1 

Operations and Maintenance Guidelines for Coal Ash Landfills 

Coal Ash Landfills are NOT the Same as 

Subtitle D Solid Waste Landfills 

Christopher D. Hardin, PE and Nick L. Perrotta, PE – Haley and Aldrich, Inc. 

1. INTRODUCTION: 

The number of coal ash landfills that have been constructed in the past five years has increased substantially 

since the promulgation of new State regulations for the handling and long-term storage of coal combustion 

residuals (CCRs). Many of these recently constructed coal ash landfills were designed using methods and 

materials that are common for Subtitle D, lined, municipal solid waste (MSW) landfills. Review of several 

landfill designs indicate that many CCR landfills have geotextile filter layers, leachate collection pipes, liner 

systems, stormwater management features and operational plans that are often just “reformatted” of a MSW 

landfill design. 

Owners and operators of coal ash landfills have experienced problems with the design and operational plans 

for their landfills that are attributable to a minor, but important differences between MSW, Subtitle D lined 

landfills and CCR landfills. This paper will discuss and evaluate these differences and provide practical 

solutions for providing a better design and operational control for coal ash landfills. 

The overall purpose of this paper is to initiate discussion and technical interaction on what constitutes an 

effective CCR landfill design. It is recognized that CCR landfill design is a new and developing sub-field in 

the area of landfill design that merits additional discussion to develop best practices and design methods. 

2. DIFFERENCES BETWEEN SOLID WASTE AND COAL ASH LANDFILLS 

To understand coal ash landfills that have experienced design and operational problems, it is helpful to 

consider the primary differences between the waste materials at MSW landfills and those at coal ash or CCR 

landfills. A few of the key differences are: 

Difference No.1 -- Particle Size: 

 Coal ash is a homogeneous, mostly fine particle material that requires special sizing of the 

geotextile or aggregate drainage/filter layer to prevent clogging. 

 MSW is a heterogeneous, large dimension, inconsistent size particles. 

Difference No. 2 – Odors and Vector Control: 

 Coal ash has very little organic fraction and therefore has almost no noticeable odor and off 

gases and minimal/no settlement issues. 

 Coal ash typically does not need daily cover to prevent disease and rodent issues. 

 MSW tends to have significant odor and vector issues if not placed, compacted and covered with 

daily cover soils or fabrics. 

 After placement, the organic material in MSW will continue to degrade producing methane and 

odors that must be managed and settlement issues. 

Difference No. 3 – Erodability and Moisture Sensitivity 

 As a predominately silt-sized particle, coal ash is susceptible to erosion. 

 Coal ash can lose strength quickly when in the presence of water if it is not compacted at or near 

the optimum moisture content. 

 Most MSW comes to the landfill several percentage points below its saturation moisture content, 

and can absorb large amounts of moisture without an immediate loss in shear strength. 

 MSW is not susceptible to erosion but is susceptible to blowing. 

Difference No. 4 – Dust Control 

 Coal ash can have significant issues with rapid surface drying, creation of dust and blowing of 

dust to off-site locations. These conditions can be difficult to control. 

 At times, MSW is also difficult to contain with fences required to catch blowing trash. 

 Most mixed MSW does not dry out as quickly as coal ash. 

2011 World of Coal Ash (WOCA) Conference – May 9-12, 2011 in Denver, CO, USA 

http://www.flyash.info/
2

3. COMMON PROBLEMS AND SOLUTIONS

This section will highlight a few of the common problems that have been encountered by operators of coal 

ash landfills. 

Problem No. 1: Ponded Surface Water above Leachate Collection Layers

It is common after the initial layers of ash have been placed for the surface water and runoff to build up in 

the landfill. This greatly reduces the collection system efficiency and the available storage volume in the 

landfill. It is often assumed that this is caused by plugged geocomposite and geonets. Recent testing 

indicates that the geocomposites and geonets still maintain a higher permeability than lose or compacted coal 

ash. This suggests that the problem is not with the geotextile or leachate collection layer, but the reduced 

infiltration rate of leachate through the compacted layers of coal ash. 

To allow drainage of run-off from the surface of the coal ash to reach the .leachate collection layer, some type 

of vertical/horizontal connection to the leachate collection system using a “chimney drain” or a “drainage 

layer” is often required. Chimney drains are typically constructed in sections as the CCR is placed, and 

connected directly to the horizontal leachate collect system. See Figure 1.

