Location and Environment

HIGHWAY PROJECT REVIEWS

 

From our perspective, a "regulated materials" site is a property where the soil and/or groundwater is known to be, or has the potential to be, impacted by the intentional or unintentional release of materials or substances which are regulated by the United States Environmental Protection Agency and/or the Iowa Department of Natural Resources. This includes petroleum products, solvents, heavy metals, coal tar constituents, polychlorinated biphenyls , pesticides, etc. Sources of contamination can include leaking tanks or drums, accidental chemical spills, improper waste storage and disposal, general poor housekeeping practices, etc.

Staff from the regulated materials section reviews sites with known or potential contamination issues. Sites may be identified through private database-search companies and/or the review of various state and federal databases including those of the Iowa DNR and EPA, current and historic aerial photographs, Sanborn fire insurance maps, city directories, title searches, county assessor websites, windshield surveys, geographic imagery, and agency and selected property owner interviews.

Regulated materials sites are not typically a key factor in selecting a highway project’s alignment alternative, although some exceptions do exist, e.g., the discovery of former manufactured gas plants/coal tar sites or EPA “Superfund” sites can play a major role in the decision-making process.

The early identification and documentation of regulated materials sites can help the Iowa DOT more fully understand the potential environmental liabilities and constraints associated with contaminated sites and make more informed decisions regarding alignment alternatives. When these sites can be identified and considered early in the process, alternatives that reduce the need to clean up contaminated sites can be incorporated into the planning and design phases. This avoids unnecessary costs, reduces regulatory liability, and prevents potential construction delays.

Once potentially contaminated properties are identified, the Iowa DOT may perform a site sampling investigation for those properties that cannot be avoided or have already been acquired. Staff from the regulated materials section oversees consultants that perform these investigations through the use of statewide service contracts.

The purpose of a site sampling investigation is to verify the presence or absence of contamination in soil, groundwater and other media as appropriate at a specific individual site and an attempt to characterize the nature and projected extent of the contamination at the site or within the area designated for the Iowa DOT’s acquisition. If the investigation findings are significant enough, the Iowa DOT may reconsider the property acquisition and assess other alignment alternatives or investigate the possibility of a partial property acquisition versus a total acquisition.