, and this authorization addresses the effects of the site’s discharges and discharge-related activities on federally-listed species and federally-designated critical habitat. You must include copies of the correspondence between yourself and the Services in your SWPPP and NOI.

Support Documentation: This determination was made based on a review of the United States Fish and Wildlife Service (USFWS), Alaska Department of Fish and Game (ADF&G), and National Marine Fisheries Service (NMFS) websites to determine whether any endangered/threatened species and/or final/proposed critical habitat occurs within or near the project area.

6.2 Historic Preservation

1. Will the project involve installation of any of the following stormwater controls that entail subsurface earth disturbance? Yes

Dike Berm Catch Basin Pond Ditch, trench, swale, perimeter drain, etc.

Culvert Other ground-disturbing stormwater control Click here to enter text.

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If the project involves no installation of earth-disturbing stormwater controls, then no further historic preservation screening is necessary (for NPDES permitting purposes).

2. If answer to step 1 is Yes, have professional surveys or evaluations determined that historic properties do not exist (or have prior disturbances at the site precluded the existence of historic properties)? Yes Provide documentation for the basis of this determination. Click here to enter text.

3. If answer to step 2 is No, have professional surveys or evaluations determined that installation of stormwater controls will have no effect on historic properties? Choose an item.

Provide documentation for the basis of this determination.

4. Has the State Historic Preservation Officer (SHPO), Tribal Historic Preservation Office (THPO) or other tribal representative concurred with the determinations of effects on historic properties? Yes Provide the nature of their response. SHPO has found that the CAT project will have no adverse effect on cultural properties.

6.3 Safe Drinking Water Act Underground Injection Control Requirements

Will the project plan install any of the following controls? No Check all that apply:

Infiltration trenches (if stormwater is directed to any bored, drilled, driven shaft or dug hole that is deeper than is widest surface dimension, or has a subsurface fluid distribution system) Commercially manufactured pre-cast or pre-built proprietary subsurface detention vaults, chambers, or other devices designed to capture and infiltrate stormwater flow.

Drywells, seepage pits, or improved sinkholes (if stormwater is directed to any bored, drilled, driven shaft or dug hole that is deeper than its widest surface dimension, or has a subsurface fluid distribution system)

If yes, provide documentation of communications with the EPA or applicable State agency.

Click here to enter text.

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Section 7: Erosion and Sediment Controls

Note: Contractor and PE – if any additional control methods are put in place, or there are modifications to existing control methods, make notes in this section accordingly Control measures at the construction site are selected, installed, implemented, and maintained to minimize pollutants in the discharge as necessary to meet applicable water quality standards.

The objectives of this SWPPP include:

Stabilize the site as soon as possible (targeting the preparation and implementation of erosion and sediment controls to get the site to final grade, and either permanently or temporarily stabilize all bare soil areas as soon as possible).

Perimeter controls will be installed before ground disturbing activities are initiated.

Perimeter protection will remain in place until final stabilization has been achieved.

Slopes and channels will be protected by conveying concentrated stormwater runoff around the top of slopes and stabilize slopes as soon as possible. Avoid disturbing natural channels and the vegetation along natural channels as much as possible.

Divert stormwater coming on to the site by conveying it safely around, through, or under the work area. (Divert the clean water, trap the dirty water.)

Protect receiving waters and other environmentally sensitive waters or areas adjacent to the site.

Follow pollution prevention measures by providing proper containers for waste and garbage at the site. Store hazardous materials and chemicals so that they are not exposed to stormwater.

Minimize the area and duration of exposed soils. Clear only land that will be under construction in the near future.

7.1 Natural Buffers or Equivalent Sediment Controls (Required for EPA CGP states only – ID, WA)

This section only applies if a surface water is located within 50 feet of the project’s earth disturbing activities.

Are there any surface waters within 50 feet of the project’s earth disturbances? Yes

If No, then no further documentation is required for the SWPPP.

NOTE: Reference EPA CGP appendix G for buffer guidance.

If Yes, check which natural buffer compliance alternative is used at the project site:

The project will provide and maintain a 50-foot wide undisturbed natural buffer.

The location and width of natural buffers are shown on the Erosion and Sediment Control Plan sheets in TAB 6.

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The project will provide and maintain an undisturbed natural buffer that is less than 50 feet in width and is supplemented by additional erosion and sediment controls, which in combination achieves the sediment load reduction equivalent to a 50-foot undisturbed natural buffer.

The location of natural buffers are shown on the Erosion and Sediment Control Plan sheets in TAB 6.

Insert the width of the natural buffer to be retained Vegetative buffers will be delineated as described in 10.1 and shall have a minimum width of 25 feet unless found infeasible.