A few important considerations for the design and installation of chimney drains: 

 Locate the drains at a frequent enough spacing to handle runoff from large interior drainage 

areas that could occur during a wide variety of interim fill conditions.

 Size the chimney drain pipe and inlet for Peak Flow with a percentage of the surface water 

diverted to chimney drains and leachate collection system, based on a 10-year to 25-year storm. 

 Divert most of the surface water away from the chimney drains and to surface water collectors 

without contacting the CCR material. This may require the installation of soil berms to control 

runoff/run-on, and rain covers to prevent infiltration of surface water.

 Provide adequate surface water diversion to direct large storm events to stormwater management 

ponds instead of overtopping the CCR landfill embankments. This may require redundant 

stormwater channels and/or interim soil diversion berms as part of the CCR landfill plans. 

 Include daily inspection, cleanout and maintenance of chimney drain inlets in the operation and 

maintenance plan for the CCR landfill.

Drainage layers are typically constructed as the CCR is placed, and connected directly to the leachate collect 

system. See Figure 2.

A few important considerations for the design and installation of drainage layers: 

 Generally, CCR is placed in 15-30 foot–thick lifts sandwiched between 1-2 foot–thick drainage 

layers of granular drainage material. The drainage layer is placed at a minimum 5-percent slope, 

toward exterior and interior berms, to promote drainage and dewatering of the CCR layers.

 The CCR is placed and compacted in a controlled manner such that stormwater sheets off 

toward the leachate collection system. 

 The granular drainage material may be segregated bottom ash or other waste byproduct that 

exhibits a homogeneous particle size suitable.

 Perform annual NDG testing to document CCR is placed and compacted in accordance with the 

approved design.

 Perform as-built surveys to document each drainage layer has been constructed in accordance 

with the approved design.
3

Problem No. 2: Undersized Stormwater Management and Sediment Control Structures

As mentioned in the previous section, coal ash is a silt-sized particle that is highly susceptible to erosion and 

changes in moisture content. This material characteristic frequently results in stormwater management 

ponds (SWMP) and erosion control (E&S) devices that are filled with coal ash to capacity at more frequent 

intervals. These tendencies must be accounted for in the design by providing additional storage capacity 

and/or more frequent pond cleanouts and maintenance. 

A few important items to consider in the design of SWM ponds and E&S devices on CCR landfills include:

 More frequent rock check dams in the surface water channels draining to the SWM ponds. 

Require more maintenance and cleanout of devices to account for silt-sized, more erodible coal 

ash.

 Consider the design of a two-stage SWM pond with smaller fore-bay structure that can be 

cleaned at more frequent intervals. 

 Consider the use of turbidity curtains and other methods to promote settling and removal of siltsized particles 

 Oversize SWM ponds and E&S devices to account for the increased volume of silt-sized coal ash 

particles. 

 Monitor the levels in ponds to verify when it is time to clean.

Problem No. 3: Dust Control and Blowing Ash

As a silt-sized material, coal ash is “notorious” for rapid surface drying that produces dust within a few hours 

after the initial placement and compaction. Common solutions include continuous spraying with water and 

covering with cover soils. Other solutions include:

 Minimizing the size of the “working face” or CCR placement area so that wetter, partially 

saturated ash is placed over drying layers.

 Placement of surface encapsulation product like Posi-shell and Gorilla Snot at the end daily 

operations.

 Covering with temporary geotextile or raincovers that can be reused and moved to new 

placement areas as the fill placement progresses. 

4. DESIGN SOLUTIONS FOR COAL ASH LANDFILLS

This section provides a summary of a few design methods that have been used on coal ash landfills to 

increase the efficiency of CCR placement and compaction. By providing this summary the authors of the 

paper also recognize that there are many new and innovative ideas that are currently being used on other sites 

that are not mentioned. 

4.1 Leachate Collection and Geotextile Design

To avoid the potential of a clogged and/or blocked leachate collection system during a major storm 

event, the components of the leachate collection system must be designed to handle silt-sized 

particles. The design may include a combination of redundant measures like over-sized silt traps 

and/or more frequent maintenance of the inlet structures and geotextile surface. 

A few important items to consider for the design of the leachate collection system on CCR Landfills:

 Use laboratory clog tests to determine the geotextile and CCR clogging potential (ASTM D5101) 

and use the reduced drainage value for selection of the geotextile/geonet drainage materials. 
4

 Design inlets to the leachate collection system and chimney drains with sufficient freeboard to 

allow settling and minimize material transport into horizontal drain pipes. 

