Attachment E - Leachate Impoundment CQA Plan.pdf

PITKIN COUNTY SOLID WASTE CENTER

CONSTRUCTION QUALITY ASSURANCE PLAN

PROPOSED LEACHATE IMPOUNDMENT POND

PREPARED FOR

PITKIN COUNTY SOLID WASTE CENTER

APRIL 24, 2025

Weaver Consultants Group

F:\PITKIN COUNTY\2025\IMPOUNDMENT\CQA PLAN\REPORT.DOCX 4/24/2025

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TABLE OF CONTENTS

1 INTRODUCTION

1.1 Purpose

1.2 Scope

2 PERSONNEL QUALIFICATIONS AND RESPONSIBILITIES

2.1 Project Meetings

2.2 Personnel Qualifications and Training

3 EARTHWORKS

3.1 Earthworks

3.2 Anchor Trench

4 GEOSYNTHETICS

4.1 HDPE Geomembrane Liner

4.2 Geocomposite Drainage Layers

5 LEAK DETECTION AND LEACHATE EXTRACTION SYSTEM

5.1 Pre‐Construction

5.2 Construction

5.3 LCS System Equipment and Components

6 DOCUMENTATION

6.1 Daily Reports

6.2 Design Changes and Clarifications

6.3 Final Documentation

6.4 Storage of Records

7 REFERENCES

FIGURES

Figure 1 PCSWC Construction/Quality Assurance Organization

TABLES

Tables 4‐1 Soil Minimum Testing Requirements

Tables 4‐2 Geosynthetic Materials Minimum Testing Requirements

Tables 4‐3 Geosynthetic Materials Minimum Test Values

1 INTRODUCTION

This Proposed Leachate Impoundment Pond Construction Quality Assurance Plan (CQA Plan) for the Pitkin County Solid Waste Center (PCSWC), in Aspen, Colorado, has been prepared to outline minimum standards for construction of the impoundment pond, which will be located to the east of the current scalehouse.

1.1 Purpose

This CQA Plan defines the quality assurance (QA) activities that will accompany construction to document that the impoundment is constructed in accordance with the plans, and the requirements of the Colorado Department of Public Health and Environment (CDPHE) related to documentation.

CDPHE guidance pertaining to installation and verification of the leachate impoundment pond was incorporated into this CQA Plan. This CQA Plan was intended to satisfy the Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division, 6 CCR 1007‐2, Part 1, Regulations Pertaining to Solid Waste Sites and Facilities § 9 Waste Impoundments, 2024.

This CQA Plan was prepared to describe the activities that will be performed during construction to satisfy these objectives. Procedures invoked by the CQA Plan are intended to identify problems that may occur during construction and to document that these problems are corrected, before construction is complete.

1.2 Scope

This CQA Plan establishes general administrative and documentation procedures. With respect to specific inspection and testing activities, this plan addresses only those activities associated with construction of the landfill and its support facilities, including excavation pipe installation construction of structural fill layers construction of anchor trenches and sideslope riser trenches testing and installation of geosynthetics placement of leachate collection layers site grading (e.g., civil survey, layout)

2 PERSONNEL QUALIFICATIONS AND RESPONSIBILITIES

The QA organization chart for PCSWC construction is provided as Figure 1. The roles and responsibilities of the parties involved in constructing the landfill components are as follows:

Owner Pitkin County

Permitting Agency CDPHE

Construction Contractor TBD – Each phase of construction is competitively bid

CQA Engineer Weaver Consultants Group, or other qualified firm

CQA Lab TBD – Third Party CQA Testing Laboratory

CQA Surveyor TBD

2.1 Project Meetings

Project meetings for construction quality assurance (CQA) construction projects shall be held at the discretion of the Owner. The intent of the meetings is to ensure communication between organizations involved in the construction of the PCSWC.

2.2 Personnel Qualifications and Training

The qualifications and training required for CQA personnel are described in the following sections.

2.2.1 CQA Engineer

The CQA Engineer shall be a Professional Engineer registered in the State of Colorado with landfill construction certification experience.

2.2.2 CQA Field Personnel

CQA field personnel will have a high school diploma and at least 1 year of experience conducting CQA monitoring for earthworks and geosynthetics installation, or a Bachelor of Science degree from a 4‐year college or university.

3 EARTHWORKS

The earthwork inspection activities (observations and tests) that will be conducted by the CQA personnel during construction of the landfill and support facilities are described below.

The following subsections address each facility component separately and, if appropriate, are further subdivided into sections on pre‐construction, construction, post‐construction, and testing and observation activities that are unique to each component.

Soil testing requirements are summarized in Tables 4‐1.

Sampling of soil and other materials will be required for testing purposes. Every sample shall be assigned a unique identification number that describes the sample location and type. Sample numbers shall be recorded by CQA personnel.

3.1 Earthworks

3.1.1 Excavation

During excavation, CQA personnel shall generally observe the excavated material and subgrade conditions and shall perform the following activities:

Periodically observe stripping and excavation to document that there are no moisture seeps and that soft, organic, and otherwise undesirable materials are removed.

Coordinate with the CQA surveyor to confirm that the depth and slope of the excavations, sumps, surface water drainage ditches, and other construction components meet design requirements.

Prior to placement of any structural backfill CQA personnel will verify that the subgrade has been prepared in accordance with the requirements of the specifications.

