river stones to redirect rainwater runoff to drains?

Hey all - my previous owner installed two 1x1 foot box ground drains near the back of my house. They run off underground through that 6-8 inch black corrugated tubing into a ditch 75 feet away. I can flood them with a hose - they work fine.

However, the grading in this general area has become poor, and water is running away from them instead of into them. It's also an area we walk through a lot, and it gets boggy. Plus, I also have a septic system. Although one field is about 20 feet from this area, I also want to avoid any more water going into the ground.

For decorative reasons as much as runoff reasons, I've been thinking of laying flat river stones in the area, making a sort of patio area. I'd position them to shoot water towards the drains.

I don't really have the cash to lay them in cement or do a "real" patio. I was thinking I'd just put them together like a puzzle, laying them on the ground. But there would be natural gaps between the stones. I suppose I could fill them with sand. But won't water just wash that away, and thus, might I be back to almost where I started with water still going into the ground?