 Include frequent inspections of the geotextile surface of the leachate collection and/or chimney 

drain in the landfill operation and maintenance plan to prevent clogging of the leachate 

collection system 

4.2 Leachate Collection and Aggregate Filter Design

Also used to avoid the potential of a clogged and/or blocked leachate collection system during a 

major storm event, the inclusion of an aggregate filter in combination with the leachate collection 

system. 

A few important items to consider for this design of the leachate collection system on CCR Landfills:

 Proper selection of stone/gravel/sand to place directly over and around leachate collection 

piping to meet the required piping and hydraulic conductivity ratios which will help maintain 

long-term transmission of the leachate as well as not clogging and pipe protection.

 A 1-foot–thick granular drainage material is placed above the liner to act as a conduit for 

leachate, to provide efficient collection, and to protect the liner from operational loads and 

climatic effects

 Use heavy wall perforated and non-perforated piping with cleanouts that can be jetted annually 

to ensure pipe hydraulic capacity.

4.3 Interim Fill and Stormwater Management Plans

The placement and compaction of CCR materials can vary from site to site depending on the 

moisture content of the coal ash, the distance from the point of generation, and the need to provide 

dewatering or drying prior to placement. One of the best ways to avoid the common problems 

listed in the previous section is to develop carefully thought out fill plans that show the contractor 

where to install haul roads, place and compaction of CCR materials, and how to route stormwater 

from the working face. A few important items to remember for the development of CCR fill plans 

are:

 Design the haul roads and stormwater management channels so that surface water is 

directed away from the working face and to sediment traps, chimney drain inlets and/or 

drainage layers.

 Attempt to work the placement and compaction of CCR materials as compacted 

embankment instead of an “end dumped” waste material. 

 Specify a maximum lift thickness and range of acceptable moisture contents for CCR

materials prior to compaction.

 Provide locations for moving stockpiles of interim cover materials and/or staging areas for 

dust control methods and materials.

 DO NOT submit the interim fill plans as an item for regulatory approval. Fill plans are an

operations activity that requires flexibility for the Contractor to account for changing 

weather and site conditions. 

 Include probable location for interim stormwater management and E&S control measures, 

but allow Contractor flexibility to account for changing conditions. 

 Design drainage channel slopes that reduce erosion and haul road grades that can be safely 

handled by standard construction equipment. Hint: Gradual drainage and haul roads

flatter than 10 percent work best. 
5

5. SUMMARY AND CONCLUSIONS

This paper and presentation was developed to provide a few ideas of what the authors have used effectively 

on CCR landfills and other industrial waste landfill designs. The information presented is by no means 

meant to provide the “final word” and/or a “checklist” for CCR landfill design. The main purpose of this 

paper is to encourage fellow landfill design engineers and CCR landfill owners and operators to STOP and 

THINK about the current methods used for CCR landfills. It is the author’s opinion that simply using 

“reformatted” MSW landfill designs will not work for the design, construction, operation and closure of CCR

landfills. 

A secondary purpose of this paper is to initiate discussion and technical interaction on what has worked 

effectively for CCR landfill design and construction. It is our hope that this discussion and technical 

interaction will result in even better CCR landfill designs, and continued protection of the environment. 
1 Haley & Aldrich, Inc. 

Operations and Maintenance Guidelines 

for Coal Ash Landfills 

Christopher D. Hardin, PE 

Nick L. Perrotta, PE 

Haley & Aldrich, Inc. 

7926 Jones Branch Drive 

McLean, Virginia 22102-3363

Reference: http://msnbcmedia3.msn.com/j/ap/coal%20ash%20disposal--1658380019 

2011 World of Coal Ash (WOCA) Conference – May 9-12, 2011 in Denver, CO, USA 

http://www.flyash.info/
Haley & Aldrich, Inc.

INTRODUCTION

Coal Ash Landfills are NOT the Same as 

Subtitle D Solid Waste Landfills 

• The number of CCR landfills has increased substantially 

with recent State and Federal regulations. 

• Many recently constructed CCR landfills were designed 

using methods and materials from Subtitle D lined, 

municipal solid waste (MSW) landfills. 

• Review of multiple designs indicate that many design 

features in CCR landfills are often just “reformatted” from a 

MSW landfill design. 

• CCR owners and operators have experienced problems that 

are attributable to the minor, but important differences 

between CCR and MSW Subtitle D lined landfills. 
Haley & Aldrich, Inc.

