Dam Structure Safety Installation and Repair Using Advanced Geosynthetic Technology

Posted May 22, 2025 by Ashley Beyer

Written By: Samantha Justice, P.E.

Dams and Spillways Are a Critical Part of U.S. Infrastructure

With over 91,000 structures nationwide, dams and spillways are essential for controlling flooding, water distribution, and providing hydroelectric power. However, these structures cannot last forever. The average age of dams and spillways in the U.S. is now 61 years, which is significantly over the typical 50-year lifespan of these structures. Aging infrastructure can lead to serious consequences if safety precautions are not taken or measures are not implemented to address identified problems promptly. Continual inspection and upkeep are crucial for any dam manager.

The 2025 Infrastructure Report Card by the American Society of Civil Engineers upgraded the condition of U.S. dams from a “D” to a “D+”, reflecting modest improvements but still highlighting the critical need for ongoing repairs and maintenance. State and federal regulations provide a framework for assessing and maintaining dam and spillway structures, requiring at least yearly audit inspections to identify areas needing repair or replacement. Performing these repairs can help extend the lifetime of dams, maintaining essential services without excessive costs or increased failure potential.

Understanding Areas of Concern for Existing Structures

The vast majority of America’s rivers and lakes have existing dams and spillways, and as such, very few new structures are being built. With new construction, safety measures can be incorporated during the design phase to extend the lifetime of the project and help prevent failures. The true threat is with existing structures that have gone past their intended lifetimes or have seen areas of potential failure.

A recent example of the potential for catastrophic damage due to a dam failure is the 2017 Oroville Dam crisis in Northern California. Extremely heavy rainfall over a number of days raised the level of Lake Oroville, increasing the flow over the main spillway to above-average levels. Almost immediately, damage was observed in the lower half of the spillway, with a large section of the concrete path collapsing. The emergency spillway was utilized to help prevent further damage to the main spillway; however, excessive erosion occurred to the emergency spillway path, and emergency repairs were subsequently required to address damage in both spillway areas.

Further damage occurred when more rainfall increased the lake level yet again, including blocking the downstream river and requiring the immediate shutdown of the Oroville hydroelectric power plant. Luckily, total collapse of the dam did not occur, but more than 180,000 residents of the Feather River Basin were required to evacuate for multiple days, and over the next year, more than 1,000 people worked more than 2 million hours to rebuild the spillways to ensure the safety of downstream communities.

With federal funding support from the Infrastructure Investment and Jobs Act (2021), states have access to resources for upgrading aging dams and spillways before failures occur. For example, the Oroville Dam crisis in 2017 followed the rejection of a 2005 proposal to build a concrete emergency spillway — an upgrade that could have prevented the damage.

Re-evaluating existing structures to ensure they can withstand 100-year and 500-year flood events remains essential. Regular maintenance of upstream and downstream dam faces, spillways, and even work pads and access roads supports safety by enabling faster inspections and repairs. These proactive steps help extend the lifespan of critical infrastructure and reduce the risk of costly emergencies.

GEOWEB® Geocells Are a Repair Solution for Dams and Spillway Sites

GEOWEB geocells offer long-term solutions for common dam and spillway challenges. Geocells function as the support structure for unpaved roadways, capable of supporting maintenance and repair vehicles. They also function as surface erosion control solutions, preventing the formation of rills or the collapse of unstable soils due to water flow, wave action, and storm events.

GEOWEB geocells can be placed on the upstream face of a dam structure to mitigate the effects of wave action on the dam, supporting existing riprap areas, or replacing them entirely with vegetation, gravel, or concrete. The flexibility of the GEOWEB system allows for the use of mixed infill materials, such as topsoil above normal water levels for grass growth and small aggregate below the water level for erosion prevention. Comprised of high-density polyethylene (HDPE), GEOWEB geocells are formulated for long term durability to resist weathering, chemical attack, and ultraviolet radiation, and are therefore suitable for use in applications where the material will be subjected to cyclic wetting and drying, permanently submerged, or full sun exposure. The material is not prone to degradation or corrosion due to environmental factors and can be placed on the downstream face or within a spillway structure. The system is also compatible with concrete infill to accommodate extremely high flow velocities. For comparison, Table 1 summarizes allowable velocities and shear stresses for various channel lining alternatives.

Comparison of allowable velocity and shear stress for channel lining alternatives

In emergency spillway areas, topsoil infill with vegetation can be used to allow for a natural camouflaged look, while still preventing erosion and uncontrolled water flow, and outperforming traditional unreinforced channel lining alternatives.

Staging areas and maintenance roads are also integral parts of a dam site, and when necessary, these features provide vital access and adequate ground support for vehicles and heavy equipment to perform inspections, routine maintenance, and repairs. The GEOWEB system can be used in a variety of load support applications, including unpaved access roads, laydown areas, and parking lots. Reinforcing these roads means significantly reduced maintenance requirements, reduced rutting, and access to areas that might otherwise be unable to support heavy loads due to soft soil conditions. Minimizing stresses on top of dam structures is critically important to preventing the formation of cracks or slumps within the structure that could lead to failure. The GEOWEB road system can be integrated with the slope protection system on the upstream and downstream faces of the dam for a continuously protected berm from water, vehicle, and impact loads.

Design Support & Resources for the GEOWEB System Applications

The engineering team at Presto Geosystems works closely with engineers and project planners, offering free project evaluation services and on-site support. Our recommendations will deliver a technically sound, cost-effective solution based on four decades of accredited research and testing data. Please contact our knowledgeable staff and network of qualified distributors and representatives to discuss your project needs today.

ASCE Reveals the 2025 Infrastructure Report Card

Posted April 11, 2025 by Ashley Beyer

The American Society of Civil Engineers (ASCE) recently released their quadrennial Infrastructure Report Card. America’s infrastructure earned an overall grade of C, which is a minor improvement over 2021’s grade of C-minus and the highest grade received since the report card’s inception in 1998. While the report card is trending in the right direction, we are not quite ready to hang it on the fridge.

There is still a lot of work and investment required to make up for decades of underinvestment and deferred maintenance, especially as climate change, population growth, and aging systems continue to place added stress on our infrastructure. Without sustained funding, strategic planning, and public-private collaboration, many critical systems — from levees and roads to drinking water and stormwater management — will remain vulnerable and inefficient.

