Utility and Sanitary Sewer Permitting & Design

Gibson-Thomas Engineering Co., Inc.

Consulting Engineers

Utility Line Design

• Provide service to communities in need with minimal piping needed – minimize $$

• Try to stay within existing right-of-ways

–Sometimes difficult to get r/w signed

• Avoid sharp angles between sections

• Minimize stream & wetland impacts

• Cross at right angle to stream where possible

Sewer and Water Line Design

• Sanitary sewers follow topography to use gravity flow, avoid installing pump stations

• Waterlines are pressurized, can flow uphill and can usually stay along roads - make loops if possible in distribution lines

• MHs at bends or < 400’, fire hydrants < 1200’

• No MHs in streams, no PSs in floodway

NPDES Permitting

• NPDES required if > 1 acre disturbed

• Multiply length pipeline X 10’ (for WL) to 20’ (for SS) = disturbed area

• Buffer requirement may be waived on linear projects, alternatives analysis

• No PCSM or rudimentary PCSM Plan if no impervious – DEP requires for individual permit

• Keep track of expiration date

Other Permits

• General Permits (usually GP-5, maybe GP-4 and/or GP-8) - WCD can issue

–E&S needs reviewed no matter amount of disturbance

• HOPs for all state roads, some co. and twp.

• RR crossings

• SLLA on larger waters – reviewing agency will inform you if needed

Waste Sites

• Arrange waste areas ahead of time

• Mostly needed for in-road part of projects

• Many people want fill –many sites unsuitable

• Wetlands are not suitable waste sites

• No fill within 50 ft. of stream

• Need E&S plan, CD review if > 5000 SF

• Need NPDES permit if > 1 acre

E&S Control Plans for Utility Lines

• Show locations of controls on plans – Sediment filter fence/socks

– RCEs where going off road

– Water bars on slopes

– Sediment filter bags

– Stormwater inlets

• Provide construction details

• Limit length of open trench at days end

• Written E&S plan if > 5,000 SF disturbed, should be reviewed by CD

CAN USE SYMBOLS KEYED TO LEGEND

Pipe flume crossing LARGE ENOUGH TO HANDLE EXPECTED FLOWS DURING CONSTRUCTION

PUMPED WATER FILTER BAG

FLO

W

Pump Bypass

PUMPED WATER FILTER BAG

Temporary Cofferdam

Water Bars

Required Spacing for Permanent

Waterbars

Percent Slope Spacing (FT)

< 5 *

5 - 15 150

15 - 30 100

> 30 50

* Permanent waterbars are required at all stream, river, and other water-body crossings as well as upslope from roadway and railroad cut slopes. Otherwise not required.

Trench Plugs

Required Spacing and Materials for Trench Plugs

Trench Slope

(%)

Spacing (FT) Plug Material

< 5 * *

5 - 15 500 ** Earth Filled

Sacks

15 - 25 300 ** Earth Filled

Sacks

25 - 35 200 ** Earth Filled

Sacks

35 - 100 100 ** Earth Filled

Sacks

> 100 50 Cement Filled

Bags (Wetted) or

Mortared Stone

* Trench Plugs are required at all stream, river, or water-body crossings regardless of trench slope. Otherwise not required. ** Topsoil may not be used to fill sacks.

Inlet protection INLET FILTER BAG STONE AND CONCRETE BLOCK

Filter Fabric Fence • Usually use 18” or 30” fence if

within 50’ of water or wetland

• Place close to trench to prevent sediments from migrating from work area and stay w/in R/W

• Must be toed in properly to work

• Must be inspected and maintained

Compost Filter Socks

• Compost-filled silt socks for HQ or EV

–Considered ABACT BMP

• More effective than silt fence - higher flow rates, better trapping efficieny

• Less impact when installed or removed

• May be left in place, cut and spread on site or biodegradable

Compost Filter Sock Detail 12” SOCK = 18” SF 18” SOCK = 30” SF

SPECS FOR COMPOST

FILTER MEDIA

NOT 8”

Pumped Water Filter Bag

OR CAN BE PLACED ON BED OF 2A OR #57 STONE

Pipe bedding and backfill

• Stone or rock dust bedding around pipe

• Select backfill with no large stones – no frozen, muddy, organic, ashes, slag, etc.

• If within 3’ of pavement on state road, 100% stone backfill per PADOT

• Fill in layers or lifts to within 4” to allow room for topsoil/pavement

Pipe bedding and backfill (cont.)

