HomeMy WebLinkAbout20100967.tiff 400 W�m Engl woo Union Avenue
Englewood, CO 80110
Weld County Planning Departme*P3-914-1445(Phone)
WASTE MANAGEMENT GRE ` ( )FFICE 303-914-9937(Fax)
n,Rr .
May 19, 2010 RECEIVED
Mr. Douglas Ikenberry
Solid and Hazardous Waste Program
4300 Cherry Creek Drive South
Denver, CO 80246-1530
Mr. Troy Swain
Weld County Department of Public Health and Environment
1555 N. 17th Avenue
Greeley, CO 80631
Subject: North Weld Landfill (NWLF) Phase 3a Module 1 Cell Construction
Dear Mr. Ikenberry and Mr. Swain
NWLF is planning to construct the referenced disposal cell during the 2010 construction season.
The basic construction elements include cell excavation, construction of a two-foot thick compacted
soil liner, placement of a six-inch thick drainage layer, and construction of a leachate collection
system consisting of a leachate drain line and temporary leachate collection sump. Enclosed for
your information are the following documents:
• Construction Plans for Phase 3a Module 1 —April 1, 2010
• Technical Specifications for Phase 3a Module 1 Liner Construction —April 2010
• North Weld Landfill Liner System Construction Quality Assurance Plan — Revised April 2010
The project is consistent with the approved NWLF Design and Operations Plan, Site Development
Plans, and CQA Plans including any subsequent approved amendments. For constructability, we
made a minor realignment to the boundary between Phase 3a and future Phase 3b while
maintaining conformance with base grade slope/leachate travel time requirements and specified
material thicknesses.
We are currently going through the contractor selection process and mobilization is anticipated to
begin the week of June 7. We currently expect completing the work by September 15. Should you
wish to visit the site during construction, please do not hesitate to contact Bill Hedberg or me.
Sincerely,
On behalf of North Weld Landfill
Tom weitzer, P.E.
Engineering Manager
Enclosures
Cc: Bill Hedberg, NWLF
Kim Ogle, Weld County Planning Department U SR t
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PL-0777
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TECHNICAL
' SPECIFICATIONS
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I PHASE 3a — MODULE 1 LINER CONSTRUCTION
WASTE MANAGEMENT DISPOSAL SERVICES OF
I COLORADO, INC.
NORTH WELD LANDFILL
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' April 2010
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GENERAL TABLE OF CONTENTS
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SPECIFICATIONS PAGE NO.
' SECTION 02222 - GENERAL EXCAVATION, BACKFILL AND STOCKPILING 1
1.01 SUMMARY 1
1.02 DEFINITIONS 1
I2.01 MATERIALS 2
3.01 PREPARATION 2
I 3.02 EXCAVATION 2
3.03 MATERIAL PLACEMENT 3
3.04 FIELD QUALITY CONTROL 4
SECTION 02246- GRANULAR DRAINAGE MATERIAL 1
1.01 DESCRIPTION /
I1.02 PROJECT/SITE CONDITIONS I
2.01 GRANULAR BLANKET MATERIAL 1
I 3.01 FILL USAGE 2
3.02 PREPARATION 2
3.03 FIELD QUALITY CONTROL 2
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SECTION 02247- CLAY LINER I
I 1.01 DEFINITIONS 1
1.02 REFERENCES 1
1.03 QUALITY ASSURANCE 2
1.04 PROJECT/SITE CONDITIONS 2
2.01 ON SITE CLAY 2
3.01 EXAMINATION 2
I 3.02 EQUIPMENT 3
3.03 PREPARATION 3
3.04 EXCAVATION 3
I 3.05 CLAY MATERIAL PLACEMENT 4
3.06 INTERPHASE/INTERMODULE SEPARATION BERM CONSTRUCTION 5
3.07 FIELD QUALITY CONTROL 5
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SECTION 02300-LINER TIE-IN 1
I 1.01 DESCRIPTION 1
2.01 MATERIALS 1
3.01 CONSTRUCTION 1
3.02 FIELD QUALITY CONTROL I
ITable of Contents
Phase 3a—Module 1 Liner Construction North Weld Landfill
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SECTION 02500-LEACHATE COLLECTION SYSTEM 1
1.01 DESCRIPTION 1
2.01 MATERIALS 1
3.01 STAKING 2
3.02 GRADES 2
3.03 BACKFILL 2
3.04 SURVEY CONTROL 2
SECTION 02560- TEMPORARY LEACHATE COLLECTION SUMP 1
1.01 DESCRIPTION I
2.01 MATERIALS I
3.01 PLACEMENT 1
3.02 STAKING 2
3.03 OPENING SUMP 2
3.04 GRADES 2
SECTION 02700-PROTECTIVE LAYER I
1.01 SUMMARY 1
1.02 DEFINITIONS 1
2.01 MATERIALS I
3.01 PREPARATION 1
3.02 MATERIAL PLACEMENT I
3.03 FIELD QUALITY CONTROL 2
SECTION 15077-GEOTEXTILE FABRIC I
1.01 SUMMARY 1
2.01 GEOTEXTILE FABRIC I
3.01 INSTALLATION 1
3.02 FIELD QUALITY CONTROL I
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Table of Contents I
Phase 3a—Module 1 Liner Construction North Weld Landfill
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DIVISION 2
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SITE WORK
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' SECTION 02222 - GENERAL EXCAVATION, BACKFILL AND
STOCKPILING
PART 1 GENERAL
' 1.01 SUMMARY
A. Section Includes:
1. Excavation to achieve design subbase grades.
2. Placement and compaction of general soil fill for sidewall embankments to achieve
design subbase grades.
' 1.02 DEFINITIONS
A. Unsuitable Material:
1 1. Topsoil, peat, organic soils, and materials containing slag, cinders, foundry sand,
debris, and rubble, or soil with less than required bearing capacity as determined by
' CQA CONSULTANT.
B. Classification: Soil excavated to reach the excavation grades as shown on the plans shall
' be incorporated in the project or placed in stockpiles based on the following
classifications:
1. Cohesive Soils Stockpile: Cohesive Soils stockpile shall consist of fine grained
' cohesive soil/claystone excavated from the project boundaries described above.
This soil shall meet the requirements for cohesive soil material. This material
shall be excavated from the overburden cohesive soils.
2. Topsoil Stockpiles: Topsoil stockpiles shall consist of topsoil and vegetation
excavated from the project boundaries described above.
3. Random Fill Stockpile: Random fill stockpile shall consist of soil and bedrock
' excavated from the project boundaries described above. This soil does not meet
the requirements for cohesive soils stockpile.
' 4. Drainage Blanket Material Stockpile: This stockpile shall consist of sand and/or
gravel or other permeable material classified as SW, SP, GW or GP and meets
requirements for drainage blanket materials (Section 02600).
' 5. Granular Material Stockpile: The granular material stockpile shall consist of the
most coarse grained material excavated from overburden sandy soils or sandstone
bedrock below the overburden soil.
' PART 2 PRODUCTS
General Excavation,Backfill and Stockpiling
Phase 3a—Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 02222-1
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2.01 MATERIALS
A. General Soil Fill:
1. Subsoil free of wood, peat, stones larger than 6 inches in any direction, or other
unsuitable materials.
PART 3 EXECUTION
3.01 PREPARATION
A. Proof-roll embankment surface with a smooth drum roller, or other equipment deemed
suitabme by OWNER, to identify areas of soft material. Determination of soft areas will be
based on OWNER'S judgment, but generally detected by soil deflection of greater than 2
inches and accompanied with stress cracks in soil when rolled over by heavy construction
equipment. Remove unsuitable material and replace with general soil fill.
3.02 EXCAVATION
A. Excavate within limits of Project to lines, grades and elevations shown.
B. Segregate excavated materials as either topsoil, granular material, gravelly soils, clayey
soils, random soils or unsuitable materials. Do not mix materials.
C. Transport excavated materials to the project or designated stockpile areas.
D. Dewatering
1. Maintain surface water control and free drainage.
2. Provide surface water pumps, hoses and other necessary equipment and labor to
keep excavation free of standing water.
E. Over-excavate to remove unsuitable material as directed by OWNER.
F. Maintain dust control.
G. OWNER may, at its option, perform excavation with the project boundary using a CAT 627
scraper. OWNER will provide CONTRACTOR load counts of excavation performed by
OWNER's scrapers within the project area. Excavation performed by OWNER at a rate of
17 cubic yards per load will be deducted from the CONTRACTOR's final survey
quantities.
