Agenda Item 5-G Semi Annual Groundwater Monitoring Report January 14, 2020 montecitogsa.com
Monitoring Program • Started in 1983 with 15 public and private wells to monitor basin water levels twice per year (before and after rainy season) • Fall 2019 survey - 56 wells sampled • 19 District owned, 37 private • Well Sounding Procedure: • 24-hour down time prior to sounding • Sounding equipment lowered down well to determine water surface elevation related to reference point • Depth to groundwater translated to elevation above mean sea level • District well levels are reported to California Statewide Groundwater Elevation Monitoring (CASGEM) Program as required by SGMA montecitogsa.com
Rainfall Patterns 50 1998 HISTORIC WET PERIOD 45 ANNUAL RAINFALL (INCHES) 40 ANNUAL AVERAGE 35 19.7 inches 1991 HISTORIC 30 DRY PERIOD 25 20 15 10 5 0 montecitogsa.com 3
Montecito Basin - Storage Units montecitogsa.com 4
Montecito Basin – District Wells montecitogsa.com 5
Storage Unit 1 • 8 out of 35 recovered 2 to 28 feet during summer 2019 • 25 out of 35 declined 1 to 32 feet during summer 2019 • Remaining 2 wells were at same level • Recharge: Although groundwater levels were, on average, at the same level throughout summer 2019, they recovered 14 feet in last year • Deficit: On average, groundwater remains of 17 feet below historic dry level elevations and 58 feet below historic wet weather elevations • 20% “full”: Using one inactive well as an example, the groundwater levels in this storage unit are at 20% of their historic high levels montecitogsa.com 6
ELEVATION ABOVE SEA LEVEL (FT) 100 200 300 400 500 600 700 800 0 Storage Unit 1 – All Wells M-91 1-49 1-32 D-91 J-92 F-93 S-93 1-50 1-33 A-94 N-94 J-95 J-96 1-8 1-35 A-96 M-97 O-97 M-98 1-10 1-36 D-98 J-99 F-00 S-00 A-01 1-18 1-37 N-01 J-02 J-03 A-03 1-19 1-38 M-04 O-04 M-05 D-05 1-21 1-40 J-06 F-07 S-07 A-08 1-28 1-42 N-08 J-09 J-10 A-10 M-11 1-29 1-43 O-11 M-12 D-12 J-13 1-30 1-45 F-14 montecitogsa.com S-14 A-15 N-15 1-18a 1-47 J-16 J-17 A-17 M-18 1-48 O-18 7 M-19
ELEVATION ABOVE SEA LEVEL (FT) 100 150 200 250 50 Storage Unit 1 – MWD Wells Only 0 1991 1992 1992 Valley Club 1993 1994 1995 Live Oaks 1996 1997 Hodges 1998 1999 Mosby/Office 2 2001 2002 2003 EVR 3 2004 2005 EVR 4 2007 2008 Seaview 2009 2010 Las Fuentes 2011 2012 2013 EVR 6 2014 montecitogsa.com 2015 EVR 8 2016 2017 2018 8 2019
Storage Unit 1 – Hodges Well (MWD) 250 NOW AT 122’ PEAK AT 196’ (APPROX. 20% “FULL”) ELEVATION ABOVE SEA LEVEL (FT) 200 150 100 1991 LOW AT 117’ NEW LOW AT 104’ 50 0 1991 1992 1992 1993 1994 1995 1996 1997 1998 1999 2001 2002 2003 2004 2005 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 montecitogsa.com Hodges 9
Storage Unit 2 • Low producing basin with clayey soils and small groundwater bearing deposits • Not many known active producing wells • Only two active private wells under District monitoring program • Minimal Recharge: Both wells are at exact same depth as one year prior • Deficit: Wells are near 1991 historic dry levels and an average of 12 feet below historic wet weather levels montecitogsa.com 10
Storage Unit 2 310 305 300 ELEVATION ABOVE SEA LEVEL (FT) 295 290 285 280 275 270 265 260 montecitogsa.com 11 2-2 2-3
