OUD 33245 U.S. Army, Alaska Prepared for U.S. Army Engineer District- Alaska Final RI/FS Operable Unit D Fort Richardson, Alaska Volume Ta Remedial Investigation Report November 1998 Prepared by I4S:I oU-D 33246 Consulting. Engineering kemediation 4600 Busieess Park Blvd. Suite 22 Anchorage, AK 99503-7143 (907) 561-5700 HTRW Contract No. DACA85-94-D001 O FAX (907) 273-4555 Delivery Order: 0021 ENSR Project No.: 9000-107 November 19, 1998 Mr. Brian West U.S. Army Engineer District, Alaska CEN PA-EN P.O. Box 898 Anchorage, Alaska 99506-0898 Subject: Final Deliverable Remedial Investigation/Feasibility Study, OUD, Fort Richardson, Alaska. Dear Mr. West: This letter is to transmit 17 copies plus one original of the Final Remedial Investigation! Feasibility Study (Ri/FS) rteport for OUD. included in the 17 copies is one unbound, 3-hole punched copy. We have also shipped two of the copies directly to Matt Wilkening (EPA Region 10- Seattle, WA). This deliverable consists of the tina) version of the OUD Remedial Investigation (Volume la) plus Appendices (Volume lb) and the OUD Risk Assessment (Volume lia) documents. The Postwide Risk Assessment (Volume lib) and the draft final DUD Feasibility Study (Volume Ill) will be submitted under separate cover. Please note that comments pertaining to these redline/strikeout documents will be included in the front of their respective binders. We have enjoyed working with you on this project. If you have any questions, please don't hesitate to call me at 561-5700. SteMe Wrenn Chris L. Humphr y, P.E. Delivery Order Manager Program Manager OU-D 33241 U.S. Army, Alaska Prepared for U.S. Army Engineer District- AIska Final RI/F S Operable Unit D Fort Richardson, Alaska Volume Ia Remedial Investigation Report November 1998 Prepared by L4SI OUD REMEDIAL INVESTIGATION REPORT FINAL Oh-D 33248 CONTENTS 1.0 INTRODUCTION ............................................................................................... 1-1 1.1 Federal Facility Agreement .............................................................................. 1-1 1.2 Remedial Investigation Report Purpose and Overview ...................................... 1-1 1.3 Fort Richardson Background ............................................................................. 1-2 1.4 QUO Source Areas ........................................................................................... 1-3 1.5 Document Presentation .................................................................................... 1-3 Figure 1-1 Site Locations .............................................................................. 1-4 2.0 PHYSICAL CHARACTERISTICS OF THE STUDY AREA ................................ 2-1 2.1 Demography .................................................................................................... 2-1 2.2 Ecology ............................................................................................................ 2-1 2.2.1 Flora ..................................................................................................... 2-1 2.2.2 Fauna ................................................................................................... 2-2 2.3 Climatology ....................................................................................................... 2-2 2.3.1 Temperature ......................................................................................... 2-3 2.3.2 Wind ..................................................................................................... 2-3 2.4 Geology ............................................................................................................ 2-3 2.5 Hydrology ......................................................................................................... 2-5 Attachment 2.1 - Tables and Figures 3.0 STUDY AREA INVESTIGATION ....................................................................... 3-1 3.1 Field Investigation Methods ............................................................................. 3-1 3.1.1 Surface Soil Sampling Procedures ....................................................... 3-1 3.1.2 Surface Water and Sediment Sampling Procedures ............................. 3-2 3.1.3 Soil Boring and Logging Procedures .................................................... 3-2 3.1.4 Monitoring Well Installation, Development, and Sampling .................... 3-3 3.1.5 Water Level Survey .............................................................................. 3-4 3.1.6 Surveying ............................................................................................. 3-5 3.2 Analytical Program ........................................................................................... 3-5 3.2.1 Analytical Laboratories ......................................................................... 3-5 3.2.2 Project and QAIQC Samples and Analytical Methods .......................... 3-6 3.2.3 Data VerificationNalidation Procedures ................................................ 3-6 Attachment 3.1 - Tables. 4.0 STUDY AREA DESCRIPTIONS AND NATURE AND EXTENT OF CONTAMINATION ............................................................................................ 4-1 4.1 Building 35-752 Source Area ............................................................................ 4-3 4.1.1 Environmental Setting ........................................................................... 4-3 4.1.2 Past Practices ...................................................................................... 4..4 4.1.3 Underground Storage Tanks ................................................................ 4-4 4.1.4 Previous Investigations ......................................................................... 4-6 9000-107 j November1998 Recyc'ed Paper OUD REMEDIAL INVESTIGATION REPORT FINAL 4.1.5 Remedial Investigation 4-11 4.1.6 UST 110g Investigation 4-1g 4.2 Building 45-590 Source Area 4-21 4.2.1 Environmental Setting ......................................................................... 4-21 4.2.2 Past Practices ..................................................................................... 4-22 4.2.3 Previous Investigations ....................................................................... 4-23 4.2.4 Remedia' Investigation ....................................................................... 4-26 4.3 Building 726 SQUrCe Area ............................................................................... 4-31 4.3.1 Environmental Setting......................................................................... 4-31 4.3.2 Past Practices ..................................................................................... 4-31 4.3.3 Previous Investigations ....................................................................... 4-32 4.3.4 Remedial Investigation ....................................................................... 4-33 4.4 Building 796 Source Area ............................................................................... 4-37 4.4.1 Environmental Setting ......................................................................... 4-37 4.4.2 Past Practices ..................................................................................... 4-37 4.4.3 Previous Investigations ....................................................................... 4-39 4.4.4 Remedial Investigation ....................................................................... 4-41 Attachment 4.1 - Section 4.1 Tables arid Figures. Attachment 4.2 Section 4.2 Tables and Figures. Attachment 4.3 - Section 4.3 Tables and Figures. Attachment 4.4 - Section 4.4 Tables and Figures. 5.0 FATE AND TRANSPORT ................................................................................. 5-1 5.1 Introduction ...................................................................................................... 5-1 5.2 Transformation Processes ............................................................................... 5-2 5.2.1 Biodegradation ..................................................................................... S-2 5.2.2 Abiotic Mechanisms .............................................................................. 5-3 5.3 Transport .......................................................................................................... 5-3 5.3.1 Hydrostratigraphy ................................................................................. 5-3 5.3.2 Groundwater Flow Ch2ractenstics ........................................................ 5-4 5.3.3 Contaminant Transport, Dilution, and Attenuation ................................. 5-4 5.4 Site-Specific Discussions ................................................................................. 5-5 5.4.1 Building 35-752 ..................................................................................... 5-5 5.4.2 Building 726 .......................................................................................... 5-6 5.4.3 Building 45-590 ..................................................................................... 5-7 5.4.4 Building 796 .......................................................................................... 5-7 5.5 Conclusions ...................................................................................................... 5-8 6.0 CONCLUSIONS ................................................................................................ 6-1 Figure 6-1 - Building 45-590 Conceptual Site Model ........................................ 6-4 Figure 6-2