The report card assesses and assigns grades to 18 categories of American infrastructure, including Bridges, Energy, Ports, Rail, Roads, and Stormwater. Half of the categories received a grade in the “D” range. This means that the civil engineers who evaluated these categories determined that the infrastructure is “poor, at risk.” According to the report card, this is, “…a clear sign that more needs to be done to improve the health of America’s built environment.”

Categories that received a grade in the “D” range include Dams, Energy, Levees, Roads, Schools, Stormwater, Transit, and Wastewater. These systems are critical to the overall health and wellbeing of our communities, and vital to commerce and economic stability at local, regional, and national levels.

Solutions to Improve America’s Infrastructure Grade

The 2025 Infrastructure Report Card underscores that while recent progress is promising, significant challenges remain. Federal investment through landmark legislation like the Infrastructure Investment and Jobs Act (IIJA) and the Inflation Reduction Act (IRA) has helped reverse decades of stagnation, but the work is far from done. According to ASCE’s 2024 Bridging the Gap study, an additional $2.9 trillion is still needed across 11 infrastructure sectors to reach and maintain a state of good repair — a level that would earn a “B” on the Report Card.

Closing this investment gap won’t just result in higher grades, but it will also create tangible economic relief for American families. If Congress maintains recent funding levels, the average household could save $700 annually by avoiding the hidden costs of failing infrastructure, such as delays, emergency repairs, and increased utility and transportation expenses.

Meanwhile, climate-related threats continue to intensify. Infrastructure systems, particularly aging roads, levees, dams, and water networks, face mounting risks from flooding, hurricanes, wildfires, and extreme temperatures. Investing in resilience now means fewer rebuilds later, and more reliable infrastructure to support economic growth and public safety.

Building Resilient Infrastructure with Geosynthetics

The future success of many infrastructure projects depends on the strength of the underlying soil. Through an interconnected honeycomb-like network, 3D geocells confine and stabilize soils that would otherwise be unstable under loading. The GEOWEB® 3D Soil Stabilization System is the industry’s first and most complete geocell system, designed with fully engineered components to withstand the most challenging site conditions. These accessories are engineered for strength, fast installs, and reliable long-term performance.

Whether used for load support, channel protection, slope stabilization, stormwater management, or retaining wall systems, the GEOWEB system enables cost-effective, low-maintenance infrastructure that stands up to environmental stresses. Its flexible design and engineered accessories ensure fast installation and long-term performance, even under challenging conditions.

At Presto Geosystems, we support engineers and project owners with free project evaluation assistance and technical guidance from project start through construction.

Learn more about how the GEOWEB geocells can be used to improve resilience in the lowest-graded categories.

Download the full 2025 Infrastructure Report Card >>

Presto Geosystems Announces Environmental Product Declaration (EPD) for Geocells

Posted April 10, 2025 by Katie Bocskor

With the commercialization of geocell soil confinement technology in the early 1980s, Presto Geosystems made history as one of the early pioneers in the world of geosynthetics. Over four decades later, that innovative spirit is as alive today as it was at the beginning of our journey. Presto Geosystems, the leader in geocell technology, announces the publication of the industry´s first Environmental Product Declaration (EPD) for geocells. This milestone reinforces Presto Geosystems’ ongoing commitment to reliable infrastructure and environmental quality.

What is an Environmental Product Declaration?

An EPD is a transparent, objective report that communicates what a product is made of and how it impacts the environment across its entire life cycle. The EPD, based on rigorous life cycle assessment (LCA) methodology, provides a comprehensive overview of the environmental impacts associated with the production, use, and disposal of Presto Geosystems’ GEOWEB® geocell system. This independent declaration includes key metrics such as carbon dioxide performance, energy consumption, and natural resource usage, all of which are vital factors influencing the overall environmental footprint of soil stabilization and erosion control solutions in civil and structural applications.

The EPD follows established international standards, including ISO 14025, lending to the credibility and consistency of the environmental data.

This initiative aligns with parent company Reynolds Consumer Product’s Sustainability commitments for Green Circle certification and efforts to improve documentation for environmental impact, and to reduce emissions, CO2e, and waste.

By providing detailed environmental impact information, Presto Geosystems is empowering engineers, consultants, architects, and project owners to make choices that align with their sustainability goals.

The EPD for the GEOWEB system is now available for download here >>

Patented GEOWEB Geocell System

Our patented GEOWEB Soil Stabilization System been installed on thousands of projects in every geographic region in the world and is the only geocell technology that has stood the test of time for over 40 years.

For more information, contact:
JP George, MS, CPESC-IT
Business Manager, Presto Geosystems
[email protected] | +1-920-475-7957

Building a Resilient U.S. Supply Chain for Critical Materials & Mining Infrastructure

Posted February 7, 2025 by Ashley Beyer

Written by: JP George, Business Manager

The U.S. Dept of Energy (DOE) classifies critical materials and minerals based on their importance to energy and supply risk. With the new U.S. administration taking office in January 2025, there has been a renewed effort to focus on strengthening the supply of these resources both domestically and abroad.

Strengthening Domestic Supply

Bipartisan efforts continue to bolster domestic mineral production through legislative actions, such as the proposed Critical Mineral Consistency Act of 2025 and revisions to the Energy Act of 2020. The National Mining Association (NMA) supports these measures, emphasizing the need for U.S. production over reliance on foreign sources.

According to the U.S. Geological Survey’s (USGS) 2025 Mineral Commodity Summaries, the U.S. remains import-reliant for many critical minerals, with China controlling production for over two-thirds of these resources. NMA President & CEO Rich Nolan states, “We could be producing most of these minerals here at home—under world-leading environmental, labor and safety standards”.

Projects like Perpetua Resources’ Idaho gold project could supply up to 35% of the U.S. annual demand for antimony, demonstrating the potential for revitalized domestic mining.

