Ellicott City Watershed Master Plan

Ellicott City, Maryland

Mahan Rykiel is currently working with Howard County, Maryland, leading a team of professionals in the development of a master plan for Ellicott City and its watershed. Ellicott City is an historic community, located at the confluence of multiple tributaries that feed into the Patapsco River. The community is steeped in history, including its location along the National Road, the first terminus of the original B&O Railroad line and rich mill history dating back to 1772.

The stakeholder-based planning effort began in May 2017 in response to a devastating flash flood in July, 2016. While flood mitigation, grounded in Hydrologic and Hydraulic Analysis, has always been the foundation for the planning effort, the master plan is far more encompassing, addressing flood mitigation as it relates to achieving the community’s vision as a model resilient community that thrives by protecting its people, commerce, history, culture and natural environment.  To that end, the master planning team has been developing recommendations that address a broad range of inter-related flood mitigation, urban design, transportation, historic preservation, economic development, community marketing and organizational challenges that could be addressed in the short, medium and long-terms, spanning up to 30 years. 

The planning was underway for approximately one year and nearing completion when a second, even more devastating, flash flood occurred in May 2018, placing a new sense of urgency on immediate action. In response, Howard County developed a “5-Year Strategy” to implement flood mitigation measures that would make the most impact in a short period of time, with emphasis on life safety. As a result, the County has had to make difficult decisions, including the planned removal of several historic buildings along lower Main Street to allow widening of the channel and more effective conveyance of floodwaters.

While many of the Mahan Rykiel team’s recommendations remain relevant following the second flood, the master plan effort has evolved to include helping the County envision how the widened channel along lower Main Street could also serve as an attractive, vibrant open space within the heart of the community. As with addressing most challenges in Ellicott City, this effort includes a complex set of inter-related challenges, including the careful balance of maximizing hydraulic function and creating a useful and attractive amenity space while being sensitive to the community’s rich history and the interpretation of the buildings lost.