Question
I have just installed an inground pool. My yard slopes so I now have hills from the pool decking down to the fence on 2 of 4 sides. We had to bring in 4 loads of dirt when we installed the pool. I would like to do a deck along the one side that slopes down but will need to keep dirt in place under deck to prevent washout under pool cement deck area...what can I put down or do to keep the dirt in place. The deck will be about 24x12. I am also adding about a 5' stone deck area completely around the cool decking of the pool. Some suggested that I put tarp down under the stones and continue the tarp running down the hill. Will that work? Please give me ideas and suggestions...I need help asap before the dirt washes away!

Answer
Hello Kathy - I thought about this question for a bit...There are literally HUNDREDS of products & solutions that could work.  "Erosion Control" is a sub-industry in landscape world, as there are federal & state laws that dictate their use for projects that could dump soil into waterways and muck things up.

Was the fill compacted when it was placed?  This is important, as retaining relatively compact soil is different than holding back loose, fluffy dirt.  

The tarp & gravel is *NOT* the preferred solution, as you will only create what is called a "failure plane", and the tarp/gravel will slough off of the slope faster than if you did nothing!

The deck itself will act as an erosion control device, as the concrete or wood will prevent water from getting at it  - unless you plan on sloshing lots of pool water at it!

To further ensure the soil stays put, the "stem" or edge of the concrete deck that runs along the slope should be extended at least 18'' down into the slope (24'' would be better, depending on how steep the slope is), or it may get undermined over time, as the soil naturally seeks to level itself.  This will also help the concrete deck from pealing away from the pool coping!  Ask the contractor to install a "stem wall" - if he doesn't know what it is, fire him on the spot!  Similar terms are "core wall" or "cutoff wall", but the principle is the same - to prevent water seepage & excessive concrete settling.

Here is a site for more information on various products for erosion control...

http://www.landscapeonline.com/products/index.php?localtype=manu_imp&searchby=nl...

I might add a mechanical device if it were my pool & slope, like a fiber blanket (Enkamat.com, or similar) or soil reinforcing polymer (dirtglue.com, or similar), even if there will be no vegetation to knit it all together, which is the preferred solution!!


~Marc