Appendix_B2_-_Specifications.pdf

APPENDIX B2 – SPECIFICATIONS

NPDES OAK RIDGE PARK EAST STREAM RESTORATION ITB #27-009

1.0 CRITICAL PATH METHOD SCHEDULE

This work shall consist of planning, scheduling, and constructing the project using a Critical Path Method

Project Schedule (CPM). All work including, but not limited to, submittals, major procurement, delivery, and construction activities shall be included. All activities, including bid items, quantified in the Contract

Documents shall be included. The CPM should be based upon the entirety of the Contract Documents.

A scheduling representative shall be designated prior to submission of the CPM schedule. This person shall be responsible for all matters regarding the schedule, including developing and maintaining the schedule. The scheduling representative shall remain the same for the duration of the project unless otherwise approved by the County.

CPM SCHEDULE

The CPM Schedule shall consist of:

1. A time scaled diagram of acceptable scale and format that is acceptable to the Engineer.

Clearly label and identify each activity. Show all relationships between activities.

2. Tabular reports with activities sorted as follows:

• Activity ID. Provide predecessors and successors for each activity with leads and lags shown.

• Activity ID. Provide and clearly define the resources assigned to each activity.

• Early Start, Total Float.

• Total Float, Early Start.

• Project Area (if applicable).

• Project Phase (if applicable).

• Responsibility, e.g. Contractor, specific subcontractor, specific supplier, the

County, etc.

• Provide the header of each tabular report: the project name, Contract number, data date, run date and number, and report type.

• Provide in the body of each report: the activity identification, activity description, original and remaining duration, early/late start and finish dates, percent complete, actual start/finish dates, total float, and calendar designation for every activity.

3. Written Narrative (WN). Comply with the requirements described hereinafter.

4. Printed Calendars. Include a listing, description, and calendar form tabulation of all calendars used. Include the total number of anticipated work days required to complete the

Contract work. Delineate holidays and anticipated nonwork days or periods. Explain in the

WN the basis for determining each nonwork day or period.

5. A data disc containing all of the information contained in the CPM in a format specified by the County. Provide a duration of at least 30 calendar days for activities required for review and approval of working drawings and materials by the County. A short list of highly critical approval activities may be submitted. The Engineer will make every effort to expedite the approval of these submittals; however, this will not alter the requirement to include 30 calendar days for all approvals. Schedule the duration for activities such as curing and pre-load in calendar days. Durations for procurement activities will be evaluated on a case-by-case basis.

The latest calculated early finish date in the CPM shall equal the calendar date for completion specified in the Contract Documents. If an earlier completion date is submitted, the County will issue a change order to adjust the Contract time to the completion date shown on the CPM.

Resource load all construction activities in the schedule with the material, equipment, and manpower planned to be utilized in accomplishing each activity. Provide a full explanation of the resource loading in the WN.

The Engineer reserves the right to specify the number of activities and to require an additional breakdown of the activities at any time.

Utilize activity codes to categorize activities by at least the following: project area; project phase; and responsibility, e.g. Contractor or specific subcontractors.

Provide a WN as part of the CPM. Explain the sequence of work, the critical path, interim completion dates, project phasing, nonwork days or periods, maintenance of traffic (if applicable), and labor and equipment resources. Explain how the CPM provides for permit requirements, environmental requirements, coordination with other public Contractors, milestone dates (for the Contract or other related contracts), coordination with other entities, coordination with all utility companies, special nonwork days or periods, and weather. Explain the specific scope of each activity and the basis used to determine the original duration of each activity, i.e. Production rates and anticipated quantities.

Address all activities quantified in the Contract Documents. Explain the following in the WN:

1. Relationships between activities not obviously identified.

2. Equipment usage and limitations.

3. Manpower usage and limitations.

4. Use of additional shifts and overtime.

5. Activity codes, abbreviations, and activity identification system.

6. All calendars utilized in the CPM.

7. Date or time constraints.

8. All abbreviations.

9. Use of calendars.

10. Scheduling of weather and temperature sensitive activities.

Complete and submit the proposed CPM within 30 calendar days after receiving the Notice of Award.

Submit five sets of all required information for review and acceptance. Do not start any work until the

CPM is accepted by the County. Upon issuance of the Notice to Proceed, the start date utilized in the

CPM will be adjusted to comply with the Notice to Proceed.

The Engineer will complete the review of the CPM within 30 calendar days after submittal. If required, a meeting will be convened at which time the Engineer and Contractor may make corrections and adjustments to the proposed CPM. If a revision is necessary, submit the proposed revision within seven calendar days after receiving the Engineer’s review comments or within seven calendar days after the date of the meeting, whichever is the latest. Make revisions in accordance with the requirements for the CPM. The Engineer will respond to the revised CPM within seven calendar days after receipt.

Any delay in starting work caused by the acceptance of the CPM by the Engineer will not be considered as a basis for any adjustment in the Contract amount or time.

Upon notification that the CPM has been accepted, that document will become the CPM of record.

The CPM of record shall be the Contractor’s work plan for completing the entire Contract as specified in the Contract Documents.

Failure to adhere to the CPM of record will be cause for the County to deny requests for additional compensation or extensions of the Contract duration and may result in the withholding of pay estimates.