General Excavation,Backfill and Stockpiling
Phase 3a—Module I Liner Construction North Weld Landfill
April 2010 PAGE 02222-2
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' 3.03 MATERIAL PLACEMENT
A. Embankment
' 1. Begin construction of embankment at lowest point of fill below grade and construct in
layers by spreading and leveling material during placement. The area to be filled shall
be free of vegetation, or any other materials or soils considered by the CQA
CONSULTANT to be unsuitable. Spread individual layers to uniform thickness
throughout and approximately parallel with finished grade for full width of
embankment.
2. Place general soil fill materials uniformly in 12-inch loose lifts across full width of
' embankment.
3. Compact general soil fill materials at or above optimum moisture and meet minimum of
95% of standard Proctor across full width of embankment before placing next lift.
4. Maintain lifts to provide positive drainage away from construction.
5. Do not place materials such as stumps, logs, brush or other unsuitable materials in
embankment.
6. Do not block or obstruct roads, streets, or pavements with excavated materials, except
as authorized by OWNER.
7. Schedule Work in coordinated effort with OWNER.
A. Stockpile Construction
1. Any stockpiles constructed shall be located as directed by the Owner. Material
placed in all stockpiles shall be placed in layers not exceeding 12 inches. The
completed stockpile surfaces shall be bladed to prevent ponding of surface water.
' The completed stockpile slopes shall be track walked and no steeper than 3:1
(Horizontal: Vertical) slope.
2. Watering shall be performed during all stockpiling to control dust.
3. No stockpiling shall begin until the Contractor's Surveyor has provided
construction staking for the stockpiles, if required.
General Excavation,Backfill and Stockpiling
Phase 3a—Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 02222-3
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3.04 FIELD QUALITY CONTROL
A. Excavation tolerances for slopes, module base and ditches:
1. Grade: -0.2 to+0.0 foot.
2. Line: ±0.2 foot.
B. Completed excavation grades shall be surveyed by CONTRACTOR and inspected by
OWNER'S representatives prior to fill placement. Any grades exceeding the tolerances
will be reworked and resurveyed at CONTRACTOR'S expense.
C. Completed embankment grades shall be surveyed by CONTRACTOR and inspected by
OWNER'S representatives. Any grades exceeding the tolerances will be reworked and
resurveyed at the CONTRACTOR'S expense.
*** END OF SECTION ***
General Excavation,Backfill and Stockpiling
Phase 3a—Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 02222-4
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' SECTION 02246 - GRANULAR DRAINAGE MATERIAL
' PART 1 GENERAL
1.01 DESCRIPTION
This item shall consist of furnishing, hauling and placing a six (6) inch thick drainage layer on a
prepared subgrade in accordance with these specifications and in conformity with the lines,
grades, thickness and typical cross sections shown on the plans. It is anticipated that the
CONTRACTOR will obtain the granular drainage material from off-site sources as approved by
the CQA CONSULTANT. CONTRACTOR shall submit sieve analyses results for the proposed
1 material to the CQA CONSULTANT prior to procurement. Granular material is currently
stockpiled on-site but its fines content may be too high to meet the permeability requirements
specified for the drainage layer. At its option, the CONTRACTOR may evaluate the stockpiled
' material and consider options such as screening to render it suitable for drainage layer material.
Should CONTRACTOR wish to use the on-site material, CONTRACTOR shall provide as a
separate bid item, a unit cost for using the on-site material. Whether an off-site or on-site source
' is used, all materials are subject to approval by the CQA CONSULTANT who shall determine
the suitability of the material to be placed for the sand drainage layer.
1.02 PROJECT/SITE CONDITIONS
A. Do not block or obstruct roads, streets or pavements except when authorized by OWNER.
' B. Schedule Work in coordinated effort with OWNER and other contractors.
PART 2 PRODUCTS
2.01 GRANULAR BLANKET MATERIAL
A. Clean sands classified according to Unified Soil Classification System as SP.
1. Grain Size: 100% passing 1/2 inch size sieve and less than 5% passing No. 200
' sieve. Material gradation may vary provided that testing confirms the material
meets permeability requirements.
2. Permeability: 0.01 cm/sec or greater.
3. Calcium Carbonate: No more than 15%.
Granular Drainage Material
Phase 3a-Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 02246-1
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PART 3 EXECUTION
3.01 FILL USAGE
A. Granular Blanket Material:
1. A sand layer over the base liner in accordance with plans.
2. No blanket material shall be placed until the top of the clay liner has been inspected
and approved by the OWNER.
3.02 PREPARATION
A Surface Water Control:
1. CONTRACTOR is responsible for surface water control within project limits.
2. Keep construction and excavation areas well drained and minimize surface water
ponding. I
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B. Subsurface dewatering not permitted without OWNER'S written permission.
3.03 FIELD QUALITY CONTROL
A. Granular blanket materials shall have a minimum thickness of 1.0 foot with a tolerance
from the design grade of the top of the drainage layer of:
1. Grade: -0.0 to +0.2 foot.
2. Line: ±0.2 foot.
B. Completed material grades/thicknesses shall be surveyed by CONTRACTOR and inspected
by OWNER. Any grades outside of the tolerance will be reworked and resurveyed at
CONTRACTOR'S expense.
*** END OF SECTION ***
Granular Drainage Material
Phase 3a—Module I Liner Construction North Weld Landfill
April 2010 PAGE 02246-2
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' SECTION 02247 - CLAY LINER
' PART GENERAL
1.01 DEFINITIONS
A. Lift:
1. One layer of clay material placed in loose lift and compacted to thickness specified.
1.02 REFERENCES
A. American Society for testing and Materials (ASTM):
1. ASTM D422-63 - Standard Method for Particle Size Analysis of Soils.
' 2. ASTM D1140-54 - Standard Test Method for Amount of Material in Soils Finer
than No. 200 (75 um) Sieve.
3. ASTM D1557-78 - Standard Test Methods for Moisture Density Relations of Soils
' and Soil Aggregate Mixtures Using 10 lb. (4.54 kg) Rammer and 18 inch (457 mm)
Drop.
4. ASTM D1587-83 - Standard Practice for Thin Walled Tube Sampling of Soils.
5. ASTM D2216-80 - Standard Test Method for Laboratory Determination of Water
(Moisture) Content of Soil Rock, and Soil Aggregate Mixtures.
6. ASTM D2487-85 - Standard Test Method for Classification of Soils for
Engineering Purposes.
7. ASTM D2922-81 - Standard Test Method for Density of Soil and Soil Aggregate in
' Place by Nuclear Methods (Shallow-Depth).
8. ASTM D3017-88 - Standard Test Method for Water Content of Soil and Rock in
Place by Nuclear Methods (shallow-Depth).
' 9. ASTM D4318-84 - Standard Test Method for Liquid Limit, Plastic Limit and
Plasticity Index of Soils.
10. ASTM D5084-90 - Standard Test Method for Measurements of Hydraulic
Conductivity of Saturated Porous Materials Using Flexible Wall Perimeter.
Clay Liner
Phase 3a-Module 1 Liner Construction North Weld Landfill
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1.03 QUALITY ASSURANCE
A. OWNER will perform quality assurance in accordance with the North Weld Landfill Liner
System Quality Assurance Plan(copy provided herein).
1.04 PROJECT/SITE CONDITIONS
A. Do not block or obstruct roads, streets, or pavements with excavated materials, except as
authorized by OWNER.
B. Schedule Work in coordinated effort with OWNER and other CONTRACTORS.
PART 2 PRODUCTS
2.01 ON SITE CLAY
A. Properties:
1. Permeability: 1 x 10-7 cm/sec or less (ASTM D5084).
2. Grain Size: P200 content 50% by weight or greater(ASTM D422). I
3. Liquid Limit: Greater than or equal to 25% (ASTM D4318).
4. Plasticity Index: Greater than or equal to 10% (ASTM D4318).
5. Free of stones and inclusions of other soil types larger than three inches in largest
dimension.
6. Non-organic soil classified as CL or CH by Unified Soil Classification System.
8. Compaction: 95% Standard Proctor dry density or greater(ASTM D698).
9. Moisture content: 0%to 4%above optimum(ASTM D698).
10. Degree of saturation: Greater than or equal to 80% on or above the line of
optimums.
