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Modern Vertical Datums and Lake Level

Objectives:  1)  To develop methods to combine GPS ellipsoidal heights, water-level gauge measurements, and leveling data in cone consistent and unified dynamic height system for the future re-definition of the International Great Lake Datum and post-glacial rebound models.  2) To identify the transformational relationships between water-level gauge and satellite-derived lake level measuring and monitoring systems in terms of vertical datum definition and realization, as well as geodynamical processes, such as post-glacial rebound and local subsidence.  Rationale:  Several types of lake level determination and monitoring systems are now available for the Great Lakes: traditional land-based water-level gauges, and new satellite-based altimetry and GPS buoy systems. Each system has a different datum (origin point), and data are obtained with different measurement techniques, over different geographic and temporal scales, and with different types of systemic errors. In addition, geodynamical uplift, such as post-glacial rebound (5 cm/decade), affects terrestrial measurements, but not satellite-based measurements. The problems are to unify these systems in terms of datum shifts, to eliminate systematic errors through mutual calibration, to develop accurate post-glacial rebound models, and to enable detection of other vertical motions of water-level gauges (e.g., due to local subsidence) in order to allow for the consistent and unified analysis of past and future height records using modern and conventional systems for the purpose of determining lake levels over short and long time spans.

In progress
Start Date
End Date
Scope of Study
Scale of Phenomena
Lake Basin Connecting Channels
Lake Erie
State Province
Annex Numbers
Research & Development
Surveillance and Monitoring
Annex 17
Effects of varying lake levels and relation to pollution sources, fate and effects

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Great Lakes - St. Lawrence Region.