Increased River Salinization and Alkalinization
of Fresh Water in the Eastern U.S.
Courtesy Michael Pennino
River Temperatures in Maryland-Washington D.C.
20
R2 = 0.43
Average Annual Temperature ºC
18
R2 = 0.38
16
R2 = 0.22
14
12
10
8
Potomac River, Washington D.C.
6
Patuxent River, Solomons, Maryland
4
Gunpowder River, Baltimore, Maryland
2
0
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
Year
Other warming rivers in New York, Montana, Oregon…
Kaushal et al. (2010), Front. in Ecol. And Env. Science
Outline
I.
How are human activities increasing
alkalinization of fresh water?
II.
How are human activities increasing
salinization of fresh water?
Outline
I.
How are human activities increasing
alkalinization of fresh water?
II.
How are human activities increasing
salinization of fresh water?
I. Background
• Streams and rivers are transporters of carbon
• Bicarbonate alkalinity is buffering capacity
• Alkalinity can be influenced by land use
• Chemical weathering can generate alkalinity
Objectives
• Investigate trends and identify predictors of
river alkalinization in the eastern U.S.
• Investigate impacts of land use and hydrologic
variability on river alkalinization
97 Sites
Spanning:
Watershed Size
Elevation
Lithology
Land Use
Kaushal et al. (2013), ES&T
Kaushal et al. (2013), ES&T
Saddle River at Lodi New Jersey
Calcium Concentration (mg/L)
80
70
60
50
40
30
20
10
0
Nov-23
R² = 0.1949
Jul-71
Nov-77
Aug-82
Aug-87
Feb-93
Feb-99
Aug-06
Maurice River at Norma New Jersey
Calcium Concentration (mg/L)
6
5
4
3
2
1
R² = 0.4316
0
Mar-53
Apr-75
May-79
Nov-82
Mar-88
Mar-93
Aug-99
Kaushal et al. (2013), ES&T
Aug-06
40% of Variation in
River Alkalinization
Rates Predicted by:
Lithology
Acid Deposition
Elevation
Kaushal et al. (2013), ES&T
Land Use and Stream Alkalinization
• Land development
Tile drains in
Hancock County,
Indiana
– Liming, Fertilizer, Tile Drains
– Concrete, Sewage, Storm
Drains
• Land use impacts on stream
alkalinization?
Storm drains in
Baltimore,
Maryland
Kaushal and Belt (2012), Kaushal et al. (In Press)
Baltimore Ecosystems Study LTER
Forested Watersheds
Agricultural Watersheds
Suburban Watersheds
Urban Watersheds
Kaushal et al. (Unpub Data)
Kaushal et al. (Unpub Data)
Outline
I.
How are human activities increasing
alkalinization of fresh water?
II.
How are human activities increasing
salinization of fresh water?
II. Increased salinization of fresh water
Courtesy Ken Belt
Overview
• Impervious surfaces in U.S. approaches
the state of Ohio (112,610 km2)
• 10,000 miles of new roads and 1 million
single-family homes in this decade
• Salt is commonly used above 39° N
latitude
Salt
• Concentrations of sodium and chloride have
been increasing for decades in the Northeast
• Chronic concentrations of chloride > 250
mg/L may be toxic to some sensitive
freshwater life
• Road salt is currently not regulated in the
United States
Objective
• Investigate relationship between land
use change and increased salinity of
streams in northeastern U.S
Drinking Water Supply to Baltimore, Maryland
Chloride Concentration (mg/L)
A.
60
50
LMR0015
MDE0026
BEA
R2 = 0.74
40
30
R2 = 0.44
20
R2 = 0.65
10
0
M- A- M- F- J- D- N- O- S- A- J- J- M- A- M79 81 83 85 87 88 90 92 94 96 98 00 02 04 06
Date
Kaushal et al. (2005) PNAS
White Mountains, New Hampshire
Chloride Concentration (mg/L)
C.
140
Stream Near Highway
120
Forested Reference Stream
100
80
60
R2 = 0.70
Construction of
Interstate
Highway
40
20
0
J- A- A- S- O- O- N- N- D- J- J- F- M- M- A- M- M- J67 69 71 73 75 77 79 81 83 86 88 90 92 94 96 98 00 02
Date
Kaushal et al. (2005) PNAS
Study Sites
•Impervious surface has increased by >
40% from 1990 to present
•Typically only 18.2 inches of snow
Mean Annual Chloride Concentration (mg/L)
600
1998
2001
500
1999
2002
2000
400
2
R = 0.81
300
Chronic Toxicity to Freshwater Life
200
Toxicity to Most Land Plants
100
0
0
10
20
30
40
Percent Impervious Surface in Watershed
Kaushal et al. (2005) PNAS
50
Summary
• Long-term shift from freshwaters to saline and alkaline
throughout Eastern U.S.
• Acid rain, land use, geology linked to alkalinization
• Current rate of development and application of road
salt can lead to long-term salinization
• Salinization remains chronically high during summer
Acknowledgements
Collaborators/Co-authors: Gene Likens (CIES and U. Conn), Michael Pace (UVA),
Ken Belt (USFS), Paul Mayer (EPA), Ryan Utz (NEON), Jake Beaulieu (EPA), Philippe
Vidon (SUNY), Peter Groffman (CIES), Norb Jaworski (EPA Retired), Bill Stack
(CWP), Claire Welty (UMBC), Andrew Miller (UMBC), Arthur Gold (URI), Lawrence
Band (UNC), Elizabeth Canuel (VIMS), Amy Shields (EPA), Baltimore Ecosystem
Study LTER Site
Postdoctoral Associates: Dr. Shuiwang Duan, Dr. Bala Mathukumalli
Graduate and Undergraduate Students: Tamara Newcomer, Michael Pennino,
Rose Smith, Gwen Sivirichi, Carolyn Klocker, Katie Delaney, Kristy Hopfensperger,
Jon Urban, Tess Van Orden, Evan Smith, Evan McMullen, Harold ManriqueHernandez, Benjamin Wu, Tom Doody
Technicians: Ashley Sides, Casey Sperling, Ellen Moon, Melissa Grese, Casie
Smith, Metthea Yepsen, Julia Gorman
Research Support: NSF, NASA, Maryland Sea Grant, D.C. Water, EPA