1. Synthesis & Local Perspectives Shoreline and Marine Boundaries Workshop

2. Measurement- Management-Policy

3. Tidal Datums Semidiurnal, Mixed Tides along the California Coast Semidiurnal, Mixed Tides along the California Coast Mean High Water (MHW) is the boundary for littoral ownership around the globe Mean High Water (MHW) is the boundary for littoral ownership around the globe MHW is also known as Mean High Tide Line (MHTL), Ordinary High Tide Line (OHTL) and Ordinary High Water Line (OHWL) MHW is also known as Mean High Tide Line (MHTL), Ordinary High Tide Line (OHTL) and Ordinary High Water Line (OHWL) Mean Lower Low Water (MLLW) is the base line (0.00 elevation for Tidal Heights at a given location. Mean Lower Low Water (MLLW) is the base line (0.00 elevation for Tidal Heights at a given location.

4. Consolidated Borax, Ltd vs. Los Angeles Landmark Case in 1936 Landmark Case in 1936 –Supra 296 U.S. at 22, 1936 –Read Shalowitz (Vols 1,2 & 3) –Determines That MHW is the Littoral Boundary –Special Master determines that a 18.5 year cycle is required to determine the MHW

5. Teschenmacher vs. Thompson Neap Tides Are Out Neap Tides Are Out –18 CA 11, 21-22 (1861) “Neap tides will not be considered in determining the MHWL. All Tides shall be considered. “Neap tides will not be considered in determining the MHWL. All Tides shall be considered.

6. 1851 Swamp Lands Act Congressional Act in 1851 granted the State of California sovereignty over all tidelands, swamp and overflow lands and navigable waterways within the State. Congressional Act in 1851 granted the State of California sovereignty over all tidelands, swamp and overflow lands and navigable waterways within the State. California Rule California Rule –Artificial Accretions belong to the State

7. Sexy NAD 83 NAD 83 was received with great hoopla and enthusiasm NAD 83 was received with great hoopla and enthusiasm NAVD 88 snuck in the back door and is still lingering in the hallway NAVD 88 snuck in the back door and is still lingering in the hallway Tidal Bench Mark in Canada Tidal Bench Mark in Canada Heights (Elevations) based on the Ellipsoid Heights (Elevations) based on the Ellipsoid –GPS Satellites are Bench marks

8. National Height Modernization Program Began in 1995 Began in 1995 –Congressional Report Rep Charles Taylor (R-NC) Rep Charles Taylor (R-NC) Rep Julian Dixon (D-CA) Rep Julian Dixon (D-CA) Report Mandated by Congress Report Mandated by Congress Monies being Earmarked for some States Monies being Earmarked for some States California gets $1 Million per Year for CSRC California gets $1 Million per Year for CSRC HTMOD Projects in CA & NC HTMOD Projects in CA & NC Will stabilize vertical datums Will stabilize vertical datums

9. Horizontal & Vertical Datums NAD 83 is US Focused NAD 83 is US Focused WGS 84 is Global WGS 84 is Global Geodial models from different sources Geodial models from different sources Heights Heights –Orthometric Changes Daily, You Are Sitting on It) Changes Daily, You Are Sitting on It) –Geoidal Forces of Gravity and Planetary Pull Forces of Gravity and Planetary Pull –Ellipsoidal GPS Satellites are the Bench Marks GPS Satellites are the Bench Marks

10. Navigation & Aviation Uses WGS 84 for All Civil Commercial and Military Aviation Uses WGS 84 for All Civil Commercial and Military Aviation Elevations are based on Orthometric Datums Elevations are based on Orthometric Datums Two Suppliers of Datum Data in the US. Two Suppliers of Datum Data in the US. –NGS –NGA (NIMA)

11. Datums Are Critical Geospatial Information based on a Uniform Datum Plane is Critical to our Future Geospatial Information based on a Uniform Datum Plane is Critical to our Future –National Security –Economy –Natural Resource Management