Attachment A Special Provisions and Specifications~7.pdf

SPECIAL PROVISIONS AND SPECIFICATIONS FOR

US101: MP315.89, MP332.55, & MP344.44 HORIZONTAL DRAINS

SCOPE

The work to be completed under this contract consists of the following, located on the Oregon Coast Highway, (US101), at the following locations: MP315.89, MP332.55 and MP 344.44, in Curry County, OR, which consists of supplying the materials, equipment, labor and incidentals required to perform the following tasks as described in the Contract plans and specifications:

1. Provide Temporary Work Zone Traffic Control at all site locations.

2. Provide and Maintain Erosion Control at all site locations.

3. Construct Temporary Access Roads and Drill Pads for the construction of Horizontal

Drains.

4. Furnish and Install 13,240 feet of Horizontal Drains.

5. Furnish and Install 1,986 feet of 12-inch HDPE Drainpipe.

6. Furnish and Install 407 feet of 24-inch HDPE Drainpipe.

7. Furnish and Install 120 12-inch Pipe Slope Anchors and 25 24-inch Pipe Slope

Anchors.

8. Furnish and Install 33 8-inch Storm Sewer Pipe Assemblies.

9. Furnish and Install 4 12-inch x 24-inch Pipe Wyes.

10. Perform additional and incidental work as detailed in the Contract plans and specifications and as directed.

PROJECT INFORMATION

General information pertaining to this Project may be obtained from the following:

Jessica Spann, Project Manager 307 Highway 42 Coquille, OR 97423 Phone (541) 315-5999 Email: Jessica.Spann@ODOT.Oregon.gov

APPLICABLE STANDARD SPECIFICATIONS & SPECIAL PROVISIONS

2024 OREGON STANDARD SPECIFICATIONS FOR CONSTRUCTION: The 2024 Oregon Standard Specifications for Construction (“Standard Specifications”) include detailed technical specifications that apply to this Invitation to Bid (ITB) and resulting Contract.

Some sections of the technical specifications are identified and modified below. Sections of the technical specifications not identified below remain applicable to the Contract according to their original terms. Part 00100 of the Standard Specifications (General Conditions) is not applicable to the Contract; however, if a technical specification (Parts 200 and beyond) references a section from Part 00100, that section from Part 00100 applies to the Contract for purposes of supporting and giving full effect to the technical specification. The Standard Specifications are available online:

ATTACHMENT A

http://www.oregon.gov/ODOT/Business/Pages/Standard_Specifications.aspx

Silence of Specifications: The apparent silence of the specifications as to any detail, or the apparent omission of a detailed description concerning any point, shall be regarded as meaning that the highest value commercial practices are to prevail and that only materials and workmanship of first quality are to be used.

Where neither the Special Provisions nor the bid schedule indicate separate payment for the work to be completed under this Contract, perform the work as incidental for which no separate measurement or payment will be made.

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SECTION 00210 - MOBILIZATION

Comply with Section 00210 of the Standard Specifications.

SECTION 00221 - COMMON PROVISIONS FOR WORK ZONE TRAFFIC CONTROL

Comply with Section 00221 of the Standard Specifications modified as follows:

00221.06 Traffic Control Plan - Replace this subsection with the following subsection:

00221.06 Traffic Control Plan and Tourist-Oriented Directional and Business Logo Signs –

(a) Traffic Control Plan - Submit one of the following, 5 Calendar Days before the preconstruction conference:

(1) Agency Traffic Control Plan - If the Contractor intends to use the Agency TCP without modification, a written notification indicating that the Agency TCP will be used without modification.

(2) Contractor-Modified Traffic Control Plan - The Contractor may request to use a Contractor-modified Agency TCP, or a TCP developed by the Contractor. Do not use a modified TCP, or a TCP developed by the Contractor, unless approved by the Engineer. Use the Agency TCP unless a modified TCP, or a TCP developed by the Contractor is accepted.

The Engineer is not obligated to consider any modified Agency TCP or a TCP developed by the Contractor. The Agency will not be liable to the Contractor for failure to accept or act upon any request for a modified Agency TCP or a TCP developed by the Contractor.

To conserve time and funds, the Contractor may first submit a written request for a preliminary review by the Engineer. The request should contain a description of the proposal together with a rough estimate of anticipated dollar and time impacts. The Engineer will, within a reasonable time, respond to the Contractor in writing whether or not the request would be considered by the Agency.

