The importance of good tracking pads

Below: Trackout from just 1 vehicle, 1 trip, at a construction site.

Muddy tracks aren't a question of appearance--often they are nearly invisible.

Muddy tracks you can see are just the tip of the iceberg.

If you can see any tracks at all, then you can bet there are tons of mud washing into our lakes from this construction site (see calculations below).  

When contractors sweep at all, it's usually just around the construction entrance.  But that's not enough--because the bulk of the mud is dropped beyond the sweeping distance.

Upper left: Tracks by north entrance about noon. Click on photo to enlarge.

Upper right: Same area at quitting time.  Different tracks indicate there was an earlier sweeping, but not late enough to remove all the tracks before another rainstorm after work.

Bottom left: Faint tracks & small clods on Gately Ter, 4 blocks away.

Nine tons of sediment from Sequoia Commons construction

The calculations below are guesses, needing much refinement.  The purpose is simply to show how mud on tires can really add up.

Each tire (right) easily carries 10 pounds of mud

• Assume construction takes 1 year, 5 days a week for 52 weeks.  Assume that only half of those days have mud on-site (rain is less frequent--but mud persists for a while).  This gives 130 days a year when mud might be tracked off-site.
• Assume each day, on average, 10 visits of vehicles with large wheels, 6 wheels per vehicle (concrete tucks have more tires).  Assume each wheel can track 2 lbs of mud off-site.  Total, 12 lbs mud per visit or 120 lbs per day.
• Assume each day 20 visits by smaller vehicles like pickup trucks, with 4 wheels.  Each vehicle tracks a total of 1 lb mud off site.  Total, 20 lbs per day.

The total mud tracked per day is 140 lbs X 130 days, for a grand total of over 18,000 lbs/year, or 9 tons.

How can so much mud be tracked out, when you can barely see the tracks?  Simple--it's miles before all the mud drops off the tires.  It's spread so thinly across the roads you can barely see it.  But it still winds up in the lake.  After a rain storm in June, I followed one muddy track for six miles.

Yahara Materials--Every truck trip has two polluting ends.

Double trouble--the other end of the trip

The traffic from s construction site is visiting another location where muddy tracks can occur.

For example gravel comes from Yahara Materials, the Meinholz Quarry #7.  This quarry has multiple violations of erosion control laws, including muddy tracks, no gravel tracking pad, and ineffective sediment fences.  So in effect, you can multiply the 9 tons above by 2--to account for the sediment at each end of a vehicle trip.




What's really needed is a system of high-pressure water sprays to clean wheels before trucks leave the site.

Cleaning tires--
it's not rocket science.

My mother taught me to wipe my feet before I came in the house.  So why can't trucks leaving construction sites wipe their feet before they track muddy footprints into the lakes?

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