DEPARTMENT OF THE ARMY ER 1110-2-8160
U.S. Army Corps of Engineers
CECW-CE Washington, DC 20314-1000
CECW-CO
CECW-P
Regulation
No. 1110-2-8160 1 March 2009
Engineering and Design
POLICIES FOR REFERENCING PROJECT ELEVATION GRADES
TO NATIONWIDE VERTICAL DATUMS
1. Purpose
. This regulation establishes U.S. Army Corps of Engineers (USACE) policies for
referencing project elevation grades to nationwide vertical datums established and maintained by
the U.S. Department of Commerce. Its purpose is to ensure that controlling elevations and local
datums on USACE projects are properly and accurately referenced to nationwide spatial
reference systems used by other Federal, state, and local agencies responsible for flood
forecasting, inundation modeling, flood insurance rate maps, navigation charting, and
topographic mapping.
2. Applicability
. This regulation applies to all USACE commands having responsibility for the
planning, engineering, design, construction, operation, maintenance, and regulation of flood risk
management and coastal storm damage reduction, hurricane protection, multi-purpose water
supply/control and hydropower, ecosystem restoration, and navigation projects. This regulation
also applies to regulatory permitting activities.
3. Distribution. This regulation is approved for public release; distribution is unlimited.
4. Policy. It is the policy of the USACE that the designed, constructed, and maintained
elevation grades of projects shall be reliably and accurately referenced to a consistent nationwide
framework, or vertical datum—i.e., the National Spatial Reference System (NSRS) or the National
Water Level Observation Network (NWLON) maintained by the U.S. Department of Commerce,
National Oceanic and Atmospheric Administration (NOAA). The current orthometric vertical
reference datum within the NSRS in CONUS is the North American Vertical Datum of 1988
(NAVD88). The current NWLON National Tidal Datum Epoch (NTDE) is 1983-2001. (Other
NSRS/NWLON defined datums are applicable in the Great Lakes and in isolated OCONUS
regions). The relationships among existing, constructed, or maintained project grades that are
referenced to local or superseded datums (e.g., NGVD29, MSL), the current NSRS, and/or
hydraulic/tidal datums, shall be established as outlined below.
a. Hurricane & Shore Protection Projects (HSPP). In coastal areas subject to tidal influence,
hurricane and shore protection design or constructed grades shall be directly referenced to
NWLON tidal gages and coastal hydrodynamic tidal models established and maintained by the
U.S. Department of Commerce (NOAA).