If requesting a Contractor-modified Agency TCP, or a TCP developed by the Contractor, at a minimum the request shall meet all requirements of the Contract documents and comply with the Project transportation management plan (TMP).

Provide the following information:

• Stamped Working Drawings according to 00150.35 that include the proposed TCP showing all TCM and quantities of TCD.

• A TPAR plan that includes:

• Details and features used to provide pedestrian accessibility.

• Pedestrian staging Plans at a scale no smaller than 1 inch = 50 feet.

• Temporary alternate facilities or detour routes for pedestrian traffic.

• Staging sequences and details for Work affecting vehicular, pedestrian, and bicycle traffic.

• Proposed order and duration of the TCM.

• A detailed temporary striping plan.

If the Contractor’s request to use a Contractor-modified Agency TCP, or a TCP developed by the Contractor is approved in whole or in part, acceptance will be made by a Change Order.

The Engineer will establish prices that represent a fair measure of the value of Work to be added, changed, or deleted as a result of any accepted modifications to the Agency TCP or an accepted TCP developed by the Contractor.

Once a TCP has been accepted by the Engineer, any additional modifications must be submitted by the Contractor for Agency review following the procedure described above. The Engineer is not obligated to consider additional modifications to a previously approved TCP.

(b) Tourist-Oriented Directional and Business Logo Signs - Submit one of the following for approval, at least 5 Calendar Days before the preconstruction conference:

(1) No Signs - If there are no tourist-oriented directional (TOD) or business logo signs on the Project, a written notification that no TOD or business logo signs exist within the Project limits or

(2) Signs - Submit one copy of a sketch map of the Project showing all existing TOD and business logo signs and a written narrative describing how these signs will be kept in service and protected throughout all the construction stages. If modifications are necessary, submit updated information to the Engineer for approval at least 21 Calendar Days before the change is needed.

00221.60 Temporary Traffic Control Devices – Replace the paragraph that begins “TCD delivered to the Project Site found…” with the following paragraph:

Repair or replace TCD delivered to the Project Site found to be in “marginal” or “unacceptable” condition, at no additional cost to the Agency.

00221.90(b) Temporary Protection and Direction of Traffic – Replace the bullet that begins “Providing, Surfacing, maintain…” with the following bullet:

• Providing, surfacing, maintaining, removing, and restoring the TPAR.

SECTION 00222 – TEMPORARY TRAFFIC CONTROL SIGNS

Comply with Section 00222 of the Standard Specifications.

SECTION 00224 - TEMPORARY TRAFFIC CHANNELIZING DEVICES

Comply with Section 00224 of the Standard Specifications.

SECTION 00231 - TEMPORARY ACCESS ROAD

Section 00231, which is not a Standard Specification, is included in this Project by Special Provision.

Description

00231.00 Scope - This Work consists of constructing, maintaining, and removing temporary, unpaved access roads for the use of Contractor and Agency Equipment and personnel as needed, shown, or directed.

Materials

00231.11 Geotextile - Furnish subgrade geotextile, embankment geotextile, or riprap geotextile, at the Contractor’s option. Geotextile shall meet the requirements of Section 02320, with documentation according to 02320.10(c).

00231.12 Geogrid - Subgrade reinforcement geogrid, if used, shall meet the requirements of Section 02320.

00231.13 Road Material - Furnish crushed Aggregate Base, stone embankment, or other suitable Granular Material capable of supporting the weight of Equipment intended to use the temporary access road.

Construction

00231.41 Clearing - Clearing brush and vegetation for temporary access roads is allowed in the areas shown or where directed. Preserve and protect trees as shown or directed.

00231.42 Temporary Access Road - Construct temporary access roads to the width, grade, profile, and depth of base sufficient to support the weight of Equipment using the road.

Install geotextile or geogrid prior to placement of road material.

00231.43 Not for Public Traffic - Do not direct or allow Public Traffic to use temporary access roads constructed according to this Section.

00231.44 Verification of Original Ground - Test the density of the original ground according to TM 158, in the presence of the Engineer, before beginning construction of the temporary access road and after removing it. If post-removal density testing indicates that the original ground has been weakened by construction activities, or the presence or use of the temporary access road, correct the deficient condition in an approved manner and at no additional expense to the Agency.

00231.45 Temporary Drill Pad - Construct temporary drill pads to the width, grade, profile, and depth of base sufficient to support the weight of Equipment using the pads for installation of horizontal drains. Install geotextile or geogrid prior to placement of road material.