Innovations in Mining & Mineral Processing

Technological advancements are driving sustainable mining operations:

South32 Hermosa Project and the Battery Materials Development Grant are funding domestic manganese production for EV battery materials.
Argonne National Lab is developing methods to make more batteries with fewer materials, reducing reliance on foreign sources. Jeff Spangenberger from Argonne hopes to make “more efficient use of critical materials in domestic battery supply chains so that the U.S. can rely less on other countries to achieve its clean energy goals”.
The World Economic Forum’s Energy Transition Innovations report highlights groundbreaking technologies such as:
The Helios Cycle: A closed-loop sodium system that eliminates CO₂
Kofiln’s Exothermic Copper Processing: A method that significantly reduces SO₂

Innovative Soil Stabilization for Mining Operations

Beyond advancements in mineral extraction, innovations in soil stabilization are enhancing efficiency and safety in the mining industry. The GEOWEB geocells provide three-dimensional confinement and strengthening of infill, delivering:

increased speed of operation,
lower maintenance,
safer installation, and
a lower total cost of ownership.

Developed by Presto Geosystems, the original inventors of geocell technology, the GEOWEB geocells have been made in the USA for over 45 years. Their proven applications in the mining sector include:

Haul Roads & Site Access Roads – Providing stability over soft ground, both above and below grade.
Stormwater Containment & Channel Armoring – Controlling and containing runoff while protecting environmental barriers.
Geomembrane Protection – Reinforcing basins, tailings storage, and heap leach pads.
Mine Slope & Site Reclamation – Stabilization slopes for long-term restoration.

GEOWEB Geocells Proven Performance in Large-Scale Mining Applications

North Antelope Rochelle Mine (WY): The world’s largest coal mine by reserves relies on GEOWEB geocell-reinforced roads to withstand the demands of 400-ton payload ultra-class haul trucks. View project photos and case study >>
Western U.S. Evaporation Pond Access: Stabilized site access for operations over challenging terrain. View project photos and case study >>
Oxbow’s Elk Creek Mind (CO): Underground haul road stabilization using the GEOWEB geocells. View project photos and case study >>
Idaho Mine & Mill Site: Tailings stabilization and site reclamation for long-term environmental protection. View project photos and case study >>
Cyprus Miami Mine (AZ): Slope reclamation using GEOWEB geocells to secure disturbed land. View project photos and case study >>

Backed by Engineering & Research Excellence

As a leader in geocell technology, Presto Geosystems integrates over 40 years of accredited research and testing to ensure structural integrity and cost-effective solutions. Our in-house engineering team applies research findings to develop practical, real-world applications for the mining industry.

Get a Free Project Evaluation

Are you looking for a reliable, long-term stabilization solution for your mining operation? Our Free Project Evaluation service offers expert recommendations tailored to your specific needs.

How Geocells Provide Sustainable Solutions for Soil Stabilization and Erosion Control

Posted October 31, 2024 by Ashley Beyer

Innovative Site Solutions for Civil Engineering and Construction Projects

When faced with challenging site conditions—whether it’s weak soils, steep slopes, or erosion-prone channels—finding an efficient, long-term solution that minimizes maintenance is essential. Geocells offer just that. These innovative cellular confinement systems (CCS) are a proven solution for load support, retaining walls, slope stabilization, and channel protection applications. Geocells not only improve soil stability but also contribute to eco-friendly, sustainable project designs.

Geocells are three-dimensional, honeycomb-like structures typically made from high-density polyethylene (HDPE). By confining and reinforcing infill materials like soil/vegetation, sand, gravel or concrete, geocells create a stable, load-bearing surface. This cellular system prevents soil movement and erosion, making geocells a versatile solution for stabilizing weak soils and supporting structures such as roads, retaining walls, slopes, and channels.

How Geocells Work

The core function of geocells is to create a grid of interconnected cells that confine and stabilize infill materials. This CCS strengthens the underlying soil and distributes loads more evenly, preventing the movement of infill under pressure. In load support applications—such as roads, parking areas, or driveways—geocells act like a semi-rigid slab.

The geocell structure increases the load distribution angle and spreads vertical stresses over a larger area, which is commonly referred to as the mattress effect. This feature helps stabilize weak subgrades and prevents surface deformation, such as rutting or differential settlement, under heavy loads.

Key Benefits of Geocells

Soil Stabilization for Weak Subgrades: Geocells are designed to stabilize soils that would otherwise shift or settle under loading. By confining infill materials, geocells create a firm, stable base that can support the demands of roadways, heavy-duty parking lots, or other infrastructure projects. The mattress effect further enhances this stabilization, ensuring that vertical stresses are distributed across a wider area, reducing the likelihood of differential settlement or deformation over time.

Erosion Control for Slopes and Channels: On slopes and in channels prone to erosion, geocells help prevent soil from washing away during rainstorms or high-flow events. The cellular structure holds soil in place, creating long-term stability and reducing maintenance needs.
Sustainable and Eco-Friendly: By allowing the use of locally sourced infill, geocells reduce the need for imported materials and minimize the environmental footprint of a project. Their permeable design also promotes natural water infiltration, helping manage stormwater and reduce runoff.
Cost-Effective with Minimal Maintenance: Geocells are a cost-effective solution for stabilizing weak soils and preventing erosion. Their simple installation process and long-lasting performance mean reduced material costs upfront and less maintenance over time.

Common Applications for Geocells

Load Support: Geocells stabilize unpaved roads, parking areas, and other surfaces by evenly distributing loads, which prevents differential settlement and rutting.
Slope Stabilization: On steep embankments, geocells hold soil in place, reducing erosion while allowing vegetation to take root for natural reinforcement.
Retaining Walls: Geocells offer a flexible alternative to rigid retaining walls, adapting to natural shifts in the landscape and soft sub grade soils while maintaining soil retention.
Channel Protection: Geocells reinforce the bed and banks of stormwater channels, reducing erosion and ensuring long-term stability, even in high-flow conditions.

retaining wall slope channel and load support geocells

Introducing GEOWEB® Geocells: The Original Cellular Confinement System

While geocells are becoming widely used today, GEOWEB Geocells stand out as the original and most advanced system on the market. Presto Geosystems, in collaboration with the U.S. Army Corps of Engineers, pioneered the development of geocells in the late 1970s to address the need for reliable soil stabilization solutions in military and civil applications. This collaboration resulted in the invention of the GEOWEB system, which continues to lead the industry in performance and innovation over the past 40 years.

