Data from DPW in Baltimore is either in enormous sets of text only files or 404 when trying to view mapping. But I did manage to pull this together after 13 hours of headache staying up overnight the entire night last night. Flow speed and direction is inferred from a lidar elevation dataset, so some directions aren't true to all drains, but it's close enough for me. If I feel like doing something as ridiculous and painful as this again, I'll try to do another city, and I will post the link here, but for now, this is proof of concept. I will probably want to do another city with a LOT of walkable drains like Baltimore. Leave requests in comments.