• Mechanically tamp in lifts to compact backfill and avoid soft spots

• Do NOT use backhoe bucket to tamp

• Restoration - repave/revegetate ASAP

• Cold patch for temporary repaving in cold weather

• Reserve topsoil and spread 4” thick, lime and fertilizer, seed & mulch

Mechanical Tampers

FAIL

Not Adequately Compacted

RESTORED PAVEMENT

General Permits for Utility Lines

• GP-5 for Utility Line Crossings* for wetlands and streams if drainage area > 100 acres

• GP-8 for Temporary Equipment Crossings

• GP-4 for Outfall Structures for effluent from plants

• Can use 1 form for multiple crossings/outfalls

* If EV streams and/or associated wetlands, must have Joint Permit, issued by DEP

GP-5 Conditions

• Maximum size utility line allowed is 36 inches in diameter

• Under streambeds, must have a minimum of three (3) feet of cover

• Trenches excavated shall be the minimum width necessary

• Prevent sediments from entering the stream

• Lay pipe so as to eliminate the formation of a permanent ridge in the streambed

GP-5 Conditions (cont.)

• Protect existing vegetation and features

• Investigate for drinking water intakes or reservoirs for public and private water supplies within five (5) miles downstream

• Mats, pads, or other similar devices shall be used where equipment will cross wetlands . Mounding of fill material to allow for settlement in the trench is permitted in wetland crossings

• Minimize erosion and prevent sediments from going into any wetland

GP-5 Conditions (cont.)

• Archaeological artifacts that are discovered must be protected and their discovery promptly reported to PHMC

• Utility line crossings of streams should at a right angle to the stream where possible

• If possible, crossings made “in the dry”by using a pipe flume or pump bypass

• Need permit from the Fish & Boat Comm. To use explosives in streams

Stream/Wetland Impacts

• Minimize amount of disturbance

• Minimze length of time of impact – Minor stream crossings completed w/in 24

hrs

– Major stream crossings completed w/in 48 hrs

• Contact PA F&B 10 days prior

• No in-stream work in TSF March 1 – June 15

Stream/Wetland Impacts (cont.)

• Segregate and replace hydric soils in wetlands

• Place riprap along disturbed stream banks R-6 minimum, R-7 on large stream

• Place trench plugs on either side of stream or wetland

• Use matting at swale crossings

Types of Utility Crossings for GP-5

• Open cut trench – must divert stream flow around work area, either flumed, pumped, or cofferdam

• Boring under streams or wetlands

• Under or over an existing culvert if > 100 ac.

• Along existing bridge

Open-cut Stream Crossing Sketch

SHOW STREAM FLOW, CONTROLS, LIMIT OF DISTURBANCE

Stream Crossing Cross-section

CONCRETE ENCASEMENT

Boring Under Stream/Wetland

SHOW DIRECTION OF FLOW, LIMIT OF DISTURBANCE, CONTROLS

Bored Cross-section

SHOW DIMENSIONS, PITS, SILT BARRIERS, SEDIMENT BAG

This can be so boring!

Pipe/Culvert Crossing Sketch Plan

LIMIT OF

DISTURBANCE

SHOW DIRECTION OF FLOW, CONTROLS, LIMIT OF DISTURBANCE

Pipe/culvert Crossing Section View

Crossing Under Existing Pipe

Wetland Crossing Sketch Plan

SHOW DIRECTION OF FLOW, LIMIT OF DISTURBANCE AND CONTROLS

NOTE RIPRAP ALONG BENDS IN STREAM

Wetland Crossing Cross-section

GENERAL NOTES: 1. Trench width and disturbance shall be kept to minimum. 2. Protect and preserve vegetation to the maximum extent possible. 3. Mats, pads or similar devices shall be used where equipment cannot avoid crossing wetlands. 4. Restore original grades through wetlands after trenching and backfilling. 5. Mounding of fill material to allow for settlement in trench is permitted. 6. Minimize erosion and preclude its entering wetland areas.

WOOD BRIDGE, SWAMP MAT, GEOTEXTILE W/ EXPANDED METAL, PVC, TIRE MATS, WIDE TIRES

GP-4 Outfall Structure Sketch Plan

SHOW STREAM FLOW, OUTLET STRUCTURE, APRON DIMENSIONS, LIMIT OF STREAM DISTURBANCE

GP-4 Outfall Structure Cross-section

GP Registrations & Attachments

• Original signed GP Registration form (Rev. 6/2011)

• Sketch plan and cross-section for each crossing

• USGS with crossing numbers/locations shown

• PNDI results and responses/clearances

–www.naturalheritage.state.pa.us

More Attachments to GP

• Act 14 notices and proof of receipt (certified mail reciept)

• Color photographs

• Cumulative Impacts Screening Form – signed by applicant (Rev. 7/2011)

• E&S Plan (send to CD if DEP will review the GP)

ACOE 45 Day Review

• > 250 ft. stream impact

• Permanent loss of > 1 acre waters of the U.S. including wetlands

• Need PHMC clearance

• Provide table with Lat & Long, name of water, linear feet and acreage of impact, Ch. 93 designation, and description of impact

CONTACT INFO:

PEG NOVELLO, CPESC

GIBSON-THOMAS ENGINEERING CO., INC.

724-539-8562

PEGZ@GIBSON-THOMAS.COM

Questions?