S06 - Amendment 0007 Att 2 - Final SWP3.pdf

September 2023

STORM WATER POLLUTION

PREVENTION PLAN

FOR

Chillicothe VA Medical Center

EHRM Infrastructure Upgrades

Chillicothe, OH

GENERAL INFORMATION

All contractors and subcontractors shall conduct their operations in a manner that minimizes erosion and prevents sediments from leaving the project site.

The Prime Contractor of each phase of construction shall be responsible for compliance and implementation of the Stormwater Pollution Prevention Plan (SWP3) for the entire term of their contract. This responsibility shall be further shared with subcontractors whose work is a source of potential pollution as defined in this SWP3. This includes the installation, maintenance, revisions and amendments, inspections and removal.

It is also the responsibility of each Prime Contractor to coordinate compliance and implementation of the SWP3 with the Construction Manager and to provide any revisions and amendments to the Construction Manager with the appropriate signatures and certifications for the inclusion in the master copy of the SWP3. Each Prime Contractor shall perform the required inspections of the respective erosion control measures and provide the completed inspection reports to the construction Manager within 24 hours of the inspection date.

It is the ultimate responsibility of the construction manager to keep the master copy of the SWP3 up to date with all certifications, revisions and amendments, and inspection reports. The master copy of the SWP3 shall be retained at the construction site at all times from the date of project initiation to the date of final stabilization.

GENERAL CONTACT INFORMATION

DEVELOPER/OWNER: VAMC Chillicothe, Ohio

CONTACTS: Mr. Ryan Jeter, Chief Facilities Management Service

Address: 17273 State Route 104, Chillicothe, OH 45601 Phone: (740) 773-1141 ext. 16170

Email: ryan.jeter@va.gov

And

Mr. Jerry Sinclair, Healthcare Engineer

Address: 17273 State Route 104, Chillicothe, OH 45601 Phone: (740) 773-1141 ext. 16887

Email: jerry.sinclair@va.gov

CONSTRUCTION MANAGER

Contractor: ________________________________________

Contact Name: ________________________________________

Address: ________________________________________

Phone Number: ________________________________________

Mobile Number: ________________________________________

SITE IMPROVEMENT

Contractor: _________________________________________

Contact Name: _________________________________________

Address: _________________________________________

Phone Number: _________________________________________

Mobile Number: _________________________________________ mailto:ryan.jeter@va.gov mailto:jerry.sinclair@va.gov

STORMWATER POLLUTION PREVENTION PLAN

CHILLICOTHE VA MEDICAL CENTER

EHRM INFRASTRUCTURE UPGRADES PROJECT

CHILLICOTHE, OHIO

All contractors and subcontractors shall conduct their operation in a manner that minimizes erosion and prevents sediments from leaving the project site. The prime contractor shall be responsible for compliance and implementation of the Stormwater Pollution Prevention Plan

(SWP3) for their entire contract. This responsibility shall be further shared with subcontractors whose work is a source of potential pollution as defined in this SWP3. All contractors and subcontractors are required to the sign the Stormwater Pollution Prevention Plan certification statement page within this SWP3

A copy of this SWP3 must be kept at the construction site at all times. Records must be retained for three years after the date of final stabilization. Plans must be made available upon request from the Ohio EPA and other regulatory authorities.

1. SITE DESCRIPTION

This Stormwater Pollution Prevention Plan (SWP3) is for earthwork activities that include trenching and final grading associated with the installation of a fiber optic utility line project.

Construction at the site includes pavement removal/replacement, trenching activities, concrete vault installation/construction with fiber optic placement inside, backfilling/final soil grading and seeding. The project also includes fiber connection to buildings on the property. Following completion of construction work, any construction entrance area gravel areas, materials storage or staging areas if used, shall be removed, reseeded, and restored back to pre-construction conditions.

The site is located throughout the property addressed at 17273 State Route 104 in the City of

Chillicothe, Ross County, Ohio.

This SWP3 covers approximately 4.4 acres with an estimated 4.4 acres being disturbed throughout the medical center property.

The project site is located mainly in an area that is mapped as Kendallville silt loam from 2 to 6 percent slopes (in general the approximate western half of the property). The eastern approximate half of the project site area is mapped as Eldean loam from 0 to 6 percent loam. A small area at the northwest corner of the site and areas along the western site boundary are mapped as Miamian silt loam from 2 to 6 percent slopes along with 6 to 12 percent slopes, eroded. The estimated average runoff coefficient for this site after completion will be 0.50 (based on Rational Method). A copy of the NRCS Soil Map is attached at the end of the SWP3 document section.

Refer to the plan drawings (which serves as the SWP3 required Site Map) for site grading elevations, surface grades/slopes, soil disturbance areas, storm water drainage, soil erosion control methods, and surface water features (if applicable). A copy of these plans will be available at the site. Due to the large and long linear nature of this project, the final runoff from this work will flow in all directions throughout the site where trench excavation is proposed. A majority of the storm water will be allowed to flow over the grass vegetated surface and either infiltrate into the ground or eventually be directed into the existing storm sewer system. Overall, the majority of the storm water shall be directed in a south/southeasterly direction and off the project site. Final flow shall continue to be directed in a south/southeasterly direction and eventually empty into the Scioto River, which is the nearest major waterway.

Potential sources of pollution:

Site sources of pollution generated as a result of this work relate to silt and sediment, concrete, washout, dumpsters, equipment fueling, and portapoties.

