Lewiston, Idaho

The Team
  • 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.

    • Transportation Design
    • Water and Wastewater Engineering
    • Grant Writing and Administration
    • Civil Engineering
    • Structural Engineering
    • Environmental Engineering
    • Geotechnical Engineering
    • Surveying
    • Construction Management and Inspection
    • Public Involvement
    • Graphic Design, Website Development, Photography/Video Production
  • TD&H Engineering
    Lewiston Regional Office

    210 Main St
    Lewiston, Idaho 83501
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    Monday – Friday 8:00am – 5:00pm

    Phone (208) 746-0938
    Fax (208) 746-9732

    Email Us

  • David Witthaus, P. E. & Principal
    Vice President/Regional Manager

    David was hired in 1993 to open the TD&H Lewiston office and has been in the Lewis-Clark valley since 1994. He is a firm Principal and a Senior Transportation Engineer, overseeing roadway and highway design projects and all regulatory compliance issues typically associated with federal-aid work. David excels in assisting clients with Public Involvement programs that foster positive community and stakeholder input, leading toward successful completion. He has a B.S. in Civil Engineering from Walla Walla University.

    Heather Calkins, P. E.
    Engineer - Civil

    Heather is a LC-Valley native and an Asotin Panther to the core. She has been a major part of TD&H’s Lewiston operation since 1997 and is our lead Civil Designer. Heather excels in the design of site grading plans, drainage systems including on-site detention, utility design, and preparation of Storm Water Pollution Prevention Plans, and has completed literally hundreds of land development projects while at TD&H. She’s accredited through the EPA as an asbestos inspector and is an ITD-certified C.A. Inspector.

    Krista Brown, P.E.
    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.

    Michelle Bly, P.C.E.D. & Principal
    Marketing & Funding

    Michelle has 18 years of experience in community and economic development, specializing in project development and financial assistance through grant/loan writing, administration, and environmental compliance. She is a Professional Community and Economic Developer (PCED) and a Certified Grant Administrator. Michelle has a B.A. in Business from Lewis-Clark State College and a Masters of Science in Community and Economic Development from University of Central Arkansas. Michelle spends most of her time on the road meeting with clients, overseeing construction compliance, and working with funding agencies to find communities funds for their projects.

    Mark Weigand, P. L. S.
    Professional Land Surveyor

    Mark has served as our local survey manager since 2001. His role in projects includes leading the design survey team and providing construction staking when the project gets to the construction phase. Mark is an Idaho and Washington Registered Land Surveyor and Party Chief, and has been involved in almost every TD&H project. He understands what is required to provide the necessary information for an accurate design, and is highly-detailed during construction staking to ensure a quality project.

    He received his A.A.S. in Drafting Technology from Lewis Clark State College.

    Jennifer Blood, E.I.T.
    Civil Engineer and Inspector

    Jen has a Bachelor of Science in Civil Engineering and provides technical writing for Preliminary Engineering Reports and engineering design and support for a wide variety of projects including sidewalks, roadways, water reservoirs, and water distribution systems .Jen’s strength is construction management and is detailed oriented. Jen owned her own construction company prior to getting her engineering degree, which brings a unique “constructability” perspective to projects.

    Gwen Ellis, E.I.T.
    Civil Engineer and Inspector

    Gwen has a Bachelor of Science in Civil Engineering and Master of Science in Mechanical Engineering. Gwen’s background in both civil and mechanical applications makes her uniquely-suited to assess, troubleshoot, plan, design and inspect mechanical systems that is extremely beneficial to water and wastewater projects. Gwen provides technical writing for Preliminary Engineering Reports and Water System Plans and engineering design and support for a wide variety of projects including sidewalks, roadways, water reservoirs and water distribution systems. Prior to joining TD&H Gwen worked for a consulting firm where she assisted in various wastewater projects, including membrane filtration, odor control upgrades, and plant start-up. Gwen also assisted with bridge inspections for the Montana Department of Transportation.

    Jenni Light, M.S., PhD
    Engineer - Environmental

    Jenni has over 20 years of environmental experience working with municipalities, government agencies and industry. Jenni has experience in environmental permitting, (air, water, solid and hazardous waste), SPCC plans, stormwater and erosion control plans, environmental assessments and audits including SEPA as well as GIS mapping in addition to teaching engineering at our local college.