1. Texas Height Modernization and Texas Spatial Reference Center Gary Jeffress, Ph.D., RPLS Director, Conrad Blucher Institute for Surveying and Science Texas A&M University-Corpus Christi

2. It is about better measurement of heights or elevations in Texas How high above Mean Sea Level? Do I live in a flood zone? Can I get flood insurance?

3. Why do we need accurate elevations? Lives are lost and $Billions of property are lost. Austin, 1991 Houston, 2001

4. Flooding in Austin 2001

5. Flooding in Central Texas in 2002 on the Guadalupe River

6. More recently El Paso, July 2006

7. The cost of flooding in Texas Dates Dec 18 to 23, 1Dec 18 to 23, 1991 Oct 17-18, 1998 June 6 to 9, 2001 Nov 15, 2001 June 30- July 7, 2002 LocationCentral Texas South Central Texas Southeast Texas (Houston) Central Texas South Central Texas Max. Rainfall 15.5 in.30 in.36 in.14 in.35 in. Deaths 1032221012 Approx. Damage $43 Million $1.5 Million $5 Billion $11.4 Million $1 Billion From www.floodsafety.com

8. What about coastal waters?

9. NAVDNGVD

13. So, the US Quad sheets are very out-of-date. Hence, the need for Stratmap and LIDAR Mapping. What controls this new mapping?

14. Many benchmarks have been destroyed, or worse, unreliable.

15. The solution….

17. How do we observe elevation? Using a level instrument and Rods graduated in feet.

18. Modern levels are digital

19. VERTICAL DATUMS A set of fundamental elevations to which other elevations are referred. H h Ellipsoid GRS80 H = Orthometric Height (NAVD 88) N Geoid Mean Sea Level H = h - NH = h - N TOPOGRAPHIC SURFACE h = Ellipsoidal Height (NAD 83) N = Geoid Height (GEOID 03) GEOID03

20. COMPARISON OF VERTICAL DATUM ELEMENTS NGVD 29 NAVD 88 DATUM DEFINITION 26 TIDE GAUGES FATHER’S POINT/RIMOUSKI IN THE U.S. & CANADA QUEBEC, CANADA BENCH MARKS 100,000 450,000 LEVELING (Km) 102,724 1,001,500 GEOID FITTING Distorted to Fit MSL Gauges Best Continental Model

21. Texas Height Modernization Goals Re-establish NAVD 88 elevations in Texas to national (NGS) standards. Train Texas Surveyors and Engineers to establish elevations to NGS standards. Connect NAVD 88 heights to Texas Coastal Ocean Observation Network. Determining valid NAVD 88 heights for Texas CORS Antenna Reference Points. Expand the use of GPS for elevation determination.

22. Texas Height Modernization Goals Determine elevations for all Hurricane Evacuation Routes in Texas. Upgrade leveling software and procedures. Establish Texas Spatial Reference Center. Build an online data reference warehouse.

23. Results for First Year Trained 520 surveyors on NGS leveling techniques. TSPS/TxDoT Seminars in –Houston 371 –Arlington 48 –San Antonio 58 –Laredo 22 –Austin 20

24. Results for First Year Let 22 field work contracts to Texas surveying companies for GPS leveling to NGS standards. 68 GPS on Benchmarks $68,000 private sector funding Results will improve GPS elevation observations

25. GPS on NAVD 88 Benchmarks To improve in the national GEOID model Observations to TM59 standards by 22 private surveyor contractors

27. Results for First Year 250 kilometers of Hurricane Evacuation Route Surveys –Jefferson Co. 60 km –Calhoun/Victoria Co. 40 km –Nueces Co. 90 km –Cameron Co. 30 km

28. Hurricane Evacuation Route Elevation Profiling Perform hurricane evacuation route surveys using the Applanix Pos-LV system. –Applanix system allows a vehicle to log accurate 3-D data by combining GPS + inertial sensors.

30. Results for First Year NAVD 88 elevations on four CORS sites –Port Aransas –Corpus Christi –Sanderson –Del Rio

31. Texas CORS Stations u u u u Stations re-observed by Texas Height Modernization program Corpus Christi CORS Del Rio CORS Sanderson CORS National CORS 60 TXDoT 3 H/G Subsidence Dist. 63 Total Co-op CORS (not plotted) 28 (online as of September 2006)

33. Side view from NGS site Antenna side view from site TXCC

34. TXCC CORC A CORC B 211.462m 234.742m Connecting Corpus Christi CORS to NGVD 88

35. Corpus Christi CORS ARP 17.33 m NAVD 88 ARP (old 2002) 17.317 m NAVD 88 ARP (new 2006) (to be published as 17.32 m) Antenna hardware changed 2003

36. Results for First Year Software to streamline digital level observations designed and coded. Software successfully field tested. Results in estimated 50% increased efficiency in operator training time and field observation time.

37. Software Development

38. Results for First Year Texas Spatial Reference Center. Letter of direction from Governor Rick Perry to establish TSRC at Texas A&M University-Corpus Christi. Formal request submitted to Texas A&M University System.

39. GOVERNOR PERRY DESIGNATES TEXAS A&M CORPUS CHRISTI TO HOST THE TEXAS SPATIAL REFERENCE CENTER

40. Connect Texas Elevations to Texas Coastal Ocean Observation Network

41. CORS on NOS Tide Gauge Proposed Location NOS Gauge - Galveston Pleasure Pier In cooperation with Harris-Galveston Coastal Subsidence District

42. End of presentation. Beginning of solution….

43. Thank you for listening.