PART 3 EXECUTION
3.01 EXAMINATION
A. Proof roll and examine surfaces to receive fill and subgrades within limits of excavation to
determine existence of soft areas, areas loosened by frost action or softened by flooding,
weather or of unsuitable materials.
Clay Liner
Phase 3a—Module 1 Liner Construction North Weld Landfill
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' 1. Determination of soft areas will be based on OWNER'S judgment, but generally
detected by soil deflection of greater than 2 inches and accompanied with stress
cracks in soil when rolled over by heavy construction equipment.
' 3.02 EQUIPMENT
I A. Caterpillar 825C (Caterpillar 815 on liner sideslopes) or CQA CONSULTANT approved
equivalent tamping foot compactor for liner placement.
Ill B. 36-inch diameter disc or CQA CONSULTANT approved equivalent to properly mix and
break the clay and claystone.
IC. Suitable earth moving and watering equipment.
3.03 PREPARATION
IA. Remove or replace material not meeting Specifications, natural soils or compacted fill
softened by frost, flooding or weather.
IB. Do not excavate within influence zone of existing footings or foundations, or similar
structures such as monitoring wells without prior approval of OWNER.
C. Provide minimum 3-day notice to OWNER before placing clay.
ID. Surface Water Control.
1. CONTRACTOR is responsible for surface water control within construction limits
Ithroughout construction including work by other Contractors.
I2. Keep construction site well drained and minimize surface water ponding.
3. Comply with OWNER'S discharge criteria.
' 3.04 EXCAVATION
A. Excavate to elevations and dimensions necessary to complete construction.
B. Do not over-excavate to remove unsuitable material without OWNER'S approval.
C. Do not excavate for other structures until scheduled for construction.
D. Upon completion of excavation, CONTRACTOR will document grades for OWNER'S
inspection before CONTRACTOR proceeds with further Work. Documentation will be in
accordance with OWNER'S Site Specific Quality Assurance Plan.
IClay Liner
Phase 3a—Module I Liner Construction North Weld Landfill
April 2010 PAGE 02247-3
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E. Protect excavated areas from freezing and water damage.
3.05 CLAY MATERIAL PLACEMENT
A. Do not place clay until subbase is certified by CONTRACTOR's Surveyor and approved by
OWNER.
B. Shape subgrade to provide specified clay thickness smooth and free from loose stones.
C. Placement: Scarify and moisture condition previous surface prior to placement of
succeeding clay lifts.
1. Place in 8 inch loose lifts.
2. Maximum Compacted Lift Thickness: 6 inches but not greater than the depth of the
compactor teeth.
3. Tolerance: Maximum acceptable variation for each lift thickness is 1 inch.
1. Remove all stones and similar material greater than 3 inches in diameter.
D. Compaction:
1. Minimum Compaction: 95% of dry density, ASTM D698 standard Proctor.
2. Maximum Permeability: 1 x 10-7 cm/sec, ASTM D5084 laboratory falling head
permeability test.
3. Compaction Moisture Content: 0 to +4% wet of optimum as determined by ASTM
D698 standard Proctor testing.
4. Degree of Saturation: At least 80% of all measurements to have a degree of
saturation on or wet of the line of optimums (approximated by the degree of
saturation corresponding to the optimum moisture content determined by standard
(ASTM D698)Proctor testing).
E. Material distribution and gradation throughout liner shall be such that material is free from
lenses, pockets, streaks or layers of material differing substantially in texture or gradation
from surrounding material. Prevent sand or other soil types from mixing into clay or
forming seams.
Clay Liner
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April 2010 PAGE 02247-4
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' F. Uniformly distribute moisture and disc each lift of clay material prior to compaction. Wet
clay material that is too dry to permit compaction of liner at proper moisture content. Do
not place clay liner at a moisture content less than optimum as defined by ASTM D698. No
' additional payment will be made for drying or wetting clay liner materials.
G. Place layers of clay to form continuous monolithic material. Condition excessively dry or
wet soil before placement of additional lifts. Knead each lift into previously placed lift with
tamping foot compactor, or similar kneading type compactor.
' H. Construct sidewall liners in lifts parallel to side slope or by other acceptable methods as
approved by OWNER.
CONTRACTOR to protect completed clay liner from cracking resulting from desiccation or
freeze/thaw action. Cracking observed in the liner surface shall be repaired by the
CONTRACTOR at no cost to the OWNER.
' J. Do not place clay that is frozen or when the previous surface is frozen. Do not place clay
when air temperatures are below 32°F, unless CONTRACTOR can demonstrate the fill
material and previous surface temperatures can be kept above freezing.
' K. CONTRACTOR shall place clay to minimize ponding of water on clay liner surface.
3.06 INTERPHASE/INTERMODULE SEPARATION BERM CONSTRUCTION
A. No placement of separation berm shall be made until:
' 1. OWNER has inspected placement of the granular drainage blanket and all necessary
record documentation has been obtained.
' 2. Berm alignment is inspected by OWNER.
B. Clay liner materials shall be used to construct the berms. Geotextile fabric shall be placed
' on the drainage layer prior to placing clay for the berm. Moisture conditioning shall be
performed as necessary. Construction methods shall be similar to those employed for the
clay liner except that the initial lift shall be 12 inches to prevent damage to the underlying
' geotextile and drainage layer.
' 3.07 FIELD QUALITY CONTROL
A. Survey:
' 1. The CONTRACTOR shall employ measures to the satisfaction of the OWNER that
demonstrate each in-place lift is constructed to the specified thickness.
Clay Liner
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2. Finished surface of clay shall have a minimum thickness of 2 feet and top of clay
shall have a tolerance of-0.0 to +0.1 foot of the design grades. Any grades outside
of the tolerance will be reworked and resurveyed at CONTRACTOR'S expense.
B. Testing:
1. Perform soil testing to determine characteristics of base soils prior to construction of
clay liner.
2. Clay testing will be performed throughout Project by OWNER to monitor clay
parameters and assist CONTRACTOR in selection of appropriate material for liner
construction.
3. CONTRACTOR to assist OWNER in obtaining soil samples.
4. Testing frequencies for construction quality assurance are defined in Table 1 of the I
Site Specific Quality Assurance Plan. Test locations shall be selected at random by 1
OWNER'S representatives.
5. Rework lifts that fail to meet field density or moisture testing. Rework includes:
a. Define rework area.
b. Disc.
c. Moisture condition.
d. Compact.
e. Re-test.
Notify OWNER when reworked area is ready for re-test. Prior to discing area to meet
density requirements, CONTRACTOR may consider compacting rework area first.
Reworked areas that fail re-testing shall have lift or material removed and replaced at no
cost to OWNER.
*** END OF SECTION ***
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Clay Liner
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April 2010 PAGE 02247-6
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' SECTION 02300 - LINER TIE-IN
PART 1 GENERAL
' 1.0 DESCRIPTION
' This item shall consist of completing the tie-in of the clay liner(Section 02247), the leachate
collection system (Section 02500) and the drainage layer (Section 02246) between Phase 1
Modules 2 and 3 and Phase 2 Modules 3 and 4. No tie-in work shall occur until the clay liner
and leachate collection system are completed as determined by the OWNER and CQA
CONSULTANT.
PART 2 PRODUCTS
2.01 MATERIALS
A. The materials to be used are those described in Section 02247—Clay Liner, Section
02500—Leachate Collection System and Section 02246 —Granular Drainage Materials
PART 3 EXECUTION
3.01 CONSTRUCTION
' A. Construct tie-in as shown on the Plans.
B. Excavate the compacted module separation berm and compacted soil block as shown on
the Plans between Phase 3a Module 1 and existing Phases 2 and 3.
' C. Following removal of the module separation berm, bench the existing exposed clay liner
and construct clay liner tie-in. CQA CONSULTANT to inspect and approve benching
and clay liner tie-in prior to placement of overlying granular drainage material and
protective cover.
D. Granular drainage material and protective cover shall be placed over the completed clay
liner tie-in as shown on the Plans.
' 3.02 FIELD QUALITY CONTROL
A. CQA CONSULTANT to confirm the Work conforms to installation specifications and
Plans.