Maintenance

00231.60 Surface Maintenance - Maintain temporary access roads so that the road surfaces remain firm, smooth, free of ruts or standing water, and are graded to prevent concentrations of runoff water. Promptly remove accumulations of mud or debris.

Finishing and Cleaning Up

00231.70 General - When a temporary access road is no longer needed, do the following:

• Remove all Materials.

• Restore areas occupied by the temporary access road to the original ground contours or as directed.

• Apply permanent mulching and seeding to the area occupied by the temporary access road according to Section 01030.

• Dispose of excess materials according to 00330.41(a)(5).

Measurement

00231.80 Measurement - Except for permanent mulching and seeding, no measurement of quantities will be made for Work performed under this Section.

Permanent mulching and seeding will be measured according to 01030.80.

Payment

00231.90 Payment - The accepted quantities of Work performed under this Section, except for permanent seeding work, will be paid for at the Contract Lump Sum amount for the item "Construct and Remove Temporary Access Road".

Payment will be payment in full for furnishing and placing all Materials, and for furnishing all Equipment, labor, and Incidentals necessary to complete the Work as specified.

No separate or additional payment will be made for removing and disposing of temporary access road materials or for restoring the areas to original ground contours.

Permanent seeding Work will be paid for according to 01030.90.

SECTION 00280 - EROSION AND SEDIMENT CONTROL

Comply with Section 00280 of the Standard Specifications.

SECTION 00290 - ENVIRONMENTAL PROTECTION

Comply with Section 00290 of the Standard Specifications modified as follows:

Add the following subsection:

00290.30(a)(7) Water Quality:

• Do not discharge water contaminated by pollutants including sediment, drilling fluids and waste, concrete, grout, or water contained within a work area isolation, into any waters of the State or U.S. or conveyances draining thereto until it has been treated using Materials such as those listed in 00280.15 or 00280.16 or by pumping to a vegetated upland location. Do not allow Project discharges to increase the concentration of any pollutant in the receiving water to a level that exceeds the limits prescribed by OAR 340-041.

• Implement containment measures adequate to prevent pollutants from entering waters of the State or U.S. Such pollutants include but are not limited to construction and demolition materials, waste spoils, fuel or petroleum products, detergents, silt, welding slag and grindings, concrete sawcutting by-products and sandblasting abrasives.

• Do not allow curing concrete or grout to be submerged within waters of the State or U.S. less than 24 hours after placement, except within work area isolation

• If Work in or around waters of the State or U.S. violate permit conditions or any requirement of this subsection, stop such Work and notify the Engineer.

00290.34 Protection of Fish and Fish Habitat - Add the following paragraph:

Meet with the Agency Environmental Representative, Engineer, and inspector on site, before moving equipment on-site or beginning any work, to ensure that all parties understand the locations of sensitive biological sites and the measures that are required to be taken to protect them.

00290.34(a) Regulated Work Areas - Add the following to the end of this subsection:

Add the following subsection:

00290.34(c) Aquatic Species Protection Measures Required by Environmental Permits:

(1) General Requirements:

Use heavy equipment as follows:

• Secure absorbent material around all stationary power equipment (for example:

generators, cranes, drilling equipment) operated within 150 feet of wetlands, waters of the State, waters of the U. S., drainage ditches, or water quality facilities to prevent leaks, unless suitable containment is provided to prevent spills from entering waters of the State or waters of the U.S.

• Store fuel and maintain all equipment in staging areas that are at least 150 feet away from any waters of the State, waters of the U.S., or storm inlet or on an impervious surface that is isolated from any waters of the State, waters of the U.S., or storm inlet.

(3) Water Intake Screening - Install, operate, and maintain fish screens on each water intake used for project construction, including pumps used to isolate an in-water work area. When drawing or pumping water from any stream, protect fish by equipping intakes with screens having a minimum 27 percent open area and meeting the following requirements:

• Perforated plate openings shall be 3/32 inch or smaller.

• Mesh or woven wire screen openings shall be 3/32 inch or smaller in the narrowest direction.

• Profile bar screen or wedge wire openings shall be 1/16 inch or smaller in the narrow direction.

Choose size and position of screens to meet the following criteria in Table 00290-1:

Table 00290-1

Type Approach Velocity 1 (Ft./Sec.)

Sweeping Velocity 2 (Ft./Sec.)

Wetted Area of Screen (Sq. Ft.)

