Being on the water in Colorado is great fun, but it also presents the possibility of danger for river enthusiasts. Colorado has more than a thousand of these river structures and if you're going to be on the water it's important to know where they are. What Is A Low Head Dam? You'll see these structures that are built into and across streams and rivers. These engineered structures are put in place to divert water to support water usage, and in some cases to provide recreational opportunities for boating, rafting, and tubing. We have seen these popping up in western Colorado.