Transcript Mike Stone: Facts about Chlorides Presentation

Winter maintenance, chlorides and parking lots:
Managing more with less!
Dr. M. Stone
Department of Geography and Environmental
Management
University of Waterloo
Partnering for Snow
Management Success
2010 Snow and Ice Symposium
Mississauga, Ontario
Overview
• Road Salt and the Environment
• Winter Maintenance and Parking Lots
• Clarkson Go Station Parking Lot Study
• Smart About Salt Program
• Barriers to Implementation
Impacts of road salt on source water
Mass loading influenced by:
Background deposition
Wind
Splash
Spray
POT 406
RUM 329
Run-off
Groundwater Transport
•
•
•
•
•
•
Season
Road type/class
Snow clearing practices
Drainage infrastructure
Subsurface geology
Lawn watering
Highly spatially and temporally heterogeneous.
Historical Context
Canadian Environmental
Protection Act, 1999
(Environment Canada, 2001) –
significant losses of chloride from
road salt adversely impact
- freshwater ecosystems
- terrestrial ecosystems (soil, vegetation
& wildlife)
- drinking water supplies
http://www.ec.gc.ca/substances/ese/eng/psap/final/roadsalts.cfm
Historical Context
Code of Practice for the Environmental Management of Road
Salt, 2004
Designed to help municipalities/authorities better manage salt
use to reduce adverse environmental impacts of chloride while
maintaining road safety.
http://www.tac-atc.ca/english/resourcecentre/roadsalt.cfm
Historical Context
Recommendations of the Code:
1. Develop salt management plans, based on a review of existing
road maintenance operations, identification of means and goal
setting to reduce the negative impacts of salt releases
2. Implement best management practices (BMPs) in areas of salt
application, salt storage and snow disposal as reported in the
Transportation Association of Canada’s (TAC) Syntheses of Best
Management Practices.
Syntheses of Best Practices - Road Salt
Management
1 Salt Management Plans
2 Training
3 Road and Bridge Design
4 Drainage and Stormwater Management
5 Pavements and Salt Management
6 Vegetation Management
7 Design and Operation of Road Maintenance Yards
8 Snow Storage and Disposal
9 Winter Maintenance Equipment and Technologies
http://www.tac-atc.ca/english/resourcecentre/roadsalt.cfm
Historical Context
Assumption:
Voluntary, state-of-the-art salt management practices when applied
as per Code recommendations will benefit the environment and road
authorities by:
- reduce chloride levels
- improve water & soil conditions
- increase operational efficiency
- improve roadway safety
- provide cost savings
APPLIES TO ORGANIZATIONS THAT APPLY > 500 T SALT/YEAR
Mullaney, J.R., Lorenz, D.L., Arntson,
A.D., 2009, Chloride in groundwater
and surface water in areas underlain
by the glacial aquifer system,
northern United States: U.S.
Geological Survey Scientific
Investigations Report 2009–5086, 41
p.
The link to the full report can be found on the NAWQA glacial aquifer system
web page at:
http://water.usgs.gov/nawqa/studies/praq/glacaq/index.html
Source: Mullaney et al (2009) USGS Scientific
Investigations Report 2009–5086.
Groundwater Cl levels in the NE US
Source: Mullaney et al (2009) USGS Scientific
Investigations Report 2009–5086.
Groundwater Na levels in the NE US
Source: Mullaney et al (2009) USGS Scientific Investigations
Report 2009–5086.
Maximum Cl levels in NE US
Mullaney et al (2009) U.S. Geological Survey Scientific
Investigations Report 2009–5086, 41 p.
