Why want two navigation bars?

Why want two navigation bars on one webpage? Well I'll tell you why, the reasons why I chose to have one main navigation bar at the top of my webpage and a secondary one at the bottom was because instead of the user scrolling all the way to the top of the page to access new content on another page, they can straight away access it, once they reach the bottom of the page using the secondary one. Is well I didn't want to apply an 'anchor' that takes you from the bottom of the page to the navigation bar at the top because it don't seem as professional as having a secondary navigation bar.