• Intent and purpose of this presentation

• Discuss and evaluate the differences between coal ash and 

MSW as a waste material

• Identify common problems and recommended solutions

• Drill down on three important design solutions

• Few hints and recommendations for CCR landfill O&M Plans

• Summary and Discussion: Ideas and questions from the 

attendees

AGENDA
Haley & Aldrich, Inc.

INTENT AND PURPOSE

• Initiate discussion and technical interaction on what 

constitutes an effective CCR landfill design. 

• Recognize that CCR landfill design is a new and developing 

sub field in the area of landfill design, that merits additional 

discussion to develop best practices and design methods.

• Encourage participation in the ACAA technical committee 

and possible subcommittee for CCR landfills

• Encourage additional research on issues unique to CCR 

landfills
Haley & Aldrich, Inc.

DIFFERENCES BETWEEN SOLID WASTE 

AND COAL ASH LANDFILLS

• To understand why coal ash landfills that have experienced 

design and operational problems, it is helpful to consider the 

primary differences.

• Difference No.1 -- Particle Size: 

• Coal ash is a homogeneous, mostly fine particle material that requires 

special sizing of the geotextile or aggregate drainage/filter layer to 

prevent clogging. 

• MSW is a heterogeneous, large dimension, inconsistent particle size 

material.
Haley & Aldrich, Inc.

DIFFERENCES BETWEEN SOLID WASTE 

AND COAL ASH LANDFILLS

• Difference No. 2 – Odors and Vector Control: 

• Coal ash has very little organic fraction and therefore has almost no 

noticeable odor and off gases and minimal/no settlement issues. 

• Coal ash typically does not need daily cover to prevent disease and 

rodent issues.

• MSW tends to have significant odor and vector issues if not placed, 

compacted and covered with daily cover soils or geotextiles

• After placement, the organic material in MSW will continue to degrade 

producing methane, odors and settlement issues that must be 

managed.
Haley & Aldrich, Inc.

DIFFERENCES BETWEEN SOLID WASTE 

AND COAL ASH LANDFILLS

• Difference No. 3 – Erodability and Moisture Sensitivity

• As a predominately silt sized particle, coal ash is susceptible to 

erosion.

• Coal ash can lose strength quickly when in the presence of water, if it 

is not compacted at or near the optimum moisture content.

• Most MSW comes to the landfill several percentage points below its 

saturation moisture content, and can absorb large amounts of 

moisture without an immediate loss in shear strength. 
Haley & Aldrich, Inc.

DIFFERENCES BETWEEN SOLID WASTE 

AND COAL ASH LANDFILLS

• Difference No. 4 – Dust Control

• Coal ash can have significant issues with rapid surface drying, 

creation of dust and blowing of dust to off site locations. These 

conditions can be difficult to control.

• At times, MSW is also difficult to contain with fences required to catch 

blowing trash.

• Most mixed MSW does not dry out as quickly as coal ash.
Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 1: Ponded Surface Water above Leachate

Collection Layers

• It is common after the initial layers of ash have been placed for the 

surface water and stormwater runoff to build up in the landfill. 

• This greatly reduces the collection system efficiency and the available 

storage volume in the landfill. 

• It is often assumed that this is caused by plugged geocomposite and 

geonets. 

• Recent testing indicates that geocomposite geonets still maintain a 

higher permeability than lose or compacted coal ash. 
10 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 1: Ponded Surface Water above Leachate

Collection Layers

• This suggests that the problem is not with the geotextile or leachate

collection layer, but attributable to the reduced infiltration rate of 

leachate through the compacted layers of coal ash. 

• To allow drainage of run off from the surface of the coal ash to reach 

the leachate collection layer, some type of vertical/horizontal 

connection to the leachate collection system using a “chimney 

drain” or a “drainage layer” is often required. 

• Chimney drains and drainage layers are typically constructed in 

sections as the CCR is placed, and connected directly to the 

horizontal leachate collect system. 

• See Solutions A, B, and C. Figures 1 and 2.
11 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 1: Solution A -- Chimney Drains 

• A few important considerations for the design and installation of 

chimney drains: 

Locate the drains at a frequent enough spacing to handle runoff from 

large interior drainage areas that could occur during a wide variety of 

interim fill conditions. 

Size the chimney drain pipe and inlet for Peak Flow with a smaller 

percentage of the surface water diverted to chimney drains and 

leachate collection system, based on a 10 year to 25 year storm. 