Historical Salt Loading
Region of Waterloo
WELLHEAD PROTECTION
SENSITIVITY AREAS
WOOLWICH
WELLESLEY
WATERLOO
CAMBRIDGE
KITCHENER
SENSITIVITY AREAS
WILMOT
Greenbrook Well Field
Sensitivity 1
Sensitivity 2
Sensitivity 3
NORTH
DUMFRIES
Sensitivity 4
WHPA to be Revised
Municipal Wells
0
5km
WELLHEAD PROTECTION
SENSITIVITY AREAS
WOOLWICH
WELLESLEY
WATERLOO
East
West
CAMBRIDGE
KITCHENER
SENSITIVITY AREAS
WILMOT
Greenbrook Well Field
Sensitivity 1
Sensitivity 2
Sensitivity 3
NORTH
DUMFRIES
Sensitivity 4
WHPA to be Revised
Municipal Wells
0
5km
Waterloo Moraine
WEST
EAST
THE WATERLOO MORAINE
PERCHED
AQUIFER
(Possibly "Upper" Maryhill Till, Local" till,
Tavistock Till, or Port Stanley Till)
Nith River
AQUITARD 1
AQUITARD 1
Grand River
MANNHEIM AQUIFER
GREENBROOK
AQUIFER
AQUITARD 2 (Maryhill Till)
AQUITARD 1
GREENBROOK AQUIFER
AQUITARD 3 (Catfish Creek Till)
PARKWAY AQUIFER
AQUITARD 4
Bois
Blanc
Formation
Bass
Islands
Formation
PARKWAY AQUIFER
AQUIFER 4
AQUIFER 4
Salina Formation
Guelph Formation
0
10 km
Paul Martin, WHI
Greenbrook Well Field
K5
K6
K3
10 year
capture
zone
K4B
K1
K8
K2
0
1 km
• 100 years of production history.
• 5 wells pumping ~ 3 million gals/day.
• average well depth, 180 ft. in glacial sediments.
• progressive increase in Na and Cl concentrations
over past 30-40 years.
Chloride Concentration at the
Greenbrook Well Field
Chloride (mg/L)
400
K5
300
K1
drinking water limit
K4b
200
K2
100
K3
0
1960
1970
1980
Year
1990
2000
1950
Kitchener-Waterloo Road Network
Greenbrook Well Field
2 km
2000
Kitchener-Waterloo Road Network
Greenbrook Well Field
2 km
Regional Supply Well G5
400
Legend
Sodium Concentration
Chloride Concentration
350
300
mg/L
250
ODWS for Chloride
‘94
200
‘98
ODWS for Sodium
150
100
50
0
72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06 08
Year
Continuous Coring
Well Installation
Application of Bromide Tracer
Road Shoulder Profiles
GB1-01
(10 October-2001)
(10 October-2001)
GB1-01
(10 October-2001)
GB1-01
(10 October-2001)
Subsurface Lithology
Moisture Content (%)
Chloride Conc (m g/kg)
Porew ater [Cl] (m g/L)
GB1-01
0
0
Sand Silt
5
10
15
20
0
500
1000
1500
0
0
0
0
1
1
1
2
2
2
5000 10000 15000
Fine Sand
1
3
Fine Sand
4
5
6
Sand
Till
3
4
3
4
Depth (m BGS)
Silty Sand
Depth (m BGS)
Depth (m BGS)
2
Depth (m BGS)
Sand
3
4
5
5
5
6
6
6
M Sand
Sand
Sarwar et al. 2002
Water
Table
Well
Screen
Water Table
Porewater Chloride Concentration (mg/L)
1200
GB1-01
GB4-01
GB2-01
GB5-01
GB3-01
1000
800
600
400
200
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Perpendicular Distance from Curb (m)
Source Width
Repeat Chloride
Profiling
Sarwar et al. 2002
3.5
Winter Maintenance and Parking Lots
and Sidewalks
Over application of salt
• Expectations of property owners for bare pavement
• Lack of understanding of how deicers function
• Fear of litigation
Improper drainage from buildings
Location of snow storage related to excessive salt application
(Photograph by Bob Hodgins)
Good example of snow storage (Photograph by Bob Hodgins)
Poor condition of pavement promotes loss of chloride
by infiltration to the subsurface.