CPM UPDATES

Provide monthly updates of the CPM of record. Update submissions shall include the activity data as specified above. Use the update to describe the progress to date. The WN shall include a description of the work performed during the update periods, current critical path, the amount of float on the critical path, any delays or disruptions experienced during the period of the update, any change in manpower or equipment, and any potential delays or disruptions.

The scheduling representative and the Engineer will meet to review, mutually agree to, and sign-off on the information required to update the schedule (actual start and finish dates, remaining durations, and percentages complete). Use an acceptable update form. The data date for each update shall be seven days prior to the cut-off date of the pay estimate for that month. Submit the update within seven calendar days from the data date. Failure to submit the update on a timely basis may result in the withholding of pay estimates. Upon acceptance by the Engineer, the update shall become the CPM of record for the period between its data date and the data date of the next approved update or revision.

Do not include any revisions to the CPM without prior approval.

REVISIONS TO THE CPM OF RECORD

Revisions are defined as one or more of the following:

1. A change in the original duration of an activity.

2. A change in the logic of the schedule.

3. A change in the calendars or to the calendar to which an activity is assigned.

4. A change to resources.

5. A change to any actual date, previously established.

6. The deletion or addition of an activity.

7. A change to, addition of, or deletion of a date or time constraint.

8. A change to, addition of, or deletion of an activity code.

9. A change to an activity description.

10. Any change other than updating an activity.

Discuss any proposed revision to the CPM verbally with the Engineer. If the revision is minor in nature, the Engineer may allow the revision to be included on the next Update of the CPM. If the Engineer determines that the revision is not minor in nature, submit the proposed revision for review and approval prior to deviating from the approved CPM.

When a revision to the CPM is required due to changes in the Contract initiated by the Engineer, immediately contact the Engineer to discuss the changes. If the revision is minor in nature, the Engineer may allow the revision to be included on the next Update of the CPM. If the Engineer determines that the revision is not minor in nature, submit the proposed revision for review and approval prior to deviating from the approved CPM.

The Engineer may allow a deviation from the approved CPM for specific mitigating activities.

Submit the proposed revision in the same format and with the same requirements used for the initial

CPM. The proposed revision shall be made to the CPM of record at the time the revision is made, i.e.

the revision shall include all update information and revisions previously approved and the additional progress to the date of the revision.

The WN accompanying the proposed revision shall describe the reason for the revision, the resulting critical path, and all particulars of the revision. These shall include but not be limited to changes in the method or manner of the work, changes in specifications, changes in resources, addition or deletion of work, increased or decreased quantities, defective work, and acceleration of the work.

The Engineer will review and respond to the proposed revision within 14 calendar days after receipt.

Resubmit, if required, within seven calendar days after receipt of the Engineer’s review comments.

The County reserves the right to reject any proposed revision that adversely impacts the County, utilities, or other concerned parties.

EXTENSIONS OF CONTRACT TIME OR INCENTIVE/DISINCENTIVE DATE

Make requests for extension of Contract time in writing and subject to the notice and timeliness of submission provisions as provided for elsewhere in the Contract. Requests for an extension of Contract time or change in an incentive/disincentive date will be evaluated by the Engineer’s analysis of the

CPM of record and any proposed revision submitted. The request shall include a WN of the events, which would require an extension of the Contract time or incentive/disincentive date.

Only delays to activities that affect the Contract completion date or incentive/disincentive date will be considered for an extension of Contract time. The extension of the specified Contract completion date or incentive/disincentive date will be based upon the number of calendar days the Contract completion date or incentive/disincentive date is impacted as determined by the Engineer’s analysis.

When an acceptable Update or Revision is not submitted within the time limits prescribed above, pay estimates may be withheld until an acceptable Update or Revision is submitted.

2.0 MOBILIZATION & DEMOBILIZATION

Refer to Division I, Section 01100 of Charles County Standard Specifications for Construction dated

May 1996, and subsequent revisions thereto, with the following modifications:

01100.01 GENERAL

A. Description

ADD the following to 01100.01.A:

Restoration of damages to existing sidewalks, curbs, gutters and roadways that occurs as a result of construction other than areas outside of proposed improvements as shown on the Contract

Drawings shall be included under this item.

01100.02 MATERIALS

REPLACE 01100.02 with the following:

A. Restoration of Sidewalks

REFER to 02660.02

B. Restoration of Curbs and Gutters

REFER to 02670.02

C. Restoration of Pavement

REFER to 02680.02

01100.03 EXECUTION

ADD the following to 01100.03:

A. Restoration of Sidewalks

REFER to 02660.03

B. Restoration of Curbs and Gutters

REFER to 02670.03

C. Restoration of Pavement

REFER to 02680.03

3.0 CONSTRUCTION STAKEOUT

Construction Stakeout shall be in accordance with Section 01300 – Construction Stakeout of the Charles

County Department of Planning and Growth Management, Standard Specifications for Construction

(dated May 1996), unless noted otherwise on Contract Documents.

GENERAL

A. Furnish, place and maintain construction layout stakes and install monuments for the purpose of post-construction monitoring efforts, as specified by the Engineer.

B. Provide and have available to the project an adequate engineering staff which is competent and qualified to set all lines and grades needed to construct the stream restoration.

C. Make all field measurements necessary to stakeout the baseline of construction and lay out the lines and grades called for in the Contract Documents or as directed by the Engineer.

