Data from US Geological Survey Water-Resources Investigations 80-24
"Cross Sections of the Hudson River Estuary from Troy to New York City,
New York", by David A. Stedfast, 1980, 70 p.

Disk includes data from Table 1. -- Riverbed elevations of Hudson River
estuary cross sections. Stationing, in feet from east bank. Elevations,
in feet above ngvd 1929. Longitudinal distance, in feet north of the
Battery, NYC. Data is in format to be read by USGS CGAP Program described in
"A Computer Program for Analyzing Channel Geometry", USGS Water-Resources
Investigations Report 85-4335 by R. Steven Regan and Raymond W. Schaffranek,
1985, 49 p. For more information on CGAP visit 
http://water.usgs.gov/software/cgap.html

The two data files included: 
cgapdata153-51.txt -- cross sections from rm 153.7 to 51.6
cgapdata49-21.txt  -- cross sections from rm 49.3 to 21.0

In the entry below the 450.000 column is stationing starting on the east side
of the river at 20.000 feet above mean sea level (ngvd 1929) at river mile
49.3 or 260304 feet above the Battery. Previous lines are information for
cgap. The second cross section point is 30 feet west of the first at relative
position 480.000 feet and has an elevation of 1 foot above mean sea level.

The 6 at the bottom of the file is the process control card (p.41 note 13)
requesting output of cross-sectional area and channel width as functions of
stage stored in a file (.pun). This option uses the parameter record (p.38-
39) " 1  1 -15.00  10.00   1.00   260304" (one per section) to set the min,
max, and stage increment for computations.

Example data file:
HUDSON RIVER           RM 49.30-RM 21.0       1-16
(T12,F10.3,T25,F9.3,T38,I3)
 1  1 -15.00  10.00   1.00   260304
SECTION #110 AT MILE 49.3
 1            450.000      20.000      1
 1            480.000       1.000      2
 1            495.000      -4.000      3
 1            515.000      -5.000      4
 1            532.000      -9.000      5
 1            541.000     -12.000      6
 1            558.000     -17.000      7
 1            566.000     -21.000      8
 1            590.000     -28.000      9
 1            597.000     -32.000     10
.
.
.
   6