• People. Focused. Future.

    When we all need to think of the long-term environmental outcomes for future generations, Verdantas is driven simply by one passion – To help build a better world.
  • Hull & Associates is now Verdantas

    Peer recognized excellence brought to Verdantas from Hull with strengths in the environment, energy, and infrastructure markets.

  • Duffield Associates is now Verdantas

    Diverse services in civil, environmental engineering, geotechnical engineering, water/wastewater engineering, and materials testing added to Verdantas capabilities.

  • HSW Consulting is now Verdantas

    Offering a proactive, programmatic view of environmental assessment and remediation, waste and resource management, environmental protection and cleanup, as well as regulatory partnering to the Verdantas capabilities. 

  • GeoInsight is now Verdantas

    Bringing focus to navigating the complexities of environmental and engineering projects and the intricacies of applicable regulations to help Verdantas’ clients meet their project goals.

  • Alden is now part of Verdantas

    The oldest continuously operating hydraulic lab in North America

    127 years of history of high-end Computational Fluid Dynamics (CFD) and fluid flow modeling, best in class physical modeling, field measurements and precision flow meter calibrations with extensive experience in the modeling and permitting of hydroelectric dams, nuclear facilities and coastal and riverine modeling and environmental compliance projects.

A commitment from our leadership team

Let’s make a better tomorrow

From Gerry Salontai, PE
CEO, Verdantas

I have the great pleasure of introducing you to Verdantas – whose singular mission is to create a better world for ourselves and future generations. Verdantas was created by merging 5 companies – Alden Research Laboratory, Duffield Associates, GeoInsight, HSW Consulting and Hull & Associates into One Great Company. Led by a group of engineers, planners, scientists, and technology experts with shared values, cultures and...

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Combined Years in Business


States with PE & PG Licensure



Our capabilities

Recent Experiences

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The City of Philadelphia was more progressive than most older northeastern cities when addressing confined sewer overflow issues that are typical of aging and outdated underground infrastructures. Instead of the usual downgradient treatment plants, they decided to capture and infiltrate rainwater near the source, thereby mitigating flows into the already full sewers which were leaking into their streams and rivers. Such an undertaking relies not only on one big project, but on a multitude of smaller successes. Verdantas has been working with the City for over a decade, initially in reviewing private sector plans for upgrading detention and infiltration opportunities, to working with the City for the identification and design of City projects for the same purpose.

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Sustainability | Civil Infrastructure
PWD Green Stormwater Infrastructure Design

Green stormwater infrastructure design for the City of Philadelphia Water Department

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Alden was retained by the Northern Water Conservancy District (Northern Water) for the Hansen Supply Canal Poudre River Drop Structure Replacement Project. Alden was the prime consultant for the Project and provided complete structural and hydraulic engineering services, including hydraulic modeling for the design of the replacement drop structure and overall site improvements. The new structure included a stepped spillway, stilling basin, and retaining walls.

Alden performed Computational Fluid Dynamics (CFD) modeling of the existing structure and the proposed structure. The new structure is designed for a peak discharge of 1,500 cfs. Alden also performed 3D finite element modeling for the structural design. Alden collaborated with Northern Water staff to identify maintenance needs and preferences for the new structure. The stilling basin includes an access bridge, jib cranes, and stoplogs to isolate the structure for future maintenance and inspections. The existing site featured extremely steep slopes at 1V:1H with poor surface drainage. The final grading established stable slopes and improved surface drainage to keep water away from the new structure.

Details of the project included:

  • Concrete structure demolition, removal, and repair
  • New concrete stepped spillway, concrete stilling basin, and concrete retaining walls
  • Foot bridge with access stairs
  • Subsurface drain system and surface drainage improvements
  • Temporary construction cofferdam and dewatering
  • Site grading and access road
  • Trapezoidal channel restoration and riprap sizing

The project also required coordination regarding the environmental impacts to the Preble's mouse habitat and an adjacent eagle's nest. Design was completed in July 2019. Construction was completed in March 2020 with the first water flowing through the structure on April 1, 2020. 

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2020 H2O Project Award

The Poudre River Drop Structure Project was the recipient of The Colorado Contractors Association's 4th Annual H2O Awards. The Project won in the category of Open Concrete Flow Structures under $6 million. 

The overall Project Team included: 

  • Design Team – Alden and geotechnical subconsultant, Lithos Engineering
  • Client – Northern Water 
  • Contractor - Zak Dirt
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Civil Infrastructure
Poudre River Drop Structure Replacement

Alden provided structural and hydraulic engineering and CFD modeling to replace the Poudre River drop structure with a stepped spillway and stilling basin.

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Dam Remediation Using High and Low Mobility Pressure Grouting

Logan Martin Dam, owned and operated by Alabama Power Company, is a hydroelectric generation site located on the Coosa River in Vincent, Alabama. Since construction in the late 1960’s, ongoing remedial pressure grouting projects have targeted significant seepage flow reduction beneath the embankment dam which is founded on karst, a limestone geology characterized by underground aquifers, caverns, and the potential for sinkholes, particularly as seepage flow erodes the underlying limestone and continually changes its distribution. Alden and Alabama Power have partnered to design and construct a large scale enclosed pressure grouting test chamber (3’ wide by 3’ tall by 30’ long) and an associated test protocol to evaluate and optimize grout mix design performance in geo-materials that simulate the fractured, cavernous geology at Logan Martin Dam.

This first-of-a-kind test approach uses a small production scale grout plant to prepare and inject the high mobility grout mixtures into the test chamber. The test chamber is designed with discharge ports along its length to allow water initially occupying the test chamber—and subsequently grout—to be displaced as newly batched grout is injected. Throughout the grout injection process, pressure and temperature measurements within the test chamber, as well as discharge flow rate and discharge flow specific gravity measurements out of the test chamber, are used to monitor and evaluate grout dispersion characteristics within the chamber.  

Grout injection criteria used to govern test advancement and later termination includes displaced grout quality (i.e., displaced grout specific gravity relative to that of the freshly batched grout) and the internal test chamber pressure. After grout injection, various performance metrics are evaluated to quantify mix effectiveness. The normalized grout take, for example, evaluates the overall mix efficiency by relating the injected grout volume to the volume available within the geo-material for grout to occupy.

Since conception, updates to the test facility and protocol have been made to facilitate low mobility grout testing, as well as grout performance testing in the presence of water cross flow. Results from this ongoing research program are being used to reduce grouting cost through grout mix design and bore hole spacing optimization, while also improving dam safety by increasing knowledge on how grout penetrates rock fractures without in-situ excavation.

Contact us if you would like to learn more.

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Civil Infrastructure
Grout Performance Testing – Logan Martin Dam

An innovative large scale enclosed pressure grouting test chamber is being used to evaluate and optimize grout mix design performance at Logan Martin Dam


New Additions Expand Landscape Architecture Capabilities
New Additions Expand Landscape Architecture Capabilities

The Verdantas platform of companies is excited to announce the addition of Matthew Spong, RLA, ASLA and Trisha Sawicki, ...

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