D. Set, preserve, and utilize benchmarks shown on the Contract Drawings for construction. The

Contractor shall be held responsible for preservation of the benchmarks. If, in the opinion of the

Engineer, the benchmarks are willfully or carelessly disturbed or destroyed by the Contractor or their employees, the entire cost of replacing them will be charged against the Contractor and the cost will be deducted from the Contractor’s final payment.

E. Demarcate the Limit of Disturbance (LOD) to the satisfaction of the Engineer, as part of the construction stakeout operation and before any clearing operation commences. These areas will be verified by the Engineer.

F. To assist the Contractor in survey and stakeout, electronic design CAD files will be provided to the Contractor at the pre-construction meeting by the Engineer. These files should be used to correctly demarcate the LOD, and/or protected resources including wetlands and trees to be protected in the field.

G. Notify the Engineer once the stakeout or any phase of the stakeout is completed. The Engineer will inspect the construction stakeout prior to the Contractor beginning clearing and grubbing activities.

The purpose of the inspection is not to verify the stakeout, but to allow the Engineer an opportunity to assess the lines established by the Contractor, prior to the start of construction. Obvious errors with the stakeout will be remedied prior to the Contractor proceeding with construction. This inspection will in no way relieve the Contractor of their responsibilities to construct the site as specified in the Contract Documents.

H. The existing elevations and contours shown on the plans, cross sections, stream bottom profiles, and/or bank alignment shown on the Contract Drawings were correct when surveyed. However, because of interim stream erosion, sediment accretion, and possible fill, existing elevations and grades may have changed since the original survey was completed. It is the Contractor’s responsibility to confirm existing grades and adjust quantities, earthwork and work efforts as necessary at no additional cost to the County.

MATERIAL

A. For stream baseline stakeout, the Contractor will furnish a staked baseline of construction of the proposed location of the stream, storm drain structures, and storm drain pipe as depicted on the plans, with the spacing of stations (stakes, nails, crosses, etc.) not to exceed 25 feet. Additionally, all points of curvature (PC) and points of tangency (PT) must be staked.

B. For stream structures, the Contractor will furnish appropriately spaced benchmarks and the necessary references required to locate all stream structures in the Contract Documents.

EXECUTION

A. The LOD shall be demarcated using stakes, and non-tidal wetlands and trees to be protected as shown on the Contract Drawings shall be demarcated using flagging. No clearing or earth disturbance activity may begin until the LOD, non-tidal wetlands, and trees to be protected as shown on the Contract Drawings have been demarcated. The Contractor shall be responsible for maintaining flagging throughout the duration of the project and shall replace flagging as directed.

B. For stream baseline stakeout, the Contractor will furnish, set, and preserve stakes or other suitable markers along the baseline of construction, as depicted on the plans, with the spacing of stations not to exceed 25 feet and all points of curvature (PC) and points of tangency (PT). The top elevation should be recorded on each stake. The Contractor shall set additional stakes as needed for horizontal and vertical controls necessary for the correct layout of the work. The Contractor will establish appropriately spaced benchmarks and the necessary references including all PC and all PT for the preservation and control of the baseline of construction. Upon completion of the grading, the Contractor will provide the County, upon request, with a staked baseline of construction.

C. For stream structures, the Contractor will furnish and set appropriately spaced benchmarks required to locate all stream structures indicated on the Contract Documents. The Contractor will check the proposed structure lengths by electronic distance measurement or chaining from the field layouts. Compensate measurements for horizontal alignment when chaining is used. Check the location of structures to verify its correct location with relation to existing on-site features and conditions that are to remain in the original positions.

D. For storm drain structures, the Contractor will furnish and set appropriately spaced benchmarks required to locate all storm drain structures indicated on the Contract Documents. The Contractor will check the proposed structure lengths by electronic distance measurement or chaining from the field layouts. Compensate measurements for horizontal alignment when chaining is used. Check the location of structures to verify its correct location with relation to existing on-site features and conditions that are to remain in the original positions.

E. The Contractor shall notify the Engineer of any discrepancies at once in writing; otherwise, all planned dimensions, grades, and field measures will be deemed correct. All lines established on the ground will be preserved or references, marked, and kept available at all times.

4.0 MAINTENANCE OF TRAFFIC

Refer to Division I, Section 01410, of Charles County Standard Specification for Construction dated

01410.01 GENERAL

ADD the following to 01410.01.A:

4. The Contractor shall provide for Maintenance of Traffic as shown on the approved Contract

Drawings, in accordance with all local laws and regulations and as directed by the County.

Warning signs and pedestrian traffic detour signs shall be installed according to applicable

MDSHA and Charles County traffic control requirements.

5. Temporary flaggers are required during all deliveries and all heavy equipment movement within the activity area and/or public rights of way.

ADD the following to 01410.01.D:

The Contractor shall submit a Certification of Compliance with applicable state standards for all traffic control devices.

5.0 PROTECTION OF THE ENVIRONMENT

Refer to Division I, Section 01500, of Charles County Standard Specification for Construction dated

01500.01 GENERAL

C. Standards

REPLACE 01500.01.C with the following:

All work shall be performed in accordance with the "2011 Maryland Standards And Specifications For

Soil Erosion And Sediment Control" as adopted by the Charles Soil Conservation District and the State of Maryland Department of the Environment and all subsequent changes and addenda in effect at the time of receipt of Bids, as the official guide for erosion and sediment control measures for projects in

Charles County.