Insert description of additional erosion and sediment controls to be used in combination with the natural buffer: Compost socks, fiber rolls, and silt fence will be installed as appropriate. See TAB 6.

Document the method used to determine that the above combination of natural buffer and sediment and erosion controls equal the estimated sediment removal capacity of a 50-foot undisturbed natural buffer: The trail is located in a native forest that readily percolates typical rainfall events, which limits the off-site runoff.

It is infeasible to provide and maintain an undisturbed natural buffer of any size, therefore, the project will implement erosion and sediment controls that achieve the sediment load reduction equivalent to a 50-foot undisturbed natural buffer.

Insert rationale for concluding that providing and maintaining a natural buffer of any size is infeasible: Click here to enter text.

Insert description of erosion and sediment controls to be used to achieve the sediment load reduction equivalent to a 50-foot undisturbed natural buffer: Click here to enter text.

The project qualifies for one of the exceptions in EPA CGP Part 2.1.2.1.e For a “linear project”, site constraints (e.g. limited right of way) make it infeasible for the project to meet any of the CGP part 2.1.2.1.a compliance alternatives.

Other exception (state type): Click here to enter text.

Document why it is infeasible to meet one of the buffer compliance alternatives: Click here to enter text.

Insert description of erosion and sediment controls to be used to achieve the sediment load reduction equivalent to a 50-foot undisturbed natural buffer: Click here to enter text.

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7.2 Perimeter Controls

All Perimeter Sediment Controls will be installed prior to ground disturbing activities taking place. There will be no clearing or grubbing outside the physical clearance limits.

Locations and design specifications of BMPs are shown on the erosion and sediment control plan sheets in TAB 6.

The following perimeter controls will be implemented:

Measure: Fiber rolls Implementation: Install prior to earth disturbing activities in the contributing drainage area.

Maintenance: Inspect that rolls are intact, roll ends remain abutted tightly, and that overlap meets minimum requirements. Ensure the rolls are in contact with the soil, staked, and properly entrenched. Inspect for evidence of scouring underneath rolls. If rolls are crushed, torn, slumping, or split, the damaged sections must be replaced. Remove sediment accumulated upslope of the roll when it reaches one half of the above ground height of the roll.

Measure: Silt Fence Implementation: Installed prior to soil disturbance in the contributing drainage area.

Maintenance: Inspect fence line for continuity, collapse, undermined areas, capacity, and damage. Inspect fabric for tears, punctures, fraying, weathering, and compromised integrity.

Confirm fence posts are secure. Ensure fence is keyed into substrate and that there is no undercutting. Look for evidence of sediment or erosion flow leading off the downhill edge of the fence (this may be an indicator of drainage bypass or an undermined fence). Note depth of sediment build up at the fence. Look for signs of inadequate protection of off-site sensitive areas.

Check for sediment flowing through the fence. Check for holes in fence where wire ties are used to secure geotextile fabric to the support post. Install alternate or additional BMPs as needed to prevent undesirable sedimentation of sensitive areas. Replace damaged fabric. Remedy fence sags as needed. Remove accumulated sediment before one third of the available storage. Dispose of silt waste in approved manner/location (typically in a non-erosion area). If there is evidence of excessive sedimentation against the silt fence, provide increased erosion control upslope.

Reinforce fence line as needed to prevent undesirable sedimentation of sensitive areas.

Contractor and PE Note: Add additional measures used during construction.

7.3 Sediment Track-Out

The following methods will be implemented to minimize off-site vehicle tracking of sediment onto paved surfaces. If sediment escapes the construction site, off-site accumulations of sediment will be removed at a frequency sufficient to minimize off-site impacts.

Locations and design specifications of BMPs are shown on the erosion and sediment control plan sheets in TAB 6.

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Measure: Stabilized Construction Exit Implementation: Install stabilized exit prior to earth work.

Maintenance: Inspect stabilized construction exit and ditches for sediment accumulation and material displacement. Inspect roadway for sediment track-out. Maintain each exit in a condition to prevent tracking of mud or sediment into public right-of-way, and remove all mud or sediment deposited on paved roadways. Repair or clean out any structures used to trap sediment.

Contractor and PE Note: Add additional measures used during construction.

7.4 Stockpiled Soil or Other Erodible Materials

Stockpile management includes measures to minimize surface erosion and sediment transport from soil stockpiles or other erodible materials.

Locate erodible stockpiles away from drainages including storm sewer inlets and culvert inlets.

Locations of stockpiles are shown on the erosion and sediment control plan sheets in TAB 6.

☐ Not applicable to this project. Reason: Click here to enter text.

If applicable:

Measure: Silt Fence Implementation: During active construction, if used.

Maintenance: Periodic inspections in accordance with CGP to ensure there is no overtopping, rilling, or other erosive conditions.

