Tier 2 Assessment

The purpose of Tier 2 assessment is to collect additional site-specific data and, with the use of Tier 2 fate and transport modeling, determine what actual and potential receptors could be impacted by chemicals of concern.

A Tier 2 Site assessment must be conducted and a Site Cleanup Report submitted for all sites when any of the following conditions occur:

• Free phase petroleum product is present at the site.
• The site owner or tank owner/operator has decided to bypass the Tier 1 assessment and go directly to the Tier 2 assessment phase.
• A pathway has failed the Tier 1 assessment.
• During drilling, bedrock was encountered before groundwater.
• Explosive vapor levels were measured during a Tier 1 assessment or recent investigation of the site.

Tier 2 Guidance along with software will help you to fill out the assessment report.

Software for Tier 2 can be downloaded or by contacting Bonnie Garrison at (515)281-6010 or bonnie.garrison@dnr.state.ia.us.

The following documents are in Adobe Acrobat format and require the Adobe Acrobat Reader to be viewed.  To download Acrobat Reader, click on the icon at the bottom of the screen.

• Tier 2 Site Cleanup Report Form (.pdf 168kb)
• Tier 2 Guidance (.pdf 265kb)
       Institutional Control Section (Revised 8/2005) (.doc 75kb)
• Appendix A--Tier 1 Table, Assumptions, Equations and Parameter Values(.pdf 38kb)
• Appendix B--Tier 2 Equations and Parameter Values(.pdf 29kb)
• Appendix C--Lust staff by region (.pdf 366kb)
• Appendix D--Bedrock less than 50 feet deep (.pdf 233kb)
• Appendix E--Environmental Covenant Documents and Institutional Control Guidance
• Appendix F--Using data prior to August 8, 1996(.pdf 26kb)
• Appendix G--Selected passages from Chapter 61 Water Quality Standards(.pdf 11kb)
• Appendix H--Glossary (.pdf 18kb)
• Appendix I--Abbreviations (.pdf 5kb)