Variable-Density Groundwater Flow and Contaminant Transport, Operable Unit 1, Naval Base Kitsap, Keyport, Washington

Scientific Investigations Report 2020-5066
Prepared in cooperation with the Department of the Navy, Naval Facilities Engineering Command, Northwest
By: , and 



Chlorinated volatile organic compounds (CVOCs) have migrated to groundwater beneath a former 9-acre landfill at Operable Unit 1 (OU-1) on Naval Base Kitsap, which was active from the 1930s through 1973 on the Keyport Peninsula, in Kitsap County, Washington. Biodegradation of CVOCs at OU-1 limits the mass of dissolved-phase CVOCs in groundwater that discharges to surface water, but contaminant concentrations up to 630 milligrams per liter persist in localized areas, likely from the dissolution of residual, non-aqueous phase liquids. Variable-density groundwater-flow and contaminant-transport models were developed using the SEAWAT-Version 4 computer program to simulate the direction and rate of groundwater flow in a 5.9 square-mile (mi2) - area surrounding the Keyport Peninsula, to estimate the CVOC mass in groundwater and the rate of mass loading, and to assess possible remedial activities at OU-1.

The study area is underlain by Quaternary deposits consisting of alternating glacial and interglacial sediments ranging from 500 to 1,500 feet (ft) thick. A hydrogeologic model delineated a sequence of 10 units including a relatively thin package (less than 100 ft) of recent sediments (Vashon Stade and younger) beneath the Keyport Peninsula that are underlain by the much thicker (more than 300 ft) Clover Park Aquitard, which overlies a confined, sea-level aquifer.

Suggested Citation

Yager, R.M., Welch, W.B., Headman, A., and Dinicola, R.S., 2020, Variable-density groundwater flow and contaminant transport, Operable Unit 1, Naval Base Kitsap, Keyport, Washington: U.S. Geological Survey Scientific Investigations Report 2020–5066, 58 p.,

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Description of Study Area
  • Simulation of Constant-Density Groundwater Flow
  • Simulation of Variable-Density Flow and Transport of Chlorinated Ethenes
  • Discussion of Simulation Results
  • Summary
  • Soil-Water Balance (SWB) Model Spatially Distributed Datasets
  • References Cited
  • Appendix 1. Soil-Water Balance (SWB) Model
Publication type Report
Publication Subtype USGS Numbered Series
Title Variable-density groundwater flow and contaminant transport, Operable Unit 1, Naval Base Kitsap, Keyport, Washington
Series title Scientific Investigations Report
Series number 2020-5066
DOI 10.3133/sir20205066
Year Published 2020
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Washington Water Science Center
Description x, 62 p.
Country United States
State Washington
City Keyport
Other Geospatial Naval Base Kitsap
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details