Divert most of the surface water away from the chimney drains and 

to surface water collectors without contacting the CCR material. 

This may require the installation of soil berms to control runoff/run

on, and rain covers to prevent infiltration of surface water.
12 Haley & Aldrich, Inc.

FIGURE 1 – Typical Chimney Drain
13 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

Problem No. 1: Solution B – Divert Stormwater & Maintenance

A few important design and operation considerations for SWM devices 

at CCR landfills include: 

Provide adequate surface water diversion to direct large storm 

events to stormwater management ponds instead of overtopping the 

CCR landfill embankments. 

Do not exclusively rely on pumping or siphons to control ponded

stormwater water over leachate lines. Pumps can fail, siphons plug.

Require redundant stormwater channels and/or interim soil diversion 

berms as part of the CCR landfill plans. 

Include daily inspection, cleanout and maintenance of chimney drain 

inlets in the O&M plan for the CCR landfill.

Hint: When considering the cost of additional leachate control 

measure, remember to look at the life cycle cost of an NOV. 
14 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 1: Solution C – Drainage Layers

• A few important considerations for the design and installation of drainage 

layers: 

 Generally, CCR is placed in 15 to 20 foot–thick layers (1 to 2 foot lifts) 

sandwiched between 1 2 foot–thick drainage layers of granular drainage 

material. The drainage layer is placed at a minimum 5 percent slope, 

toward exterior and interior berms, to promote drainage and dewatering of 

the CCR layers.

 The CCR is placed and compacted in a controlled manner such that 

stormwater sheets off toward the leachate collection system. 

 The granular drainage material may be segregated bottom ash or other 

waste byproducts that have a consistent particle size.

 Perform regular moisture density/compaction testing to document how the 

CCR is placed and compacted in accordance with the approved design.

 Perform as built surveys to document that the drainage layers have been 

constructed in accordance with the approved design and at the 

recommended locations. 
15 Haley & Aldrich, Inc.

Quality Control Testing for CCR 

Placement

• For slope stability, decreased 

permeability and reduced 

erodability specify the percent 

compaction and moisture 

content. 

• Typical values for CCR are 90 

to 95 percent of the Standard 

Proctor at +/ 5 percent of the 

OMC.

• Verify placement and 

compaction by a system of 

regular observation and testing.

Reference: http://www.google.com/imgres?imgurl=http://www.leomo.info/leomobg2010

Reference: http://www.ifandp.com/article/001894.html
16 Haley & Aldrich, Inc.

FIGURE 2 – Typical Interim Drainage Layers
17 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 2: Undersized Stormwater Management and 

Sediment Control Structures

• Coal ash is a silt sized particle that is highly susceptible to erosion and 

changes in moisture content. 

• This material characteristic frequently results in stormwater

management ponds (SWMP) and erosion control (E&S) devices that 

are filled with coal ash to capacity at more frequent intervals. 

• These tendencies must be accounted for in the design by providing 

additional storage capacity and/or more frequent pond cleanouts and 

maintenance. 
18 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 2: Solutions

• A few important items to consider in the design of SWM ponds and 

E&S devices on CCR landfills include:

More frequent rock check dams in the surface water channels 

draining to the SWM ponds. Require more maintenance and 

cleanout of devices to account for silt sized, more erodible coal ash.

Consider the design of a two stage SWM pond with smaller fore bay 

structure that can be cleaned at more frequent intervals. 

Consider the use of turbidity curtains and other methods to promote 

settling and removal of silt sized particles before the outlet structure. 

Oversize SWM ponds and E&S devices to account for the increased 

volume of silt sized coal ash particles. 

Monitor the levels in ponds at more frequent intervals to verify when 

it is time to clean. SWM ponds at CCR landfills can fill up FAST

with sediment!
19 Haley & Aldrich, Inc.

COMMON PROBLEMS AND SOLUTIONS

• Problem No. 3: Dust Control and Blowing Ash 

• As a silt sized material, coal ash is “notorious” for rapid surface drying 

that produces dust within a few hours after the initial placement and 

compaction. 

• Problem No. 3: Solutions

• A few important considerations for dust control and blowing ash: 

Common solutions include continuous spraying with water and 

covering with cover soils. Maybe a full time sprinkling system. 

Minimizing the size of the “working face” or CCR placement area so 

that wetter, partially saturated ash is placed over drying layers.

Placement of surface encapsulation product like Posi shell and 

Gorilla Snot at the end daily operations.

