Topic: Mass Grading for Multi-Phased Project

[Jeff_M]

OK, It's been a long time since I've had to do something like this and I'm sure there have got to be better ways than we used to do it. Here's what I have, a 22+ acre site that is being subdivided in 3 phases. However, Phase 1 has a lot of cut and Phase 3 has a lot of fill. The idea is (and the City has conditioned us to) perform the full site mass grading with Phase 1. Not knowing how soon the other phases will be built, I don't think that grading to the pads & subgrade for the future phases should be done. If it sits for any length of time and grasses grow, erosion occurs, or whatever, it is still going to need some final grading.

So I guess what I'm asking is, how much grading should be done? Place mounds for the future pads with rough cut roads to direct drainage? BTW, the storm drain infrastructure is to be built with Phase 1 as well since it is at the top of the drainage area. We will place temporary inlets at any future road low points. Just curious what others have done in similar cases.

Thanks!

[mjfarrell]

I think I would grade phase 1 as required, then waste the excess cut across the other two phases in such a manner that you were placing 4-5 inches of over burden on phase 2-3.  I wouldn't really grade the future low spots low, as one wouldn't want any soils to enter the drainage system should the temporary covers on the inlets leak. In fact I might even grade them higher.
The intent being that later as the sites are regraded the soils can be shaped and re-compacted to proper specification within the roadways and parking areas, then if one is short on material the pad areas can be adjusted with base course, or select materials as required. i would also keep any grades on phases 2-3 as flat as possible to limit the potential for erosion to occur.

One might also consider creating a small nuisance berm around the site to prevent offsite flows onto the site, and to prevent the preliminary grading from being disturbed by vehicles.