Comments

Ditch Screen ≤ 0.4 Shall exceed approach velocity

Divide max. water flow rate (cfs) by

0.4 fps

If screen is longer than 4 feet, angle 45° or less to stream flow

Screen with proven self-cleaning system ≤ 0.4 –

Divide max. water flow rate (cfs) by

0.4 fps

Screen with no cleaning system other than manual

≤ 0.2 – Divide max. water flow rate (cfs) by

0.2 fps

Pump rate 1 cfs or less

1 Velocity perpendicular to screen face at a distance of approximately 3 inches 2 Velocity parallel to screen

Provide ditch screens with a bypass system to transport fish safely and rapidly back to the stream.

(5) Site Restoration - Restore damaged streambanks to a natural slope, pattern, and profile suitable for establishment of permanent woody vegetation unless precluded by pre-project conditions (for example: natural rock substrate):

• Stabilize all disturbed soils, including obliteration of temporary access roads, following any break in work unless construction will resume in 4 Calendar Days.

00290.36(a) Migratory Birds - Add the following to the end of this subsection:

For any trees that need to be removed prior to September 1, 2025, an ODOT Environmental Representative will review each tree to check for nesting birds. Notify the Engineer, in writing, a minimum of 10 Calendar Days prior to starting activities that would remove trees.

00290.41 Protection of Waters of the U.S. or State - Add the following to the end of this subsection:

There are two flagged Wetlands (including one that is near one of the proposed drill pad locations at the US101: M.P. 332.55 location. These wetlands are flagged, and will be covered during the Environmental walk-thru discussed in Section 290.34. Please avoid any impacts to those wetlands.

00290.51 Protection of Sensitive Cultural Sites - Add the following to the end of this subsection:

There are sensitive cultural sites or areas of high probability for cultural resources on this Project. At the time of preparation of the Plans, __one_ site was identified.

The Region Environmental Coordinator for this Project is __Sam Dunnavant__________.

The Agency Archaeology Representative for this Project is __Jessie Plueard___.

All contact with the Agency Archaeology Representative and the Region Environmental Coordinator shall be through the Engineer.

An Inadvertent Discovery Plan (IDP) has been developed for this project. The IDP is available from the Engineer.

Meet with the Engineer at least 10 Calendar Days prior to beginning ground disturbing activities to discuss sensitive cultural sites on the Project. Required attendees include:

• The Contractor’s supervisory personnel.

• Subcontractors, including contract archaeological monitors, and supervisory personnel who will be involved in ground disturbing activities.

• Agency archaeology representative or region environmental coordinator.

• When applicable, tribal representative(s) or monitor(s).

Prior to beginning On-Site Work, install work zone fencing from section 00221.13 of the QPL, or lath and flagging, around no work zones, as shown or as directed.

An Archaeological Monitor is required to be on-site during all ground-disturbing activities at the M.P. 332.55 location, unless otherwise notified. Notify the Engineer 10 Calendar Days before beginning ground-disturbing activities.

SECTION 00305 - CONSTRUCTION SURVEY WORK

Comply with Section 00305 of the Standard Specifications.

SECTION 00310 - REMOVAL OF STRUCTURES AND OBSTRUCTIONS

Comply with Section 00310 of the Standard Specifications.

SECTION 00320 – CLEARING AND GRUBBING

Comply with Section 00320 of the Standard Specifications and modified as follows:

00320.80 Measurement - No separate measurement will be made for clearing and grubbing.

00320.90 Payment - No separate or additional payment will be made. This work is considered incidental to performing the work under section 00231.

SECTION 00330 - EARTHWORK

Comply with Section 00330 of the Standard Specifications modified as follows:

00330.00 Scope - Add the following paragraph to the end of this subsection:

Clear and grub the proposed access roads and drill pads as required for installation of horizontal drains, and as directed by the Engineer. This work includes the removal of asphalt within the limits shown, failed slope debris, fallen and standing trees, and existing in-place native material within the excavations as directed by the Engineer. All matter and debris accumulated from removal of structures and obstructions, and clearing and grubbing operation become the property of the Contractor at the place of origin, to be disposed of at the Contactor’s expense.

00330.80 Measurement – Replace this subsection with the following paragraphs:

No separate measurement will be made for general excavation. Work under removal of structures and obstructions and clearing and grubbing are incidental to temporary access road construction and will have no separate measurement.

