Civil Engineering Reference
In-Depth Information
Fig. 13.2
Under Federal law, private ownership of land bordering navigable water runs to high
water, but there are state exceptions
tidal measurement stations along the U.S. coast and tidal datums are available to
surveyors. When the tide moves into shallow water estuaries, tidal heights can be
substantially affected. A tidal datum established for the mouth of a river may not
be applicable for other points further upstream. Because there may not be tidal
data available for many locations in shallow water estuaries it may not be possible
to accurately determine the height of mean high water at these locations without an
actual tidal study. Such a study would probably be considerably beyond the scope
of the average boundary survey. Often, the slope of the shoreline in tidal waters is
very shallow so that small variations in tidal elevations have the potential to cause
substantial differences in the geographic location of the water boundary (Fig.
13.2
).
Some states do not follow the federal rule and do not use mean high water as
the limit of private ownership. California uses neap high tide which is the high
tide level corresponding to the period when the sun and moon are in quadrature
(the sun and moon are about 90° apart as measured from the earth). In another
example, in Massachusetts, a Colonial Ordinance established that an upland owner
owns the bed to low water but no more than 100 rods (1,650 feet) from high
water. New Hampshire and Maine follow the same rule. There are also jurisdic-
tional differences in the ownership of the beds of fresh water ponds and lakes. In
Massachusetts, the beds of ponds over 10 acres, called great ponds, are owned by
the Commonwealth.
