This document summarizes a study of a storm water detention basin to determine the effects of de-icing salts on the soil properties. Soil samples were taken on a grid across the basin and analyzed for electrical conductivity, infiltration rate, salinity, soil texture, and chemistry. The results showed that electrical conductivity and clay content were highest in the center and north of the basin, while infiltration rates were faster on the sloping sides. Calcium levels were lowest in the center of the basin where electrical conductivity was highest. The results indicate that de-icing salts are affecting some soil properties in the detention basin.

1. Cesar Bustos, Jazmin Villegas, Ricardo Barron
Laura Sanders Ph.D., Jean Hemzacek M.S., Kenneth Voglesonger Ph.D.
Northeastern Illinois University, Department of Earth Science
Introduction
Location: Northeastern Illinois University,
Chicago, IL
storm water detention basin
• De-icing salt applied in winter is
transferred with snow into the basin
• Soil properties expected to be affected by
salts
• Electrical conductivity and salinity
expected to reflect input of salts
• Soil texture may indicate soil deterioration
from salts
• Soil texture: relative proportions of
sand, silt, clay
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
Sandy Clay Sandy Clay
Loam
Silt Loam Loamy Sand
North Basin
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
Sand Clay Sandy Clay Sandy Clay
Loam
Loamy Sand
Center of Basin
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
Loamy
Sand
Clay Loam Silt Loam Silty Clay
Loam
Sandy
Clay
Loam
Sandy
Loam
Sandy
Clay
South Basin
Results
Conclusions
• Infiltration rate is generally related to soil texture: sand
is more permeable; clay is generally impermeable
• Soil textures can be grouped:
clayey: clay, sandy clay
sandy: sand, loamy sand, sandy loam,
sandy clay loam
• EC higher at center of the basin; likely related to water
outlet drain in that location
• Flatter basin bottom at north, and lower, bowl-shaped
south part may affect water-holding patterns and
soil processes.
• Calcium Chloride was detected within the region of the
Basin.
Acknowledgments
We thank the following: Professors Jean Hemzacek, Laura Sanders, and Kenneth Voglesonger and Peer Mentor Tiffany Probst for guiding us and showing support through the project; the USDA for funding to make this research possible; the NEIU Student Center for Science Engagement, including
Marilyn Saavedra-Leyva and Dr. Joseph Hibdon for providing us with resources and helping us through our research; and Mark Bramstedt, Soil Scientist, Natural Resources Conservation Service, for taking time with us and traveling far to show us different soil techniques and useful information. This
project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2010-38422-21271 from the USDA National Institute of Food and Agriculture.
Future research
• Create detailed topographic map of the basin for correlation
of topography with soil properties.
• Increase sampling to verify results of salinity, EC, infiltration,
and soil texture.
• Compare seasonal variations (e.g., early spring vs. late
summer) of soil parameters
Basin Area Map of EC results
Contour interval is 50 μSiemens; highest
recorded EC = 830 μS, lowest = 120 μS
Methods and Materials
Preparing work area
• Survey perimeter of storm water detention basin using
stadia rod and auto level.
• Create sampling grid: 10′ x 20′ using compass and
surveying tape.
Sample Collection
• 1′′-diameter soil probe,
at 20-ft intervals on grid
• Additional sampling based on
environmental differences noted
Analyses
Electrical Conductivity(EC)
• Mix soil sample with deionized water, at 1:1 ratio
• Measure with field Electrical Conductivity (EC) probe
Infiltration Rate
• Insert 7” diameter ring, three inches into the ground
• Cover ring with plastic wrap
• Pour 518 mL of water on top
• Remove plastic wrap; record time for water infiltration
• Repeat procedure
Soil Textural Class
• USDA Field Method
Salinity and Other Chemical Parameters
• Samples selected for analysis based on collected data
• Samples expected to exhibit differences in salinity
• Sent to commercial lab for chemical analyses
Summary
• EC highest at/near lowest (flat) part of basin
• EC lower on sloping sides of basin
• Infiltration rates highly variable; generally highest to north
• Calcium: lowest in basin center
• Sodium: no notable differences throughout basin
• More clay-rich soil found in north and center of basin
Objective
Determine effects of de-icing salts on physical and
chemical properties of soil within a detention basin:
• Salinity
• Electrical Conductivity
• Soil physical properties
Abstract
This project evaluates the impact of de-icing salts on an urban storm
water detention basin. The results of this study can be used to determine
potential use of the basin for planting, and to inform the community
regarding environmental impacts of human activities. The hypothesis is
that the lowest parts of the basin will exhibit higher salinity than the
sloped basin sides. To characterize patterns in soil properties that could
be related to the use of de-icing salts, topsoil samples were extracted at
regular intervals on a grid. Soil samples were analyzed for Electrical
Conductivity (EC), infiltration rate, salinity and related chemistry, and soil
textural class. USDA standard field methods were employed to measure
EC, infiltration rate, and soil texture; chemical analysis was conducted by
a commercial laboratory. Results indicate faster infiltration rates on
sloping sides of the basin than in the flat, low center of the basin. The
bottom of the basin yielded higher EC values than on the sloping sides of
the basin. Soil texture varied across the basin, with distinctions evident
between more sandy soils and more clay-rich soils. Higher EC values
did not, as expected, correlate to higher soil salinity. However, some
high calcium values were found to correlate with lower EC soils.
Soil Textural Class
bars show % of samples in that class Sampling Grid
Lines & Sample Points
1
2
4
3
5
6
7
8
9
Soil Textural
Classes
N
Distance,feet
Distance, feet
0
50
100
150
200
250
300
350
400
Line 1-1 Line 1-2 Line 1-3 Line 2-1 Line 2-2 Line 3-1 Line 3-2 Line 3-3 Line 4-1 Line 4-2
0 Feet 80 Feet 120 Feet 0 Feet 160 Feet 0 Feet 40 Feet 68 Feet 0 Feet 75 Feet
Line- Feet
Soil Infiltration rate
InfiltrationRate,
inches/hour Infiltration Rates
are highly variable
across the basin
1500
2000
2500
3000
3500
4000
0 200 400 600 800 1000
Calcium,ppm
Electrical Conductivity