Maryland Section Event | Ellicott City North Tunnel – A Unique Perspective on the Design & Construc

When:  Nov 12, 2025 from 05:00 PM to 09:00 PM (ET)
Associated with  Maryland Section

Registration is now closed. We can no longer accommodate any new registrations.

Ellicott City North Tunnel

A Unique Perspective on the Design & Construction of a Stormwater Diversion Tunnel

Speakers: Chris Nelsen, PE, ENV SP; Andy McLean, PE, CFM; Zach Hollenbeck

ABOUT THE PRESENTATION

The Ellicott City North Tunnel is a cornerstone of Howard County’s Safe and Sound Plan for Ellicott City.  The roughly 1-mile long, 18’ diameter tunnel began construction in 2024. When complete, the tunnel will divert stormwater from high flow storm events in the Tiber-Hudson River around Ellicott City to mitigate flooding. This presentation provides a detailed look at the tunnel from a runoff perspective, following a raindrop in the watershed headwaters through the North Tunnel diversion structures and various tunnel features. Along the way, the audience will gain an understanding of unique tunnel design elements, their function, and ongoing construction efforts.
MEET YOUR SPEAKERS
Chris Nelsen, PE, ENV SP serves as the Resident Project Representative for Howard County on the Ellicott City North Tunnel project. He is a Senior Project Engineer at Delve Underground with 7 years of geotechnical engineering experience. Beyond geotech, Chris is engaged in industry-wide efforts to improve sustainability of infrastructure projects through the ISI framework as an Envision Sustainable Professional (ENV SP) and in the redevelopment of the EFFC-DFI Carbon Calculator. Chris holds a BS in Civil Engineering from Lafayette College and an MS in Geotechnical Engineering from the University of Texas, Austin. He is a registered Professional Engineer in Maryland.
Andy McLean, PE, CFM 
is a Senior Project Manager with over a decade of experience engineering a variety of water resources projects in the mid-Atlantic area. His experience has ranged from drainage and stormwater design in support of transportation projects, to managing design and construction retrofits of high-hazard stormwater management facilities. McLean has specialized in hydraulic modeling to support complex flood mitigation studies and managing mitigation projects, from design through implementation. The keynote project in his career has been supporting various tasks associated with Howard County’s Safe and Sound Flood Mitigation Plan for Ellicott City.  Andy is Professional Engineer and an ASFPM Certified Floodplain Manager (CFM) and serves as current vice chair for the Maryland Association of Floodplain and Stormwater Managers (MAFSM).
(Robert) Zach Hollenbeck 
is Howard County’s Project Manager for the Ellicott City North Tunnel, ($168M) a key component of the EC Safe and Sound Flood Mitigation Plan. Since joining the County in 2018, Zach has worked as a Project Manager and Deputy Chief of the Bureau of Facilities in the Department of Public Works. Over a nearly 20 year career as a registered Architect, Zach has worked on a variety of mission critical, continuity of operations, and historic renovation projects. A graduate of the Catholic University of America’s School of Architecture and Planning, Zach resides in Historic Ellicott City with his wife, son, dog, and too many tractors to count.
Please note the updated pricing!
Timeline:
6-7 PM: Cocktail / Networking Hour
7-7:45 PM: Dinner
7:45-9 PM: PDH Presentation
More information

Location

The Engineer's Club - Garrett Jacobs Mansion
11 W. Mt. Vernon Place
Baltimore, MD 21201

Pricing Information

Registration Price
Student $35.00
Member $55.00
Non-member $65.00
Staff Class $40.00
Speaker Free
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