Prior to filling, CQA personnel shall test the subgrade with in‐place density methods, at the frequency specified in Table 4‐1.1. Nuclear density methods may be used (e.g., American Society for Testing and Materials (ASTM) D2922), or as approved by the designer.

3.1.2 Fill

During structural fill, CQA personnel will conduct tests and observations to document that the quality of compacted fill meets project specifications. This will include visual observation, monitoring of lift thickness, review of grain size analysis, determining moisture‐compaction characteristics, and measuring in‐place density and moisture content and other tests. Loose lift thickness shall not exceed 9 inches. Field in‐place density tests shall be conducted at a frequency listed in Tables 4‐1.1. Additional tests may be conducted at the discretion of the CQA Engineer.

Structural fill preparation shall be observed by CQA personnel for compliance with the specifications outlined in Table 4‐1.1. The structural fill shall be compacted to at least 95% of standard Proctor dry density (ASTM D698), and in place density shall be measured at the frequency listed in Table 4‐1.1. Compaction and testing will be required if fill is required to bring the subgrade elevations up to design grades, at the frequency listed in Table 4‐1.1.

CQA personnel will coordinate with the CQA surveyor to verify that final lines and grades conform to design requirements. The survey tolerance for the excavation of the subgrade layer shall be ‐0.2 to 0.0 feet, in relation to the design elevations, and ± 0.2 feet in northing and easting. The survey tolerance for the structural fill layers shall be +0.2 to 0.0 feet, in relation to the design elevations, and ± 0.2 feet in northing and easting. Observations shall be recorded on daily field monitoring report forms, drawings, and test data forms.

3.2 Anchor Trench

3.2.1 Pre‐Construction

There are no pre‐construction requirements for the proposed anchor‐trench backfill materials.

3.2.2 Construction

During placement of backfill in the anchor trenches, CQA personnel shall observe the placement operations on a periodic basis and perform the following:

Visually observe the material for contamination with debris or deleterious material;

Visually observe the material for particle size;

Visually observe that the material is moisture conditioned and compacted, as specified;

Observe the placement of the material to document minimum thickness under equipment, to prevent damage to the underlying materials; and

Visually observe to detect any damage to the underlying liner materials.

Tests shall be conducted in accordance with the methods and procedures specified in Table 4‐1.3.

4 GEOSYNTHETICS

The impoundment pond will utilize geosynthetics as part of the containment system.

Various geosynthetic components will be used as part of the design, as presented below.

The CQA personnel shall review conformance testing on samples of the GCL material, submitted by the GCL installer. These activities are described in the following section.

4.1 HDPE Geomembrane Liner

CQA personnel shall review conformance testing on samples of the high‐density polyethylene (HDPE) geomembrane liner material submitted by the manufacturer. These activities are described in the following sections.

4.1.1 Pre‐Construction

CQA personnel shall review conformance tests on samples of the HDPE liner material, submitted by the geomembrane manufacturer. These activities are discussed in the following subsections. Requirements are listed on Table 4‐2.1.

4.1.2 HDPE Manufacturer

Quality control (QC) requirements for the geomembrane manufacturer initially consist of evaluating the raw polymer materials. The resin supplier shall provide documentation with each shipment or production batch (lot) confirming that the raw materials comply with the manufacturers’ product properties and performance requirements. The manufacturer shall test each lot of resin to verify that the raw material meets or exceeds the specifications.

CQA personnel shall review testing results and other documentation submitted by the geomembrane manufacturer for conformance to the specification requirements.

Submittals from the manufacturer include the following:

The origin (resin supplier’s name, resin production plant), identification (brand name, number), and production date of the resin;

A list of quantities and descriptions of materials, other than the base polymer that comprises the geomembrane;

A copy of the quality control certificates issued by the resin supplier;

Reports on the tests conducted by the manufacturer and the CQA Engineer to confirm that the quality of the resin used to manufacture the geomembrane satisfies the specifications;

A statement that no recycled polymer is added to the resin, or that recycled polymer is clean and does not exceed 2% by weight, and does not include material that has seen previous service life;

A data summary sheet, including properties listed in the specifications, measured using test methods indicated in the specifications, or equivalent;

Reports on the tests, including sampling procedures, conducted by the manufacturer and/or the CQA Engineer to confirm that the geomembrane meets the project specifications; and

A certification that property values provided in the properties sheet are guaranteed by the geomembrane manufacturer.

4.1.3 Receiving Inspection

The CQA personnel shall perform receiving inspection on geomembrane material. CQA personnel shall also confirm that transportation, handling, and storage of geomembrane are performed in accordance with the specifications and manufacturer’s instructions, and shall determine the condition of rolls of geomembrane upon delivery to the site.

4.1.4 Construction

Sheets of geomembrane will be welded together after they are placed in the landfill to form a continuous moisture barrier. CQA personnel shall document that the placement and seaming activities are performed in accordance with the specifications; particularly that required materials, methods, and testing procedures are employed. Seams or repaired areas that do not pass the tests shall be repaired and retested, as described in the specifications, until a passing result is achieved. Requirements for geomembrane installation and testing will be described in detail in the specifications and are summarized in the following subsections.

4.1.4.1 General

Each field panel and field seam shall be given an identification code that is consistent with the proposed sequence of installation. A field panel is defined as the area of geomembrane that is to be cut and seamed in the field by the Installer.

