university of wisconsin – madison department of...
TRANSCRIPT
10/12/2012
1
Managing Winter Maintenance Environmental Impacts
University of Wisconsin – MadisonDepartment of Engineering Professional Development
© 2012 Board of Regents ‐ University of Wisconsin System. All Rights Reserved
Benjamin J. Jordan P.E., Program Director
University of Wisconsin ‐Madison
Department of Engineering Professional
Development
432 N. Lake St , Room 717
Madison, WI 53706
(608) 265‐4478
[email protected]://tic.engr.wisc.edu/http://epd.engr.wisc.edu/
10/12/2012
2
What we will discuss in this session
• This session is focused on the impacts of winter maintenance operations on the natural environment – air, water, plants and soils.
• The session does not include discussion of impacts on the built environment –corrosion, concrete damage, etc.
Environmental Concerns from Winter Maintenance Operations
• Air Pollution
– Vehicle exhaust
– Dust
• Damage to plants and soils
• Water Pollution
– Runoff• Chlorides
• Nutrients
10/12/2012
3
Consider Environmental Concerns in the Planning and Management of Winter
Operations ‐ Air Pollution
• Vehicle routing– Is vehicle routing optimized to save time and fuel and reduce pollution?
• Idling policies– Excessive idling wastes fuel and pollutes the air. Is there a vehicle idling reduction policy?
• Alternative Fuels– Can alternative fuels be utilized?
• Small engines– Small engines can produce significant pollution. Are older snow blowers and other small equipment be replaced with new cleaner burning equipment? Are engines kept tuned?
10/12/2012
4
Air Quality Impacts of Sand
• Sand can increase particulate air pollution (pm10)
• Use clean washed sand with minimal <#50 material
• Sweep up excess sand
Consider Environmental Concerns in the Planning and Management of Winter
Operations ‐Water � Pollution
• Snow storage and disposal
–Do you plan onsite snow storage to minimize environmental impact ?
–Do you plan snow removal and disposal to minimize environmental impacts?
10/12/2012
5
Consider Environmental Concerns in the Planning and Management of Winter
Operations ‐Water Pollution
• Deicing chemicals– Are salt and other deicing chemicals managed to minimize the amount used?
– Do chemical storage, transportation and application practices minimize potential environmental impacts?
– Are procedures and employee training in place to minimize environmental impacts?
What is the greenest tool in your winter maintenance toolbox?
10/12/2012
6
What is the greenest tool in your winter maintenance toolbox?
10/12/2012
7
Source: LIVING SNOW FENCESMichigan CONSERVATION RESERVE PROGRAM CRP – CP17AUSDA Natural Resources Conservation Service (NRCS) March 2011
10/12/2012
8
ENVIRONMENTAL IMPACTS OF DEICING CHEMICALS ON THE ENVIRONMENT
• Plants
• Soils
• Water Resources
Plants
• Salt solutions can disturb water uptake of roots and cells in leaves
• Salt spray can dry out leaves
10/12/2012
9
Deicer damage to plants
‐ late winter season applications can cause the most damage.
‐ On most damage occurs within 30‐50 feet of the road ‐more severe on the downwind side.
‐ susceptibility to chloride damage varies significantly between species.
PLANTS
Damage can be reduced by:‐ decreasing application rate‐ prewetting the deicer‐ using different deicer‐ using equipment that better
controls where material is placed
‐ planting salt resistant plants
Photo sources: Purdue Plant & Pest Diagnostic Laboratory http://www.ppdl.purdue.edu/PPDL/weeklypics/1‐22‐07.html,
10/12/2012
10
Reducing impacts on plants
Use different equipment
Photo sources: EPOKE, Ossian, Earthway
Reducing impacts on plants
Use different equipment
10/12/2012
11
Use different materials
• Blends with potassium chloride
• Blends with urea
• CMA
• Magnesium Chloride
Soil
• The sodium ion from salt will raise the pH of soil and the soil becomes muddy and denser.
• Chloride ion is not adsorbed on soils but it can form complexes with heavy metals in the soil, releasing them into the environment.
• Higher concentrations of salt may develop near the pavement edge during the winter.
• Concentrations decrease during the spring and summer.
