This report was commissioned by GCPBA for the benefit of the private boater. John Vrymoed, author of the report, is a registered civil and geotechnical engineer in California, now retired. He is a published author on topics related to earthquake engineering and dam performance, has served on a panel of experts for the U.S. Army Corps of Engineers, and has given presentations at various conferences.
Synopsis: The purpose of this report is to define the Colorado River's high water level's location and thereby assist the private boater in recognizing the extent of the disputed boundary between Grand Canyon National Park and the Hualapai tribal lands. The Colorado River historic high water level within the Grand Canyon is determined to be 80 feet above a base flow of 8,000 cfs between Lees Ferry and the confluence of the Little Colorado River, and 100 feet above the base flow from there to the Grand Wash Cliffs.
Read the full report here: Colorado River High Water Mark Report