On the side of my house I have a slop that I want to grade.i attached a quick mock up of what it looks like: At the top of the slop is my fence. At the bottom of my slop is a retaining wall (approx 4ft in height) of loose rocks. The rocks outline the property line.

If I want to grade this slop, all i have to do it move dirt from one side to the other, right? Anything else i should consider besides drainage? (i have outlined in green what i want to change it to)

Answers to Q: I didnt build the retaining wall. I dont know what the slop is. i cant drive a mower on there without flipping. The height diff. between the bottom of fence and the rocks is approx. 6ft. I added some Pics and updated mock up. I will be doing the grading with a skid steer The rocks range in size. 8-12 inches at its smallest, and 16-24 at the largest. I live in Rockland, NY I dont know the type of soil i have, but there is rocks everywhere i dig - hence the name rockland county. I plan of replanting the slop. right now its just grass and weeds.


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  • What's on the other side of your fence in terms of soil level? Is the soil level on the other side the same as the top of your slope?
    – Bamboo
    Aug 5, 2018 at 18:28
  • On the top, where the fence is, it's even with the other side of fence. On the other side of the retaining wall, the bottom part, it's pretty even with the other side of the retaining wall. There is approx 40 ft difference between the fence and rocks.
    – Padawan
    Aug 5, 2018 at 19:56
  • Was thinking about a 3 ft retrain wall below the fence and utilize that rock wall as another retaining wall
    – Padawan
    Aug 5, 2018 at 20:00
  • 1
    Is there any batter on the retaining wall, ie does it need to lean in to the expected soil to prevent it being pushed over? How is the fence at the top anchored into the ground? Concrete? Aug 5, 2018 at 20:01
  • Yet another question. I assumed the hash marks at the bottom were plants? Is this your loose rock wall? Are you asking to fill behind that wall with the dirt (fill)? If this is so, you have a great opportunity to put drain pipe and grave behind the wall as well as deciding on 'dead men' going into the slope to hold the wall against the surcharge.
    – stormy
    Aug 5, 2018 at 21:59

1 Answer 1


What is the height or rise in elevation from your fence to that wall? What is the horizontal distance from your fence to the wall? Rise/Run = slope 6' of rise over 24' of run gives you a 25% slope. Making your slope less rounded and a straight shot will increase the speed of water flowing down your slope.

If that wall is not engineered or built properly you might have problems. Your 'surcharge' (the water in the soil behind and above the retaining wall) might be less but the erosion going over your wall will be more.

Did you build that retaining wall? What material? Is there a drain pipe behind and at the footing of this wall? Is there a foundation of sorts beneath your wall? Or is your wall a 'talus slope' of rock debris? Boulders? Please send a picture of your wall.

How will you be grading this slope theoretically? A big excavator? Or by hand? What is the square footage of this area (width X length or a side times another adjoining side)? Make sure that the elevation starts 2" minimum below your fence. There should be no soil or mulch or vegetation touching the bottom of your fence. If this is a rip rap retaining wall system, cutting that curve off your slope might overwhelm your wall with erosion and speed of water.

Grins. I don't know if I am looking at a slope of 100 feet or 5' in width. Where is your home? Above slope or down slope? That is very important! Please send pictures. This drainage stuff is kind of my forte. I taught this for college students. Changing drainage will always affect your neighbors unless the water is contained within your site only. There are laws and regulations about this we might need you to look into when you are able to send more information and pictures.

I'll eliminate all of these questions to answer and tell you what you need to know. Please fire questions to me back if you don't understand what I am asking.

I am sorry for all the questions within a non - answer. This is not an answer, just easier to ask all these questions.

Another question is WHERE exactly do you want to move the soil? Behind the fence or below the rocks? Uphill or downhill? Are these loose rocks in a gabion or just a 'talus' slope or are these boulders (larger than 18 to 24 inches or 2 man rock...takes 2 men to life said rock versus a rock that one man can lift or 3 man rock that takes 3 men to life, this is real)!

Where is it that you live? What kind of soil do you have? Are you planning to replant this slope? What is planted on it now? Have you considered terracing? Making steps out of the slope?

  • I updated the post. Please take a look.
    – Padawan
    Aug 9, 2018 at 4:23
  • @Padawan Still not clear what is your desired grade in that area. Aug 9, 2018 at 4:36
  • I want to be able to walk on there. 2 % maybe.
    – Padawan
    Aug 9, 2018 at 4:43

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