Learn how road salt impacts freshwater ecosystems, including drinking water supplies. Session from a management-based forum hosted by the Cary Institute of Ecosystem Studies about the impact of road salt on natural areas and drinking water supplies, with a focus on successful salt reduction strategies being used regionally and nationally. Speaker: Stuart Findlay, Cary Institute.

1. 1
Salt in Dutchess County Waters –
Where, when, so what?
Stuart Findlay and Vicky Kelly – Cary Institute of
Ecosystem Studies

2. Take Home
• Get ahead of your trajectory
• Think “slow”
• No bad guys
2

3. Some Chloride Reference Points
• Background - ~ 10 mg/L or less [Catskill
Reservoirs, Adirondack lakes (Dan Kelting)]
• Sublethal – 50-100 mg/L Subtle yet Significant
–Biotic Indices
–Microbial processes
–Associations
• EPA Chronic – 230 mg/L
• Drinking Water Std – 250 mg/L
• EPA Acute – 860 mg/L
• Lethal - 1000 or higher

4. SIMPLER
• REFERENCE <10 mg/L
• ENVIRONMENTAL EFFECTS ~ 100 mg/L
• LETHAL > 1000 mg/L
DUTCHESS COUNTY SURFACE WATERS
80 mg/L (+/- 79 SD)

5. Ten Mile
10-40
Crum Elbow
15-50
Casperkill
100-300
(Cunningham et al 2009)
Dutchess County
Chloride
(mg/L)
Wappinger
10-45
Fishkill
10-100
New York
State
Cary IES
EB Wapp Ck

6. Sources of Chloride
(% of flux in Fishkill Creek)
(>80%)
(~1%)
(5-10%)

7. THE UNEXPECTED
(Think “Slow”)
• Long-term increases in concentration
• High concentrations in summer
• Higher concentrations downstream (in summer)

8. Chloride levels are on the rise in the Hudson Valley
0
10
20
30
40
50
60
70
11/14/1984 7/24/1998 4/1/2012
Chloride(mg/L)
EBWC Chloride
V. Kelly IES

9. High concentrations
in summer
0
20
40
1 2 3 4 5 6 7 8 9 10 11 12
MONTH
CHLORIDE(mg/L)
East Branch
Wappinger
Creek, Millbrook
No decline in summer concentrations
(monthly means)

10. FALLKILL CREEK
Aug 2017
Downstream increases in summer
Headwaters
0
20
40
60
80
100
120
140
160
180
200
0 2 4 6 8 10 12
Chloride(mg/L)
Miles Above Hudson River
Mouth

11. • Groundwater or Soil Sorption?
STREAM
Trends and Spatial Patterns
Indicate Slow Flushing

12. Chloride in
Private
Drinking
Water Wells
% of Wells less than
250 mg/L Cl* 90%
20 mg/L Na 40%

13. An Engaging Problem?
• Everyone understands “salt”-opportunity for
education
• Not viewed as a threatening issue -not
(presently) a health hazard or regulated
material
• Point sources don’t always seem to be the
problem (no finger-pointing, low media
attention)
• Everyone would like to use salt more efficiently

14. Take Home
• Get ahead of your trajectory
• Think “slow”
• No bad guys
14