South Y PCE PW 4_6 Mar 2019_2 slide per page3/5/2019
1
GROUNDWATER AT THE
SOUTH Y
March 6, 2019 6:00 PM – 7:30 pm
City of South Lake Tahoe | Council Chambers
Lukins Brothers
Water Company, Inc.
INTRODUCTIONS
NAME TITLE AFFILIATION
John Thiel, PE General Manager
Jennifer Lukins Assistant Manager
Kirk Woolridge General Manager
Ivo Bergsohn, PG,
CHG Hydrogeologist
Scott Ferguson, PE Supervising WRC
Engineer
Susan Rybarski Assistant Research
Scientist
Lukins Brothers
Water Company, Inc.
3/5/2019
2
OVERVIEW
WORKSHOP DATE TOPICS
PW 1 2/7/2018 •Groundwater & PCE Overview
•Water Agency Approach to Solution
•South Y Feasibility Study
PW 2 8/8/2018 •Water Agency/LRWQCB Updates
•Pre-Design Investigation – Initial Findings
PW 3 11/7/2018 •Water Agency/LRWQCB Updates
•South Y Feasibility Study - Alternatives
PW 4 Today •Water Agency/LRWQCB Updates
•Groundwater Model Evaluation
SOUTH “Y” PLUME
•COC: Tetrachloroethylene (PCE; MCL = 5 ppb)
•Plume Area: 400+ acres
•Impaired Private and Public Water System wells
•Reduces available water production capacity by 3.25 MGD (~5,000 average CA households)
3/5/2019
3
LUKINS BROTHERS WATER COMPANY
California Public Utilities Commission approval of Resolution W-5159 (Grants LBWC
Authority for funding)
LBWC Well 5 Results: PCE: 58 ppb and 60ppb; TCE: 1.3 ppb and 1.4ppb
Grant awarded for GAC filtration system at Well 5
April 2018
June 2018
2019 Anticipated construction of filtration system
Next Steps Awaiting California Department of Water Resources State Revolving
Fund Grant for Feasibility Study to locate potential new water sources
for Lukins
Initial detection over MCL
Planning grant awarded
Preliminary Engineering Report for water system improvements finalized
July 2017
May 2015
Began engineering for GAC filtration system at Well 5
Summer 2014
TAHOE KEYS WATER COMPANY
Hired engineering consultant to develop facilities plan to address
contamination and provide alternatives to safe, reliable water
2009
Fall 2018 Approval to perform water quality monitoring on Well 2 to determine
vertical extent of PCE. Project under review.
Next Steps Use DRI Groundwater Model to determine potential
alternatives.
Initial detection in Well 2 over MCL, well shut-down
Installed GAC filtration to Well 2. Limits pumping capacity
Initial detection in Well 1below MCL, monitor monthly
2012
2016
2017
3/5/2019
4
LRWQCB UPDATE
GROUNDWATER MODEL
3/5/2019
5
QUESTION AND ANSWERS
EXTRA SLIDES
3/5/2019
6
AGENDA
•Introductions
•Overview
•Water Agency Updates
•LRWQCB Update
•Groundwater Model
•Questions and Answers
•Adjourn
BREAK
10- minutes