I am currently working on a hydrology project where I am trying to break a stream network into 250m segments. The problem is that the streams are not all adjacent, as I have clipped the NHD file to include only perennial streams in my watershed. What I have been doing is taking these different, unconnected line features and merging them into one stream using editor. I then have been using the "divide line by length" add in found here: http://www.arcgis.com/home/item.html?id=d5d27ee47330434b9a96b91136a0118f.
What this tool is doing however is spliting the whole set into 250m segments, but not necessarily keeping the new segments adjacent to each other. The tool is combining segments that do not measure up to 250m with portions of other lines that also do not add up, but on totally unconnected streams.
I have also tried to use the split tool in editor. I have been splitting by distance (250m), but it is only creating one new feature of that length, not breaking it up the entire merged stream.