CO HT MOD History HT MOD funds 75

CO HT MOD History • HT MOD funds ($75 k) received in 2008 • Outreach efforts conducted in Denver and Grand Junction • Colorado Height Modernization Advisory Board • Inventory of contacts obtained – Federal, State, local agencies • Website • All dissolved

Today • CO HT Mod Team formed • CDOT Regions, NGS CO Advisor • Research on past and current efforts in CO and other States. • Beginning to look at technical aspects

Projects • Region 2 – Southside of CO Springs to Monument, L 27184 • Region 6 – Denver International Airport to Denver to Boulder to Longmont, L 26455

Projects • Region 2 – Southside of CO Springs to Monument, L 27184 • Region 6 – Denver International Airport to Denver to Boulder to Longmont, L 26455 • NGS Research & Development project – Golden to Vail Pass • Region 2 Height Mod Project in Colorado Springs • Woolpert - Denver International Airport – 1 st order leveling and HT MOD • Other projects included resetting 1 – 3 bench marks by Region 2 and Region 6 and contractors.

Differences in Heights

Differences in Heights

In Process Newest

Challenges • • • Determining how good Heights are in Colorado (How good is what we have). We currently know of published data sheets where, when the Ellipsiod Ht. and Geoid Ht. are added together, and the result does not agree with the Orthometric Ht. by a decimeter. There have also been problems with getting the differences from previous 1 st Order leveling r data to agree with recent leveling data differences across the State. Mountainous Terrain. Leveling through and around the mountains is both costly and time consuming. In addition, due to the changes in marks due to unstable ground, uplift and gravity, heights may not be reliable. Identifying and communicating the benefits of Height Modernization to partners within the State to generate funding/resources to accomplish defined goals. Benchmarks rapidly being destroyed; CDOT resources limited to conduct replacements; limited experienced CDOT staff in leveling processes. The increased cost and time to add and complete height modernization surveys for our projects.

Next Steps • Continue Team Effort and Expand to others • Work with NGS to establish procedures to assist with what is needed • Identify what is needed

Thank you! Jonathan Kobylarz CDOT Row and Survey 222 S. 6 th Street Room 317 Grand Junction, CO 81501 (970)683 -6236 jonathan. kobylarz@state. co. us