TD&H started the Lewiston office in 1994. Over the last 21 years, we have grown from four people to a full-time professional staff of 16, including three registered professional engineers, a certified grant administrator, professional geologist, registered land surveyor and dedicated support staff.

Historically, the Lewiston office has been very strong in transportation work, designing miles of roadways, highways and bridges for the Idaho Transportation Department and cities and counties within both Washington and Montana. Surveying has also been part of the backbone of our operation, and our full-time survey crew are experts in all types of boundary, topographic and construction surveying.

In July of 2012, TD&H merged with Progressive Engineering Group. We are excited to now offer expertise in water and wastewater system design. In addition, we are now the only regional engineering firm that offers both top-notch design services and certified grant administration.

Our local construction division provides in-house expertise in heavy construction as well as materials and compaction testing.

Monday - Friday, 8:00am - 5:00pm

(208) 746-0838

Fax: (208) 746-9732

Send us an email


Project Highlight: Stites Water System Improvements

The City of Stites is currently in construction of water system improvements, which includes a 174,000 gallon, 30-foot diameter, 34-foot tall prefabricated bolted steel plate fusion bond coated steel tank to be erected onsite. The remaining improvements for the project include replacement of 7,000 LF of water main, replacement of 119 water meters, installation of…



Recent Projects

Pomeroy 6th Street Bridge

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Stites Wastewater System Improvements

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Sunnyside Reservoir, Pump Station & Waterline Relocation and Replacement

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University of Idaho Tunnel Lid

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Meet the Team

Michelle Bly P.C.E.D., A.I.C.P. & Principal

Vice President/Regional Manager

Michelle is a Professional Community and Economic Developer, Certified Planner, and Certified Grant Administrator. Her experience includes 24 years of working with municipalities on water and wastewater, transportation, and environmental documentation projects. She also provides municipalities assistance with grant/loan funding, planning documents, construction administration, public involvement, and client advocacy.


Krista Brown P.E., PhD

Engineer - Structural

Kris has worked on hundreds of industrial, commercial, military, and residential new construction and renovation projects.  Kris has over 30 years of experience in structural design, analysis, and construction.  Prior to joining TD&H, Kris focused on precast and prestressed concrete structures including pedestrian and vehicle bridges, industrial, commercial, agricultural, water storage and treatment, and detention facilities.  She has experience in project management and design/build projects.  She is familiar with current codes such as ACI 318, ASCE 7-10, IBC 2012, and AASHTO Bridge Design Specifications.

Kris received her B.S. in Civil Engineering from Iowa State University, M.S. in Soils Engineering from Iowa State University and PhD in Civil Engineering from University of Idaho.


Alfred Sanchez, III P.E.

Engineer - Structural

Alfred has experience in the structural design, analysis, project management and construction of structures using steel, concrete, masonry, cold formed steel and timber. Alfred has worked on military, educational, commercial, residential and industrial jobs primarily in building structures. Alfred received his BBA in financial management from the University of New Mexico and MS in Civil Engineering from the University of New Mexico.


Jenni Light PhD

Environmental Engineer

Jenni has over 27 years of engineering experience and has worked extensively with municipalities, government agencies, and industry. Her expertise includes environmental permitting, (air, water, solid and hazardous waste), SPCC plans, stormwater and erosion control plans, environmental assessments and audits, emissions inventories as well as GIS mapping and modeling.


Morgan Porter E.I.

Design Engineer

Morgan is an Engineering Intern who assists the Lewiston office at various levels. She is trained in a variety of engineering software, including AutoCAD, ArcGIS, Revit, and more. Morgan is a graduate of Washington State University, and provides engineering design and support for a variety of projects, especially wastewater and infrastructure projects. She assists with technical writing for Preliminary Engineering Reports and has performed inspection duties for a variety of municipalities.


John McMahan P.L.S.

Land Surveyor

John is a registered professional land surveyor in Colorado and is currently working towards licensure in Idaho and Washington. John has over 35 years of experience as a land surveyor and is proficient in all types of surveying techniques including conventional and GPS survey equipment systems and provides both office and field support.


Benita Welin

Engineer Technician

Benita earned her degree in Engineering Tech with studies in Civil, Structural, Architectural and Mechanical Engineering. While attending school, she worked with Professional Surveyors performing surveying related work, collecting field data, and working with ArcPro and ArcMaps to create maps and charts for the Lewis and Clark Valley MPO to interpret road and parking improvements.


Mary Iacobelli

Administrative Assistant

Mary brings nearly 20 years of experience in writing and office management to the team. In the past, she has been a newspaper reporter, public relations writer, transcriptionist and office manager. She earned a degree in Journalism from Oakland University.



Project Highlight: Stites Water System Improvements

June 3, 2022

The City of Stites is currently in construction of water system improvements, which includes a 174,000 gallon, 30-foot diameter, 34-foot…


Welcome New Great Falls Staff!

May 13, 2022

Please join us in welcoming Doug Wilmot, PE and Amanda Carlson, EI to the Great Falls office staff. Amanda will…


Project Spotlight: Bridge & 14th Streets Site Development

December 2, 2021

Location: Clarkston, WA This multi-use development includes a hotel, commercial storage unit complex, and multiple duplex residential development. Due to…