E. Permits and Agreements

REPLACE 01500.01.E.1 with the following:

a. The County has obtained Soil Conservation District approval for the Project, the conditions which are hereby incorporated into the Contract Documents. It is the Contractor's responsibility to meet all terms and conditions during the performance of the work.

b. The County has obtained all Waterway Construction Permits from the Maryland Department of the Environment for any applicable construction within wetlands and/or flood plains of the waters of the State of Maryland and such permits as may be applicable from the United States

Army, Corps of Engineers for construction within navigable waters. These permits, if applicable, are hereby incorporated into the Contract Documents, and it is the Contractor's responsibility to meet all terms and conditions of the permits during the performance of the work.

01500.02 MATERIALS

C. Detailed Material Requirements

REPLACE the first sentence of 01500.02.C.3 with the following:

a. For use in riprap pipe outlets.

1) Fabric shall consist of long chain polymeric filaments or yarns of polypropylene, polyethylene, polyester, polyamide or polyvinylidene-chloride formed into a stable network.

2) Fabric shall be inert to chemicals commonly encountered in soil and to hydrocarbons.

3) Fabric shall be resistant to mildew, rot, insect and rodent attack.

4) Fabric shall contain ultraviolet ray inhibitors and stabilizers and be suitable at temperatures of

0°F to 120°F.

5) Fabric shall conform to the following test criteria:

Test and Method Specification Limits

Grab Tensile Strength, ASTM D 1682, lbs min 90

Tensile Elongation, ASTM D 1682, % min 20

Burst Strength, ASTM D 3786, psi min 140

Trapezoidal Tear Strength, ASTM D 117, psi min 45

Equivalent Opening Size, U.S. Standard Sieve Size, 40-100 as shown

CW-02215 Corps of Engineers on the Plans

Flow Rate, AASHTO M 228 Appendix, gpm/sq ft min 40

Coefficient of Permeability, AASHTO M 228 0.05

Appendix, cm/sec min

6) Prefabricated silt fence units of the trade name Geofab or Envirofence or equal, at the

Contractor's option, may be used in lieu of an on-site fabrication inlet barrier.

ADD the following to 01500.02.C:

4. Silt Fence

a. Silt Fence Fabric

1) Fabric may be either woven or nonwoven.

a) Nonwoven fabric shall consist of long chain polymeric filaments or yarns of polyester

b) Woven fabric shall consist of mono filaments of polypropylene treated with ultraviolet light stabilizers.

2) Fabric shall be inert to chemicals commonly encountered in soil and to hydrocarbons.

3) Fabric shall be resistant to mildew, rot, insect and rodent attack.

4) Fabric shall contain ultraviolet ray inhibitors and stabilizers and be suitable at temperatures of 0°F to 120°F.

5) Fabric shall conform to the following test criteria:

Test and Method Specification Limits

Grab Tensile Strength, ASTM D 1682, lbs min 90

Tensile Elongation, ASTM D 1682, % min 50

Tensile Elongation, ASTM D 1682, % max 115

Burst Strength, ASTM D 3786, psi min 190

Puncture Strength, ASTM D 751, lbs min 60

Flow Rate, AASHTO M 228 Appendix, gpm/sq ft min 40

Ultraviolet Radiation Stability, ASTMG 26, % 90

Coefficient of Permeability, AASHTO M 228 0.1

Appendix, cm/sec min

Equivalent Opening Size, U.S. Standard Sieve Size, 40-100 as shown

CW-02215 Corps of Engineers on the Plans

b. Fence Posts (for fabricated units): The length shall be 36 inches minimum. Wood posts will be of sound quality hardwood with a minimum cross sectional area of three square inches.

Steel posts will be standard "T" and "U" sections weighing not less than 1.33 pounds per linear foot with a minimum length of 42 inches.

c. Wire Fence (for fabricated units): Wire fencing shall be a minimum 14-1/4 gauge welded wire fabric with a maximum 6-inch mesh opening, or as approved.

d. Prefabricated Units, at the Contractor's option, may be used in lieu of the fabricated site fence. The prefabricated unit shall be Geofab or Envirofence or equal and shall be installed per manufacturer's instructions.

5. Temporary Seeding and Mulching

a. Lime: ground dolomitic limestone containing not less than 85% calcium and magnesium carbonates with at least 10% magnesium as magnesium oxide. The ground limestone shall meet the following gradation:

Sieve Size Percent Passing

No. 10 100

No. 20 98

No. 100 50

b. Fertilizer: standard commercial grade 10-10-10 or equivalent.

c. Seed: Perennial rye, Italian rye - (February 1 through April 30 or August 15 through November 1). Millet - (May 1 through August 15).

d. Mulch and mulch binders shall be as specified in Section 02820. From November

2 through January 31, use mulch only.

6. Temporary slope drains may be constructed of material acceptable to the Engineer, and shall be furnished with watertight joints.

7. Straw Bales shall consist of undecayed firmly-packed straw of nominal size 14 inches by

18 inches by 36 inches as prepared by any standard make baling machine and firmly bound by at least 2 separate circuits of rope or band material which will withstand weathering for a minimum of 3 months. Binding tension shall be set so as to produce a bale with voids no greater than the nominal thickness of the straw.