' *** END OF SECTION ***
Liner Tie-In
Phase 3a—Module I Liner Construction North Weld Landfill
April 2010 PAGE 02300-1
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SECTION 02500 - LEACHATE COLLECTION SYSTEM
PART 1: GENERAL
1.01 DESCRIPTION:
A. The leachate collection system consists of a gravel drain line composed of gravel drainage
material wrapped in geotextile fabric. This work includes, but is not limited to
procurement, placement of approved gravel drainage and geotextile materials. All work
shall be done in strict accordance with these specifications and in conformance with the
dimensions,typical sections, lines and grades shown on the plans.
B. Section 2560 of these specifications describes the requirement for the temporary leachate
collection sump.
PART 2: PRODUCTS
2.01 MATERIALS:
A. Drainage Gravel Material: Gravel drain lines shall consist of rounded, semiangular or
angular clean gravel or other permeable material.
1. Unified Soil Classification: GP
2. Permeability: Equal to or greater than 1 cm/sec
3. Gradation: Zero to five percent passing the 3/8-inch sieve; have a D50 less than the
1.5-inch sieve; have a minimum of 99% and passing the 3-inch sieve. The material
gradation may vary from the above if testing confirms the material meets permeability
requirements.
4. Free of foreign matter, lumps or excessive amounts of clay and other objectionable or
foreign substances.
B. Geotextile Fabric: The gravel drain lines shall be wrapped in nonwoven geotextile fabric as
per the plans. This fabric shall have a mass per unit area equal to or greater than
10 oz./sq.yd. The OWNER shall provide the geotextile.
Leachate Collection System
Phase 3a—Module I Liner Construction North Weld Landfill
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PART 3: EXECUTION
3.01 STAKING:
' The CONTRACTOR's Surveyor will establish the location of the work by means of the
construction grid provided by OWNER. It shall be the CONTRACTOR's sole responsibility to lay
out the work from plan dimensions and grid, and to transfer elevations from construction stakes as
' necessary.
3.02 GRADES:
A. The low points that form the grade break in the cohesive soil liner along the leachate
collection gravel drain alignment shall be to within -0.00 to +0.10 ft. of the lines and grades
shown on the plans. Any area below grade shall be brought to grade at the
' CONTRACTOR's expense, with cohesive soil layer material. Grades shall be smooth
without humps or sags.
' B. The CQA CONSULTANT shall be notified with reasonable notice in advance when a
section is ready for installation of the leachate collection gravel drainage line. CQA
CONSULTANT at that time will make a determination as to the suitability of the area and
' will give notice to the CONTRACTOR to proceed or repair deficient areas.
3.03 BACKFILL:
' A. Drainage gravel lines shall include the placement of specified materials in the geotextile
fabric. No placement shall commence until the area has been inspected and approved by the
CQA CONSULTANT. The drainage gravel shall be filled to the level of 12 inches above
' the top of the cohesive soil layer, as shown on the drawings or as directed by the CQA
CONSULTANT.
B. The CONTRACTOR shall place the drainage gravel along the drain line in a manner, which
' will not damage the geotextile.
3.04 SURVEY CONTROL:
' The surveyor shall survey the final location and elevation of the leachate collection gravel drain
lines and shall make particular note of ending locations of collection lines to allow for future tie-in
to be performed.
** END OF SECTION **
Leachate Collection System
Phase 3a—Module 1 Liner Construction North Weld Landfill
' April 2010 PAGE 02500-2
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SECTION 02560 - TEMPORARY LEACHATE COLLECTION SUMP
PART 1: GENERAL
1.01 DESCRIPTION:
The leachate collection sump consists of excavation, furnishing, hauling and placement of bedding,
vertical riser pipe, geotextile fabric, and removal or disposal of materials as necessary. This work
includes, but is not limited to, excavation to design grades and placement of approved bedding or
backfill materials. All work shall be done in accordance with these specifications or as shown on
the drawings.
PART 2: PRODUCTS
2.01 MATERIALS:
A. Liner per Section 02247—Clay Liner
B. 18-inch diameter HANCOR Landfill Grade or equivalent riser pipe including end cap
placed on a 3' x 3' x 1" HDPE sheet. The lower 5 feet of the riser pipe shall be
perforated (5/8" diameter perforations) and the upper 7 feet of the riser pipe shall be solid
wall with a removal end cap. Alternative perforations may be considered provided the
open area per lineal foot of pipe does not decrease.
C. Geotextile per Section 15077—Geotextile Fabric. Geotextile to be provided by OWNER.
D. Rock backfill — Gradation: 1-1/2 to 3 inch (in longest dimension) rounded, semi-angular
to angular gravel with less than 5% fines (minus the No. 200 sieve). The
CONTRACTOR shall submit sieve analysis and laboratory test results for the proposed
rock backfill for approval by the CQA CONSULTANT prior to procurement.
PART 3: EXECUTION
3.01 PLACEMENT:
Liner construction: Construct per Section 02247—Clay Liner
Riser Pipe: Install 18-inch vertical riser pipe as shown on Plans
Geotextile Fabric: Install per Section 15077—Geotextile Fabric.
Rock Backfill: Rock backfill shall be placed carefully around the riser pipe such that it is not
unequally loaded or displaced during backfill placement.
Temporary Leachate Collection Sump I
Phase 3a—Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 02560-1
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3.02 STAKING:
' A. No excavation shall be made until the CONTRACTOR's Surveyor has set stakes outlining
the installation.
B. The CONTRACTOR's Surveyor will establish the location of the work by means of offset
stakes, if applicable, and will indicate the depth of cut when required. It shall be the
' CONTRACTOR's sole responsibility to lay out the work from plan dimensions or offset
stakes and to transfer elevations from construction stakes as necessary.
3.03 OPENING SUMP:
The sump shall be opened in accordance with the lines and grades given for the work, at such times
and as far in advance of the work as may be required by the OWNER.
' 3.04 GRADES:
A. The bottom of the sump (top of cohesive soil layer) shall be excavated to within-0.0 to+0.1
ft. at the lines and grades shown on the plans. Any portion of the sump excavated below
grade shall be returned to grade at the CONTRACTOR's expense, with clay liner material.
Grades shall be smooth without humps or sags.
' B. The CQA CONSULTANT shall be notified with reasonable notice in advance when the
sump has been excavated and is ready for placement of the geotextile filter fabric. The
' CQA CONSULTANT at that time will make a determination as to the suitability of the
excavation and will give notice to the CONTRACTOR to proceed or remove additional
material.
** END OF SECTION **
Temporary Leachate Collection Sump
Phase 3a—Module 1 Liner Construction North Weld Landfill
' April 2010 PAGE 02560-1
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SECTION 02700-PROTECTIVE LAYER
PART 1 GENERAL
1.01 SUMMARY
A. Section includes:
1. Hauling and placement of protective layer soil above the clay liner on the side 1
slopes to achieve design grades.
1.02 DEFINITIONS
A. Unsuitable Material:
1. Topsoil, peat, organic soils, and materials containing slag, cinders, foundry sand,
debris, and rubble, or soil with less than required bearing capacity as determined by
ENGINEER.
PART 2 PRODUCTS
2.01 MATERIALS
A. Protective Layer Soil:
1. Stockpiled materials as described in Section 02200 and approved by ENGINEER.
CQA CONSULTANT will designate which stockpiles will be used for the
protective layer soil.
PART 3 EXECUTION
3.01 PREPARATION
A. The protective layer shall be placed where designated on the plans or as directed by the
CQA CONSULTANT.
3.02 MATERIAL PLACEMENT
A. The method of placement of the protective layer shall not cause rutting or any decrease of
thickness of the clay liner. The CQA CONSULTANT prior to commencing the work shall
approve all placement procedures.
B. The protective layer shall be formed of satisfactory materials with a lifts thickness of not
less than six (6) inches in loose depth.
C. The grading operations shall be conducted, and the soil strata placed to produce a soil
structure as shown on the typical cross section or as otherwise specified. All material
Protective Layer
Phase 3a—Module 1 Liner Construction North Weld Landfill
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' shall be free of organic matter such as leaves, grass, roots and other objectionable
material.
' D. Operations on earthwork shall be suspended at any time when satisfactory results cannot
be obtained because of rain, freezing weather, or other unsatisfactory conditions of the
field.
' E. Schedule Work in coordinated effort with OWNER. Do not block or obstruct roads, streets,
or pavements with excavated materials, except as authorized by OWNER.
