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 CAN USE SYMBOLS KEYED TO LEGEND Limit length of open trench at days end Written E&S plan if > 5,000 SF disturbed, should be reviewed by CD
FLOW Pipe flume crossing LARGE ENOUGH TO HANDLE EXPECTED FLOWS DURING CONSTRUCTION PUMPED WATER FILTER BAG
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 NOT 8 SPECS FOR COMPOST FILTER MEDIA
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
Not Adequately Compacted FAIL
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
Questions? CONTACT INFO: PEG NOVELLO, CPESC GIBSON-THOMAS ENGINEERING CO., INC. 724-539-8562 PEGZ@GIBSON-THOMAS.COM