1. Montana Height Modernization Curt Smith National Geodetic Survey Idaho Phone: 208-332-7197 Montana Phone: 406-444-0989 Curt.Smith@noaa.gov State of Vertical Control

2. Heights Matter!

3. DESCRIPTION: The Santa Clara River flows past destroyed homes and a fallen tree in the Creek side subdivision Wednesday in St. George. Seven homes in the subdivision were completely lost to the river and at least another four were severely damaged by this week's flooding. CREDITS: Jud Burkett COPYRIGHT: The Spectrum Southern Utah Flooding 1/12/2005

4. DESCRIPTION: A row of damaged homes in Riverwood subdivision cling to the banks of the Santa Clara River Thursday in St. George. CREDITS: Jud Burkett COPYRIGHT: The Spectrum Southern Utah Flooding 1/12/2005

5. North Carolina Floodplain Mapping 2002 Detail Mapping vs. Effective Approximate Mapping

6. Poured in place concrete post 1954 Stainless steel rod driven to refusal 1980’s Physically Monumented Points

7. Current Survey Control NGS Data Sheet www.ngs.noaa.gov

9. NGS Bench Marks

10. Disturbed Geodetic Control Coordinates/Elevations Questionable Destroyed Geodetic Control No Coordinates/Elevation Monumented Points Deterioration

11. USGS Topographic Map F 143 Not recovered (destroyed)E 143 Not recovered (destroyed)D 143 Not recovered (destroyed)C 143 Not recovered (destroyed)

12. 2 nd Order Vertical 1 st Order Vertical 684 - Total Vertical Control Points Listed Lewis and Clark County Vertical Control Points in NGS Database

13. Lewis and Clark County Vertical Control Points in NGS Database 684 - Total Vertical Control Points Listed 176 (25.7%) – Missing 65 - Reported as Destroyed 111 - Reported as Not Found 508 (74.3%) – Possible Vertical Control Points 146 – Total Monumented (no recovery notes) 20 – Reset 1 – Set Within Last 10 Years 362 (52.9%) – Total Recovered in Good Condition 112 – Recovered for NAVD88 (after 70’s) 64 – Recovered Good Within Last 10 Years