Study Results

A large-scale, multi-year, scientific study

The study began with an extensive planning effort in 2012 to gather community input and design a study to address key community questions. The engineering firm, HDR Engineering Inc., was hired to assist with the study.

To ensure a credible and scientifically valid study, multiple layers of expertise and review are built into the process, including:

Steering Committee – served by LOTT’s Technical Sub-Committee, made up of the Public Works Directors from the Cities of Lacey, Olympia, and Tumwater; Thurston County’s Director of Environmental Health; and LOTT’s Executive Director, Engineering Director, and Operations and Facilities Director.

Science Task Force – made up of technical experts from the cities of Lacey, Olympia, and Tumwater, Thurston County, the Squaxin Tribe, and the state Departments of Ecology and Health.

Peer Review Panel – contracted with National Water Research Institute for independent peer review by a team of six nationally renowned researchers and technical experts.

Study Tasks
The study is an ambitious multi-year effort made up of four main tasks. Each task is described below, with results from each task posted as they become available.

Task 1: Water Quality Characterization – completed in 2017.
Test groundwater, surface water, wastewater, and reclaimed water in the Hawks Prairie and Tumwater study areas for residual chemicals.

Water Quality Characterization Fact Sheet (PDF) – A general overview of Task 1 activities and findings.

Residual Chemicals in Reclaimed Water, Groundwater, and Surface Water (PDF) – A high level summary and comparison of results from the three Task 1 technical memos.

Task 2: Treatment Effectiveness Evaluation – underway; completion expected in late 2018.
Analyze where reclaimed water infiltrated at the Hawks Prairie site goes, how quickly the water travels, and how the water quality changes over time.

Task 3: Risk Assessment – underway; completion expected in late 2018.
Evaluate relative risks to people and the environment that may result from infiltrating reclaimed water to replenish groundwater.

Task 4: Cost/ Benefit Analysis not yet begun; completion expected in early 2019.
Consider long-term costs and benefits of various options for managing reclaimed water, including various levels of treatment and alternative uses of the water.