Section 2: Environmental Site Assessment and Investigations
When hazardous material contamination is discovered, it is likely to delay project development or stop construction until a lengthy, complex and costly investigation and analysis can be completed to determine proper procedures for handling the site. Keys to success in dealing with potentially contaminated sites are:
- early identification and assessment
- early coordination with:
- Design Division (DES)
- Environmental Affairs Division (ENV)
- Right of Way (ROW)
- Construction Division (CST)
- General Services Division (GSD)
- Contract Services Section (CSS)
- Federal Highway Administration (FHWA)
- responsible parties, local entities and regulatory agencies
- early determination and use of measures to avoid or minimize involvement during construction activities at the site.
Environmental site assessments should be performed to identify potentially contaminated sites. The findings of an initial site assessment or investigations performed by the district may indicate the need for more detailed assessment. Environmental consultants may be called in, depending upon the training and experience level of the district's staff. Some of the services a consultant may provide include:
- comprehensive site investigations to fully characterize the type, concentration and location of the hazardous materials likely to be encountered during construction
- development of a preventive action plan
- development of plans and specifications
- monitoring/testing during design and construction.
The district staff's level of direct experience with the type of contamination encountered will also help determine the responsibilities of TxDOT and any environmental consultants. The district should determine which services should be provided by a consultant and which ones can be performed by in-house staff.
It is necessary to coordinate with TxDOT divisions, FHWA, TCEQ and other agencies to ensure timely and efficient project development. The results of the environmental site assessment and investigations are the basis for design and construction considerations. Right-of-way acquisition and utility adjustments should also be analyzed as part of the project development phase.
The environmental site assessment and investigations should provide adequate information so that all design considerations and factors can be examined and analyzed with regard to possible contamination within the proposed project limits. This information should focus on identifying, quantifying and delineating the vertical and horizontal extents of soil and groundwater contamination that will be affected during construction.