2A. CONTROLS AND SEQUENCE OF MAJOR ACTIVITIES

Phase I – Due to the narrow linear scope of this proposed project and the anticipated limited heavy equipment traffic, no construction entryway is proposed. The contractor shall determine if

Due to the limited room along with the developed surrounding site area, and minimal exterior concrete use proposed, no concrete washout shall be constructed. If any concrete pouring is proposed, all truck washout shall be performed back at the facility.

Phase II - Prior to beginning demolition, grading, excavation, or clearing and grubbing operations: initial silt control shall be placed on the boundary of the excavated areas where needed. In particular perimeter controls shall be placed at locations where there is a 3:1 slope or greater and placed on the down slope and side slope areas. In addition, silt control shall be placed downgradient along the perimeter of the excavation area in the drainage ditch and on the upgradient end of the flared-end section structure (downstream end) within the ditch where trenching is proposed (southeast region of the site). Lastly, silt control shall be placed around all existing inlets within the vicinity and downgradient from the excavated areas of the project. It is the contractor’s responsibility to assess the project site area and placement location of all silt control devices that will provide the best sediment control without interfering with their work.

Do not disturb any area until it is necessary for construction.

Phase III - Following completion of utility installation, backfilling and final grading shall occur.

Cover and stabilize disturbed areas as soon as possible following final topsoil placement with final seeding/straw cover or sodding. All trenches shall be backfilled after each day prior to contractor leaving the site.

If construction activities are not planned to occur in a disturbed area or suspended for at least 14 days, the area shall be stabilized by temporary seeding and mulching within 7 days (see section

2C for temporary stabilization specifications). The contractor shall time construction activities to limit impact from seasonal climate changes or weather events.

As construction activities progress, additional erosion control items may be required as determined by the owner, inspector, or regulatory authority after field investigations. The contractor will complete construction operations with the establishment of permanent perennial vegetation of all disturbed areas. Control methods are to remain in place and operational until upstream areas have reached final stabilization.

This work shall be done in accordance with the Ohio Environmental Protection Agency’s

Rainwater and Land Development Manual. Reference control method specifications/details at the end of the SWP3.

CONSTRUCTION

ACTIVITY

APPROX.

START DATE

CONTROL MEASURE

EARTHWORK

VARY BY

STAGE

SILT CONTROL – Placed on the excavated trench perimeters where needed, on the downgradient side near the drainage ditch, & near the upgradient end of the flared-end section within the ditch where trenching is proposed (southeast region of the site).

INLET PROTECTION – Placed around all existing inlets in the vicinity of excavation.

TEMPORARY SEEDING – If applicable.

DEMOLITION

VARY BY

STAGE

N/A

PAVING

CONCRETE WASHOUT – None proposed due to minimal concrete use. All washout shall occur at the facility

FINAL GRADING

STAGE

TOPSOIL PLACEMENT (See Below)

TEMPORARY SEEDING (See Below) –

If applicable.

LANDSCAPING

VARY BY

FINAL SODDING – If applicable.

2B. TOPSOIL PRESERVATION

Unless infeasible, meaning “not technologically possible, or not economically practicable and achievable in light of the best industry practices”, the permittee(s) shall minimize soil compaction and preserve all topsoil. Topsoil preservation shall mean that “topsoil from any area of the site where the surface of the ground for the permitted construction activities is disturbed, shall remain within the area covered by the applicable Ohio EPA General Permit No. OHC-000006 authorization. Preserving topsoil is not required where the intended function of a specific area of the site dictates that the topsoil be disturbed or removed”.

2C. SEEDING FOR STABILIZATION

If temporary seeding is required or final seeding is proposed for stabilization, the contractor shall use the following the stabilization guidelines established by the Ohio EPA’s Soil Stabilization practices for the proposed temporary and permanent seeding associated with the proposed project.

Table 1: Permanent Stabilization

Area requiring permanent stabilization Time frame to apply erosion controls

Any areas that will lie dormant for one year or more

Within seven days of the most recent disturbance

Any areas within 50 feet of a surface water of the state and at final grade

Within two days of reaching final grade

Other areas at final grade Within seven days of reaching final grade within that area

Spring and summer seeding

Table 2: Temporary Stabilization

Area requiring temporary stabilization Time frame to apply erosion controls

Any disturbed areas within 50 feet of a surface water of the state and not at final grade

Within two days of the most recent disturbance if the area will remain idle for more than 14 days

Any disturbed areas that will be dormant for more than 14 days but less than one year, and

Within seven days of the most recent disturbance area not within 50 feet of a surface water of the state

For residential subdivisions, disturbed areas must be stabilized at least seven days prior to transfer of permit coverage for the individual lot(s).

Disturbed areas that will be idle over winter Prior to the onset of winter weather

Where vegetation stabilization techniques may cause structural instability or are otherwise unobtainable, alternative stabilization techniques must be employed.

Permanent and temporary stabilization are defined in Part VII.

FINAL STABILIZATION

Practices to reach final stabilization in all disturbed areas is to be by seeding or the placement of sod.

The site will have achieved final stabilization (as defined by the Ohio EPA’s NPDES General

Permit No. OHC-000006) when all soil disturbing activities at the site have been completed, and that a uniform perennial vegetation cover of 70% of the cover for the unpaved areas not covered by permanent structures or that employ equivalent permanent stabilization measures.

Within 45 days after a construction site has undergone final stabilization, temporary erosion control BMPs have been removed and all land disturbing construction activities that required coverage under this permit have ceased, the permittee shall submit a signed Notice of

Termination (NOT) to the Ohio EPA.

