Supplemental_Specifications.pdf

SUPPLEMENTAL SPECIFICATIONS

ROAD AND STREET CONSTRUCTION

P.I.D. No. 003900A

Stormwater Starkey Facility M10 Modifiation (Rebid)

In Pinellas County, Florida

TO ACCOMPANY PINELLAS COUNTY STANDARD TECHNICAL SPECIFICATIONS FOR

ROADWAY AND RELATED CONSTRUCTION (JULY 2019 EDITION), AND FLORIDA

DEPARTMENT OF TRANSPORTATION (FDOT) STANDARD SPECIFICATIONS FOR ROAD

AND BRIDGE CONSTRUCTION – DIVISIONS II AND III ONLY (JULY 2021):

Modified Pinellas County Standard Technical Specification (Replaces the July 2019 Clearing and Grubbing Specification)

CLEARING & GRUBBING 110, July 2019 with the following:

The work specified under this Section consists of the clearing and preparation of sites for proposed construction, in accordance with the requirements of Section 110 of the FDOT Specifications, as amended herein. The work specified under this Section must include the removal and off-site disposal of all trees indicated on the plans to be removed, the removal and off-site disposal of all brush, stumps, roots, rubbish and debris, and all obstructions resting on or protruding through the surface of the existing ground and the surface of excavated areas, the removal and off-site disposal of all existing facilities, drainage structures, culverts, pipes, and pavement indicated on the plans to be removed, and the removal and off-site disposal of all buildings, structures, appurtenances, and other facilities necessary to prepare the area for the proposed construction.

No stock piling of material on the roadway, within tree protection zones (TPZ), or on the sidewalk is allowed. All extra dirt and/or debris must be removed daily as part of the daily clean-up process.

The roadway and the sidewalks must be swept daily. All costs associated with daily clean-up process and sweeping must be included in the Lump Sum bid for Clearing and Grubbing. All buildings, structures, utilities, and other obstructions indicated on the plans to remain, must be carefully protected against displacement or damage. Materials and labor for this protection must be included in the Lump Sum cost of Clearing and Grubbing.

Except as otherwise provided for in these specifications, the work to be performed under this Section must also include the clearing and grubbing necessary for the excavation of detention ponds, borrow pits, and the like, and the clearing and grubbing necessary for the construction of designated haul routes, and including the removal and off-site disposal of all product and debris except that which is to be salvaged or which is required to complete the construction of the project.

Where possible, all trenching or excavation within tree protection zones (TPZ) shall be done by hand or an air spade. After excavation, all tree roots greater than one inch (1”) in diameter must be cleanly pruned or saw cut, not crushed or torn. Where it is not possible to hand trench, mechanical excavation may be approved by the Engineer. Trunk/root flare and soil/root protection measures in accordance with Pinellas County Standard Detail Index 1111 must be employed to prevent tree damage from mechanical excavation equipment. The Contractor must not cut tree roots greater than three inches (3”) in diameter within the critical root zone (CRZ) without prior approval of the Engineer, after the inspection of an International Society of Arborists (ISA) Certified Arborist, preferably ISA Tree Risk Assessment Qualified (TRAQ). All root pruning must conform to ANSI A300 (Part 8) Standard Practices (Root Management). After root pruning, cut roots should be covered and kept moist until final grade is established. Cutting tree roots greater than 3” in diameter in the critical root zone (CRZ) or tree roots greater than six inches (6”) in diameter within the TPZ shall be reviewed by a County Arborist to determine if a tree designated to remain may need to be removed to prevent future liability.

The Contractor must make his own inspection to determine the character, density and extent of trees, vegetation, and other items subject to removal and disposal under these provisions. The attention of the Contractor is directed to the fact that the burning of debris resulting from clearing and grubbing operations will not be permitted within County-owned lands or rights-of-way. Nothing in these provisions must be construed to authorize the removal or disturbance of any tree or other form of vegetation, or any marine, land or air creatures’ natural habitat, which may be subject to the jurisdiction of regulatory agencies. This Section must also include the cost for trimming of trees and disposal of the trimmings, as shown on the plans and/or required for construction of project. All tree trimming must be performed by or under the supervision of an ISA Certified Arborist and conform to ANSI A300 (Part 1) Standard Practices (Pruning), cost of which is included in the Clearing and Grubbing pay item.

