A few years back, a 100k sf warehouse development was contingent on a 100’ culvert expansion for a slow flowing, 20° stream on the edge of the parcel. To make it challenging, the stream happened to run under power lines, making it impossible to utilize a crane installing the concrete culverts. Over designed? Absolutely yes, but the $100k in time and materials still worked and conservation was happy. Construction permits were issued the site broke ground. Six weeks later 16 trucks arrive for delivery. Pumps and bypass systems have been running for weeks getting the stream dry and the base compacted. All while the entire conservation committee is watching over our shoulders. The project engineers start measuring the 32k lbs Headwall as it’s installed. Instantly rejected! We screwed up the orientation of the head walls, minimally changing the flow of the water into the culvert. After 2 full days of meetings with conservation, engineers, and vendors, we were able to keep the culvert but needed to add a sediment forebay, which is a a small, storage area designed to capture and settle sediment and debris from stormwater runoff. Every time I see 12” river rock in a sediment forebay I think about the $22k dollars in additional costs because a small communication mistake.