If you have been watching the lake level over the past month or more you would have observed it to be very consistently the same height. If you have been wondering what height, well according to Paul Robertson our Lake Manager the level has been holding right at 9.53’ above Mean Sea Level. To ensure accuracy the District has measured each section of the dam to 18” above the concrete base.
In his letter dated March 5, 2009 OWRD Watermaster, Greg Beaman established this 18” maximum after having the concrete base surveyed at 8.03’ above MSL. Therefore, the most accurate measurement of the lake level is at the dam structure, 8.03’ + 18” or 1.5’ equals 9.53’ above MSL. Observations made this week show water barely flowing over the dam.
If you were a close observer of lake level, you would notice that the staff gauges currently read 9’ 3” or about 3” lower than the reality just described. Indeed this discrepancy was only recently discovered; it appears that when the Oregon Water Resources Department re-established the height of the concrete base of the dam in 2009 they did not re-establish the accuracy of the staff gauges. The OWRD has committed to perform a survey of the gauges sometime in the future. It will take a bit of detective work to determine how many years of historical data were affected by this 3” discrepancy. It is clear that all recent discussions about lake level have been influenced this variance. Decisions have been made using a mixture of field observations and references of lake levels as observed at the dam and measured at the staff gauges.
The good news is that no matter what the recorded level has been the actual level as observed where the water meets land has been correct; and by all reports lake stakeholders seem to be satisfied with the result. Watch for information on updated staff gauges at the DLWID Lake Level Report.