This Section must also include the temporary relocation of mailboxes during construction and permanent relocation after construction has been completed. The work must also include the relocation of the mailbox foundation. The Contractor must coordinate with the Post Office to confirm the mailbox locations. Mailboxes must be restored to equal or better condition that existed prior to the commencement of construction activities, location of which must meet roadway clear zone requirements found in the FDOT Florida Green Book. Work related to mailboxes must be included in the Lump Sum pay item for Clearing and Grubbing A. Ownership of Removals:

i. All removed materials not claimed by the County must become the property of the Contractor and must be disposed of by the Contractor in areas provided by the Contractor. This work must be included in the pay item Clearing and Grubbing.

ii. Transporting and placement of removed material must be paid for under and included in the pay item of Clearing and Grubbing.

B. Items in County Right-of-Way:

The Contractor must notify in writing all property owners to remove any items (landscaping, signs, irrigation systems, lighting, etc.) from the County Right-of-Way that owners wish to salvage a minimum of fourteen (14) calendar days in advance of construction activities. After the notification period, it is the Contractor’s responsibility to remove said items that conflict with construction activities prior to construction. For irrigation systems that the owners wish to salvage, the contractor must place a temporary cap on the pipe that feeds into the irrigation system conflicting with construction activities within County Right of Way. The price and payment for capping and removal of irrigation systems, and removal of other items must be included in the payment item of Clearing and Grubbing.

C. Irrigation/Sprinkler Systems: The Contractor must restore irrigation systems in the public Right-of-Way to pre-construction conditions (or better). The Contractor must verify the proper working order of sprinkler systems affected by Construction, both prior to and after construction. Restoration and verification efforts must be included in the lump sum cost of Clearing and Grubbing, unless otherwise specified in separate pay items.

D. Tree Protection: Trees not within the Clearing and Grubbing area and those specified to remain within County property/right of way, must be protected during construction with Tree Protection Barricades, in accordance with Pinellas County Standard Detail Index 1111. The payment for Tree Protection must be included in the Lump Sum pay item, “Clearing and Grubbing”.

E. Tree and Stump Removal: Unless otherwise indicated by the Engineer in the construction documents, all trees deemed in conflict with the construction activities must be marked by the Contractor for removal, and field validated by the Engineer and a County Arborist in advance of construction. The Contractor must not remove any trees without authorization from the Engineer, after inspection by an ISA Certified Arborist.

F. This work must be included and paid for under the pay item Clearing and Grubbing. Tree stumps, roots, debris, subterranean items, and other abandoned items:

i. Unless otherwise directed by the Engineer, must be removed from sidewalk, drainage, roadway and driveway areas to a depth of 1) six (6) inches below the bottom of the aforementioned item OR 2) four (4) feet below the proposed surface (the greater of the two) and backfilled with A-1 or A-3 soil material. The excavation and backfilling must be included in the Lump Sum cost of Clearing and Grubbing.

Basis of Payment The work and incidental costs specified as being covered under this Section must be paid for at the contract unit price per Lump Sum (LS), for Clearing and Grubbing. If the Schedule of Values includes a specific pay item from the list provided in Section 110, then the work must be paid for at the contract unit price.

If a pay item is not provided in the bid sheets from Section 110, then the cost for said item/work must be included in the “Clearing and Grubbing” (Lump Sum) pay item.

Section 900-0100 of the Pinellas County Roadway Std. Tech. Specs. SIGN -

PROJECT IDENTIFICATION

PAY ITEM NO. 900-0100 SIGNS, PROJECT IDENTIFICATION, Install and Maintain

The work specified under this Section consists of the furnishing of all labor and equipment required for the installation and maintenance of one 4 foot x 8 foot x 1/8 inch aluminum Project Identification Sign (SWFWMD grant requirement) and one 24 inch x 30 inch aluminum Penny for Pinellas sign, during construction, at locations to be designated by the Engineer.

The signs will be provided by the County. At substantial completion of the construction period, the Contractor shall remove and dispose of both signs.

Measurement and Payment: The work specified under this Section shall be paid for Lump Sum (LS) as constructed and accepted.

SPECIAL PROVISIONS

(Amends the Pinellas County Standard Technical Specifications for

Roadway and General Construction) http://www.pinellascounty.org/technical/pdf/roadway-tech-specs-July-2019.pdf

Section 005-0700 of the Pinellas County Roadway Std. Tech. Specs. Survey and Layout The specification for Survey, Construction Layout shall be amended to include:

• The right of way shall be staked out with a stake or marker every 100 feet on all sides of the project boundaries.

• All property corners and section corners shall be protected through the contract period by the contractor, if a property corner is damaged, they will be restored by a Florida registered Professional Land Surveyor at no additional cost to the County.