GEOWEB Geocells are made from high-quality, virgin HDPE, which offers superior strength, flexibility, and long-lasting durability compared to other systems. This ensures that the GEOWEB Geocells can withstand harsh elements and challenging conditions, whether it’s in load-bearing applications or erosion control projects.

The GEOWEB system is a complete geocell system, including ATRA® Accessories such as ATRA Connection Keys, ATRA Anchors, ATRA Tendon Clip, and the ATRA Driver. These components are designed to enhance installation efficiency and long-term performance, providing fast, secure connections that ensure the structural integrity of the entire system.

Comprehensive Construction Services, Engineering Support, and Free Project Evaluations

At Presto Geosystems, our commitment goes beyond providing high-quality products. We offer on-site field assistance, engineering support, and free project evaluations. Our team works with you at every stage, from initial project evaluation assistance to on-site installation support, helping you achieve the best results for your specific project challenges.

Understanding Hoop Stress and Wall Tension in Geocells

Posted September 9, 2024 by Katie Bocskor

Written By: Samantha Justice, P.E., Bryan Wedin, P.E.

Geocells provide one of the most powerful solutions available to engineers and contractors when designing and constructing roadways over soft and weak subgrades. With a successful track record of over 40 years, geocells have proven effective in load support applications over challenging conditions. If you’ve ever wondered how geocells work in load support applications – and the relationship between lateral confinement, hoop stress and wall tension – you’ve come to the right place.

Geocells are used to alter vertical stresses beneath an applied cyclical load. When a vertical, cyclical load is applied over geocells, active earth pressures develop in the loaded cell. These pressures arise due to the friction between the infill material and the cell wall. This friction pushes back against the passive earth pressure in the adjacent cells, helping to support the load. Refer to Figure 1. The balance of active and passive earth pressures activates the hoop stress in the cell walls, which increases the stiffness and bearing capacity of infill material. The infill material is confined within the individual cells with no chance of displacement, or lateral or vertical spreading and the result is increased stiffness. In effect, geocells behave more like three-dimensional structures or a semi-rigid slab by increasing the load distribution angle and spreading the vertical stresses over a larger area which is commonly referred to as the mattress effect.

Figure 1

An enhanced woven geotextile separation layer is typically provided under the geocell system and works in conjunction to provide additional load distribution along with filtration, separation, and controlled drainage. With the enhanced woven geotextile, it is possible to construct over extremely weak subgrades with standard penetration resistance (SPT-N) values less than 2 blows per foot (CBR < 0.5%), where planar geosynthetics, such as geogrids, would otherwise fail.

How Does Hoop Stress and Wall Tension Relate to Lateral Confinement?

Hoop stresses develop within the cell walls as earth pressures increase in response to an applied load at ground surface. In other words, the same earth pressures responsible for developing interface friction between the geocell and the infill material also result in hoop stresses with the cell walls. Although not perfectly cylindrical, geocells can be envisioned to behave similarly to an interconnected network of pressurized cylinders, wherein hoop stresses are a function of the net pressure that develops due to the internal and external pressures acting in and around each cell.
In this manner, radial pressures that develop within each cell are resisted by those that develop in the adjacent cells, and hoop stresses may be estimated using the classic equation for hoop stress for a pressurized thin-wall cylindrical vessel:

σ_H = p_net*(D/2t)

Where,

σ_H = hoop stress

p_net = net pressure = p_i – p_e

p_i = internal pressure

p_e = external pressure

D = geocell diameter

t = wall thickness

The active earth pressure in a loaded cell below a cyclical load can be calculated using the Boussinesq stress equation. The interaction between hoop stresses and passive earth resistance in geocell systems was investigated by Emersleben (2009) and observed that lateral pressures in adjacent cells decrease exponentially with increasing distance from the actively loaded, or “source” cell(s) – in effect, defining a pressure gradient. Based on Emersleben’s findings, it is possible to evaluate the net earth pressure that develops between the interior and the exterior of a cell wall, using the thickness of the cell wall as the distance between two points along the defined pressure gradient line. Refer to Figure 2.

Lateral Pressure vs Distance

Figure 2

The largest net earth pressures, and hoop stresses, occur in cells directly beneath the perimeter of the load footprint—the wheel contact area in the case of vehicle loads. Based on this, it is possible to estimate the maximum hoop stresses expected to develop in geocells in response to standard AASHTO load conditions.

Table 1 summarizes the estimated hoop stress and cell wall tensions developed under standard AASHTO load ratings for a 6-inch geocell-reinforced layer with a 2-inch wear surface. The calculated values assume a nominal 9.5-inch diameter geocell infilled with a granular material having an internal friction angle of 32 degrees and unit weight of 120 lbs/ft³.

Hoop Stress and Cell Wall Tension

AASHTO Load Rating	Wheel Load (lbs)	Tire Pressure (psi)	Hoop Stress (psi)	Cell Wall Tension (lbf)
AASHTO H/HS10	8,000	60	44	16
AASHTO H/HS15	12,000	85	63	23
AASHTO H/HS20	16,000	110	82	30
AASHTO H/HS25	20,000	125	96	34

Table 1

The corresponding tensile forces that develop under working load conditions are relatively modest due to the lateral confinement effect of the adjacent cells. When compared to the typical yield strength for most high-quality HDPE geocells, the above-referenced tensile forces are well within the elastic region for the material and any permanent deformation or “creep” over time is not expected, even when subject to cyclical traffic loads. Due to hoop stresses and earth pressures surrounding the loaded cells, there is no ability for the material to have any appreciable sustained deformation, and therefore, creep is not an issue.

The elastic response of the geocell-reinforced layer will ultimately be governed by the elastic properties of the infill material, and provided that suitable granular infill is used, the development of any significant strain in the cell walls will be heavily constrained by the effects of confinement of the granular material by the cell walls. The actual strain that develops in the cell wall will be significantly less than the amount of strain represented on a typical stress-strain curve generated from laboratory tests such as ISO 10319 or ASTM D4595 where samples are subjected to tensile forces in an unconfined state.

