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