PAY ITEM NO. 005-0700, Survey and Layout the work specified under this Section must be one Lump Sum (LS) quantity.

Section 005-0850 of the Pinellas County Roadway Std. Tech. Specs. Permitting As-Built Survey Requirements by Contractor The specification for Survey, Permitting As-Built Survey Requirements by Contractor shall be amended to include:

The items requiring as-built surveying include the specific as-built requirements for the Florida Department of Environmental Protection (FDEP) permit and the Southwest Florida Water Management District (SWFWMD) permit. Draft as-builts shall be provided at or prior to substantial completion for review by the Engineer and to allow for corrections (both in the field and in the survey). The following information shall be shown on the as-built survey:

• Benchmark(s) - location and description

• Datum- All elevations should be referenced to a vertical datum clearly identified on the survey

• Drainage structures - locations, dimensions, elevations, pipe sizes and material, inverts

• System grading - dimensions, elevations, contours, final grades

• Detailed finished structure as-built information for the weir including sheet pile top, slot, concrete pad, skimmer, and rip-rap grade. This will include detailed topography minimum 25’ upstream and downstream and across the width of the weir. Grading shots shall include the final grading of the lateral ditch and pipe end finish from the offsite stormwater pond outfall.

• Cross-sections of Pond M10 and 6C areas at maximum 50’ intervals, inclusive of areas between (stations 13+50 to 17+00). The cross sections shall extend from property line to property line and shall show all break points.

• Provide elevations and dimensions of all structures including Pond 6C overflow spillway, control structure S-619C (including elevations and dimensions of structure, weir, concrete pad and grading around structure), and MES’s S-619C2 and S-619D.

• Slurry wall dimensions including top and bottom elevations along length and width.

Measurements to be collected prior to final cover.

As-builts information shall be provided at substantial completion of the project.

PAY ITEM NO. 005-0850, SURVEY, Permitting As-built Requirements the work specified under this Section must be one Lump Sum (LS) quantity.

Section 120-1100 of the Pinellas County Roadway Std. Tech. Specs. Grading The specification for Grading shall be amended to include:

PAY ITEM NO. 120-1100 Grading

The work shall consist of all labor and material required to grade and construct the pond sites, weir, and project area, including suitable and unsuitable soils, and will be paid for under 120-1100, Grading as shown on the Plans and as listed in the specifications.

PAY ITEM NO. 120-1100 Grading the work specified under this Section must be one Lump Sum (LS) quantity.

PAY ITEM NO. 120-1200 REMOVAL OF PROPOSED WEIR SITE SOILS, Soil hauled to landfill by Contractor, including tipping fee

The work specified under this Section shall consist of excavating, stockpiling, loading, and transporting soils from the proposed weir location to the Pinellas County Solid Waste facility for disposal. This work shall include the excavation, loading, transporting, and disposal of unsuitable materials. This work shall include SW-846 Test Method 9095B: Paint Filter Liquids tests on stockpiled soils. The Contractor shall demonstrate that all soils have passed the SW-846 Test Method 9095B: Paint Filter Liquids Test. This work shall include a $51 per ton landfill tipping fee.

The Contractor shall notify the Pinellas County Solid Waste Environmental Specialist at 727-464-7728, 72 hours prior to delivery of soils that will be disposed.

PAY ITEM NO. 120-1200 REMOVAL OF PROPOSED WEIR SITE SOILS, Soil hauled to landfill by Contractor, including tipping fee the work specified in this section shall be paid for per Ton (TN) quantity.

PAY ITEM NO. 120-1210 EXCAVATION, Pond M10 and 6C

The work specified under this Section shall consist of excavating, loading, stockpiling, and hauling soils from the proposed Pond M10 and 6C locations. This work shall include the excavation, loading, transporting, and disposal of excavated materials. Contractor shall take ownership of the soils. The beneficial reuse options of the soil are shown in Appendix 6 - Geosyntec Supplemental Soil Sampling Results Summary dated March 18, 2024.

PAY ITEM NO. 120-1210 EXCAVATION, Pond M10 and 6C the work specified in this section shall be paid for per Cubic Yard (CY) measured in place. The measurement of the excavation shall be paid for under Pay Item No. 005-0703 Earthwork Quantity Measurements.

Section 125-3000 of the Pinellas County Roadway Std. Tech. Specs. Bedding Material The specification for Bedding Material shall be amended to include:

PAY ITEM NO. 125-3058 Bedding Material, Crushed Stone, Size #57, Including Geo-textile Wrap

• The work shall consist of all labor and material required to construct the bedding material with associated geotextile fabric as shown on the Plans.