2D. STORM WATER MANAGEMENT

A majority of the storm water will be allowed to flow over the grass vegetated surface and either infiltrate into the ground or eventually be directed into the existing storm sewer system. Overall, the majority of the storm water shall be directed in a south/southeasterly direction and off the project site. Final flow shall continue to be directed in a south/southeasterly direction and eventually empty into the Scioto River, which is the nearest major waterway.

No new storm water management/post construction BMP feature is proposed. Due to the type of proposed project (linear utility line installation) with no proposed additional impervious area, no post-construction stormwater management requirements are required. It is noted that the pre and post-construction conditions and runoff shall be similar. The vegetation regions, storm sewer system, drainage ditch area, and Scioto River shall be maintained and reserved throughout the construction process through the use of the previously mentioned best management practices until final stabilization on site is complete.

2E. OTHER CONTROLS

Contractor disposal of unused construction materials and construction material wastes shall comply with applicable state and local waste disposal, sanitary sewer, or septic system regulations. In the event of a conflict with other governmental laws, rules and regulations, the more restrictive laws, rules or regulations shall apply.

Contractor shall treat or dispose of sanitary sewer wastes in accordance with applicable state and local regulations. In the event of a conflict with other governmental laws, rules and regulations, the more restrictive laws, rules or regulations shall apply.

Contractor shall prevent offsite tracking of sediments and generation of dust. Street sweeping shall be performed as needed at the location where vehicles leave the construction zone and throughout the construction area. Contractor must implement dust control measures such as irrigation, if needed.

Discharges from dewatering activities, including discharges from dewatering of pits/trenches and excavations, are allowed provided that the dewatering is treated in accordance with the EPA’s dewatering practices outlined in Part III.G.2.g.iv of the General Permit No. OHC-000006.

Approved state or local plans:

During the course of this construction, it is possible that situations will arise where unknown materials will be encountered. When such situations are encountered, they will be handled according to all federal, state, and local regulations in effect at the time.

3. MAINTENANCE

The contractor is required to maintain all temporary erosion control measures in proper working order, including cleaning, repairing or replacing them throughout the contract period. Cleaning of silt control devices shall begin when the features have lost 50% of their capacity.

4. INSPECTIONS

Inspections shall be made by “qualified inspection personnel” every seven calendar days and within 24 hours following a 0.5” or greater rain event. The findings of this inspection shall be recorded in inspection report. The contractor shall complete repairs or maintenance within 3 days of the inspection. Sediment settling ponds shall be repaired or maintained within 10 days of the inspection. The SWP3 may be revised based on the findings of the inspection. The contractor shall implement all revisions.

5. NON-STORM DISCHARGES

This includes subsurface drains (i.e. longitudinal and standard sub-drains), slope -drains and bridge end drains. The velocity of the discharge from these features may be controlled by the use of patio blocks, class a stone, erosion stone, or scour mats.

6. SPECIAL NON-STORM DISCHARGES

There are no special non-storm water discharges on the site. However, during the course of this construction, it is possible that situations will arise where unknown materials will be encountered.

When such situations are encountered, they will be handled according to all federal, state, and local regulations in effect at the time. The more restrictive laws, rules or regulations shall apply.

Contractor shall report releases of reportable quantities of oil or other hazardous material.

A) Notify the VA Fire/Rescue/HazMat Emergency immediately at 1-740-773-1141 ext. 17161 or 444 from a VA owned phone.

B) Modify SWP3 to include the date of release, circumstances leading to the cause of the release, and steps taken to prevent reoccurrence of the release.

7. REVISIONS

Document all revisions to this SWP3 on the table below.

REVISIONS

DATE DESCRIPTION

8. CONTRACTOR CERTIFICATION

Contractor/subcontractor(s) shall sign the following certification statement.

G:\2022\22003180.00\Design\Civil\_Permits\NPDES\SWP3.doc

STORM WATER POLLUTION PREVENTION PLAN

PROJECT NAME: Chillicothe VA Medical Center EHRM Infrastructure Upgrades

ALL CONTRACTORS AND SUBCONTRACTORS PERFORMING WORK ON THE PROJECT SHALL READ AND SIGN THE CERTIFICATION STATEMENT BELOW. CONTRACTORS SHALL BE CONSIDERED A CO-PERMITTEE FROM THE BEGIN WORK DATE. CONTRACTORS SHALL SIGN AND DATE THE END WORK DATE COLUMN WHEN THE CONTRACTORS ENTIRE SCOPE OF WORK HAS BEEN COMPLETED. CONTRACTORS ARE NO LONGER CONSIDERED CO-PERMITTEES AFTER THE END WORK DATE. PERMITTEE SHALL SEND A NOTICE OF DISCONTINUATION AT THE COMPLETION OF

FINAL STABILIZATION.

I CERTIFY UNDER PENALTY OF LAW THAT I UNDERSTAND THE TERMS AND CONDITIONS OF THE GENERAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT THAT AUTHORIZES THE STORM WATER DISCHARGES ASSOCIATED WITH INDUSTRIAL ACTIVITY FROM THE CONSTRUCTION SITE AS PART OF THIS CERTIFICATION.

FURTHER, BY MY SIGNATURE, I UNDERSTAND THAT I AM BECOMING A CO-PERMITTEE, ALONG WITH THE OWNER AND OTHER CONTRACTORS AND SUBCONTRACTORS SIGNING SUCH CERTIFICATIONS, TO THE OHIO ENVIRONMENTAL PROTECTION AGENCY’S NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) GENERAL PERMIT NO.

