That looks like a line to the drain field. They need the slope. The drain lines with holes in them should be level. Don't want it all to flow to the end of the system and work backwards. At least here that's how it works.... And here we put the black Poly half rounds over the drain pipe, Lets it have air space above, not putting dirty sand whatever right on the pipe.....
Heres a vid on how I have seen it done here..
http://www.youtube.com/watch?v=0zErJggaBRk

Realist - Everybody in America is soft, and hates conflict. The cure for this, both in politics and social life, is the same -- hardihood. Give them raw truth.