View Full Version : Building in a wash (AZ)
04-13-2010, 02:49 AM
I have a client whose house sits built up above a wash, about 7-10 below. He wants to build in the wash (AZ Phoenix area), essentially replacing the floor of the wash with pavers of some sort. The wash sustained no water after a 3-day rainfall, and is only fed by small hills (not large mountains and not connected to larger washes). The question is, will the new "floor" hold up over time? Or, what material/paver could be used to make this happen?
One end of the house is perched 10' above the wash, and the other end is about 4' above, creating a natural path into the wash. Stairs could be built down to the wash. Wash is about 2-8' wide, and there is a natural area that he wants to serve as a 8' diameter patio. Entire project is to look as natural as possible, blending into surroundings.
There are no floods, he doesn't mind during rain that the wash delivers whatever it carries onto the surface and he'd have to clean it. In Phoenix, he foresees few days a year he'd have to do this.
04-13-2010, 09:37 AM
I thought Maricopa County had ordinances against building in a wash? May be worth looking into. (yes, I'm in VA, but I used to work in PHX)
04-14-2010, 07:20 PM
City/County would definantely have a problem with this, as would the HOA, if there is one. It is not that the wash holds water after the event, it is that the wash has water flowing in it during the event. I would imainge that the flowing water will undercut your patio and wash it out leaving you with an unhappy homeowner.
Superior L & L
04-17-2010, 05:48 PM
Ok now im interested !! what is a wash? sorry but im from the north!
04-20-2010, 07:21 AM
Its basicaly a natural ditch in the desert that channels water during a large rain event. People dont realize desert can have nasty flash floods. Its alot more then surrounding terrain you need to look out quite a few miles to actually see where the water will come from.
I remeber doing a gov min maintence road for heavy traffic area through a "sensitive" wash on base. Both sides was bordered by indian cliff glyphs. The road was large gravel base haul about three miles long. Anyways just as we moved out and a regiment was moving thru a huge storm blew in. We had to take all equipment and actually park it on the mountainside as the old goats knew what was coming. Almost instant boulder tossing torrents of water came crashing down the wash. All gravel was instantly displaced and created nasty basin at the base of the valley floor.
Anyways we almost lost a lowboy with D7 on the back. The flood actually washed the sand out underneath it and placed it sideways. The operators lived by standing on the D7 as it was slowly turn it self over. A LAV company lost eight men as they didnt have time to displace from the position at the basin floor.
Alittle extreme story for a small landscape project but it gives you a example what kinda forces you can find at times. Sand works completely different when saturated and is allowed to flow. I wouldn't put anything in any sort of wash with out super expensive over engineered controls which could even cause bigger problems when you consider what the water will do once it has area to pool in. Sometimes is best not to mess nature.
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