10/12/2012
12
Impacts of Chlorides on Plants and Soils
Alternative deicers containing chloride
(MgCl, CaCl, Blends) have environmental effects similar to that of salt
Source: USEPA
Soil and Plant Impacts of Alternatives
CMA SandSoils Ca and Mg can exchange
with heavy metals. Ca increases soil aeration and permeability
Gradually will accumulate in soil
Vegetation Little effect Can accumulate on and around low vegetation, causing stress
Source: USEPA
10/12/2012
13
Impact on Water Resources
USEPA national chronic freshwater‐quality standard for chloride:
230 mg/l
= 1 teaspoon salt in 5gallons water
10/12/2012
14
USEPA national acute freshwater‐quality criterion:
860mg/l
about 1 Tablespoon of salt in 5 gallons of water
Impacts of Road Salt on Water Resources
Groundwater Mobile Na and Cl ions readily reach groundwater and concentration levels can increase temporarily in areas of low flow during spring thaws. Shallow wells near roadways are most vulnerable.
Surface water Can cause density stratification in small lakes having closed basins, potentially leading to anoxia in lake bottoms.
Aquatic biota No effect in large or flowing bodies at amounts expected from current road salting practices. Small streams that are endpoints for runoff can receive harmful concentrations of Cl. Cl from NaCl is generally not toxic until it reaches levels of 1,000-36,000 ppm.
Source: USEPA
Low Oxygen Levels
Plants and Animals that livein water
10/12/2012
15
Chloride accumulation in lakes
Examples of significant, long-term increases in baseline concentration of chloride for streams and rivers of the northeastern United States.
Kaushal S S et al. PNAS 2005;102:13517-13520
©2005 by National Academy of Sciences
10/12/2012
16
Effects of Highway Deicing Chemicals on Shallow Unconsolidated Aquifers in Ohio—Final ReportBy Allison E. Kunze and Bernard N. Sroka. Scientific Investigations Report 2004‐5150U.S. Department of the Interior, U.S. Geological Survey
Road
EPA’s Secondary MCL for Chloride in drinking water 250
Effects of Deicing Salt on Drinking Water Wells
Effects of Deicing Salt on Drinking Water Wells
10/12/2012
17
Chloride concentrations in 366 out of 6,227 wells sampled in Oakland County exceeded the SMCL of 250 mg/L.
Source: Arsenic, Nitrate, and Chloride in Groundwater, Oakland County, Michigan U.S. Department of the InteriorU.S. Geological SurveyFact Sheet 2004-3120October 2004
Anti‐caking agents in Salt
Prussian blue - ferric-ferrocyanide(Fe4 [Fe(CN)6 ] 3 contains 54.5% cyanide )
Yellow Prussiate of Soda – Sodium Ferrocyanide(Na4Fe(CN)6, contains 51.36 % cyanide)Approved by the FDA as a Food Grade Anti-Caking Agent
10/12/2012
18
10/12/2012
19
Environmental Impacts of CMA and Sand on Water
CMA Sand
Groundwater Ca and Mg can release heavy metals from the soil into groundwater
No known effect
Surface water Can deplete oxygen in small lakes and streams when degrading
No known effect
Aquatic biota Can cause oxygen depletion, leading to anoxic conditions
Particles settling to stream bottoms degrade habitat
Source: USEPA
Ag‐byproduct Deicer Impacts
• Potential for oxygen depletion through biological oxygen demand (BOD) at concentrations greater than 100 ppm in ponds and lakes
• Potential for nutrient enrichment of surface waters exposed to high concentrations of deicers derived from agricultural products
(see information provided on phosphorus content of various deicers)
Source: USEPA
10/12/2012
20
Effect of nutrients on surface waters
Source: USEPA
10/12/2012
21
10/12/2012
22
If all deicers have environmental impacts, why do we focus on salt?
• NaCl salt is by far the most used deicer
• For salt to work, it must dissolved in solution with water
• The salt solution contributes to the total dissolved solids in stormwater runoff.
Dissolved Solids
• Dissolved solids are much more difficult to remove than suspended solids.
• Dissolved solids can be removed by evaporation, distillation or membrane filtration
• Stormwater management practices remove suspended solids , but do very little to remove dissolved solids
10/12/2012
23
Michigan Municipal Stormwater General Permit Language
• Salt and sand applied for improved traction shall be prevented from entering MS4s and receiving streams to the maximum extent practicable.
• Good housekeeping shall be required at salt and sand storage facilities to prevent the discharge of salt and sand from these areas.