On slopes or grades steeper than 10%, seams shall be oriented down and not across the slope. No horizontal seam shall be less than 5 feet from the top of the slope or other area of potential stress concentration. Seams shall not line up with leachate piping runs. The number of field seams shall be minimized in areas such as corners and odd‐shaped geometric locations. In anchor trenches, the geomembrane shall be continuous through the trench, over the crest, and down the slope.

Geomembrane shall not be placed when ambient temperatures are less than 32 °F or more than 104 °F, measured 12 inches above the geomembrane. Placement shall not be attempted in rain, snow, or under conditions of excessive fog or dew. Placement will not be permitted in areas of ponded water or in the presence of excessive winds.

Equipment used for placement shall not damage the geomembrane or the subgrade by handling, trafficking, leakage of hydrocarbons, or in other ways. Personnel working on the geomembrane shall not engage in any activities or wear footwear that could damage the geomembrane. Direct contact of any heavy mechanical equipment with the geomembrane shall not be allowed.

Panels shall be carefully unrolled according to the manufacturer and fabricator’s instructions, and in a manner that does not scratch or crimp the geomembrane. Panels shall be aligned to minimize wrinkles or fishmouths, especially along the field seams.

Adequate precautions (e.g., placement of sand bags) shall be taken to minimize the likelihood of wind uplift.

Any field panel or part of a field panel that becomes seriously damaged shall be replaced at the direction of the CQA personnel. Minor damage (e.g., small wrinkles, crimp,) shall be repaired using approved procedures, as described in the specifications. Damaged field panels that have been rejected for use shall be removed from the site.

4.1.4.2 Geomembrane Field Seaming Methods and Equipment

Extrusion welding and dual track fusion welding are approved seaming methods. Fusion welding shall be utilized for tie‐in seams between existing and new geomembrane.

Seaming shall be a continuous process with a minimum of interruptions along any given seam.

Where conditions warrant, the installer may be allowed to use a temporary support surface between the geomembrane and the subgrade, to achieve proper support conditions during seaming operations. The use of such support methods shall be subject to the approval of the CQA Engineer. The support shall not be left in place and shall be removed on completion of seaming.

Wherever possible, wrinkles or fishmouths shall be pulled out of the overlap area prior to seaming. In situations that this cannot be done, they shall be cut along the ridge of the wrinkle, in order to achieve a flat surface. Such cuts shall be seamed. In situations that the overlap is inadequate, an oval or round patch of the same geomembrane, extending a minimum of 6 inches beyond the cut in directions, shall be seamed onto the geomembrane.

Extrusion Welding Process

Extrusion welding apparatus shall be equipped with gauges to measure the temperature at the nozzle or the preheat temperature of the apparatus. The CQA personnel shall monitor the extrudate and ambient temperature at appropriate intervals. The extruder shall be purged of heat‐degraded extrudate at the beginning of each seaming sequence.

Artificially induced cooling of extrudate welds (using water or any other means) shall not be allowed. Sufficient time between welding and non‐destructive testing shall be taken so that non‐destructive testing procedures do not cause artificial cooling of the extrudate.

Fusion Welding Process

Fusion welding apparatus shall be automated, self‐propelled devices that produce either a single seam or a double seam with an enclosed central air space. The apparatus shall be equipped with gauges that indicate the equipment temperatures during welding. For the seaming of cross‐seams, the top and bottom edges of the cross‐seam shall be ground to a smooth incline prior to seaming.

The CQA personnel shall log ambient and seaming apparatus temperatures, as well as seaming apparatus speed for each seam.

Seam Overlap and Preparation

Prior to seaming, geomembrane rolls or panels shall be overlapped by a minimum of 6 inches for extrusion welding and 5 inches for fusion welding, or as recommended by the manufacturer. Procedures used to bond adjacent rolls together temporarily shall not result in damage to the geomembrane. If mechanical devices, such as hot air leisters, are used for temporary bonding, the air temperature at the nozzle of such equipment shall be controlled so as not to damage the geomembrane. Solvents or adhesives shall not be used.

Seams shall be aligned to create as smooth a surface as practicable with a minimum amount of wrinkles and fishmouths. The area in the immediate vicinity of the seam shall be free of moisture, dust, dirt, debris, or any other foreign material and, if necessary, sheltered from wind and dust immediately, prior to, and during the seaming operation. If grinding is required along the seam, this shall be done according to the manufacturer’s recommendations, within 1 hour of the seaming operation and in a manner that does not damage the geomembrane. This process also shall include cleaning the seam area with a brush or forced air immediately prior to seaming. Particular care shall be paid to the condition of existing geomembrane prior to tie‐in with new geomembrane.

Weather Conditions

In general, seaming shall not be attempted when ambient temperatures are below 32 °F or above 104 °F, as measured 12 inches above the liner. Below 32 °F, seaming may be allowed, provided suitable precautions are taken and the installer is able to certify in writing that seaming under these conditions will not cause any chemical or physical alteration to the geomembrane, which may deleteriously affect its short or long‐term performance. Approval by the CQA Engineer will be required to seam with ambient temperatures are below 32 °F or above 104 °F. Extrusion welding will require the geomembrane to be preheated by either the sun or the use of a hot air device, and the installer shall take precautions that excessive cooling resulting from wind does not affect the seaming operation. CQA personnel shall determine when preheating is required and whether wind affects may be deleterious to seaming operations.

Seaming shall not be performed during wet weather in which the geomembrane is exposed to the elements.

