Question
I've lived in my home for about 9 years.  It is not a good
lot.  My house sits down from the road with a long slope
at about a 135 degree angle, I would guess about 30 feet
long.  Grass covered except for the wide wooden steps coming  down from the street under which is dirt.  I've had 4  mudslides when it rains HEAVY.  I also have a storm drain sitting  to the right of my steps on the street which cannot hold all the water when it rains massively, and therefore runs down my yard.  Yes, I've talked to my borough...you know how that goes-they built me a half baked curb and chipped out some asphalt around the drain.  So, the last one happened last week.  I now have about a 2 ft. deep trench under my steps where the water washes down from under.  What can I put there to help stop this.  A couple of people (not professionals) have suggested putting river rock down.  My question is, would this help and would the river rock come down in a massive rain?  When this happens the rains have come down hard enough to move some stray bricks under the steps, as well as lifting up and washing away large pavers from my sidewalk at the bottom of the steps.  Do you think this would be a good idea for a fix or would you have any other suggestions?  Thanks in advance for your input.

Answer
Water is extremely damaging when it flows, and if it really is smoking down a large incline (135 degrees?), lots of potentially destructive energy is produced.  They drive tubines for electric power with the same principal!

Sounds like the pipe above in the drain inlet is too small or somehow restricted in high-flow conditions, and allows water to over-top the structure and into YOUR yard - a huge problem.  Time for a civil engineer or landscape ARCHITECT (not a "landscaper") to get you a solid solution that will stop this from occuring...maybe it will call for ripping out the pipe that the inlet dumps into and making it bigger.  

Not a cheap solution, but knocking a building off of its foundation isn't either!

Good luck ~M