From: Nick Brearley <nick@landform.co.uk>
> pethier@comcast.net wrote:
> >> One small point, could that datum be
> >> plus 694.10 feet?
> >>
> >
> > It's all in how you look at it. We say "minus" because the USGS number on
>a
> plan is larger than the City Datum number.
> >
> > USGS sea level reading - 694.10 = Saint Paul City Datum
> >
> Right... I see now. Any UK surveyor working in the US is going to need a
> speedy re-education course, and vice versa.
Maybe not, depending on location. I'm sure there are newer communities which
have all their records in USGS sea-level numbers.
> > Sometimes a surveyor will not call for benchmarks and just pick a random
>place
> on the site and call it "100.00". I hate that. When you design a house,
>you
> should know the elevation of available sewer. It is expensive and annoying
>to
> make sludge flow uphill. The builder ought to spec the job for the surveyor
>to
> supply elevations tied to a standard.
> >
> >
> As a contractor I find that method of levelling (temporary bench mark)
> easier to work with.
Except that you can't look a plan so marked and know the elevation of the city
sewer. Build the footing of your basement lower than the sewer and see how
easy things become.
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