00330.81 Excavation Basis Measurement – Remove this subsection.

SECTION 00431 - HORIZONTAL DRAINS AND DISCHARGE SYSTEMS

Section 00431, which is not in the Standard Specifications, is included in this project by Special Provision.

Description

00431.00 Scope - This work consists of furnishing and installing horizontal drains as shown.

The work also includes constructing and maintaining erosion and sediment control for the horizontal drain drilling. Perform jetting of horizontal drains after all drains have been installed.

00431.01 General - Submit a drilling and installation plan to the Agency 5 calendar days prior to beginning any work or within 10 days of receiving a notice to proceed. Details to be included in the plan are as follows:

• The method, equipment and materials proposed for drilling and installing the permanent steel casing and horizontal drains.

• Methods of protecting existing slope surface during horizontal drilling activity.

• Methods to conform specific erosion and sediment control structures for horizontal drains to the overall erosion and sediment control for the project.

• Methods for controlling drill fluids, and drain discharge water, compatible with the erosion and sediment control plan.

• Methods for obtaining drilling water.

• Methods for controlling fuels and lubricants.

At least 5 calendar days prior to beginning drilling work, the drilling foreman and lead driller shall meet with the Agency to review the drilling and installation plan. Do not commence drilling until an erosion and sediment control plan according to Section 00280 has been approved in writing by the Agency and all erosion and sediment control measures are in place.

The Engineer may revise drain lengths, orientations, and inclinations as the work progresses.

00431.05 Subsurface Conditions –Expected ground conditions within which horizontal drains are to be drilled and installed consists of intermixed landslide debris containing various percentages of clay, silt, sand, and gravel to boulder sized rock fragments, which range from siltstone to serpentinite. Groundwater is anticipated to be found in the horizontal drain drill holes. Temporary casing, that could include the drill rod, will be required for installing the 1.5 inch PVC drain pipe.

Materials

00431.10 Horizontal Drain Pipe - Construct horizontal drains of nominal 1.5 inch, Schedule 80 polyvinyl chloride (PVC) plastic pipe conforming to the requirements of ASTM D 1784 and D 1785. The type, grade, and design stress designation of the pipe shall be either 1120, 1220, 2110, 2112, 2116 or 2120 as specified in ASTM D 1785.

Slotted pipe shall have three rows of slots. The rows shall be in the longitudinal direction of the pipe and the slots shall be cut in the circumferential direction of the pipe. The rows shall be centered on 3 of the quarter points (90 degrees apart) of the pipe circumference. Each row of slots shall conform to the following configuration.

Number of Slots per Foot Per Row (Approximate)

Width of Slot

Minimum Opening per Foot

22 0.02 inch 1 inch2

Space slots uniformly along the pipe. The minimum opening is measured on the inner surface of the pipe.

Fittings and valves for the PVC plastic pipe shall be Schedule 80, Type II, PVC, solvent weld type fittings conforming to the requirements in ASTM Designation D 2467. Machined male and female ends may be used in lieu of couplings.

Provide unslotted PVC plastic pipe at the outlet end of each drain and for drain pipe extensions. At outlet ends where the pipe will be permanently exposed furnish PVC pipe and fittings that are treated for UV protection.

00431.11 Steel Casing - Provide steel casing meeting the requirements of ASTM A 53 with an inside diameter of 5 inches nominal and a thickness of Schedule 40 at the discharge end of each drain. Added lengths of casing shall be welded around the entire perimeter of the casing.

00431.12 Drilling Water and Slurries - Furnish water for the drilling operations. Drill water and clean water from horizontal drains shall be re-circulated to the extent practical for drilling operations. The use of drilling slurries is not permitted.

00431.13 Compression Seals - Furnish commercial watertight compression fittings to seal the annular space between the horizontal drain pipe and the steel casing.

00431.14 Outlet Hose - Furnish polyethylene pipe of Class 80, SDR 15, medium density, meeting the requirements ASTM D 2239, conforming to U.S. Commercial Standard CS-255, and approved by the National Sanitation Foundation (NSF). Furnish required clamps, solvent cement, and connections to provide continuous water tight outlet pipe for routing clean water from horizontal drain pipes to outlet locations as detailed on the project plans.

Equipment

00431.20 Drilling Equipment - Furnish equipment for drilling and drain pipe installation operations.

The drilling equipment shall have:

• Adequate power to penetrate the anticipated soil and rock materials to the lengths indicated on the plans and specifications.

• Capability to install 5-inch diameter steel casing up to 200 feet long.