3.03 FIELD QUALITY CONTROL
A. Tolerances for protective layer soil:
1. Grade: -0.0 to+0.2 foot.
2. Line: ±0.2 foot.
' B. Completed grades shall be surveyed by CONTRACTOR and inspected by OWNER'S
representatives prior to acceptance. Any grades exceeding the tolerances will be reworked
and resurveyed at CONTRACTOR'S expense.
' *** END OF SECTION ***
Protective Layer
Phase 3a—Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 02700-1
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SECTION 15077 - GEOTEXTILE FABRIC
PART 1 GENERAL
' 1.01 SUMMARY
A. This item pertains to geotextile fabric used to enclose the leachate collection gravel drain
' line and in the interphase/module separation berms and temporary leachate sump.
B. Payment: Work specified in this section is considered incidental and cost shall be
included as part of appropriate unit prices specified in bid form.
PART 2 PRODUCTS
2.01 GEOTEXTILE FABRIC
A. OWNER will provide geotextile fabric for the module separation berms.
' PART 3 EXECUTION
3.01 INSTALLATION
A. Install material as shown on the Plans and in accordance with manufacturer's written
instructions.
B. Surface on which fabric is to be placed shall be smooth with no sharp projections.
' C. Fabric to be placed as smooth and wrinkle free as practical without "stretching".
' D. All laps shall be at least 24 inches in width and secured until backfill is placed.
E. Prior to covering, the fabric shall be inspected and approved by CQA CONSULTANT.
E. The geotextile shall be free of tears, holes, other visible damage or wrinkles.
' F. CONTRACTOR shall replace any sections of fabric that are ripped or torn during the
CONTRACTOR's placement of fabric and subsequent materials. Repairs shall be made
to the satisfaction of the CQA CONSULTANT.
' 3.02 FIELD QUALITY CONTROL
A. CQA CONSULTANT to confirm installation and necessary repairs comply with
installation specifications and Plans.
*** END OF SECTION ***
' Geotextile Fabric
Phase 3a—Module 1 Liner Construction North Weld Landfill
April 2010 PAGE 15077-1
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1 LINER SYSTEM CONSTRUCTION
I QUALITY ASSURANCE PLAN
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Revised April 2010
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I TABLE OF CONTENTS
' 1.0 INTRODUCTION 1
1.1 Project Background 1
I1.2 Purpose and Scope 1
1.3 Construction Schedule 1
2.0 PROJECT PERSONNEL AND CONTACTS 1
2.1 Director of Landfill Operations (Project Sponsor) 1
I2.2 District Manager 2
2.3 Project Manager 2
2.4 Certifying Design Engineer 2
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2.5 Certifying CQA Engineer/CQA Consultant 2
2.6 Site Surveyor 2
2.7 Colorado Department of Public Health and Environment 2
I 2.8 Weld County Department of Public Health and Environment 3
2.9 General Contractor(Owner/Superintendent) 3
2.10 Soils Quality Assurance Laboratory 3
' 3.0 CONSTRUCTION MEETINGS 3
1 3.1 Preconstruction Meeting 3
3.2 Project Progress Meetings 3
' 4.0 DOCUMENTATION 3
4.1 Standard Reporting Procedures 3
4.2 Applicable Forms 4
4.3 Colorado Department of Public Health and Environment Notification 4
4.4 Issue Identification and Corrective Action 4
1 4.5. Photographic Documentation 5
4.6 Site Survey Requirements 5
1 5.0 LANDFILL CONSTRUCTION CONTROL- EARTHWORK 7
5.1 Construction Quality Assurance for Subbase 7
I 5.1.1 Subbase Preparation 7
5.1.2 Leachate Collection Drain Line 7
5.2 Construction Quality Assurance for Cohesive Soil Liner 7
I 5.2.1 Construction Requirements 7
5.2.2 CQA Testing 8
5.2.3 CQA Sampling 8
I 5.2.4 CQA for the Protective Layer 9
5.2.5 CQA for the Module Separation Berms 9
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IRevision 5—April 2010 i
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6.0 CONSTRUCTION CONTROL-LEACHATE COLLECTION DRAIN LINE 9
6.1 Construction Quality Assurance for Leachate Collection System 9
6.1.1 Leachate Collection Drain Line Construction 9
6.1.2 Geotextile Fabric 10
6.1.3 Leachate Collection Drain Gravel 10
6.1.4 Granular Blanket QA Sampling 10
6.1.5 Granular Blanket Documentation 11
6.1.6 Permanent and Temporary Leachate Collection Sumps 11
7.0 FINAL CONSTRUCTION DOCUMENTATION REPORT 11
TABLE 1 Construction Quality Assurance Testing and Frequencies
APPENDIX A Typical Table of Contents
Revision 5—April 2010 ii
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I NORTH WELD LANDFILL
CONSTRUCTION QUALITY ASSURANCE PLAN
' REVISION LOG
IDATE DESCRIPTION OF REVISION BY
12/10/04 Revise Tie-in Language on Page 11 MEM
I04/29/05 Revise survey requirements in Section 4.6 MEM
12/14/07 Updated to include 60-mil HDPE liner at permanent sumps, decreased the MEM
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tolerance for survey lines from ±0.5 foot to +0.2 foot, added record
survey control for protective layer
03/07/08 Incorporated CDPHE comments from letter dated February 15, 2008. LRC
I04/16/10 Miscellaneous edits TSS
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' Revision 5—April 2010 iii
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1 1.0 INTRODUCTION
' 1.1 Project Background
The North Weld Landfill (NWLF), which is owned and operated by Waste Management
Disposal Services of Colorado, Inc., is located in Weld County, Colorado. NWLF is a
170-acre facility, which was originally approved June 27, 1990. The site first received waste
on February 3, 1992.
This Construction Quality Assurance Plan (CQAP) outlines the documentation activities for
the remainder of liner construction in Phase 2 and Phases 3a and 3b. Previous CQAPs have
been prepared separately for Modules 1-5 of Phase 1 and Module 1 of Phase 2.
' This CQAP applies to all liner development within the phases described above and is
intended to eliminate preparation of separate CQAPs for each liner project. The activities
outlined in this CQAP will serve as the basis for the preparation of construction observation
' reports documenting work performed for each of the remaining liner projects in Phases 2, 3a,
and 3b.
1.2 Purpose and Scope
The construction activities associated with each liner project at NWLF include:
• Excavation and stockpiling of soil from within the project area including
appropriate drainage control and stormwater areas;
• Installation of a 2-foot thick cohesive soil liner;
• Installation of a leachate collection system;
' • Installation of a 6-inch thick sand drainage blanket over the liner base and a
6-inch thick protective layer over the liner sideslopes;
' • Installation of cohesive soil phase separation berms around the base liner.
• Installation of permanent or temporary leachate collection sumps.
' 1.3 Construction Schedule
A Construction Quality Assurance (CQA) staff and construction schedule is to be included
as an appendix to the construction documentation report.
2.0 PROJECT PERSONNEL AND CONTACTS
2.1 Director of Landfill Operations(Project Sponsor)
' Name: Steve Derus
Address: Colorado Landfill Division
5500 South Quebec, St.
Suite 250
Greenwood Village, CO 80111
Phone No.: (303)486-6040
FaxNo.: (303)914-1588
Revision 5—April 2010 1
2.2 District Manager
Name: Bill Hedberg
Address: North Weld Landfill
40,000 Weld County Road 25
Ault, CO 80610-9748
Phone No.: (970) 686-2800
Fax No.: (970) 686-1031
23 Project Manager
Name: Tom Schweitzer
Address: Waste Management of Colorado
2400 W. Union Ave.
Englewood, CO 80110
Phone No.: (303)914-1445
Fax No.: (866) 442-0285
2.4 Certifying Design Engineer
Name: To be determined for each construction project
Address:
Phone No.:
Fax No.:
2.5 Certifying CQA Engineer/CQA Consultant
Name: To be determined for each construction project
Address:
Phone No.:
Fax No.:
2.6 Site Surveyor
Name: To be determined for each construction project
Address:
Phone No.:
Fax No.:
2.7 Colorado Department of Public Health and Environment
Name: Douglas Ikenberry
Address: HMWMD-SWIM-B2
4300 Cherry Creek Drive South
Denver, CO 80246-1530
Phone No.: (303) 692-3389
Fax No.: (303)759-5355
Revision 5—April 2010 2
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1 2.8 Weld County Department of Public Health and Environment
' Name: Troy Swain
Address: 1555 N. 17th Avenue, Greeley, CO 80631
Phone No.: (970) 304-6415
Fax No.: (970) 304-6411
2.9 General Contractor(Owner/Superintendent)
Name: To be determined for each project
Address:
Phone No:
Fax No.:
2.10 Soils Quality Assurance Laboratory
Name: To be determined for each project
Address:
' Phone No.:
Fax No.:
' 3.0 CONSTRUCTION MEETINGS
3.1 Preconstruction Meeting
' Prior to the start of liner construction a meeting shall be held involving the General
Contractor, District Manager, Project Manager, the Site Surveyor and the CQA Consultant.