PAY ITEM NO. 125-3058 Bedding Material, Crushed Stone, Size #57, Including Geo-textile Wrap the work specified under this Section must be paid for per Each (EA) per the plans, satisfactorily completed and accepted and/or adjusted.

Section 162 of the Pinellas County Roadway Std. Tech. Specs. Organic Topsoil Layer The specification for Organic Topsoil Layer shall be amended to include:

PAY ITEM NO. 162-1000, ORGANIC TOPSOIL LAYER, 8”

• The work shall consist of all labor and material required to construct the organic topsoil layer to an 8” thickness.

• Construct the surface to conform to the plan lines and elevations upon completion of the prepared soil operations. Leave the surface of the earthwork in a roughened and loose condition. Remove and replace all materials which fail to meet the required soil classification after placement, and correct any slippage of this material at no cost to the County. Spread the appropriate material uniformly over areas.

PAY ITEM NO. 162-1000, ORGANIC SOIL LAYER, 8” the work specified under this Section must be paid for per Square Yard (SY) per the plans, satisfactorily completed and accepted.

Section 425 of the Pinellas County Roadway Std. Tech. Specs. Inlets, Manholes and Junction Boxes The specification for Inlets, Manholes and Junction Boxes shall be amended to include:

PAY ITEM NO. 425-377-0000, INLET, Ditch Bottom, FDOT Type H, Modified, > 10'

• The work shall consist of all labor and material required to construct structure S-619C - INLET, Ditch Bottom, FDOT Type E, S-2, Modified, < 10' including the weir, slots, concrete pad, hole for 4” PVC, and special grading as shown on the Plans and as listed in the specifications.

PAY ITEM NO. 425-377-0000, INLET, Ditch Bottom, FDOT Type H, Modified, > 10' the work specified under this Section must be one Lump Sum (LS) quantity.

Section 430 of the Pinellas County Roadway Std. Tech. Specs. U-TYPE ENDWALLS AND

FLARED OR MITERED END SECTIONS

The specification for U-TYPE ENDWALLS AND FLARED OR MITERED END SECTIONS shall be amended to include:

PAY ITEM NO. 430-425-4368-2, END SECTION, MITERED, Cross Drain, 43" x 68" ERCP, slope 1:2

• The work shall consist of all labor and material required to construct END SECTION, MITERED, Cross Drain, 43" x 68" ERCP, per index 430-021, slope 1:2 including the special 24” footing and grading as shown on the Plans and as listed in the specifications.

PAY ITEM NO. 430-425-4368-2, END SECTION, MITERED, Cross Drain, 43" x 68" ERCP, slope 1:2 the work specified under this Section must be paid for per Each (EA) of the structures identified in the applicable pay items, satisfactorily completed and accepted.

PAY ITEM NO. 430-425-4368-4, END SECTION, MITERED, Cross Drain, 43" x 68" ERCP, index 430-021, slope 1:4

• The work shall consist of all labor and material required to construct END SECTION, MITERED, Cross Drain, 43" x 68" ERCP, index 430-021, slope 1:4 including grading as shown on the Plans and as listed in the specifications.

PAY ITEM NO. 430-425-4368-4, END SECTION, MITERED, Cross Drain, 43" x 68" ERCP, index 430-021, slope 1:4 the work specified under this Section must be paid for per Each (EA) of the structures identified in the applicable pay items, satisfactorily completed and accepted.

Section 530-2000 of the Pinellas County Roadway Std. Tech. Specs. RIPRAP The specification for RIPRAP shall be amended to include:

PAY ITEM NO. 530-2000 RIPRAP, Rubble w/ Filter Fabric

• The work shall consist of all labor and material required to install the RipRap Rubble with Filter Fabric listed in the plans and specifications.

PAY ITEM NO. 530-2000 RIPRAP, Rubble w/ Filter Fabric the work specified under this Section must be paid for per Ton (TN) installed and accepted.

SUPPLEMENTAL SPECIFICATIONS

ROADWAY / DRAINAGE

(The following supplemental specifications are in addition to the Pinellas County Standard Technical Specifications for Roadway and General Construction)

ITEM NO. 102-1099 VARIABLE MESSAGE BOARD

Description: The work specified under this Section shall meet FDOT requirements and shall consist of Contractor providing two variable message boards (VMBs) to provide advance notice of construction in the project area. VMBs to be placed at 126th Avenue at the location of the weir construction and on 126th Avenue at the Tall Pines Drive intersection. VMBs shall be placed 21 days in advance of construction mobilization.

