Name:   Osms - Subject:   Water level Measurement Date:   6/8/2015 4:48:28 PM

Martin Datum was the old way of measuring the water level and evidently the old way of measuring missed the real sea level by about one foot.  Therefore, while real sea level full pool level is 491' the old way of measuring said it was 490'.  Hey, 90 years ago, I'm surprised they got that close.  Think about surveyors having to figure that out, the old way.  All official, gubment stuff uses 491' mean sea level (msl).