Trial Seams

Trial seams shall be made to verify that adequate conditions exist for field seaming to proceed. Each seamer shall produce a trial seam at the beginning of each shift. Additional trial seams shall be made every 4 hours or, if a breakdown of the seaming equipment occurs, prior to resumption of seaming operations. The CQA personnel shall monitor and log the trial seam results.

Trial seams shall be made on pieces of geomembrane identical to the installed product measuring at least 2 feet long by 1 foot wide (after seaming) with the seam centered lengthwise and overlapped, as required for the particular seaming process. Seaming shall be conducted in the trench near the area where production seaming will occur.

Six 1‐inch wide samples shall be cut from the test seam and tested; three in shear and three in peel, using a tensiometer that has been calibrated within the past 6 months. The samples shall not fail in the seam. If a seam failure occurs, then a second seam shall be produced and tested. If a second failure results, the apparatus or seamer shall be rejected and shall not be used for field seaming until any deficiencies have been corrected. This shall be verified by the production and successful testing of two consecutive trial seams.

4.1.5 Non‐Destructive Testing of Field Seams

Seams shall be non‐destructively tested by the installer over their full length, to verify their continuity. It should be noted that this testing does not provide any information regarding seam strength. Non‐destructive testing shall be performed concurrently with field seaming using the equipment and procedures described below. Any seam that fails the non‐destructive test shall be repaired in accordance with approved procedures, as described in the specifications. Repairs shall be retested to determine the success of the repair.

Where CQA personnel determine that seams cannot be non‐destructively tested due to physical constraints, the seams shall be capped with the same geomembrane or double seamed. CQA personnel shall observe the seaming and capping of such seams to assess their adequacy and determine whether additional action is required. Where such a seam is accessible for testing prior to final geomembrane deployment, testing shall be performed prior to deployment.

4.1.5.1 Vacuum Testing

For extrusion welded seams, seams shall be evaluated using vacuum box testing. The vacuum box shall consist of a rigid housing with a transparent viewing window on top and a soft, flexible gasket attached to the bottom of the housing. A porthole and valve assembly along with a calibrated vacuum gauge shall be provided at one end of the housing. The vacuum gauge shall be calibrated, prior to initial use on the project and recalibrated on at least an annual basis, at the end of the project, or at the discretion of the CQA Engineer. The installer shall supply vacuum gauge calibrations to the CQA Engineer for review prior to the start of testing. A steel vacuum tank and pump assembly complete with the necessary pressure controls, pipe connections, pressure hoses, and fittings shall be provided. A soapy solution and a method of dispensing the solution are also required.

The tests shall be performed according to ASTM D5641. To perform the test, the pressure in the vacuum tank shall be reduced to approximately 5 inches of mercury. The soapy solution shall be applied to the test section, and the vacuum box placed over the wetted area. The bleed valve shall then be closed and the vacuum valve opened. Once a tight seal has been established, the test section shall be visually examined for a period of not less than 10 seconds, to determine whether bubbling of the soapy solution is occurring. The vacuum valve shall then be closed and the bleed valve opened. The vacuum box shall be removed and the process repeated on the next adjacent test section. A minimum 3‐inch overlap shall be provided on test sections. Locations where bubbling of the soapy solution is observed, shall be clearly marked for repairs to be performed in accordance with approved procedures, as described in the specifications. Repairs shall be retested.

The non‐destructive testing shall be conducted by the installer and continuously monitored by CQA personnel.

4.1.5.2 Air Pressure Testing

The ASTM D5820 test method shall apply only when the double hot wedge fusion seaming method is used to form the seam. The testing equipment shall consist of an air pump capable of generating and sustaining pressure of at least 40 pounds per square inch (psi) complete with a pressure gauge and the necessary pressure hose, fittings, and connections. An approved pressure feed device, such as a sharp hollow needle, shall be provided to penetrate into the central air channel at one end of the seam. A second calibrated pressure gauge in 1 psi increments capable of reading pressures up to 40 psi shall be provided to detect any pressure loss at the opposite end of the seam from the pressure feed device.

To perform the test, a section of the seam shall be sealed off at both ends. The pressure feed device shall be inserted into the air channel at one end of the sealed section, and the second pressure gauge shall be inserted into the opposite end of the air channel. If the seam is 1/2‐inch wide, it shall be pressurized to a minimum pressure of 30 psi. The pressure valve shall be closed and the pressure monitored for a period of not less than 5 minutes. If a pressure loss greater than 2 psi is observed at either end or if the required pressure cannot be reached, then the seam shall be rejected. If, in the judgment of the CQA personnel, significant changes in temperature occur during the test (e.g., due to cloud cover), the test shall be repeated after the geomembrane has stabilized. Faulty areas along the seam shall be identified, repaired in accordance with approved procedures, and retested. Holes created during non‐destructive testing shall be repaired in accordance with approved procedures, as described in the specifications upon completion of the test.

The non‐destructive testing shall be conducted by the installer and continuously monitored by CQA personnel.