Measurement and Payment: The work specified in this section shall be paid per each day (ED) quantity.

ITEM NO. 120-0810 DEWATERING

Description: The work specified under this Section shall consist of all labor, equipment and materials associated with dewatering the weir, M10 pond, and 6C pond construction areas, including well point systems, pumping out the work area, and other methods to keep the work area dry. Work shall also include obtaining a Florida Department of Environmental Protection (FDEP) Construction Generic Permit (CGP), and meeting all requirements of said permit, including dewatering, sediment control of the discharged water, turbidity monitoring, and reporting.

Contractor shall submit a dewatering plan (shop drawing) to the COUNTY for review prior to mobilization to the site.

If turbidity exceedances are found to be 29 NTU over background in the dewatering effluent, the CONTRACTOR will be required to:

1. Immediately notify the COUNTY and report the exceedances.

2. Meet with the County and FDEP to resolve the exceedances.

Measurement and Payment: The work specified in this Section shall be paid for at one Lump Sum (LS) quantity, provided and accepted.

ITEM NO. 102-5000 Water for Dust Control

Description: The work specified under this Section consists of the furnishing and application of Water on the construction area including but not limited to sub-grade, un-surfaced base, or other un-surfaced traveled ways, or areas of cleared vegetation, in order to control dust resulting from construction operations. The locations and frequency of application must be as directed by the Engineer.

Water used for controlling moisture content of surfaces to meet compaction requirements, mixture and/or working of material, etc. is at the expense of the contractor, included in the work being performed and not paid as “Water for Dust Control”. The water used may be obtained from any approved source that meets Federal, State and local requirements.

Measurement and Payment: The work specified under this Section must be paid for at the contract unit price per Thousand Gallons (THG) of Water for Dust Control.

ITEM NO. 120-2000 SLURRY WALL

Description: The work specified under this Section shall consist of furnishing the necessary labor, materials, tools, equipment, and services necessary to construct a soil-bentonite slurry wall in accordance with these specifications and with the Florida Department of Transportation Specifications for Road and Bridge Construction. Section 120 EXCAVATION AND EMBANKMENT, as amended. The slurry trench shall have essentially vertical walls with vertical and lateral dimensions corresponding to those shown on the plans by the designer. An as-built survey shall be performed at the time of slurry wall installation to confirm slurry wall depth and width prior to final placement of soil-bentonite slurry. The as-built survey shall be paid for under Pay Item 005-850 Permitting As-Built Survey Requirements by Contractor.

The area to be paid for shall be measured from the top of the slurry wall to the bottom of the slurry trench; and from the beginning to end of slurry wall limits, as shown on the Plans. The area of the soil cap shall be included in the calculation of the square feet of slurry wall.

The cost of geotextile fabric and cap material and the required permeability testing are to be included in the Contract Unit Price for slurry wall, square feet. This price shall include full compensation for furnishing all labor, equipment, tools and incidentals necessary to complete the slurry wall.

SUBMITTALS: Submit the following:

• A122-2.1 Manufacturer's product data and specification data sheet.

• A122-2.2 Design mix

MATERIALS:

• A122-3.1 Soil-Bentonite: The slurry trench shall be constructed using a premium grade, high swelling sodium montmorillonite bentonite that meets or exceeds the standards of the American Petroleum Institute (API) as contained in API specifications 13-A (Spec. 13-A), Twelfth Edition, October, 1988, of the specifications for Oil Wells. Each truckload of bentonite shall have a certificate provided by the supplier certifying that the bentonite meets API 13-A specifications.

• A122-3.2 Fluid Materials: Fresh water which has no deleterious interaction with the bentonite shall be used to manufacture the slurry.

MIXTURE/ PLACEMENT: Soil -bentonite backfill mixture shall not shrink, consolidate or otherwise settle more than2-inches beneath the proposed top of the slurry trench during the first 24 hours after filling, or more than 6-inches thereafter. If settlement in excess of the specifications occurs, the contractor shall be required to refill the trench with approved soil-bentonite backfill at no additional cost to the County.

