DETERMINING GROUNDWATER SUSTAINABILITY A PUBLIC-TRUST RESOURCE - - PowerPoint PPT Presentation

▶
determining groundwater sustainability a public trust
SMART_READER_LITE
LIVE PREVIEW

DETERMINING GROUNDWATER SUSTAINABILITY A PUBLIC-TRUST RESOURCE - - PowerPoint PPT Presentation

Jan 17, 2023 507 likes •764 views

National Park Service U.S. Department of the Interior Natural Resource Science and Stewardship DETERMINING GROUNDWATER SUSTAINABILITY A PUBLIC-TRUST RESOURCE PERSPECTIVE 2015 Water Resource Sustainability Issues on Tropical Islands

slide-1
SLIDE 1

National Park Service U.S. Department of the Interior Natural Resource Science and Stewardship

DETERMINING GROUNDWATER SUSTAINABILITY – A PUBLIC-TRUST RESOURCE PERSPECTIVE

2015 Water Resource Sustainability Issues on Tropical Islands Honolulu, Hawai‘i December 1, 2015 Paula A. Cutillo, NPS Water Resources Division

E X P E R I E N C E Y O U R A M E R I C A ™

slide-2
SLIDE 2

The Water Budget Myth

  • The source of water derived from wells (Theis 1940)
  • Safe yield (Lohman 1979)
  • The water budget myth (Bredehoeft et al. 1982)
  • Why “safe yield” is not sustainable (Sophocleous 1997)
  • Safe yield and the water budget myth (Bredehoeft 1997)
  • Sustainability of ground-water resources (Alley et al. 1999)
  • The water budget myth revisited (Bredehoeft 2002)

The idea that the recharge is important in determining the magnitude of sustainable development is a myth.

(Bredehoeft 2002)

slide-3
SLIDE 3

Source of Water Derived from Wells

All water discharged by wells is balanced by a loss

  • f water somewhere.

(Theis 1940)

 Where are the losses?  Are they acceptable?

slide-4
SLIDE 4

Impacts of Groundwater Withdrawals

(Curruth 2003)

slide-5
SLIDE 5

Pre-Development

(Barlow & Leake 2012)

slide-6
SLIDE 6

Removal of Water from Storage

  • lowered water levels
  • rising saltwater

(Barlow & Leake 2012)

slide-7
SLIDE 7

Captured Groundwater Discharge

  • streamflow depletion
  • less freshwater discharge
  • saltwater intrusion

(Barlow & Leake 2012)

slide-8
SLIDE 8

Factors That Affect Capture

 Aquifer properties  Distance between wells and boundaries  Pumping rate

Recharge *Location, location, location

slide-9
SLIDE 9

Submarine Groundwater Discharge

Image courtesy Craig Glenn/University of Hawai‘i SOEST

slide-10
SLIDE 10

‘Aimakapā Fishpond

slide-11
SLIDE 11

What Is Groundwater Sustainability?

The State’s first definition of sustainability:

 Respects the culture of

communities

 Balances economic,

community, and environmental priorities

 Meets needs of the present

without compromising the ability of future generations to meet their own needs

slide-12
SLIDE 12

Sustainable Yield

“Sustainable yield” means the maximum rate at which water may be withdrawn from a water source without impairing the utility or quality of the water source as determined by the commission.

STATE WATER CODE Chapter 174C of the Hawai‘i Revised Statutes

slide-13
SLIDE 13

Saltwater Intrusion

Chloride (milligrams per liter) Pumpage (million gallons per day) http://hi.water.usgs.gov/recent/westhawaii/chloride.html

Keauhou Aquifer System Sustainable Yield = 38 million gallons per day Kahalu‘u Shaft Pumpage = 4 million gallons per day

KAHALU‘U SHAFT

slide-14
SLIDE 14

Declining Water Levels

Keauhou Aquifer System Sustainable Yield = 38 million gallons per day Keauhou Aquifer System pumpage = 15 million gallons per day Hualalai Deepwell Pumpage = 0.84 million gallons per day

Instantaneous Water Level at Hualalai Deepwell (Commission on Water Resource Management 2014) Water level (feet above mean sea level)

slide-15
SLIDE 15

1980 Robust Analytical Model (RAM)

Freshwater-lens system

Recharge & wells evenly distributed

Sharp interface Saltwater Freshwater Lens

slide-16
SLIDE 16

1980 Robust Analytical Model (RAM)

Freshwater-lens system

Recharge & wells evenly distributed

Sharp interface

In view of the above limitations, the sustainable yield estimates should be used as a guide in planning rather than an inflexible constraint.

(1990 Water Resources Protection Plan)

Saltwater Freshwater Lens

slide-17
SLIDE 17

Public Trust Resources

 If the RAM-calculated sustainable yield cannot prevent

saltwater intrusion in a coastal well, how well will it protect public trust resources?

slide-18
SLIDE 18

Capture Zone Delineation

(Whittier et al. 2010)

slide-19
SLIDE 19

Capture Zone Delineation (Preliminary)

(Data courtesy Robert Whittier/State of Hawai‘i Department of Health)

slide-20
SLIDE 20

1999 USGS Numerical Model

(Oki et al. 1999)

Capture = 3 million gallons per day in park

(Modified from Oki et al. 1999)

slide-21
SLIDE 21

Summary

 Capture a function of well location (not recharge)  Numerical models can estimate where capture occurs  Sustainability guided by estimates of capture

  • Where will capture occur?
  • How much is acceptable for public trust resources?

(Curruth 2003)

slide-22
SLIDE 22

University of HI Craig Glenn Joe Fackrell Jacque Kelly Lori Tango USGS Delwyn Oki Scot Izuka David Foote Eric Grossman

Acknowledgements

slide-23
SLIDE 23

Water Resources Division

Natural Resource Science and Stewardship http://www.nature.nps.gov/water/index.cfm National Park Service U.S. Department of the Interior