8. High Visibility Fence:

a. Mesh shall be international orange, high density polyethylene diamond mesh with a mesh opening of 1½ inches. Mesh shall be four (4) feet in height with a roll weight of 20 pounds per roll and roll size of four (4) feet by 50 feet.

b. Posts shall be a conventional metal “T” or “U” post.

c. Rope, tension wire or other band material used to secure mesh to posts or as a stringer between posts shall be able to withstand weathering for a minimum of three (3) months.

9. Temporary Construction Access Road, Staging and Stockpiling Areas

a. Temporary Construction Access Road, Staging and Stockpiling areas shall be wood mulch. The Contractor may substitute an equivalent material such as stone or timber mats provided it is approved by the County and the Sediment Control

Inspector. The Temporary Construction Access Road, Staging and Stockpiling areas shall be a stable firm material that does not promote the migration of site materials (including the path itself) from the site, or leach toxins.

b. Mulch shall be wood chips or shredded wood and meet the applicable material specifications of 02820.02.C.4. All mulch will be free from invasive species.

c. With County approval, geotextile may be installed under Mulch and shall be as specified in 01500.02.C.3.a for use in stabilized construction entrances and temporary access water crossings. The Contractor may substitute an equivalent material provided it is approved by the County.

10. Tree Planking:

a. The wooden planks shall be hardwood and a minimum of two (2) inches thick.

b. The gauge wire shall be 10 gauge and galvanized.

11. Temporary Access Bridge:

a. Use stringers consisting of logs, sawn timber, prestressed concrete beams, metal beams, or other approved materials.

b. Select decking materials to provide sufficient strength to support the anticipated load.

12. Temporary Chain Link Fence:

a. Temporary Chain Link Fence shall meet the following specifications:

1) Galvanized Steel Construction

2) Corrosion-Resistant Zinc Coating

3) ASTM A392-06 Standards Compliant, CSI 01 56 26

4) Line Post: 1 5/8”

5) 6’ Height

b. Contractor shall provide submittal with post/base per manufacturer recommendations.

01500.03 EXECUTION

REPLACE 01500.03 with the following:

R. Temporary Chain Link Fence

1. Areas where Temporary Chain Link Fence is to be installed shall be designated by flagging in the field prior to scheduling the preconstruction meeting.

2. The contractor shall erect Temporary Chain Link Fence as designated on the Contract

Drawings and/or as specified by the County prior to the beginning construction.

3. Posts shall be spaced per manufacturer’s specifications. The Temporary Chain Link and posts shall be removed at the end of the contract with the approval of the County. The fence and posts shall become the property of the Contractor at the completion of the project.

4. The Contractor shall maintain the Temporary Chain Link Fence in good repair throughout the duration of the construction.

c.

01500.03 EXECUTION

REPLACE 01500.03 with the following:

A. General

1. The Contractor shall be responsible for installation, maintenance, and removal of all items for the implementation of the work described herein for environmental protection including prevention and control of erosion and sedimentation that results directly or indirectly from all work performed during construction and until the final acceptance at the end of the one-year guarantee period as described in Section GP5.11.2.

2. Prior to the start of any construction effort, the Contractor shall submit his schedules, which shall include and be compatible with the Sediment Control Plan Phasing

Schedules, and sequences for accomplishing environmental protection including temporary and permanent erosion control work as is applicable to the clearing and grubbing, excavation, grading, utility installation, structure construction, paving, and permanent stabilization and landscaping phases of the project. No work shall be started until the schedules and methods of operation have been accepted by the Engineer.

B. Prevention of Water Pollution

1. The Contractor shall take all such precautions in the conduct of his operations as may be necessary to avoid contaminating the water in adjacent watercourses or water storage areas, including wells, whether natural or man-made.

2. All earthworks, moving of equipment, water control for excavations, and other operations likely to create silt, shall be conducted so as to prevent pollution of watercourses or water storage areas.

3. Water used during the conduct of any operations, which has become contaminated with oil, bitumens, harmful or objectionable chemicals, sewage, or other pollutants shall be disposed of so as to avoid affecting all nearby waters and lands. The Contractor shall not discharge pollutants into a watercourse or water storage area under any circumstances.

The Contractor shall not allow water used in aggregate processing, concrete curing, foundation and concrete cleanup, or any other waste to enter a stream. When water from adjacent sources is used in the Contract work, intake methods shall be such as to avoid contaminating the source of supply or becoming a source of erosion.

C. Dust Control

Throughout the entire construction period, the Contractor shall maintain dust control by use of water sprinklers or chemical dust control binder as may be approved or directed by the Engineer.

D. Erosion and Sediment Control

1. The Contractor shall shape the graded areas in a manner as to permit the runoff of precipitation. Temporary earth berms shall be constructed along the top edges of embankments to intercept runoff water. Temporary slope drains shall be provided to carry runoff from cuts and embankments as shown on the Approved Sediment Control

Plan. Slope drains may be constructed of flexible or rigid materials and should be capable of being readily shortened or extended as the excavation or fill advances. Pipe end sections or other approved entrances shall be provided at the slope drain entrances.

Energy dissipaters shall be provided at drain outlets where indicated on the Plans and where demonstrated to be necessary during the term of the project. Temporary slope drains shall be outletted only into stabilized areas or sediment control devices.

