Agenda Item 5-G Semi Annual Groundwater Monitoring Report January - - PowerPoint PPT Presentation

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Agenda Item 5-G Semi Annual Groundwater Monitoring Report January - - PowerPoint PPT Presentation

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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)

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Agenda Item 5-G

Semi Annual Groundwater Monitoring Report

January 14, 2020

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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

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5 10 15 20 25 30 35 40 45 50

ANNUAL RAINFALL (INCHES)

ANNUAL AVERAGE 19.7 inches

Rainfall Patterns

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1998 HISTORIC WET PERIOD 1991 HISTORIC DRY PERIOD

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Montecito Basin - Storage Units

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Montecito Basin – District Wells

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Storage Unit 1

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  • 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

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Storage Unit 1 – All Wells

7 100 200 300 400 500 600 700 800

M-91 D-91 J-92 F-93 S-93 A-94 N-94 J-95 J-96 A-96 M-97 O-97 M-98 D-98 J-99 F-00 S-00 A-01 N-01 J-02 J-03 A-03 M-04 O-04 M-05 D-05 J-06 F-07 S-07 A-08 N-08 J-09 J-10 A-10 M-11 O-11 M-12 D-12 J-13 F-14 S-14 A-15 N-15 J-16 J-17 A-17 M-18 O-18 M-19

ELEVATION ABOVE SEA LEVEL (FT)

1-32 1-33 1-35 1-36 1-37 1-38 1-40 1-42 1-43 1-45 1-47 1-48 1-49 1-50 1-8 1-10 1-18 1-19 1-21 1-28 1-29 1-30 1-18a

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Storage Unit 1 – MWD Wells Only

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50 100 150 200 250 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

ELEVATION ABOVE SEA LEVEL (FT)

Valley Club Live Oaks Hodges Mosby/Office 2 EVR 3 EVR 4 Seaview Las Fuentes EVR 6 EVR 8

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Storage Unit 1 – Hodges Well (MWD)

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50 100 150 200 250 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

ELEVATION ABOVE SEA LEVEL (FT)

Hodges

PEAK AT 196’ 1991 LOW AT 117’ NEW LOW AT 104’ NOW AT 122’ (APPROX. 20% “FULL”)

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Storage Unit 2

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  • 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

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Storage Unit 2

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260 265 270 275 280 285 290 295 300 305 310

ELEVATION ABOVE SEA LEVEL (FT)

2-2 2-3

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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

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Storage Unit 3 – All Wells

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  • 100
  • 80
  • 60
  • 40
  • 20

20 40 60 80 100 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 2018 2019 ELEVATION ABOVE SEA LEVEL (FT) LE II 3-5 3-7 Neal 3-9 Paden 2 3-15 3-16 3-19 Amapola Morgan Underwood Ennisbrook 2 Ennisbrook 5

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Storage Unit 3 – MWD Wells

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  • 150
  • 100
  • 50

50 100 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

ELEVATION ABOVE SEA LEVEL (FT)

LE II Neal Paden 2 Amapola Morgan Underwood Ennisbrook 2 Ennisbrook 5

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Storage Unit 3 – MWD Wells

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  • 20
  • 10

10 20 30 40 50 60 70

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

ELEVATION ABOVE SEA LEVEL (FT)

Neal

PEAK AT 40’ 1991 LOW AT -11’ NOW AT -6’ (APPROX. 10% “FULL”)

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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

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Storage Unit 4 – Private Well

150 200 250 300 350 400 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 ELEVATION ABOVE SEA LEVEL (FT) 4-4

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Storage Unit 4 – Edgewood Well

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  • 15
  • 10
  • 5

5 10 15 20

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

ELEVATION ABOVE SEA LEVEL (FT)

PEAK AT 14’ LOW AT -3’ NOW AT 0’ (APPROX. 40% “FULL”) NEW LOW AT -11

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Summary

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  • 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

  • ngoing 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

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Questions?