Photo by Retail Personnel

Solution
Retail Space

Photo by Retail Personnel

Retail Space

Photo courtesy of PS Doors

Retail Space

In the summer of 2014, a high-intensity rainfall in Cambridge surcharged the city’s stormwater drainage system, resulting in localized flooding near a basement-level retail space. The floodwaters overtopped the sidewalk and flowed down the entryway stairs, inundating the retail space and causing significant damage. SGH investigated the circumstances surrounding the damaging flood event and developed a strategy for mitigating future flooding.

Scope | Solutions

Our investigation included the following:

  • Analyzing local rainfall data to quantify the return period of the storm

  • Coordinating an elevation survey of the building exterior, as well as an elevation survey and inspection of the stormwater drainage system within the local watershed

  • Performing a hydrologic and hydraulic analysis of the city’s stormwater drainage system to estimate flood elevations for select rainfall events

  • Determining the probability of repeat flooding

  • Developing conceptual strategies to prevent future flooding

SGH coordinated with the owner to determine their goals and designed a flood mitigation strategy considering a 100-year design flood elevation plus 4 in. of freeboard. Highlights of our design include the following:

  • Flood barriers that automatically raise into place when floodwater reaches an entrance below the design flood elevation, allowing for immediate deployment without human intervention

  • Raised concrete curbs at window wells around the perimeter of the building

  • New waterproofing behind the existing brick veneer and on new concrete walls and floor surfaces

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