Properties shall be as follows:

a. The in-situ coefficient of permeability of the soil-bentonite backfill shall be no greater than 1 x 10^-6 cm\sec.

b. The soil-bentonite backfill mixture shall have a minimum bentonite content of 3.0 percent by dry weight of soil.

c. The soil used as backfill shall have no less than 10-percent material by dry weight passing the U.S. Standards No. 200 sieve size.

d. The soil-bentonite mixture shall have no less than 13.0 percent by dry weight passing the U.S. Standards No. 200 sieve, no less than 50 percent of the material passing the No. 20 sieve and no particles larger than 3 - inches in diameter.

e. Soil excavated from the trench can be used as backfill provided it is mixed to be homogeneous and meets the specifications. If the excavated soil does not meet the specifications, borrow material shall be added to the excavated soils, thoroughly mixed with the excavated soils to a homogeneous mixture meeting the specifications and used as backfill.

f. Admixtures shall not be used except as approved in writing by the Engineer.

g. Slurry with balls of partially wetted clay will be rejected at the trench.

At 24 hours past completion of the backfill placement, the slurry trench shall be capped before the exposed backfill can dry out. Prior to placing of the cap material, the slurry trench shall be inspected by the Engineer. Cracked or damaged areas of the slurry trench or areas of excessive settlement shall be replaced before placement of the cap material. Upon completion of the slurry trench, unless otherwise specified by the designer, a layer or geotextile fabric followed by 12 -inches of capping material shall be placed above the slurry trench, followed by embankment material to finished grade.

Unless otherwise specified by the designer, the geotextile fabric shall be Type R-1, Index 199.

The capping material shall be select soil material mixed with Type B stabilizing material in sufficient proportions to provide a Limerock Bearing Ratio of at least 40. The material shall be placed in compacted lifts with the upper 12-inches compacted to at least 95% of the AASHTO T-180 maximum dry density.

YIELD QUALITY CONTROL: Provide samples and measurements to the County approved geotechnical service for the following minimum tests.

a. Daily gradation and permeability of the soil-bentonite backfill.

b. Trench depth and trench bottom soil sample every 20-feet of trench length.

c. Bentonite slurry viscosity (Marsh Punnel 1, 500/1 quart, 40 seconds minimum);

soil-bentonite backfill slump (ASTM C 143, between 4 to 6 inches); and bentonite slurry Density (Mud Balance - between 65 to 95 pounds per cubic foot (PCF), at least 15 PCF lighter than soil-bentonite backfill) every two hours.

NOTES:

1. Slurry wall shall be constructed at pond location as identified in the plan set.

2. The bentonite used shall be a premium grade high-swelling, sodium montmorillonite base product. The contractor shall submit the bio-mineralogic information and Atterberg limits (ASTM D-423 and D-424).

3. The soil-bentonite backfill mixture shall have a minimum bentonite content of 3.0 percent by dry weight of soil and as much bentonite as necessary to meet the permeability criterion of less than 1 x 10^-6 cm\sec.

4. Soil excavation from the trench may be used as backfill material when meeting requirements indicated in the project specifications.

5. A minimum of one sample of backfill per day or one sample for each 300-feet of installed slurry wall shall be obtained for laboratory permeability testing by a geotechnical firm approved by the engineer.

6. Payment shall be made per S.F, and be based upon square foot of project vertical area.

Measurement and Payment: The work specified in this section shall be paid for at the contract unit price per Square Foot (SF) of the size constructed in place and accepted.

ITEM NO. 900-2000 Maintenance of Channel Flow

Description: The work consists of all labor and materials required to maintain channel flow during construction including coffer dams, pumping, temporary piping and provisions for overflow conditions including cleanup after overflows occurs. Work shall include all labor and materials required to operate and maintain the system for the entire duration of construction, and related items as detailed on the plans and listed in the specifications.

The County is providing the below peak discharge table for informational purposes only and consideration by the Contractor.

Measurement and Payment: The work specified under this Section shall be paid for at the contract unit price per Lump Sum (LS) constructed, operated, and accepted.

Design Storm

Rainfall Depth (in)

Peak Discharge cfs gpm

M10 Pond/Pond 6C

Location Channel Link

RF0165

Weir

Location

CF0280B

M10 Pond/Pond 6C

Location Channel Link

RF0165

Weir Location

CF0280B

Mean Annual / 24 hour

4.7

77.9

88.5

34,964

39,722

5 Year / 24 hour 6 113.5 128.9 50,942 57,855

10 Year / 24 hour 7.5 140.7 162.3 63,151 72,846

25 Year / 24 hour 9.5 160.5 185.3 72,037 83,169

50 Year / 24 hour 10.6 167.9 189.4 75,359 85,009

100 Year / 24 hour 12.5 177.3 192.9 79,578 86,580

ITEM NO. 120-2000 SLURRY WALL