Over half a million boats and Personal Watercraft (PWC) are used on Lake Powell each year.  Many boats are powered with 2-stroke engines that can release as much as 30% of their fuel unburned into the water.  To ensure excellent water quality in the future and to mitigate for continued PWC usage on Lake Powell, the National Park Service is required to monitor for hydrocarbon contamination.  Research designed to establish baseline conditions began in 2004 as a cooperative study with the U.S. Geological Survey.  Results for this study indicate that throughout most of the lake, hydrocarbon constituents are below detection limits.  When detected, all hydrocarbons have been at levels considered acceptable by Utah and Arizona standards under the Clean Water Act.