Many may think it’s a dam shame what has happened over the years to Lake Knickerbocker, which backs up to the Chattahoochee Golf Course north of downtown Gainesville. The earthen dam that spans East Lake Drive, built in the early 1950s and separating Knickerbocker from Lake Lanier, is feared unstable by those who live in the area. And a buildup of silt, estimated at 32,000 cubic yards in a survey completed about seven or eight years ago, has muddied the waters, cut off inlets and become something of an eyesore.