What Waits Below? Taming the Risk

Nobody likes a surprise in development, especially during construction. Urban Site development and excavation for foundations and utilities often encounters material referred to as urban fill or historic fill . This material originates from commercial, industrial and manufacturing uses dating back to the nineteenth century. Urban fill is also found at waterfront locations where land has been created or raised. Suburban land is not immune, occasionally being the recipient of fill from nearby urban activities. Identification, characterization and management of urban fill risk is a prudent element of pre-purchase and development planning. Isn’t it better to factor such contingencies into the purchase price?

While urban fill may contain macroscopic evidence of its non-native origin (brick, concrete, glass, ceramic, metal, etc.), just as often it may not appear significantly different from native soil. Only upon close inspection by a qualified professional, will subtle evidence of asphalt fragments, incinerator ash, coal and coal ash, slag or dredge material become apparent. Often, chemical analyses of fill result in detection of poly-nuclear aromatic hydrocarbons (PAHs), heavy metals (lead, arsenic, chromium, etc.), PCBs and pesticides, at concentrations which exceed regulatory criteria. “Polluted” urban fill may also pose risks for persons potentially exposed to the soil during or after construction.

Ownership and development of properties containing urban fill involves appropriate management in compliance with regulatory guidelines. Polluted urban fill generally requires management under solid waste regulations unless the site is already in a remedial program.

Often however, the status, requirements and reuse potential of urban fill vary and are not always well-defined by the regulations. Consider that regulatory definitions exist in NY and CT, for urban soil, historic fill material, clean fill, polluted fill, general fill, restricted-use fill, limited-use fill, and polluted soil, each with their own connotations

We understand the presence of fill can have significant financial implications for development. Onsite reuse options exist and are usually preferable. Off-site disposal alternatives for surplus or unsuitable polluted fill depend on chemical analyses and associated expense.

What to do?

Advance planning can mitigate the potential for unexpected remediation, construction delays, premium costs, business interruption and liability exposure.

The best approach is to begin environmental site characterization pre-purchase. Also, combining environmental and geotechnical assessments can be cost effective. We can assist you in navigating these regulatory waters with a focus on your goal – a successful project.

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