Tidal datums, and the marine boundaries determined through their estab- 

 lishment, have been an important issue in the Arctic over the past two decades 

 because of ownership claims. Millions of dollars have been at stake in State 

 versus Federal ownership of oil leasing plots. The Bureau of Land Management 

 has been surveying coastal lands for the purpose of restoration of the Federal 

 lands to the State and native corporations; the Extended Jurisdiction Zone (200 

 mile boundary) has been determined; and NOAA has been conducting 

 hydrographic surveys and mapping in the Arctic. The private sector uses tidal 

 datums for artificial island construction, marine operations and other oil industry 

 related activities. These projects all require tide data, to varying degrees of 

 accuracy and for differing lengths of time, that has not been previously available 

 in this region. These requirements, and the inability of standard technology and 

 methods to satisfy them, has resulted in development and experimentation with 

 new and improved procedures and instrumentation in an attempt to collect the 

 needed tide data. 



2.3.3 Dinkum Sands Project 



Much of the search for new technology or procedures for making tide 

 measurements in the polar regions has been performed in cooperation with the 

 State of Alaska and other Federal agencies due to the common need for the data. 

 The most ambitious, and costly, project was the Dinkum Sands project. An 

 attempt was made to collect a full year of data off the coast of the north slope 

 using standard technology (ADR & bubbler gauges) so that the tidal datums 

 established would be defensible in court. Three long-term stations were estab- 

 lished on three small, remote gravel islands for redundancy. The fully enclosed, 

 heated, shelters (see Figure 7) were installed on specially-designed support 

 platforms, heat tracing was used in the steel reinforced stilling wells, heated oil 

 was dripped around the wells to prevent ice formation, bottom-mounted pressure 

 gages supplemented the standard gages, and various other methods were 

 employed to collect the data. Specially designed, sleeved, deep-rod bench 

 marks were installed (and sometimes leveled to) while under ice pack cover. A 

 full year of data was collected at one station at a cost of over $ 1 million. 



Other attempts have centered around installing bottom-mounted pressure 

 gauges but these devices have their own set of problems. Pressure gages are 

 inherently less accurate than ADRs and must be corrected for barometric 

 pressure and density variations; it is difficult to establish a physical reference point 