Measure: Click here to enter text.

Implementation: Click here to enter text.

Maintenance: Click here to enter text.

Add other measures as needed.

7.5 Minimize Dust

Dust control includes practices used to reduce or prevent the surface and air transport of dust during construction Measure: Dust Control Implementation: As needed throughout construction to control dust from vehicles and wind.

Maintenance: Roads and other bare areas should be moist and free of suspended dust or particulates.

Dust control requires constant attention. It is not a one-time or once-in-awhile activity. Keep haul roads and other bare areas moist by sprinkling with water. Dust control sprinkling may have to be done several times a day during hot, dry weather.

Contractor and PE Note: Add additional measures used during construction.

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7.6 Minimize Disturbance of Steep Slopes

Describe how disturbance of steep slopes will be minimized. Describe controls (e.g. erosion control blankets, tackifiers) that will be implemented to minimize sediment discharges from slope disturbances.

If applicable, describe how stormwater run-on and run-off will be managed. Flows may be diverted from exposed soils by retaining/detaining flows or otherwise minimizing runoff and the discharge of pollutants from exposed areas of the site. Placement of structural practices in floodplains will be avoided to the degree technologically and economically practicable and achievable.

☐ Not applicable to this project. Reason:

Measure: Fiber rolls Implementation: Install prior to earth disturbing activities in the contributing drainage area.

Maintenance: Inspect that rolls are intact, roll ends remain abutted tightly, and that overlap meets minimum requirements. Ensure the rolls are in contact with the soil, staked, and properly entrenched. Inspect for evidence of scouring underneath rolls. If rolls are crushed, torn, slumping, or split, the damaged sections must be replaced. Remove sediment accumulated upslope of the roll when it reaches one half of the above ground height of the roll.

Measure: Temporary Seeding Implementation: Install immediately at areas of the site where construction grading activities have temporarily ceased and are designated for stabilization with seeding mix and mulch.

Maintenance: Ensure coverage is adequate. Ensure area receives adequate water according to the prescribed seeding specifications. Inspect for areas disturbed by foot traffic and/or equipment after installation. Verify seeding is applied during the appropriate seeding window. Apply water to seeded areas as needed according to the seeding specifications. Prepare and reapply seeding mix to areas of disturbed or poor growth to maintain complete coverage, if necessary.

Measure: Permanent Seeding and Soil Amendments Implementation: Install immediately at areas of the site where construction grading activities have permanently ceased and are designated for permanent stabilization with seeding mix and mulch.

Maintenance: Ensure coverage is adequate. Ensure area receives adequate water according to the prescribed seeding specifications. Within 7 days of initial seeding installation continue maintenance with soil amendments (if necessary), additional seeding/mulching, watering, and any other activities to ensure proper vegetative cover is established. Apply water to seeded areas as needed according to the seeding specifications. Prepare soil and reapply seeding mix to areas of disturbed or poor growth to maintain complete coverage, if necessary.

7.7 Topsoil Conservation

Describe how topsoil will be preserved, if feasible. If conservation of topsoil is infeasible, explain why, and describe alternate methods to be used to insure optimum vegetation survival and growth.

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Erosion and sediment control measures for topsoil stockpiles (and other erodible materials) are shown in section 4.4.

Note: Contractor and PE – complete this section as appropriate.

☐ Conservation of topsoil is Infeasible:

Reason: Click here to enter text.

Alternate method: Click here to enter text.

☐ Conservation of topsoil is Feasible:

Measure: Click here to enter text.

Implementation: Click here to enter text.

Maintenance: Click here to enter text.

Measure: Click here to enter text.

Implementation: Click here to enter text.

Maintenance: Click here to enter text.

Add other measures as needed.

7.8 Minimize Soil Compaction

Minimize soil compaction in areas where final vegetative stabilization will occur and where infiltration practices will be installed.

☐ Not applicable to this project. Reason: Click here to enter text.

If applicable:

Measure: Distribute layer of soft vegetative top soil after compaction complete.

Implementation: After soil compaction is complete and prior to revegetation efforts.

Maintenance: Maximize depth whenever possible and seed as soon as practicable. If seeding cannot occur in a timely manner, other BMPs (nets, blankets, etc.) will be placed to mitigate erosion.

Contractor and PE Note: Add additional measures used during construction.

7.9 Storm Drain Inlets and Culvert Inlets

Applicable for stormwater drain inlets which are connected to separate storm sewer systems (usually in urban locations) AND for culvert inlets that discharge stormwater from the project into surface waters.

Locations and design specifications of BMPs are shown on the erosion and sediment control plan sheets in TAB 6.

☒ Not applicable to this project. Reason: No storm drains or culverts.

