I am working on a project that analyzes the correlation between land use and food web connectance of aquatic invertebrates in certain streams. In order to accurately analyze the data, I was planning on dividing the streams into four parts based on the length: 500 meters, 1000 meters, 1500 meters, and 2000 meters. I converted the polylines of the streams into rasters so that the distance in meters can be accounted for, but I'm not too sure how to divide these into measured segments. I tried clipping them to buffer rings, but because the streams are not straight, the length of the segments are not exact. Is there a tool I'm overlooking?