Development of hoop stress is essential for the proper engagement of the lateral confinement mechanism. Moreover, the ability to estimate hoop stresses under specific project circumstances can be useful as it allows engineers to develop a preliminary (and very conservative) understanding that tensile forces in the cell wall will remain within the elastic range for the material. It should be noted that many laboratory test methods such as ISO 10319 ignore the effects of confinement, and therefore, tend to overestimate strain levels that are outside of practical design conditions. Researchers who have completed laboratory and field test on geocells under applied loadings show that the strain in geocell walls is on the order of 0.2%. Evaluating material strength beyond reasonable strains is not relevant for sub grade reinforcement and the focus should be on strains less than 1.0%.

In general, provided the geocell is manufactured with a high-quality HDPE with a flexural storage modulus of at least 116 ksi (800 Mpa) and a 100-year durability rating (ISO 13438), the geocell can be expected to perform as intended throughout the service life of the project.

Using GEOWEB® Geocells in Landfill Capping Applications

Posted July 26, 2024 by Ashley Beyer

Written by: Cory Schneider, Business Development Manager

When contaminated material such as landfill waste or contaminated soil is encountered, there are typically two options available—removal of the material or placing a “cap” over it. In most cases, capping is the easier and more cost-effective of the two options. Caps serve to isolate the contaminated material, preventing people and wildlife from coming into contact with it.

Factors Influencing Landfill Cap Design

Landfill cap design for any particular site depends on many factors, including the type and quantity of contaminants, size of site, amount of rainfall, and future use of the area. It can consist of one or several of the following: asphalt or concrete, vegetative layer, drainage layer, and/or an impervious layer (geomembrane or compacted clay).

Preventing Slope Erosion with Advanced Geosynthetic Technology

close up of geocells infilled When using vegetative covers, especially in sloped areas, one of the best ways to prevent long-term erosion of the cap is to confine the topsoil component using geosynthetics like the GEOWEB Soil Stabilization System (geocells). The GEOWEB Geocells, which are three-dimensional ultrasonically welded strips of high-density polyethylene (HDPE), create small pockets to hold soil in place. By doing so, the system prevents erosion or sloughing when the soil becomes saturated, thereby maintaining the integrity of the cap.

Understanding Superfund Sites

Superfund sites are contaminated areas that require a long-term response to clean up hazardous material contaminations. The federal government designates these sites, and the Environmental Protection Agency (EPA) leads the remediation efforts to ensure public safety and environmental protection.

Case Study: 68^th Street Dump Superfund Site

One notable example of using the GEOWEB Geocells in a Superfund site is the 68^th Street Dump in Baltimore, MD. This project involved capping 51,000 square feet of landfill with slopes up to 60 feet high ranging from 3:1 to 1.5:1. Slopes flatter than 3:1 were deemed to not be at risk of significant erosion, and therefore, no geosynthetics were used on them. The solution effectively stabilized the topsoil, met EPA guidelines requiring a 12-inch cover, and ensured long-term erosion control and environmental safety.

Read the full case study: Superfund Site Landfill Capping | Presto Geosystems

North Carolina Pre-Regulatory Landfill Unit

In 2007, North Carolina established the Pre-Regulatory Landfill Unit within the Inactive Hazardous Sites Branch to address pre-1983 non-industrial landfills and dumps (any land area on which municipal solid waste disposal occurred before January 1, 1983). A tax of $2 per ton on municipal solid waste and construction and demolition debris was imposed to fund the program.

As part of the program, the team published a comprehensive document outlining Unit procedures for completing assessments and implementing remedial action plans. This document includes acceptable procedures and products for dealing with pre-regulatory landfills. Specifically, the document lists GEOWEB Geocells as an approved product for creating soil cover “caps” at these landfills.

Case Study: Franklinton County Landfill

Another example of the GEOWEB Geocells in action is the Franklinton County Landfill in North Carolina. This project involved installing 102,810 square feet of 4-inch GEOWEB GW30V (mid-sized geocell) over 8-ounce nonwoven geotextile fabric, filled with about 2,320 tons of structural fill and 2,500 tons of topsoil. The GEOWEB geocell panels were connected with ATRA® Keys and secured with Woven Polyester Tendons and ATRA® Tendon Clips.

Read the full case study: Franklinton Landfill Remediation Project | Presto Geosystems

Incorporating geosynthetics like the GEOWEB Geocells in landfill capping applications offers an effective solution for isolating contaminants, preventing erosion, and ensuring long-term environmental safety. These case studies demonstrate the practical benefits and successful implementations of these advanced materials in real-world scenarios.

Federal Railroad Administration (FRA) Announces $1.1 Billion Available in the Railroad Crossing Elimination (RCE) Grant Program

Posted July 15, 2024 by Katie Bocskor

The inaugural Railroad Crossing Elimination (RCE) grant program was designed to eliminate or improve roadway and railroad at-grade crossings, with the goal of making roads/rails safer while improving commute times for citizens.

According to the U.S. Department of Transportation website, “this program provides funding for highway-rail or pathway-rail grade crossing improvement projects that focus on improving the safety and mobility of people and goods.”

The grant program helps fund projects that involve:

repairing grade separations,
relocating tracks,
upgrading or improving protective devices, signals, or signs,
maintaining at-grade crossings, and more.

With safety as the top priority for the DOT, repairing and maintaining high-impact areas is critical so the potential for collisions or blockages can be prevented.

Applications for funding are due no later than 11:59 p.m. EST, September 23, 2024. Visit USDOT website for more information and to apply for funding >>

The GEOWEB® System stabilizes high-impact and crossing areas safely and quickly, limiting track downtime.

Areas subjected to heavy stresses at bridge approaches, diamonds, turn-outs, and crossings create the highest maintenance and safety liabilities for operations. The GEOWEB Soil Stabilization System (Geocells) is effective in reducing maintenance in these high impact areas.

The GEOWEB 3D Soil Confinement System has been successfully used by the railroad industry for over 40 years, helping to solve challenging soil stabilization problems for both new construction as well as railroad repair work. It is a proven and versatile ground improvement solution that is beneficial in soft soil environments and high-impact areas subjected to heavy stresses such as bridge approaches and crossings.

In at-grade crossing applications, the GEOWEB system is a three-dimensional geosynthetic that allows for the effective transfer of lateral earth pressures developed beneath applied loads to an interconnected network of honeycomb-like cells. As a result, stresses are reduced and distributed over a wider area through a phenomenon known as the mattress effect. The mattress effect reduces stress reaching the sub grade, and therefore, can mitigate the negative effects deflection and settlement.