2. Only those areas that are so designated shall be cleared and, where possible, a vegetative buffer zone between the disturbed working area and any watercourse shall be maintained.

3. Excavated material shall be protected from being eroded into any waters or onto any adjacent lands. Excavated material shall be stockpiled on the high side of trenches.

4. When sediment control devices are designated on the Plans, they shall be installed during the initial grading and clearing operations and be completed before trenching operations begin. They shall be maintained until final restabilization and restoration or until directed by the Inspector/ Engineer to remove them.

5. Critical areas, disturbed areas with a surface gradient exceeding ten percent, shall be immediately stabilized with vegetation after excavating or backfilling operations are completed. Those areas that cannot be planted shall be adequately covered with straw mulch, wood chips, matting, or other erosion prevention materials. Those disturbed areas that are less than 10% in surface gradient shall be considered critical after diverting runoff from critical areas.

6. Erosion control measures such as straw bale dike, earth berm dike, pipe, or other diversion devices to divert and/or convey runoff around or through disturbed areas to prevent scour or gully erosion shall be provided. Pipes shall be provided with end sections and protected outlets.

7. A stone or paved entrance shall be provided at all points of egress onto public thoroughfares to provide a controlled location for the inspection of vehicles and the cleaning from the vehicles of all material which might be tracked from the site or lost from the vehicle when it enters onto the public thoroughfare.

8. Streams with a base flow shall only be crossed by one of the following methods:

a. Fluming of water around construction.

b. Pumping of water around construction.

c. Temporary stream diversion within the confines of the existing channel.

d. Tunneling of the stream.

9. When utilizing a stream diversion flume within a large stream that requires a working area to be constructed in the stream, the initial diversion shall be constructed of non-erodible materials such as stone, sandbags, wood planking, or soil protected with stone or sandbags. The non-erodible material shall be placed upstream prior to constructing the working area. All soil used in the stream crossing shall be protected from the forces of the water in the channel with non-erodible materials approved by the Engineer. After completing the crossing, all materials associated with the temporary construction shall be removed.

10. All temporary sediment control devices that are disturbed during the construction operations shall be fully repaired by the end of that working day.

11. Construction operations shall comply with the requirements specified herein and/or as shown on the Plans. Violation of these requirements may result in suspension of the

Work. Suspension of Work will not be lifted until the Contractor has corrected the violation. Time extensions requested as a result of delays occasioned by such suspensions will not be granted.

12. Should conditions arise that render the Erosion Sediment Control Plans inadequate or inappropriate in whole or part for work included in the Contract, the Contractor shall immediately notify the Engineer and the Charles Soil Conservation District.

Additional plans or modifications where necessary will be furnished by the County and will become part and condition of the Sediment Control Permit.

E. Restabilization and Restoration

1. Construction clean up shall proceed as construction progresses and shall consist of the removal of all mud, oil, soil, gravel, trash, debris, and any other materials that are unsightly or can cause or result in erosion.

2. All areas disturbed by the Contractor's operations, including staging and stockpiling areas, construction strips, access roads, stream crossing sites, and areas within the acquired rights-of-way and easements shall be restored and restabilized as specified herein.

3. Final restoration and restabilization including seeding, sodding, and paving, when season permits, shall proceed immediately after construction activity is completed in a given area. The Contractor shall remove all temporary construction facilities constructed by the Contractor and leave the site in an orderly condition.

4. Tree protection, repair, and replacement shall be performed in accordance with Title 8, Subtitle 07, Chapter 02, Maryland Forest Service, and Roadside Tree Care.

5. Sod shall be provided on those disturbed areas designated on the Plans which supported a previously established stand of turf as directed by the Engineer. Seeding and mulching shall be provided on all other disturbed and graded areas.

6. Separate agreements between the Contractor and property owners for clean-up, grading, seeding, sodding; and tree repair, removal, or replacement shall be submitted in writing to the Engineer prior to commencement of any work.

7. Public and private signs, markers, guardrails, and fences shall be preserved and maintained in their original condition unless written permission is obtained for removal and replacement. Such conflicting facilities shall be removed when grading operations begin, stored in a manner to keep them clean and dry, and re-erected at such new locations as to prevent damage to underground or overhead public utility facilities.

Damaged items shall be replaced by the Contractor at no cost to the County.

8. Restabilization of turf areas shall be performed in accordance with Section 02820.

9. Gravel surfaces and shoulders shall be restored to original condition. Shoulder material shall not be reused if contaminated by foreign material. In such case, replace with new material of same quality and gradation. Materials and methods of construction shall be in accordance with Sections 02280 and 02630 and with applicable permits secured for this Contract.

F. Disposal of Waste Materials

1. Construction waste materials shall be disposed of by the Contractor in an authorized disposal area or in an area covered by a current grading or sediment control permit.

2. Waste material disposed of in an unauthorized area shall be removed by the Contractor and the area shall be restored to its original condition, at no cost to the County.

G. Sequence of Construction

1. In general, sediment control devices shall be installed prior to beginning any other earthwork under the Contract.

2. Inlet protection devices shall be installed immediately after new inlet boxes are constructed. Disturbed areas shall be stabilized and sediment control devices removed as soon as practical. The Contractor will be solely responsible, during the time the sediment control device is in place, for any damage resulting from the diversion of stormwater, which would normally be intercepted by the existing inlet.