• Capability to drill 4- to 6-inch diameter holes up to 500 feet long at inclinations of minus

5 to plus 10 degrees from horizontal alignment in varied subsurface materials and conditions at the project site.

• Casing or hollow drill rods that perform as casing to permit the installation of permanent drain pipe (1.5-inch diameter) the full length of the drilled hole.

• Adequate power, torque, and feed pressure to penetrate anticipated materials to the length and length indicated on the plans and in these special provisions.

00431.21 Jetting Equipment - Furnish equipment for jetting operations. The jetting equipment shall have:

• Pumps capable of generating water pressures up to at least 5,000 psi and a flow rate up to at least 18 gpm.

• Fitted with a minimum of 900 feet of hose, marked in 10 foot increments with a working pressure up to at least 5,000 psi.

• Capable of being inserted into 1.5 inch horizontal drain pipes.

Provide jet nozzles with a minimum of six equally spaced holes made on 15-degree angles with the axis of the base (for side-flushing), some with and some without a single hole front jet at the tip of the head or approved equal.

00431.22 Drain Orientation and Elevation Measuring Equipment - Furnish equipment for determining horizontal drain orientation and elevation. Drain orientation measuring equipment shall have the ability to determine length, inclination, and azimuth for any specified length along the installed horizontal drain. Use a single shot magnetic device or other means approved by the Engineer.

Labor

00431.30 Horizontal Drain Installer Qualifications - Perform the horizontal drain construction using a company and personnel experienced in horizontal drain construction work. Submit a list to the Agency for approval identifying the drilling operators and on-site supervisors assigned to the Project and the company’s experience relevant to the Project.

Experience shall be relevant to the anticipated subsurface materials, groundwater conditions, horizontal drain lengths, and any special construction techniques required. Before the preconstruction conference provide the following information to verify the firm’s experience and the qualifications of personnel scheduled to perform the horizontal drain construction.

• Submit a project reference list of at least five horizontal drain projects successfully completed by the horizontal drain installer in the last five years, with horizontal drain lengths of at least 500 feet, at inclinations from minus 5 to plus 10 degrees from horizontal and in subsurface conditions similar to those described in 00431.05.

Include descriptions of the five projects including: (1) name of client contact, address and telephone number; (2) location of project; (3) contract value; (4) scheduled and actual completion dates; (5) horizontal drain lengths; and (6) type(s) of terrain.

Demonstrate the horizontal drain installer has operated two or more horizontal drain drill rigs concurrently on a project, including the use of additional crews to perform multiple shifts.

• On-site supervisors shall have at least two years’ experience in supervising construction of horizontal drains of similar lengths and scope to those shown in the Plans and in similar subsurface conditions. Experience shall include the direct supervisory responsibility for the on-site construction operations.

• Drill operators shall have at least one year experience in the construction of horizontal drains.

Do not begin work on any horizontal drains until the qualifications have been approved in writing by the Agency. The Agency may suspend the horizontal drain construction if the horizontal drain installer substitutes unapproved personnel during construction. Submit requests for substitution of either on-site supervisors or drill operators to the Agency, who will have seven calendar days to respond to each request.

Construction

00431.40 Horizontal Drain Access – Access to the horizontal drains to be constructed by the contractor according to 00231.

00431.41 Installing Permanent Steel Casing - Install a 5-inch diameter steel casing pipe at horizontal drain locations prior to drilling the drain hole. Locations, inclinations and orientations will be established by the Agency. The steel casing pipe is to be installed into the drill hole and penetrated into the slope face as shown. The Agency may require the installation of longer steel casing.

00431.42 Installing Horizontal Drains - Install drains as shown on the plans. Plan locations are approximate. Final location, length, inclination and sequence of placing horizontal drains will be established by the Agency.

(a) Horizontal Drain Drilling - Protect existing slope surface during horizontal drilling activity.

Pressures must be regulated to avoid blow-outs in the surrounding slope. The Agency may require modifications to drill pressure and rate of advance to control hole alignment.

Drill with casing or hollow drill rods to allow the insertion of 1.5 inch PVC drain pipe to full length of hole prior to removal of casing or hollow drill rods. Horizontal drain pipe shall be oriented so the center slots are in the top half of the pipe. If drill rods are used as casing, knock off drill bit at full length of hole to allow insertion of PVC drain pipe to full length prior to retraction of drill rods. Drill bits shall have one-way check valves to prevent drill water or groundwater from re-entering the drill rod while water head measurements are made.