For crossing applications, some of the key benefits of the GEOWEB System are identified below.

The 3D soil confinement technology creates a high-stiffness foundation under the track that reduces vertical stresses, allowing for a reduction of the subballast section up to 50%.
The GEOWEB System’s confinement reduces ballast compression and displacement leading to a more stable track surface requiring less maintenance.
The GEOWEB System limits upward movement of ballast particles and significantly increases stability of the track.
The system is quick to deploy and install, limiting track downtime.

Moreover, as summarized in Table 1, the GEOWEB Soil Confinement System can be used to improve high-impact areas that may be susceptible to settlement and long-term stability issues.

Table 1: GEOWEB Geocell Advantages for High-Impact Areas

High-Impact Area	Challenge	GEOWEB Geocell Advantage
At-Grade Crossings	Prone to stresses from aggressive rail loads and high-volume traffic	Dissipate stresses to control settlement and reduce maintenance/repair costs
Road Crossings	Excessive braking and acceleration forces transferred through the crossing to the subgrade	Dissipate forces from traffic and rail while delivering a floating platform that absorbs the braking and acceleration forces
Bridge Abutments	High-impact loadings and settlement	Dissipate stresses to control settlement and reduce maintenance/repair costs
Railroad Scales	Scales require a very stable subgrade for accurate measurement	Strengthen scale areas with the GEOWEB 3D system for extra stability and accuracy; especially over soft subgrades

The result is a more durable subgrade that increases railway life by preventing long-term settlement and consolidation. The ability to quickly install the GEOWEB panels and limit the track downtime is a critical factor in maintenance and safety operations for the rail industry.

Presto Geosystems offers a free project evaluation service to evaluate the unique needs of each project. Our recommendations will deliver a structurally sound, cost-effective solution based on four decades of accredited research and testing data. Submit your RCE project evaluation today and take advantage of the Grant Funding Program.

If you have questions about the RCE grant program, our project evaluation services, or need on-site support, please contact:

Bryan Wedin, P.E.
Chief Engineer
Presto Geosystem
[email protected]
(920) 791-0291

Energy Infrastructure and Climate Change: Protecting Erodible Slopes in Fire-Prone Areas

Posted June 28, 2024 by Katie Bocskor

Energy infrastructure is critical to the functioning of modern societies, and its protection against natural disasters and environmental threats is a top priority. Climate change exacerbates these disaster risks, with extreme weather conditions and wildfires being of particular concern, considering potential damage to the energy infrastructure and disruption of energy supply. Wildfires cause rapid, severe destruction, and, aside from damage to infrastructure, can impact our climate, vegetation, and atmosphere.

To measure the size and impact wildfires have, scientists use observations from several low Earth-orbit satellites, including the Copernicus Sentinel-3. These tracking satellites gather shortwave-infrared data combined with other techniques to differentiate between burned areas and other low reflectance covers such as clouds. The European Space Agency (ESA) compiles that long-term dataset to analyze global fire trends. According to the ESA, fire affects an estimated four million square kilometers (1.5 million square miles) of Earth´s land each year [1]. That is 400,000,000 hectares (990,000,000 acres) yearly—about half the size of the United States of America, an area larger than the country of India. The United Nations Environment Programme (UNEP) Rapid Response Assessment on Wildfires compiles findings from over 50 experts from research institutions, government agencies, and international organizations around the globe, and confirms that “wildfires are growing in intensity and spreading in range” with an “annualized economic burden for the United States to be between $71.1 billion and $347.8 billion USD” [2].

As wildfire seasons become longer and more extreme, the level of response must be increased. The United States and Canada have renewed an arrangement of cooperation to provide mutual aid during wildfire emergencies [3]. This, as Canada expects the 2023 wildfires, their worst on record, to continue into the winter season, with nearly 18 million hectares (44.5 million acres) burned to date through September 2023, as registered by the Canadian Wildland Fire Information System (CWFIS) [4].

In California, about 4.5 million hectares (11 million acres) have burned in wildfires over the past seven years, with an average of 485,623 hectares (1.2 million acres) per year [5]. The University of California´s Agriculture and Natural Resources (UCANR) Fire Network has studied post-incendiary erosion trends and offers a series of videos and other resources for wildfire and post-wildfire management. UCANR confirms the “chance for erosion is significantly greater and can result in mass movements of soil and water if vegetation has been burned off…with steep, hilly areas especially vulnerable” [6].

Project Case Study: Protecting Energy Infrastructure

The project owner had recently completed facility renovations and needed to repair and protect the slopes and hillsides surrounding the facility. However, the project owner had attempted other vegetated and non-vegetated erosion control methods in the past, and due to recent wildfires, drought cycles, and heavy erosion, those previous efforts did not achieve the desired level of long-term protection. The project owner and their contractor sought to meet initiatives from the U.S. Department of Agriculture (USDA) Forest Service for land management practices designed to mitigate erosion before and after severe fire events, and in evaluating possible solutions, the GEOWEB® Geocell Slope Protection System was identified for further evaluation and analysis. GEOWEB Geocells are three-dimensional cellular confinement products made from strips of high-density polyethylene (HDPE) welded together to create an expandable honeycomb-shaped structure. The geocells confine the soil or aggregate fill, minimizing movement and migration of the embankment materials by functioning as anchored containers in the upper soil layer. The geocell system resists sheet flow, preventing severe erosion and controlling rill and gully formation, especially in erosive post-incendiary soils.

Accordingly, the GEOWEB slope protection system was determined to have a high probability of achieving project objectives, and the facility owner ultimately selected the GEOWEB System utilizing tendon-based anchorage and ATRA® Tendon Clips (load transfer devices) in lieu of conventional staking techniques. The repair areas comprised two hillside areas of approximately 6,500 m2 (70,000 sf), with varying slope angles from 40-100°, and varying vertical heights from 6 m to 34 m (20 ft to 110 ft). After analysis of the site parameters, calculations for appropriate anchorage, planning for proximity to and around energy structures, it was determined that the 15 cm (6 in) GEOWEB Geocell with load transfer devices, integral connectors, high strength tendons, and earth anchors provided proper anchorage of the system without interference with existing infrastructure, as shown in Figure 1 below.