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7.10 Constructed Stormwater Conveyance Channels and Culvert Outlets

Describe velocity dissipation and/or erosion control devices to be installed at stormwater conveyance channels (such as roadside ditches) and culvert outlets. Includes permanent and temporary devices (specify).

Velocity dissipation devices will be placed at discharge locations and along the length of any outfall channel to provide a non-erosive flow velocity from the structure to a water course so that the natural physical and biological characteristics and functions are maintained and protected (e.g., no significant changes in the hydrological regime of the receiving water).

Locations and design specifications of BMPs are shown on the erosion and sediment control plan sheets in TAB 6.

☒ Not applicable to this project.

7.11 Sediment Basins

If applicable, provide site design specifications and other details for design of sediment basins and ponds. This may also include sediment infiltration swales.

Locations and design specifications of BMPs are shown on the erosion and sediment control plan sheets in TAB 6.

At a minimum, sediment ponds must provide storage for either the calculated volume of runoff from the 2-year, 24-hour storm event or 3,600 cubic feet per acre drained. Sediment ponds must also use outlet structures that withdraw water from the surface, unless infeasible.

☒ Not applicable to this project.

7.12 Chemical Treatment

If chemical sediment control (such as polymers) will be used, provide design specifications and other details considered when choosing treatment type and locations.

☒ Not applicable to this project.

7.13 Dewatering Practices

Discharge of ground water or accumulated stormwater that is removed from excavations, trenches, foundations, etc. into surface waters is prohibited unless such waters are first effectively managed by appropriate sediment controls. Uncontaminated non-turbid dewatering water can be discharge without being routed to a control.

☐ Not applicable to this project

If applicable:

Specific dewatering practice: Temporary Diversion Berm

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Implementation: Installed as required around abutment work area.

Maintenance: Inspect and maintain the temporary diversion berm daily. Repair as needed after rainfall events or as directed. Remove sediment when deposits reach half the height of the sandbag barrier.

7.14 Erosion Control and Stabilization

Commence temporary soil stabilization measures immediately if no further disturbance of an area of the site or stockpile is expected within the next 14 days. Complete temporary soil stabilization measures to disturbed sites or stockpiles within 14 days of last disturbance. Provide for temporary stabilization of all exposed soil prior to winter construction shut down.

Specify whether stabilization measure is temporary or permanent.

☒ Temporary Measures:

Measure: Temporary Seeding Implementation: Install immediately at areas of the site where construction grading activities have temporarily ceased and are designated for stabilization with seeding mix and mulch.

Maintenance: Ensure coverage is adequate. Ensure area receives adequate water according to the prescribed seeding specifications. Inspect for areas disturbed by foot traffic and/or equipment after installation. Verify seeding is applied during the appropriate seeding window. Apply water to seeded areas as needed according to the seeding specifications. Prepare and reapply seeding mix to areas of disturbed or poor growth to maintain complete coverage, if necessary.

Contractor and PE Note: Add additional measures used during construction.

☒ Permanent Measures:

Measure: Permanent Seeding and Soil Amendments Implementation: Install immediately at areas of the site where construction grading activities have permanently ceased and are designated for permanent stabilization with seeding mix and mulch.

Maintenance: Ensure coverage is adequate. Ensure area receives adequate water according to the prescribed seeding specifications. Within 7 days of initial seeding installation continue maintenance with soil amendments (if necessary), additional seeding/mulching, watering, and any other activities to ensure proper vegetative cover is established. Apply water to seeded areas as needed according to the seeding specifications. Prepare soil and reapply seeding mix to areas of disturbed or poor growth to maintain complete coverage, if necessary.

Contractor and PE Note: Add additional measures used during construction.

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7.15 Removal of BMPs

Remove erosion and sediment control BMPs that are no longer needed and leave in good working order those BMPs that will remain at the construction site after close-out.

BMPs are no longer needed when the site that the BMP is protecting has reached final stabilization as defined in the applicable NPDES Stormwater Permit.

Final stabilization means:

All ground disturbing activities at the site have been completed, AND

Vegetation has been established that provides a uniform perennial vegetative cover with a density of 70% of the natural vegetative cover prior to construction.

In arid (0-10” annual precipitation) or semiarid (10-20” annual precipitation) areas, final stabilization is considered to be achieved when the area is seeded or planted and vegetation is expected to provide 70% cover within 3 years; AND, erosion controls are in place that provide soil protection for at least 3 years without active maintenance.

Document arid/semi-arid conditions in SWPPP

Effective non-vegetative stabilization is in-place such as rip rap, gabions, geotextiles, rock, aggregate etc.

7.16 Post Construction Measures

Responsibility for NPDES permit compliance after construction close-out will be the responsibility of:

☒ FHWA/WFLHD

☒ Land Management/Owner Agency Specify Agency: Choose…