' The Pre-Construction Meeting Agenda, which identifies parties, documents, lines of
communication and requirements, etc. The minutes of the meeting, shall be included as an
appendix to the construction documentation report.
' 3.2 Project Progress Meetings
Generally, project progress meetings will be conducted on a weekly basis (prior to
completion of the cohesive soil liner) with the General Contractor, CQA Consultant, District
Manager, the Project Manager, and the Site Surveyor (as necessary). These meetings will
include updates to the activity schedule, a summary of work activities, testing results,
' discussion of any necessary decisions regarding construction activities, project requirements
and schedule for the up coming week. If necessary, a brief daily meeting with the above-
parties will be conducted to address any critical construction matters and determine an
acceptable course of action. The CQA Consultant shall maintain a file containing notes from
such meetings and a copy of the notes shall be provided to the Project Manager.
' 4.0 DOCUMENTATION
4.1 Standard Reporting Procedures
' The CQA Consultant shall issue a daily report of construction activities. These reports shall
contain, at a minimum,the following information:
1. Date, project name, location,weather and other information as appropriate.
Revision 5—April 2010 3
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2. Description and locations of on-going construction.
3. Equipment used.
4. Description of areas tested and sampled.
5. Description of areas requiring reconditioning, retesting and procedures followed.
6. Summary of clay moisture at time of placement and lift thickness.
7. Surveys performed for lift thickness control and any record surveys performed
for trench, piping and stone grades.
8. Description of any variations from approved design and justification for the
variance.
4.2 Applicable Forms
The forms to be used in documenting the daily activities consist of the following:
I. Telephone Memorandum
2. Daily Field Report
3. Request for Information
4. Field Density Test Report
5. Soil Sample Test Request Record 11
6. Soil Testing Tracking Log
Prior to the preconstruction meeting, the CQA Consultant shall provide the Project Manager
with samples of these forms for review and approval.
All completed daily report forms shall be bound separate from the CQA report and copies
shall be kept in the NWLF and at the CQA Consultant's files.
4.3 Colorado Department of Public Health and Environment Notification
All contact with the Colorado Department of Public Health and Environment and the Weld
County Department of Public Health and Environment will be the responsibility of and
conducted by the Project Manager or designate.
4.4 Issue Identification and Corrective Action
The CQA Consultant is required to inform the Contractor, in a timely manner, of any
difference between the interpretation of the plans and specifications by the Contractor versus
the CQA Consultant interpretation. hi addition, any actual or suspected work deficiencies
shall be brought to the attention of the Project Manager.
If a difference in interpretation cannot readily be resolved between the General Contractor
and CQA Consultant, a meeting shall be held involving the District Manager, Project
Manager, General Contractor, and CQA Consultant. If the issue involves a possible design
Revision 5—April 2010 4
' modification, the Design Engineer may be contacted. The meeting shall define and discuss
the issue, review alternative solutions, and implement an action plan to resolve the issue to
' the satisfaction of all parties.
If a field modification is required which affects a permit condition or a regulatory
requirement, the Colorado Department of Public Health and Environment and, if necessary,
' the Weld County Planning Department and Weld County Department of Public Health and
Environment shall be contacted to inform them of the design change. The discussion with
the agencies will confirm their concurrence with the need for a field modification and what
documentation they require.
The conversation shall be documented by the Project Manager including completing a field
' modification form and phone memo documenting the discussion and verbal concurrence with
the state and local agencies.
' Applicable forms shall be included in an appendix to the report.
4.5. Photographic Documentation
' Photographs (indicating date of exposure) shall be taken with a date back camera to
document observations, and as-built conditions of all elements of construction. These photos
will be labeled to identify, at a minimum, date, location where photo was taken, direction,
and a brief description of the photo. The photographs will be captioned and compiled in a
photograph album in chronological order by the CQA Consultant. Copies of the album shall
be kept in the NWLF and CQA Consultant's files.
' 4.6 Site Survey Requirements
Site survey requirements include performing record surveys. At a minimum, the record
' survey will be performed on a 50-foot grid pattern on the subbase and base area. The record
survey confirms that the landfill liner was constructed in accordance with the approved
design grades. The record survey to be performed by the Contractor's Surveyor will include:
1. Subgrade record survey
a. Subbase on a 50'x 50' grid. Subsequent floor layers including cohesive soil
liner and drainage layer shall be certified at the same horizontal locations as
the subgrade.
b. All subgrade breaklines, as appropriate, on 50' centers.
c. Edge of the subgrade/cohesive soil liner interface for the existing liner on
' 50' centers.
d. Center line/toes of the perimeter drainage channel on 50' centers.
2. Top of compacted cohesive soil liner and protective layer(i.e. where applicable)
a. 50' x 50' grid. The certification grid shall be the same grid used for the
certification of the subgrade.
b. All breaklines, as appropriate, and edges on 50' centers.
c. Top of edge where liners are tied together on 50' centers.
Revision 5—April 2010 5
d. Certification staking will be performed along mid slope points for the
protective layer on side slopes.
3. Leachate collection drain line and permanent/temporary sump
a. Subbase at 50 ft. intervals along the leachate collection drain line.
b. Top of compacted cohesive soil liner along the leachate collection drain line
at 50 ft. intervals.
c. Survey stationing used for certification of the subgrade and top of cohesive
soil liner and protective layer (i.e. where applicable), shall be at the same
horizontal locations for each layer. Each design point along the
50' stationing will have two or three associated elevations — subgrade and
top of cohesive soil liner and protective layer(i.e. where applicable).
d. The permanent/temporary leachate sump shall have a cross section surveyed
perpendicular to the alignment of the leachate collection drain line.
Each survey location on the cross section shall have a certification for the
subgrade and top of cohesive soil liner.
4. Finished grades
a. Top of drainage layer on 50' grid. This certification shall use the same grid used for the certification of the subgrade and top of cohesive soil liner.
Thickness of the 6-inch drainage layer shall be summarized in a table and
included in the documentation report. Thickness of the drainage layer shall
be verified using a calibrated probe. Depth locations shall be shown on a
plan view drawing and included in the documentation report.
b. All finished breaklines, as appropriate, toes and tops of slopes on 50' centers
The CQA Consultant shall reference all test and sample points and reconstructed areas by
measuring from reference points established for the on-site coordinate system.
All survey data will be reduced at the end of each day and given to the CQA Consultant in
the form of a report. All surveying notes will be recorded in a field book and kept in the
CQA Consultant's field files. The record grade tables to be used in the field and the final
documentation report to document compliance with design criteria shall be included in an
appendix to the report.
Tolerances for excavation and fill areas (at subgrade) shall be as follows:
5. Slopes: Line: ±0.2 foot
Grade: -0.2 to+0.0 feet
6. Module Base: Line: ±0.2 foot
Grade: -0.2 to+0.0 feet
7. Soil liner: The cohesive soil liner shall have a minimum thickness of 2.0 feet
with a tolerance of -0.0 to +0.1 feet of the design grades for the top of the
cohesive soil liner.
Revision 5—April 2010 6
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8. Protective layer: The protective soil layer shall be constructed to a tolerance of
—0.0 to +0.2 feet of the top of design grade for the top of the protective layer as
' shown on the plans. The protective soil layer shall be constructed so that the
combined thickness of the protective layer and clay layer is 2.5 to 2.8 feet
perpendicular to the slopes.
' 9. Sand drainage layer: The granular drainage layer shall have a minimum
thickness of 0.5 feet.