Fig. 1. Installation of tendoned GEOWEB Geocell System at energy facility.

The actual rock size chosen for the infill was based on slope angle and site hydraulic conditions, with earth anchor pullout strength determined by the Engineer of Record based on the manufacturer´s recommended factor of safety and site soil conditions. Aggregate infill was placed from crest to toe, using a rock slinger to assist workers and limiting the drop of the infill to prevent geocell wall distortion, as seen in Figure 2 below.

Fig. 2. A rock slinger helps workers place infill on steep slopes.

The tendon-anchored system with aggregate infill satisfied the needs of the project owner´s installation for long-term performance, burn protection, erosion control, and low maintenance while offering flexibility of fit without interference with the newly installed energy infrastructure.

GEOWEB Cellular Confinement System Options and Benefits

The GEOWEB Cellular Confinement Systems (CCS) offers a broad range of surface protection treatments for slopes that are subject to erosive forces. The inherent flexibility of the system, combined with a variety of adaptable anchoring techniques, permits the application of soft or hard armoring techniques to steep slopes. By ensuring the long-term stability and effectiveness of slope cover materials, underlying soils are protected, and customizable aesthetic objectives can be achieved. When slope reclamation and revegetation is desired, the geocell system provides the ability to fully vegetate slope surfaces that could not otherwise support plant life, with appropriate anchorage (based on specific site conditions) to hold the system to slope [7].

The GEOWEB walls, which contain the topsoil infill in a vegetated system, form a series of check-dams extending throughout the protected slope. Normal rill development, produced when concentrated flow cuts into the soil, is prevented since flow is continuously redirected to the surface. This mechanism also disrupts flow velocity and hence the erosive force of runoff. A predetermined depth of topsoil and the developing vegetative root mass is contained and protected within the individual cells. Roots become intertwined with the perforated cell walls, thereby creating an integrated, blanket reinforcement throughout the slope surface. In arid regions, it has been observed that the GEOWEB Geocells can enhance the development of indigenous vegetation by retaining a higher proportion of available moisture in the near-surface soil zone.

When vegetation is not appropriate or desired, aggregates or concrete infill may also be used for GEOWEB slope protection, stabilizing and protecting the surface. Aggregate infill reduces environmental impacts by allowing water infiltration on the slope face, reducing sheet flow runoff, and by precluding the need for irrigation systems, particularly in drought-prone areas, as might otherwise be required to maintain a vegetated slope cover. In this particular energy project installation, it was also chosen as a burn-protection zone around the newly installed energy infrastructure.

Protection of Energy Infrastructure Against Extreme Weather Events & Wildfires

The protection of energy infrastructure against extreme weather events and wildfires becomes increasingly more challenging as climate change exacerbates those threats. The National Park Service and the California Department of Forestry and Fire Protection (CAL FIRE) have started to collaborate with Indigenous communities to return traditional burning to the land as a wildfire prevention method [8]. Local tribes have helped to set prescribed burns in Yosemite National Park, among other wooded areas, as preventative protection against damaging wildfires like the Oak fire that burned over 8,000 hectares (20,000 acres) west of Yosemite National Park.

In addition to prescribed burns, erosion control solution sets must perform uniformly with a balance of properties for robust and resilient performance, as highlighted in the Overview of Resilience Concept by Bruneau et. al [9]. Resilience in infrastructure includes qualities that help reduce vulnerability, minimize the consequences of threats, accelerate response and recovery, and facilitate adaptation to disruptive events. All of these are likely to be expressed as essential for the solution sought in pre- and post-incendiary erosion control, especially for energy sector infrastructure.

Within the resilience framework, the concept of robustness presents unique opportunities for innovative solutions such as the high-quality GEOWEB Geocells to be integrated into infrastructure designs and contribute toward achieving infrastructure resilience goals. Redundancy to maintain functional requirements in disruption occurs with the use of aggregate infill, serving as both fire protection and a permeable hard-armoring stabilization of the slope. The resourcefulness of the GEOWEB Geocells with tendons and ATRA Tendon Clips with specific engineering values allows resources to be mobilized in an effective manner, without interference to existing energy structure. The rapidity in response of The GEOWEB Geocell System allows infill to be placed and the slope to be stabilized quickly, achieving project goals in a timely manner with reasonable labor and equipment inputs from contractors.

GEOWEB Geocells should be considered an industry best practice option for slope stabilization and a solution for pre- and post-incendiary erosion control on hilly, dry terrain prone to wildfire, drought, and erosion. The type of system as shown below in Figure 4 is an appropriate option for permanent and resilient erosion control at similar energy infrastructure sites around the world.

Fig. 4. Aggregate infill of geocell system at energy facility.

References

ESA, The European Space Agency, Counting wildfires across the globe, https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-3/Counting_wildfires_across_the_globe, accessed 02 Oct 2023, (2023)
UNEP, United Nations Environment Programme, Spreading like Wildfire – The Rising Threat of Extraordinary Landscape Fires. A UNEP Rapid Response Assessment. Nairobi. (2022). Full report available for download, https://www.unep.org/resources/report/spreading-wildfire-rising-threat-extraordinary-landscape-fires?gclid=Cj0KCQjw1OmoBhDXARIsAAAYGSEzkAlWAeRVeIplu-Z9UovZiWkWwq1NIa6RBs-RtScyBW5gOBOokbEaAumEEALw_wcB, accessed 02 Oct 2023.
S. Department of the Interior, Office of Wildland Fire, https://www.doi.gov/wildlandfire/canada-and-united-states-commit-enhanced-wildland-fire-cooperation, accessed 02 Oct 2023. (2023)
Canadian Wildland Fire Information System, CWFIS, National Wildland Fire Situation Report, https://cwfis.cfs.nrcan.gc.ca/report, accessed 02 Oct 2023, (2023)
CAL FIRE, Statistics on CA wildfires and fire activity, https://www.fire.ca.gov/our-impact/statistics, accessed 02 Oct 2023, (2023)
University of California, Agriculture and Natural Resources (UCANR), Fire in California – Erosion Control, https://ucanr.edu/sites/fire/Recovery/Revegetation/Erosion/, and Post-fire management, https://ucanr.edu/sites/fire/Recovery/Helpful_Presentations/, accessed 02 Oct 2023, (2023)
Presto Geosystems, GEOWEB Slope Protection System, Technical Overview, https://prestogeo.wpenginepowered.com/wp-content/uploads/2016/10/GWSL-Geoweb-slope-technical-overview.pdf, accessed 02 Oct 2023, (2018)
National Public Radio, A Northern California tribe works to protect traditions in a warming world, https://www.npr.org/2023/09/19/1199820474/california-fires-yosemite-indigenous-tribes-climate-change, accessed 02 Oct 2023, (2023)
Michel Bruneau and Andrei Reinhorn, Overview of the Resilience Concept, https://www.eng.buffalo.edu/~bruneau/8NCEE-Bruneau%20Reinhorn%20Resilience.pdf, accessed 02 Oct 2023, Proceedings of the 8^thS. National Conference on Earthquake Engineering, Paper 2040, (2006)

