Salt Snapshot Protocol Guidance Manual
This manual is a step by step introduction to how to conduct a “salt snapshot”. A snapshot is a short duration (a few hours) sampling event that captures samples from many locations in your watershed. The samples are then brought to a central location for analysis and recording.
If you don’t know what a Salt Snapshot is, read on.
LLWS “Salt Snapshot” Project - Measuring Summer Salt Concentrations in our Streams
In 2023, LLWS became aware of excessive salt use and decided to monitor the long-term effects of salt in the Little Lehigh watershed. We conducted a “Salt Snapshot” event in August 2023. In one day we tested water from 45 sites throughout our watershed. The sampling took place in a three-hour period, when the streams were at base (low) flow. Summer sampling shows us how much salt is present year-round, because it is done at a time when the streams are only fed from groundwater aquifers.
We tested the samples for chloride and conductivity levels. What we found were levels of chloride above 50 milligrams per liter (mg/l) in 15 of the sampling sites. Locations with higher chloride levels were mainly sites in more developed areas of the watershed. Deicing products, even those labelled “safe” contain chlorides (sodium chloride (salt), magnesium chloride, etc.)
Clink to map of the LLWS August 2023 sampling sites. Click on each site to see chloride and conductivity levels:
https://padlet.com/latzgoj/salt-snapshot-locations-98sm31sxgb1kzx6q
We repeated the sampling in August 2024 and added 45 more sites along the Jordan Creek. (See results and discussion in next section.)
Summer, low flow, Chloride Levels in Little Lehigh Creek and Tributaries, 2024
The map on the right shows chloride concentrations (mg/L) in Little Lehigh Creek water as of August. Lehigh County, PA, is outlined in black. Chloride levels exceeding 30 mg/L typically indicate creeks affected year-round by winter salting. Levels above 50 mg/L are detrimental to sensitive aquatic organisms, which form the base of the creek's food web. Chloride concentrations ranged from 0 mg/L near Blue Mountain to 254 mg/L in Allentown on Trout Creek.
While levels vary, there is a noticeable trend of higher chloride concentrations with increased land development.
Measured chloride levels above 50 mg/liter are a problem. Exposure to chloride at these levels has been found by scientists to cause harm to aquatic life, including fish, amphibians, and invertebrates. These organisms are sensitive to changes in water chemistry, and elevated chloride levels can cause stress and stunted development at low levels and even lead to mortality in severe cases. Year-round exposure to the chloride from salting, even at quite low levels, can harm the biodiversity of our ecosystem.
There are also major concerns about the long-term effects of salt accumulation on our groundwater. Many people in our area depend on the aquifers for drinking water. People who are on very low sodium diets should not drink water with more than 20 mg/l of sodium according to the Environmental Protection Agency (EPA). Pollution of groundwater creates a huge problem for future generations. Once aquifers are contaminated with salt, it is impossible to clean them up, and desalination of drinking water is very costly.
Salt causes corrosion and infrastructure damage to metal structures. The EPA has estimated that road salt usage has cost us approximately $5 billion dollars in annual repairs to cars, trucks, roads, and bridges.
What Can You Do?
First of all, be aware of the quantity of salt that you apply to your driveway and sidewalks in wintertime. You can reduce the amount you need by shoveling regularly. When you apply the salt, use about 12 ounces for a 20-foot driveway, or 10 sidewalk paving squares. Sweep up any leftover salt.
Volunteer to help combat oversalting; click the button below. More voices on salt are needed.
Speak up when you notice excessive salt use in your community (work, school, places of worship, shopping areas). If you live in a development that uses a private contractor for winter maintenance, pay attention to how much road salt is being used, and if it appears to be excessive, bring it to the attention of your homeowners’ association.
What Municipalities Can Do
By using best management practices, it is possible for a municipality to reduce road salt usage by 50% and save taxpayers tens of thousands of dollars in materials and labor costs. Watch the documentary “The Road Map to Road Salt Reduction” to see how this was done in New York State:
https://salt.lakegeorgeassociation.org/
To find out more, use links to explore other Salt Resources.
Carey Institute of Ecosystem Studies – Road Salt: The problem, the Solution, and How to Get There
https://www.caryinstitute.org/sites/default/files/downloads/report_road_salt.pdf
Video: Salt Impacts on Water Quality – John Jackson, Stroud Water Research Center
https://www.youtube.com/watch?v=Of4hpuFzgn0
Izaak Walton League of America Salt Watch – What you can do
https://www.iwla.org/water/stream-monitoring/salt-watch/what-you-can-do
Trout Unlimited Valley Forge salt pollution webpage
https://www.valleyforgetu.org/resources/whitepapers/road-salt/
Take the Izaak Walton Leagues Salt Quiz to see what you have learned
https://www.iwla.org/water/stream-monitoring/salt-watch/saltwatchquiz