Storage Unit 3 • Largest yielding storage unit • 3 out of 17 wells recovered 2 to 4 feet during summer 2019 • 7 out of 17 declined 3 to 8 feet during summer 2019 • Remaining 7 wells were at the same elevation • Recharge: on average, groundwater declined 2 feet during summer 2019 but still recovered 8 feet over the last year • Deficit: groundwater is at an average of 8 feet above historic dry weather levels and 21 feet below historic wet weather elevations • 10% “full”: Using one inactive well as an example, the groundwater levels in this storage unit are at 10% of their historic high levels montecitogsa.com 12
ELEVATION ABOVE SEA LEVEL (FT) -100 100 -80 -60 -40 -20 20 40 60 80 0 Storage Unit 3 – All Wells 1983 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2005 2006 2007 2008 2009 2010 2012 2013 2014 2015 2016 2017 montecitogsa.com 2018 2019 Ennisbrook 5 Ennisbrook 2 Underwood Morgan Amapola 3-19 3-16 3-15 Paden 2 3-9 Neal 3-7 3-5 LE II 13
ELEVATION ABOVE SEA LEVEL (FT) -150 -100 100 -50 50 0 Storage Unit 3 – MWD Wells 1991 1992 1992 1993 1994 1995 1996 1997 1998 1999 2001 2002 2003 2004 2005 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 montecitogsa.com 2017 2018 2019 Ennisbrook 5 Ennisbrook 2 Underwood Morgan Amapola Paden 2 Neal LE II 14
ELEVATION ABOVE SEA LEVEL (FT) -20 -10 10 20 30 40 50 60 70 Storage Unit 3 – MWD Wells 0 1991 1992 1992 1991 LOW AT -11’ 1993 PEAK AT 40’ 1994 1995 1996 1997 1998 1999 2001 2002 2003 2004 Neal 2005 2007 2008 2009 2010 (APPROX. 10% “FULL”) NOW AT -6’ 2011 2012 2013 2014 2015 montecitogsa.com 2016 2017 2018 2019 15
Storage Unit 4 • Only two active wells under monitoring program • 1 District Well (Edgewood), 1 private well • Both wells have shown steady groundwater levels over the last 3 years • Both wells remain at or below historic dry weather levels • 40% “full”: Using Edgewood well as an example, the groundwater levels in this storage unit are at approx. 40% of their historic high levels montecitogsa.com 16
Storage Unit 4 – Private Well 400 ELEVATION ABOVE SEA LEVEL (FT) 350 300 250 200 150 montecitogsa.com 1992 1993 1994 1995 1996 1997 1998 1999 2001 2002 2003 2004 2005 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 4-4
ELEVATION ABOVE SEA LEVEL (FT) -15 -10 10 15 20 -5 0 5 Storage Unit 4 – Edgewood Well 1991 1992 1992 1993 1994 1995 LOW AT -3’ 1996 1997 1998 PEAK AT 14’ 1999 2001 2002 2003 2004 2005 2007 NEW LOW AT -11 2008 2009 2010 2011 2012 2013 (APPROX. 40% “FULL”) NOW AT 0’ 2014 montecitogsa.com 2015 2016 2017 18 2018 2019
Summary • Fall 2019 Groundwater Monitoring Program included 56 private and District wells • On average, groundwater levels declined slightly in all four storage units during summer 2019, likely due to the lack of rainfall and ongoing pumping • On average, groundwater levels recovered 3 to 14 feet in all storage units in the past year (exception: Storage Unit 2 stayed the same) • Groundwater levels in all basins remain at or near historic dry weather levels and 12 to 58 feet below historic wet weather levels • Based on a small set of wells, groundwater levels are at an estimated 10-40% of the basin ‘full’ capacity based on historic high groundwater levels montecitogsa.com 19
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