February 8, 2018 | by James Sines

Sometimes design specifications must be altered after construction begins because environmental condition assumptions made during the design phase have changed unexpectedly. What’s the general contractor to do? The general contractor’s initial reaction to a change in conditions may be to:

  • Stop construction activities.
  • Diagnose the situation internally.
  • Wait for the owner’s directive.

Each of the above reactions comes with a risk of wasted time and money. How the general contractor handles these changes can make the difference between massive delays or timely completion of a multimillion-dollar construction project. Innovation is often needed to move construction forward and maintain regulatory compliance.

A Groundwater Challenge

EBA recently addressed a change in baseline conditions for a sanitary sewer rehabilitation that involved installing a mile of sanitary sewer piping using micro-tunneling, hand mining, and open-cut methods. In the original design specifications, groundwater from dewatering operations during construction was to be discharged into the existing sanitary sewer system. Unfortunately, the receiving wastewater treatment plant refused to accept groundwater from the dewatering activities.  

While groundwater was accumulating in the completed shafts, a new disposal solution was urgently needed. The collection, transport, and off-site disposal of groundwater was too expensive, since so much groundwater was being generated during dewatering activities. The solution would also have to accommodate conditions at each individual shaft location and for the construction project as a whole while complying with regulations.

To tackle this challenge, EBA evaluated the laboratory data and conditions at each shaft location and developed an alternate approach to dispose of the groundwater into the City’s municipal separate stormwater sewer system (MS4).

To get approval for the new approach, we launched a multifront effort that included multiple communications with regulatory officials, collection and analysis of groundwater for specific contaminants, review of permits and standards, numerous internal department meetings, and drafting of a discharge permit application that included provisions for treatment of groundwater prior to discharge into the MS4.

The Agency approved EBA’s proposed treatment system, and within 7 calendar days, the contractor received their formal approval for discharging the groundwater into the MS4. To date, EBA has secured five distinct discharge permits for the project without any delay in construction activities.

Unfortunately, changes and alterations to even the best laid plans are a reality on any construction project. But sometimes all it takes is a bit of innovation and “thinking outside of the box” to find a solution that keeps the project on track.

James Sines is the environmental engineering department manager at EBA Engineering, Inc. He can be reached at 410.504.6112 or james.sines@ebaengineering.com.

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