Covering with temporary geotextile or raincovers that can be reused 

and moved to new placement areas as the fill placement 

progresses. 
20 Haley & Aldrich, Inc.

DESIGN SOLUTIONS FOR COAL ASH 

LANDFILLS

• Leachate Collection: Inlet Design and Geotextiles

• Leachate Collection: Aggregate Filter Design

• Interim Fill and Stormwater Management Plans
21 Haley & Aldrich, Inc.

CCR Leachate Collection System 

• To avoid the potential of a clogged and/or blocked leachate collection 

system during a major storm event, the components of the leachate

collection system must be designed to handle silt sized particles. 

• Two design considerations are discussed:

• Inlet structures and geotextile surface.

• Aggregate filter.
22 Haley & Aldrich, Inc.

Leachate Collection: Inlet Design and 

Geotextiles

• A few important items to consider for the design of the 

inlets, geotextile selection and maintenance. 

 Design inlets to the leachate collection system and chimney drains with 

sufficient freeboard to allow settling and minimize material transport into 

horizontal drain pipes. 

 Apparent Opening Size (AOS) relative to the particle size of the coal ash 

becomes an important design parameter.

 Use laboratory clog tests to determine the geotextile and CCR clogging 

potential (ASTM D5101) and use the reduced drainage value for 

selection of the geotextile geonet drainage materials.

 Include more frequent inspections of the geotextile surface of the 

leachate collection and/or chimney drain in the landfill O&M plan to 

prevent clogging of the leachate collection system. 
23 Haley & Aldrich, Inc.

Leachate Collection: Aggregate Filter Design

• A few important items to consider for the design of 

aggregate filters:

Proper selection of stone/gravel/sand that is placed directly over and 

around leachate collection piping to meet the required piping and 

hydraulic conductivity ratios. This will help maintain long term 

transmission of the leachate, minimize clogging and provide pipe 

protection. 

A 1 foot–thick granular drainage material is placed above the liner to 

act as a conduit for leachate, to provide efficient collection, and to 

protect the liner from operational loads and climatic effects

Use heavy wall perforated and non perforated leachate pipe with 

cleanouts that can be jetted annually to maintain pipe hydraulic 

capacity. 
24 Haley & Aldrich, Inc.

• One of the best ways to avoid common problems is to develop 

carefully thought out fill plans that show the contractor where to install 

haul roads, place and compaction of CCR materials, and how to route 

stormwater from the working face. 

• A few important items to remember for the development of CCR fill 

plans are:

Design the haul roads and stormwater management channels so 

that surface water is directed away from the working face and to 

sediment traps, chimney drain inlets and/or drainage layers.

Attempt to work the placement and compaction of CCR materials as 

a compacted embankment instead of an “end dumped” waste 

material. 

Show the location and sizing of larger stormwater management 

channels along haul roads to avoid overtopping and erosive 

velocities. 

Interim Fill and Stormwater Management 

Plans
25 Haley & Aldrich, Inc.

DESIGN SOLUTIONS FOR COAL ASH 

LANDFILLS – Other Items

 Specify a maximum lift thickness and range of acceptable moisture 

content for CCR materials prior to compaction.

 Provide locations for stockpiles of interim cover materials and/or staging 

areas for dust control methods and materials.

 DO NOT submit the interim fill plans as an item for regulatory approval. 

Fill plans are an operations activity that requires flexibility for the 

Contractor to account for changing weather and site conditions. 

 Include probable location for interim stormwater management and E&S 

control measures, but allow Contractor flexibility to account for changing 

conditions. 

 Design drainage channel slopes that reduce erosion and haul road 

grades that can be safely handled by standard construction equipment. 

Hint: Gradual drainage channels and haul roads flatter than 10 percent 

work best. 
26 Haley & Aldrich, Inc.

SUMMARY AND DISCUSSION:

• This paper and presentation provides a summary of methods that have been 

used successfully on CCR Landfills primarily in the Southeastern US. By no 

means the final word! 

• Primary purpose of this paper and presentation: 

• To encourage fellow landfill design engineers and CCR landfill owners and 

operators to STOP and THINK about the current methods used for CCR 

landfills. 

• Our opinion is that simply using “reformatted” MSW landfill designs will not 

work for the design, construction, operation and closure of CCR landfills. 

• A secondary purpose: 

• Initiate discussion and technical interaction on what has worked effectively for 

CCR landfill design and construction. 

• Our hope that this discussion and technical interaction will result in even 

better CCR landfill designs, and continued protection of the environment.