Remove temporary casing or drill rods with provisions to ensure PVC drain pipe is not damaged or pulled out any distance.

(b) Drill Water Management – Protect existing slope surface during horizontal drilling activity. Re-circulate water to the extent possible to reduce the volume of discharge that needs to be contained and to prevent environmental impacts. Water used for drilling and water developed during drilling operations shall be completely contained by the Contractor.

Drill cuttings shall be removed from the drill site and disposed of regularly according to

00290.20 to avoid environmental impacts. Add flocculant and/or use sand filters, if necessary, to remove sediment.

(c) Elevation Measurement – Furnish all labor, materials, tools, equipment and incidentals necessary for determining elevations on completed drains. During drilling operations, determine drill tip elevation within drilled hole at 100 foot intervals for at least two drains per drill pad as directed by the Engineer. Determine elevation at the end of the length of the remaining horizontal drains.

Demonstrate the accuracy of the elevation measurements to the satisfaction of the Engineer.

(d) Drain Orientation Measurement – Perform horizontal drain orientation readings on at least two drains per drill pad as directed by the Engineer. Provide drain number, length, inclination, and azimuth for each reading submitted for payment. Determine the inclination, and azimuth at 200 feet intervals along horizontal drains selected by the Engineer. Determine length, inclination, and azimuth at the end of the length of each remaining horizontal drains.

(e) Drain Installation - Block and solvent weld the inserted entrance end of the plastic pipe with a rounded or pointed plug that does not extend more than 1 foot beyond the end of the pipe. Provide for inspection by the Engineer.

Install plastic pipe in drilled hole by solvent-welding or threading the PVC pipe together where necessary to form a continuous tube. Construct solvent-welded connections according to manufacturer’s recommendations. Clean each end of the joint, apply solvent to both ends and construct each connection by inserting the pipe squarely to the full distance into the connection socket. Check each joint to confirm completeness and strength of weld. Do not telescope or damage the PVC pipe to the extent that its drainage efficiency will be impaired when completed. The outside portion of each drain shall consist of unslotted pipe, consistent with the Plans. The Engineer may require longer sections of unslotted pipe if necessary.

Install watertight compression seals to seal the annular space between the PVC pipe and steel casing.

Identify each drain and steel casing in sequential order with a permanent marking with a stamped, non-ferrous metallic tag, (16 gauge minimum) attached with a stainless steel wire (16 gauge minimum) or other equivalent means approved by the Engineer.

(f) Initial Drain Jetting - Upon completion of installation of all the horizontal drains in a horizontal drain pad or bench level, flush the inside of the 1.5 inch PVC drain pipe with water.

Use a jet nozzle on the end of a tube inserted the full length of the drain pipe to accomplish the flushing. Operate water jet during insertion and removal of the jetting hose and nozzle to flush possible blockages within the pipe and pipe slots. Apply water pressure between 2,500 and 5,000 psi to advance the jet nozzle the full distance of the drainpipe.

(g) Drain Sequencing – Install drains in the stages and phases as directed by the Engineer.

00431.43 Drain Length - Probe the entire length of all completed horizontal drains to ensure the drain is free of obstructions, soil, breakages, and misaligned or failed connections for its entire length. If blockages are encountered, attempt to clear obstructions using the jet nozzle apparatus. Any drain pipe which cannot be installed for the full length of the drilled hole, or any drain pipe which is determined to be plugged, separated or damaged inside will be rejected and replaced at no additional cost to the Agency at locations determined by the Engineer.

Provide means to measure drain pipe during jetting at least to the nearest foot. Verify final drain length by jetting, or by inserting a smaller diameter pipe full length upon completion of drilling. Notify the Engineer five (5) days prior to jetting for measurement of horizontal drain length.

00431.44 Site Restoration - Clean drilling site of all accumulations of drill cuttings, waste, rubbish, and miscellaneous debris, and dispose of according to 00290.20. Comply with the Project erosion and sediment control plan.

00431.80 Measurement - Work performed under this Section will be measured according to the following:

(a) Horizontal Drains - Horizontal drains will be measured on the length basis for the length of the completed horizontal drain confirmed to be free of obstructions as determined by jetting operations or by inserting a measurement pipe within the horizontal drain pipe. The length of drain pipe will be measured to the ground surface. Where intermediate drain lengths are specified, the initial outfall configuration will be taken as the ground surface.