• The permittee shall also comply with the salt storage requirements of the Part 5 Rules (Rules 324.2001 to 324.2009 of the Michigan Administrative Code)
Stormwater General Permit Language ‐Wisconsin
• If road salt or other deicers are applied by the permittee, no more shall be applied than necessary to maintain public safety.
• Note: The DOT “Highway Maintenance Manual”, chapter 35, contains guidance on application of road salt and other deicers that can be used to determine whether not application is necessary and what application rate is appropriate for deicing and ice prevention.
10/12/2012
24
10/12/2012
25
10/12/2012
26
ADIRONDACK COUNCIL WITHDRAWS LAWSUIT THREATAFTER VILLAGE OF SARANAC LAKE SIGNS SAL T-PILE CONSENT ORDER
Village Agrees to Road Salt Storage Cleanup at Colby Brook, State Imposes Fine
Just days after the Adirondack Council filed its notice threatening a suit in federal court, the NYS Department of Environmental Conservation issued a “Consent Order” to the village, setting a cleanup schedule. That order requires the village to take action by October 1. It also imposes a $5,000 fine, which the DEC agreed to cut to $1,500 if the work is completed in a timely way.
This incident should be a wake‐up call to other municipalities in the Adirondack Park that have neglected their obligations to cover their road salt storage piles,” Houseal said. “We have already received a number of phone calls from people in other villages and towns whose lakes, streams and underground drinking water are being ruined by road salt. We fully intend to press similar complaints wherever they are merited. This was by no means an isolated incident.
10/12/2012
27
“We also recognize that the State Department of Transportation (DOT) has become a major influence on the current problem by requiring the use of road salt on our highways,” Houseal explained. “We believe DOT could play a much more constructive role, by providing funds to local governments for salt‐storage buildings, and by sharing DOT shed space with local communities’ highway departments throughout the Adirondack Park. “We will press DOT to assist the Park’s communities in preventing salt contamination any way it can, including the development of non‐salt alternatives for deicing highways,” he said.
Houseal noted that the Adirondack Council’s February 2009 report Low Sodium Diet: Curbing New York’s Appetite for Road Salt (available for free at 518‐873‐2240 or www.adirondackcouncil.org) had resulted in a flood of responses from around the Adirondack Park, from people who have been trying to get their local governments to reduce salt use and to store road salt stockpiles more responsibly.
Implement Good Salt Management Practices
10/12/2012
28
Salt Management Practices
• Train staff to use only the minimum salt necessary. Prevent excessive salt use.
• Use mechanical means (Plowing) as much as practical to remove snow from the pavement surface
Spreader Controls
Ideally spreader controls should:
• automatically adjust for ground speed
• track material usage
Need to train drivers not to “turn it up to 11” or overuse the “blast” button.
10/12/2012
29
Salt Management Practices
• enclose salt storage • practice good housekeeping around salt delivery/loading areas
• contain runoff from post storm vehicle washing
What do you/what don’t you like about this Salt Storage?
10/12/2012
30
For details on Michigan requirements for Salt and Brine
Storage:• SALT AND BRINE STORAGE GUIDANCE FOR ROAD
AGENCY MAINTENANCE AND OTHER FACILITIES
http://www.michigan.gov/documents/deq/deq‐ess‐p2tas‐bulksaltbrineguidance_267024_7.pdf
• GUIDE TO SALT STORAGE REQUIREMENTS FOR SMALL COMMERCIAL SNOW REMOVAL SERVICES
http://www.michigan.gov/documents/deq/deq‐ess‐p2tas‐commercialsaltguidance_267027_7.pdf
Salt Management Practices
• Establish buffer zones and filter strips on the sides of the pavement in environmentally sensitive areas to limit direct spray reaching sensitive vegetation
• Buffer zones will settle some suspended solids and can also reduce runoff intensity potentially reducing the peak in chlorides that reach the surface waters.
• consider alternative chemicals for salt‐sensitive areas.
10/12/2012
31
Understand the capabilities and limitations of your deicing chemicals and train
operators to:
• Know the effective pavement temperature range of the chemical
• Know the recommended application rates
• Understand the when and how it is best to apply the material
• Understand when not to apply the material
Benjamin J. Jordan P.E., Program Director
University of Wisconsin ‐Madison
Department of Engineering Professional
Development
432 N. Lake St , Room 717
Madison, WI 53706
(608) 265‐4478
[email protected]://tic.engr.wisc.edu/http://epd.engr.wisc.edu/