3. Silt fences and high visibility fences shall be constructed prior to beginning any other earthwork. Maintenance of silt fences, high visibility fences, etc. is required regularly to assure sediment storage volume and integrity of the individual practices.

4. Silt fences shall not be removed until graded areas are permanently stabilized.

5. Cut and fill slopes shall be dressed, prepared, and seeded as the work progresses. The slope stabilization shall be completed in vertical increments of not more than 10 feet as the grading operations proceed and immediately following the suspension of grading operations in any area.

6. Permanent or temporary stabilization of all contributing drainage areas is to be established prior to the removal of erosion control measures. The stabilized construction entrance shall not be removed until the entire site is stabilized or until the need for all access has passed.

H. Wheel Washing

When directed, vehicle wheels shall be cleaned by the Contractor to remove sediment prior to entrance onto public rights-of-way. When washing is required, it shall be done on an area stabilized with crushed stone, which drains into an approved sediment trap or sediment basin. All sediment shall be prevented from entering any storm drain, ditch, or watercourse.

I. Silt Fences

1. Silt fences shall be constructed by the Contractor where indicated on the Plans and in accordance with the 2011 Maryland Standards and Specifications for Soil Erosion and

Sediment Control.

2. Welded wire fence fabric shall be fastened securely to the fence posts using wire ties or staples.

3. The cloth shall not be installed in a stretched condition but shall be installed loosely.

The panels shall be overlapped a minimum of 12 inches before fastening to the fence fabric.

4. The filter cloth shall be fastened securely to the woven wire fence fabric by wire ties spaced horizontally every 24 inches at both top and midsection.

5. The top edge of the cloth shall be reinforced or shall have a one-inch tuck.

6. If any portion of the fence or filter cloth becomes damaged, it shall be immediately repaired or replaced.

7. Accumulated silt and debris shall be removed by the Contractor from the face of the fence or whenever "bulges" in the fence develop or silt deposits reach approximately one half the height of the fabric. Clogged or damaged filter fabric shall be immediately replaced.

8. At the Contractor's option silt fences may be used in lieu of “Straw Bale Dikes”.

J. Temporary Grading

1. The Contractor shall temporarily grade the site in such a manner that runoff from the disturbed or unstabilized work areas will flow to protected inlets, sediment traps, or silt fences.

2. The ground at sediment traps shall be restored to original grades after all other earthwork is completed, the area stabilized, and the sediment control devices are removed.

K. Ground Stabilization

1. General

Following initial soil disturbance or redisturbance, the Contractor shall complete permanent or temporary soil stabilization within:

a. Seven calendar days as to the surface of all perimeter controls, dikes, swales, ditches, perimeter slopes, and all slopes greater than 3 horizontal to 1 vertical

(3:1) and

b. Fourteen calendar days as to all other disturbed or graded areas on the project site.

These requirements do not apply to those areas, which are shown on the Plan and are currently being used for material storage, or for those areas where construction activities are currently being performed.

2. Temporary Stabilization

a. The embankments and cuts around sediment traps; earth dikes; all stockpiles of topsoil or earth; and all cleared or graded areas shall be temporarily stabilized by the Contractor with seed and/or mulch.

b. Temporary seeding shall be applied to any disturbed area scheduled to be left or remaining inactive more than 15 days as follows:

1) Loosen top 2 inches of seedbed.

2) Apply lime at the rate of 50 pounds per 1000 square feet and fertilizer at the rate of 15 pounds per 1000 square feet.

3) Moisten seedbed during periods of high temperature and when directed by the Engineer.

4) Apply appropriate seasonal seed mixture uniformly at the rate of 0.92 pounds per 1000 square feet with mechanical power drawn seeders, mechanical cyclone hand seeders, or hydroseeding equipment (Slurry for hydroseeder may contain seed and fertilizer only).

5) Disc seed 1 inch into soil in floodplain areas. Rake, roll, or drag seedbed in all others areas.

6) Apply mulch in accordance with Section 02820.03.

7) Anchor mulch in accordance with Section 02820.03.

8) The Contractor shall maintain seeded areas including watering if soil moisture becomes deficient. Repair as periodic inspection by the

Contractor dictates including replacement and/or reseeding.

c. Temporary mulching only

1) Apply mulch materials uniformly by hand or mechanically at the following rates:

Straw mulch: 70 to 90 pounds per 1,000 square feet

Mulch matting: full coverage with minimum 6-inch overlap between blankets

Wood chips: 275 pounds per 1,000 square feet

Crush rock, stones or gravel: 900 to 4500 pounds per 1000 square feet with coarsest material applied at highest rate

2) Anchor mulch immediately after placement by one of the following methods:

a) Mulch Anchoring Tool: For use on slopes flatter than 3:1 only.

