Long Island relies solely on groundwater stored in three aquifers for its drinking water supply. Groundwater is recharged through rainfall but over-pumping has caused quantity issues like saltwater intrusion in some areas. Human activities and pollution also threaten water quality. A Long Island Aquifer Management Compact is proposed to oversee groundwater use, develop management plans, study the aquifer systems, and protect this critical resource from overuse and contamination. The Compact would monitor conditions, educate the public, and represent Long Island's water interests.

1. Understanding and Protecting
Long Island’s Drinking Water - -
The Water Below
Sarah Meyland
Director, Center for Water Resources Management, NYIT
1

2. Water for Long Island
• Long Island is the largest island in the
continental U.S.
• 120 miles long and 20 miles wide
• L.I. is underlain by 3 main water-bearing
geologic formations called AQUIFERS.
• The AQUIFERS store all the drinking
water for L.I.
• While still in the aquifers, the water is called
GROUNDWATER. 2

3. Where is the Groundwater Stored?
In the Sand
3

4. 4
The Long Island Aquifer System
Lloyd Aquifer: +70
million years old
Magothy Aquifer:
65 million years old
Glacial Aquifer:
10,000 years old
Groundwater Divide

5. Glacial Aquifer stores 62% of all recharge.
Magothy Aquifer receives 38% of recharge.
Lloyd Aquifer receives 3% of recharge.
5

6. Glaciers (10,000-15,000 years ago) shaped
Long Island’s topography; rain and melting ice
filled the aquifers with fresh water
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Groundwater Divide

7. From the 44-inches of annual rainfall,
about half seeps into (recharges) the
aquifers to become groundwater each
year.
7

8. An Aquifer is like a Bank:
Water In and Water Out

9. ∗ Humans over-pump groundwater in some areas =
QUANTITY Problems (saltwater intrusion)
∗ Nassau County (north & south shore areas)
∗ Suffolk County: North & South Forks
∗ Water tables drops and streams dry up
∗ Humans pollute the groundwater by activities on the land =
QUALITY Problems
∗ Volatile Organic Chemicals (VOCs) = Toxic Chemicals
∗ Nitrates (sewage and fertilizer)
∗ Spills (gasoline, industrial chemicals)
∗ Manufacturing/commercial (> 250 Superfund sites)
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Human Impacts on Groundwater

10. 10
Groundwater Contamination Plumes
Septic Tank Discharge Chemical Spill

11. • Long Island uses about 130 –
150 billion gallons per year.
• Summer water use increases
200 – 400% above winter
water use.
• Lawn watering returns NO
water back to the aquifer.
• The best water is disappearing.
11
How do we use our water?
Water Use through the Year

12. Excessive Summer Water Use Stresses the
Groundwater Supply: Little Recharge
Source:
LI 208 Study

13. ∗ National Average: Per Person Water Use = 100 g/p/day
∗ Nassau County: Per Person Water Use = 140 g/p/day
∗ Suffolk County: Per Person Water Use = 137 g/p/day
∗ Industrial Water Use on L.I. = Unknown
∗ Agricultural Water Use on L.I. = Unknown
13
Per Person Water Use on L.I. is
Above the National Average

14. 14
Saltwater Intrusion in Nassau County

15. ∗ Who is responsible for LI Water?
∗ How is water managed around NY State?
∗ Water Compacts – Used Throughout New York
∗ Long Island needs it own aquifer manager - -
∗ Long Island Aquifer Management Compact
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How Can Long Island Protect and
Manage Its Groundwater Supply?

16. 1. Define how much water is available and how much can
be reliably withdrawn, to help stop saltwater intrusion.
2. Allocate water among all stakeholders and track water
use.
3. Oversee water withdrawals and administer water well
permit program.
4. Develop short-range and long-range water
management plans and implement them.
5. Conduct scientific studies to increase our
understanding of the aquifer systems in cooperation with
the USGS.
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What would an Aquifer Compact Do?
Be our Groundwater Champion!

17. 6. Develop computer models of the aquifers and
management tools for better oversight.
7. Protect water-dependent systems: streams, wetlands,
pond, lakes, etc. from water withdrawal impacts &
pollution.
8. Speed up contaminated site cleanup.
9. Combat saltwater intrusion.
10. Promote better ways to protect groundwater quality
and improve conservation.
11. Work with all interested parties to make groundwater
protection the number 1 priority.
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Compact Responsibilities

18. 1. Promote public education and educational materials.
2. Report annually to the public about new information and
current conditions.
3. Monitor High Risk conditions: drought, salt water intrusion,
sea level rise, climate change, new pollutants.
4. Represent the water interests of Long Island in regional
situations.
5. Work full-time and develop science-based policies.
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Also, a Compact Would

19. 19
We only have
one source of
drinking water.
We ruin or
waste it at our
own peril.
Not to scale
QUESTIONS?
1-29-2016