Horizontal drains with failed or misaligned connections and drain pipe breakages will not be measured.

(b) Steel Casing - Permanent steel casing will be measured on the length basis. The length of steel casing will be measured to the ground surface. Where intermediate drain lengths are specified, the initial outfall configuration will be taken as the ground surface.

(c) Drain Orientation Readings – Drain Orientation readings will be measured on the unit basis for each set of azimuth, inclination, and length readings as specified or directed.

00431.90 Payment - The accepted quantities of work performed under this Section will be paid for at the Contract unit price, per unit of measurement, for the following items:

Pay Item Unit of Measurement

(a) Horizontal Drains ............................................................... Foot

(b) Steel Casing ...................................................................... Foot

(c) Drain Orientation Readings .............................................. Each

Item (a), Horizontal Drains, includes drilling equipment and supplies, compression seals, drain outfall, PVC pipe & fittings, clamps & connections, drain outlet hoses, drill cutting removal, elevation measurements, and initial drain jetting.

Item (b), Steel Casing, includes additional drilling equipment for casing installation, steel casing, cutting shoes, and welding as necessary.

Item (c), Drain Orientation Readings, obtaining and reporting all drain orientation readings at identified horizontal drains.

Erosion control will be paid according to 00280.

Earthwork will be paid according to 00231 and 00330.

Payment will be payment in full for furnishing and placing all materials, and for furnishing all equipment, labor, and incidentals necessary to complete the work as specified.

SECTION 00445 - SANITARY, STORM, CULVERT, SIPHON, AND IRRIGATION PIPE

Comply with Section 00445 of the Standard Specifications modified as follows:

00445.80 Add the following subsection:

(k) 8 Inch Storm Sewer Pipe Assembly - The quantities of pipe assemblies will be measured on the unit basis.

00445.91 Payment – Modify the following bullets as follows:

(b) 12 Inch Storm Sewer Pipe (HDPE)............................................................................. Foot

(b) 24 Inch Storm Sewer Pipe (HDPE)............................................................................. Foot

(d) Pipe Wyes, 12 inch x 12 inch...................................................................................... Each

(d) Pipe Wyes, 12 inch x 24 inch...................................................................................... Each

(h) Pipe Slope Anchor, Metal, 12 Inch ..................................................Each

(h) Pipe Slope Anchor, Metal, 24 Inch ..................................................Each

Add the following Pay Item to the Pay Item list:

(n) 8 inch storm sewer pipe assembly ..................................................Each

Add the following paragraph after the paragraph that begins "Item (l) includes all additional Work…":

Item (n) includes all costs associated with furnishing the HDPE pipe, clamps and t-posts, including all necessary fabrication. No separate or additional payment will be made for pipe length.

SECTION 01030 - SEEDING

Comply with Section 01030 of the Standard Specifications modified as follows:

01030.13(f) Types of Seed Mixes - Add the following to the end of this subsection:

Provide the following seed mix formulas:

• Permanent Seeding:

Botanical Name PLS ÷ (% Purity x % Germination) = Amount (Common Name) (lb/acre) (minimum) (minimum) (lb/acre)

Beckmannia syzigachne (American sloughgrass) 2 ____ ____ ____ Hordeum brachyantherum (Meadow Barley) 5 ____ ____ ____ Festuca rubra (Red fescue) 4 ____ ____ ____ Deschampsia cespitosa (Tufted Hairgrass) 1 ____ ____ ____ Carex obnupta (Slough sedge) 4 _____ ____ ____ Eleocharis palustris (Creeping spikerush) 2 _____ ____ ____ Achillea millefolium

(Western Yarrow) 2 _____ ____ ____ Lupinus rivularis (Riverbank lupine) 2 _____ ____ ____

01030.13(g) Availability - Add the following sentence to the end of this subsection:

Submit the seed and seed mixes to be used on the project according to 00150.37.

Add the following subsection:

01030.15 Mulch - Add the following paragraph and bullets to the end of this subsection:

Furnish straw mulch for all temporary roadside erosion control seeding, except hydromulch may be used under the following conditions:

• Spring planting west of the Cascades between March 1 and May 15.

• Slopes are steeper than 1V to 1.5H and longer than 16 feet.

• Residential or commercial sites with low erosion potential such as sidewalk, median, or parking lot planter strips.

Projects that have variable slopes may include straw mulch and hydromulch when approved.

SECTION 02415 - PLASTIC PIPE

Comply with Section 02415 of the Standard Specifications.