The Department of Conservation and Recreation’s Division of Water Supply Protection (DWSP) routinely monitors the water quality of the groundwater, streams, and rivers that flow into the Wachusett Reservoir. DWSP has documented significant increases in the amount of salt in the reservoir; it is very difficult and costly to remove salt after it is introduced into an ecosystem. DWSP is committed to finding ways to reduce salt use in the Wachusett Reservoir, Quabbin Reservoir, Ware River, and Sudbury Reservoir watersheds.
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DCR Watershed System Salt Reduction
There have historically been temporary high amounts of salt (sodium chloride) in streams and rivers linked to winter snow and ice management. DWSP has recently found that the salt from these winter storms has built up over time and increases in chloride can now be seen in summer testing of groundwater and reservoir tributaries. These consistently high levels of salt can impact drinking water quality, treatment, and distribution.
Increased levels of chloride in surface water and groundwater can harm aquatic life, from large fish to microscopic plankton and algae. Excessive chlorides in groundwater during the usual low-flow summer months can change the chemistry of the reservoir’s water and impact how it is treated before it enters local pipes to individual homes and businesses.
DWSP has developed several approaches to meet the goal of reducing salt applications in the watershed system. DWSP is working with Departments of Public Works, Highway Departments, and MassDOT to come up with creative solutions to the problem of salt contamination.
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Education, Training and Outreach
Education and outreach to communities, other agencies, and individuals is critical to the success of reducing salt use and impacts on water resources. DWSP's efforts include:
- Collaborating with MWRA and the UMass Baystate Roads program to offer no-cost winter snow and ice operations training to watershed town DPW employees; the trainings have also included DCR and MWRA staff.
- Exchanging information and equipment with Massachusetts Department of Transportation (MassDOT) District 3, which has greatly benefited the DWSP winter program.
- Making presentations on chlorides to concerned parties, including Water Supply Protection Trust, MWRA's Water Supply Citizens Advisory Committee , MassDOT, and MassDOT contractors.
- Creating a poster for Wachusett Reservoir kiosks and other public sites.
- Producing an informational video in about the importance of road salt reduction.
Improve Data Collection
DWSP has expanded its water quality monitoring program to learn more about how chloride moves in the watershed. Groundwater monitoring was started in 2019 and currently includes monthly monitoring at eight wells. Results have revealed concerning levels of chlorides at some locations and provided initial information about patterns and sources of chloride in the watershed.
Real-time, continuous monitoring stations have been installed on several tributaries that will help calculate daily chloride loading estimates.
DWSP is documenting information on the amount of salt used by the watershed towns and MassDOT, as well as estimates of salt used on private parking lots.
Model Impact of Reducing Inputs
DWSP is working with UMass to research many complex water quality topics, including the fate of salt within the watershed system. The 2021 publication of “Long-term analysis of road salt loading and transport in a rural drinking water reservoir watershed” by Soper et al., found that measurable water quality improvements will only be realized with a sustained long-term decrease in the amount of salt applied to roads. UMass has begun work on modelling the potential impact of hypothetical reductions in salt applications to guide where to concentrate future salt reduction efforts.
A second outcome of the UMass research was the identification of the linear relationship between the percentage of paved surface and surface water conductivity (chloride). As paved surfaces reach 4% of a watershed, there is a very high probability that the EPA chronic threshold for Chloride (230 mg/L) for aquatic life criteria will be exceeded and there could be water supply distribution/delivery impacts. This work has now been incorporated into the DWSP land acquisition program when prioritizing purchases.
Upgrade DWSP Snow Removal Practices
DWSP has taken many steps to upgrade its own snow and ice operations.
After participating in the Baystate Roads snow and ice training, DWSP began pre-treating its roads with solid salt. This action resulted in an immediate reduction in the total amount of salt used and demonstrated the importance of pre-treatment before a winter storm.
