Also, these are very old culverts under an interstate highway that have been extended over the years, and one in particular was originally a brick arch section that has been extended on one end with a conc. box section, and on the other end with a pipe section. To further complicate things, there is also a 40 degree bend at one of the transition sections.
The programs that I have used, HY-8, culvertmaster, etc. do not allow for multiple barrel sections and significant bends. If someone has dealt with these problems before I would really like to hear from them.