Groundwater Management Program Update Groundwater Level Monitoring - PowerPoint PPT Presentation

Groundwater Management Program Update • Groundwater Level Monitoring • Groundwater Quality Issues Update

30 25 MW - AB4 20 15 10 5 0 -5 -10 -15 -20 1/1/2012 12/31/2012 12/31/2013 12/31/2014 12/31/2015 12/30/2016 12/30/2017 12/30/2018 12/30/2019

10 MW Lone Oak 5 0 -5 -10 -15 -20 -25 -30 -35 -40 1/1/2012 12/31/2012 12/31/2013 12/31/2014 12/31/2015 12/30/2016 12/30/2017 12/30/2018 12/30/2019

10 MW - N28 5 0 -5 -10 -15 -20 -25 -30 -35 -40 1/1/2012 12/31/2012 12/31/2013 12/31/2014 12/31/2015 12/30/2016 12/30/2017 12/30/2018 12/30/2019

30 MW - 6 25 20 15 10 5 0 -5 -10 -15 -20 1/1/2012 12/31/2012 12/31/2013 12/31/2014 12/31/2015 12/30/2016 12/30/2017 12/30/2018 12/30/2019

10 MW - Chuckwagon 5 0 -5 -10 -15 -20 -25 -30 -35 -40 1/1/2012 12/31/2012 12/31/2013 12/31/2014 12/31/2015 12/30/2016 12/30/2017 12/30/2018 12/30/2019

30 MW - 4 25 20 15 10 5 0 -5 -10 -15 -20 -25 -30 1/1/2012 12/31/2012 12/31/2013 12/31/2014 12/31/2015 12/30/2016 12/30/2017 12/30/2018 12/30/2019

MW-4 Monitoring Well Stage Gage

Elevation of Water 35 30 25 20 Feet 15 10 5 0 2/1/2019 3/1/2019 4/1/2019 5/1/2019 6/1/2019 7/1/2019 8/1/2019 H St River Stage MW4

70 65 60 Temperature (F) 55 50 45 40 2/1/2019 2/16/2019 3/3/2019 3/18/2019 4/2/2019 4/17/2019 5/2/2019 5/17/2019 6/1/2019 6/16/2019 7/1/2019 7/16/2019 7/31/2019 AWB MW4

Water Quality Issues Update Regional Contamination Issues Committee • Formed in 2004 in response to • Additional discovery of Aerojet contamination north of the American River • Claims by McClellan that recovery of groundwater levels due to conjunctive use were interfering with remediation timetable (adding 100s of years) • Includes representatives of impacted water suppliers, regulators overseeing sites, and responsible parties • Has met on a quarterly basis (mostly) • Intent has been to • find areas of common interest to improve efficiency for all participants • identify emerging regional water quality concerns early on

Hexavalent Chromium • At recent State Water Board Division of Drinking Water Advisory Group meeting, staff reported: • An economic feasibility white paper and public workshops expected in October or November • Informal rulemaking on maximum contaminant level in late 2019 or early 2020 • Formal rulemaking in late 2020 or early 2021

Aerojet-Related Contaminant Plumes

1,2,3-TCP Maximum Contaminant Levels Exceedances Based on 2018 Sampling

PFAS • Per- and polyfluoroalkyl substances (PFAS) • Human-made fluorinated compounds in use since 1940s • Manufactured in US until early 2000s • Several thousand PFAS compounds exist • Used to make materials resistant to stains, water-proof, and non-stick • Also used in fire suppression (fire-fighting foams) • Extremely persistent and resistant to typical environmental breakdown, so found in air, soil, and water • Also accumulates in human body, so being found in wastewater treatment plants

PFAS continued • Testing ordered in water systems between 2013 and 2015 as part of Unregulated Contaminant Monitoring Rule (UCMR) 3 • PFAS of current concern include Perfluorooctanoic acid (PFOA), Perfluorooctanesulfonic acid (PFOS) • No current drinking water standard, but US EPA established a lifetime Health Advisory Level (HAL) for PFOA and PFOS of 70 nanograms/liter (or parts per trillion) • State Water Board (SWB) adopted the US EPA HAL as the California Response Level (RL). When the RL is exceeded, and concentrations cannot be reduced below the RL, DDW recommends removing the source from service

PFAS continued • The SWB established Notification Levels (NL) of 14 ng/L for PFOA and 13 ng/L for PFOS in 2018. When the NLs are exceeded, the Division of Drinking Water (DDW) recommends that the source be removed from service and treated • SWB has ordered additional sampling in 2019 for drinking water wells within 2 miles of an airport, 1 mile of a municipal landfill, or 1 mile of a well with a UCMR3 detection • 32 wells in Sac County ordered to test • Results expected within next few months • DDW recommending lowering RL for PFOA to 10 ng/L and NL to 5.1 ng/L • DDW recommending lowering RL for PFOS to 40 ng/L and NL to 6.5 ng/L