Site Investigation

The site investigation phase focuses on confirming contamination, locating any such contamination, and characterizing its nature and extent. It is essential that an appropriately detailed study of the site be performed to identify the cause, nature, and extent of contamination, as well as the possible threats to the environment or people living or working nearby. The results of the site investigation are used in determining goals for cleanup, quantifying risks, determining acceptable and unacceptable risks, and developing effective cleanup plans that minimize delays or costs in the redevelopment and reuse of the property. To ensure that sufficient information is obtained to support future decisions, the potentially applicable cleanup measures and the proposed redevelopment of the site should be considered when identifying data needs.

A site investigation is logically based on the results of the site assessment. The site investigation phase usually includes the analysis of soil and soil gas samples, groundwater, groundwater vapor, surface water, and residual substances on the brownfield site (for example, in old tanks, barrels, and on trash heaps). The potential migration pathways of contaminants are also examined during this phase, and a baseline risk assessment is conducted to determine the risk to human health and the environment. The results of the site audit will strongly influence the immediate follow-up action for site development. Obviously, the larger and more complex the contaminants found on the site, the more time and money will be required to bring the site into a condition fit for redevelopment. Further, there may also be more residual restrictions on site use as a result.

One of the challenges in brownfield management may be the lack of local expertise in site assessment and investigation. Different technologies are available, but access to them is often limited to more developed regions and countries. It is therefore important to hire experienced environmental consultants for all of the technical preparatory work. In this context, a job initially done well can save a lot of money later on. The high quality of information collected helps with better understanding the liabilities and estimating the true value of the land. See box for some examples of river cleanup efforts in the case studies.

Environmental river cleanup in three cities: Ahmedabad, Singapore, and Washington, DC

In the planning phase, remediation and redevelopment plans are defined with precision. An environmental impact assessment and a mitigation plan are also developed as a way of describing, quantifying, and analyzing the environmental impact of the proposed redevelopment. In addition, PPP roles are negotiated, as are the sharing of risks and benefits among participating parties (based on a thorough development appraisal by the developer, and a clear impact analysis performed by the local authority). Finally, incentive schemes and sources of cofunding are identified.

Following close consultations with involved stakeholders, the preferred remediation and redevelopment options are chosen and further elaborated to define the project content, budget and timeframe. This serves several purposes: (a) obtaining the construction permit, (b) securing the funds required for investments from private and public sources, (c) providing detailed solutions to technical problems (for instance, the required cleanup technology), and (d) creating the basis for tender design and documents for procurement. In this phase, the contamination pattern will be characterized with high precision, the site development elaborated in detail (including all main quantities and dimensions, areas and volumes, layouts and appearances of structures and infrastructure), and a site remediation plan will be readied for implementation.