At least one coastal scientist believes the severe erosion at Sunset Beach and Waikiki Beach are caused by unusually high tides.  The tides are 3 to 6 inches higher than normal in Honolulu Harbor and at other National Oceanic and Armospheric Administration gauges across the state over the last month.  Dolan Eversole, NOAA Sea Grant Coastal Storms Program coordinator, told the Honolulu Star-Advertiser that a couple of inches of water can make all the difference. City officials are taking action on a temporary fix for the Waikiki Beach erosion. Kalakaua Avenue was closed for 20 minutes between 11 a.m. and noon today while heavy equipment was moved next to the beach.  And, tonight, the makai lane of Kalakaua will be closed between 7:30 p.m. and 3:30 a.m. so sand can be moved from other parts of the beach to the severely eroded stretch of Kuhio Beach.   A long-term solution is being worked out.