Use mechanical equipment operated on the surface to punch and anchor the mulch into the surface a minimum of 2 inches at each punch location. Anchorage shall be provided at a minimum of 1 location per square feet.

b) Mulch Tracking: Use tracked type construction equipment to cut the mulch into the soil with cleated type tracks to a depth of 1 1/2 inches. Tracking shall be done uniformly across the entire surface.

c) Mulch Netting: Staple lightweight biodegradable paper, plastic or cotton netting over mulch using manufacturer's recommendation for type and spacing of staples.

d) Liquid Mulch Binders: Apply liquid mulch binders uniformly to entire mulched area with heavier application rate applied along edges and where wind tends to catch the mulch, in valleys and at crests of banks. Caution shall be used to prevent damage to adjacent structures and undisturbed areas. The type of binder and the application rates may be as follows:

(1) Cutback asphalt - Apply RC-70, RC-250, RC-800, MC-

250 or MC-800 cutback asphalt at minimum rate of 5 gallons per 1000 square feet on flat areas and slopes less than 8 feet in height. On slopes 8 feet or greater in height apply at minimum rate of 8 gallons per 1000 square feet.

(2) Emulsified asphalt - Apply SS-1, CSS-1, CMS-2, MS-2, RS-1, RS-2, CDRS-1 or CRS-2 emulsified asphalt at minimum rate of 5 gallons per 1000 square feet on flat areas and slopes less than 8 feet in height. On slopes 8 feet or greater in height apply at minimum rate of 8 gallons per

1000 square feet.

(3) Synthetic binders - Apply Acrylic BCR (agri-tac), DCA-

70, Petroset or Terra Tac or equal at rates recommended by the manufacturer.

e) Wood Cellulose Fiber Binder - Apply fiber binder at a net dry weight of 750 lbs/acre using approved mechanical slurry application equipment. The slurry shall consist of a water and fiber mixture of not more than 50 pounds wood cellulose fiber per

1000 gallons of clean water.

f) Peg and Twine - The peg and twine anchorage system shall consist of 8 to 10 inch long wooden pegs driven either before or after mulch placement to within 2 to 3 inches of the soil surface at a maximum spacing of 4 feet on centers with the mulch secured to the soil surface by stretching twine between and secured to the pegs in a criss-cross within a square pattern.

3) The Contractor shall maintain as required until final grading and permanent surface stabilization is completed. Repair as periodic inspection by the Contractor requires.

4) Permanent Stabilization

a) The Contractor shall apply permanent stabilization measures to the finished grading surface of all areas disturbed by construction as soon as possible subject to the seasonal limitations for seed and shrubbery planting.

b) All areas disturbed by construction not indicated to be paved or occupied by structures shall be permanently stabilized with vegetative cover in accordance with the Special Provision

“Permanent Seeding, Fertilizing, and Mulching”.

L. Class I Small Riprap

The Contractor shall construct Class I small riprap in accordance with Section 02291.03.

M. Removal of Sediment Control Devices

The Contractor shall restore to the original grade, or construct to the finished grades as shown on the Plans, all areas on which temporary facilities were constructed and all areas disturbed by the Contractor.

N. High Visibility Fence

1. Areas where High Visibility Fence is to be installed shall be designated by flagging in the field prior to scheduling the preconstruction meeting.

2. The contractor shall erect High Visibility Fence as designated on the Contract Drawings and/or as specified by the County prior to the beginning construction.

3. Posts shall be spaced a maximum of twelve (12) feet. Rope, tension wire or other band material shall be used to secure the mesh to the post. Tension wire or rope may be used as a top stringer woven through the top row of mesh openings to prevent potential sagging.

The High Visibility Fence and posts shall be removed at the end of the contract with the approval of the County. The fence and posts shall become the property of the Contractor at the completion of the project.

4. When installing posts for tree protection, the Contractor shall avoid damaging the root system of the tree.

5. The Contractor shall maintain the High Visibility Fencing in good repair throughout the duration of the construction.

O. Temporary Construction Access Road and Staging & Stockpiling Areas

1. The contractor shall erect the Temporary Construction Access Road as designated on the

Contract Drawings and/or as specified by the County.

2. Geotextile may be installed under mulch, if approved by the County.

3. The Contractor shall strip and stockpile surface cover to a minimum depth of six (6) inches within areas to be mulched.

P. Tree Planking

1. The Contractor shall install Tree Planking around trees that are directly adjacent to the construction access or have the potential to be damaged by machinery in close operation.

2. The Contractor shall use 10 gauge wire to attach the planks to the tree trunk.

3. The Contractor shall not nail, staple or in any other way damage the tree when attaching the Tree Planking to the tree trunk.

Q. Temporary Access Bridge

1. Construct structure at or above the bank elevation to prevent impacts from floating materials and debris.

2. Place abutments parallel to, and on, stable banks.

3. Place all decking members perpendicular to the stringers, butt tightly, and securely fasten. Decking materials must be butted tightly to prevent any soil material tracked onto the bridge from falling into waterway below.

4. Securely fasten optional run planking for the length of the span. Provide a run plank for each track of the equipment wheels. Although run planks are optional, they may be necessary to properly distribute loads.

5. Install curbs the entire length of the outer sides of the deck to prevent sediment from entering the stream channel.

6. Anchor bridge securely to only one end using steel cable or chain. Anchoring at only one end will prevent channel obstruction in the event that floodwaters float the bridge.

Acceptable anchors are large trees, large boulders, or driven steel posts. Anchor must be sufficient to prevent the bridge from floating downstream.

R. Temporary Chain Link Fence

1. Areas where Temporary Chain Link Fence is to be installed shall be designated by flagging in the field prior to scheduling the preconstruction meeting.

2. The contractor shall erect Temporary Chain Link Fence as designated on the Contract

Drawings and/or as specified by the County prior to the beginning…