Is there a rumor you’ve heard that you would like to track down? Is there something in the city — like playground equipment or a pothole — that needs to be fixed? Rick Romano answers some of the mysteries of life in Wauwatosa and helps solve everyday problems.

Why are some sidewalks so pockmarked?

Issue: A resident wrote, “In my walks around (my neighborhood) and other places, I run across many pockmarks in the sidewalks.” Upon closer inspection, he added, “most are due to disintegrating pieces of seashell. What is the story behind this, and what would it take to reduce such holes in the future?”

Status: Those pockmarks may be the result of several circumstances, said City Engineer Bill Wehrley and Department of Public Works Director Dave Simpson.

The concrete mixture may be one cause. A concrete mixture with a high percentage of chert – defined as a porous aggregate (sand, gravel, or crushed stone) with lower resistance to weathering – can cause surface defects knows as “popouts” in exterior concrete applications.

Those popouts over times also could be caused by a contractor’s application process where a high amount of water is used in the finishing process.

A third cause is where a high amount of salt is used to melt winter’s ice and snow.

The city has a regular timetable of replacing defective sidewalks, concentrating on one area at a time combined with special attention of correcting specific tripping hazards throughout the municipality as needed.

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