Height Modernization and Real Time Network
Date Completed: 2012
Cost: $255,710
When the FEMA Digital Flood Insurance Rate Maps (DFIRM's) for Mohave County became effective in November, 2009, they were mapped in the new North American Vertical Datum (NAVD) of 1988. In 2008, the vertical datum used in Mohave County was the older National Geodetic Vertical Datum (NGVD) 1929. In order to assist our local professionals in submitting data and surveys that relate to the new FEMA mapping in the correct vertical datum, the Mohave County Flood Control District funded the NAVD-88 Height Modernization Project which established a primary network of 57 NAVD-88 survey control points approved by the National Geodetic Survey (NGS) throughout the 13,400 square mile area of Mohave County.
The Height Modernization Project was done in two phases. The first phase was in the southern, more populated areas of Mohave County while the second was for the northern (north of the Grand Canyon) areas. These field operations consisted of multi-agency participation within and around Mohave County and the State. Each agency volunteered operators, equipment and vehicles to accomplish the required measurement data collection at various points across Mohave County. The cost of the Height Modernization Survey was $119,922 after receiving $30,000 in grant funding.
Once the primary network of 57 NAVD 88 control points was established, the task of developing a secondary network of reliable benchmarks in our populated areas was addressed by partnering with National Geodetic Survey (NGS) and the State of Arizona to develop a seven station Real-Time Network (RTN) that encompasses the most populated areas of the county. The network is accessible at no cost to any user and uses Global Navigation Satellite System base stations to support surveying activities within the network in Mohave County with 1-5 centimeter accuracy. The cost for the Real Time Network was $135,788.