4.1.6 Destructive Testing of Field Seams

Destructive testing of field seams shall be performed at selected locations in order to verify that seams satisfy the strength requirements listed in the specifications. Sampling and testing shall be done concurrently with field seaming operations so that corrective action, if required, may be implemented as the work progresses. Samples shall be taken for testing to achieve a minimum average daily frequency, as listed in Tables 4‐3.5. Sample locations shall be determined by CQA personnel based on the required sampling frequency and seaming observations. The installer shall not be informed in advance of the locations where the seam samples will be taken. Additional test locations may be required during seaming operations, such as along tie‐in seams with existing geomembranes. The necessity for such additional sampling and testing shall be determined by CQA personnel, and extra testing shall be performed when there is cause to suspect the presence of excess crystallinity, contamination, offset welds, or any other potential defect. The CQA Engineer may increase the minimum frequency of destructive testing as the work progresses, based on the results of previous testing.

Samples shall be cut by the installer under the observation of CQA personnel. Samples may be cut prior to non‐destructive seam testing. Each sample shall be numbered and identified. The sample number and location shall be recorded by CQA personnel on the layout drawings.

The test sample shall measure approximately 12 inches wide by 42 inches long with the seam centered lengthwise. Two 1‐inch wide strips shall then be cut, one from either end of the sample. Both of these strips shall be tested by the installer in the field using a tensiometer in order to determine the mode of failure in both peel and shear. The remaining portion of the sample shall be cut into three equal parts, having a minimum length of 12 inches. One sample shall be taken by CQA personnel for destructive testing under laboratory conditions. One sample shall be given to the installer to perform construction QC testing. The third sample shall be kept in storage by the Owner, if desired.

The area from which the test sample was cut shall be immediately repaired in accordance with approved procedures, as described in the specifications. Seams created for these repairs shall be non‐destructively tested in accordance with Section 4.2.6.

Neither of the field tests shall fail in the seams. The results of the laboratory testing by CQA personnel shall in any case determine the acceptability of the field seam. The tests shall be performed in accordance with the methods listed in Table 4‐2.1. Required test values are specified in Table 4‐3.5.

Passing values for field‐testing are defined in the specifications. Field‐testing shall meet these values for each test otherwise the seam will be considered failing.

A field seam shall only be considered acceptable when it is bounded by two destructive test locations that meet the seam strength requirements listed in the specifications, as well as passing the non‐destructive tests described in Section 4.2.6. Whenever a sample fails a destructive test, whether that test is conducted by field tensiometer, CQA laboratory, or the installer’s laboratory, the following procedures shall be employed. The installer shall have three options at their disposal, as follows:

The installer may cap the failing seam between any two passed test locations;

The installer may elect to trace the seam to two intermediate locations a minimum of 10 feet in either direction from the point of the failed test and take a small sample for an additional field test at each location. If these additional samples pass the test, then full samples shall be taken for CQA laboratory testing. If these laboratory samples pass the tests, then the seam shall be capped between these locations. If either sample fails, then the sampling and testing process shall be repeated to establish the zone over which the seam shall be capped; or

Cap all seams welded by the machine that had the failing test.

The continuity of capped seams shall be verified by non‐destructive testing in accordance with Section 4.2.6.

CQA personnel shall document actions taken in conjunction with destructive test failures.

4.1.7 Repairs

The entire geomembrane surface shall be examined by CQA personnel in order to confirm that the geomembrane is free of any defects, holes, blisters, undispersed raw materials, or contamination by foreign matter. Particular attention shall be paid to existing geomembrane in tie‐in areas. Whenever possible, the examination of the geomembrane surface shall be done prior to any seaming in that area. If necessary, the geomembrane surface shall be cleaned by the installer so that it is free of dust, mud, or any other materials that may inhibit a thorough examination of the surface. Any suspect areas shall be clearly marked by CQA personnel and non‐destructively tested by the installer, in accordance with Section 4.5.3. Any location that fails to pass the non‐destructive testing or from where a destructive test sample has been removed shall be repaired using one of the procedures described below.

Small tears, wrinkles, scratches, or pinholes shall be repaired by the installer using spot welding, seaming, or patching, as appropriate. Large holes and tears, undispersed raw materials, and any areas that have been contaminated by foreign matter shall be repaired by the installer using patches or by capping the area. All damage that fully penetrates the layers shall be repaired with a patch. Patches shall be round or oval in shape, shall consist of the same geomembrane material, and shall extend a minimum of 6 inches beyond the edge of the defect in all directions. Temporary bonding methods used to hold patches in place prior to seaming shall contain approved methods only. Geomembrane surfaces to be patched shall be abraded in accordance with the specifications. Surfaces shall be clean and dry at the time that the repair work is performed. Repair seaming shall be performed using approved extrusion welding methods and equipment.

Repairs shall be non‐destructively tested using the appropriate methods described in Section 4.2.6. Unless additional destructive testing is required, as described in Section 4.2.7, repairs that pass the non‐destructive test shall be accepted as being adequate. Any repairs that fail the non‐destructive test shall not be accepted, and the installer shall perform the necessary remedial work and retest the repaired area until it passes the non‐ destructive testing criteria.

Upon completion of field seaming and testing, and prior to any placement of materials on top of the geomembrane, CQA personnel shall identify any large wrinkles or fishmouths that may have been built into the geomembrane. Any such features shall be cut out, repaired, and tested by the installer.

In any given area, no work shall proceed with any materials that may cover the geomembrane until repairs in that area have been successfully made. As the work progresses, CQA personnel shall document locations requiring repair work and shall confirm that repairs have been successfully made.

4.1.8 Materials in Contact with Geomembrane

The requirements of this section are intended only to minimize the risk of geomembrane damage during installation on existing surfaces or during placement of overlying materials. The construction and material specifications shall govern the adequacy of construction using these overlying materials. Installer shall not perform any cutting, testing, or work on top of the geomembrane. All generators shall be kept off geomembrane.