5.0 LANDFILL CONSTRUCTION CONTROL - EARTHWORK
5.1 Construction Quality Assurance for Subbase
' 5.1.1 Subbase Preparation
' Construction Quality Assurance for subbase preparation involves monitoring grade control as
stated in Section 4.6.
In addition, the subbase area is monitored for unstable areas. Unstable areas that are
' excavated and other over-excavated areas may require controlled fill. This fill shall be
placed in compacted lifts not exceeding 12 inches. Field density testing shall be performed
on this fill on a 50-foot grid pattern for each 12 inch lift placed to assure a minimum density
' of 95% of standard Proctor. A representative sample of the subbase fill soils will be used to
determine a standard Proctor value for maximum density and optimum moisture content of
the soils.
' In the event the fill soils change, standard proctor values shall be determined for each soil
type. Clay surface soils along the previous cell shall be removed, providing for a clean
' "key-in"between cells during clay placement.
5.1.2 Leachate Collection Drain Line
While constructing the subbase, the chevron pattern will be graded to form the leachate
collection drain line. The leachate collection drain line is shown on the plans.
As discussed in Section 4.6, the Contractor's Surveyor will perform survey documentation of
the construction of the leachate collection drain line.
' Field density testing and clay sampling for quality assurance will be performed during liner
and drain line construction as discussed in Section 5.2.
5.2 Construction Quality Assurance for Cohesive Soil Liner
5.2.1 Construction Requirements
' The cohesive soil liner shall be constructed in accordance with design criteria of the North
Weld Landfill Design and Operations Plan.
' 1. Base grades shall be consistent with approved design grades. The minimum
leachate collection drain line slope shall be 2%.
2. The minimum thickness of the cohesive soil liner at all locations shall be at least
2 feet measured perpendicular to the liner surface.
Revision 5—April 2010 7
3. The clay-lined base and interior sidewall at all locations shall be constructed in
lift heights no greater than 6 inches after compaction but no greater than the
depth of the compactor teeth.
4. The typical side slopes shall not exceed 3 horizontal to 1 vertical.
The cohesive soil will be placed in approximately 8-inch loose lifts. A 36-inch (minimum)
diameter disc will be used to break up the clay clogs, expose stones in clay to allow for
removal and to assist in raising the moisture content to approximately 0 to 4 percent above
optimum moisture content as determined by Standard Proctor test (ASTM-D698).
Compaction will be performed using a Caterpillar 825 (Caterpillar 815) tamping foot
compactor or equivalent. The number of passes required to achieve the minimum 95 percent
compaction will be determined during the first lift of cohesive soil placement, and monitored
on subsequent lifts.
5.2.2 CQA Testing
Density testing of Cohesive soil liner shall be performed randomly but on a density
equivalent to a 100 foot grid pattern for each 6 inch compacted thickness of liner placed.
For sidewalls, minimum testing requirements are determined based on the surface area of the
sidewalls.
The testing grid pattern shall be offset on each subsequent lift. Additional density tests shall
be obtained in confined areas where equipment movement is hindered or hand compaction is
necessary. The number of density tests shall be recommended by the CQA Consultant based
on the size of the confined area and shall be approved by the Project Manager. If areas are
encountered which do not meet the specified moisture content, percent compaction or
percent saturation, the area will be reworked; moisture conditioned and recompacted as
necessary. Retests will be performed following the rework activities.
Each penetration made into the cohesive soil liner for density testing purposes shall be
repaired after testing. The test hole shall be repaired by backfilling the test hole with
bentonite and hydrated or other material approved by the CQA Consultant.
All density tests will be reported on the field density forms. Test locations will be presented
on the plan view for cohesive soil liner tests and sample locations. Completed field density
forms shall be included in an appendix to the report. Prior to the preconstruction meeting,
the CQA Consultant shall provide the Project Manager with a sample of the field density
form for review and approval.
5.2.3 CQA Sampling
The material used to construct this liner shall conform to the following specifications:
Classification: CL or CH under the Unified Soil Classification System
Permeability: Less than or equal to lx 1W7 cm/sec or less
Density: Greater than or equal to 95% (ASTM D 698)
Liquid Limit: Greater than 25 percent
Plasticity Index: Greater than 10 percent
Saturation (%) Greater than or equal to 80%
Grain Size P200 content of 50% or greater by weight
Revision 5—April 2010 8
Cohesive soil samples shall be obtained during liner construction for the following tests:
t 1. Grain Size ASTM D422/1140 (excludes hydrometer)
2. Atterberg Limits ASTM D4318
' 3. Moisture Content ASTM D2216
4. Standard Proctor ASTM D698
5. Permeability ASTM D5084
The ASTM designations and sampling frequencies for the above tests are shown on Table 1.
Note: Each shelby tube sample must have a minimum length of 4 inches. Each void
remaining after extracting the undisturbed sample will be backfilled with bentonite and
' hydrated. Shelby tube sample locations will be presented on the plan view.
A soil sample inventory log will be maintained as samples are acquired. Prior to the
preconstruction meeting, the CQA Consultant shall provide the Project Manager with a
sample of this inventory log for review and approval. All completed inventory logs shall be
included in an Appendix to the report.
' 5.2.4 CQA for the Protective Layer
A 6-inch soil protective layer shall be placed over the cohesive soil-lined sideslopes.
' The material shall consist of cohesive soil liner material or random material described in the
Project Technical Specifications. The protective layer shall be placed in successive lifts of
not more than eight inches in loose depth. Compaction operations shall consist of at least
' three passes with suitable equipment or until the CQA Consultant is satisfied with the
compaction. The CQA Consultant shall observe and report on appropriate CQA test results
and observe/report on placement operations to verify uniform lift thickness, proper layer
' bonding, adequate compaction and appropriate moisture conditions.
5.2.5 CQA for the Module Separation Berms
Cohesive soil liner materials shall be used to construct the berms. Moisture conditioning
shall be performed as necessary. Berm material, located above the permanent liner, which
will be removed during future construction will not be subjected to permeability testing.
' 6.0 CONSTRUCTION CONTROL - LEACHATE COLLECTION DRAIN LINE
' 6.1 Construction Quality Assurance for Leachate Collection System
6.1.1 Leachate Collection Drain Line Construction
When the 2-foot cohesive soil liner is completed the gravel drain line composed of gravel
drainage material wrapped in geotextile fabric will then follow as discussed in this section.
Revision 5—April 2010 9
6.1.2 Geotextile Fabric
The geotextile fabric used to wrap the leachate collection trench shall be 10 oz. non-woven
geotextile. Placement shall be performed as shown on the Plans and shall conform to the
following:
1. Fabric to be placed smooth and wrinkle free as possible without"stretching".
2. The gravel drain lines shall be wrapped in geotextile fabric as per the plans.
3. Fabric shall overlap at all seams by at least 2 ft.
CQA requirements for the fabric are:
1. Fabric shall be free of tears, holes, other visible damage or significant folds or
wrinkles.
2. Geotextile quality control certificates shall be included in an appendix to the
construction documentation report.
6.1.3 Leachate Collection Drain Gravel
The drainage gravel material used in the collection drain shall consist of rounded,
semiangular or angular clean gravel or other permeable material, which meets the following
requirements:
1. The gravel material will be classified according to the Unified Soil Classification
System as GP poorly graded gravel.
2. Zero to five percent passing the 3/8 inch sieve; have a D50 less than 1.5 inch
sieve; have a minimum of 99% passing the 3-inch sieve;
3. Permeability ≥ lcm/sec.
4. The drainage material shall be placed as shown on the plans.
The types of testing, ASTM designations and sampling frequencies for the leachate
collection drain gravel are shown on Table 1.
6.1.4 Granular Blanket QA Sampling
The granular blanket for the North Weld Landfill consists of a minimum of 6 inches of sand
placed over the cohesive soil liner. The drainage blanket requirements are as follows:
1. Grain Size: 95% passing 1/2 inch sieve and less than 5% passing #200 sieve.
(additional specifications are included in the Technical Specifications).
2. Permeability ≥ lx10"2 cm/sec.
The types of testing, ASTM designations and sampling frequencies for the granular blanket
are shown on Table 1. The CQA Consultant will document sample locations.
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1 6.1.5 Granular Blanket Documentation
' The CQA Consultant shall record thickness of the 6-inch thick granular drainage blanket on a
50' grid pattern. Thickness of the drainage layer shall be verified using a calibrated probe.