OHC-000006 FOR “STORM WATER DISCHARGE ASSOCIATED WITH INDUSTRIAL ACTIVITY FOR CONSTRUCTION ACTIVITIES” AT THE IDENTIFIED SITE. AS A CO-PERMITTEE, I UNDERSTAND THAT I, AND MY COMPANY, ARE LEGALLY REQUIRED UNDER THE CLEAN WATER ACT AND THE CODE OF THE EPA, TO ENSURE COMPLIANCE WITH THE TERMS AND CONDITIONS OF THE STORM WATER POLLUTION PREVENTION PLAN DEVELOPED UNDER THIS NPDES PERMIT

AND THE TERMS OF THE GENERAL NPDES PERMIT.

I CERTIFY UNDER PENALTY OF LAW THAT THIS DOCUMENT AND ALL ATTACHMENTS WERE PREPARED UNDER MY DIRECTION OR SUPERVISION IN ACCORDANCE WITH A SYSTEM DESIGNED TO ASSURE THAT QUALIFIED PERSONNEL PROPERLY GATHERED AND EVALUATED THE INFORMATION SUBMITTED. BASED ON MY INQUIRY OF THE PERSON OR PERSONS WHO MANAGE THE SYSTEM, OR THOSE PERSONS DIRECTLY RESPONSIBLE FOR GATHERING THE INFORMATION, THE INFORMATION SUBMITTED IS, TO THE BEST OF MY KNOWLEDGE AND BELIEF, TRUE, ACCURATE, AND COMPLETE. I AM AWARE THAT THERE ARE SIGNIFICANT PENALTIES FOR SUBMITTING FALSE INFORMATION, INCLUDING THE POSSIBILITY OF FINE AND IMPRISONMENT FOR KNOWING VIOLATIONS.

CONTRACTOR NAME, MAILING ADDRESS, &

TELEPHONE NO.

BEGIN

WORK

DATE

SIGNATURE

PRINTED NAME AND

TITLE

END

WORK

DATE

SIGNATURE PRINTED

NAME AND TITLE

BEGIN

WORK

DATE

SIGNATURE

PRINTED NAME AND

TITLE

END

WORK

DATE

BEGIN

WORK

DATE

SIGNATURE

PRINTED NAME AND

TITLE

END

WORK

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Soil Map—Ross County, Ohio (Chillecothe VA Medical Center)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/18/2023

325500 325600 325700 325800 325900 326000 326100 326200 326300 326400 326500

325500 325600 325700 325800 325900 326000 326100 326200 326300 326400 326500

39° 23' 35'' N

' 3 5'

' W 39° 23' 35'' N

' 5 0'

' W

39° 22' 49'' N

' 3 5'

' W

39° 22' 49'' N

' 5 0'

' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84 0 300 600 1200 1800

Feet 0 100 200 400 600

Meters Map Scale: 1:6,970 if printed on A portrait (8.5" x 11") sheet.

Soil Map may not be valid at this scale.

MAP LEGEND MAP INFORMATION

Area of Interest (AOI) Area of Interest (AOI)

Soils Soil Map Unit Polygons

Soil Map Unit Lines

Soil Map Unit Points

Special Point Features Blowout

Borrow Pit

Clay Spot

Closed Depression

Gravel Pit

Gravelly Spot

Landfill

Lava Flow

Marsh or swamp

Mine or Quarry

Miscellaneous Water

Perennial Water

Rock Outcrop

Saline Spot

Sandy Spot

Severely Eroded Spot

Sinkhole

Slide or Slip

Sodic Spot

Spoil Area

Stony Spot

Very Stony Spot

Wet Spot

Other

Special Line Features

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:15,800.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map measurements.

Source of Map: Natural Resources Conservation Service Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Ross County, Ohio Survey Area Data: Version 23, Sep 12, 2022

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Aug 30, 2020—Sep 26, 2020

The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Soil Map—Ross County, Ohio (Chillecothe VA Medical Center)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/18/2023

Map Unit Legend

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

CgB Celina silt loam, 2 to 6 percent slopes

0.2 0.1%

EeA Eldean loam, 0 to 2 percent slopes

8.7 4.8%

EeB Eldean loam, 2 to 6 percent slopes

57.7 32.0%

EeC2 Eldean loam, 6 to 12 percent slopes, eroded

2.4 1.3%

EgA Eldean gravelly loam, 0 to 2 percent slopes

2.9 1.6%

Ge Gessie silt loam, occasionally flooded

6.3 3.5%

KeB Kendallville silt loam, 2 to 6 percent slopes

68.4 38.0%

MgA Mentor silt loam, gravelly substratum, 0 to 2 percent slopes

3.4 1.9%

MhB Miamian silt loam, 2 to 6 percent slopes

7.1 3.9%

MhB2 Miamian silt loam, 2 to 6 percent slopes, eroded

0.1 0.0%

MhC2 Miamian silt loam, 6 to 12 percent slopes, eroded

11.7 6.5%

MhD2 Miamian silt loam, 12 to 18 percent slopes, eroded

1.0 0.6%

MhE Miamian silt loam, 20 to 35 percent slopes

9.0 5.0%

RdD2 Rodman gravelly loam, 12 to 20 percent slopes, eroded

1.3 0.7%

Totals for Area of Interest 180.1 100.0%

Soil Map—Ross County, Ohio Chillecothe VA Medical Center

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

9/18/2023

STORM WATER POLLUTION PREVENTION INSPECTOR’S REPORT

Inspection of disturbed areas to be completed by qualified personnel once every 7 days and within 24 hours of the end of a storm of 0.5 inches or greater.

