WRAL WeatherCenter Blog

# When you post lake levels on-air you have normal level for Kerr lake at 295.5 ft. Not true..normal level is 300 ft. Would you please correct this?

Posted March 11, 2008

MIKE MOSS SAYS:         Jerry,    While the other three lakes all have a static normal throughout the year ("guide curve" in Corps of Engineers lingo), Kerr Lake has a curve/normal that varies the desired target elevation throughout the year to manage the lake level for a combination of power generation, recreational, water supply, downstream flow, and wildlife management purposes, with a low of 295.5 and a high of 302.0 feet. You can see a graphical representation of this, along with observed levels, at

http://epec.saw.usace.army.mil/jhkrelev.jpg

For comparison, here are links to similar graphs for Jordan and Falls lakes illustrating the single year-round target elevations:

http://epec.saw.usace.army.mil/BEJelev.jpg

http://epec.saw.usace.army.mil/FLPelev.jpg

Note that these graphs are for the year 2005, as more recent graphs from the Corps of Engineers only show two weeks of data at a time and do not give as good a picture of the variation of "normal" at Kerr. We also generate our own lake level graphs that show both the observed and guide curve elevations, updated around lunchtime Monday through Friday. You can find those at

http://www.wral.com/weather/page/1956847/

It's possible that the 300 ft level you mention is a full year average elevation for Kerr (I haven't done the math to check, but a little "visual averaging" on the guide curve makes it look more like 298 feet or so to me), but we felt that when the lake is intended to run as near as possible to 295.5 feet for a full three months, for example, as it is from December through February, it would be misleading to use a number other than 295.5 as "normal" for that time period. Otherwise, if they somehow controlled the lake perfectly through those months, with a an actual elevation of 295.5, our graphic would make it appear that the lake is stuck at 4.5 feet below normal!

Hope that helps...

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