The sand blanket depth documentation shall be summarized in a table and included in the
' documentation report. Depth check locations shall be shown on a plan view drawing of the
project area and included in the documentation report.
6.1.6 Permanent and Temporary Leachate Collection Sumps
A permanent leachate collection sump will be installed at the low point in each of the four
disposal phases (Phase 1, 2, 3a and 3b) as shown on the approved Site Development Plan
' dated January 12, 1996. A temporary leachate collection sump will be installed at the low
point of each module as shown on appropriate plans. The CQA Consultant shall verify in the
documentation report that the work was performed in accordance with the submitted plans
and specifications. This will include verification that the 60 mil HDPE liner in the
permanent sump has been installed per the specifications and anchored per the drawings. A
minimum of one field moisture/density test will be performed on the compacted clay soil
located in the HDPE anchor trench surrounding the permanent sump. The Certifying CQA
Engineer will ensure that appropriate documentation will be provided in the CQA report
confirming the condition of the cohesive liner surface, the resin used for the HDPE and the
quality of the HDPE liner as it is placed, including whether installation specifications were
met. An as-built drawing of the permanent sump will be submitted in the CQA report and
will include HDPE panel layout and seam, destructive test, and repair locations.
' 7.0 FINAL CONSTRUCTION DOCUMENTATION REPORT
After completion of each liner project a construction documentation/certification report will
be prepared and submitted to the CDPHE and the WCDPHE. The report will consist of a
detailed narrative describing construction of the area in chronological fashion. It will
describe all major aspects of construction including: excavation subbase preparation, liner
placement, leachate collection gravel drain line construction, protective cover placement,
module separation berm placement and granular blanket placement. An analysis and
discussion of all soil testing work performed will be included as well as proctor curve(s) for
the soils being compacted. A cover letter shall be included under the seal of a registered
professional engineer, rendering and opinion as to whether the facility has been constructed
in substantial conformance to the approved plans and specifications. A registered land
surveyor in the State of Colorado shall certify all survey data/documentation included in the
report. A complete set of record drawings will also be submitted along with the report.
A copy of a typical Table of Contents for the construction documentation/certification report
' is included as Appendix A to this CQAP.
The Contractor shall complete the liner tie-in, as appropriate, described in the Technical
Specifications. No tie-in work shall occur until the liner and LCS in the newly constructed
' module are completed in their entirety as determined by the Owner and CQA Consultant.
The CQA Consultant shall document this work in the construction
documentation/certification report.
Revision 5—April 2010 11
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I TABLE 1
North Weld Landfill
IConstruction Quality Assurance
Cohesive Soil Liner& Module Separation Berm Testing and Frequency
Ir )
I Field Density* D2922 1 per 185 cy
(each 100 foot centers per lift)
Field Moisture* D3017 1 per 185 cy
I (each 100 foot centers per lift)
D422/1140
Grain Size (excluding 1 per 3,000 cy 1 per 20,000 cy
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Hydrometer)
Atterberg Limits D4318 l per 3,000 cy 1 per 20,000 cy
Permeability** D5084 1 per 3,000 cy 1 per 20,000 cy
IStandard Proctor D698 1 per 3,000 cy or as material 1 per 20,000 cy
type changes in the field
I One Point Proctor - 1 per day during liner
placement
Moisture Content D2216 1 per 1,000 cy 1 per 20,000 cy
I Note— The degree of saturation for each moisture/density test shall be greater than or equal to 80%. Historical
site data and or hydrometer testing,ASTM D854 will be used for specific gravity determination.
*- A minimum of one field moisture/density test will be performed on the compacted clay soil located in the
HDPE anchor trench surrounding the permanent sump.
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** - Permeability testing is not required for cohesive soil liner material placed in separation berms, which will
be removed during future construction.
Granular Drainage Blanket Testing and Frequency
I `4;41 .4:914:41.1'! � Y in'�'-a #4-44 EJY� n m s¢ v-ra&T' r x
n u 4,. .,..q:;"'.- i ��yt
M W ret "l "3 .r� • "§ g al
4 131, k. ew ra x .�l5rk tl,,,'
ID422/D1140 As necessary if
Grain Size (excluding material type 1 per source
changes in the
I hydrometer)
field
Permeability D2434 1 per 3,000 cy 1 per source
' Leachate Collection Gravel Drain Line Testing and Frequency
Vmmai$ t'w ":1, r� 51 . -.1 !A -: "'} 9{i,ltivai 4n::' as lR''Ii 7:7771:7771 ,7777•r(17 :77:77,7:,i'a 7r77,--,t4'ejir
7-,1.}{);.4 � ; vl 'Y l � " wx5`��.4p.,� 91,''.,:1,, :.: r r+" t kzri¢ 4�.,'
*h. '.C : '54&,1 s T tAi 1 i �`:a , §_d41.;f.�,7ti(: . s x mdn r 1 fell! 112 is
Grain Size C136 1 per 1,000 If or Minimum of I per source
2 Samples
Permeability D2434 1 per 1,000 If or Minimum of 1 per source
2 Samples
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APPENDIX A
' TYPICAL TABLE OF CONTENTS
I for
' CONSTRUCTION OBSERVATION REPORT
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Revision 5—April 2010
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' MIDWAY LANDFILL
MODULE SIX-PHASE I
CONSTRUCTION OBSERVATION REPORT
COHESIVE SOIL LINER AND LEACHATE COLLECTION SYSTEM
' TABLE OF CONTENTS
(Typical)
Section
1.0 INTRODUCTION
1.1 Purpose
1.2 Scope
1.3 Facility/Project History
' 2.0 SUMMARY OF CONSTRUCTION ACTIVITIES
3.0 CONSTRUCTION DOCUMENTATION REQUIREMENTS
' 4.0 CONSTRUCTION DOCUMENTATION
4.1 Excavation
' 4.1.1 Construction Requirements
4.1.2 Construction Activities
4.2 Subbase
4.2.1 Construction Requirements
4.2.2 Construction Activities
4.3 Two Foot Cohesive soil liner
4.3.1 Construction Requirements
' 4.3.2 Construction Activities
4.4 Cohesive soil liner Laboratory Soils Testing
4.4.1 Testing Requirements
4.4.2 Testing Procedures, Intervals, and Results
4.5 Granular(Sand) Blanket
4.5.1 Placement Requirements
4.5.2 Placement Activities
4.5.3 Soils Testing
4.6 Leachate Collection System
' 4.6.1 Installation Requirements
4.6.2 Installation Activities
4.7 Module Separation Berm
4.7.1 Construction Requirements
4.7.2 Construction Activities
5.0 CONCLUSIONS
Revision 5—April 2010
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LIST OF TABLES
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Table
I1 Subbase and Cohesive soil liner Record Survey Table
2 Clay Soil Analysis Summary
I3 Leachate Trench and Piping Grades
I4 Sand Drainage Blanket and Collection Stone Laboratory Analysis Summary
5 Sand Drainage Blanket Depth Survey Data
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IRevision 5—April 2010
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' LIST OF APPENDICES
' Appendix
A CQA Staff and Construction Schedule
' B Preconstruction Meeting Notes
C Density Test, Clay Soil and Granular Blanket/Pipe Bedding Sample Location Plan
Sheets
D Moisture-Density Relationship Data
C-1 Liner Support Soil (if needed)
C-2 Clay Soil
E Density Test Data
D-1 Liner Support Soil (if needed)
D-2 Clay Soil
' F Cohesive soil liner Soil Laboratory Test Data
G Granular Blanket/Collection Stone Laboratory Test Data
F-1 Sand Blanket
F-2 Collection Stone
H Quality Control Certificates
H-I Geotextile Quality Control Certificates
H-2 Geomembrane Quality Control Certificates
H-3 Surveyor's Certificate
I Sump Geomembrane(for permanent leachate collection sump)
' I-1 Geomembrane Field Monitoring Summary
I-2 Certificate of Acceptance of Soil Surface
I-3 Geomembrane Deployment Log
' 1-4 Geomembrane Trial Seam Log
I-5 Geomembrane Seam Log
1-6 Geomembrane Seam Test Log
J Specification/Design Modification Forms
K Record Drawings
Revision 5—April 2010
Construction Plans for
Phase 3a Module - April 1 ,
2010 , are oversized maps
Please see Originals in File
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