Post on 22-Dec-2015
Winter maintenance, chlorides and parking lots: Managing more with less!
Dr. M. StoneDepartment of Geography and Environmental
Management University of Waterloo
Partnering for Snow Management Success
2010 Snow and Ice SymposiumMississauga, 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:• Season• Road type/class• Snow clearing practices• Drainage infrastructure• Subsurface geology• Lawn watering
Groundwater Transport
Run-off
Background deposition
W indSplash
Spray
PO T 406
R U M 32 9
Highly spatially and temporallytemporally 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 Management7 Design and Operation of Road Maintenance Yards8 Snow Storage and Disposal9 Winter Maintenance Equipment and Technologies
http://www.tac-atc.ca/english/resourcecentre/roadsalt.cfm
Historical ContextAssumption:
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
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
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.
Source: Mullaney et al (2009) USGS Scientific
Investigations Report 2009–5086.
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
Mullaney et al (2009) U.S. Geological Survey Scientific Investigations Report 2009–5086, 41 p.
Maximum Cl levels in NE US
Historical Salt Loading Region of Waterloo
CAMBRIDGE
NORTHDUMFRIES
KITCHENER
WOOLWICH
WELLESLEY
WILMOT
WATERLOO
Sensitivity 1
Sensitivity 2
Sensitivity 3
Sensitivity 4
WHPA to be Revised
SENSITIVITY AREAS
WELLHEAD PROTECTION SENSITIVITY AREAS
Municipal Wells
Greenbrook Well Field
0 5km
CAMBRIDGE
NORTHDUMFRIES
KITCHENER
WOOLWICH
WELLESLEY
WILMOT
WATERLOO
Sensitivity 1
Sensitivity 2
Sensitivity 3
Sensitivity 4
WHPA to be Revised
SENSITIVITY AREAS
WELLHEAD PROTECTION SENSITIVITY AREAS
Municipal Wells
Greenbrook Well Field
WestEast
0 5km
Waterloo MoraineWaterloo Moraine
Paul Martin, WHI
Nith RiverGrand River
Nith River
0 10 km
Greenbrook Well FieldGreenbrook Well Field
K6K3 K4B
K1
K2
K5
K8
• 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.
10 year capture zone
0 1 km
Chloride Concentration at the Chloride Concentration at the Greenbrook Well FieldGreenbrook Well Field
Year
Ch
lori
de
(mg
/L)
1960 1970 1980 1990 20000
100
200
300
400
drinking water limit
K3
K5
K1
K4b
K2
19501950
2 km
Kitchener-Waterloo Road NetworkKitchener-Waterloo Road Network
Greenbrook Well Field
20002000
2 km
Kitchener-Waterloo Road NetworkKitchener-Waterloo Road Network
Greenbrook Well Field
72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06 08Year
0
50
100
150
200
250
300
350
400
mg
/L
LegendS o d iu m Co n ce n tra tio n
Ch lo rid e Co n ce n tra tio n
Regional Supply W ell G5
ODW S for Chloride
ODW S for Sodium‘94
‘98
Continuous CoringContinuous Coring
Well InstallationWell Installation
Application of Bromide TracerApplication of Bromide Tracer
Sarwar et al. 2002
0
1
2
3
4
5
6
0 500 1000 1500
De
pth
(m
BG
S)
GB1-01(10 October-2001)
Chloride Conc (mg/kg)
0
1
2
3
4
5
6
0 5 10 15 20
De
pth
(m
BG
S)
GB1-01
(10 October-2001)
Moisture Content (%)
0
1
2
3
4
5
6
De
pth
(m
BG
S)
Sand Silt
Fine Sand
Sand
Silty Sand
Sand
Till
M Sand
Sand
Fine Sand
GB1-01(10 October-2001)
Subsurface Lithology
0
1
2
3
4
5
6
0 5000 10000 15000
De
pth
(m
BG
S)
GB1-01(10 October-2001)
Porewater [Cl] (mg/L)
Water Water TableTable
Road Shoulder ProfilesRoad Shoulder Profiles
Well Well ScreenScreen
Sarwar et al. 2002
Monitoring Site GB5-01at Hgwy 7 & 8
0
1
2
3
4
5
6
7
8
0 4000 8000 12000
Chloride Concentration (mg/L)
December
April
Repeat ChlorideRepeat ChlorideProfilingProfiling
Water Table
0
200
400
600
800
1000
1200
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Perpendicular Distance from Curb (m)P
ore
wa
ter
Ch
lori
de
Co
nc
en
tra
tio
n (
mg
/L) GB1-01 GB2-01 GB3-01
GB4-01 GB5-01
Source Width
Winter Maintenance and Parking Lotsand 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)
• 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
Winter Parking Lot and Sidewalk Maintenance
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
4 t of common road salt typically applied (~0.2 kgm-2) per event ~ 10 x the rate used on provincial roads
Mountain Organic Natural Icemelter (~0.01 to 0.14 kg m-2)
GO 1 GO3
• 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).
Conclusions
Leanne LobeOctober 15/07
Salt Reduction Initiatives
• Parking Lots and Sidewalks– 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
ProfessionalCertified
Company and/orFacility
Snow RemovalContractor
Registered 3 Y
ears
Smart about Salt - Benefits
• Insurance advantages
• Access to data
• Marketing opportunities
• Program efficiency
• Environmental stewardship
• Leadership
Barriers to Implementation!
• 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
1. Define source protection area2. Identify potential threats3. Take action to prevent threats from becoming
significant4. Require public participation on every local SWP
Plan5. Plans and actions be based on science
Create Source Protection Committees (SPC) to
Clean Water Act Focus
• Reduce significant risks to drinking waterMunicipal water sources
• Vulnerable areasWellhead protection areasIntake protection areasHighly 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. Improved design and delivery of parking lot winter maintenance programs
2. Increased adoption of new technology3. Improved delineation of salt vulnerable areas and refined
winter maintenance procedures in IPZs.4. Increased level of training (certification) for road
authorities and private contractors5. Integration of salt management plans with SPCs objectives
to delineate source waters, identify threats and develop and implement SWP Plan
6. Improved stormwater management practices