When Colby Pond was originally surveyed it was much larger and deeper, but since the failure of the old rock dam this pond has become more of a bog. Bog-type plants ring the shoreline and are very numerous. In 1981, biologists visited the pond to update water quality information and found it difficult to reach the water. At that time maximum depth was only 3 feet. Colby Pond is now only a ‘wide spot’ in the stream.