Placement of materials on top of the geomembrane shall not be allowed when the ambient temperature is below 32 °F or above 104 °F.

Equipment used for placing and compacting overlying soil materials shall not be driven directly on to any geosynthetic material. A minimum thickness of 1 foot of material shall be maintained between the geomembrane and the low contact pressure bulldozer, or light motor grader, used to place granular materials. No sharp turning of the spreading equipment will be allowed on the initial 12‐inch cover. No heavy rubber‐tired vehicles shall be allowed in areas underlain by geomembrane until a minimum of 3 feet of soil cover material has been placed, with the exception that a light grader may be used on the 1‐foot cover for fine grading and trimming operations. However, the weight of the equipment may not exceed 5 psi, as measured on the geomembrane surface. Equipment shall be observed by the CQA personnel during placement to document that no leakage of hydrocarbons occurs, particularly on top of the geomembrane.

Placement of soil materials on top of the geomembrane shall not be allowed within 50 feet of any un‐seamed edge of geomembrane until field seaming of that edge is complete. This is required to allow sufficient room to work out any large wrinkles or fishmouths, prior to seaming.

The placement of cover materials shall be done with caution and in a manner that is least likely to cause wrinkles in, or damage to, the geomembrane. The CQA personnel shall monitor the placement of cover materials over the geomembrane, on a regular basis.

4.1.9 Post‐Construction

Upon completion of work in any given area, CQA personnel shall examine that area to determine whether waste and extraneous materials have been removed and that the area has been left in a satisfactorily clean condition, to allow placement of materials on top of the geomembrane.

4.2 Geocomposite Drainage Layers

CQA personnel shall review conformance testing on samples of the geocomposite material submitted by the manufacturer. These activities are described in the following sections.

4.2.1 Pre‐Construction

Tests on the geonets and geotextiles that are intended for use for the geocomposite shall be performed prior to geocomposite fabrication by the manufacturer and provided to the CQA engineer in advance of shipment for conformance with Tables in 4‐2.2, 4‐2.3, 4‐3.2 and 4‐3.3. Geocomposite fabricated from non‐conforming components shall be rejected at the subcontractor's expense.

The following tests will be performed on geocomposites, at a minimum:

Ply Adhesion (ASTM D7005)

Transmissivity (ASTM D4716)

4.2.2 Construction

Materials and work that fail to meet the requirements of these specifications shall be removed, disposed of, and replaced at the subcontractor's expense.

4.2.3 Handling and Placement

The geocomposites shall be handled and placed, as described below:

Geocomposites shall be handled by the subcontractor in such a manner as to ensure that these materials are not damaged.

The geomembrane surface shall be cleaned prior to placing geocomposite to remove dust, dirt, and debris.

On slopes, geocomposite may be deployed over slip‐sheets with the roll at the top of the slope. An alternative method is to secure the geocomposite, then roll it down slope in a manner to continually keep it in tension, if necessary, position the geocomposite after deployment to minimize wrinkles, and remove the slip‐ sheet, if used.

The geocomposite shall not be drug across textured geomembrane.

In the presence of wind, exposed geocomposites shall be weighted with ultraviolet (UV) resistant sandbags, or equivalent. Sandbags shall be installed during geocomposite placement and shall remain until replaced with cover material.

Unless otherwise specified, geocomposites shall not be welded to geomembranes.

Geocomposites shall only be cut using approved cutting tool.

During placement of the geocomposite, the subcontractor shall take necessary precautions to prevent damage to underlying layers.

During placement of geocomposites, care shall be taken not to entrap dirt or excessive dust that could cause clogging of the drainage system, and/or stones that could damage the adjacent geomembrane. If dirt or excessive dust is entrapped in the geocomposite, it shall be cleaned prior to placement of the next material on top of it.

Vehicles shall not be permitted on the geocomposite unless approved by the Contractor.

Tools shall not be left on or under the geocomposite.

In geocomposites, tearing the geotextile away from the geonet shall not be allowed, except at seam locations in corners, as approved by the CQA subcontractor.

After deployment, geocomposite shall be covered to prevent exposure to UV radiation (sunlight), within a maximum period of 14 calendar days.

4.2.4 Joining

The geocomposite drainage layers shall be joined, as described below:

Adjacent sections of geocomposite shall be overlapped, according to the manufacturer's directions.

Overlaps shall be secured by tying. Acceptable tying devices include plastic fasteners or polymer braid. Tying devices shall be white or yellow for easy observation. Metallic joining devices are not allowed.

Overlaps shall be secured every 1.5 meters (5 feet), along slopes and on the floor of the landfill. Along end‐to‐end seams, spot weld and tie two rows 75 millimeters (3 inches) apart. Spot weld and tie each row at 150 millimeters (6 inches) intervals; stagger weld or ties between rows.

No horizontal seams shall be allowed on sideslopes provided rolls can be manufactured to sufficient length. If required because of manufacturing limitation end seams shall be staggered.

If more than one layer of geocomposite is installed, joints shall be staggered.

Top geotextile component of the geocomposite shall be sewn.

4.2.5 Repair

The geocomposite shall be repaired, as described below:

Remove the damaged or un‐bonded area of geocomposite.

