1. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES Updating the International Great Lakes Datum Laura Rear McLaughlin Center for Operational Oceanographic Products and Services September 16, 2014 Tomah, Wisconsin

2. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES The International Great Lakes Datum  History  Roles and Responsibilities  Field Campaigns  Known Unknowns  Impacts  Possible Partnerships

3. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  History  United States and Canada share management of water resources in the Great Lakes and Interconnecting Channels  Common Datum, IGLD, first defined in 1955 by bilateral committee - Coordinating Committee for Great Lakes Basic Hydraulic and Hydrologic Data (CCGLBHHD)  Datums of 1903 and 1935 were replaced  NAVD88 and IGLD 1985 based on same reference frame  CCGLBHHD coordinates updates to the Datum, necessary due to isostatic rebound - nonuniform The International Great Lakes Datum

4. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES The International Great Lakes Datum  History  IGLD 1955 was updated in 1992 to IGLD 1985  Updated IGLD 2020 expected to be released in 2025

5. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Roles and Responsibilities  United States and Canada must coordinate update through the Coordinating Committee  United States update is coordinated through NOAA Center for Operational Oceanographic Products and Services (CO-OPS) and National Geodetic Survey (NGS)  Canadian update is coordinated through Fisheries and Oceans Canada, Environment Canada and Natural Resources Canada The International Great Lakes Datum

6. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Roles and Responsibilities  U.S. and Canada coordinate simultaneous measurements for GPS and water level measurements  U.S. and Canada determine master stations to reference Low Water Datum for each lake  U.S. and Canada coordinating development of new Geoid models  Canada 2013  U.S. 2022 The International Great Lakes Datum

7. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Field Campaigns  Water levels  53 U.S. National Water Level Observation Network locations and ~30 Canadian stations are foundation for IGLD update  CO-OPS has identified about 140 additional locations for seasonal water level gauging  Funding will determine actual locations  Gauges are deployed for four months (June-September); will take seven years to complete (2017-2023);  Datum name is the center year of the measurements The International Great Lakes Datum

8. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES The International Great Lakes Datum Operating U.S. and Canada stations

9. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES The International Great Lakes Datum Possible Seasonal Gauges

10. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Field Campaigns  GPS  NGS to conduct joint GPS campaign in FY15 and FY20 (with Canada)  GPS measurements will occur at bench mark locations at presently operating water level gauges  GPS measurements/leveling also at seasonal sites The International Great Lakes Datum

11. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Known Unknowns  Calculating Low Water Datum – U.S. and Canada will determine the LWD's and methodologies used to determine these elevations.  Accuracies of dynamic heights without running leveling lines  Determination of master stations and nodal points for each Lake  Comparative analysis of past GPS campaigns  Are Gravity measurements needed at the master stations?  Common geoid for US and Canada The International Great Lakes Datum

12. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Known Unknowns  Will nautical charts and shoreline information need to be updated?  How much funding will be available for seasonal water level gauging?  Will hydraulic correctors be used? Will they be larger/smaller/the same?  How will anomalous water level variations at Green Bay and Saginaw be handled?  How will Interconnecting Channels be handled? The International Great Lakes Datum

13. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Impacts  Navigation:  Low Water Datum (LWD or chart datum) will be changed on nautical charts from IGLD 1985 to IGLD 2020  The reference of the shoreline depicted on nautical charts may also change  Chart depths may need to be changed  Under keel clearance may be affected  Environment  Height references for regulating outflows in the Lakes will require adjustment  Flooding/erosion control heights will change  Restoration project datums will be affected  The International Great Lakes Datum

14. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Impacts  Use Planning  IGLD 2020 will be required in new permits submitted to U.S. Army Corps of Engineers (USACE)  Lake level and benchmark elevations will be based on the new datum  Monthly water level bulletins and weekly water level forecasts published by USACE and the Canadian Hydrographic Service will be on the updated datum  Shared water resources between United States and Canada for power generation will be affected The International Great Lakes Datum

15. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES  Possible Partnerships  GPS observations/Local leveling  Seasonal gauges  Master stations  Historic locations  Incorporating data into NGS' Integrated Data Base (Bluebooking Process)  Installing new marks in support of seasonal gauges  Partnering on new CORS stations  Providing feedback on water level needs The International Great Lakes Datum

16. NOAA’s CENTER for OPERATIONAL OCEANOGRAPHIC PRODUCTS and SERVICES Thank you Laura Rear McLaughlin Laura.Rear.McLaughlin@noaa.gov 301-713-2981 x128