How Does Sidewalk Salt Affect Stormwater?
There are many different types of deicers, commonly called road salt, and typically contain chloride (the melting component). One teaspoon of salt can permanently pollute 5 gallons of water, so it is important to use deicers as directed and as sparingly as possible. Salts change the ecosystem of our waterways, negatively impacting the quality of our drinking water, and can create many adverse reactions with our wildlife and aquatic life. Salt also has tremendous infrastructure impacts due to its corrosive nature. To help keep our community safe and healthy, here are a few tips for salt application from the MN Pollution Control Agency (check out the Winter Parking Lot and Sidewalk Maintenance Manual for more information):
- Early snow removal is vital to avoid snow compaction and prevent icy build-up – deicers work most effectively on cleared areas as they can only melt a small amount of ice
- Deicers do not work effectively in extreme cold temperatures – for below freezing days, use sand, this will offer traction when the temps are too cold for melting
- Once sand moves to bare pavement, it should be swept up – it is only effective on top of ice and sweeping the sand will prevent slippery messes when ice reforms and prevent it from being tracked around (swept sand can be reused on compacted or other icy areas!)
- A small amount of deicer goes a long way – if you have over salted or spilled, sweep up clusters and re-use in other areas
- In general, salt application should be about 4 lbs of deicer, or less, per 1000 sq ft (1 heaping coffee mug is about 1 lb of deicer) – an easy way to measure your area is to go on Google Maps and look at the aerial, right-click on the map to select measure distance, and trace your surface shape, connecting both ends, this will give you the area of that shape (or walk out your area and use your steps to estimate: length x width = square feet)
- A good spread pattern for deicer will not have overlapping or clumps of salt, and will have granules spaced about 3 inches apart, but be sure to check your application rate chart for your deicer to get the best distribution amount
What Is Stormwater Runoff?
When it rains, water that does not soak into the ground becomes runoff. This runoff collects pollutants from our properties such as vehicle residues, lawn fertilizers, property remodeling, and pet feces, and drains into our stormwater system.
The polluted runoff is NOT treated after it goes into street drains and goes straight to our rivers and lakes, impacting our drinking water, swimming, fishing, and can turn our waters into a stinky, brown-green mess.
How Can We Keep Our Waters Healthier?
You can make a huge impact on local waters just by being aware of what’s coming off of their yard! The City of Cambridge encourages our community to help protect our waterways. View the categories below to learn what you can do in your home to make a difference:
Managing Stormwater Runoff
The illustrations below show how construction and landscaping play a role in managing runoff.
Keep a Lookout for Illicit Discharge
Do you see something suspicious being sent down our storm drains? Nothing other than rain water should be going into City storm drains, anything else could be illicit discharge! Please report activity or call (763) 689-1800 if you see anyone dumping down drains, or if you see suspicious colors, smells, or materials getting into or coming out of drains!
For more information and common FAQs on Illicit Discharge, watch the video below.