(Photograph by Bob Hodgins)
Winter Parking Lot and Sidewalk Maintenance
• Deicers melt snow and ice but provide no traction
• Anti-icing prevents the bond forming between pavement and ice
• Deicing works best if you plow before applying material
• Pick the right material for the pavement temperature
• Sand only works on top of snow as traction – provides no melting
• Anti-icing chemicals must be applied before snowfall
• Road salt does not work at temperatures < 15 º F
Melt times for salt (NaCl )
at different pavement temperatures
Melting Characteristics
Variables affecting application rates
Increase rate if
• compaction occurs and cannot be mechanically removed
• too much snow left behind
Decrease rate if
• light snow on freezing rain
• pavement temperature is rising
• subsequent applications
Clarkson Go Station Parking Lot Study
Mountain Organic Natural
Icemelter (~0.01 to 0.14 kg m-2)
4 t of common road salt typically
applied (~0.2 kgm-2) per event ~
10 x the rate used on provincial
roads
GO 1
GO3
Conclusions
• The hydrologic response from both parking lots was flashy and tightly
coupled with the type and amount of precipitation inputs as well as the
specific processes that induced the melt (i.e. chemical melt versus
temperature induced melt).
• The maximum discharge was 50 Ls-1 and 82 Ls-1 for the GO1 and GO 3
parking lots, respectively.
• The event mean chloride concentration for the 26 monitored events was
14,561 mg L-1 and 6,816 mg L-1 for the GO 1 and GO 3 parking lots,
respectively.
• However, average chloride loads (g m-2) were higher by a factor of 2.3
for GO 1 (46 gm-2) compared to GO 3 (20 gm-2).
Leanne Lobe
October 15/07
Salt Reduction Initiatives
• Parking Lots and Sidewalks
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–
–
–
–
–
Surveys
Barrier Analysis
Pilot studies
Guide to Salt Management
Self-assessment Tool
Salt Management Workshop
• Sometimes less really is more
• Safety is a priority
• Building partnerships
• Engaging the stakeholders
• Overcoming the barriers
• Identifying the motivators
Designation Process
Registered
Certified
Snow Removal
Contractor
Professional
3 Years
Company and/or
Facility
Smart about Salt - Benefits
• Insurance advantages
• Access to data
• Marketing opportunities
• Program efficiency
• Environmental stewardship
• Leadership
Barriers to Implementation!
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•
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•
•
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•
•
•
Lack of stakeholder interest/commitment
Lack of means
Lack of awareness and access to information
Dynamics of enforcement
Overcoming history and lack of experience
Lack of incentives for adoption of new technologies/actions
Inability to adapt
Uncontrollable external circumstances
Degree and speed of change
Clean Water Act
• Introduced in 2005 and passed in 2006
• To protect existing and future drinking waters in
order to protect and enhance human and
ecosystem health
• SWP represents first barrier in multi-barrier
approach to providing safe and sustained water
supplies
Requirements of the Clean Water Act
Create Source Protection Committees (SPC) to
1. Define source protection area
2. Identify potential threats
3. Take action to prevent threats from becoming
significant
4. Require public participation on every local SWP
Plan
5. Plans and actions be based on science
Clean Water Act Focus
• Reduce significant risks to drinking water
Municipal water sources
• Vulnerable areas
Wellhead protection areas
Intake protection areas
Highly vulnerable areas
• Plans to reduce significant risks to accept able
levels and prevent future significant risks
Intake Protection Zones (IPZ)
Vulnerability
• Closer to intake – increase the vulnerability to risk
• Zone 1 – minimum 1 km radius
• Zone 2 – minimum 2 hr travel time to intake
Potential Threats
•
•
•
•
•
Oil and gas
Aggregate extraction
Storage tanks
Chemical use
Mines and mine
tailings
• Contaminated sites
• Waste disposal sites
• Pesticides
• Hazardous industrial
wastes
• Bio-solids
• Septic tanks
• Stormwater
• Wastewater
• Land drainage
• Road salt
Listed in Section 1.1 of Ontario Regulation 287/07
Implications of SWP for Road Salt
Management
1.
2.
3.
4.
5.
6.
Improved design and delivery of parking lot winter
maintenance programs
Increased adoption of new technology
Improved delineation of salt vulnerable areas and refined
winter maintenance procedures in IPZs.
Increased level of training (certification) for road
authorities and private contractors
Integration of salt management plans with SPCs objectives
to delineate source waters, identify threats and develop
and implement SWP Plan
Improved stormwater management practices