Date Time Weather Conds.

Project Name

Construction Phase

Name of Inspector

Qualifications of Inspector

Area Inspected/Description of Work

Date of Last Rain Rain Fall Amount (in.)

Have recommendations from previous inspection been implemented? yes no

Evidence of, or potential of pollutants entering drainage system? yes no (areas of material storage)

Are erosion control devices operating correctly? yes no (silt fences/ditch checks, etc.)

Do erosion controls appear effective? yes no (upon inspection of discharge points)

Is evidence of off-site sediment tracking present? yes no (at locations of access/egress to site)

Affirmative answers to the above questions shall be supplemented with a discussion below

Comments/Discussion

Recommended Corrective Action and/or Modifications to SWPPP

CERTIFICATION

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Signature

Printed Name

Title

Date

CHAPTER 6 Sediment Controls 29

6.3 Silt Fence

Silt fence is a sediment-trapping practice utilizing a geotextile fence, topography and sometimes vegetation to cause sediment deposition. Silt fence reduces runoff’s ability to transport sediment by ponding runoff and dissipating small rills of concentrated flow into uniform sheet flow. Silt fence is used to prevent sediment-laden sheet runoff from entering into downstream creeks and sewer systems.

Silt fence is used where runoff occurs as sheet flow or where flow through small rills can be converted to sheet flow. Major factors in its use are slope, slope length, and the amount of drainage area from which the fence will capture runoff. Silt fence cannot effectively treat flows in gullies, ditches or channels. For concentrated flow conditions see specifications for temporary diversions, sediment traps and sediment basins.

Alternatives: Silt Fence vs. Temporary Diversions and Settling Ponds. While silt fence requires less space and disturbs less area than other control measures there are significant disadvantages to its use. Silt fence is not as effective controlling sediment as routing runoff through a system of diversions and settling ponds. Settling ponds and earth diversions are more durable, easier to construct correctly and significantly more effective at removing sediments from runoff. Additionally earth diversions and settling ponds are less apt to fail during construction and typically require less repair and maintenance.

Description

Conditions Where Practice applies

Planning Considerations

30 CHAPTER 6 Sediment Controls

Proper installation is critical. Experience from ODNR and other field testing has shown that nearly 75 percent of silt fence does not function properly due to poor installation.

Proper installation consists of it being installed: (1) on the contour; (2) with sufficient geo-textile material buried; (3) with the fence pulled taut and supported on the downstream side by strong posts: (4) and with the fence backfilled and compacted.

Two general methods are used to install silt fence: (1) utilizing traditional method of dig-ging the trench, installation of the fence materials, then backfilling and compaction; or (2) a method using an implement to static slice or narrow plow while installing the geotextile in the slot opening, followed by compaction and installation of posts. The latter methods generally installs silt fence more effectively and efficiently.

Silt fence is most applicable for relatively small areas with flat topography. Silt fence should be used below areas where erosion will occur in the form of sheet and rill erosion.

For moderately steep areas, the area draining to the silt fence should be no larger that one quarter acre per 100 feet of fence length, the slope length no longer than 100 feet, and the maximum drainage gradient no steeper than 50 percent (2:1). This practice should be sited so that the entire fence ponds runoff and facilitates settling of suspended solids.

Proper installation of silt fence requires utilizing the site topography. This is critical because the sediment removal process relies on ponding runoff behind the fence. As a ponding occurs behind the fence, coarser materials are allowed to settle out. Leaving a long, flat slope behind the silt fence maximizes areas for ponding (sediment deposition), and for water to disperse and flow over a much larger surface area of the silt fence. For silt fence to work effectively, runoff must be allowed to maintain sheet flow, to pond and to be released slowly. However, if silt fence is used without regard to a site’s topography, it will typically concentrate runoff, increasing the likelihood of blocking and overtopping of the fence, thus reducing or eliminating its effectiveness.

Level Contour – For silt fence to promote deposition, it must be placed on the level con-tour of the land, so that flows are dissipated into uniform sheet flow that has less energy for transporting sediment. Silt fence should never concentrate runoff, which will result if it is placed up and down slopes rather than on the level contour.

Figure 6.3.1 Silt fence layout

Design Criteria

CHAPTER 6 Sediment Controls 31

Flat Slopes – Slope has the greatest influence on runoff’s ability to transport sediment, therefore silt fence should be placed several feet away from the toe of a slope if at all possible, to encourage deposition. Silt fence generally should be placed on the flattest area available to increase the shallow ponding of runoff and maximize space available for deposited sediment.

Flow Around Ends – To prevent water ponded by the silt fence from flowing around the ends, each end must be constructed upslope so that the ends are at a higher elevation.

Vegetation – Dense vegetation also has the effect of dissipating flow energies and causing sediment deposition. Sediment-trapping efficiency will be enhanced where a dense stand of vegetation occurs for several feet both behind and in front of a silt fence.

Maximum Slope Length Above Silt Fence

Slope Slope Length (ft.)

0% - 2% Flatter than 50:1 250

2% - 10% 50:1 - 10:1 125

10% - 20% 10:1 - 5:1 100

20% - 33% 5:1 - 3:1 75

33% - 50% 3:1 - 2:1 50

> 50% > 2:1 25

Note: For larger drainage areas, see standards for temporary diversions, sediment traps and sediment basins.

Table 6.3.1 Maximum area contributing area using slope length

Figure 6.3.2 Silt fence and allowable drainage area

32 CHAPTER 6 Sediment Controls

Dispersing Flow – Proper applications of silt fence allow all the intercepted runoff to pass as diffused flow through the geotextile. Runoff should never overtop silt fence, flow around the ends, or in any other way flow as concentrated flow from the practice. If any of these failures occurs, an alternative silt fence layout, or other practices are needed.