Cut a piece of geocomposite to fit over the repair area. Geocomposite shall fit over repair area and be tied similar to end‐to‐end seams.

Remove any dirt or other foreign material that may have entered the geocomposite.

Geocomposite damage greater than 4 square feet shall require removal of a full roll width of damaged area.

4.2.6 Materials in Contact with Geocomposites

The subcontractor shall place soil materials located on top of a geocomposite layer in such a manner as to ensure that the following conditions are satisfied:

No damage to the geocomposite;

No slippage of the geocomposite on underlying layers; and

No excess tensile stresses in the geocomposite.

Placement of soil materials shall begin at the bottom of the sideslopes and progress upslope, or laterally, at about the same elevation in such a manner that a full layer of material is covering the geosynthetics downslope, from the area being covered.

5 LEAK DETECTION AND LEACHATE EXTRACTION SYSTEM

The CQA personnel shall perform the activities discussed in this section.

5.1 Pre‐Construction

CQA personnel shall inspect LCS materials and components when they are delivered to the site to confirm that they conform to the design criteria and specifications. Receiving inspection shall be performed in compliance with the procedures specified in this CQA Plan. In general, activities performed by CQA personnel shall include the following:

Inspect materials upon arrival at the site to confirm conformance to the specifications;

Inspect piping components to confirm (from appearance and shipping documents) that they are constructed of materials, as listed in the plans, specifications, and procurement documents, and that they are not damaged.

Take measurements to confirm that pipe is of specified size and wall thickness and that perforations are sized and spaced as specified;

Observe and test to confirm that gravel materials conform to the specifications, are of the proper size and gradation, and do not contain unacceptable types of materials. Testing requirements for the leachate collection layer are outlined in Table 4‐1.2; and

Inspect to confirm that prefabricated structures are as specified in the design.

Such items include, but are not limited to, non‐HDPE piping systems, prefabricated HDPE components, electrical equipment, and monitoring equipment. Inspection shall include visual observation of any corrosion‐resistant coatings to document that they are present and without flaw.

5.2 Construction

5.2.1 Pipe Installation

The HDPE pipe network shall be placed according to the design. CQA monitoring activities shall include review of construction subcontractor’s submittals concerning joining methods and type of perforations;

review of manufacturer’s certification to document that the HDPE pipe meets the specifications;

observe and measure to confirm that the pipes are placed at specified locations and in specified configurations, and that pipe grades are as specified;

verify that the internal cleanliness of HDPE pipe is maintained.

visually observe that pipes are joined together and perforated in accordance with the approved procedures;

observe that the placement of any filter or backfill materials around the pipe conforms to the plans;

witness, review, and document testing of HDPE piping prior to being buried or covered with liner; and observe that backfilling and compaction are completed as specified and that, in the process, the pipe network is not damaged.

5.2.2 Aggregate Leak Detection

Inspection of the aggregate leak detection layer shall include:

testing the material to confirm that it meets the requirements in table 4‐1.2 and is free from excessive amounts of fines or organic materials;

measuring the thickness and observing coverage of each drainage layer as it is placed in the LCS (coordinate with CQA surveyor);

observing placement of geotextile as required; and surveying the completed layer to document that specified slopes and grades are obtained (coordinate with CQA surveyor). The survey tolerance for this layer is 0.0 to 0.2 feet, or the layer may be field verified.

Placement of the leak detection layer shall not damage any component of the underlying composite liner or the piping.

5.3 LCS System Equipment and Components

5.3.1 Electrical System and Pump Controls

The electrical system that controls the leachate pumps shall be checked for proper installation and operation. CQA personnel shall perform the following activities:

Receipt inspections of electrical components (e.g., verify Underwriters Laboratories (UL), listings);

Review construction subcontractor’s submittals and proposed equipment to document compliance with the specifications;

Verify and document final tagging, labeling, and marking of the electrical systems (e.g., breaker, outlets, disconnects, switches);

Perform or review component checks of resistance, grounding, and load prior to complete system check.

5.3.2 Pumps, Piping, Meters, and Valves

The pumps, piping, instruments (such as the flow meters), and valves that are included in the leachate collection (removal and transfer) system shall be examined and tested at the system level for conformance to the specifications and proper performance. CQA personnel shall perform the following activities, in conjunction with the following items:

Review construction subcontractor’s submittals and equipment deliveries to the site to verify conformance with the specifications;

Review the results of subcontractor’s acceptance testing of the piping system;

Review system performance checks to confirm operation, in accordance with the specifications; and

Review the complete leachate removal system performance using the installed pumps, as described in the specifications.

6 DOCUMENTATION

6.1 Daily Reports

Daily reports shall be completed by each of the CQA personnel when they are onsite. The CQA Engineer shall review each daily report. Entries may include, but not be limited to, the following information:

Reports on any meetings held and their results;

Equipment and personnel being used in each location, including subcontractors;

Descriptions of areas being observed, inspected, and documented;

Description of materials delivered to the site, including any quality verification (vendor certification) documentation;

Decisions made regarding use of material and/or corrective actions to be taken in instances of substandard quality;

Unique identifying sheet numbers of inspection data sheets and/or problem reporting and corrective measures reports used to substantiate the decisions described in the preceding item.

6.2 Design Changes and Clarifications

Requests for modifications to the CQA Plan or design changes shall be made by memorandum to the Owner, with copies to the CQA Engineer, and will require CDPHE approval.

