Fred Koch, second from right, talks with Lauren Olson, right, the education and outreach coordinator of the Lake Auburn Watershed Protection Commission during a Watershed Walk and Talk on the Whitman Spring Trail in North Auburn on Monday afternoon. Behind them, from left, are Paula Curtis-Everett, Rick Speer and Dan Bilodeau. The group looked at an armored swale, which is a smoothed gully lined with porous cloth, riprap and a pool to allow sediment to settle. The overflow passes through a culvert and into another pool to remove more sediment, all in an effort to slow the water flowing downhill to prevent erosion and keep debris out of Lake Auburn. (Andree Kehn/Sun Journal)