When I look at the average rainfall vs actual over the past 12 months it appears we are right on target. Yet, Falls Lake is drying up and water rationing is near with the blame placed on the "great drought". It apperas to me the problem may instead be the "great thirst" of Raleigh, using water faster than normal rainfall can replenish...???Posted — Updated
MIKE MOSS SAYS: Les, As you noted, when you track RDU rainfall for the past 12 months, we are only a little over a tenth of an inch below normal. However, there are some other factors to consider, including the fact that part of the reason it is near normal is because of very heavy precipitation last November, together with a couple of periods of rainfall in April and July that were quite substantial for the airport itself, but which happened to be clusters of shower and thunderstorm acrivity that did not cover very much of the area. So, while those events helped RDU to a 12-month total that looks pretty reasonable, many surrounding areas missed out on that rain and there was relatively little that fell into the watershed that feeds Falls Lake. Finally, through the latter half of summer we had some unusually hot weather in combination with very low rainfall totals (we're 3.1 inches below normal at RDU for the past 90 days in spite of the 4.5 inches that fell within the past two weeks) and the combination of demand and evaporation during that period took its toll. As you noted, growth plays a role in enhancing demand as well, but there have certainly been meteorological factors that played into the declining lake levels that were partially masked by the slightly deceptive rains that fell at RDU. When you look at year to date totals for 2007, RDU has received about 82 percent of normal rainfall. For much of the surrounding area, the equivalent calculations show mostly between 50 and 75%, with a few unlucky spots at less than 50%.
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