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Jan. 25, 2018

Environmental remediation for urban infill projects

Infill projects ( as opposed to "greenfields") come with added issues, namely environmental contamination.

By Chris Spengler
As San Diego continually faces a housing shortage, ever increasing traffic congestion, and escalating construction costs, the answer always seems to be higher density in already developed areas, otherwise known as "urban infill." However, working on infill projects as opposed to "greenfields" (otherwise previously undeveloped land) comes with added issues, namely environmental contamination.

This contamination ranges from petroleum products (gasoline, diesel, oil) from leaking underground storage tanks and pipelines, solvents from industrial and automotive industries and from dry cleaners, to heavy (toxic) metals such as lead, arsenic, chromium, etc., to burn ash that contains heavy metals, carcinogens and dioxins.

There are three major issues with these contaminants that must be addressed:

  • Do they pose a health risk to humans at the property?

  • Do they pose a risk to the environment?

  • Proper handling, management, and disposal of contaminated soil and/or groundwater.

Given this daunting task, one would think that it is common practice for developers to expend considerable resources to understand the extent of contamination and in planning to address it before or during construction.

What's that they say? "Poor planning on your part does not necessitate an emergency on mine." When it comes to construction and environmental contamination issues, the lack of proper planning will create an emergency for everyone involved. By "emergency" I mean budget-busting unanticipated costs, schedule-destroying delays, compounding change orders, missed milestones, stressed relationships, and agonizing uncertainty. All of this before the first cubic yard of concrete is poured.

The amount of planning for construction projects is phenomenal. All the resources expended to estimate every aspect of the process, every cubic foot of concrete, pound of steel, inch of wire, square foot of drywall, etc. Then there's the 3D modeling, building information modeling, mobile apps, 3D scanning, etc. However, when it comes to environmental (contamination), doing the bare minimum and flying blind seems to be the "go to" approach for many developers. Putting the risk onto their construction manager (CM-at-risk) or general contractor will unnecessarily increase costs due to the risk of uncertainty; however, most CMs/GCs will push back and insist the owner take on the risk. Is either way really the best choice?

This happens because the need to start planning for environmental issues during construction needs to start before the construction starts which means starting before the construction loan disbursements. Therefore, developer must pay with their own "soft money." This leads to hiring consultants that promise the most for the least but deliver the worst in terms of assessment and plans. The old rule for evaluating construction bids of throwing out the lowest and the highest bids is not a bad rule for evaluating environmental bids; however, that assumes the scope of work is equal across the proposals and they rarely are equal. If a consultant says they can assess an entire city block with only a handful of soil borings, it's time for the buyer to beware.

A good assessment for an urban infill site is made up of three parts:

  • A thorough understanding of the history of a site;

  • Effective sampling methods and frequency that correspond to the types of contamination suspected to be present

  • A full understanding of the future land use and grading plans to understand and minimize the extent of remediation required.

Failures in one or more of these components is common, but can be avoided by doing more than the bare minimum.

Examples include:

  • Failure to understand that historical residential land uses can result in contamination. During the 1800s to early 1900s it was common to burn trash in the back lots of residential and some commercial properties which led to burn ash, lead, carcinogens, etc. being left behind. The historical use of lead-based paint and aerially deposited lead from the exhaust from burning leaded gasoline can also result in the soil on historically residential properties being a hazardous waste.

  • Using direct-push soil sampling, a method using a small diameter rod to collect soil samples, to assess a property for metals. Direct-push sampling severely limits detailed observations of the soil. Distinguishing fill soil from native soil is often the key to understanding the extent of the contamination.

  • Not correlating the project's grading plans with the data to determine what contaminants will be left in-place versus what will be exported will likely result in poorly conceived remediation plans and lost opportunities

These principles were put to the test when I managed the assessment and remediation of the 19 city blocks of the Petco Park and East Village Remediation project. It began with a thorough assessment of the history of each property back to the late 1800s, and then individualized assessment/remediation plans were designed. The remediation of the first six blocks for the future ballpark was completed in three and a half months, and the remainder was completed ahead of the construction schedule. As a result of this thorough planning, there was never a need to go back for additional sampling to satisfy the regulatory agencies.

Too many times consultants choose to limit the effort they put into their assessments because of restrictive budgets. This results in too little historical research, too few sample points, reports without data plotted, and not enough budget for a true understanding of site conditions. Is this the right way to start that new $120M condominium tower? It's like asking your tailor to use as little thread as possible and then being surprised when the suit falls apart. Just as the construction industry is moving to 3D modeling to avoid conflicts and design flaws, developers need to invest sufficiently in the environmental assessment so the consultant can develop a full 3D understanding of the subsurface that allow for the proper planning and execution of the remediation. With a solid assessment and a well thought out plan, remediation costs can be kept to the bare minimum and schedules can be saved.

Chris Spengler is principal of C. Spengler Strategies, He is a 25-year veteran of the environmental consulting field with a focus on brownfields, redevelopment, and remediation during construction.


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