In cases where additional support of the fabric is needed, either wire or geogrid fencing may be used as a backing on the fabric. In these instances, the reinforcing material should be attached/erected first, then the fabric installed.

Materials Fence posts shall be a minimum length of 32 inches long, composed of nominal dimen-sioned 2-by-2-inch hardwood of sound quality. They shall be free of knots, splits and other visible imperfections which would weaken the posts. Steel posts may be utilized in place of wood provide the geotextile can be adequately secured to the post.

Silt fence geotextile must meet the minimum criteria shown in the table below.

Minimum criteria for Silt Fence Fabric (ODOT, 2002)

Minimum Tensile Strength 120 lbs. (535 N) ASTM D 4632

Maximum Elongation at 60 lbs 50% ASTM D 4632

Minimum Puncture Strength 50 lbs (220 N) ASTM D 4833

Minimum Tear Strength 40 lbs (180 N) ASTM D 4533

Apparent Opening Size ≤ 0.84 mm ASTM D 4751

Minimum Permittivity 1X10-2 sec.-1 ASTM D 4491

UV Exposure Strength Retention 70% ASTM G 4355

Silt Fence requires regular inspection and maintenance to insure its effectiveness. Silt fences must be inspected after each rainfall and at least daily during prolonged rainfall. Silt fence found damaged or improperly installed shall be replaced or repaired immediately.

Sediment deposits shall be routinely removed when they reach approximately one-half the height of the silt fence.

The predominant problems with silt fence regard inadequate installation or location that allows runoff to concentrate, overtop the fence, flow under the fabric or around the fence ends. If this occurs one of the following shall be performed, as appropriate:

• The location and layout of the silt fence shall be changed to conform to the level contour

• The silt fence shall be reinstalled with proper burial, backfill and compaction and support

• Accumulated sediment shall be removed

• Alternative practices shall be installed.

Construction and Material Specifications, January 1, 2002. State of Ohio Department of Transportation, P.O. Box 899, Columbus, Ohio 43216-0899, http://www.dot.state.oh.us/ construction/OCA/Specs/2002CMS/Specbook2002/Specbook2002.htm

Maintenance

Common Problems/Concerns

References

Table 6.3.2

CHAPTER 6 Sediment Controls 33

Specifications for

Silt Fence

34 CHAPTER 6 Sediment Controls for

Silt Fence

1. Silt fence shall be constructed before upslope land distur-bance begins.

2. All silt fence shall be placed as close to the contour as possible so that water will not concentrate at low points in the fence and so that small swales or depressions that may carry small concentrated flows to the silt fence are dissipated along its length.

3. Ends of the silt fences shall be brought upslope slightly so that water ponded by the silt fence will be prevented from flowing around the ends.

4. Silt fence shall be placed on the flattest area available.

5. Where possible, vegetation shall be preserved for 5 feet (or as much as possible) upslope from the silt fence. If vegetation is removed, it shall be reestablished within 7 days from the installation of the silt fence.

6. The height of the silt fence shall be a minimum of 16 inches above the original ground surface.

7. The silt fence shall be placed in an excavated or sliced trench cut a minimum of 6 inches deep. The trench shall be made with a trencher, cable laying machine, slicing machine, or other suitable device that will ensure an adequately uniform trench depth.

8. The silt fence shall be placed with the stakes on the downslope side of the geotextile. A minimum of 8 inches of geotextile must be below the ground surface. Excess material shall lay on the bottom of the 6-inch deep trench.

The trench shall be backfilled and compacted on both sides of the fabric.

9. Seams between sections of silt fence shall be spliced together only at a support post with a minimum 6-in.

overlap prior to driving into the ground, (see details).

10. Maintenance—Silt fence shall allow runoff to pass only as diffuse flow through the geotextile. If runoff over-tops the silt fence, flows under the fabric or around the fence ends, or in any other way allows a concentrated flow discharge, one of the following shall be performed, as appropriate: 1) the layout of the silt fence shall be changed, 2) accumulated sediment shall be removed, or

3) other practices shall be installed.

Sediment deposits shall be routinely removed when the deposit reaches approximately one-half of the height of the silt fence.

Silt fences shall be inspected after each rainfall and at least daily during a prolonged rainfall. The location of existing silt fence shall be reviewed daily to ensure its proper location and effectiveness. If damaged, the silt fence shall be repaired immediately.

Criteria for silt fence materials

1. Fence post – The length shall be a minimum of 32 inches.

Wood posts will be 2-by-2-in. nominal dimensioned hardwood of sound quality. They shall be free of knots, splits and other visible imperfections, that will weaken the posts. The maximum spacing between posts shall be 10 ft. Posts shall be driven a minimum 16 inches into the ground, where possible. If not possible, the posts shall be adequately secured to prevent overturning of the fence due to sediment/water loading.

2. Silt fence fabric – See chart below.

FABRIC PROPERTIES VALUES TEST METHOD

Minimum Tensile Strength 120 lbs. (535 N) ASTM D 4632

Maximum Elongation at 60 lbs 50% ASTM D 4632

Minimum Puncture Strength 50 lbs (220 N) ASTM D 4833

Minimum Tear Strength 40 lbs (180 N) ASTM D 4533

Apparent Opening Size ≤ 0.84 mm ASTM D 4751

Minimum Permittivity 1X10-2 sec.-1 ASTM D 4491

UV Exposure Strength Retention 70% ASTM G 4355

Table 6.3.2 Minimum criteria for Silt Fence Fabric (ODOT, 2002)

CHAPTER 6 Sediment Controls 35

Storm drain inlet protection devices remove sediment from storm water before it enters storm sewers and downstream areas. Inlet protection devices are sediment barriers that may be constructed of washed gravel or crushed stone, geotextile fabrics and other materi-als that are supported around or across storm drain inlets.