Transforming Transportation Infrastructure: Protecting Road and Bridge Embankments with Geocells

Posted June 11, 2024 by Ashley Beyer

workers installing geocells on highway slope

In a rapidly changing world, maintaining and improving our transportation infrastructure’s resilience and sustainability has become a critical concern for civil engineers. Climate change and increasing frequency of natural disasters present an ongoing challenge to the durability of our infrastructure. In the context of road and bridge embankments, protecting these structures can be of paramount significance to the safety and welfare of the public. These structures are often subjected to fluctuating environmental conditions, heavy traffic loads, and must be able to withstand major storm events to protect embankment materials from soil washouts and the long term damaging effects of erosion. So how can civil engineers meet these growing demands without compromising sustainability or longevity? Increasingly, engineers are turning to geosynthetic solutions, such as the GEOWEB® Soil Stabilization System—a low-maintenance and eco-friendly solution for long-term protection of road and bridge embankments.

In many cases, the GEOWEB Geocells offer a flexible, durable, and environmentally responsible alternative to traditional construction materials that can accommodate a wide range of infill materials, including soil, aggregate, or concrete, to establish hard or soft armor, as necessary, for protection as well as aesthetics. As we explore the capabilities of the GEOWEB Geocells, we will find that this solution not only addresses some of today’s most pressing infrastructure challenges but also paves the way toward a more resilient and sustainable future.

Improving Bridge Resilience with the GEOWEB Geocells at the I-90 Mississippi River Bridge

Bridge stability relies heavily on the long-term integrity of its abutments. Any vulnerability or weakness in these components can lead to structural failure with a potentially disastrous outcome. Therefore, prioritizing the design and construction of resilient abutments is crucial to ensure the stability and longevity of bridges.

In 2013, the I-90 Mississippi River Bridge, or the Dresbach Bridge, underwent a significant reconstruction project led by SRF Consultants. The aim was to replace the old bridge on the Wisconsin/Minnesota border and improve the interchange between Highway 61/14 and I-90 to enhance traffic safety and provide better access for motorists.

The GEOWEB System played a crucial role in two different applications. The GEOWEB sections (4-inch-depth, mid-sized cell) were utilized on slopes directly beneath the bridges and around structural supports, ranging from 2H:1V to 1.5H:1V, with heights up to 45 feet. These sections, filled with aggregate, were custom-produced in a tan color selected to blend in with the local aggregate color, improving visual aesthetics. Standard black GEOWEB sections (6-inch-depth, mid-sized cell) were used around the bridge abutments on slopes varying from 2.5H:1V to 3.5H:1V, reaching heights of up to 48 feet. These sections were filled with topsoil and covered with an erosion control blanket to support vegetation.

To secure the GEOWEB sections to the slopes, 18″ ATRA® Anchors were employed, with the anchor pattern adjusted to suit different slope characteristics, section depth, and infill material. The Presto Geosystems engineering team provided calculations and recommendations for anchor spacing in each of the 11 application areas.

The implementation of the GEOWEB Soil Stabilization System in the Dresbach Bridge project was completed in the fall of 2016. This versatile system continues to provide robust slope protection, offering benefits for both aesthetics and long term project resilience. The Dresbach Bridge project serves as a testament to the versatility and effectiveness of the GEOWEB System in achieving slope stabilization and erosion control objectives around a vital piece of U.S. transportation infrastructure.

Fortifying the Roadway Embankment along River Road in Lewiston, Maine

Roadway embankments are another critical component of transportation infrastructure that face similar challenges. Erosion, washouts, and landslides can all lead to road failure, posing significant safety risks and disruptive repair costs. To protect against these risks, the GEOWEB Soil Stabilization System adds a valuable layer of protection. The three-dimensional honeycomb-like structure confines infill materials and protects slopes from sheet flow runoff, washouts, and shallow translational failures that can occur during and following major storm events.

River Road in Lewiston, Maine, faced a similar challenge due to its steep 1:1 slope and heavy traffic, including constant truck flow. To ensure the long-term safety and integrity of the road, the River Road Reconstruction project was initiated, which included pavement reconstruction, shoulder widening, and construction of a stabilized vegetated slope, among other upgrades.

before and after installing geoweb geocells vegetation

One significant hurdle was constructing a 45-degree vegetated slope, with the risk of erosion heightened during spring seasons due to rainfall and snowmelt. To maintain the slope’s stability and the road’s integrity, the GEOWEB Vegetated Slope Protection System was chosen for soil stabilization and erosion control.

The system’s installation process utilized geogrid lifts for enhanced slope stabilization. The 3D cellular GEOWEB system, combined with a tendon system, held the topsoil in place on the steep slope, enabling sustainable vegetation growth and mitigating severe erosion risk.

The GEOWEB system was filled with rocks at the slope’s toe for a strong foundation, with larger rocks on top for added support. Moving upwards, cells were filled with topsoil and covered with a turf reinforcement mat to promote grass growth, demonstrating the pivotal role of the GEOWEB geocells in providing stability, soil confinement, and vegetation support.

A Step Forward in Sustainable Infrastructure

In the face of modern infrastructure challenges, civil engineers need solutions that are not only resilient but also sustainable. GEOWEB Geocells provide a dynamic response to these demands. They offer significant benefits in terms of durability, adaptability, and environmental consciousness, making them an optimal choice for modern bridge and roadway embankment projects.

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