The next step for further salt reduction is utilizing a liquid salt brine solution as a pretreatment before a winter storm. Brine serves as an anti-icing agent to prevent snow and ice from binding to the road surface, allowing for easier removal, fewer applications, and faster return to a clean paved surface. Reductions of up to 35% less salt applied per winter have been realized by programs moving from solid salt to the adoption of salt brine. DWSP has purchased a salt brine generator, walk along sidewalks brine sprayers, and a truck based brine sprayer to begin brine pre-treatment in the winter of 2022-2023.
Salt Use Reduction Grants
DWSP established a Salt Use Reduction Grant program in FY21. This 50/50 matching grant program makes funds of up to $20,000 available for the seven towns in the Wachusett Reservoir watershed to help with the purchase of new equipment that reduce the use of salt. More than $119,000 has been dispersed via nine grants awarded to date, including more than $36,000 in FY23. The grants have been used on two new salt storage facilities, flexible plow blades that remove snow and ice more effectively from uneven surfaces (which ultimately requires less salt to maintain the roadway), roadway temperature sensors in plow vehicles, and a portion of costs for a new salt brine generator.
FY23 Amount Distributed: $36,015
- Grant Amount: $10,000
- Grant Purpose: Purchase flexible plow blades to outfit five trucks. These flexible plow blades will improve the quality of snow removal thus reducing salt usage.
- Grant Amount: $3,428
- Grant Purpose: Upgrade one six-wheel dump truck plow and wing plow from a standard plow blade to a flexible system. This system will allow the truck to more thoroughly scrape roads to reduce the amount of salt needed on those roads.
- Grant Amount: $2,588
- Grant Purpose: Install an electric service to salt shed to install lighting. The lighting will allow operators better working conditions and result in an overall reduction in salt that is “lost” during loading operations. In the future, the installed electric service will be utilized for pumping of on-site stored liquid deicing materials.
- Grant Amount: $20,000
- Grant Purpose: Help with cost of purchasing a $150,000 brine making machine and storage tank setup for the new DPW Facility located at 18 Industrial Drive. This machine will allow the Town to produce and store its own brine anti-icing liquid for application on the Town’s roads prior to snow and ice events. The Town has previously purchased a brine applicator skid for a Highway Division truck, and purchasing of the brine making machine is the final step in allowing the Town to begin pre-storm brine application.
FY22 Amount Distributed: $24,553
- Grant Amount: $10,553
- Grant Purpose: Construction of residential salt/sand containment shed and purchase of flexible plow blades.
- Grant Amount: $ 14,000
- Grant Purpose: Purchase of carbide cutting edges for plows and wing plows for the Town’s medium duty trucks. Installation of 3- to 4-foot-long segments of straight carbide steel cutting edges will allow for a more flexible, but stronger cutting edge than those currently used by the Town, and thus provide more effective plowing event.
FY21 Amount Distributed: $58,592
- Grant Amount: $18,592
- Grant Purpose: Purchase of several items to reduce current DPW salt use.
- Flexible plow blades that follow irregular road surfaces, plow roads more effectively, and therefore reduce the amount of salt needed.
- A small salt spreader with controls to help reduce applications at town buildings and small areas.
- Temperature sensors for all plows to help decide when salt applications will be effective.
- Grant Amount: $20,000
- Grant Purpose: Purchase seven flexible, segmented plow blades for vehicles used in snow and ice operations. The use of this type of blade promotes better initial snow and ice removal during snow and ice operations and prevents bonding of ice to the pavement surface. It is easier to prevent snow and ice from bonding to the pavement surface by mechanical means than by attempting to melt it after the fact, so these types of blades have the potential to reduce overall salt usage.
- Grant Amount: $20,000
- Grant Purpose: Help offset the cost for the purchase and installation of a $75,000 salt storage shed. Large piles of sand and salt had been stored outdoors and runoff from this area has impacted a nearby tributary. Uncovered or poorly managed salt piles have been shown to be a fairly significant source of chloride contamination and moving these materials inside a new covered structure will have immediate benefits to water resources.