Inlet protection is installed to capture some sediment and reduce the maintenance of storm sewers and other underground piping systems prior to the site being stabilized. Due to their poorer effectiveness, inlet protection is considered a secondary sediment control to be used in conjunction with other more effective controls.

Storm drain inlet protection is applicable anywhere construction site runoff may enter closed conveyance systems through storm sewer inlets. Generally inlet protection is lim-ited to areas draining less than 1 acre.

This practice is generally not recommended as a primary means of sediment control. Storm drain inlet protection has limited capacity to control silts and clays, and is most effective in capturing larger sand-sized particles. It should only be a primary means if it is not possible to divert the storm drainage to a sediment trap or sediment basin, or if it is to be used only for a short period of time during the construction process.

6.4 Storm Drain Inlet Protection

Description

Condition Where Practice Applies

36 CHAPTER 6 Sediment Controls

Inlet protection in effect blocks storm drain inlets. Therefore consider the effect of ponding muddy water on streets and nearby areas and plan accordingly. Although ponding is benefi-cial in the sediment removal process, this may pose hazardous conditions for street travel.

Additional ponding capacity with related increase in effectiveness can be provided for some drop inlets by excavating around the inlet.

Utilizing inlet protection on long sloping streets may cause runoff to bypass inlets on the slope and cause extra water to accumulate in low areas. In order for the inlet protection to work ponding must be maintained at the practice.

The recommended geotextiles are suitable for retaining/trapping large particle size materi-als, such as sand while maintaining some flow. Only specialized geotextile materials are suitable for retaining clay, silt and other fine soils. These materials, however, are subject to clogging.

Apply storm drain inlet protection as soon as the surface inlet is capable of receiving storm water. Geotextiles utilized in inlet protection are manufactured to control the rate of storm water flow, to retain certain sizes of soil particles. The controlled flow and ponding assists in sediment deposition. Geotextile fabrics come in a variety of materials with permeability, strength and durability ratings. In all cases, follow the manufacturer’s recommendations for the specific product application, as well as installation and maintenance requirements.

All inlet protection practices require frequent maintenance and cleaning to maintain suffi-cient flow rates and to prevent accumulation of mud on streets and other areas.

The following types of storm drain inlet protection are listed according to type of flows and situations where they will perform best. Note that straw bales are not suitable as storm drain inlet protection, since they are often cease to allow flow through once saturated and often leak where bales join. Different types of storm drain inlet protection available are as follows:

A. Excavated Drop Inlet Sediment Trap. Where the storm sewer can be left below the final grade, a depression in the ground adjacent to the inlet can be an effective way of reduc-ing sediment going to the storm sewer. Runoff is directed to the depression and a sedi-ment barrier is maintained between the depression and the storm sewer.

B. Geotextile Inlet Protection. This method consists of placing filter fence around the perimeter of the drop inlet and backfilling. Apply this method where the inlet drains overload flow or sheet flow from gentle slopes and sheet or overland flow.

C. Geotextile-Stone Protection. These are used both on drop inlets and in street curbs and gutters where the ponding of water will not cause damage or inconvience. This filter is simply constructed of geotextile materials over the inlet, with stone on top. Note: this practices does not have an opening for overflow and should not be placed where clog-ging and subsequent flooding would cause safety concerns or property damage.

D. Geotextile-Stone Curb Inlet Protection. This method is used only on curb and gutter inlets and utilizes wire mesh, geotextile and stone over a wood frame. This practice should be used to prevent larger volumes of water from ponding in the street. If the overflow provided is insufficient, it may be modified according to this specification to accommodate greater flows.

CHAPTER 6 Sediment Controls 37

E. Block and Gravel Drop Inlet Protection. This practice utilizes a wall of cement blocks overlain with wire mesh and gravel around the perimeter to slow runoff before entering a storm drain. It is not recommended anywhere vehicle traffic will be operating.

F. Manufactured Inlet Protection Devices. Any manufactured products utilized for inlet protection must be constructed of materials equally durable and effective as those provided in this practice. They must be able to be secured such that construction site runoff is intercepted, ponded and filtered prior to entering the storm drain except during extreme flows. Devices must allow the removal of captured material without falling into the catch basin.

Effective storm drain inlet protection collects sediment and therefore must be cleaned regu-larly to prevent clogging and subsequent flooding conditions, piping, or overtopping of the control structures. Sediment barriers that sag, fall over, or are not properly secured, must be promptly repaired or replaced.

Inlet protection shall be inspected weekly and after each rainfall event. Areas where there is active traffic shall be inspected daily. Repairs shall be made as needed to assure the practice is performing as intended. Sediment shall be removed when accumulation is one-half the height of the trap. Sediment shall not be washed into the inlet. Sediment shall be removed and placed in a location where it is stable and not subject to erosion.

Once the contributing drainage area has been properly stabilized, all filter material and collected sediment shall be removed and properly disposed.

Maintenance

38 CHAPTER 6 Sediment Controls for

Excavated Drop Inlet Sediment Protection

1. The excavated trap should be sized to provide a minimum storage capacity calculated at the rate of 135 cubic yards for one (1) acre of drainage area. A trap should be no less than one (1) foot, nor more than two (2) feet deep measured from the top of the inlet structure. Side slopes should not be steeper than 2:1.