6.3 Final Documentation

At the completion of the project, a final summary report that incorporates the field‐ testing and as‐built drawings shall be prepared by the CQA Engineer and submitted to the Owner and CDPHE. The as‐built drawings, which will be generated by a land surveyor licensed in the State of Colorado and retained by the Owner, shall include scale drawings depicting depths, plan dimensions, elevations, and fill thicknesses. The report shall include documentation of each construction component monitored by CQA personnel and shall certify that the facility was constructed in accordance with the CQA Plan, Technical Specifications, and drawings. The report shall be sealed by a professional engineer registered in the State of Colorado. Use of any newly constructed portion of the landfill shall commence after CDPHE approves the documentation report.

6.4 Storage of Records

During the construction at PCSWC, the CQA Engineer shall be responsible for CQA documents, including the following:

The CQA Engineer’s copy of the design criteria, plans, procedures, and specifications;

The CQA Plan; and

The originals of the data sheets and reports.

7 REFERENCES

Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division, 6 CCR 1007‐2, Part 1, Regulations Pertaining to Solid Waste Sites and Facilities § 9 Waste Impoundments, 2024.

FIGURES

F:\PITKIN COUNTY\2025\IMPOUNDMENT\CQA PLAN\REPORT.DOCX

Line of Authority

Construction CQA Engineer

CQA

Lab

WCG

Contractor Engineer Design

CQA

Surveyor

OWNER

PCSWC

Permitting Agency

CDPHE

TABLES

4‐1.1 Subgrade Structural Fill

Phase Material Test and ASTM Number Frequency Required Value

Pre‐Construction Soil

Grain Size Distribution (C136/D422) 1 per 5,000 cubic yards (cy) ‐‐

Atterberg Limits (D4318) 1 per 5,000 cy ‐‐

Standard Proctor Compaction (D698) 1 per 5,000 cy ‐‐

Construction Soil In‐Place Density (D6938) 1 per 750 cy

95% Standard Proctor max dry density moisture to provide compaction

Note: ASTM D2922 has been superseded by ASTM D6938

4‐1.2 Gravel Drainage

Phase Material Test and ASTM Number Frequency Required Value

Pre‐Construction Borrow Source

Grain Size Distribution (C136) 1 per 2,000 cubic yards (cy) ‐‐

Permeability (D2434) 1 per 2,000 cy ≥1x10‐2 cm/sec

Carbonate Content (D4373) 1 per 10,000 cy ‐‐

Construction Gravel, when delivered

Visual Observations Continuous ‐‐

Grain Size Distribution (C136) 1 per 2,000 cy ‐‐

Note: Gravel used around leachate collection pipe or within the sumps shall have a value of 1 centimeter per second (cm/sec) or greater.

4‐1.3 Anchor Trench

Phase Material Test and ASTM Number Frequency Required Value

Construction Soil Visual Observations Periodic ‐‐

4‐2.1 HDPE Geomembrane

Material Test and ASTM Number MQC Frequency CQA Test Frequency

Resin Manufacturer’s Documentation Certification and QC Test Results Every Lot N/A

Geomembrane

Manufacturer’s Documentation, Certification and QC Test Results

Every Roll N/A

Receiving Inspection N/A Every Roll

Thickness (D5994) Thickness for weld edges (D5199 mod.)

Asperity Height (D7466) Specific Gravity (D1505 or D792)

Yield Strength (D6693) Break Strength (D6693)

Elongation at Yield (D6693) Elongation at Break (D6693)

Tear (ASTM D1004) Puncture Resistance (D4833)

Stress Crack Resistance (D5369) Carbon Black Content (D4218) Carbon Black Dispersion (D5596)

Oxidative Induction Time (D8117 or D5885) Oven Aging at 85 °C (D5721, D8117, or D5885)

UV Resistance (D7238, 81178, or D5885)

Per roll Per roll

Every 2nd roll 200,000 lb 20,000 lb 20,000 lb 20,000 lb 20,000 lb 45,000 lb 45,000 lb per GRI GM10 20,000 lb 45,000 lb 200,000 lb

Per each formulation Per each formulation

Seam Overlap N/A Every Panel

Trial Seams N/A Every 4 hours per

Welder per Machine

Vacuum Test (D5641) N/A All Extrusion or Single Wedge Fusion Welds

Air Pressure Test (D5820) N/A All Double Wedge Fusion Welds

Seam Destructive Test (D6392) (5 peel/5 shear)

N/A Minimum Average of 1 per 500 feet per Welder

Extrudate Documentation and Certification Every Resin Lot N/A

Installation Surface

Installer’s Certification of a Suitable Installation Surface

N/A Each Installation

Surface

4‐2.2 Geotextile

Material Test and ASTM Number Frequency

Geotextile and Thread

Manufacturer’s Documentation, Certification, and Quality Control Test Results

Every 50,000 square feet per lot

Geotextile Cushion (8‐oz)

Mass per Area (D5261) Grab Tensile Strength (D4632) Grab Tensile Elongation (D4632) Trap. Tear Strength (D4533)

Puncture (CBR) Strength (D6241) UV Resistance (D7238)

Every 100,000 square feet per lot

Apparent Opening Size (D4751) Every Lot

4‐2.3 Geocomposite

Material Test and ASTM Number Frequency

Geocomposite Drainage Layer

200‐mil (Double‐sided)

Ply Adhesion (D7006) Per 200,000 lb

Transmiss…