2. The slopes of the trap may vary to fit the drainage area and terrain.

3. Where the area receives concentrated flows, such as in a highway median, provide the trap with a shape having a 2:1 ratio of length to width, with the length oriented in the direction of the flow.

4. Sediment should be removed and the trap restored to the original depth when the sediment has accumulated to 40% the design depth of the trap. Removed sediment should be spread in a suitable area and stabilized so it will not erode.

5. During final grading, the inlet should be protected with geotextile-stone inlet protection. Once final grading is achieved, sod or a suitable temporary erosion control material shall be implemented to protect the area until permanent vegetation is established.

CHAPTER 6 Sediment Controls 39

1. Inlet protection shall be constructed either before upslope land disturbance begins or before the inlet becomes functional.

2. The earth around the inlet shall be excavated completely to a depth at least 18 inches.

3. The wooden frame shall be constructed of 2-inch by 4-inch construction grade lumber. The 2-inch by 4-inch posts shall be driven one (1) ft. into the ground at four corners of the inlet and the top portion of 2-inch by 4-inch frame assembled using the overlap joint shown. The top of the frame shall be at least 6 inches below adjacent roads if ponded water will pose a safety hazard to traffic.

4. Wire mesh shall be of sufficient strength to support fabric with water fully impounded against it. It shall be stretched tightly around the frame and fastened securely to the frame.

5. Geotextile material shall have an equivalent opening size of 20-40 sieve and be resistant to sunlight. It shall be stretched tightly around the frame and fastened securely.

It shall extend from the top of the frame to 18 inches below the inlet notch elevation. The geotextile shall over-lap across one side of the inlet so the ends of the cloth are not fastened to the same post.

6. Backfill shall be placed around the inlet in compacted 6-inch layers until the earth is even with notch elevation on ends and top elevation on sides.

7. A compacted earth dike or check dam shall be con-structed in the ditch line below the inlet if the inlet is not in a depression. The top of the dike shall be at least 6 inches higher than the top of the frame.

Specifications for

Geotextile Inlet Protection

Compact backfill around Inlet

40 CHAPTER 6 Sediment Controls for

Geotextile-Stone Inlet Protection

1. Inlet protecion shall be constructed either before upslope land disturbance begins or before the inlet becomes functional.

2. Geotextile and/or wire material shall be placed over the top of the storm sewer and approximately six (6) inches of 2-inch or smaller clean aggregate placed on top. Extra support for geotextile is provided by placing hardware cloth or wire mesh across the inlet cover. The wire should be no larger than ½" mesh and should extend an extra 12 inches across the top and sides of the inlet cover.

3. Maintenance must be performed regularly, especially after storm events. When clogging of the stone or geotextile occurs, the material must be removed and replaced.

CHAPTER 6 Sediment Controls 41 for

Geotextile - Stone Inlet Protection for Curb Inlets

42 CHAPTER 6 Sediment Controls for

Geotextile-Stone Inlet Protection for Curb Inlets

1. Inlet protection shall be constructed either before upslope land disturbance begins or before the inlet becomes functional.

2. Construct a wooden frame of 2-by-4-in. construction-grade lumber. The end spacers shall be a minimum of 1

ft. beyond both ends of the throat opening. The anchors shall be nailed to 2-by-4-in. stakes driven on the opposite side of the curb.

3. The wire mesh shall be of sufficient strength to support fabric and stone. It shall be a continuous piece with a minimum width of 30 in. and 4 ft. longer than the throat length of the inlet, 2 ft. on each side.

4. Geotextile cloth shall have an equivalent opening size (EOS) of 20-40 sieve and be resistant to sunlight. It shall be at least the same size as the wire mesh.

5. The wire mesh and geotextile cloth shall be formed to the concrete gutter and against the face of the curb on both sides of the inlet and securely fastened to the 2-by-4-in.

frame.

6. Two-inch stone shall be placed over the wire mesh and geotextile in such a manner as to prevent water from entering the inlet under or around the geotextile cloth.

7. This type of protection must be inspected frequently and the stone and/or geotextile replaced when clogged with sediment.

CHAPTER 6 Sediment Controls 43 for

Block and Gravel Drop Inlet Filter

1. Place 4-inch by 8-inch by 12-inch concrete blocks lengthwise on their sides in a single row around the perimeter of the inlet, with the ends of adjacent blocks abutting. The height of the barrier can be varied, depend-ing upon the design needs, by stacking combinations of the same size blocks. The barrier of blocks should be at least 12-inches high but no greater than 24-inches high.

2. Wire mesh should be placed over the outside vertical face (webbing) of the concrete blocks to prevent stone from being washed through the block cores. Hardware cloth or comparable wire mesh with ½-inch openings should be used.

3. Two-inch stone should be piled against the wire to the top of the block barrier, as shown below.

4. If the stone filter becomes clogged with sediment so that it no longer adequately performs its function, pull stone away from the blocks, clean and/or replace.

44 CHAPTER 6 Sediment Controls

Filter berms are sediment trapping practices that utilize a compost/mulch material. They are typically installed with pneumatic equipment. Filter berms reduce sediment from runoff by slowing and filtering runoff, and dissipating flow.

Filter berms are appropriate on nearly level ground or slopes up to 5:1, where runoff occurs as sheet flow. Filter berms cannot effectively treat flows in gullies, ditches or channels.

For more severe…